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Function and Activation of NF-Kappa B in the Immune System
Abstract
NF-kappa B is a ubiquitous transcription factor. Nevertheless, its properties seem to be most extensively exploited in cells of the immune system. Among these properties are NF-kappa B's rapid posttranslational activation in response to many pathogenic signals, its direct participation in cytoplasmic/nuclear signaling, and its potency to activate transcription of a great variety of genes encoding immunologically relevant proteins. In vertebrates, five distinct DNA binding subunits are currently known which might extensively heterodimerize, thereby forming complexes with distinct transcriptional activity, DNA sequence specificity, and cell type- and cell stage-specific distribution. The activity of DNA binding NF-kappa B dimers is tightly controlled by accessory proteins called I kappa B subunits of which there are also five different species currently known in vertebrates. I kappa B proteins inhibit DNA binding and prevent nuclear uptake of NF-kappa B complexes. An exception is the Bcl-3 protein which in addition can function as a transcription activating subunit in th nucleus. Other I kappa B proteins are rather involved in terminating NF-kappa B's activity in the nucleus. The intracellular events that lead to the inactivation of I kappa B, i.e. the activation of NF-kappa B, are complex. They involve phosphorylation and proteolytic reactions and seem to be controlled by the cells' redox status. Interference with the activation or activity of NF-kappa B may be beneficial in suppressing toxic/septic shock, graft-vs-host reactions, acute inflammatory reactions, acute phase response, and radiation damage. The inhibition of NF-kappa B activation by antioxidants and specific protease inhibitors may provide a pharmacological basis for interfering with these acute processes.
... NF-κB family members regulate the transcription of cytokines and antimicrobial effectors. They also control cellular differentiation, survival and proliferation, thereby influencing innumerable facets of innate and adaptive immune responses [54]. signalling proteins, which have been known as the central immunomodulator of PAMPinduced proinflammatory cytokine production, were also found to be significantly enriched in the BM EV samples (Figure 4a) [47][48][49]. ...
... NF-κB family members regulate the transcription of cytokines and antimicrobial effectors. They also control cellular differentiation, survival and proliferation, thereby influencing innumerable facets of innate and adaptive immune responses [54]. ...
Milk is a complex biological fluid that has high-quality proteins including growth factors and also contains extracellular vesicles (EVs). EVs are a lipid bilayer containing vesicles that contain proteins, metabolites and nucleic acids. Several studies have proposed that EVs in cow milk can survive the gut and can illicit cross-species communication in the consuming host organism. In this study, we isolated and characterized extracellular vesicles from the raw milk of the four species of the Bovidae family, namely cow, sheep, goat and buffalo, that contribute 99% of the total milk consumed globally. A comparative proteomic analysis of these vesicles was performed to pinpoint their potential functional role in health and disease. Vesicles sourced from buffalo and cow milk were particularly enriched with proteins implicated in modulating the immune system. Furthermore, functional studies were performed to determine the anti-cancer effects of these vesicles. The data obtained revealed that buffalo-milk-derived EVs induced significantly higher cell death in colon cancer cells. Overall, the results from this study highlight the potent immunoregulatory and anti-cancer nature of EVs derived from the milk of Bovidae family members.
... 4,12 Vitamin C likely inhibits the activation of the nuclear transcription factor kB (NF-kB), which regulates the expression of a variety of inflammation-relevant genes and thus plays a decisive role in inflammatory reactions. 1,3,4,11 The inhibition of NF-kB by vitamin C is not only an antioxidant effect, because activation of redoxinsensitive pathways is prevented as well. 4 We therefore hypothesized that vitamin C may be valuable in the prevention of secondary frozen shoulder due to its anti-inflammatory effects by inhibition of NF-kB. ...
... Vitamin C might interfere in this pathway by buffering the oxidants 4,12 and by preventing the activation of NF-kB, which is a crucial regulator of inflammation. 1,3,4,11 To the best of our knowledge, no literature is available regarding the use of vitamin C in frozen shoulder. This surprised us very much, especially because vitamin C in a dosage up to 1000 mg/d is already listed in patient brochures of several Swiss clinics as part of the treatment of frozen shoulder. ...
Background:
Frozen shoulder is a common, painful, and movement-restricting condition. Although primary frozen shoulder is idiopathic, secondary frozen shoulder can occur after trauma or surgery. Prophylactic and therapeutic options are often unsatisfactory. Vitamin C (ascorbic acid) is a potent physiological antioxidant and likely inhibits the activation of nuclear factor κB, which plays a decisive role in inflammatory reactions.
Hypothesis:
Because of its anti-inflammatory effects, vitamin C may be valuable in the prevention of secondary frozen shoulder.
Study design:
Controlled laboratory study.
Methods:
An in vivo shoulder contracture model was conducted by fixation of the right proximal limb of Sprague-Dawley rats. A treatment group (n = 8) receiving vitamin C orally was compared with a control group (n = 9) without vitamin C. The primary outcome was capsular thickness at the shoulder joint measured on magnetic resonance imaging (MRI) examination. Further histological examination was performed but was not statistically analyzed because of variability of the cutting plane through the glenoid.
Results:
Vitamin C treatment resulted in less thickening of the axillary fold of the operated shoulder at 2 of the 3 locations measured on MRI compared with untreated controls (insertion to the glenoid, P = .074; insertion to the humerus, P = .006; middle of the axillary recess, P = .008). The observed structural changes in histological examination corroborated the significant changes obtained from the MRI measurements.
Conclusion:
Prophylactic vitamin C seemed to reduce the thickening of the axillary recess in secondary frozen shoulder in this preclinical study.
Clinical relevance:
Vitamin C may be helpful as a noninvasive therapeutic measure to prevent secondary frozen shoulder (eg, within the context of surgery in the shoulder region or immobilization) or to treat primary frozen shoulder at an early stage. Further studies are required to evaluate the effect of this treatment in humans and the necessary dosage in humans.
... The activation of LPS-induced macrophages produces proinflammatory cytokines, such as IL-1, TNF-α, IL-6, and IFN-γ and induces MAPK-dependent phosphorylation of p38, c-Jun NH2-terminal kinase (JNK), and ERK (28)(29)(30). Additionally, NF-κB is a major activator for the TNF-α production in macrophages and is known to play a major role in controlling the expression of proteins involved in immune, inflammatory, and acute-phase responses (30)(31)(32). MAPK and NF-κB signaling play critical roles in the immune response (28)(29)(30)(31)(32). A previous study reported that several natural products could show immune enhancement by activating the phosphorylation of inducible Nitric Oxide Synthase (iNOS), cyclooxygenase-2 (COX-2), NF-κB, and MAPKs (JNK, ERK, and p38) in RAW-264.7 cells (17,(33)(34)(35). ...
... Additionally, NF-κB is a major activator for the TNF-α production in macrophages and is known to play a major role in controlling the expression of proteins involved in immune, inflammatory, and acute-phase responses (30)(31)(32). MAPK and NF-κB signaling play critical roles in the immune response (28)(29)(30)(31)(32). A previous study reported that several natural products could show immune enhancement by activating the phosphorylation of inducible Nitric Oxide Synthase (iNOS), cyclooxygenase-2 (COX-2), NF-κB, and MAPKs (JNK, ERK, and p38) in RAW-264.7 cells (17,(33)(34)(35). ...
Background:
Euonymus alatus (Thunb.) Siebold (EA) is a medicinal plant used in some Asian countries to treat various diseases, including cancer, hyperglycemia, diabetes, urticaria, dysmenorrhea, and arthritis. Owing to the wide range of pharmacological applications of EA, various roles of EA are being studied.
Objective:
We evaluated the immune-enhancing effect of EA treatment in a cyclophosphamide (Cy)-induced immunosuppressed rat model.
Design:
We analyzed the immune enhancement effect of EA on macrophages by western blotting. In addition, cell viability and natural killer (NK) cell activity were analyzed in splenocytes following EA treatment. For in vivo studies, analysis of weekly body weight, spleen weight, immune cell count, cytokine levels, and spleen histological findings was performed following EA administration in Cy-induced immunocompromised rats.
Results:
EA significantly increased cell viability and phospho-nuclear factor-kappa B and phospho-extracellular signal-regulated kinase protein levels in the macrophages. EA significantly increased NK cell activity in splenocytes compared with the control group. In Cy-induced immunosuppressed rats, EA administration increased spleen tissue weight and the contents of leukocytes, lymphocytes, granulocytes, intermediate cells, and plasma cytokines (tumor necrosis factor-α and interferon-γ). In addition, improvement in the damaged spleen tissue was observed.
Conclusions:
These findings confirm that EA exerts an immune-enhancing effect, thereby suggesting its potential as an immunostimulatory agent or functional food.
... NF-κB primarily exists in the cytoplasm as a p50-p65 dimer and combines with inhibitory protein factor kappa B alpha (IκB-α). When RAW 264.7 cells are stimulated by LPS, IκB-α is phosphorylated and inactivated by IκB kinase, and subsequently, the activated p50-p65 dimer translocates into the nucleus, inducing the transcription of the corresponding target sequence and playing a role in secreting pro-inflammatory mediators [34][35][36][37]. The effective inhibition of the NF-κB pathway is one of the mechanisms by which numerous NSAIDs, such as aspirin, sulindac, tolfenamic, celecoxib, indomethacin, and ibuprofen, exert anti-inflammatory effects [38,39]. ...
