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Regulation and function of interleukin-36 cytokines in homeostasis and pathological conditions
Abstract
IL-36α, IL-36β, and IL-36γ are members of the IL-1 family of cytokines that signal through a common receptor composed of IL-36R and IL-1R/AcP to activate NF-κB and MAPKs, such as p38 and JNK, and promote inflammatory responses. IL-36Ra is a natural antagonist of the 3 IL-36 agonists that binds to IL-36R and inhibits binding of the agonistic ligands. These cytokines are expressed predominantly by epithelial cells and act on a number of cells, including immune cells, epithelial cells, and fibroblasts. Processing of the N terminus is required for full agonist or antagonist activity for all IL-36 members. The role of IL-36 has been demonstrated extensively in the skin, where it can act on keratinocytes and immune cells to induce a robust inflammatory response and is implicated strongly through functional and genetic evidence in the pathology of psoriatic disorders. Emerging data also suggest a role for this cytokine family in pulmonary physiology and pathology. Although much has been learned about the biochemistry of IL-36 and its role in various tissues, it is clear that we are at an early stage in our understanding of the full biology of these cytokines.
© Society for Leukocyte Biology.
... A biological inhibitor to this complex has also been identified, the IL-36R antagonist (IL-36Ra). The IL-36 cytokines and their receptor are expressed by several tissues, particularly the lung, skin and intestine, as well as by immune cells such as monocytes, macrophages, dendritic cells (DCs) and T cells [3,4]. Similar to other IL-1 family members, IL-36 cytokines are important activators of the inflammatory response, stimulating both innate and adaptive immune responses [3,4]. ...
... The IL-36 cytokines and their receptor are expressed by several tissues, particularly the lung, skin and intestine, as well as by immune cells such as monocytes, macrophages, dendritic cells (DCs) and T cells [3,4]. Similar to other IL-1 family members, IL-36 cytokines are important activators of the inflammatory response, stimulating both innate and adaptive immune responses [3,4]. These cytokines have been shown to play an important role in autoimmune diseases, in particular in the pathogenesis of psoriasis [3,5], Inflammatory Bowel Diseases [6,7] and respiratory diseases [8]. ...
... Similar to other IL-1 family members, IL-36 cytokines are important activators of the inflammatory response, stimulating both innate and adaptive immune responses [3,4]. These cytokines have been shown to play an important role in autoimmune diseases, in particular in the pathogenesis of psoriasis [3,5], Inflammatory Bowel Diseases [6,7] and respiratory diseases [8]. Given that inflammation is now recognised as a hallmark of cancer, IL-36 is now being increasingly investigated in, and implicated in, multiple cancer types. ...
The IL-36 cytokines are a recently described subset of the IL-1 family of cytokines, shown to play a role in the pathogenesis of intestinal diseases such as Inflammatory Bowel Disease (IBD). Given the link between IBD and colitis –associated cancer, as well as the involvement of other IL-1 family members in intestinal tumorigenesis, the aim of this work was to investigate whether IL-36 cytokines play a role in the pathogenesis of colon cancer. Whilst research to date has focused on the role of IL-36 family members in augmenting the immune response to induce tumour rejection, very little remains known about IL-36R signalling in tumour cells in this context. In this study we demonstrate that expression of IL-36 family member mRNA and protein are significantly increased in colorectal cancer tissue compared to adjacent non-tumour. In vitro assays showed stimulation of colon cancer cell lines with IL-36R agonists resulted in the activation of the pro-tumorigenic phenotypes of increased cellular migration, invasion and proliferation in both 2D and 3D models. In addition, the IL-36 cytokines induced strong expression of pro-inflammatory chemokines in both human and murine cell lines. Intraperitoneal injection of IL-36Ra significantly reduced tumour burden using the subcutaneous CT26 tumour model in syngeneic Balb/mice, and this was associated with a decrease in Ki-67 expression by tumour cells in the IL-36Ra- treated group relative to untreated, suggesting the inhibition of the pro-proliferative signalling of IL-36 agonists resulted in the decreased tumour size. Moreover, colon cancer cells lacking the IL-36R also showed reduced tumour growth and reduced Ki-67 expression in vivo. Taken together, this data suggests that targeting IL-36R signalling may be a useful targeted therapy for colorectal cancer patients with IL-36R ⁺ tumour cells.
... IL-36 isoforms are expressed by a broad variety of tissues and multiple cell types with their ultimate effects depending on a fine balance of their concentrations, the cellular target or the phase and context of the disease (11,14,15). Therefore, IL-36 has been implicated in multiple diseases with an inflammatory component including psoriasis, inflammatory bowel diseases, arthritis and joint diseases, renal and pulmonary injuries and even cancer (14,16), but little information about the impact of IL-36 on obesity-associated inflammation exists (17)(18)(19). Higher circulating levels of IL-36g and IL-36a together with decreased levels of IL-36Ra have been found in patients with obesity (19) and T2D (18). ...
... IL-36g is crucial in the regulation of immune responses and chronic inflammatory and fibrotic disorders (11,14,16). However, little is known about its regulation and functions in the AT inflammation in obesity. ...
... The upregulated gene expression levels of IL36G in the VAT and PBMC in obesity strengthen the role of the cytokine in inflammation. However, it has to be stressed that IL-36 family members exhibit a dichotomous nature in inflammation in different sites, with the possibility that the increase in its constitutive basal expression levels drive the production of proinflammatory cytokines to the benefit of the host (15,16,47). Following activation, IL-36 mediates its biological effects by binding to IL-36R which is expressed by numerous cell types (16). ...
Interleukin (IL)-36 is a recently described cytokine with well-known functions in the regulation of multiple inflammatory diseases. Since no data exists on how this cytokine regulates adipose tissue (AT) homeostasis, we aimed to explore the function of a specific isoform, IL-36γ, an agonist, in human obesity and obesity-associated type 2 diabetes as well as in AT inflammation and fibrosis. Plasma IL-36γ was measured in 91 participants in a case-control study and the effect of weight loss was evaluated in 31 patients with severe obesity undergoing bariatric surgery. Gene expression levels of IL36G and its receptor were analyzed in relevant human metabolic tissues. The effect of inflammatory factors and IL-36γ was determined in vitro in human adipocytes and macrophages. We found, for the first time, that the increased (P<0.05) circulating levels of IL-36γ in patients with obesity decreased (P<0.001) after weight and fat loss achieved by Roux-en-Y gastric bypass and that gene expression levels of IL36G were upregulated in the visceral AT (P<0.05) and in the peripheral blood mononuclear cells (P<0.01) from patients with obesity. We also demonstrated increased (P<0.05) expression levels of Il36g in the epididymal AT from diet-induced obese mice. IL36G was significantly enhanced (P<0.001) by LPS in human adipocytes and monocyte-derived macrophages, while no changes were found after the incubation with anti-inflammatory cytokines. The addition of IL-36γ for 24 h strongly induced (P<0.01) its own expression as well as key inflammatory and chemoattractant factors with no changes in genes associated with fibrosis. Furthermore, adipocyte-conditioned media obtained from patients with obesity increased (P<0.01) the release of IL-36γ and the expression (P<0.05) of cathepsin G (CTSG) in monocyte-derived macrophages. These findings provide, for the first time, evidence about the properties of IL-36γ in the regulation of AT-chronic inflammation, emerging as a link between AT biology and the obesity-associated comorbidities.
... 23 Epithelial cells, including keratinocytes, are sources of cytokines of the IL-1 family (IL-1F), consisting of 11 members with its most common nomenclature (and alternative names in parentheses): IL-1␣, IL-1, receptor antagonist of IL-1 (IL-1RN), IL-18, IL-33, IL-36␣ (IL-IF6), IL-36 (IL-1F8), IL-36␥ (IL-1F9), IL-36Ra (IL-1F5), IL-37 (IL-1F7) and IL-38 (IL-1F10). 24 The corresponding receptors are named as follows: for IL-36␣ and , IL-1Rrp2 and IL-1RAcp receptors, expressed in monocytes, T and B lymphocytes; for IL-36␥, the receptors are the same but expressed in keratinocytes and epithelial cells; for IL-36Ra, the receptors are IL-1Rrp2 and SIGIRR, expressed by keratinocytes, monocytes, and dendritic cells. 18 Members of IL-36 use the same IL-36R receptor, with the first three showing similar levels of agonist activity after binding, but the binding to IL-36Ra does not initiate a signaling response; therefore, it is considered antagonistic (Fig. 2). ...
... 18 Members of IL-36 use the same IL-36R receptor, with the first three showing similar levels of agonist activity after binding, but the binding to IL-36Ra does not initiate a signaling response; therefore, it is considered antagonistic (Fig. 2). 23,24 The expression of IL-36␥ was located in the granular layer of the epidermis, especially in peripustular keratinocytes. The IL-36␣ expression has also been strongly detected in the superficial layers of the epidermis in GPP lesions and psoriasis plaques. ...
... 23 It has also been demonstrated that IL-36 is able to activate the vascular endothelium, leading to significant plasma extravasation, resulting in marked edema of the papillary dermis, extravasation of red blood cells, and other cells, such as eosinophils. 23,24 The expression of Th17/Th1-related cytokines, such as IL-17A, IL-22, IL-23p19, IFN-␥, and IL-18, is increased in plaque psoriasis when compared to GPP and normal skin. IL-17A induces IL-36 expression more intensely in psoriasis-derived human keratinocytes than in healthy keratinocytes. ...
Generalized pustular psoriasis (von Zumbusch) is a rare and acute eruption characterized by multiple sterile pustules over an erythematous and edematous background, eventually associated with psoriasis vulgaris. Classically, it manifests as a potentially severe systemic picture and demands prompt diagnosis and intervention. The duration of each flare-up and intervals between the pustular episodes is extremely variable. Recently, genetic abnormalities have been identified mainly in the familial and early variants of this disease. The therapeutic arsenal is limited; however, new drugs being evaluated aim to control both pustular flare-ups and disease recurrences.
... The genomic position of IL-38 is near the IL-1Ra and IL-36Ra locus on human chromosome 2p13 [13]. Furthermore, the structural homology of IL-38 with IL-1Ra and IL-36Ra is about 41% and 43%, respectively, whereas this homology is significantly lower (14%-30%) with the other members of IL-1 cytokine family [14]. Because of its structural resemblance with IL-36Ra, IL-38 is supposed to function through IL-36R downstream signaling pathways such as nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) inhibition [15,16]. ...
... Interleukin (IL)-38, the tenth member of IL-1 cytokine family, was discovered in 2001 [12]. Because of its sequential homology with IL-1Ra and IL-36Ra, IL-38 has been supposed to exert anti-inflammatory properties [14]. Various Disease onset (year) ), mean±SD 27.01±15.76 ...
Introduction
Vitiligo is thought to be an autoimmune disorder caused by melanocytes dysfunction and depigmentation. Among different executors of the immune system in developing the disease, the role of various cytokines has been defined.
Objectives
We have focused on IL-38, the tenth member of IL-1 cytokine family with a proposed anti-inflammatory role, which has not hitherto been introduced as an anti-inflammatory factor in vitiligo.
Methods
Sixty-nine generalized vitiligo patients and 72-year-old- and sex-matched healthy individuals were included in this study. IL-38 level was evaluated in sera of all participants using ELISA assay. The relation of IL-38 level to patients characteristics was evaluated.
Results
IL-38 serum level in vitiligo patients (159.5±39.7 pg/ml) was lower than the healthy controls (166.7±34.8pg/ml) (P = 0.039). A weak negative correlation between the age of male patients and their IL-38 serum levels was identified (r = 0.38, P = 0.058). Evaluation of the IL-38 serum levels relationship with patients clinical characteristics showed no correlation with disease onset, stage of depigmentation, and disease activity status.
Conclusions
The lower levels of IL-38 as an anti-inflammatory cytokine support the inflammatory nature of vitiligo. It indicates the difference of IL-38 in sera of vitiligo patients and healthy controls, as the first report of the lower level of this cytokine in the context of vitiligo. The reason of this difference remains to be clarified; as there are not sufficient study reports revealing the role of gender, ethnicity and inflammation on the cytokine network in the context of vitiligo.
... All of them require protease shearing to be active (6,7). Upon binding to the IL-36 functional receptor complex, which consists of the IL-36R and the IL-1 receptor accessory protein (IL-1RAcP), IL-36 agonists activate the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways and then regulate the downstream immune and inflammatory responses (8)(9)(10). IL-36Ra, as a receptor antagonist, hinders dimerization of the IL-36R/IL-1RAcP complex by inhibiting IL-1RAcP recruitment, hence suppressing downstream inflammatory signaling (11). ...
... IL-36 activators bind to the receptor complex formed by IL-36R and IL-1RAcP and then recruit the intracellular signaling molecules myeloid differentiation factor 88 (Myd88), IL-1R-related kinase and tumor necrosis factor receptor-related factor 6 to activate the NF-κB and MAPK signaling pathways (10). This, in turn, promotes the nuclear translocation and activation of activator protein 1 and NF-κB, thereby regulating the transcription and expression of downstream pro-inflammatory genes (8)(9)(10)45). MyD88 is essential for IL-36 signaling. ...
Interleukin (IL)-36 is a member of the IL-1 superfamily, which includes three receptor agonists and one antagonist and exhibits a familial feature of inflammatory regulation. Distributed among various tissues, such as the skin, lung, gut and joints, the mechanism of IL-36 has been most completely investigated in the skin and has been used in clinical treatment of generalized pustular psoriasis. Meanwhile, the role of IL-36 in the intestine has also been under scrutiny and has been shown to be involved in the regulation of various intestinal diseases. Inflammatory bowel disease and colorectal cancer are the most predominant inflammatory and neoplastic diseases of the intestine, and multiple studies have identified a complex role for IL-36 in both of them. Indeed, inhibiting IL-36 signaling is currently regarded as a promising therapeutic approach. Therefore, the present review briefly describes the composition and expression of IL-36 and focuses on the role of IL-36 in intestinal inflammation and colorectal cancer. The targeted therapies that are currently being developed for the IL-36 receptor are also discussed.
... As an anti-inflammatory factor, IL-36Ra can improve asthmatic symptoms by inhibiting the nuclear factor-κB (NF-κB) signalling pathway in murine models [20]. Structurally, IL-36R is a heterodimeric receptor consisting of an IL-1Rrp2 subunit and IL-1 receptor accessory protein (IL-1RAcP) as a co-receptor [21][22][23]. ...
... IL-36α, IL-36β and IL-36γ signalling through IL-36R (IL-1Rrp2) and IL-1 receptor accessory protein (IL-1RAcP) activates NF-κB and mitogen-activated protein kinases (MAPK). In contrast, IL-36Ra binding to IL-36R, with a higher affinity compared with IL-36γ or IL-36α, hinders the recruitment of the co-receptor (IL-1RAcP) and consequently inhibits the corresponding intracellular signalling [21][22][23]. As an anti-inflammatory cytokine, IL-38 binds to IL-1Rrp2 which blocks the (1) IL-36R is a heterodimeric receptor consisting of an IL-1Rrp2 subunit and IL-1RAcP as a co-receptor. ...
Interleukin-38 (IL-38) is the most recent member of the IL-1 family that acts as a natural inflammatory inhibitor by binding to cognate receptors, particularly the IL-36 receptor. In vitro, animal and human studies on autoimmune, metabolic, cardiovascular and allergic diseases, as well sepsis and respiratory viral infections, have shown that IL-38 exerts an anti-inflammatory activity by modulating the generation and function of inflammatory cytokines (e.g. IL-6, IL-8, IL-17 and IL-36) and regulating dendritic cells, M2 macrophages and regulatory T cells (Tregs). Accordingly, IL-38 may possess therapeutic potential for these types of diseases. IL-38 down-regulates CCR3+ eosinophil cells, CRTH2+ Th2 cells, Th17 cells, and innate lymphoid type 2 cells (ILC2), but up-regulates Tregs, and this has influenced the design of immunotherapeutic strategies based on regulatory cells/cytokines for allergic asthma in future studies. In auto-inflammatory diseases, IL-38 alleviates skin inflammation by regulating γδ T cells and limiting the production of IL-17. Due to its ability to suppress IL-1β, IL-6 and IL-36, this cytokine could reduce COVID-19 severity, and might be employed as a therapeutic tool. IL-38 may also influence host immunity and/or the components of the cancer microenvironment, and has been shown to improve the outcome of colorectal cancer, and may participate in tumour progression in lung cancer possibly by modulating CD8 tumour infiltrating T cells and PD-L1 expression. In this review, we first briefly present the biological and immunological functions of IL-38, and then discuss the important roles of IL-38 in various types of diseases, and finally highlight its use in therapeutic strategies.
... The IL-36 subfamily consists of four members, a receptor antagonist (IL-36Ra), and three agonists, IL-36a, IL-36b and, IL-36g (5). These agonists signal through the same receptor (IL-36R) (7) in a MyD88-dependent manner and activate NFkB and MAPK pathways; thus, leading to leukocyte recruitment and amplification of inflammation (8). ...
... However, a few mechanisms in this cytokine biology remain unknown. IL-36g lack of a signal peptide (8,22) suggests it could have access to unconventional secretory pathways (15,27). Our data shows that the addition of LPS/ATP induces IL-36g secretion. ...
Mucosal innate immunity functions as the first line of defense against invading pathogens. Members of the IL-1 family are key cytokines upregulated in the inflamed mucosa. Inflammatory cytokines are regulated by limiting their function and availability through their activation and secretion mechanisms. IL-1 cytokines secretion is affected by the lack of a signal peptide on their sequence, which prevents them from accessing the conventional protein secretion pathway; thus, they use unconventional protein secretion pathways. Here we show in mouse macrophages that LPS/ATP stimulation induces cytokine relocalization to the plasma membrane, and conventional secretion blockade using monensin or Brefeldin A triggers no IL-36γ accumulation within the cell. In silico modeling indicates IL-36γ can pass through both the P2X7R and Gasdermin D pores, and both IL-36γ, P2X7R and Gasdermin D mRNA are upregulated in inflammation; further, experimental blockade of these receptors’ limits IL-36γ release. Our results demonstrate that IL-36γ is secreted mainly by an unconventional pathway through membrane pores formed by P2X7R and Gasdermin D.