Adenosma buchneroides Bonati, also known as fleagrass, is an important medicinal plant used by the Akha (Hani) people of China for treating inflammation-related skin swelling, acne, and diarrhoea, among other conditions. In this study, we aimed to evaluate the anti-inflammatory activities and explore the molecular mechanisms of fleagrass on treating skin swelling and acne. The results demonstrated that fleagrass inhibited the enzymatic activities of 5-LOX and COX-2 in vitro, and decreased the release of NO, IL-6, TNF-α, and IL-10 in the LPS-induced RAW264.7 macrophages. The levels of proteins associated with the nuclear factor-kappa B (NF-κB) pathway were examined by western blotting and immunofluorescence, demonstrating that fleagrass downregulated the expression of TLR4, MyD88, NF-κB/p65, and iNOS and blocked the nuclear translocation of NF-κB/p65. Furthermore, fleagrass exhibited acute anti-inflammatory activity in paw oedema models. The results confirm that fleagrass exhibits remarkable anti-inflammatory activity and can be used in alleviating inflammation, suggesting that fleagrass has the potential to be a novel anti-inflammatory agent.
Graphical Abstract
... 9 Among the NF-κB family of transcription factors, NFKB2 (p100/p52) is proteolytically cleaved in the proteasome to produce p52, which then binds Rel proteins to form heterodimeric complexes that bind DNA and regulate the transcription of genes necessary for inflammatory and immune responses. 10,11 Elevated expression levels of NFKB2 and the activation of the alternative pathway of NF-κB have been confirmed in non-small cell lung cancer, breast cancer, prostate tumors, and several cancer cell lines. [12][13][14][15] The activation of NF-κB pathways has been associated with unfavorable prognosis, indicating components within these pathways as potential prognostic markers or therapeutic targets for malignancies. ...
This study systematically analyzed the molecular mechanism and function of nuclear factor kappa B subunit 2 (NFKB2) in colorectal cancer (CRC) to investigate the potential of NFKB2 as a therapeutic target for CRC. Various experimental techniques, including RNA sequencing, proteome chip assays, and small molecule analysis, were used to obtain a deeper understanding of the regulation of NFKB2 in CRC. The results revealed that NFKB2 was upregulated in a significant proportion of patients with advanced hepatic metastasis of CRC. NFKB2 played an important role in promoting tumor growth through CD8 ⁺ T‐cell exhaustion. Moreover, NFKB2 directly interacted with signal transducer and activator of transcription 2 (STAT2), leading to increased phosphorylation of STAT2 and the upregulation of programmed death ligand 1 (PD‐L1). Applying a small molecule inhibitor of NFKB2 (Rg5) led to a reduction in PD‐L1 expression and improved response to programmed death‐1 blockade‐based immunotherapy. In conclusion, the facilitated NFKB2‐STAT2/PD‐L1 axis may suppress immune surveillance in CRC and targeting NFKB2 may enhance the efficacy of immunotherapeutic strategies. Our results provide novel insights into the molecular mechanisms underlying the contribution of NFKB2 in CRC immune escape.
... In our study, LPS strongly induced IB and NF-B p65 phosphorylation in microglial cells and pretreatment with the ethanol extract of M. oleifera Lam leaves attenuated the level in a concentrationdependent manner. Several inflammatory stimuli, including bacterial LPS, activate the transcription factor NF-B in microglia [44], leading to the production of iNOS and other inflammatory cytokines [45,46]. In unstimulated cells, NF-B is retained in the cytosol in an inactive form as a homodimer or a heterodimer by binding to the inhibitory protein IBs. ...
Moringa oleifera Lam has been used as a medicinal plant in many Asian countries including Thailand. The plant has a variety of pharmacological effects such as antioxidant, anti-inflammation, hypolipidemic, anti-infection, anticancer, and antidiabetic. The leaves and young pods, which contain various nutritional compounds including proteins, fatty acids, and vitamins, are widely consumed. In this study, we investigated the effects of hexane, ethyl acetate, methanol and ethanol crude extracts of M. oleifera Lam leaves on the viability of microglial cells and on the lipopolysaccharide-induced microglial activation. which is widely used as a model for neuroinflammation. Our findings suggested that all of the crude extracts at concentrations ranging from 10–9 to 10–5 g/mL did not significantly affect the viability of microglial cells and exhibited similar effects. Subsequently, we focused on ethanol extract for investigation of the molecular mechanism involving neuroinflammation. We found that the ethanol extract of M. oleifera Lam leaves at the concentrations of 10–9 to 10–5 g/mL significantly reduced inducible nitric oxide synthase (iNOS) protein expression and nitric oxide (NO) production, accompanied by the reduction of phospho-NF-κB and phospho-IκBα expressions. The results suggested that the ethanol extract of M. oleifera Lam leaves reduced NO production through reduction of iNOS protein expression following the inhibition of NF-κB/IκBα signaling pathways. Our study underscored the therapeutic potential of M. oleifera Lam leaves extract in neurodegenerative diseases associated with neuroinflammation. HIGHLIGHTS The ethanol extract of M. oleifera Lam leaves dose-dependently reduced NO production in LPS-activated microglia The reduction in NO production correlated with the reduction in iNOS protein expression The extract inhibited the expression of NF-kB/I-kBα protein expression in a dose-dependent manner The ethanol extract of oleifera Lam leaves exhibited anti-inflammatory effect via the inhibition of NF-kB/I-kBα signaling pathway GRAPHICAL ABSTRACT
... NF-κB is a multi-functional transcription factor, which can be expressed in almost all types of cells and plays an important role in the inflammatory response [43,44]. At the molecular level, inflammation is regulated by a variety of factors, such as ICAM-1 (ICAM-1), IL-8, IL-1, IL-2, TNF-α/β and NF-κB [45]. ...
Introduction
This study aimed to explore the effect and molecular mechanism of Tetrandrine (Tet) onlipopolysaccharide (LPS)-induceduveitis andoptic nerve injury in vivo and in vitro.
Methods
Uveitis was induced by LPS injected into the hindlimb foot pad of Wistar rats and was intervened by retroeyeball injection of Tet (100 nM, 1 μM or 10 μM).The anterior segment inflammation was observed by slit lamp. Tunelassay was used to detect the survival state of ganglion cells and nuclear layers of inner and outer. The detection of characteristic markers in different activation states of glial cells were performed by qualitative and quantitative test of immunofluorescence and western blotting. Also, western blotting was used to detect the expression of inflammatory factors in retina and the activation of nuclear factor kappa B (NF-κB) signal pathway. Meanwhile, routine blood test and function of liver and renal were performed.
Results
The ciliary hyperemia was obvious, and the iris vessels were dilated and tortuous in rats with LPS-induced uveitis. Tet-pretreated obviously elieved these symptoms. In addition, the dilation and hyperemia in Tet group were alleviated compared with LPS group, and the inflammatory scores in Tetgroup were significantly lower than those of LPS group. TUNEL Staining showed that the number ofretinal ganglion cell (RGCs) in Tetgroup was slightly less than that in normal group, but significantly more than that in LPS group, and the cells arranged orderly. Besides, the number of apoptotic cells was significantly less than that in LPS group. Tet reduced LPS-activated gliocyte in a dose-dependent manner. Tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β, interferon gamma (γ-IFN) and IL-2 in retina were increased by LPS but decreased significantly viaTet-pretreatment. Moreover, LPS activate NF-κB signal pathway, while Tet efficiently inhibited this effect.Furthermore, injection of Tet did not damage theroutineblood, liver and kidney.
Conclusions
Retrobulbar injection of Tet significantly alleviatedLPS-induced uveitisand optic nerve injuryof rats by activating gliocyte and NF-κB signaling pathway.
... These pathways include the human immune response pathway, the IL-10 signaling pathway, the cell chemotaxis pathway, the granulocyte activation pathway, and the IL-17 signaling pathway. These enriched pathways are all related to the NF-κB kinase pathway (Baeuerle & Henkel, 1994;Dunn et al, 1994;Ferrè et al, 2010;Tamassia et al, 2010;Serasanambati & Chilakapati, 2016;Swaidani et al, 2019), which suggests that the down-regualtion of NF-κB may be at least one of the mechanisms by which loss of IL1R1 or IL1RAP1 leads to radiation resistance. These data also indicate that radiation treatment led to transcriptional up-regulation of a set of genes in an IL1R1-and IL1RAP-dependent manner, which may account for, at least in part, IL1R1/IL1RAP-mediated radiation sensitivity. ...
Radiation therapy (RT) is one of the most commonly used anticancer therapies. However, the landscape of cellular response to irradiation, especially to a single high-dose irradiation, remains largely unknown. In this study, we performed a whole-genome CRISPR loss-of-function screen and revealed temporal inherent and acquired responses to RT. Specifically, we found that loss of the IL1R1 pathway led to cellular resistance to RT. This is in part because of the involvement of radiation-induced IL1R1-dependent transcriptional regulation, which relies on the NF-κB pathway. Moreover, the mitochondrial anti-apoptotic pathway, particularly the BCL2L1 gene, is crucially important for cell survival after radiation. BCL2L1 inhibition combined with RT dramatically impeded tumor growth in several breast cancer cell lines and syngeneic models. Taken together, our results suggest that the combination of an apoptosis inhibitor such as a BCL2L1 inhibitor with RT may represent a promising anticancer strategy for solid cancers including breast cancer.
... Moreover, decreased levels of IL-6 have been reported after treatment with buthionine sulphoximine, a glutathione depletor, in rats [26]. As suggested in this study, the glutathione-regulated NF-kB transcription factor, which is reported to be involved in the production of cytokines such as IL-1b, IL-6, and TNF-a, could be responsible for the IL-6 decrease [26][27][28]. CRP is synthesized both in the liver, with the stimulation of IL-6 and TNF-α, and in adipose tissue. Several studies have reported the association between elevated CRP levels and PCOS [12,13,29]. ...
Objective
Comparison of hormonal, metabolic and inflammatory markers of glutathione with metformin and Diane-35 in a rat model of PCOS induced by dehydroepiandrosterone.
Methods
Twenty-five female rats were randomized into four groups. Group 1 was administered a subcutaneous dose of 0.2 ml saline/day. Group 2 was given 0.2 ml of 1% carboxymethyl cellulose (CMC)/day orally for 28 days. A PCOS model was established with DHEA in rats. Group 3 was given 4.5 mg/kg/day of Diane-35 orally dissolved in 1% CMC for 28 days. Group 4 was given 300 mg/kg/day of metformin orally dissolved in 1 ml of saline for 28 days, and Group 5 was administered 100 mg/kg of glutathione intraperitoneally on days 35, 42, and 49. On day 56, the rats were sacrificed. Serum markers and follicle count were examined.
Results
Serum IL-6, hs-CRP, insulin, testosterone, SHBG, and MDA values were significantly lower in the glutathione group than in the PCOS group (p = 0.0006, p = 0.023, p = 0.0082, p = 0.0007, p = 0.0048, and p < 0.0001, respectively).
The number of all follicles was similar between the control and glutathione groups (p < 0.05). When we compared the other groups with the PCOS group, the number of primary, secondary, atretic, and cystic follicles was significantly lower in the metformin and glutathione groups. The number of primordial and antral follicles was significantly higher than in the PCOS group.
Conclusions
Glutathione plays anti-inflammatory and antioxidant roles, similar to metformin, by lowering serum IL-6, insulin, testosterone, CRP, and MDA levels; decreasing atretic/cystic follicle count; and improving antral follicle count and folliculogenesis in PCOS patients.
... Transcription factors of the nuclear factor κB (NF-κB)/Rel family play a pivotal role in inflammatory and immune responses [46,47]. Zhao et al. demonstrated that overexpression of PBMC-derived cricGARS (hsa_circRNA_0009000) in SLE suppressed the expression of the ubiquitin editing enzyme A20 and facilitated the phosphorylation of p65 and IkBα [48], thereby activating NF-κB pathway-mediated immune inflammatory responses in SLE. ...
The outcomes and prognosis of autoimmune diseases depend on early diagnosis and effective treatments. However, symptoms of early autoimmune diseases are often remarkably similar to many inflammatory diseases, leading to difficulty in precise diagnosis. Circular RNAs (circRNAs) belong to a novel class of endogenous RNAs, functioning as microRNA (miRNA) sponges or participating in protein coding. It has been shown in many studies that patients with autoimmune diseases have aberrant circRNA expression in liquid biopsy samples (such as plasma, saliva, and urine). Thus, circRNAs are potential biomarkers for the diagnosis and prognosis of autoimmune diseases. Moreover, overexpression and depletion of target circRNAs can be utilized as possible therapeutic approaches for treating autoimmune diseases. In this review, we summarized recent progress in the roles of circRNAs in the pathogenesis of autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and type 1 diabetes. We also discussed their potential as biomarkers and therapeutic targets.
... In reality, blocking this receptor with a range of highly affine specific competitive antagonists, including ondansetron, tropisetron, granisetron, dolasetron, and others, has a number of advantageous therapeutic outcomes (33) . Over 200 genes, including those involved in the immunological response (36)(37) , inflammation (38) , differentiation, proliferation, cell survival, and apoptosis, are regulated by the transcription factor nuclear factor (NF)-κB (39,40) . This transcription factor's activation has been linked to the consequences of ionizing radiation exposure, and NF-κB is abnormally activated in many human disorders, including cancer and inflammatory conditions (36) . ...
... The NF-kB, as a transcription factor, is important in the production of various inflammatory mediators including but not limited to IL-1 and TNF-a. Furthermore, receptor activator of NF-kB ligand (RANKL)induced NF-kB activity in osteoclast precursors plays a role in osteoclastic differentiation [34,35]. Inhibition of the NF-kB pathway by celastrol [9,36] and other molecules [35] has been shown to ameliorate inflammatory bone diseases. ...
Introduction
Periodontitis is a common chronic inflammatory disease characterized by the destruction of the supporting structures of the teeth. The host defense mechanisms are responsible for inflamatuar and destructive reactions in periodontitis. Celastrol is one of the most promising components of the plant in Eastern and Southern China that has a long history of use in traditional medicine for the treatment of inflammatory conditions.
Aim
The aim of this animal study was to inspect the preventive or restrictive effects of celastrol on periodontitis-related inflammatory host response and alveolar bone loss.
Methods
24 male Sprague Dawley rats were randomly assigned into 3 groups: control, experimental periodontitis (Ep), and experimental periodontitis-celastrol (Ep-Cel). Periodontitis was induced by placing ligatures sub-paramarginally around the mandibular first molars of the rats in the Ep and Ep-Cel groups and maintaining the ligatures for 15 days. For 14 days following the ligature placement, celastrol administration (1 mg/kg BW day) for the Ep-Cel group and vehicle injection for the control and Ep groups was carried out. At the end of the experiment, mandibula and gingiva samples were obtained after the euthanasia. Alveolar bone loss was measured on serial histological slices; Tumor Necrosis Factor-α and Interleukin-1β levels were measured on gingiva samples by ELISA.
Results
Systemic celastrol administration significantly restricted the alveolar bone loss that was higher in rats with periodontitis. (p < 0.05) Tumor Necrosis Factor-α and Interleukin-1β levels that were high in the gingiva of the rats with periodontitis were found significantly lower in rats administered celastrol. (p < 0.05)
Conclusion
Celastrol restricted periodontitis-related alveolar bone loss by suppressing the inflammatory response.
... After I/R injury, Homer1a inhibits the NLRP3 inflammasome, but not the caspase-8 inflammasome, through the NF-κB P65 pathway NF-κB P65, which plays an important role in the inflammatory immune response, stimulates inflammasome formation and IL-1β and IL-18 secretion after activation (Baeuerle and Henkel, 1994;Baeuerle and Baltimore, 1996). NF-κB P65 expression in retinal tissue and Müller cells was examined at different time points. ...
JOURNAL/nrgr/04.03/01300535-202407000-00042/figure1/v/2023-11-20T171125Z/r/image-tiff
Elevated intraocular pressure (IOP) is one of the causes of retinal ischemia/reperfusion injury, which results in NLRP3 inflammasome activation and leads to visual damage. Homer1a is reported to play a protective role in neuroinflammation in the cerebrum. However, the effects of Homer1a on NLRP3 inflammasomes in retinal ischemia/reperfusion injury caused by elevated IOP remain unknown. In our study, animal models were constructed using C57BL/6J and Homer1 flox/ – /Homer1a +/ – /Nestin-Cre +/ – mice with elevated IOP-induced retinal ischemia/reperfusion injury. For in vitro experiments, the oxygen-glucose deprivation/reperfusion injury model was constructed with Müller cells. We found that Homer1a overexpression ameliorated the decreases in retinal thickness and Müller cell viability after ischemia/reperfusion injury. Furthermore, Homer1a knockdown promoted NF-κB P65 Ser536 activation via caspase-8, NF-κB P65 nuclear translocation, NLRP3 inflammasome formation, and the production and processing of interleukin-1β and interleukin-18. The opposite results were observed with Homer1a overexpression. Finally, the combined administration of Homer1a protein and JSH-23 significantly inhibited the reduction in retinal thickness in Homer1 flox/ – /Homer1a +/ – /Nestin-Cre +/ – mice and apoptosis in Müller cells after ischemia/reperfusion injury. Taken together, these studies demonstrate that Homer1a exerts protective effects on retinal tissue and Müller cells via the caspase-8/NF-κB P65/NLRP3 pathway after I/R injury.
... The cytokines in question enhance osteoclast activity while reducing osteoblastogenesis, which results in more bone loss. BPs and DENOS both affect receptor activator of nuclear factor kappa-Β ligand (RANKL), which in turn decreases the osteoclast activity [13]. The three most widely used BPs are zoledronic acid, pamidronate, and oral clodronate; however, clodronate is not authorized for usage in the US. ...
An aberrant growth of plasma cells in the bone marrow characterizes the hematological neoplasm known as multiple myeloma, which is typically accompanied by increased bone pain and skeletal-related events such as pathological fractures and/or spinal cord compression. Changes in the bone marrow microenvironment brought on by increased osteoclastic activity and/or decreased osteoblastic activity as a result of myeloma bone disease have a detrimental effect on quality of life. Bone-modifying medications such as bisphosphonates or denosumab are used to treat myeloma bone disease. These substances can lessen bone pain and the chance of pathological fracture, but they do not stimulate the growth of new bone or heal already damaged bone. In order to conduct this study, we searched the PubMed, Google Scholar, and Cochrane databases for complete free papers published in English and studied people over the previous five years, starting in 2018. The search covered randomized clinical trials (RCT), observational studies, meta-analyses, systemic reviews, and conventional reviews. Twenty-five publications are picked after using quality evaluation techniques to determine the type of study. These papers' full-text articles are investigated, examined, and tallied. We spoke about the various treatments for bone damage in multiple myeloma. It was discovered that bisphosphonates lessen the frequency and severity of bone problems. However, we are unsure of their contribution to survival.
Although these medicines enhance life quality, it is unknown if they also increase overall survival. The focus of this study is on several kinds of bone-modifying drugs, their processes of action, the point at which therapy is started, how long it lasts, and any possible mortality advantages.