... Members of the IL-36 subfamily mediate cellular responses through engagement with the IL-36 receptor complex, comprised of the IL-1RL2 and IL-1RAcP proteins. While the influence of these cytokines in regulating inflammatory responses at barrier sites, such as the skin and the gut, have been established, what influence they may play in regulating metabolic health and disease, particularly in the setting of obesity, has been relatively understudied [2][3][4]. Initial studies, by ourselves and others, have focused on adults with obesity (AWO), whom had established Type 2 diabetes (T2D), to determine whether IL-36 cytokines may play a role in disease. These studies all indicate that serum levels of IL-36 cytokines, specifically IL-36α and γ, are elevated in AWO and may be important mediators of adipose tissue and peripheral inflammation in the context of T2D [5][6][7]. ...
Although the orchestrating role of Interleukin-36 cytokines in regulating inflammation at barrier tissue sites, is well established, whether they play a significant role in the settings of metabolic health and disease, has yet to be fully established. Several recent studies have demonstrated that IL-36 cytokine expression is elevated among adult patients with obesity, and can play roles in regulating both insulin sensitivity and driving inflammation. In this report, we have extended these analyses to paediatric patients and identified an association between elevated serum levels of expression of the specific Interleukin-36 subfamily member, IL-36β, among children with obesity displaying insulin sensitivity, compared to children with obesity who are insulin resistant. While these data further indicate a possible protective role for IL-36 in metabolic health, they also differ with previous findings from an adult patient cohort, where elevated levels of the related cytokine, IL-36γ, were found to occur in association with improved metabolic health. While highlighting important differences between paediatric and adult patient cohorts in the context of metabolic disease associated with obesity, these data underscore the need for a deeper mechanistic analysis of the role of IL-36 cytokines in disease.
... IL-36 cytokines include three agonistic cytokines, IL-36α, IL-36β, and IL-36γ, previously termed IL-1F6, IL-1F8, and IL-1F9, and an antagonist, IL-36Ra, previously named IL-1F5. IL-36 agonistic cytokines are produced by epithelial cells and act on dendritic cells (DCs) to enhance their maturation and cytokine production, playing a key role at the interface between the innate and adaptive immune responses [9,26]. IL-38 binds to the same receptor as IL-36 but exerts antagonist effects and downregulates the Th17 response [10]. ...
IL-1 family members have multiple pleiotropic functions affecting various tissues and cells, including the regulation of the immune response, hematopoietic homeostasis, bone remodeling, neuronal physiology, and synaptic plasticity. Many of these activities are involved in various pathological processes and immunological disorders, including tumor initiation and progression. Indeed, IL-1 family members have been described to contribute to shaping the tumor microenvironment (TME), determining immune evasion and drug resistance, and to sustain tumor aggressiveness and metastasis. This review addresses the role of IL-1 family members in bone sarcomas, particularly the highly metastatic osteosarcoma (OS) and Ewing sarcoma (EWS), and discusses the IL-1-family-related mechanisms that play a role in bone metastasis development. We also consider the therapeutic implications of targeting IL-1 family members, which have been proposed as (i) relevant targets for anti-tumor and anti-metastatic drugs; (ii) immune checkpoints for immune suppression; and (iii) potential antigens for immunotherapy.
... IL-36Ra Deficiency IL-36 family is composed of three agonists (IL-36α, IL-36β, and IL-36γ) and an antagonist (IL-36Ra) [53,54]. IL-36 cytokines are primarily expressed by T cells, keratinocytes, and other cutaneous cells [55]. ...
Recent advances in medical genetics elucidated the background of diseases characterized by superficial dermal and epidermal inflammation with resultant aberrant keratosis. This led to introducing the term autoinflammatory keratinization diseases encompassing entities in which monogenic mutations cause spontaneous activation of the innate immunity and subsequent disruption of the keratinization process. Originally, autoinflammatory keratinization diseases were attributed to pathogenic variants of CARD14 (generalized pustular psoriasis with concomitant psoriasis vulgaris, palmoplantar pustulosis, type V pityriasis rubra pilaris), IL36RN (generalized pustular psoriasis without concomitant psoriasis vulgaris, impetigo herpetiformis, acrodermatitis continua of Hallopeau), NLRP1 (familial forms of keratosis lichenoides chronica), and genes of the mevalonate pathway, i.e., MVK, PMVK, MVD, and FDPS (porokeratosis). Since then, endotypes underlying novel entities matching the concept of autoinflammatory keratinization diseases have been discovered (mutations of JAK1, POMP, and EGFR). This review describes the concept and pathophysiology of autoinflammatory keratinization diseases and outlines the characteristic clinical features of the associated entities. Furthermore, a novel term for NLRP1-associated autoinflammatory disease with epithelial dyskeratosis (NADED) describing the spectrum of autoinflammatory keratinization diseases secondary to NLRP1 mutations is proposed.
... Indeed, encouraging results were observed in the large-scale canakinumab anti-inflammatory thrombosis outcomes study (CANTOS) trial, in which blocking IL-1 improved long-term outcomes following MI (11). Interleukin-36 (IL-36) is a new addition to the IL-1 family sharing structural and functional similarities with IL-1 (12,13). IL-36, consisting of three agonist ligands (IL-36α, IL-36β, and IL-36γ), is emerging as a novel regulator of both innate and adaptive immune responses in various acute and chronic conditions. ...
Aims
Risks and outcomes of myocardial infarction (MI) are different between men and women and some studies have demonstrated that the latter have a higher risk of mortality. Whilst there are many reasons for this, it may also partially be linked to stronger innate and adaptive immune responses mounted by females compared to males. However, little is known about how sex impacts the coronary microvessels, the site where inflammatory processes take place, after an MI. Intravital and laser speckle microscopy was used to image coronary microvessels and ventricular perfusion in vivo in response to myocardial ischaemia-reperfusion (IR) injury in male and female mice. Interleukin-36 (IL-36) is the latest addition to the IL-1 superfamily of pro-inflammatory cytokines and has recently been shown to mediate inflammation in a number of non-cardiovascular diseases. Its role in mediating potential sex-related microcirculatiory pertubations in the heart are unknown. Therefore, the vasculoprotective efficacy of an IL-36 receptor antagonist (IL-36Ra) was also investigated.
Methods and results
Immunostaining and flow cytometry demonstrated higher expression of IL-36 and its receptor in female hearts, an observation confirmed in human samples. Intravital imaging of the anaesthetised mouse beating heart identified significantly greater neutrophil recruitment in female hearts, but a greater burden of thrombotic disease in male hearts. Male mice had reduced functional capillary density and were unable to restore perfusion to baseline values as effectively as females. However, female mice had significantly larger infarcts. Interestingly, IL-36Ra decreased inflammation, improved perfusion, and reduced infarct size in both sexes despite increasing platelet presence in male hearts. Mechanistically, this was explained by IL-36Ra attenuating endothelial oxidative damage and VCAM-1 expression. Importantly, IL-36Ra administration during ischaemia was critical for vasculoprotection to be realised.
Conclusion
This novel study identified notable sex-related differences in the coronary microcirculatory response to myocardial IR injury which may explain why some studies have noted poorer outcomes in women after MI. Whilst contemporary MI treatment focuses on anti-platelet strategies, the heightened presence of neutrophils in female IR injured coronary microvessels necessitates the development of an effective anti-inflammatory approach for treating female patients. We also emphasise the importance of early intervention during the ischaemic period in order to maximise therapeutic effectiveness.
... IL-36 stimulates the production of various cytokines, chemokines, adhesion molecules, and pro-inflammatory mediators. IL-36 cytokines can be induced upon stimulation with different agents including cytokines, TLR ligands, bacterial or viral infections, or other pathological conditions (30,34,35). ...
Type I interferons (IFN) are pro-inflammatory cytokines which can also exert anti-inflammatory effects via the regulation of interleukin (IL)-1 family members. Several studies showed that interferon receptor (IFNAR)-deficient mice develop severe liver damage upon treatment with artificial agonists such as acetaminophen or polyinosinic:polycytidylic acid. In order to investigate if these mechanisms also play a role in an acute viral infection, experiments with the Bunyaviridae family member Rift Valley fever virus (RVFV) were performed. Upon RVFV clone (cl)13 infection, IFNAR-deficient mice develop a severe liver injury as indicated by high activity of serum alanine aminotransferase (ALT) and histological analyses. Infected IFNAR-/- mice expressed high amounts of IL-36γ within the liver, which was not observed in infected wildtype (WT) animals. In line with this, treatment of WT mice with recombinant IL-36γ induced ALT activity. Furthermore, administration of an IL-36 receptor antagonist prior to infection prevented the formation of liver injury in IFNAR-/- mice, indicating that IL-36γ is causative for the observed liver damage. Mice deficient for adaptor molecules of certain pattern recognition receptors indicated that IL-36γ induction was dependent on mitochondrial antiviral-signaling protein and the retinoic acid-inducible gene-I-like receptor. Consequently, cell type-specific IFNAR knockouts revealed that type I IFN signaling in myeloid cells is critical in order to prevent IL-36γ expression and liver injury upon viral infection. Our data demonstrate an anti-inflammatory role of type I IFN in a model for virus-induced hepatitis by preventing the expression of the novel IL-1 family member IL-36γ.
... Individuals with IL-36 RA deficiency seems to being subjected to drug-induced AGEP. However, it is still unclear how IL-36 RA deficiency leads to AGEP (Gabay and Towne, 2015). ...
Drug-induced delayed hypersensitivity reactions (DHRs) is still a clinical and healthcare burden in every country. Increasing reports of DHRs have caught our attention to explore the genetic relationship, especially life-threatening severe cutaneous adverse drug reactions (SCARs), including acute generalized exanthematous pustulosis (AGEP), drug reactions with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). In recent years, many studies have investigated the immune mechanism and genetic markers of DHRs. Besides, several studies have stated the associations between antibiotics-as well as anti-osteoporotic drugs (AOD)-induced SCARs and specific human leukocyte antigens (HLA) alleles. Strong associations between drugs and HLA alleles such as co-trimoxazole-induced DRESS and HLA-B*13:01 (Odds ratio (OR) = 45), dapsone-DRESS and HLA-B*13:01 (OR = 122.1), vancomycin-DRESS and HLA-A*32:01 (OR = 403), clindamycin-DHRs and HLA-B*15:27 (OR = 55.6), and strontium ranelate (SR)-SJS/TEN and HLA-A*33:03 (OR = 25.97) are listed. We summarized the immune mechanism of SCARs, update the latest knowledge of pharmacogenomics of antibiotics- and AOD-induced SCARs, and indicate the potential clinical use of these genetic markers for SCARs prevention in this mini review article.
... IL-36 subsequently activated alveolar and interstitial macrophages, as well as fibroblasts to generate IL-1, CXCL1, GM-CSF, MMPs, and IL-36 ( Fig. 3.10). Our study thus pinpoints IL-36 as a key upstream proinflammatory driver and amplifier of neutrophilic lung inflammation and provides a mechanistic explanation for the link between IL-36 and neutrophilic inflammation that had been observed previously in human diseases and in animal models [115,378,[413][414][415] (Fig. 3.10). Our data therefore provide an experimental rationale for exploring the therapeutic potential of IL-36 signaling blockade to attenuate pro-inflammatory events in human lung disease with a significant contribution of neutrophils, such as asthma and COPD. ...
... Interleukin (IL)-36 belongs to the IL-1 pro-inflammatory cytokine family and includes three pro-inflammatory agonists, IL-36α, IL-36β and IL-36γ, and an IL-36 receptor (IL-36R) antagonist [1][2][3]. The IL-36 signalling pathway is associated with the pathogenesis of several inflammatory diseases, including dermatological disorders such as generalized pustular psoriasis (GPP), palmoplantar pustulosis, allergic contact dermatitis, atopic dermatitis and hidradenitis suppurativa, in addition to inflammatory bowel disease [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. ...
Background and objective:
The interleukin-36 signalling pathway is associated with pathogenesis of a number of inflammatory diseases. Spesolimab is a selective, humanised, IgG1 antibody that targets the interleukin-36 receptor. We aimed to evaluate the pharmacokinetics, safety and tolerability of single and multiple doses of spesolimab in healthy non-Japanese and Japanese subjects.
Methods:
Five phase I clinical studies (three placebo-controlled dose-escalation, two open-label) were conducted in healthy volunteers; single or multiple doses of spesolimab were administered by intravenous infusion or subcutaneous injection. Plasma samples were collected to investigate the pharmacokinetics of spesolimab and evaluate changes with respect to dose, frequency of dosing, formulation and injection site. Immunogenicity, safety and tolerability were also assessed.
Results:
Intravenous spesolimab exhibited target-mediated drug disposition at low doses (0.01-0.3 mg/kg) and linear kinetics at doses ≥ 0.3 mg/kg. Steady state was not attained after the fourth weekly dose because of the long half-life (3-5 weeks). Bioavailability of subcutaneous spesolimab increased with increasing dose over the range of 150-600 mg and was higher when administered to the thigh than to the abdomen. The pharmacokinetic profile was consistent between Japanese and non-Japanese subjects. Positive anti-drug antibody responses occurred during the terminal phase of the spesolimab concentration-time profile in 26.7-33.3% and 16.7-37.5% of subjects receiving intravenous and subcutaneous spesolimab, respectively. The impact of anti-drug antibodies on spesolimab pharmacokinetics was low in healthy volunteers, with the impact on spesolimab plasma concentrations only observed in a few subjects at higher titres (≥ 11,400). No serious adverse events were reported; intravenous doses up to 1200 mg were well tolerated in healthy volunteers.
Conclusions:
The pharmacokinetic profile and safety data obtained from these phase I clinical studies have been used to guide spesolimab dosing in clinical studies of patients with interleukin-36-mediated diseases.
Clinical trial registration:
For Studies 1-5, NCT02525679, NCT02852824, NCT03100903, NCT03123094, NCT03617835.
... As a result, IL-36 has been linked to a variety of inflammatory disorders, including psoriasis, arthritis, inflammatory bowel disease, joint disease, pulmonary and renal injuries, and even cancer. [15]. ...
Background: IBD (Inflammatory bowel disease) is a chronic inflammatory condition that affects the intestines., in which cytokines are thought to have a role in the etiology and pathophysiology. IBD is divided into two types: Ulcerative Colitis (UC), and Crohn's Disease (CD). Aim of the study: The current study examined the level of, IL-36 in the blood of sixty IBD Iraqi patients (30 CD, 30 UC, and 30 HC). The concentrations were correlated with Age, age at onset, body mass index (BMI), cigarette-smoking status, disease duration, gender, symptoms, and extra-intestinal features. Result: The findings revealed that IL-36 level for UC & CD patients have been significantly higher than the healthy control). However, there was a significant difference in IL-36 levels between UC and CD patients p. When UC and CD patients were divided into subgroups based on certain features, it was discovered that IL-36 was significantly increased in CD patients with disease duration >10 year compared to UC patients). In addition, It was in BMI underweight, CD patients significantly increased compared, to UC patient. while in CD patient there was a significant difference between patients with BMI underweight compared to patients with BMI obese). In the case of, non-smoker patients there was a significant increase in CD patients compared to UC). Conclusion: the findings suggest that IL-36 has a role in the etiology & pathophysiology of IBD. Keywords: IBD, CD, UC, HC, IL-36, Disease duration, Body mass index, cigarette-Smoking, healthy control, Crohn's Disease, Ulcerative Colitis, and Inflammatory Bowel Disease.
... The IL-36 cytokine family is crucial for immune homeostasis and inflammation response through the regulation of the production of pro-inflammatory and anti-inflammatory cytokines (10)(11)(12). IL-36 cytokines can be secreted by different types of cells, including keratinocytes (13), macrophages (14), epithelial cells (15), T cells (16,17), myofibroblasts (18), neutrophils (19), and plasma cells (20). Importantly, IL-36 cytokines contribute to the pathogenesis of autoimmune and inflammatory diseases, such as psoriasis, pulmonary diseases, inflammatory bowel disease, rheumatoid arthritis, allergic rhinitis, Sjogren's syndrome, and systemic lupus erythematosus (15)(16)(17)(20)(21)(22). ...
Interleukin (IL)-36 cytokines are members of the IL-1 superfamily, which consists of three agonists (IL-36α, IL-36β and IL-36γ) and an IL-36 receptor antagonist (IL-36Ra). IL-36 cytokines are crucial for immune and inflammatory responses. Abnormal levels of IL-36 cytokine expression are involved in the pathogenesis of inflammation, autoimmunity, allergy and cancer. The present study provides a summary of recent reports on IL-36 cytokines that participate in the pathogenesis of inflammatory diseases, and the potential mechanisms underlying their roles in asthma. Abnormal levels of IL-36 cytokines are associated with the pathogenesis of different types of asthma through the regulation of the functions of different types of cells. Considering the important role of IL-36 cytokines in asthma, these may become a potential therapeutic target for asthma treatment. However, existing evidence is insufficient to fully elucidate the specific mechanism underlying the action of IL-36 cytokines during the pathological process of asthma. The possible mechanisms and functions of IL-36 cytokines in different types of asthma require further studies.
... IL-36 cytokines are secreted by immune and nonimmune cells including fibroblasts, epithelial cells, neural cells, keratinocytes, DCs, and MΦs. Those cells which express IL-36 cytokines and belong to innate and adaptive immune systems trigger different cytokines, such as proinflammatory cytokines which result in proliferation of T h1 and polarization of T h17 [248,250,253,254]. Moreover, IL-36 contributes to skin immunopathological features, e.g., psoriasis and fungal respiratory immunopathological conditions caused by Aspergillus fumigatus and kidney diseases. ...