... Research evidence has convincingly shown that the first line of protection against invading pathogens is innate immunity (Cameron et al., 2016). NF κB is a pleiotropic transcription factor involved in inflammatory and immune responses (Baeuerle and Henkel, 1994;Baeuerle and Baltimore, 1996). In the docking studies above, ECG active ingredients showed strong binding activity with the critical inflammatory target (RELA/p65). ...
... CXCR4 plays a crucial role in tumor development, proliferation, and metastasis mainly by contributing to the establishment of cancer stem-like cell supporting niches and the chemotactic directing of cancer cells to those microenvironments [82]. NF-κB has been suggested as a transcription factor regulating CXCR4 expression and it was shown that CXCR4 expression is dependent on the activation of the NF-κB pathway in several cancer types [83][84][85]. For instance, when human breast cancer cells with constitutive NF-κB activity were treated with NF-κB inhibitors, (overexpression of IκBα or parthenolide treatment), the expression of CXCR4 transcripts was notably reduced, followed by a loss of SDF-1α-mediated migration [86]. ...
NF-κB transcription factors are critical regulators of innate and adaptive immunity and major mediators of inflammatory signaling. The NF-κB signaling is dysregulated in a significant number of cancers and drives malignant transformation through maintenance of constitutive pro-survival signaling and downregulation of apoptosis. Overactive NF-κB signaling results in overexpression of pro-inflammatory cytokines, chemokines and/or growth factors leading to accumulation of proliferative signals together with activation of innate and select adaptive immune cells. This state of chronic inflammation is now thought to be linked to induction of malignant transformation, angiogenesis, metastasis, subversion of adaptive immunity, and therapy resistance. Moreover, accumulating evidence indicates the involvement of NF-κB signaling in induction and maintenance of invasive phenotypes linked to epithelial to mesenchymal transition (EMT) and metastasis. In this review we summarize reported links of NF-κB signaling to sequential steps of transition from epithelial to mesenchymal phenotypes. Understanding the involvement of NF-κB in EMT regulation may contribute to formulating optimized therapeutic strategies in cancer.
... Therefore, the regulation of SUR1 gene expression could depend on more than one mechanism. The NFκB factor is primarily associated with the onset of inflammatory responses and is a crucial contributor to the secondary damage of cerebral ischemia [48,49]. In post-mortem human brain samples from patients with cerebral ischemia, NFκB has been found active around the ischemic tissue up to 24 h after the damage began [50]. ...
The SUR1-TRPM4-AQP4 complex is overexpressed in the initial phase of edema induced after cerebral ischemia, allowing the massive internalization of Na⁺ and water within the brain micro endothelial cells (BMEC) of the blood-brain barrier. The expression of the Abcc8 gene encoding SUR1 depends on transcriptional factors that are responsive to oxidative stress. Because reactive oxygen species (ROS) are generated during cerebral ischemia, we hypothesized that antioxidant compounds might be able to regulate the expression of SUR1. Therefore, the effect of resveratrol (RSV) on SUR1 expression was evaluated in the BMEC cell line HBEC-5i subjected to oxygen and glucose deprivation (OGD) for 2 h followed by different recovery times. Different concentrations of RSV were administered. ROS production was detected with etidine, and protein levels were evaluated by Western blotting and immunofluorescence. Intracellular Na⁺ levels and cellular swelling were detected by imaging; cellular metabolic activity and rupture of the cell membrane were detected by MTT and LDH release, respectively; and EMSA assays measured the activity of transcriptional factors. OGD/recovery increased ROS production induced the AKT kinase activity and the activation of SP1 and NFκB. SUR1 protein expression and intracellular Na⁺ concentration in the HBEC-5i cells increased after a few hours of OGD. These effects correlated with cellular swelling and necrotic cell death, responses that the administration of RSV prevented. Our results indicate that the ROS/AKT/SP1-NFκB pathway is involved in SUR1 expression during OGD/recovery in BMEC of the blood-brain barrier. Thus, RSV prevented cellular edema formation through modulation of SUR1 expression.
... NF-κBp65 is an important transcription factor that controls inflammatory genes and is activated by cytokines and oxygen metabolites [21]. NF-κB activation appears to be a common factor in the expression of inflammation-associated prosurvival genes, such as Bcl-2, Bcl-x, and VEGF [22]. ...
Purpose:
Necrotizing enterocolitis (NEC) is a devastating disease that can cause mortality in preterm babies. NEC may develop through an apoptotic pathway that is known to be inhibited by vascular endothelial growth factor (VEGF). This study determined whether VEGF exerted a protective effect against the development of NEC and apoptosis in rats.
Methods:
To determine the effect of VEGF in NEC rats, neonatal rats were randomized into 4 groups: the control group, the NEC group, the NEC + intraperitoneal VEGF (50 ng/kg) group (NEC + VEGF IP group), and the NEC + oral VEGF (50 ng/kg) group (NEC + VEGF OR group). NEC was induced by lipopolysaccharide/hypoxia and cold stress. The animals were sacrificed 72 hours later. After laparotomy, we obtained a region of the proximal small bowel from the ileocecal valve about 18 cm in length.
Results:
The NEC histological grade, apoptosis histological score, and caspase-3 activity were lower in the NEC + VEGF IP and OR groups than in the NEC group. In the NEC + VEGF IP and OR groups, the messenger RNA expression of apoptotic and inflammatory genes, such as Bax, NF-κB, p53, Fas, FasL, and PAF-R, but not that of Bcl-2, was decreased, as was the Bax/Bcl-2 protein ratio. Histological analysis revealed that the apoptosis-blocking effect of VEGF was more effective in the NEC + VEGF IP group than in the NEC + VEGF OR group.
Conclusion:
We identified apoptotic and inflammatory genes to confirm the preventive effect of VEGF pretreatment on NEC in rats. This study presents a novel approach to prevent apoptosis via VEGF pretreatment in rats with lipopolysaccharide/hypoxia-induced NEC.
... The NF-kB pathway is implicated in controlling the pathogenesis of IDD [60], and its activation leads to enhanced expression of inflammatory factors and the degradation of ECM [61]. In contrast, the heterodimer P50-P65 is considered to be the most abundant form of NF-κB and has been shown to regulate the expression of many genes [62]. We selected the P65 gene for immunofluorescence detection, thus using it to assess the activation level of the NF-κB pathway. ...
Intervertebral disc degenerative disease (IDD), which usually causes lower back and neck pain, is one of the most widespread musculoskeletal disorders and often causes a low quality of life. However, the surgical and conservative treatments commonly used in clinical practice are not effective. Previous studies have identified curcumin (Cur) as a potential therapeutic agent. However, its development in this regard has been limited due to its low dissolution, instability in water, and rapid metabolism. In this study, we developed a novel anti-inflammatory composite hydrogel scaffold with curcumin encapsulated in solid lipid nanoparticles and mixed it with gelatin methacrylate (GelMA) hydrogel to treat IDD. The hydrogel scaffold, denoted Cur-solid lipid nanoparticles (SLNs)/GelMA, promoted the restoration of Collagen type II (Col II) and aggrecan expression levels in vivo, indicating that the regeneration of the intervertebral discs was effective. Combined in vitro studies showed that Cur-SLNs inhibited the expression of the inflammatory factors TNF-α and IL-6. Additionally, immunofluorescence and western blotting experiments verified that Cur-SLNs regulated the recovery of Col II and aggrecan in an inflammatory environment and promoted the metabolic homeostasis of the extramedullary cell matrix. In conclusion, this study provides a new strategy to promote IDD regeneration, which brings new application prospects. Article highlights • The combination of Cur encapsulated with SLNs and GelMA hydrogel in the treatment of IDD can reestablish the metabolic homeostasis of the pathologic process and reduce the inflammatory response. • This novel anti-inflammatory composite hydrogel scaffold can facilitate the repair of IDD and offers new perspectives for the treatment of IDD.
... Reactive oxygen species (ROS) toxicity underpins radiation therapy, which can harm macromolecules including DNA, RNA, microRNA, and proteins through a variety of pathways including lipid peroxidation and enzyme oxidation (24)(25)(26)(27)(28)(29) . Malondialdehyde is a biological marker for both oxidative stress and lipid peroxidation and is a sign of cellular damage (30,31) . Several studies assessing MDA levels in individuals after head and neck radiation found an increase (24,29,32). ...
Background: The development of neurotoxicity in healthy, non-targeted brain tissue
exposed to radiation during cranial radiotherapy (RT) is the most frequent event of
radiation-induced adverse effects. The 5-hydroxytryptamine-3 (5-HT3) receptor
antagonists may also have a range of neuroprotective, anti-inflammatory, and
antiphlogistic properties in addition to their anti-emetic effects. Materials and
Methods: Study groups were formed in the following ways: Group 2: Irradiation (IR)-
only (IR+Saline); Group 1: Normal control (orally fed control); Group 3: IR+Granisetron
(IR+Granisetron): whole-brain IR and Granisetron 1 mg/kg/day (Merck) administered
orally. 15 days of all therapies were given. The 15 days were completed with
behavioral testing. In the entire brain IR-only (placebo) group, a substantial
deterioration was seen in all studied marker levels and behavioral test results. Results:
Compared to the IR-only group, all of these biochemical indicators significantly
improved in the granisetron group (IR+Granisetron), and levels of the control group
returned to normal. In behavioral test analyses, a substantial decline in the open field
and passive avoidance learning social recognition tests was seen in the IR-only group
compared to the healthy control group, whereas an improvement was seen in the
IR+Granisetron group. In addition, the IR-only group showed a reduction in
hippocampus neurons and Purkinje neurons as well as an increase in hippocampal
gliosis, whereas the IR+Granisetron group showed an improvement and a return to
the normal control group counts. Conclusion: In summary, we discovered that
granisetron had neuroprotective properties in a rat model of radiation-induced brain
damage.
... NF-kB, a transcription factor known for its crucial role in regulating the expression of proinflammatory cytokines and other mediators [194][195][196][197][198], consists of homo-or heterodimers formed by five distinct Rel proteins: p65 (RELA), p50 (NF-kB1), p52 (NF-kB2), c-Rel, and RelB. In the absence of stimulation, NF-kB remains inactive in the cytoplasm, bound to inhibitory kB (IkB) proteins. ...
It is well known that the pineal gland in birds influences behavioural and physiological functions, including those of the immune system. The purpose of this research is to examine the endocrine–immune correlations between melatonin and immune system activity. Through a description of the immune–pineal axis, we formulated the objective to determine and describe: the development of the pineal gland; how light influences secretory activity; and how melatonin influences the activity of primary and secondary lymphoid organs. The pineal gland has the ability to turn light information into an endocrine signal suitable for the immune system via the membrane receptors Mel1a, Mel1b, and Mel1c, as well as the nuclear receptors RORα, RORβ, and RORγ. We can state the following findings: green monochromatic light (560 nm) increased serum melatonin levels and promoted a stronger humoral and cellular immune response by proliferating B and T lymphocytes; the combination of green and blue monochromatic light (560–480 nm) ameliorated the inflammatory response and protected lymphoid organs from oxidative stress; and red monochromatic light (660 nm) maintained the inflammatory response and promoted the growth of pathogenic bacteria. Melatonin can be considered a potent antioxidant and immunomodulator and is a critical element in the coordination between external light stimulation and the body’s internal response.
... The family of NF-κB (nuclear factor kappa-light chain-enhancer of activated B cells)/Rel transcription factors is activated by a broad range of environmental and endogenous cues, including viral and bacterial pathogen-associated molecular patterns (PAMPs) and cytokines [1,2]. The activated NF-κB pathways strongly drive immune and stress responses [3,4], as they direct inflammatory processes and cell growth, differentiation, and survival [5][6][7][8][9]. ...
NF-κB signalling is largely controlled by the family of ‘inhibitors of NF-κB’ (IκB). The relevant databases indicate that the genome of rainbow trout contains multiple gene copies coding for iκbα (nfkbia), iκbε (nfkbie), iκbδ (nkfbid), iκbζ (nfkbiz), and bcl3, but it lacks iκbβ (nfkbib) and iκbη (ankrd42). Strikingly, three nfkbia paralogs are apparently present in salmonid fish, two of which share a high sequence identity, while the third putative nfkbia gene is significantly less like its two paralogs. This particular nfkbia gene product, iκbα, clusters with the human IκBβ in a phylogenetic analysis, while the other two iκbα proteins from trout associate with their human IκBα counterpart. The transcript concentrations were significantly higher for the structurally more closely related nfkbia paralogs than for the structurally less similar paralog, suggesting that iκbβ probably has not been lost from the salmonid genomes but has been incorrectly designated as iκbα. In the present study, two gene variants coding for iκbα (nfkbia) and iκbε (nfkbie) were prominently expressed in the immune tissues and, particularly, in a cell fraction enriched with granulocytes, monocytes/macrophages, and dendritic cells from the head kidney of rainbow trout. Stimulation of salmonid CHSE-214 cells with zymosan significantly upregulated the iκbα-encoding gene while elevating the copy numbers of the inflammatory markers interleukin-1-beta and interleukin-8. Overexpression of iκbα and iκbε in CHSE-214 cells dose-dependently quenched both the basal and stimulated activity of an NF-κB promoter suggesting their involvement in immune-regulatory processes. This study provides the first functional data on iκbε—versus the well-researched iκbα factor—in a non-mammalian model species.
... These free NF-κB dimers enter the nucleus to bind to genes containing NF-κB binding sites and initiate the transcriptional process (Legrand-Poels et al., 1998). Additionally, NF-κB activates the expression of the I κBα gene, and newly synthesized I κBα re-inhibits NF-κB activity (Baeuerle and Henkel, 1994;Smale, 2012). NF-κB plays a crucial role in regulating cellular responses due to its ability to quickly activate as a master transcription factor without the need for new protein synthesis. ...
Background: Herbs originating from the Aconitum L. (Ranunculaceae), such as Aconitum carmichaelii Debeaux. (Wutou), Aconitum pendulum Busch. (Tiebangchui), and Aconitum kusnezoffii Reichb. (Caowu), etc. are highly valued for their medicinal properties. The roots and tubers of these herbs are commonly used to treat an array of ailments, including joint pain and tumors. The alkaloids present in them are the primary active components, with aconitine being the most notable. Aconitine has gained attention for its exceptional anti-inflammatory and analgesic properties, as well as its potential as an anti-tumor and cardiotonic agent. However, the exact process through which aconitine hinders the growth of cancerous cells and triggers their programmed cell death remains unclear. Therefore, we have undertaken a comprehensive systematic review and meta-analysis of the current research on the potential antitumor properties of aconitine.
Methods: We conducted a thorough search of relevant preclinical studies in databases including PubMed, Web of Science, VIP, WanFang Data, CNKI, Embase, Cochrane Library, and National Center for Biotechnology Information (NCBI). The search was conducted up until 15 September 2022, and the data were statistically analyzed using RevMan 5.4 software. The number of tumor cell value-added, tumor cell apoptosis rate, thymus index (TI), and Bcl-2 gene expression level were the main indicators to be analyzed.
Results: After applying the final inclusion criteria, a total of thirty-seven studies, comprising both in vivo and in vitro research were analyzed. The results showed that treatment with aconitine led to a significant reduction in tumor cell proliferation, a noteworthy increase in the rate of apoptosis among tumor cells, a decrease in the thymus index, and a reduction in the expression level of Bcl-2. These results suggested that aconitine could inhibit the proliferation, invasion, and migration abilities of tumor cells by regulating Bcl-2 etc., thereby enhancing the anti-tumor effects.
Conclusion: In summary, our present study demonstrated that aconitine effectively reduced tumor size and volume, indicating a strong anti-tumor effect. Additionally, aconitine could increase the expression levels of caspase-3, Bax and other targets. Mechanistically, it may regulate the expression levels of Bax and Bcl-2 through the NF-κB signaling pathway, ultimately inhibiting tumor cell proliferation through autophagy.
... The expression of pro-inflammatory cytokines, which perform a foremost function in the inflammatory responses of mammals and can be triggered by oxidative stress, is regulated by the NF-κB signaling pathway (Baeuerle and Henkel, 1994). In our study, we evaluated related gene expression levels in the NF-κB signaling pathway. ...
Deoxynivalenol (DON), as a widespread Fusarium mycotoxin in cereals, food products, and animal feed, is detrimental to both human and animal health. The liver is not only the primary organ responsible for DON metabolism but also the principal organ affected by DON toxicity. Taurine is well known to display various physiological and pharmacological functions due to its antioxidant and anti-inflammatory properties. However, the information regarding taurine supplementation counteracting DON-induced liver injury in piglets is still unclear. In our work, twenty-four weaned piglets were subjected to four groups for a 24-day period, including the BD group (a basal diet), the DON group (3 mg/kg DON-contaminated diet), the DON+LT group (3 mg/kg DON-contaminated diet + 0.3% taurine), and the DON+HT group (3 mg/kg DON-contaminated diet + 0.6% taurine). Our findings indicated that taurine supplementation improved growth performance and alleviated DON-induced liver injury, as evidenced by the reduced pathological and serum biochemical changes (ALT, AST, ALP, and LDH), especially in the group with the 0.3% taurine. Taurine could counteract hepatic oxidative stress in piglets exposed to DON, as it reduced ROS, 8-OHdG, and MDA concentrations and improved the activity of antioxidant enzymes. Concurrently, taurine was observed to upregulate the expression of key factors involved in mitochondrial function and the Nrf2 signaling pathway. Furthermore, taurine treatment effectively attenuated DON-induced hepatocyte apoptosis, as verified through the decreased proportion of TUNEL-positive cells and regulation of the mitochondria-mediated apoptosis pathway. Finally, the administration of taurine was able to reduce liver inflammation due to DON, by inactivating the NF-κB signaling pathway and declining the production of pro-inflammatory cytokines. In summary, our results implied that taurine effectively improved DON-induced liver injury. The underlying mechanism should be that taurine restored mitochondrial normal function and antagonized oxidative stress, thereby reducing apoptosis and inflammatory responses in the liver of weaned piglets.
... We evaluated hepatic inflammation by (1) immunohistochemistry for F4/80 (macrophage marker) [17] in paraffin-embedded liver sections (4-µm thick); slides were imaged by Digital Aperio AT2 scanner; the number of F4/ 80 positive cells were counted in three random fields (0.056 mm 2 per field) for each mouse, 3 different mice for each group; (2) immunoblots for phosphop-NF-κB (p65 subunit; NF-κB play a pivotal role in inflammatory and immune responses) [18] and NF-κB (p65 subunit) in 3 different total liver samples for each group to fit in the same gel; and (3) qPCR for IL-6, IL-1β, and TNF-alpha in 3 different total liver samples. Immunoblots were performed by standard techniques. ...
Background aims:
Secretin (SCT) and secretin receptors (SR, only expressed in cholangiocytes within the liver) play key roles in modulating liver phenotypes. Forkhead box A2 (FoxA2) is required for normal bile duct homeostasis by preventing excess of cholangiocyte proliferation. Short-term administration of the SR antagonist (SCT 5-27) decreased ductular reaction (DR) and liver fibrosis in bile duct ligated and Mdr2-/- (primary sclerosing cholangitis, PSC, model) mice. We aimed to evaluate the effectiveness and risks of long-term SCT 5-27 treatment in Mdr2-/- mice.