Interleukins (ILs)-which are important members of cytokines-consist of a vast group of molecules, including a wide range of immune mediators that contribute to the immunological responses of many cells and tissues. ILs are immune-glycoproteins, which directly contribute to the growth, activation, adhesion, differentiation, migration, proliferation, and maturation of immune cells; and subsequently, they are involved in the pro and anti-inflammatory responses of the body, by their interaction with a wide range of receptors. Due to the importance of immune system in different organisms, the genes belonging to immune elements, such as ILs, have been studied vigorously. The results of recent investigations showed that the genes pertaining to the immune system undergo progressive evolution with a constant rate. The occurrence of any mutation or polymorphism in IL genes may result in substantial changes in their biology and function and may be associated with a wide range of diseases and disorders. Among these abnormalities, single nucleotide polymorphisms (SNPs) can represent as important disruptive factors. The present review aims at concisely summarizing the current knowledge available on the occurrence, properties, role, and biological consequences of SNPs within the IL-1 family members.
... Indeed, the large-scale canakinumab antiinflammatory thrombosis outcomes study (CANTOS) trial provided exciting evidence that targeting this cytokine was beneficial in improving long-term outcomes post-MI in the absence of lipid lowering (17). In the last decade, genes encoding a novel cytokine cluster, namely interleukin-36 (IL-36), with structural and functional similarities to IL-1, were discovered (18,19). IL-36, a collective name for 3 agonist ligands, IL-36α, IL-36β, and IL-36γ (previously called IL-1F6, IL-1F8, and IL-1F9), is fast emerging as a novel player regulating both innate and adaptive immune responses in a number of acute and chronic disorders. ...
Following myocardial infarction (MI), elderly patients have a poorer prognosis which may belinked to increased coronary microvessel susceptibility to injury. Interleukin-36 (IL-36), anewly discovered pro-inflammatory member of the IL-1 superfamily, may mediate this injurybut its role in the injured heart is currently not known. We firstly demonstrated the presence of IL-36(α/β) and its receptor (IL-36R) in ischaemia-reperfusion (IR) injured mouse hearts and,interestingly, noted that expression of both increased with ageing. An intravital modelfor imaging the adult and aged IR injured beating heart in real-time in vivo was used todemonstrate heightened basal and injury-induced neutrophil recruitment, and poorer bloodflow, in the aged coronary microcirculation when compared to adult hearts. An IL-36Rantagonist (IL-36Ra) significantly decreased neutrophil recruitment, improved blood flow andreduced infarct size in both adult and aged mice. This may be mechanistically explained byattenuated endothelial oxidative damage and VCAM-1 expression in IL-36Ra treated mice.Our findings of an enhanced age-related coronary microcirculatory dysfunction inreperfused hearts may explain the poorer outcomes in elderly patients following MI. Sincetargeting the IL-36/IL-36R pathway was vasculoprotective in aged hearts, it may potentially be a therapy for treating MI in the elderly.
... In this mechanism, keratinocytes have been thought as a responder of inflammatory mediators released by DCs and/or IL-17-producing cells [35]. Mechanically, in lesional skin, activated mDCs by IL-36 produce high amount of IL-1β, IL-6 and IL-23 via unclear mechanisms [36][37][38]. IL-1β and IL-23 drive human naive CD4 + T cells differentiation into Th17 cell [39], while IL-6, together with TGFβ, promotes murine naive CD4 + T cells development into Th17 cell [40], and then IL-23 activates Th17 cells to produce IL-17A, IL-17F, IL-22 and other cytokines [17,18,[41][42][43]. Among these cytokines, IL-17 cytokines induce keratinocytes or other innate immune cells to produce a plethora of cytokines [44][45][46], chemokines [47] and AMPs [25,48,49] to promote the expansion of Th17 cells, γδT cells and group 3 innate lymphoid cells (ILC3) or recruit neutrophils and more IL-17-producing T cells into sites of inflammation in the skin [26,[50][51][52][53] (Figure 1). ...
Cutaneous homeostasis is maintained by dynamic cellular communications between different cell types in the skin through interactions with various mediators, including cytokines, chemokines and antimicrobial peptides/proteins (AMPs). Keratinocytes, as the major cell type of the epidermis, not only form a passive physical barrier, but also actively participate in the pathogenesis of many, if not all, inflammatory skin diseases. Keratinocytes highly interact with immune cells to shape, amplify or regulate inflammatory responses, thus triggering and/or sustaining these inflammatory skin diseases. In this review, crosstalk between keratinocytes and immune cells is summarized, and its contributions to two major inflammatory skin disorders including psoriasis and atopic dermatitis are highlighted.
... It is well known that proinflammatory factors, such as IL-1, IL-17, and TNF, play an important role in the pathogenesis of MS and EAE [40][41][42]. IL-36α, IL-36β, and IL-36γ are members of the IL-1 family that signal through a common receptor composed of IL-36 receptor (IL-36R) and IL-1R accessory protein (IL-1RAcP) to activate NF-κB and MAPKs and produce proinflammatory molecules such as IL-1a/b, IL-6, and IL-8 [43]. Interleukin-17A (IL-17A) is a founding member of a novel family of inflammatory cytokines [44], and inhibition of IL-17-induced NOTCH1 activation can attenuate EAE [40]. ...
Objective. To study the protective effect of fecal microbiota transplantation (FMT) on experimental autoimmune encephalomyelitis (EAE) and reveal its potential intestinal microflora-dependent mechanism through analyses of the intestinal microbiota and spinal cord transcriptome in mice. Method. We measured the severity of disease by clinical EAE scores and H&E staining. Gut microbiota alteration in the gut and differentially expressed genes (DEGs) in the spinal cord were analyzed through 16S rRNA and transcriptome sequencing. Finally, we analyzed associations between the relative abundance of intestinal microbiota constituents and DEGs. Results. We observed that clinical EAE scores were lower in the EAE+FMT group than in the EAE group. Meanwhile, mice in the EAE+FMT group also had a lower number of infiltrating cells. The results of 16S rRNA sequence analysis showed that FMT increased the relative abundance of Firmicutes and Proteobacteria and reduced the abundance of Bacteroides and Actinobacteria. Meanwhile, FMT could modulate gut microbiota balance, especially via increasing the relative abundance of g_Adlercreutzia, g_Sutterella, g_Prevotella_9, and g_Tyzzerella_3 and decreasing the relative abundance of g_Turicibacter. Next, we analyzed the transcriptome of mouse spinal cord tissue and found that 1476 genes were differentially expressed between the EAE and FMT groups. The analysis of these genes showed that FMT mainly participated in the inflammatory response. Correlation analysis between gut microbes and transcriptome revealed that the relative abundance of Adlercreutzia was correlated with the expression of inflammation-related genes negatively, including Casp6, IL1RL2 (IL-36R), IL-17RA, TNF, CCL3, CCR5, and CCL8, and correlated with the expression of neuroprotection-related genes positively, including Snap25, Edil3, Nrn1, Cpeb3, and Gpr37. Conclusion. Altogether, FMT may selectively regulate gene expression to improve inflammation and maintain the stability of the intestinal environment in a gut microbiota-dependent manner.
1. Introduction
Multiple sclerosis (MS) is a chronic inflammatory disease characterized by astroglial injury, axonal loss, demyelination, and inflammation in the brain and spinal cord [1]. The pathogenesis of MS is still unclear, but the general hypothesis is that autoimmunity, viral infection (e.g., Epstein-Barr virus (EBV)), genetic tendency, environmental factors, and individual susceptibility factors play a comprehensive role in the etiology of MS [2, 3]. Moreover, dysbiosis of the commensal gut microbiota is commonly observed in MS patients and might play a pathological role in the inception and progression of this disease [4]. Studies have linked gut dysbiosis to inflammatory bowel disease, local and systemic inflammation, hypertension, type 2 diabetes, and MS [5, 6]. Therefore, modulating the microbiota to correct ecological imbalance may be a new practice to treat MS.
FMT is the transplantation of a fecal microbiota suspension from a healthy donor to a recipient, with the aim of treating or preventing disease via manipulation of the microbiome [7]. Some studies have shown that FMT may be a promising therapy option for nervous system diseases, including MS [8, 9]. It is likely that some elements of donor’s healthy gut microbiota can induce rapid production of anti-inflammatory mediators that may counteract proinflammatory cytokines [10]. Notably, fecal transplants from MS patients into germ-free mice have been found to result in more serious symptoms of experimental autoimmune encephalomyelitis (EAE) and reduce the proportions of IL-10⁺ Tregs [11]. Interestingly, gavage with the human gut-derived commensal strain Prevotella histicola has been found to bring about a dropped incidence of disease in MS mouse model. The mechanism may be a rebalance between proinflammatory response (including Th1 and 17 cells) and anti-inflammatory response (including Treg cells) [12]. These findings suggest that FMT may exert a therapeutic effect on MS patients by reshaping the intestinal flora and attenuating inflammatory responses.
In this study, we used an EAE mouse model to help develop new therapies for MS and to identify the role of intestinal microflora in coordinating the possible mechanism of FMT on MS. Subsequently, we investigated the relationship between spinal cord transcriptome and intestinal microbiota in the context of inflammation and analyzed the therapeutic effect of FMT on EAE mice. Our discoveries will provide unique insights into the mechanism of intestinal microbiome therapy for MS.
2. Materials and Methods
2.1. Animals
Female C57BL/6 mice (specific pathogen-free grade), 6-8 weeks of age and weighing 18-20 g (Ji’nan Pengyue Laboratory Animal Breeding Co., Ltd., Jinan, China), were used in the study. These mice were randomly divided into control, EAE, and EAE+FMT groups according to these experimental designs of Wang et al. and Wen et al [13, 14]. All groups of mice were raised under standard humidity, temperature, and a normal diet from day 0 to day 19. All animal studies were conducted in compliance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and carried out according to protocols approved by the Institutional Animal Care and Use Committee of Binzhou Medical University Hospital.
2.2. Induction of EAE and Assessment of Clinical Signs
EAE was induced as mentioned previously [15]. Concisely, C57BL/6 mice were injected with 200 μg (MOG) 35-55 peptide (GenScript, New Jersey, USA) emulsified in 100 μg of complete Freund’s adjuvant (CFA, Sigma-Aldrich, Missouri, USA) and an additional 400 μg heat-inactivated mycobacterium tuberculosis (Difco, Michigan, USA) by subcutaneous injection. In addition, 300 ng of pertussis toxin (PTX, Merck Millipore, Massachusetts, USA) was injected intraperitoneally on the day of immunization and 48 hours later. Clinical signs were observed and recorded daily by 2 researchers as follows: 0, normal; 1, paralysis or staggering of the tail; 2, mild paralysis of two hind limbs or severe paralysis of one hind limb; 3, severe paralysis of both hind limbs; 4, two hind limbs were severely paralyzed and the forelimbs were affected; 5, moribund or death; and 0.5, intermediate clinical sign (Table 1).
Clinical score
Normal
0
For intermediate clinical sign
0.5
Paralysis or staggering of the tail
1
Mild paralysis of two hind limbs or severe paralysis of one hind limb
2
Severe paralysis of both hind limbs
3
Two hind limbs were severely paralyzed and the forelimbs were affected
4
Moribund or death
5
... IL-36g is constitutively expressed at low levels by keratinocytes, and strongly upregulated following activation (15,16). The IL-36 cytokines are not constitutively expressed by other cell types present in skin but are inducible in myeloid cells following activation (17). In addition to functioning as cytokines, IL-1a, IL-33 and some isoforms of IL-37 are known to translocate to the nucleus where they can regulate gene expression through their DNA-binding capabilities (8,13,18). ...
The skin barrier would not function without IL-1 family members, but their physiological role in the immunological aspects of skin barrier function are often overlooked. This review summarises the role of IL-1 family cytokines (IL-1α, IL-1β, IL-1Ra, IL-18, IL-33, IL-36α, IL-36β, IL-36γ, IL-36Ra, IL-37 and IL-38) in the skin. We focus on novel aspects of their interaction with commensals and pathogens, the important impact of proteases on cytokine activity, on healing responses and inflammation limiting mechanisms. We discuss IL-1 family cytokines in the context of IL-4/IL-13 and IL-23/IL-17 axis-driven diseases and highlight consequences of human loss/gain of function mutations in activating or inhibitory pathway molecules. This review highlights recent findings that emphasize the importance of IL-1 family cytokines in both physiological and pathological cutaneous inflammation and emergent translational therapeutics that are helping further elucidate these cytokines.
... Mutations in the IL-36RN gene can result in uncontrolled IL-36 signaling and increase the downstream production of further proinflammatory cytokines and chemokines. 10 However, it is still unclear if mutations in IL-36RN lead to AGEP or, rather, to a drug-induced generalized pustular psoriasis (GPP), as it is described in some cases. 11 AGEP has been classified as a T cell-related sterile neutrophilic inflammatory response (type IVd reaction). ...
Background: Pustular psoriasis and Acute Generalized Exanthematous Pustulosis (AGEP) are grouped under pustular diseases, in which their clinical manifestations are similar. Those diseases can lead to exfoliative dermatitis. Purpose:To evaluate a specific histopathological examination in differentiating Pustular Psoriasis and AGEP. Case: A 55-year-old woman presented with sudden redness and diffused scaly skin with multiple pustules and also fever. She had taken Cefadroxil 2 days before the scales and pustules appeared. Leukocytosis and histopathological examination results from biopsy supported the diagnosis of AGEP. The patient was then hospitalized and received steroid therapy. Within the first week of tapering off, the scales disappeared but the pustules increased. After such clinical findings, the histopathological examination results were revisited and reassessed. Thus, we considered changing the diagnosis to Pustular Psoriasis, and the therapy was switched to Methotrexate. The patient had a better outcome, and the pustules slowly disappeared entirely. Discussion: It is often difficult to differentiate between the pustules in pustular psoriasis and AGEP unless by thorough history-taking and physical examinations. AGEP is characterized by a widespread of pustules with an acute febrile onset; while pustular psoriasis is an acute variant of psoriasis where pustules are spread over erythematous skin and accompanied by high fever and leukocytosis. Conclusion: Histopathological examination is the gold standard for the establishment of pustular psoriasis diagnosis. The histopathological characteristics of pustular psoriasis and AGEP are difficult to differentiate. Therefore, we need detailed history-taking and physical examination to establish the diagnosis.
The interleukin (IL)‐1 superfamily upregulates immune responses and maintains homeostasis between the innate and adaptive immune systems. Within the IL‐1 superfamily, IL‐36 plays a pivotal role in both innate and adaptive immune responses. Of the four IL‐36 isoforms, three have agonist activity (IL‐36α, IL‐36β, IL‐36γ) and the fourth has antagonist activity (IL‐36 receptor antagonist [IL‐36Ra]). All IL‐36 isoforms bind to the IL‐36 receptor (IL‐36R). Binding of IL‐36α/β/γ to the IL‐36R recruits the IL‐1 receptor accessory protein (IL‐1RAcP) and activates downstream signalling pathways mediated by nuclear transcription factor kappa B and mitogen‐activated protein kinase signalling pathways. Antagonist binding of IL‐36Ra to IL‐36R inhibits recruitment of IL‐1RAcP, blocking downstream signalling pathways. Changes in the balance within the IL‐36 cytokine family can lead to uncontrolled inflammatory responses throughout the body. As such, IL‐36 has been implicated in numerous inflammatory diseases, notably a type of pustular psoriasis called generalized pustular psoriasis (GPP), a chronic, rare, potentially life‐threatening, multisystemic skin disease characterised by recurrent fever and extensive sterile pustules. In GPP, IL‐36 is central to disease pathogenesis, and the prevention of IL‐36‐mediated signalling can improve clinical outcomes. In this review, we summarize the literature describing the biological functions of the IL‐36 pathway. We also consider the evidence for uncontrolled activation of the IL‐36 pathway in a wide range of skin (e.g., plaque psoriasis, pustular psoriasis, hidradenitis suppurativa, acne, Netherton syndrome, atopic dermatitis and pyoderma gangrenosum), lung (e.g., idiopathic pulmonary fibrosis), gut (e.g., intestinal fibrosis, inflammatory bowel disease and Hirschsprung's disease), kidney (e.g., renal tubulointerstitial lesions) and infectious diseases caused by a variety of pathogens (e.g., COVID‐19; Mycobacterium tuberculosis , Pseudomonas aeruginosa , Streptococcus pneumoniae infections), as well as in cancer. We also consider how targeting the IL‐36 signalling pathway could be used in treating inflammatory disease states.
Tissue-specific mechanisms regulate neutrophil immunity at the oral barrier, which plays a key role in periodontitis. Although it has been proposed that fibroblasts emit a powerful neutrophil chemotactic signal, how this chemotactic signal is driven has not been clear. The objective of this study was to investigate the site-specific regulatory mechanisms by which fibroblasts drive powerful neutrophil chemotactic signals within the oral barrier, with particular emphasis on the role of the IL-36 family. The present study found that IL-36γ, agonist of IL-36R, could promote neutrophil chemotaxis via fibroblast. Single-cell RNA sequencing data disclosed that IL36G is primarily expressed in human and mouse gingival epithelial cells and mouse neutrophils. Notably, there was a substantial increase in IL-36γ levels during periodontitis. In vitro experiments demonstrated that IL-36γ specifically activates gingival fibroblasts, leading to chemotaxis of neutrophils. In vivo experiments revealed that IL-36Ra inhibited the infiltration of neutrophils and bone resorption, while IL-36γ promoted their progression in the ligature-induced periodontitis mouse model. In summary, these data elucidate the function of the site-enriched IL-36γ in regulating neutrophil immunity and bone resorption at the oral barrier. These findings provide new insights into the tissue-specific pathophysiology of periodontitis and offer a promising avenue for prevention and treatment through targeted intervention of the IL-36 family.