Approach results:
In vivo studies were performed in male wild-type (WT) and Mdr2-/- mice treated with saline or SCT 5-27 for 3 months and human samples from late-stage PSC patients and healthy controls. The biliary SCT/SR expression and SCT serum levels increased in Mdr2-/- mice and late-stage PSC patients compared to controls. There was a significant increase in DR, biliary senescence, liver inflammation, angiogenesis, fibrosis, biliary expression of TGF-β1/VEGF-A axis, and biliary phosphorylation of PKA and ERK1/2 in Mdr2-/- mice. The biliary expression of miR-125b and FoxA2 decreased in Mdr2-/- compared to WT mice, which was reversed by long-term SCT 5-27 treatment. In vitro, SCT 5-27 treatment of a human biliary PSC cell line decreased proliferation and senescence and SR/TGF-β1/VEGF-A axis but increased the expression of miR-125b and FoxA2. Down-regulation of FoxA2 prevented SCT 5-27-induced reduction in biliary damage, whereas overexpression of FoxA2 reduced proliferation and senescence in the human PSC cell line.
Conclusions:
Modulating the SCT/SR axis may be critical for managing PSC.
Herbal medicinal products are widely considered beneficial and gaining importance in preventing and treating several diseases. Urtica dioica L. (UD) is a medicinal plant that has been used as an herbal remedy and dietary supplement for centuries based on traditional experience or random trials without the know-how of phytoconstituents. UD is one of those herbs with a long record of anti-inflammatory activity and several mechanisms of action have been discussed. Plant part, extraction solvent, and phytoconstituents have a determinant effect on both efficacy and therapeutic objective. Current literature mainly elaborates on the antioxidant effect of Urtica species, with the anti-inflammatory role of UD still being a matter of discussion, as in vitro and in vivo studies have only been characterized to such an extent. In order to elaborate on this topic, the present review aims to characterize the anti-inflammatory action of several UD extracts according to in vitro and in vivo results, as well as the possible molecules and respective mechanism responsible for its anti-inflammatory effect on several pathologies. Despite the knowledge gathered so far surrounding the anti-inflammatory activity of UD, further studies are required to characterize the mechanism of action and discriminate between the molecules underlying the beneficial effects of nettle on inflammatory diseases.
Autism spectrum disorder (ASD) is a neurodevelopmental illness characterized by impaired social interaction and restricted repetitive behaviors or interests. The rising prevalence of ASD diagnosis has triggered a surge in research into investigating the underlying neuropathological processes and finding new therapeutic approaches. ASD is characterized by neuroinflammation and dysregulation of neuro-immune cross-talk, which suggests that stem cell treatment might be a potential therapeutic approach. The beneficial and restorative effects of stem cells are mainly due to their paracrine activity, in which stem cells generate and release extracellular vesicles such as exosomes and distinct secreted non-vesicle soluble proteins, including, growth factors, chemokines, cytokines, and immunomodulatory molecules referred to as the Secretome. In this paper, we reviewed the existing research exploring the therapeutic potential of stem cell secretome focusing on their role in addressing ASD pathology. Furthermore, we proposed a comprehensive mechanism of action for stem cell secretions, encompassing the broader secretome as well as the specific contribution of exosomes, in alleviating ASD neuropathology. Across the reviewed studies, exosomes and secreted soluble factors of the transplanted stem cell demonstrate a potential efficacy in ameliorating autistic-like behaviors. The proposed mechanism of action involves the modulation of signaling pathways implicated in neuroinflammation, angiogenesis, cellular apoptosis, and immunomodulation.
Graphical Abstract
Fine dust concentrations come in direct contact with the human respiratory system, thereby reducing lung function and causing respiratory diseases such as asthma and rhinitis. The aim of this study was to evaluate the efficacy of GHX02 (combination of four herbs [Trichosanthes kirilowii, Prunus armeniaca, Coptis japonica, and Scutellaria baicalensis]), a herbal extract with established efficacy against bronchitis and pulmonary disease, in the treatment of asthma accompanied by rhinitis aggravated by fine dust. Therefore, we constructed an asthma-rhinitis mouse model of Balb/c mice challenged with ovalbumin (OVA) and fine diesel particulate matter, which were administered with three concentrations of GHX02. GHX02 significantly inhibited the increase of total cells and immune cells in bronchoalveolar lavage fluid, lung tissue, and nasal ductal lymphoid tissue (NALT). GHX02 also reduced the severity of histological lung injury and the expression of interleukin (IL)-1α and nuclear factor kappa B (NF-κB), which regulate inflammatory responses. The results indicate that GHX02 inhibited the inflammatory immune response in mice. Therefore, this study highlights the potential of GHX02 as a treatment for patients with asthma accompanied by rhinitis. Balb/c mice were challenged with OVA and PM10D, and then treated with three concentration of GHX02. GHX02 significantly inhibited the increase of total cells, immune cells lymphocytes, neutrophils, and macrophages, as well as their expression in lung tissue. GHX02 significantly inhibited the increase of total cells and immune cells in NALT. GHX02 decreased the severity of histological lung injury, expression of IL-1α and NF-κB. This study suggests the probability that GHX02 is effective for asthma patients with rhinitis by inhibiting inflammatory immune response.
Tumor-associated macrophages (TAMs) are the major component of the tumor microenvironment (TME), where they sustain tumor progression and or-tumor immunity. Due to their plasticity, macrophages can exhibit anti- or pro-tumor functions through the expression of different gene sets leading to distinct macrophage phenotypes: M1-like or pro-inflammatory and M2-like or anti-inflammatory. NF-κB transcription factors are central regulators of TAMs in cancers, where they often drive macrophage polarization toward an M2-like phenotype. Therefore, the NF-κB pathway is an attractive therapeutic target for cancer immunotherapy in a wide range of human tumors. Hence, targeting NF-κB pathway in the myeloid compartment is a potential clinical strategy to overcome microenvironment-induced immunosuppression and increase anti-tumor immunity. In this review, we discuss the role of NF-κB as a key driver of macrophage functions in tumors as well as the principal strategies to overcome tumor immunosuppression by targeting the NF-κB pathway.
Background & Aims: Maintenance of hepatocyte homeostasis plays an important role in mediating the pathogenesis of many diseases. A growing body of literature has established a critical role played by TNFα in maintaining hepatocyte homeostasis; however, the transcriptional mechanisms underlying constitutive Tnf expression is unknown. Methods: Whole liver fractions and primary hepatocytes from adult control C57BL/6 mice and the murine hepatocyte cell line, AML12, was assessed for constitutive Tnf expression. Impacts of GSK3β and NF-κB inhibition on constitutive Tnf expression was assessed in AML12 cells. Finally, AML12 cell proliferation following GSK3β and NF-κB inhibition was evaluated. Results: Constitutive Tnf gene expression is present in whole liver, primary hepatocytes and cultured AML12 hepatocytes. Cytokine induced Tnf gene expression is regulated by NF-κB activation. Pharmacologic inhibition of GSK3β resulted in a time- and dose-dependent inhibition of Tnf gene expression. GSK3β inhibition decreased nuclear levels of the NF-κB subunits p65 and p50. We determined that NF-κB transcription factor subunit p65 binds to consensus sequence elements present in the murine TNFα promoter and inhibition of GSK3β decreases binding and subsequent Tnf expression. Finally, AML12 cell growth was significantly reduced following GSK3β and NF-κB inhibition. Conclusion: These results demonstrate that GSK3β and NF-κB are essential for mediating Tnf expression and constitutive hepatocyte cell growth. These findings add to a growing body of literature on TNFα mediated hepatocyte homeostasis and identify novel molecular mechanisms involved in mediating response to various disease states in the liver.
The loss of skeletal muscle, also known as sarcopenia, is an aging-associated muscle disorder that is disproportionately present in heart failure (HF) patients. HF patients with sarcopenia have poor outcomes compared to the overall HF patient population. The prevalence of sarcopenia in HF is only expected to grow as the global population ages, and novel treatment strategies are needed to improve outcomes in this cohort. Multiple mechanistic pathways have emerged that may explain the increased prevalence of sarcopenia in the HF population, and a better understanding of these pathways may lead to the development of therapies to prevent muscle loss. This review article aims to explore the molecular mechanisms linking sarcopenia and HF, and to discuss treatment strategies aimed at addressing such molecular signals.
Inflammatory response is one of the essential parts of various pathogenic mechanisms of radiation-induced salivary dysfunction. The effect of decreasing the levels of inflammatory cytokines on alleviating submandibular gland injuries after irradiation is unclear. This study aimed to explore the effect of the antibody against tumor necrosis factor-alpha, infliximab, on radiation-induced submandibular gland dysfunction in rats. Male Wistar rats received a single 20 Gy dose to the right submandibular gland region or sham irradiated. Meanwhile, the irradiated group was divided into infliximab treatment groups or untreated groups. Animals were euthanized at 1, 6, and 12 weeks postirradiation, and the irradiated submandibular gland was dissected for subsequent detection. Submandibular gland exposure caused obvious pathological changes. The increased levels of inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1β, and interleukin-6, represent an aggravated inflammatory response. The results of the western blot, reverse transcription-quantitative polymerase chain reaction, and immunofluorescence staining showed upregulated levels of claudin-1, claudin-3, and aquaporin 5 and downregulated levels of claudin-4. Moreover, nuclear factor kappa-B phosphorylation levels were also up-regulated. In subsequent experiments, we found that infliximab alleviated inflammatory response, up-regulated tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 levels, and improved claudin-1, claudin-3, claudin-4, and aquaporin 5 expression. Our results indicate that infliximab might improve the para-cellular pathway and trans-cellular pathway destruction by reducing the inflammatory.