Crimean–Congo hemorrhagic fever (CCHF) is a severe viral disease. The scientific literature is growing, emphasizing the significance of the interleukin (IL)‐36 family in the proinflammatory signaling pathway. However, to date, no research has explored the potential of IL‐36 family members as biomarkers in CCHF. This study aims to bridge this gap by evaluating IL‐36α, IL‐36β, and IL‐36γ levels in CCHF patients and healthy controls and investigating their association with disease severity and prognosis. Sixty confirmed CCHF patients and 29 healthy controls were enrolled in this case‐control study. Serum levels of IL‐36α, IL‐36β, and IL‐36γ were measured using enzyme‐linked immunosorbent assays. Significantly higher levels of IL‐36α and IL‐36β were observed in CCHF patients compared to healthy controls ( p < 0.05). However, no statistically significant changes were found in IL‐36γ levels between the two groups. Among the CCHF patients, those who did not survive exhibited significantly elevated IL‐36α and IL‐36γ levels compared to survivors ( p < 0.01). Positive correlations were identified between IL‐36α and IL‐36γ levels with activated partial thromboplastin time, and D‐dimer ( p < 0.01). Conversely, platelet levels showed a negative correlation with IL‐36α and IL‐36γ levels ( p < 0.01). The increased levels of IL‐36α, IL‐36β, and IL‐36γ in patients indicate their participation in proinflammatory reactions in CCHF patients. Understanding the role of IL‐36 family members in CCHF pathogenesis could offer valuable insights into disease progression and facilitate the development of targeted therapeutic strategies.
Insulin resistance, i.e., decreased biological response to insulin, is a risk factor for many diseases, such as obesity, type 2 diabetes (T2DM), cardiovascular disease, polycystic ovary syndrome, some forms of cancer and neurodegenerative diseases. One of its main causes is chronic low-grade inflammation, mediated by the proinflammatory pathways, such as the c-Jun N-terminal kinase (JNK) pathway and the nuclear factor kappa B (NFκB) pathway. Interleukin (IL)-38 (IL-38) is a newly discovered cytokine that belongs to the IL-1 family. There are three hypothetical pathways through which IL-38 may bind to the specific receptors and inhibit their proinflammatory activity. Those pathways are associated with IL-36 receptor (IL-36R), IL-1 receptor accessory protein-like 1 (IL1RAPL1) and IL-1 receptor 1 (IL1R1). There are studies linking IL-38 to improve insulin sensitivity through the difference in serum IL-38 in patients with insulin resistance or the correlation of IL-38 concentrations with insulin resistance indexes. However, many questions still remain regarding the biological activity of IL-38 itself and its role in the pathogenesis of insulin resistance. The goal of this study is to showcase IL-38, its biological activity, hypothesized signaling pathways, connection with insulin resistance and future perspectives of research on IL-38. We present that IL-38 associated signaling can be a potential target for the treatment of insulin resistance and associated diseases.
Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) is a tick-borne, biosafety level 4 pathogen that often causes a severe hemorrhagic disease in humans (CCHF) with high case fatality rates. The virus is believed to be maintained in a tick-vertebrate-tick ecological cycle involving numerous wild and domestic animal species, however the biology of CCHFV infection in these animals remains poorly understood. Here, we challenge domestic sheep with CCHFV Kosovo Hoti, a highly pathogenic clinical isolate increasingly utilized in current research. In the absence of prominent clinical signs, the infection leads to an acute viremia and coinciding viral shedding, high fever and markers for potential impairment in liver and kidney functions. A number of host responses distinguish the subclinical infection in sheep versus fatal infection in humans. These include an early reduction of neutrophil recruitment and its chemoattractant, IL-8, in the blood stream of infected sheep, whereas neutrophil infiltration and elevated IL-8 are features of fatal CCHFV infections reported in immunodeficient mice and humans. Several inflammatory cytokines that correlate with poor disease outcomes in humans and have potential to cause vascular dysfunction, a primary hallmark of severe CCHF, are down-regulated or restricted from increasing in sheep. Of particular interest, the detection of CCHFV RNA in a variety of sheep tissues long after the acute phase of infection indicates a widespread viral dissemination in the host and suggests a potentially long-term persisting impact of CCHFV infection. Consistent with this, antibody responses exhibit features reminiscent of recurring antigenic boost, and a prolonged fever or late fever spike correlates with high levels of viral RNA persistence. These findings reveal previously unrecognized aspects of CCHFV biology in animals and highlight the need for extended experimental infection studies.
Author summary
Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) is a tick-borne virus with potential to cause a fatal hemorrhagic disease in humans. Many wild and domestic animals such as sheep are believed to serve as intermediate hosts that amplify and transmit the virus without developing overt disease. However, the biology of CCHFV infection in animals remains to be better understood through new experimental infection research. Here, we characterize the infection of sheep with a highly pathogenic (to humans) CCHFV clinical isolate. This work confirms early studies indicating that CCHFV infection in animals does not lead to prominent signs of disease despite a short period of viral accumulation in the blood. Importantly, we identify host responses that distinguish the lack of disease in sheep versus the fatal disease in humans. Sheep are able to restrict several immune factors that potentially play a damaging role toward poor disease outcomes. Furthermore, we provide pioneering findings of widespread CCHFV dissemination and persistent presence of CCHFV genetic material in tissues of animal hosts that do not develop major disease. These new data are anticipated to inform medical countermeasure development and guide public health measures, with considerations of potential long-term impact of CCHFV on human and animal health.
Background:
The objective of this study was to compare the levels of gingival crevicular fluid (GCF), salivary, and serum matrix metalloproteinase-9, interleukin (IL)-17, IL-36γ, and IL-38 in individuals with healthy periodontium, gingivitis, and periodontitis and to evaluate their correlations with clinical periodontal parameters.
Materials and methods:
Ninety systemically healthy and nonsmoking volunteers divided into a healthy (H) group (n = 30), a gingivitis (G) group (n = 30), and a periodontitis (P) group (n = 30) were included in this study. Clinical periodontal parameters of volunteers were recorded, and GCF, unstimulated saliva, and serum samples were collected. Data analysis was done with enzyme-linked immunosorbent assays. The Kruskal-Wallis test and Bonferroni correction were used for multiple comparisons and post hoc statistical analyses.
Results:
The group H had significantly lower clinical parameters than the group P (p < 0.001). GCF and salivary IL-36γ and IL-38 levels were significantly higher in the group P than in the H and G groups (p < 0.05). Positive correlations between biochemical findings and clinical periodontal parameters were observed.
Conclusions:
IL-36γ and IL-38 levels in GCF, saliva, and serum correlate with clinical periodontal parameters and may play a role in determining the activity of periodontitis.
Pustular psoriasis is characterised by eruptions of neutrophilic sterile pustules. The European Rare and Severe Psoriasis Expert Network consensus defines pustular psoriasis into three subtypes; generalised pustular psoriasis (GPP), palmoplantar pustulosis and acrodermatitis continua of Hallopeau (ACH). Mixed forms are categorised according to their predominant features. However, the Japanese Dermatological Association includes ACH under the diagnosis of GPP. This article aims to review the similarities and differences between ACH and GPP. Based on our review, interleukin (IL)-36RN mutations, the most frequent genetic findings in pustular psoriasis are found most commonly in GPP, followed by ACH. Genotypes of IL-36RN mutations among GPP patients and ACH patients are different between European and Asian ethnicities. IL-36 signalling pathway is the main mechanism. Metabolic diseases are common comorbidities and joint involvement can occur in 20.5%-36.4% of both conditions. Associated plaque psoriasis is more common in GPP than in ACH. Generally, ACH, even the generalised type, does not have systemic inflammation whereas GPP can occur with or without systemic inflammation. ACH can occur before, simultaneously, or after the development of GPP. However, response to treatment for GPP and ACH even in the same patients appear to be different. ACH seemed to be more recalcitrant to treatment than GPP but severe flare of GPP can lead to morbidity and mortality. Although GPP and ACH share genotypes and pathogenesis, we believe that ACH should be classified separately from GPP, and not under diagnosis of GPP. Future research is warranted to satisfactorily distinguish the two conditions.
Acute generalized exanthematous pustulosis (AGEP), an uncommon severe cutaneous adverse reaction, is believed to be a T cell-mediated hypersensitivity reaction, of which the most common cause is medication. However, infections have also been reported to be associated with AGEP. Here, we present a case of AGEP possibly related with Staphylococcus pettenkoferi.
Interleukin (IL)-36 cytokines are members of the IL-1 superfamily of cytokines. IL-36 cytokines are composed of three agonists (IL-36α, IL-36β, and IL-36γ) and two antagonists (IL-36 receptor antagonist [IL36Ra] and IL-38). These work in innate and acquired immunity and are known to contribute to host defense and to the pathogenesis of autoinflammatory diseases, autoimmune diseases, and infectious diseases. In the skin, IL-36α and IL-36γ are mainly expressed by keratinocytes in the epidermis, although they are also produced by dendritic cells, macrophages, endothelial cells, and dermal fibroblasts. IL-36 cytokines participate in the first-line defense of the skin against various exogenous assaults. IL-36 cytokines play significant roles in the host defense system and in the regulation of inflammatory pathways in the skin, collaborating with other cytokines/chemokines and immune-related molecules. Thus, numerous studies have shown IL-36 cytokines to play important roles in the pathogenesis of various skin diseases. In this context, the clinical efficacy and safety profiles of anti-IL-36 agents such as spesolimab and imsidolimab have been evaluated in patients with generalized pustular psoriasis, palmoplantar pustulosis, hidradenitis suppurativa, acne/acneiform eruptions, ichthyoses, and atopic dermatitis. This article comprehensively summarizes the roles played by IL-36 cytokines in the pathogenesis and pathophysiology of various skin diseases and summarizes the current state of research on therapeutic agents that target IL-36 cytokine pathways.
Psoriasis is a recurrent inflammatory skin disease. IL-36-related cytokines are overexpressed in psoriasis, but the mechanism is not yet clear. Costunolide (Cos) is a sesquiterpenoid compound derived from the root of the traditional Chinese medicine Aucklandia lappa Decne. This study aimed to explore the mechanism of Cos on improving psoriasis-like skin inflammation. An in vivo model was established by applying imiquimod treatment to the back skin of mice, and an in vitro model was established by using polyinosinic-polycytidylic acid (Poly(I:C)) stimulated-mouse primary dermal fibroblasts to induce inflammation. The results showed that Cos improved the pathological changes of psoriasis-like skin inflammation. In addition, Cos could inhibit epidermal damage and inflammation-related expression and improve the occurrence of skin-related inflammation in both in vivo and in vitro experiments. The improvement of psoriasis-like skin inflammatory response might be through the P2X7R/IL-36 signaling pathway. Collectively, Cos has an inhibitory effect on the expression of psoriasis-like skin inflammation. This showed that Cos has potential skin health promoting benefits by preventing psoriasis-like skin inflammation.
Inflammatory factors, such as the IL-1 family, are generally acknowledged to be involved in systemic diseases and IL-1α and IL-1β, in particular, have been linked to cardiovascular disease with IL-18, IL-33, IL-36, IL-37 and IL-38 yet to be explored. The current review aims to summarize mechanisms of IL-18, IL-33, IL-36, IL-37 and IL-38 in myocardial infarction, hypertension, arrhythmia, valvular disease and aneurysm and to explore the potential for cardiovascular disease treatment strategies and discuss future directions for prevention and treatment.
Background:
The interleukin (IL)-36 cytokines are a sub-family of the IL-1 family which are becoming increasingly implicated in the pathogenesis of inflammatory diseases and malignancies. Initial studies of IL-36 signalling in tumorigenesis identified an immune-mediated anti-tumorigenic function for these cytokines. However, more recent studies have shown IL-36 cytokines also contribute to the pathogenesis of lung and colorectal cancer (CRC).
Methods:
The aim of this study was to investigate IL-36 expression in CRC using transcriptomic datasets and software such as several R packages, Cytoscape, GEO2R and AnalyzeR. Validation of results was completed by qRT-PCR on both cell lines and a patient cohort. Cellular proliferation was assessed by flow cytometry and resazurin reduction.
Results:
We demonstrate that IL-36 gene expression increases with CRC development. Decreased tumoral IL-36 receptor expression was shown to be associated with improved patient outcome. Our differential gene expression analysis revealed a novel role for the IL-36/IL-17/IL-23 axis, with these findings validated using patient-derived samples and cell lines. IL-36γ, together with either IL-17a or IL-22, was able to synergistically induce different genes involved in the IL-17/IL-23 axis in CRC cells and additively induce colon cancer cell proliferation.
Conclusions:
Collectively, this data support a pro-tumorigenic role for IL-36 signalling in colon cancer, with the IL-17/IL-23 axis influential in IL-36-mediated colon tumorigenesis.
Spinal cord injury (SCI) is a serious injury to the central nervous system that causes significant physical and psychological trauma to the patient. SCI includes primary spinal cord injuries and secondary spinal cord injuries. The secondary injury refers to the pathological process or reaction after the primary injury. Although SCI has always been thought to be an incurable injury, the human nerve has the ability to repair itself after an injury. However, the reparability is limited because glial scar formation impedes functional recovery. There is a type of astrocyte that can differentiate into two forms of reactive astrocytes known as ‘A1’ and ‘A2’ astrocytes. A1 astrocytes release cytotoxic chemicals that cause neurons and oligodendrocytes to die and perform a harmful role. A2 astrocytes can produce neurotrophic factors and act as neuroprotectors. This article discusses ways to block A1 astrocytes while stimulating A2 astrocytes to formulate a new treatment for spinal cord injury.
Interleukin-33 (IL-33), IL-36, and IL-38 are members of the IL-1 cytokine family. The expression of each cytokine has been reported to be increased in the inflamed mucosa of patients with inflammatory bowel disease (IBD). IL-33 and IL-36 have been studied for pro- and anti-inflammatory functions, and IL-38 has been characterized as an anti-inflammatory cytokine by antagonizing the IL-36 receptor (IL-36R). IL-33 is a nuclear cytokine constitutively expressed by certain cell types such as epithelial, endothelial, and fibroblast-like cells and released on necrotic cell death. IL-33 mainly induces type 2 immune response through its receptor suppression tumorigenicity 2 (ST2) from Th2 cells and type 2 innate lymphoid cells (ILC2s), but also by stimulating Th1 cells, regulatory T cells, and CD8+ T cells. IL-36 cytokines consist of three agonists: IL-36α, IL-36β, and IL-36γ, and two receptor antagonists: IL-36R antagonist (IL-36Ra) and IL-38. All IL-36 cytokines bind to the IL-36R complex and exert various functions through NF-κB and mitogen-activated protein kinase (MAPK) pathways in inflammatory settings. IL-33 and IL-36 also play a crucial role in intestinal fibrosis characteristic manifestation of CD. In this review, we focused on the current understanding of the pro- and anti-inflammatory roles of IL-33, IL-36, and IL38 in experimental colitis and IBD patients.
Purpose:
Epithelial-mesenchymal transition (EMT) is an important characteristic in the remodeling of chronic rhinosinusitis with nasal polyps (CRSwNP). IL-36γ and fibroblast activation protein (FAP) may exacerbate remodeling in CRS. Here, we aimed to determine whether IL-36γ and FAP expression are associated with EMT and may be a predictor for CRSwNP prognosis.
Methods:
52 non-Eos CRSwNP patients and 12 control patients were obtained and were followed up for more than 1 year after surgery. IL-36γ, FAP and EMT markers expression were evaluated by real-time polymerase chain reaction and western-blot. Masson trichrome staining was adopted to assess tissue fibrotic changes. Furthermore, the soluble form of IL-36γ and FAP in nasal secretions were detect by ELISA.
Results:
While basal expression of E-cadherin decreased, the expression of IL-36γ, vimentin and FAP increased in nasal polyps. In well prognosis patients, the expression of IL-36γ, vimentin and FAP were significantly decreased than in poor prognosis patients, while the protein expression of E-cadherin was increased. The protein expression of IL-36γ was notably increased in recurrent nasal polyps than in preoperation specimens. A positive relationship between IL-36γ and FAP expression, a negative relationship between IL-36γ and E-cad expression was noted. The soluble form of IL-36γ and FAP increased during the development of non-Eos CRSwNP, with the highest level in poor prognosis patients after surgery.
Conclusion:
Non-Eos CRSwNP have partially undergone EMT under baseline conditions. IL-36γ and FAP expression were related with EMT, the soluble form of IL-36γ and FAP in nasal-secretions may predict the prognosis of patients.
Zusammenfassung
Die generalisierte pustulöse Psoriasis (GPP) ist eine seltene, schwere, potenziell lebensbedrohliche, autoinflammatorische, neutrophile Hauterkrankung, die von Fieber und Leukozytose begleitet sein kann. Diese Arbeit beschreibt den aktuellen Wissensstand zur GPP bezüglich Klassifizierung, (Differential‐)Diagnostik und Prävalenz. Wir präsentieren eine Gegenüberstellung der Genetik und Pathoimmunologie der GPP und Psoriasis vulgaris mit den zentralen Mechanismen der Autoimmunologie und Autoinflammation. Die derzeit verfügbaren therapeutischen Optionen, Expertenempfehlungen zur Therapie sowie Daten früher klinischer Studien zur Untersuchung zielgerichteter Therapien werden in dieser Arbeit vorgestellt. Als Ergebnis unserer Diskussionsrunde mit 13 Experten für Psoriasis vulgaris und GPP geben wir einen integrierten Überblick über Indikation und Therapie basierend auf unseren persönlichen Erfahrungen und präsentieren einen Ausblick zu weiteren Forschungsfragen. Dieser Artikel verdeutlicht insbesondere den hohen ungedeckten Bedarf bei der GPP, da es bis heute keine zufriedenstellende Diagnose‐ oder Behandlungsmethode gibt und neue Behandlungsmöglichkeiten für die Betroffenen von großem therapeutischem Nutzen sein werden.
Purpose of review:
Psoriasis vulgaris is the commonest presentation of psoriatic disease, but morphologic variants such as pustular psoriasis (PP) and a closely related disease, pityriasis rubra pilaris (PRP), have been known for a long time, have been associated with rheumatologic manifestations indistinguishable from psoriatic arthritis (PsA) that may go unrecognized, and often represent a therapeutic conundrum. There is recent evidence that underlying genetic and pathogenetic differences may provide the basis for newer therapeutic approaches.
Recent findings:
This narrative review highlights the clinical, genetic and pathogenetic characteristics of PP and PRP, their association with PsA and recent developments in their treatment, especially with biologic agents targeting IL-36 and other cytokines of pathogenic relevance.