Diabetes mellitus is a complex metabolic syndrome that involves dysfunction of spleen and other lymphoid organs. Medicinal plants, including okra (Abelmoschus esculentus (L.) Moench), were used widely for diabetes treatment. Scarce data are available about the potential anti-diabetic effects of okra, the histopathological alterations in splenic tissues and the mechanistic pathways underlying this association. The current research investigated the effects of okra pod extract on the biochemical parameters and expression of CD8⁺ T cells and nuclear factor kappa (NF-k) B and releasing proinflammatory cytokines in spleen in streptozotocin (STZ)-induced diabetic rat models. A total of 50 mature male Wister albino rats were divided into five isolated groups; the first served as control (untreated) animals, the second (DM group) diabetes induced by STZ (at a dose of 45 mg/kg body weight, administered intraperitoneally), the third group (DM + Insulin): diabetic rats administered insulin subcutaneously (10 units/kg bw/day) daily for 4 weeks, the fourth group was administrated 400 mg/kg okra extract daily for 4 weeks, and diabetic induced rats in the fifth group were administrated 400 mg/kg okra extract daily for 4 weeks. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity in Abelmoschus esculentus (L.) Moench was studied, and the content of phenolic compounds in okra pods was estimated using high-performance liquid chromatography. Diabetes induction led to decreased body weight, increased blood glucose levels. Capsular thickness was significantly increased, white pulp was widely dispersed, and mature lymphocytes in the periphery were also drastically decreased, with thick follicular arteries, necrosis, and depletion of lymphocytes in the germinal center. Red pulp revealed severe congestion and degenerative changes, deposition of hemosiderin granules and lymphocytic depletion. In addition, collagen fiber deposition was increased also in this group. The induction of diabetes exaggerated NF-kβ expression and mediated downregulation of the expression of CD8⁺ T cells in spleen tissue. Interestingly, oral administration of okra extracts post diabetes induction could mitigate and reverse such adverse effects. Altogether, our study points out the potential benefits of okra in improving blood glucose levels and restoring histopathological alterations in splenic tissues through CD8⁺ T cells and NF-kβ expression in a diabetic rat model.
Nitro-conjugated linoleic acid (NO2-CLA) has been observed to manifest salutary signaling responses, including anti-inflammatory and antioxidant properties. Here, the authors have explored the influence and underlying mechanisms of NO2-CLA on the proinflammatory reaction of murine macrophages that were challenged with lipopolysaccharide (LPS) derived from Prevotella intermedia, a putative periodontopathic bacterium. Treatment of LPS-activated RAW264.7 cells with NO2-CLA notably dampened the secretion of iNOS-derived NO, IL-1β and IL-6 as well as their gene expressions and significantly enhanced the markers for M2 macrophage polarization. NO2-CLA promoted the HO-1 expression in cells challenged with LPS, and tin protoporphyrin IX, an HO-1 inhibitor, significantly reversed the NO2-CLA-mediated attenuation of NO secretion, but not IL-1β or IL-6. We found that cells treated with NO2-CLA significantly increased mRNA expression of PPAR-γ compared to control cells, and NO2-CLA significantly reverted the decrease in PPAR-γ mRNA caused by LPS. Nonetheless, antagonists to PPAR-γ were unable to reverse the NO2-CLA-mediated suppression of inflammatory mediators. In addition, NO2-CLA did not alter the p38 and JNK activation elicited by LPS. Both NF-κB reporter activity and IκB-α degradation caused by LPS were notably diminished by NO2-CLA. NO2-CLA was observed to interrupt the nuclear translocation and DNA binding of p50 subunits caused by LPS with no obvious alterations in p65 subunits. Further, NO2-CLA attenuated the phosphorylation of STAT1/3 elicited in response to LPS. We propose that NO2-CLA could be considered as a possible strategy for the therapy of periodontal disease, although additional researches are certainly required to confirm this.
Background:
Adult T-cell leukemia/lymphoma (ATL) is a lymphoid malignancy caused by HTLV-1 infection, with distinct geographical distribution. Despite advances in cancer treatment, the average survival rate of ATL is low. Conferone is a natural coumarin extracted from Ferula species with a wide range of pharmaceutical effects. In search for a novel chemotherapeutic agent, we investigated the cytotoxicity of conferone on ATL cells.
Methods:
To obtain conferone, the methanolic extract of the roots of F. flabelliloba was subjected to silica gel column chromatography, followed by 1H- and 13C-NMR to confirm its structure. For cytotoxicity assay, MT-2 cells were treated with different concentrations of conferone (2.5, 5, 10, 20, and 40 µM) for 24, 48, and 72 h, and viability was evaluated by a colorimetric assay using alamarBlue. Cell cycle was analyzed by PI staining and flow cytometry, and qPCR was used to study the expression of candidate genes.
Results and conclusion:
Obtained findings indicated that conferone induced considerable cytotoxic effects on MT-2 cells in a time- and dose-dependent manner. In addition, accumulation of cells in the sub-G1 phase of the cell cycle was detected upon conferone administration. Moreover, conferone reduced the expression of CDK6, c-MYC, CFLIPL, and NF-κB (Rel-A) in MT-2 cells. Accordingly, conferone could be considered as a potent agent against ATL, although complementary investigations are required to define more precisely its mechanism of action.
Global deoxygenation in aquatic systems is an increasing environmental problem, and substantial oxygen loss has been reported. Aquatic animals have been continuously exposed to hypoxic environments, so-called "dead zones," in which severe die-offs among organisms are driven by low-oxygen events. Multiple studies of hypoxia exposure have focused on in vivo endpoints, metabolism, oxidative stress, and immune responses in aquatic invertebrates such as molluscs, crustaceans, echinoderms, and cnidarians. They have shown that acute and chronic exposure to hypoxia induces significant decreases in locomotion, respiration, feeding, growth, and reproduction rates. Also, several studies have examined the molecular responses of aquatic invertebrates, such as anaerobic metabolism, reactive oxygen species induction, increased antioxidant enzymes, immune response mechanisms, regulation of hypoxia-inducible factor 1-alpha (HIF-1α) genes, and differently expressed hemoglobin/hemocyanin. The genetic basis of those molecular responses involves HIF-1α pathway genes, which are highly expressed in hypoxic conditions. However, the identification of HIF-1α-related genes and understanding of their applications in some aquatic invertebrates remain inadequate. Also, some species of crustaceans, rotifers, sponges, and ctenophores that lack HIF-1α are thought to have alternative defense mechanisms to cope with hypoxia, but those factors are still unclear. This review covers the formation of hypoxia in aquatic environments and the various adverse effects of hypoxia on aquatic invertebrates. The limitations of current hypoxia research and genetic information about the HIF-1α pathway are also discussed. Finally, this paper explains the underlying processes of the hypoxia response and presents an integrated program for research about the molecular mechanisms of hypoxic stresses in aquatic invertebrates.
Blood Oxidant Ties: The Evolving Concepts in Myocardial Injury and Cardiovascular Disease is an update on the recent advances in the development of antioxidant-based therapies. It starts with an overview of the mechanisms underlying the genesis of oxidative stress, summarizing the link between oxidative stress and a number of cardiovascular conditions. This is followed by an explanation of how oxidative stress interacts with lipid metabolism and the placental environment. Three chapters on the role of antioxidant-based therapy for cardiovascular diseases round up the book.
Key Features
- Outlines several cell-signaling pathways that are modulated by the interplay between reducing and oxidizing agents (redox status) and gene expression in the cardiovascular disease process
- Brings information about maternal programming environment in the placenta
- Covers development of novel nanotechnology-based antioxidant delivery systems for effective drug delivery
- Includes references for further reading
The book is aimed at a broad readership of scientific and medical professionals involved in research on cardiovascular diseases, pathophysiology, pharmacy, pharmaceutical science and life sciences. It also serves as a reference for scholars who want to understand the complex biochemical mechanisms of antioxidant agents.
Pattern recognition receptors (PRR) are genetically encoded proteins which recognize a host of highly conserved “danger signals” produced by microbial organisms (pathogen-associated molecular patterns, or PAMPs) or released by damaged host cells (damage-associated molecular patterns, or DAMPs). PAMP or DAMP-mediated activation of PRR-bearing immune cells is a critical step in initiating an immune response. The Toll-like receptors (TLRs) are a small family of proteins with deep evolutionary origins; they are present in both invertebrate and vertebrate species and all TLR members share a common Toll-Interleukin-1 Receptor (TIR) domain. There is considerable variation in the number of TLRs present in different species with Drosophila (9), mice (12), and humans (10) each having a slightly different number which pales in comparison to the number present in purple sea urchins (222). In this chapter, we discuss the basic biology of the TLRs, including their activation, subcellular localization, and downstream signaling. We highlight the critical role that TLRs play in initiating innate and adaptive immune responses and emphasize a discussion of how TLR-mediated proinflammatory signaling is coupled to pain or itch through neuro–immune interactions. We also highlight emerging evidence that suggests TLR signaling in sensory neurons can rapidly modulate neuronal excitability and discuss the physiological consequences of non-canonical TLR signaling in neurons. Overall, this chapter reviews the plethora of evidence which now exists to support the many ways in which TLR signaling can regulate sensory function via neuro–immune interactions.KeywordsToll-like receptor (TLR)TLR4TLR5TollPattern recognition receptor (PRR)Pathogen-associated molecular pattern (PAMP)Damage-associated molecular pattern (DAMP)ImmunityNociception
Today, treatment options for cancer patients typically include surgery, radiation therapy, immunotherapy, and chemotherapy. While these therapies have saved lives and reduced pain and suffering, cancer still takes millions of lives every year around the world. Researchers are now developing advanced therapeutic strategies such as immunotherapy, targeted therapy, and combination nanotechnology for drug delivery. In addition, the identification of new biomarkers will potentiate early-stage diagnosis. Molecular Targets and Cancer presents information about cancer diagnosis and therapy in a simple way. It covers several aspects of the topic with updated information on par with medical board levels. The book features contributions from experts and includes an overview of cancer from basic biology and pathology, classifications, surveillance, prevention, diagnosis, types of cancer, treatment and prognosis. The first part of this book introduces the reader to cancer epidemiology, genetic alterations in cancer, exogenous and endogenous factors in carcinogenesis, roles for growth factors in cancer progression, cell signaling in cancer, transcription factors in cancer, and cancer genetics and epigenetics. This comprehensive guide is a valuable resource for oncologists, researchers, and all medical professionals who work in cancer care and research.