Summary:
The clinical manifestations of PP and PRP are less well known to rheumatologists than those of psoriasis, and recent advances in our insight on their pathogenesis may eventually overcome the therapeutic difficulties faced by dermatologists and rheumatologists in the management of these diseases and their rheumatologic manifestations.
Generalized pustular psoriasis (GPP) is a rare, severe, potentially life-threatening, autoinflammatory, neutrophilic skin disease that may be accompanied by fever and leukocytosis. This paper describes the current state of knowledge on GPP in terms of classification, (differential) diagnosis and prevalence. We present a comparison of the genetics and pathoimmunology of GPP and psoriasis vulgaris with the central mechanisms of autoimmunology and autoinflammation. The currently available therapeutic options, expert recommendations for therapy, and data from early clinical trials investigating targeted therapies will be summarized. We present the results of our discussion with 13 experts for psoriasis vulgaris and GPP and give an integrated overview of indication and therapy based on our personal experience and present an outlook on further research questions. Collectively, this article highlights the high unmet need in GPP, as there exists no satisfactory method of diagnosis or treatment to date and new treatment options will be of great therapeutic benefit to those affected.
The interleukin-1 (IL-1) family of cytokines and receptors are implicated in the functioning of innate and adaptive immunity and the genesis of inflammation. They are widely expressed in structural and immune cells with marked expression within barrier mucosal surfaces. In the lung, gut and skin, which are common entry sites for pathogens, they play essential functions in maintaining the functional integrity of the barrier and manage innate and adaptive immunity in response to insult and infections. In tissue sites, the IL-1 cytokines are tightly regulated by mechanisms involving decoy receptors and protease degradation. Dysregulation of these processes are associated with aberrant tissue inflammation leading to a number of inflammatory diseases. This review will address the roles of the different IL-1 cytokines at the lung, gut and skin barrier surfaces at homeostasis, and their roles as inflammatory mediators in diseases such as asthma, chronic obstructive pulmonary disease, inflammatory bowel diseases, atopic dermatitis and psoriasis.
Реакции лекарственной гиперчувствительности создают определенные трудности в клинической практике, связанные с их диагностикой, лечением и профилактикой, а также могут представлять собой угрозу здоровью и жизни пациентов. Острый генерализованный экзантематозный пустулез – это тяжелая, обычно медикаментозная кожная реакция, характеризующаяся острым началом с образованием множества стерильных пустул на эритематозном фоне, лихорадкой и нейтрофилией.
Drug hypersensitivity reactions create certain difficulties in clinical practice related to the diagnosis, treatment and prophylaxis, and may also cause danger to health or life of patients. Acute generalized exanthematous pustulosis represents a severe, usually drug-related skin reaction characterized by acute onset of mainly sterile pustules on an erythematous background, fever and neutrophilia.
Interleukin (IL)-36 is a subfamily, of the IL-1 super-family and includes IL-36α, IL-36β, IL-36γ, IL-38 and IL-36Ra. IL-36 cytokines are involved in the pathology of multiple tissues, including skin, lung, oral cavity, intestine, kidneys and joints. Recent studies suggest that IL-36 signaling regulates autoimmune disease in addition to antibacterial and antiviral responses. Most research has focused on IL-36 in skin diseases such as psoriasis, however, studies on intestinal diseases are also underway. This review outlines what is known about the bioactivity of the IL-36 subfamily and its role in the pathogenesis of intestinal diseases such as inflammatory bowel disease, colorectal cancer, gut dysbacteriosis and infection, and proposes that IL-36 may be a target for novel therapeutic strategies to prevent or treat intestinal diseases.
Objective
The aim of this study was to determine the serum adiponectin and interleukin-36 alpha (IL-36α) levels in polycystic ovary syndrome (PCOS), and their relationship with obesity.
Materials and methods
This observatory study included 80 PCOS patients and 58 controls. The clinical, biochemical, and hormonal parameters, and serum adiponectin and IL-36α levels of the patients were evaluated.
Results
The serum IL-36α levels of the PCOS patients were significantly lower when compared to the control group, despite a similar mean body mass index (BMI) (P = 0.000). The adiponectin levels were significantly lower in the obese PCOS group when compared to the obese control group (P = 0.03). The plasma IL-36α level was positively correlated with adiponectin level, but negatively correlated with the serum LH level (P = 0.000 and P = 0.004, respectively). Using receiver operating characteristic analysis, the cut-off value of IL-36α was calculated as 0.815 for PCOS. In the multiple binary logistic regression analysis, IL-36α (OR [95% CI] 0.432 [0.303, 0.616], P < 0.001) and adiponectin (OR [95% CI] 1.044 [1.005, 1.084], P = 0.028) were determined to be significantly associated with PCOS.
Conclusion
A reduced IL-36α level may play a role in the pathogenesis of ovulatory disfunction and insulin resistance in PCOS patients. Further studies are needed to understand the pathogenic and clinical significance of the IL-36 system in PCOS.
Background: CAR-T cells are chimeric antigen receptor (CAR)-T cells; they are target-specific engineered cells on tumor cells and produce T cell-mediated antitumor responses. CAR-T cell therapy is the “first-line” therapy in immunotherapy for the treatment of highly clonal neoplasms such as lymphoma and leukemia. This adoptive therapy is currently being studied and tested even in the case of solid tumors such as osteosarcoma since, precisely for this type of tumor, the use of immune checkpoint inhibitors remained disappointing. Although CAR-T is a promising therapeutic technique, there are therapeutic limits linked to the persistence of these cells and to the tumor’s immune escape. CAR-T cell engineering techniques are allowed to express interleukin IL-36, and seem to be much more efficient in antitumoral action. IL-36 is involved in the long-term antitumor action, allowing CAR-T cells to be more efficient in their antitumor action due to a “cross-talk” action between the “IL-36/dendritic cells” axis and the adaptive immunity. Methods: This analysis makes the model useful for evaluating cell dynamics in the case of tumor relapses or specific understanding of the action of CAR-T cells in certain types of tumor. The model proposed here seeks to quantify the action and interaction between the three fundamental elements of this antitumor activity induced by this type of adoptive immunotherapy: IL-36, “armored” CAR-T cells (i.e., engineered to produce IL-36) and the tumor cell population, focusing exclusively on the action of this interleukin and on the antitumor consequences of the so modified CAR-T cells. Mathematical model was developed and numerical simulations were carried out during this research. The development of the model with stability analysis by conditions of Routh–Hurwitz shows how IL-36 makes CAR-T cells more efficient and persistent over time and more effective in the antitumoral treatment, making therapy more effective against the “solid tumor”. Findings: Primary malignant bone tumors are quite rare (about 3% of all tumors) and the vast majority consist of osteosarcomas and Ewing’s sarcoma and, approximately, the 20% of patients undergo metastasis situations that is the most likely cause of death. Interpretation: In bone tumor like osteosarcoma, there is a variation of the cellular mechanical characteristics that can influence the efficacy of chemotherapy and increase the metastatic capacity; an approach related to adoptive immunotherapy with CAR-T cells may be a possible solution because this type of therapy is not influenced by the biomechanics of cancer cells which show peculiar characteristics.
Background Behcet’s syndrome (BS) is a systemic vasculitic disorder. This study aimed to investigate the levels of serum IL-36α and IL-36Ra in patients with BS.
Material and Methods A total of 80 subjects (60 BS patients and 20 healthy controls [HC]) were included.
Results The median IL-36α level was 0.11 ng/ml in the BS group and 0.09 ng/ml in the HC group (p=0.058). The mean IL-36Ra level was 13.62 pg/ml in the BS group and 13.26 pg/ml in the HC group (p=0.348). Serum IL-36Ra levels of the active group were significantly higher (p=0.037). Patients with oral ulcers and central nervous system involvement had higher serum IL36Ra levels. In the BS group, a positive correlation was found between serum IL-36Ra and CRP. In a multivariate analysis, the IL-36Ra level (OR=1.067; 95% CI=1.001–1.137; p=0.045) was independently associated with disease activity.
Conclusion According to these findings, it is not clear whether such a slight difference is clinically significant, but they suggest that the IL-36 cytokine family may play a role in the course of the disease.
Background
The IL-36 pathway plays a key role in the pathogenesis of generalized pustular psoriasis (GPP). In a proof-of-concept clinical trial, treatment with spesolimab, an anti-IL-36 receptor antibody, resulted in rapid skin and pustular clearance in patients presenting with GPP flares.
Objective
To compare the molecular profiles of lesional and non-lesional skin from patients with GPP or palmoplantar pustulosis (PPP) with skin from healthy volunteers, and to investigate the molecular changes after spesolimab treatment in the skin and blood of patients with GPP flares.
Methods
Pre- and post-treatment skin and blood samples were collected from patients with GPP who participated in a single-arm, Phase I study (n = 7). Skin biopsies from patients with PPP (n = 8) and healthy volunteers (n = 16) were obtained for comparison at baseline. Biomarkers were assessed by RNA sequencing, histopathology and immunohistochemistry.
Results
In GPP and PPP lesions, 1287 transcripts were commonly up- or downregulated. Selected transcripts from the IL-36 signalling pathway were upregulated in untreated GPP and PPP lesions. In patients with GPP, IL-36 pathway-related signatures, T helper (Th)1/Th17 and innate inflammation signalling, neutrophilic mediators and keratinocyte-driven inflammation pathways, were downregulated by spesolimab as early as Week 1. Spesolimab also decreased related serum biomarkers and cell populations in the skin lesions from patients with GPP, including CD3⁺ T, CD11c⁺, IL-36γ⁺ cells and lipocalin-2-expressing cells.
Conclusion
In patients with GPP, spesolimab showed rapid modulation of commonly dysregulated molecular pathways in GPP and PPP, which may be associated with improved clinical outcomes.
We have previously reported that direct injection of dendritic cells (DC) engineered to express the Type-1 transactivator Tbet (i.e., DC.Tbet) into murine tumors results in antitumor efficacy in association with the development of structures resembling tertiary lymphoid organs (TLO) in the tumor microenvironment (TME). These TLO contained robust infiltrates of B cells, DC, NK cells, and T cells in proximity to PNAd⁺ blood vessels; however, they were considered incomplete, since the recruited B cells failed to organize into classic germinal center-like structures. We now report that antitumor efficacy and TLO-inducing capacity of DC.Tbet-based i.t. therapy is operational in peripheral lymph node-deficient LTA−/− mice, and that it is highly dependent upon a direct Tbet target gene product, IL-36γ/IL-1F9. Intratumoral DC.Tbet fails to provide protection to tumor-bearing IL-36R−/− hosts, or to tumor-bearing wild-type recipient mice co-administered rmIL-1F5/IL-36RN, a natural IL-36R antagonist. Remarkably, the injection of tumors with DC engineered to secrete a bioactive form of mIL-36γ (DC.IL36γ) also initiated therapeutic TLO and slowed tumor progression in vivo. Furthermore, DC.IL36γ cells strongly upregulated their expression of Tbet, suggesting that Tbet and IL-36γ cooperate to reinforce each other's expression in DC, rendering them competent to promote TLO formation in an “immunologically normalized,” therapeutic TME.
Regulatory and effector T helper (Th) cells are abundant at mucosal surfaces, especially in the intestine, where they control the critical balance between tolerance and inflammation. However, the key factors that reciprocally dictate differentiation along these specific lineages remain incompletely understood. Here we report that the interleukin-1 (IL-1) family member IL-36γ signals through IL-36 receptor, myeloid differentiation primary response gene 88, and nuclear factor-κBp50 in CD4⁺ T cells to potently inhibit Foxp3-expressing induced regulatory T cell (Treg) development, while concomitantly promoting the differentiation of Th9 cells via a IL-2-STAT5- (signal transducer and activator of transcription factor 5) and IL-4-STAT6-dependent pathway. Consistent with these findings, mice deficient in IL-36γ were protected from Th cell–driven intestinal inflammation and exhibited increased colonic Treg cells and diminished Th9 cells. Our findings thus reveal a fundamental contribution for the IL-36/IL-36R axis in regulating the Treg–Th9 cell balance with broad implications for Th cell–mediated disorders, such as inflammatory bowel diseases and particularly ulcerative colitis.
Influenza virus causes a respiratory disease in humans that can progress to lung injury with fatal outcome. The interleukin (IL)-36 cytokines are newly described IL-1 family cytokines that promote inflammatory responses via binding to the IL-36 receptor (IL-36R). The mechanism of expression and the role of IL-36 cytokines are poorly understood. Here, we investigated the role of IL-36 cytokines in modulating the innate inflammatory response during influenza virus-induced pneumonia in mice. The intranasal administration of influenza virus upregulated IL-36α mRNA and protein production in the lungs. In vitro, influenza virus-mediated IL-36α but not IL-36γ is induced and secreted from alveolar epithelial cells (AECs) through both a caspase-1 and caspase-3/7 dependent pathway. IL-36α was detected in microparticles shed from AECs and promoted the production of pro-inflammatory cytokines and chemokines in respiratory cells. IL-36R-deficient mice were protected from influenza virus-induced lung injury and mortality. Decreased mortality was associated with significantly reduced early accumulation of neutrophils and monocytes/macrophages, activation of lymphocytes, production of pro-inflammatory cytokines and chemokines, and permeability of the alveolar-epithelial barrier in despite impaired viral clearance. Taken together, these data indicate that IL-36 ligands exacerbate lung injury during influenza virus infection.Mucosal Immunology advance online publication 14 December 2016; doi:10.1038/mi.2016.107.
Geographic tongue (GT) is a benign inflammatory disorder of unknown etiology. Epidemiology and histopathology in previous studies found that generalized pustular psoriasis (GPP) is a factor associated with GT, but the molecular mechanism remains obscure. To investigate the mechanism of GT, with and without GPP, three cohorts were recruited to conduct genotyping of IL36RN, which is the causative gene of GPP. In a family spanning three generations and diagnosed with only GT (“GT alone”), GT was caused by the c.115+6T>C/p.Arg10ArgfsX1 mutation in the IL36RN gene. An autosomal dominant inheritance pattern with incomplete penetrance was observed. In the cohort consisting of sporadic cases of “GT alone” (n = 48), significant associations between GT and three IL36RN variants (c.115+6T>C/p.Arg10ArgfsX1, c.169G>A/p.Val57Ile and c.29G>A/p.Arg10Gln) were shown. In the GPP patient cohort (n = 56) and GPP family member cohort (n = 67), a significant association between the c.115+6T>C mutation and the simultaneous presence of GPP and GT was observed when compared to the presence of GPP without GT (P < 0.05). Biopsies revealed similarities among GT patients with different genotypes (AA, Aa and aa), with the neutrophils prominently infiltrating the epidermis. Western-blot analysis showed that the expression ratio of IL-36Ra/IL-36γ in lesioned tongues with individuals harboring different genotypes (AA, Aa and aa, n = 3, respectively) decreased significantly compared to controls (n = 3). We describe the mechanism of GT for the first time: some cases of GT are caused by IL36RN mutations, while those lacking mutations are associated with an imbalance in expression between IL-36Ra and IL-36γ proteins in tongue tissue.
Electronic supplementary material
The online version of this article (doi:10.1007/s00439-016-1750-y) contains supplementary material, which is available to authorized users.
Allergic asthma is characterized by a strong Th2 response with inflammatory cell recruitment and structural changes in the lung. Papain is a protease allergen disrupting the airway epithelium triggering a rapid inflammation with eosinophilia mediated by innate lymphoid cell activation (ILC2) and leading to a Th2 immune response. In this study, we focused on inflammatory responses to a single exposure to papain and showed that intranasal administration of papain results in the recruitment of inflammatory cells, including neutrophils and eosinophils with a rapid production of IL-1α, IL-1β, and IL-33. The inflammatory response is abrogated in the absence of IL-1R1 and MyD88. To decipher the cell type(s) involved in MyD88 dependent IL-1R1/MyD88 signaling, we used new cell-specific MyD88 deficient mice and found that the deletion of MyD88 signaling in single cell types such as T cells, epithelial cells, CD11c-positive or myeloid cells leads to only a partial inhibition compared to complete absence of MyD88, suggesting that several cell types contribute to the response. Importantly, the inflammatory response is largely ST2 and IL-36R independent. In conclusion, IL-1R1 signaling via MyD88 is critical for the first step of inflammatory response to papain. This article is protected by copyright. All rights reserved
Human and mouse neonates exhibit limited vaccine responses characterized by predominant Th2 and limited Th1 responses. Because IL-36 exerts a synergic adjuvant effect with IL-12, enhancing Th1 polarization in adult (AD) mice, we administered IL-36β to neonatal (1-wk old) and AD control mice at the time of immunization with tetanus toxoid adsorbed to aluminum hydroxide (TT/Alum). Unexpectedly, the combination of IL-36β with TT/Alum, which was well tolerated in AD mice, proved toxic and even lethal in neonates. This neonatal toxicity was associated with high Il36r mRNA expression in neonatal liver, resulting in increased cytokine production. Liver Il36r mRNA expression decreased with the termination of fetal liver hematopoiesis, and this decrease correlated with a complete protection from TT/Alum/IL-36β-induced mortality. The combination of IL-36β and TT/Alum induced the rapid production of TNF-α and IFN-γ by liver myeloid and lymphoid cells, respectively. These responses were less marked when IL-36β was used alone, with no adverse effect. The toxicity of IL-36β + TT/Alum was abrogated by the administration of a neutralizing anti-TNF-α Ab, confirming causality. In conclusion, liver myeloid cells in neonatal mice are an important source of proinflammatory cytokines that may lead to TNF-α-mediated toxicity and even lethality.
Prominent skin involvement is a defining characteristic of autoinflammatory disorders (AID) caused by abnormal IL-1 signalling. However, the pathways and cell types that drive cutaneous AID features remain poorly understood. We sought to address this issue by investigating the pathogenesis of pustular psoriasis, a model of AID with predominant cutaneous manifestations. We specifically characterised the impact of mutations affecting AP1S3, a disease gene previously identified by our group and validated here in a newly ascertained patient resource. We first demonstrated that AP1S3 expression is distinctively elevated in keratinocytes. Since AP1S3 encodes a protein implicated in autophagosome formation, we next investigated the effects of gene silencing on this pathway. We found that AP1S3 knockout disrupts keratinocyte autophagy, causing abnormal accumulation of p62, an adaptor protein mediating NF-κB activation. We demonstrated that as a consequence, AP1S3 deficient cells up-regulate IL-1 signalling and over-express IL-36α, a cytokine that is emerging as an important mediator of skin inflammation. These abnormal immune profiles were recapitulated by pharmacological inhibition of autophagy and verified in patient keratinocytes, where they were reversed by IL-36 blockade. These findings demonstrate that keratinocytes play a key role in skin autoinflammation and identify autophagy modulation of IL-36 signalling as a therapeutic target.
Signal transduction by the IL-36 receptor (IL-36R) is linked to several human diseases. However, the structure and function
of the IL-36R is not well understood. A molecular model of the IL-36R complex was generated and a cell-based reporter assay
was established to assess the signal transduction of recombinant subunits of the IL-36R. Mutational analyses and functional
assays have identified residues of the receptor subunit IL-1Rrp2 needed for cytokine recognition, stable protein expression,
disulfide bond formation and glycosylation that are critical for signal transduction. We also observed that, in the absence
of cytokine, the ectodomain (ECD) of IL-1Rrp2 could interact with itself. In the presence of IL-36 cytokine, the IL-1Rrp2
ECD increased the interaction with the co-receptor IL-1RAcP. Finally, we found that single nucleotide polymorphism A471T in
the Toll-interleukin 1 receptor domain (TIR) of the IL-1Rrp2 that is present in ~2% of the human population, down-regulated
IL-36R signaling by a decrease of interaction with IL-1RAcP.
The interleukin-36 receptor antagonist (IL-36Ra) which regulates IL-36α, -β and -γ is linked to psoriatic inflammation, especially loss-of-function mutations in pustular psoriasis subtypes. As observed with other IL-1 superfamily proteins, the IL-36 members require N-terminal cleavage for full biological activity but the mechanisms of IL-36Ra activation remain poorly defined. Using different blood leukocyte and skin resident cell preparations, and recombinant proteins, we have identified that neutrophil elastase, but not other neutrophil derived proteases, cleaves IL-36Ra into its highly active antagonistic form. The activity of this processed form of IL-36Ra was confirmed in human primary dermal fibroblasts and keratinocytes and in skin equivalents. A significant dose dependent reduction of IL-36 γ induced IL-8 and chemokine ligand 20 (CCL20) levels were detected following addition of the cleaved IL-36Ra compared to full length IL-36Ra. By activating IL-36Ra, the neutrophil derived protease can inhibit IL-36 induced chemokine production, including IL-8 and CCL20, and reduce further inflammatory cell infiltration. These findings strongly indicate neutrophil elastase to be a key enzyme in the biological function of IL-36Ra and that neutrophils can play a regulatory role in psoriatic inflammation with regard to balancing the pro-inflammatory activity of IL-36.
A role for the IL-36 family of cytokines has been identified in the pathogenesis of psoriasis. Although significant mechanistic overlap can exist between psoriasis and inflammatory bowel disease (IBD), to date there have been no reports investigating the IL-36 family in gastrointestinal inflammation. Here we demonstrate that expression levels of IL-36α are specifically elevated in the colonic mucosa of ulcerative colitis patients. This elevated expression is mirrored in the inflamed colonic mucosa of mice, wherein IL-36 receptor deficiency confirmed this pathway as a mediator of mucosal inflammation. Il36r-/- mice exhibited reduced disease severity in an acute DSS-induced model of colitis in association with decreased innate inflammatory cell infiltration to the colon lamina propria. Consistent with these data, infection with the enteropathogenic bacteria Citrobacter rodentium, resulted in reduced innate inflammatory cell recruitment and increased bacterial colonization in the colons of il36r-/- mice. Il36r-/- mice also exhibited altered T helper cell responses in this model, with enhanced Th17 and reduced Th1 responses, demonstrating that IL-36R signaling also regulates intestinal mucosal T-cell responses. These data identify a novel role for IL-36 signaling in colonic inflammation and indicate that the IL-36R pathway may represent a novel target for therapeutic intervention in IBD.Mucosal Immunology advance online publication, 27 January 2016; doi:10.1038/mi.2015.134.
Recent evidence has strongly implicated the IL-1 family cytokines IL-36α, IL-36β, and IL-36γ as key initiators of skin inflammation. Similar to the other members of the IL-1 family, IL-36 cytokines are expressed as inactive precursors and require proteolytic processing for activation; however, the responsible proteases are unknown. Here, we show that IL-36α, IL-36β, and IL-36γ are activated differentially by the neutrophil granule-derived proteases cathepsin G, elastase, and proteinase-3, increasing their biological activity ∼500-fold. Active IL-36 promoted a strong pro-inflammatory signature in primary keratinocytes and was sufficient to perturb skin differentiation in a reconstituted 3D human skin model, producing features resembling psoriasis. Furthermore, skin eluates from psoriasis patients displayed significantly elevated cathepsin G-like activity that was sufficient to activate IL-36β. These data identify neutrophil granule proteases as potent IL-36-activating enzymes, adding to our understanding of how neutrophils escalate inflammatory reactions. Inhibition of neutrophil-derived proteases may therefore have therapeutic benefits in psoriasis.
IL-36α, IL-36β and IL-36γ are highly expressed in skin and are involved in the pathogenesis of psoriasis, while the antagonist IL-36Ra or IL-38, another potential IL-36 inhibitor, limit uncontrolled inflammation. The expression and role of IL-36 cytokines in rheumatoid arthritis (RA) and Crohn's disease (CD) is currently debated. Here, we observed that during imiquimod-induced mouse skin inflammation and in human psoriasis, expression of IL-36α, γ and IL-36Ra, but not IL-36β and IL-38 mRNA, was induced and correlated with IL-1β and Th17 cytokines (IL-17A, IL-22, IL-23, CCL20). In mice with collagen-induced arthritis and in the synovium of patients with RA, IL-36α, β, γ, IL-36Ra and IL-38 were all elevated and correlated with IL-1β, CCL3, CCL4 and MCSF, but not with Th17 cytokines. In the colon of mice with dextran sulfate sodium-induced colitis and in patients with CD, only IL-36α, γ and IL-38 were induced at relatively low levels and correlated with IL-1β and IL-17A. We suggest that only a minor subgroup of patients with RA (17-29%) or CD (25%) had an elevated IL-36 agonists/antagonists ratio, versus 93% of patients with psoriasis. By immunohistochemistry, IL-36 cytokines were produced by various cell types in skin, synovium and colonic mucosa such as keratinocytes, CD68(+) macrophages, dendritic/Langerhans cells, and CD79α(+) plasma cells. In primary cultures of monocytes or inflammatory macrophages (M1), IL-36β and IL-36Ra were constitutively produced, but IL-36α, γ and IL-38 were produced after lipopolysaccharide stimulation. These distinct expression profiles may help to explain why only subgroups of RA and CD patients have a potentially elevated IL-36 agonists/antagonists ratio. This article is protected by copyright. All rights reserved.
IL-1 family members are central mediators of host defense. In this article, we show that the novel IL-1 family member IL-36γ was expressed during experimental colitis and human inflammatory bowel disease. Germ-free mice failed to induce IL-36γ in response to dextran sodium sulfate (DSS)-induced damage, suggesting that gut microbiota are involved in its induction. Surprisingly, IL-36R-deficient (Il1rl2(-/-)) mice exhibited defective recovery following DSS-induced damage and impaired closure of colonic mucosal biopsy wounds, which coincided with impaired neutrophil accumulation in the wound bed. Failure of Il1rl2(-/-) mice to recover from DSS-induced damage was associated with a profound reduction in IL-22 expression, particularly by colonic neutrophils. Defective recovery of Il1rl2(-/-) mice could be rescued by an aryl hydrocarbon receptor agonist, which was sufficient to restore IL-22 expression and promote full recovery from DSS-induced damage. These findings implicate the IL-36/IL-36R axis in the resolution of intestinal mucosal wounds.
Background:
Interleukin (IL)-36 cytokines are recently reported member of the IL-1 cytokine family. However, there is little information regarding the association between IL-36 cytokines and gut inflammation. In the present study, we investigated the biological activity of IL-36α and IL-36γ using human colonic subepithelial myofibroblasts (SEMFs).
Methods:
The mRNA expression and the protein expression of target molecules in SEMFs were evaluated using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The intracellular signaling of IL-36 cytokines was analyzed using Western blot analysis and small interfering RNAs (siRNAs) specific for MyD88 adaptor proteins (MyD88 and IRAK1) and NF-κB p65.
Results:
IL-36α and IL-36γ significantly enhanced the secretion of IL-6 and CXC chemokines (CXCL1, CXCL2, and CXCL8) by SEMFs. The combination of IL-36α/γ and IL-17A or of IL-36α/γ and tumor necrosis factor-α showed a synergistic effect on the induction of IL-6 and CXC chemokines. The mRNA expression of proinflammatory mediators induced by IL-36α and/or IL-36γ was significantly suppressed by transfection of siRNA for MyD88 or IRAK1. Both inhibitors of mitogen activated protein kinases and siRNAs specific for NF-κBp65 significantly reduced the expression of IL-6 and CXC chemokines induced by IL-36α and/or IL-36γ.
Conclusion:
These results suggest that IL-36α and IL-36γ contribute to gut inflammation through the induction of proinflammatory mediators.
Background:
Experimental autoimmune encephalomyelitis (EAE) is a model of inflammatory demyelinating diseases mediated by different types of leukocytes. How these cells communicate with each other to orchestrate autoimmune attacks is not fully understood, especially in the case of neutrophils, whose importance in EAE is newly established. The present study aimed to determine the expression pattern and role of different components of the IL-36 signaling pathway (IL-36α, IL-36β, IL-36γ, IL-36R) in EAE.
Methods:
EAE was induced by either active immunization with myelin peptide, passive transfer of myelin-reactive T cells or injection of pertussis toxin to transgenic 2D2 mice. The molecules of interest were analyzed using a combination of techniques, including quantitative real-time PCR (qRT-PCR), flow cytometry, Western blotting, in situ hybridization, and immunohistochemistry. Microglial cultures were treated with recombinant IL-36γ and analyzed using DNA microarrays. Different mouse strains were subjected to clinical evaluation and flow cytometric analysis in order to compare their susceptibility to EAE.
Results:
Our observations indicate that both IL-36γ and IL-36R are strongly upregulated in nervous and hematopoietic tissues in different forms of EAE. IL-36γ is specifically expressed by neutrophils, while IL-36R is expressed by different immune cells, including microglia and other myeloid cells. In culture, microglia respond to recombinant IL-36γ by expressing molecules involved in neutrophil recruitment, such as Csf3, IL-1β, and Cxcl2. However, mice deficient in either IL-36γ or IL-36R develop similar clinical and histopathological signs of EAE compared to wild-type controls.
Conclusion:
This study identifies IL-36γ as a neutrophil-related cytokine that can potentially activate microglia, but that is only correlative and not contributory in EAE.
IL-36 cytokines are members of the IL-1 family of cytokines that stimulate dendritic cells and T cells leading to enhanced T helper 1 responses in vitro and in vivo; however, their role in host defense has not been fully addressed thus far. The objective of this study was to examine the role of IL-36R signaling in the control of mycobacterial infection, using models of systemic attenuated M. bovis BCG infection and virulent aerogenic M. tuberculosis infection. IL-36γ expression was increased in the lung of M. bovis BCG infected mice. However, IL-36R deficient mice infected with M. bovis BCG showed similar survival and control of the infection as compared to wild-type mice, although their lung pathology and CXCL1 response were transiently different. While highly susceptible TNF-α deficient mice succumbed with overwhelming M. tuberculosis infection, and IL-1RI deficient mice showed intermediate susceptibility, IL-36R-deficient mice controlled the infection, with bacterial burden, lung inflammation and pathology, similar to wild-type controls. Therefore, IL-36R signaling has only limited influence in the control of mycobacterial infection.
The pathogenesis of many autoimmune diseases initially based on a redundant or prolonged activation of the innate immune system. It was suggested that an excessive activation of the innate immunity is often the result of a chronic inflammatory process in the organism. This inflammation can be induced by exogenous and endogenous alarm factor, or alarmins. We believe that the recently discovered neutrophil extracellular traps, or NETs, completely meet the criteria of alarmins. This review summarizes current knowledge concerning the general characteristics of NETs, their antimicrobial properties, and their role in the development of chronic inflammatory processes that underlie the pathogenesis of psoriasis and atherosclerosis. Studies on the NETosis can provide the foundation for developing new diagnostic methods and effective treatment of chronic inflammatory and autoimmune diseases.
Copyright © 2015 Elsevier B.V. All rights reserved.
Introduction
Interleukin (IL)-36α is a newly described member of the IL-1 cytokine family with a known inflammatory and pathogenic function in psoriasis. Recently, we could demonstrate that the receptor (IL-36R), its ligand IL-36α and its antagonist IL-36Ra are expressed in synovial tissue of arthritis patients. Furthermore, IL-36α induces MAP-kinase and NFκB signaling in human synovial fibroblasts with subsequent expression and secretion of pro-inflammatory cytokines.
Methods
To understand the pathomechanism of IL-36 dependent inflammation, we investigated the biological impact of IL-36α signaling in the hTNFtg mouse. Also the impact on osteoclastogenesis by IL-36α was tested in murine and human osteoclast assays.
Results
Diseased mice showed an increased expression of IL-36R and IL-36α in inflamed knee joints compared to wildtype controls. However, preventively treating mice with an IL-36R blocking antibody led to no changes in clinical onset and pattern of disease. Furthermore, blockade of IL-36 signaling did not change histological signs of TNF-induced arthritis. Additionally, no alteration on bone homeostasis was observed in ex vivo murine and human osteoclast differentiation assays.
Conclusion
Thus we conclude that IL-36α does not affect the development of inflammatory arthritis.
The IL-1 family consists of 11 cytokines that control a complex network of proinflammatory signals critical for regulating immune responses to infections. They also play a central role in numerous chronic inflammatory disorders. Accordingly, inhibiting the activities of these cytokines is an important therapeutic strategy for treating autoimmune diseases and lymphomas. Agonist cytokines in the IL-1 family activate signaling by binding their cognate receptor and then recruiting a receptor accessory protein. Conversely, antagonist cytokines bind their cognate receptor but prohibit recruitment of receptor accessory protein, which precludes functional signaling complexes. The IL-36 subfamily of cytokines is the most diverse, including three agonists and at least one antagonist, and is the least well-characterized group within this family. Signaling through the IL-36 receptor directly stimulates dendritic cells and primes naive CD4 T cells for Th1 responses. Appropriately balanced IL-36 signaling is a critical determinant of skin and lung health. IL-36 signaling has been presumed to function analogously to IL-1 signaling. In this study, we have defined molecular determinants of agonist and antagonist signaling through the IL-36 receptor. We present the crystal structure of IL-36γ, which, to our knowledge, is the first reported structure of an IL-36 agonist. Using this structure as a guide, we designed a comprehensive series of IL-36 agonist/antagonist chimeric proteins for which we measured binding to the IL-36 receptor/IL-1 receptor accessory protein complex and functional activation and inhibition of signaling. Our data reveal how the fine specificity of IL-36 signaling is distinct from that of IL-1.
Previous attempts to gain insight into the pathogenesis of psoriasis and eczema by comparing their molecular signatures were hampered by the high interindividual variability of those complex diseases. In patients affected by both psoriasis and nonatopic or atopic eczema simultaneously (n = 24), an intraindividual comparison of the molecular signatures of psoriasis and eczema identified genes and signaling pathways regulated in common and exclusive for each disease across all patients. Psoriasis-specific genes were important regulators of glucose and lipid metabolism, epidermal differentiation, as well as immune mediators of T helper 17 (TH17) responses, interleukin-10 (IL-10) family cytokines, and IL-36. Genes in eczema related to epidermal barrier, reduced innate immunity, increased IL-6, and a TH2 signature. Within eczema subtypes, a mutually exclusive regulation of epidermal differentiation genes was observed. Furthermore, only contact eczema was driven by inflammasome activation, apoptosis, and cellular adhesion. On the basis of this comprehensive picture of the pathogenesis of psoriasis and eczema, a disease classifier consisting of NOS2 and CCL27 was created. In an independent cohort of eczema (n = 28) and psoriasis patients (n = 25), respectively, this classifier diagnosed all patients correctly and also identified initially misdiagnosed or clinically undifferentiated patients.
The IL-1 family members IL-36α (IL-1F6), IL-36β (IL-1F8), and IL-36γ (IL-1F9) and the receptor antagonist IL-36Ra (IL-1F5) constitute a novel signaling system that is poorly understood. We now show that these cytokines have profound effects on the skin immune system. Treatment of human keratinocytes with IL-36 cytokines significantly increased the expression of CXCL1, CXCL8, CCL3, CCL5, and CCL20, potent chemotactic agents for activated leukocytes, and IL-36α injected intradermally resulted in chemokine expression, leukocyte infiltration, and acanthosis of mouse skin. Blood monocytes, myeloid dendritic cells (mDC), and monocyte-derived DC (MO-DC) expressed IL-36R and responded to IL-36. In contrast, no direct effects of IL-36 on resting or activated human CD4(+) or CD8(+) T cells, or blood neutrophils, could be demonstrated. Monocytes expressed IL-1A, IL-1B, and IL-6 mRNA and IL-1β and IL-6 protein, and mDC upregulated surface expression of CD83, CD86, and HLA-DR and secretion of IL-1β and IL-6 after treatment with IL-36. Furthermore, IL-36α-treated MO-DC enhanced allogeneic CD4(+) T cell proliferation, demonstrating that IL-36 can stimulate the maturation and function of DC and drive T cell proliferation. These data indicate that IL-36 cytokines actively propagate skin inflammation via the activation of keratinocytes, APC, and, indirectly, T cells.
Preoperative or perioperative ischemic injury of allografts predisposes to graft arteriosclerosis, the major cause of late graft failure. We hypothesize that injured tissues release mediators that increase the production of pathogenic cytokines by alloreactive T cells. We find that freeze-thaw lysates of human endothelial cells (EC) increase both IFN-γ and IL-17 production by human CD4⁺ T cells activated by HLA-DR⁺ allogeneic EC. Immunoadsorption of high-mobility group box 1 protein (HMGB1) reduces this activity in the lysates by about one-third, and recombinant HMGB1 increases T cell cytokine production. HMGB1 acts by inducing IL-1β secretion from contaminating monocytes via TLR4 and CD14. Upon removal of contaminating monocytes, the remaining stimulatory activity of EC lysates is largely attributable to IL-1α. Recombinant IL-1 directly augments IFN-γ and IL-17 production by activated memory CD4⁺ T cells, which express IL-1R1. Furthermore, IL-1 increases the frequency of alloreactive memory CD4⁺ T cells that produce IL-17, but not those that produce IFN-γ, in secondary cultures. Our results suggest that IL-1, released by injured EC or by HMGB1-stimulated monocytes, is a key link between injury and enhanced alloimmunity, offering a new therapeutic target for preventing late graft failure.
Generalized pustular psoriasis (GPP) is a rare inflammatory skin disease that can be life-threatening. Recently, it has been reported that familial GPP (FGPP) is caused by homozygous or compound heterozygous mutations of IL36RN. However, the majority of GPP cases are sporadic and it is controversial whether IL36RN mutations are a causative/predisposing factor for sporadic GPP. We searched for IL36RN mutations in two groups of GPP patients in the Japanese population in this study: GPP without psoriasis vulgaris (PV), and GPP with PV. Eleven cases of GPP without PV (GPP alone) and 20 cases of GPP accompanied by PV (GPP with PV) were analyzed. Surprisingly, 9 out of 11 cases of GPP alone had homozygous or compound heterozygous mutations in IL36RN. In contrast, only 2 of 20 cases of GPP with PV had compound heterozygous mutations in IL36RN. The 2 cases of GPP with PV who had compound heterozygous mutations in IL36RN are siblings, and both cases had PV-susceptible HLA-A*0206. We determined that GPP alone is a distinct subtype of GPP and is etiologically distinguished from GPP with PV, and that the majority of GPP alone is caused by deficiency of the interleukin 36 receptor antagonist (DITRA) due to IL36RN mutations.Journal of Investigative Dermatology accepted article preview online, 22 May 2013; doi:10.1038/jid.2013.230.
Introduction
Interleukin (IL)-36 refers to three related IL-1 family cytokines, IL-36α, IL-36β, and IL-36γ, that bind to the IL-36 receptor (IL-36R). IL-36 exerts proinflammatory effects in skin and lung and stimulates T cell responses. In the present study, we examined the expression and function of IL-36R and its ligands in experimental arthritis.
Methods
Collagen-induced arthritis (CIA), antigen-induced arthritis (AIA), and K/BxN serum transfer-induced arthritis were induced according to standard protocols. Messenger RNA levels for IL-36R and its ligands in the joints of mice with CIA were determined by RT-qPCR. Mice with CIA were injected with a blocking monoclonal anti-IL-36R, a blocking anti-IL-1RI, or their isotype-matched control antibodies at the time of arthritis onset. Anti-IL-36R or control antibodies were also injected at the time of AIA induction. Finally, IL-36R-deficient mice were examined in AIA and serum transfer-induced arthritis. The development and severity of arthritis were assessed by clinical and histological scoring.
Results
IL-36R, IL-36Ra and IL-36γ mRNA were detected in the joints of mice with CIA, but their levels did not correlate with arthritis severity. As opposed to anti-IL-1RI antibody treatment, the injection of an anti-IL-36R antibody was devoid of effect on the development and severity of CIA. The severity of joint inflammation and structural damage in AIA was also unaltered by anti-IL-36R antibody treatment. Finally, the severity of AIA and K/BxN serum transfer-induced arthritis was similar in IL-36R-deficient and wild-type mice.
Conclusions
The development and severity of experimental arthritis are independent of IL-36R signaling.
By concerted action in dendritic (DC) and T cells, T-box expressed in T cells (T-bet, Tbx21) is pivotal for initiation and perpetuation of Th1 immunity. Identification of novel T-bet regulated genes is crucial for further understanding the biology of this transcription factor. By combining siRNA technology with genome-wide mRNA expression analysis, we sought to identify new T-bet regulated genes in pre-dendritic KG1 cells activated by IL-18. One gene robustly dependent on T-bet was IL36γ, a recently described novel IL-1 family member. Promoter analysis revealed a T-bet binding site that, along with a κB site, enables efficient IL-36γ induction. Using knockout animals, IL-36γ reliance on T-bet was extended to murine DC. IL-36γ expression by human myeloid cells was confirmed using monocyte-derived DC and M1 macrophages. The latter model was employed to substantiate dependency of IL-36γ on endogenous T-bet in human primary cells. Ectopic expression of T-bet likewise mediated IL-36γ production in HaCaT keratinocytes which otherwise lack this transcription factor. Additional experiments furthermore revealed that mature IL-36γ has the capability to establish an inflammatory gene expression profile in human primary keratinocytes which displays enhanced mRNA levels for TNFα, CCL20, S100A7, inducible iNOS, and IL-36γ itself. Data presented herein shed further light on involvement of T-bet in innate immunity and suggest that IL-36γ, besides IFNγ, may contribute to functions of this transcription factor in immunopathology.
Psoriasis is a chronic inflammatory disorder of the skin affecting approximately 2% of the world's population. Accumulating evidence has revealed that the IL-23/IL-17/IL-22 pathway is key for development of skin immunopathology. However, the role of keratinocytes and their crosstalk with immune cells at the onset of disease remains poorly understood. Here, we show that IL-36R-deficient (Il36r-/-) mice were protected from imiquimod-induced expansion of dermal IL-17-producing γδ T cells and psoriasiform dermatitis. Furthermore, IL-36R antagonist-deficient (Il36rn-/-) mice showed exacerbated pathology. TLR7 ligation on DCs induced IL-36-mediated crosstalk with keratinocytes and dermal mesenchymal cells that was crucial for control of the pathological IL-23/IL-17/IL-22 axis and disease development. Notably, mice lacking IL-23, IL-17, or IL-22 were less well protected from disease compared with Il36r-/- mice, indicating an additional distinct activity of IL-36 beyond induction of the pathological IL-23 axis. Moreover, while the absence of IL-1R1 prevented neutrophil infiltration, it did not protect from acanthosis and hyperkeratosis, demonstrating that neutrophils are dispensable for disease manifestation. These results highlight a central and unique IL-1-independent role for IL-36 in control of the IL-23/IL-17/IL-22 pathway and development of psoriasiform dermatitis.
Interleukin (IL-) 36 cytokines (previously designated as novel IL-1 family member cytokines; IL-1F5- IL-1F10) constitute a novel cluster of cytokines structurally and functionally similar to members of the IL-1 cytokine cluster. The effects of IL-36 cytokines in inflammatory lung disorders remains poorly understood. The current study sought to investigate the effects of IL-36α (IL-1F6) and test the hypothesis that IL-36α acts as a pro-inflammatory cytokine in the lung in vivo. Intratracheal instillation of recombinant mouse IL-36α induced neutrophil influx in the lungs of wild-type C57BL/6 mice and IL-1αβ(-/-) mice in vivo. IL-36α induced neutrophil influx was also associated with increased mRNA expression of neutrophil-specific chemokines CXCL1 and CXCL2 in the lungs of C57BL/6 and IL-1αβ(-/-) mice in vivo. In addition, intratracheal instillation of IL-36α enhanced mRNA expression of its receptor IL-36R in the lungs of C57BL/6 as well as IL-1αβ(-/-) mice in vivo. Furthermore, in vitro incubation of CD11c(+) cells with IL-36α resulted in the generation of neutrophil-specific chemokines CXCL1, CXCL2 as well as TNFα. IL-36α increased the expression of the co-stimulatory molecule CD40 and enhanced the ability of CD11c(+) cells to induce CD4(+) T cell proliferation in vitro. Furthermore, stimulation with IL-36α activated NF-κB in a mouse macrophage cell line. These results demonstrate that IL-36α acts as a pro-inflammatory cytokine in the lung without the contribution of IL-1α and IL-1β. The current study describes the pro-inflammatory effects of IL-36α in the lung, demonstrates the functional redundancy of IL-36α with other agonist cytokines in the IL-1 and IL-36 cytokine cluster, and suggests that therapeutic targeting of IL-36 cytokines could be beneficial in inflammatory lung diseases.
Significance
IL-36γ is a potent cytokine that drives and orchestrates inflammation. It is strongly expressed at barrier tissues such as the skin and thus is particularly relevant to inflammatory diseases that affect these tissues, including psoriasis. IL-36γ is expressed as an inactive precursor that requires precise N-terminal truncation for activation. In these investigations, we demonstrate that cathepsin S is the major IL-36γ–activating protease expressed by barrier tissues. Moreover, we show that both cathepsin S and IL-36γ are strongly up-regulated in psoriatic inflammation. These findings are important as they both identify the mechanism of IL-36γ activation and highlight that this mechanism may play a central role in the development of psoriatic inflammation.
IL-36 cytokines are proinflammatory and have an important role in innate and adaptive immunity, but the role of IL-36 signaling in renal tubulointerstitial lesions (TILs), a major prognostic feature of renal inflammation and fibrosis, remains undetermined. In this study, increased IL-36α expression detected in renal biopsy specimens and urine samples from patients with renal TILs correlated with renal function impairment. We confirmed the increased expression of IL-36α in the renal tubular epithelial cells of a mouse model of unilateral ureteral obstruction (UUO) and related cell models using mechanically induced pressure, oxidative stress, or high mobility group box 1. In contrast, the kidneys of IL-36 receptor (IL-36R) knockout mice exhibit attenuated TILs after UUO. Compared with UUO-treated wild-type mice, UUO-treated IL-36 knockout mice exhibited markedly reduced NLRP3 inflammasome activation and macrophage/T cell infiltration in the kidney and T cell activation in the renal draining lymph nodes. In vitro, recombinant IL-36α facilitated NLRP3 inflammasome activation in renal tubular epithelial cells, macrophages, and dendritic cells and enhanced dendritic cell-induced T cell proliferation and Th17 differentiation. Furthermore, deficiency of IL-23, which was diminished in IL-36R knockout UUO mice, also reduced renal TIL formation in UUO mice. In wild-type mice, administration of an IL-36R antagonist after UUO reproduced the results obtained in UUO-treated IL-36R knockout mice. We propose that IL-36 signaling contributes to the pathogenesis of renal TILs through the activation of the NLRP3 inflammasome and IL-23/IL-17 axis.
Objectives:
Interleukin 36 (IL-36) is a recently described proinflammatory cytokine, characterized by the induction of inflammatory mediators. In the present study, we investigated the biological activity and the signal transduction of IL-36α in human pancreatic myofibroblasts.
Methods:
The mRNA and protein expression of inflammatory mediators was evaluated using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The expression of IL-36α and its receptor in the pancreatic tissue was evaluated using immunohistochemical technique. Intracellular signaling pathways were evaluated using immunoblotting and specific small interference RNA-transfected cells.
Results:
Interleukin 36α and its receptor complex IL-36R/IL-1RAcP were detected in fibrotic tissue of chronic pancreatitis. Interleukin 36α dose- and time-dependently induced the mRNA expression and protein secretion of CXCL1, CXCL8, MMP-1, and MMP-3 from human pancreatic myofibroblasts. Interleukin 36α assembled MyD88 adaptor proteins (MyD88, TRAF6, IRAK1, and TAK1) into a complex. Furthermore, IL-36α induced the phosphorylation of mitogen-activated protein kinases and the activation of nuclear factor κB and activator protein 1. Mitogen-activated protein kinase inhibitors and small interference RNAs specific for nuclear factor κB and activator protein 1 significantly suppressed the protein secretion of inflammatory mediators induced by IL-36α stimulation.
Conclusions:
It was suggested that IL-36α plays an important role in the pathophysiology of inflammation and fibrosis in the pancreas via an autocrine function.
Interleukin (IL)-36 cytokines belong to the IL-1 family and include three agonists, IL-36 α, β and γ and one inhibitor, IL-36 receptor antagonist (IL-36Ra). IL-36 and IL-1 (α and β) activate similar intracellular pathways via their related heterodimeric receptors, IL-36R/IL-1RAcP and IL-1R1/IL-1RAcP, respectively. However, excessive IL-36 versus IL-1 signaling induces different phenotypes in humans, which may be related to differential expression of their respective receptors.
We examined the expression of IL-36R, IL-1R1 and IL-1RAcP mRNA in human peripheral blood, tonsil and skin immune cells by RT-qPCR. Monocyte-derived dendritic cells (MDDC), M0, M1 or M2-polarized macrophages, primary keratinocytes, dermal macrophages and Langerhans cells (LC) were stimulated with IL-1β or IL-36β. Cytokine production was assessed by RT-qPCR and immunoassays.
The highest levels of IL-36R mRNA were found in skin-derived keratinocytes, LC, dermal macrophages and dermal CD1a⁺ DC. In the blood and in tonsils, IL-36R mRNA was predominantly found in myeloid cells. By contrast, IL-1R1 mRNA was detected in almost all cell types with higher levels in tonsil and skin compared to peripheral blood immune cells. IL-36β was as potent as IL-1β in stimulating M2 macrophages, keratinocytes and LC, less potent than IL-1β in stimulating M0 macrophages and MDDC, and exerted no effects in M1 and dermal macrophages. Levels of IL-1Ra diminished the ability of M2 macrophages to respond to IL-1.
Taken together, these data are consistent with the association of excessive IL-36 signaling with an inflammatory skin phenotype and identify human LC and M2 macrophages as new IL-36 target cells.
Homozygous or compound heterozygous IL36RN gene mutations underlie the pathogenesis of psoriasis-related pustular eruptions including generalized pustular psoriasis (GPP), palmoplantar pustular psoriasis (PPP), acrodermatitis continua of Hallopeau (ACH), and acute generalized exanthematous pustular eruption (AGEP). We identified two unreported IL36RN homozygous mutations (c.41C>A/p.Ser14X and c.420_426del/p.Gly141MetfsX29) in familial GPP cases. We analyzed the impact of a spectrum of IL36RN mutations on IL-36Ra protein by using site-directed mutagenesis and expression in HEK293T cells. This enabled us to differentiate null mutations with complete absence of IL-36Ra (the 2 previously unreported mutants, c.80T>C/p.Leu27Pro, c.28C>T/p.Arg10X, c.280G>T/p.Glu94X, c.368C>G/p.Thr123Arg, c.368C>T/p.Thr123Met, and c.227C>T/p.Pro76Leu) from mutations with decreased (c.95A>G/p.His32Arg, c.142C>T/p.Arg48Trp, c.308C>T/p.Ser113Leu) or unchanged (c.304C>T/p.Arg102Trp and c.104A>G/p.Lys35Arg) protein expression. Functional assays measuring the impact of mutations on the capacity to repress IL-36-dependent activation of the NFκB pathway revealed complete functional impairment for null mutants, whereas partial or no impairment was observed for other mutations considered as hypomorphic. Finally, null mutants were associated with severe clinical phenotypes (GPP, AGEP), while hypomorphic ones were identified in both localized (PPP, ACH) and generalized variants.
Interleukin-36 is a family of novel interleukin-1-like proinflammatory cytokines that are highly expressed in epithelial tissues and several myeloid-derived cell types. Like those of classic interleukin-1 cytokines, the secretion mechanisms of interleukin-36 are not well understood. Interleukin-36γ secretion in dermal epithelial cells requires adenosine 5'-triphosphate, which suggests a nonclassical mechanism of secretion. In this study, murine pulmonary macrophages and human alveolar macrophages were treated with recombinant pathogen-associated molecular patterns (intact bacteria: Klebsiella pneumoniae or Streptococcus pneumoniae). Cell lysates were analyzed for messenger ribonucleic acid by quantitative real-time polymerase chain reaction, and conditioned medium was analyzed for interleukin-36γ by enzyme-linked immunosorbent assay, with or without sonication. In addition, conditioned medium was ultracentrifuged at 25,000 g and 100,000 g, to isolate microparticles and exosomes, respectively, and interleukin-36γ protein was assessed in each fraction by Western blot analysis. Interleukin-36γ mRNA was induced in both murine and human lung macrophages by a variety of pathogen-associated molecular patterns, as well as heat-killed and live Klebsiella pneumoniae and Streptococcus pneumoniae, and induction occurred in a myeloid differentiation response gene 88-dependent manner. Secretion of interleukin-36γ protein was enhanced by adenosine 5'-triphosphate. Furthermore, extracellular interleukin-36γ protein detection was markedly enhanced by sonication to disrupt membrane-bound structures. Interleukin-36γ protein was detected by Western blot in microparticles and exosome fractions isolated by ultracentrifugation. Interleukin-36γ was induced and secreted from lung macrophages in response to Gram-negative and -positive bacterial stimulation. The results suggest that interleukin-36γ is secreted in a non-Golgi-dependent manner by lung macrophages in response to Gram-positive and -negative bacterial challenge.
Objective:
Interleukin (IL)-36R signalling plays a proinflammatory role in different organs including the skin, but the expression of IL-36R ligands and their molecular function in intestinal inflammation are largely unknown.
Design:
We studied the characteristics of IL-36R ligand expression in IBDs and experimental colitis. The functional role of IL-36R signalling in the intestine was addressed in experimental colitis and wound healing models in vivo by using mice with defective IL-36R signalling (IL-36R-/-) or Myd88, neutralising anti-IL-36R antibodies, recombinant IL-36R ligands and RNA-seq genome expression analysis.
Results:
Expression of IL-36α and IL-36γ was significantly elevated in active human IBD and experimental colitis. While IL-36γ was predominantly detected in nuclei of the intestinal epithelium, IL-36α was mainly found in the cytoplasm of CD14(+) inflammatory macrophages. Functional studies showed that defective IL-36R signalling causes high susceptibility to acute dextran sodium sulfate colitis and impairs wound healing. Mechanistically, IL-36R ligands released upon mucosal damage activated IL-36R(+) colonic fibroblasts via Myd88 thereby inducing expression of chemokines, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-6. Moreover, they induced proliferation of intestinal epithelial cells (IECs) and expression of the antimicrobial protein lipocalin 2. Finally, treatment of experimental intestinal wounds with IL-36R ligands significantly accelerated mucosal healing in vivo.
Conclusions:
IL-36R signalling is activated upon intestinal damage, stimulates IECs and fibroblasts and drives mucosal healing. Modulation of the IL-36R pathway emerges as a potential therapeutic strategy for induction of mucosal healing in IBD.
Background:
Interleukin (IL)-36 (IL-36α, IL-36β, and IL-36γ) is a recently reported member of the IL-1 cytokine family. In this study, we investigated IL-36 expression in the inflamed mucosa of patients with inflammatory bowel disease and characterized the proinflammatory actions of IL-36 cytokines in human colonic epithelial cells.
Methods:
IL-36 mRNA expression was evaluated using real-time PCR. IL-36 protein expression was analyzed using immunoblotting and immunohistochemical technique. Intracellular signaling pathways were evaluated by immunoblotting and by specific siRNA-transfected cells.
Results:
The mRNA expression of IL-36α and IL-36γ, but not of IL-36β, was enhanced in the inflamed mucosa of patients with inflammatory bowel disease, in particular, in ulcerative colitis. Immunohistochemical analysis showed that T cells, monocytes, and plasma cells are the source of IL-36α and IL-36γ in colonic mucosa. DNA microarray analysis indicated that IL-36α induces the mRNA expression of CXC chemokines and acute phase proteins in intestinal epithelial cell line, HT-29 cells. IL-36α and IL-36γ dose-dependently and time-dependently induced the mRNA and protein expression of CXC chemokines (CXCL1, CXCL2, CXCL3 etc.) in HT-29 and Widr cells. Stimulation with IL-36α and IL-36γ assembled MyD88 adaptor proteins (MyD88, TRAF6, IRAK1, and TAK1) into a complex and induced the activation of NF-κB and AP-1 and also the phosphorylation of MAPKs. MAPK inhibitors and siRNAs specific for NF-κB and c-Jun AP-1 significantly reduced IL-36-induced CXC chemokine expression.
Conclusions:
IL-36α and IL-36γ may play a proinflammatory role in the pathophysiology of inflammatory bowel disease through induction of CXC chemokines and acute phase proteins.
Generalized pustular psoriasis is a severe skin disease characterized by epidermal hyperplasia, neutrophil rich abscesses within the epidermis and a mixed inflammatory infiltrate in the dermis. The disease may be caused by missense mutations in the interleukin-36 receptor antagonist, IL-36 Ra. Curiously, the related IL-1Ra has therapeutic effects in some of these latter patients. Here, using an experimental mouse model of psoriasiform skin inflammation, we demonstrate in vivo connections between IL-36 and IL-1 expression. After disease initiation IL-36α deficient mice exhibited dramatically diminished skin pathology, including absence of epidermal neutrophils, reduced keratinocyte acanthosis, and less dermal edema. In contrast, IL-36β and IL-36γ knockout mice developed disease indistinguishable from that of wild type mice. The endogenous IL-36α was not processed through proteolysis. While IL-36α expression was strongly induced in an IL-1 signaling-dependent manner during disease, expression of IL-1α was also dependent upon IL-36α. Hence, after being up-regulated by IL-1α, IL-36α acts through a feedback mechanism to boost IL-1α levels. Analyses of double knockout mice further revealed that IL-36α and IL-1α co-operate to promote psoriasis-like disease. In conclusion, IL-1α and IL-36α form a self-amplifying inflammatory loop in vivo that in patients with insufficient counter regulatory mechanisms may become hyper-engaged and/or chronic.Journal of Investigative Dermatology accepted article preview online, 23 July 2015. doi:10.1038/jid.2015.289.
We show that IL-36α induced maturation of human MDDCs and stimulated differentiation of IFN-γ producing (Type 1) CD3+ lymphocytes but was not as effective as IL-36β in doing so. For the first time, we also show that IL-36α induced expression of CD14 by MDDCs and this was highly potentiated by co-cultured with IFN-γ. In contrast, lipopolysaccharide (LPS) did not increase CD14 expression by MDDCs, suggesting that if MDDCs represent a physiologically relevant population in vivo, they need to be stimulated by relevant inflammatory cytokines prior to CD14 expression and detection of LPS, expressed by Gram negative bacteria. IFN-γ synergised with IL-36α to restore the high levels of CD11c expression by MDDCs, which was reduced by culture with these cytokines in isolation. IL-36α/IFN-γ synergy also correlated with increased binding of the opsonic complement protein (iC3b) to MDDCs. However although IL-36α increased the phagocytic capacity of MDDCs for Salmonella Typhimurium 4/74 this was not synergistically increased by IFN-γ (P>0.05). In conclusion we report the hitherto unknown effects of IL-36α on the innate cell function of human MDDCs.
Copyright © 2015 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.
Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has the unique potential to deliver insights into gene function. Here, we report two founder mutations (c.11T>G [p.Phe4Cys] and c.97C>T [p.Arg33Trp]) in AP1S3, the gene encoding AP-1 complex subunit σ1C, in 15 unrelated individuals with a severe autoinflammatory skin disorder known as pustular psoriasis. Because the variants are predicted to destabilize the 3D structure of the AP-1 complex, we generated AP1S3-knockdown cell lines to investigate the consequences of AP-1 deficiency in skin keratinocytes. We found that AP1S3 silencing disrupted the endosomal translocation of the innate pattern-recognition receptor TLR-3 (Toll-like receptor 3) and resulted in a marked inhibition of downstream signaling. These findings identify pustular psoriasis as an autoinflammatory phenotype caused by defects in vesicular trafficking and demonstrate a requirement of AP-1 for Toll-like receptor homeostasis.
The interleukin (IL)-1 family includes 11 members that are important in inflammatory processes. It includes various agonists and two antagonists, IL-1Ra and IL-36Ra. Our aim was to investigate whether the IL-1 family is involved in allergic contact dermatitis (ACD). The expression of IL-1 family members was evaluated by PCR and immunohistochemistry in the positive patch test reaction site (involved skin), and in the uninvolved skin of ACD patients. We also examined these cytokines in an ex vivo model of ACD. The antagonistic activity of IL-36Ra was evaluated by injecting recombinant IL-36Ra in uninvolved skin biopsies of ACD patients. IL-1Ra and IL-36Ra expression was quantified in mononuclear cells of nickel-sensitized patients challenged in vitro with nickel. IL33-involvement in ACD was investigated by intradermal injection of anti-IL-33 in the uninvolved skin of patients ex vivo. Results showed that IL-1β, IL-1Ra, IL-36α, IL-36β, IL-36γ and IL-33 expression, but not IL-36Ra expression was enhanced in ACD-involved skin. Immunohistochemical analysis and ex vivo skin cultures confirmed these results. Injection of anti-IL-33 in ACD-uninvolved skin inhibited IL-8 expression, whereas IL-36Ra inhibited IL-36α, IL-36β, IL-36γ and IL-8 expression. Nickel induced IL-1Ra expression in lymphocytes of nickel-sensitized patients. Hence, various IL-1 agonists and antagonists may be involved in ACD pathogenesis. This article is protected by copyright. All rights reserved.
IL-36 alpha (IL-1F6), IL-36 beta (IL-1F8), and IL-36 gamma (IL-1F9) are members of the IL-1 family of cytokines. These cytokines bind to IL-36R (IL-1Rrp2) and IL-1RAcP, activating similar intracellular signals as IL-1, whereas IL-36Ra (IL-1F5) acts as an IL-36R antagonist (IL-36Ra). In this study, we show that both murine bone marrow-derived dendritic cells (BMDCs) and CD4(+) T lymphocytes constitutively express IL-36R and respond to IL-36 alpha, IL-36 beta, and IL-36 gamma. IL-36 induced the production of proinflammatory cytokines, including IL-12, IL-1 beta, IL-6, TNF-alpha, and IL-23 by BMDCs with a more potent stimulatory effect than that of other IL-1 cytokines. In addition, IL-36 beta enhanced the expression of CD80, CD86, and MHC class II by BMDCs. IL-36 also induced the production of IFN-gamma, IL-4, and IL-17 by CD4(+) T cells and cultured splenocytes. These stimulatory effects were antagonized by IL-36Ra when used in 100-to 1000-fold molar excess. The immunization of mice with IL-36 beta significantly and specifically promoted Th1 responses. Our data thus indicate a critical role of IL-36R ligands in the interface between innate and adaptive immunity, leading to the stimulation of T helper responses. (Blood. 2011;118(22):5813-5823)
Formerly called IFN-gamma-inducing factor, IL-18 is the new name of a novel cytokine that plays an important role in the TH1 response, primarily by its ability to induce IFN-gamma production in T cells and natural killer cells. Mice deficient in IL-18 have suppressed IFN-gamma production despite the presence of IL-12. IL-18 is related to the IL-1 family in terms of both structure and function. In terms of structure, IL-18 and IL-1beta share significant primary amino acid sequences and are similarly folded as all-beta pleated sheet molecules. Also similar to IL-1beta, IL-18 is synthesized as a biologically inactive precursor molecule lacking a signal peptide. Studies have shown that similar to the IL-1beta precursor, the IL-18 precursor requires cleavage into an active, mature molecule by the intracellular cysteine protease called IL-1beta-converting enzyme (ICE), which is also known as caspase-1. Therefore inhibitors of ICE activity may limit the biologic activity of IL-18 and may be useful as TH1 immunosuppressive agents. The activity of mature IL-18 is closely related to that of IL-1. IL-18 induces gene expression and synthesis of TNF, IL-1, Fas ligand, and several chemokines. The activity of IL-18 is by means of a signaling chain of a putative IL-18 receptor (IL-18R) complex. This IL-18R complex is made up of a binding chain termed IL-18Ralpha, a member of the IL-lR family previously identified as the IL-1R-related protein (IL-1Rrp), and a signaling chain, the IL-18Rbeta, also a member of the IL-1R family. The IL-18R complex recruits IL-1R-activating kinase and TNF receptor-associated factor-6, which phosphorylates nuclear factor kappaB (NFkappaB)-inducing kinase with subsequent activation of NFkappaB. Thus on the basis of primary structure, 3-dimensional structure, receptor family, signal transduction pathways, and biologic effects of IL-18 appear to place this cytokine in the IL-1 family. Similar to IL-1, IL-18 participates in both innate and acquired immunity.
IL-18 — a novel cytokine with potent IFN-γ-inducing activities — plays an important role in the Th1-mediated immune response in collaboration with IL-12. IL-18 is a member of the IL-1 family. The IL-18 receptor system and its signal transduction pathway are analogous to those of the IL-1 receptor. Mice deficient in IL-18 have demonstrated its critical role in natural killer cell activity and in vivo Th1 response.
Background:
Generalized pustular psoriasis (GPP) is a chronic autoimmune disease characterized by fever, erythema, and neutrophilic pustules over large areas of the skin. GPP does not respond well to pharmacologic intervention.
Objective:
We sought to assess efficacy of selectively depleting the myeloid lineage leukocytes in patients with GPP.
Methods:
Fifteen patients with persistent moderate to severe GPP despite conventional therapy were included. Eligible patients had more than 10% of their skin area covered by pustules. Treatment with oral etretinate, cyclosporine, methotrexate, prednisolone, and topical prednisolone/vitamin D3 was continued if had been initiated well in advance of study entry. Five sessions of adsorptive granulocyte and monocyte apheresis (GMA) with the Adacolumn (JIMRO Co Ltd, Takasaki, Japan) were administered (1 session/wk over 5 weeks) to selectively deplete Fcγ receptor and complement receptor bearing leukocytes. Efficacy was assessed by measuring the skin areas covered by pustules at baseline and 2 weeks after the last GMA session.
Results:
One patient did not complete the first GMA session. Based on the GPP severity scores relative to entry, the overall scores improved (n = 14, P = .0027), and the area of erythroderma (P = .0042), pustules (P = .0031), and edema (P = .0014) decreased. Likewise, Dermatology Life Quality Index improved (P = .0016), reflecting better daily function and quality of life. Twelve patients were judged as responders (85.7%), and 10 patients maintained the clinical response for 10 weeks after the last GMA session without any change in medication.
Limitations:
This study was unblinded and without a placebo arm.
Conclusion:
GMA in this clinical setting was safe and effective, suggested a major role for granulocytes/monocytes in the immunopathogenesis of GPP.
Background Interleukin (IL)-36α is a recently described member of the IL-1 cytokine family with pro-inflammatory and clearly pathogenic properties in psoriasis.
Objective To determine the IL-36α expression in psoriatic arthritis (PsA) compared to rheumatoid arthritis (RA) and osteoarthritis (OA).
Methods Synovial tissues obtained from arthritis patients were stained for IL-36α, IL-36 receptor (IL-36R) and IL-36R antagonist (IL-36Ra) by immunohistochemistry and immunofluorescence. Lysates were examined for IL-36α by western blot analysis. Synovial fibroblasts (FLS) cultured in the presence of IL-36α were assayed for cytokine expression by quantitative real time PCR and multiplex assay. IL-36α-induced signal transduction in FLS was analysed by immunoblotting.
Results Expression of IL-36R and its ligands IL-36α and IL-36Ra was detected in the synovial lining layer and cellular infiltrates of patients with inflammatory arthritis. IL-36α was expressed significantly higher in PsA and RA than in OA synovium. CD138-positive plasma cells were identified as the main cellular source of IL-36α. No differences were observed for the expression of IL-36R and IL-36Ra between PsA, RA and OA. Functionally, IL-36α induced the expression of IL-6 and IL-8 in FLS through p38/NFkB activation.
Conclusions IL-36α is up-regulated in PsA and RA synovium, expressed by tissue plasma cells and leads to IL-6 and IL-8 production by synovial fibroblasts. Hence, IL-36α links plasma cells to inflammatory cytokine production by FLS and may represent a key link between autoimmunity and the induction of synovitis.
IL-1 drives T-helper responses, particularly Th17, in host defense. Sharing the same co-receptor, the IL-1 family member IL-36 exhibits properties similar to those of IL-1. In the present study, we investigated the role of IL-36 in Aspergillus fumigatus-induced human T-helper cell responses. We observed that different morphological forms of A. fumigatus variably increase steady-state mRNA of IL-36 subfamily members. IL-36α is not significantly induced by any morphological form of Aspergillus. Most strikingly, IL-36γ is significantly induced by live A. fumigatus conidia and heat killed hyphae, whereas IL-36Ra is significantly induced by heat killed conidia, hyphae and live conidia. We also observed that IL-36γ expression is dependent on the dectin-1/Syk and TLR4 signaling pathway. In contrast, TLR2 and CR3 inhibit IL-36γ expression. The biological relevance of IL-36 induction by Aspergillus is demonstrated by experiments showing that inhibition of the IL-36 receptor by IL-36Ra reduces Aspergillus-induced IL-17 and IFN-γ. These data describe that IL-36-dependent signals are a novel cytokine pathway that regulates T-helper responses induced by A. fumigatus, and demonstrate a role for TLR4 and dectin-1 in the induction of IL-36γ.
The interleukin-1 (IL-1) superfamily of cytokines comprises a set of pivotal mediators of inflammation. Among them, the action of IL-36 cytokines in immune responses has remained elusive. In a recent study, we demonstrated a direct effect of IL-36 on immune cells. Here we show that, among T cells, the IL-36 receptor is predominantly expressed on naive CD4(+) T cells and that IL-36 cytokines act directly on naive T cells by enhancing both cell proliferation and IL-2 secretion. IL-36β acts in synergy with IL-12 to promote Th1 polarization and IL-36 signaling is also involved in mediating Th1 immune responses to Bacillus Calmette-Guerin infection in vivo. Our findings point toward a critical function of IL-36 in the priming of Th1 cell responses in vitro, and in adaptive immunity in a model of mycobacterial infection in vivo.
Generalized pustular psoriasis (GPP) is a rare, potentially life threatening, and aggressive form of psoriasis, which is characterized by sudden onset with repeated episodic skin inflammation leading to pustule formation. Familial GPP is known to be caused by recessively inherited mutations in the IL36RN gene, which encodes interleukin 36 receptor antagonist (IL-36Ra). In this article, we performed mutation analysis of the IL36RN gene in 14 Japanese patients with GPP, and identified mutations in two of these patients analyzed. One patient was compound heterozygous for mutations c.115+6T>C and c.368C>G (p.Thr123Arg), whereas the other carried compound heterozygous mutations c.28C>T (p.Arg10*) and c.115+6T>C in the IL36RN gene. Expression studies using total RNA from the patients' skin revealed that the mutation c.115+6T>C resulted in skipping of exon 3, leading to a frameshift and a premature termination codon (p.Arg10Argfs*1). The protein structure analysis suggested that the missense mutation p.Thr123Arg caused misfolding and instability of IL-36Ra protein. In vitro studies in cultured cells showed impaired expression of the p.Thr123Arg mutant IL-36Ra protein, which failed to antagonize the IL-36 signaling pathway. Our data further underscore the critical role of IL36RN in pathogenesis of GPP.
Analysis of the human genome sequence and other DNA databases is proceeding at a rapid pace, and immunologists are playing an important role in the effort to ascribe functions to putative gene products. An excellent, recent example is the description of six gene sequences predicted to encode homologs of interleukin-1 (IL-1), named IL-1F5–IL-1F10. Indications of a possible role for these homologs in immunity and inflammation are starting to emerge. Most are expressed in monocytes, macrophages and/or dendritic cells; IL-1F5 and IL-1F9 are expressed strongly in keratinocytes; and the expression of IL-1F9 is induced in skin during contact hypersensitivity and in psoriasis patients. IL-1F7 and IL-1F10 bind to the soluble type I IL-1 receptor (IL-1RI) and IL-18R, respectively. Specific functions for these proteins are currently being sought.