Background and Aims: Olfactomedin-4 is a glycoprotein that is upregulated in inflamed gastrointestinal tissues. This study aimed to investigate the role and underlying mechanisms of olfactomedin-4 in ulcerative colitis.
Methods: C57BL/6 mice and olfactomedin-4 knockout mice were fed dextran sulfate sodium in drinking water to establish a colitis model. An in vitro inflammation model was constructed in HCT116 and NCM460 cells stimulated with lipopolysaccharide. The expression of olfactomedin-4 was detected by Western blotting, immunohistochemistry staining, and qRT‒PCR. The differences in the severity of colitis between olfactomedin-4 knockout mice and wild-type mice were compared, and the underlying mechanisms were explored.
Results: Olfactomedin-4 expression was significantly upregulated in colonic tissues of active ulcerative colitis patients and in cellular and mouse models of colitis. Compared with wild-type littermates, olfactomedin-4 knockout mice were more susceptible to dextran sulfate sodium-induced colitis and produced higher levels of proinflammatory cytokines and chemokines. In addition, olfactomedin-4 deficiency significantly promoted intestinal epithelial cell apoptosis and increased intestinal permeability, which was mediated by the p53 pathway. Moreover, olfactomedin-4 directly interacted with and negatively regulated matrix metalloproteinase-9. Inhibiting matrix metalloproteinase-9 significantly decreased colonic p53 expression and ameliorated experimental colitis in olfactomedin-4 knockout mice, while overexpression of matrix metalloproteinase-9 aggravated colitis. Further experiments showed that matrix metalloproteinase-9 regulated p53 through the Notch1 signaling pathway to promote ulcerative colitis progression.
Conclusions: Olfactomedin-4 is significantly upregulated in ulcerative colitis and may protect against colitis by directly inhibiting matrix metalloproteinase-9 and further decreasing p53-mediated apoptosis via Notch1 signaling.
In view of its heterogeneity, schizophrenia needs new diagnostic tools based on mechanistic biomarkers that would allow early detection. Complex interaction between genetic and environmental risk factors may lead to NMDAR hypofunction, inflammation and redox dysregulation, all converging on oxidative stress. Using computational analysis, the expression of 76 genes linked to these systems, known to be abnormally regulated in schizophrenia, was studied in skin-fibroblasts from early psychosis patients and age-matched controls (N = 30), under additional pro-oxidant challenge to mimic environmental stress. To evaluate the contribution of a genetic risk related to redox dysregulation, we investigated the GAG trinucleotide polymorphism in the key glutathione (GSH) synthesizing enzyme, glutamate-cysteine-ligase-catalytic-subunit (gclc) gene, known to be associated with the disease. Patients and controls showed different gene expression profiles that were modulated by GAG-gclc genotypes in combination with oxidative challenge. In GAG-gclc low-risk genotype patients, a global gene expression dysregulation was observed, especially in the antioxidant system, potentially induced by other risks. Both controls and patients with GAG-gclc high-risk genotype (gclcGAG-HR) showed similar gene expression profiles. However, under oxidative challenge, a boosting of other antioxidant defense, including the master regulator Nrf2 and TRX systems was observed only in gclcGAG-HR controls, suggesting a protective compensation against the genetic GSH dysregulation. Moreover, RAGE (redox/inflammation interaction) and AGMAT (arginine pathway) were increased in the gclcGAG-HR patients, suggesting some additional risk factors interacting with this genotype. Finally, the use of a machine-learning approach allowed discriminating patients and controls with an accuracy up to 100%, paving the way towards early detection of schizophrenia.
Background
Colony-stimulating factor 3 (CSF3) is a cytokine associated with inflammation, which mainly stimulates myeloid stem cell maturation, proliferation, and migration into circulation. However, the significance of CSF3 in colorectal cancer (CRC) remains unclear. Here, we aimed to examine the expression and impacts of CSF3 in CRC.
Methods
CSF3 expression was examined in CRC tissues and cells by IHC staining and western blot. RNA interference was used to silence CSF3 in CRC cells. The effects of CSF3 on biological behaviors such as proliferation and migration of CRC cells were examined in vitro and in vivo.
Results
CSF3 was highly expressed in CRC tissues and cells. CSF3 high level was correlated to patients’ age, with a feature of a higher pathological stage, more distant lymphatic metastasis and more severe lymph node invasion. Knocking down CSF3 led to decreased proliferation and migration, increased apoptosis, arrested cell cycle in vitro as well as impaired tumor growth in vivo. Mechanistically, CSF3 regulates CRC cell proliferation and apoptosis dependent on enhances p65 phosphorylation to facilitate NF-κB-mediated transcriptional activity.
Conclusion
Our study demonstrated that CSF3 interacts with the NF-κB signaling pathway to promote the progression of CRC. CSF3 might be a potential therapeutic target for CRC patients.
Curcumin is less bioavailable and therefore gets rapidly eliminated from the body. Structural modification of curcumin and its complexation with excipients like 2-Hydroxypropyl-β-cyclodextrin (HPβCD) can circumvent such limitations in respective manners. This study expects to enhance curcumin’s bioactivity by amalgamating both the techniques. Curcumin had been structurally modified and then complexed with HPβCD, characterized, and evaluated for different bioactivities. This manuscript demonstrates that the death of cancer cells followed the apoptotic pathway as estimated from the apoptosis assay. Further, the prepared samples acted as a potent antibacterial and antifungal agents against several bacteria and a fungus, respectively. The samples have more polyphenolic and flavonoid contents compared to curcumin and thereby exhibited better antioxidant activities as estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) & 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. The samples also exhibited better metal chelation activities. All the samples, especially CPCD, prevented the impairment of insulin-stimulated 2-NBDG uptake by L6 myotubes. The samples reduced the LPS-induced κB luciferase reporter activity. Despite having so many properties, the samples were found to be non-toxic to human PBMCs and RBCs. Curcumin pyrazole-HPβCD inclusion complex is found to be more water soluble compared to either curcumin or curcumin pyrazole and hence has better anticancer, antioxidant, antibacterial, antifungal, antidiabetic & anti-inflammatory activities without being toxic to human PBMCs and RBCs as examined by different in vitro assays.
Dithiocarbamates and iron chelators were recently considered for the treatment of AIDS and neurodegenerative diseases. In this study, we show that dithiocarbamates and metal chelators can potently block the activation of nuclear factor kappa B (NF-kappa B), a transcription factor involved in human immunodeficiency virus type 1 (HIV-1) expression, signaling, and immediate early gene activation during inflammatory processes. Using cell cultures, the pyrrolidine derivative of dithiocarbamate (PDTC) was investigated in detail. Micromolar amounts of PDTC reversibly suppressed the release of the inhibitory subunit I kappa B from the latent cytoplasmic form of NF-kappa B in cells treated with phorbol ester, interleukin 1, and tumor necrosis factor alpha. Other DNA binding activities and the induction of AP-1 by phorbol ester were not affected. The antioxidant PDTC also blocked the activation of NF-kappa B by bacterial lipopolysaccharide (LPS), suggesting a role of oxygen radicals in the intracellular signaling of LPS. This idea was supported by demonstrating that treatment of pre-B and B cells with LPS induced the production of O2- and H2O2. PDTC prevented specifically the kappa B-dependent transactivation of reporter genes under the control of the HIV-1 long terminal repeat and simian virus 40 enhancer. The results from this study lend further support to the idea that oxygen radicals play an important role in the activation of NF-kappa B and HIV-1.
The bcl-3 gene product, overexpressed in chronic lymphocytic leukemia (CLL) patients with the translocation t(14;19), is a member of the I kappa B family. The bcl-3 protein is able to inhibit the DNA binding and trans-activation of authentic NF-kappa B heterodimers p50-p65 and p49-p65, as well as p50 and p49 homodimers. The bcl-3 protein does not inhibit either the DNA-binding activity of the Rel protein or its ability to trans-activate genes linked to the kappa B site. A human 37-kD protein (I kappa B alpha), identified previously as a member of the I kappa B family, is also unable to inhibit DNA-binding activity of the Rel protein. However, unlike bcl-3, the 37-kD (I kappa B alpha) protein has no effect on the DNA-binding activity of p50 or p49 homodimers. Two dimensional phosphotryptic peptide maps of the human bcl-3 and the human 37-kD (I kappa B alpha) proteins reveal that the phosphopeptides from the 37-kD (I kappa B alpha) protein are nested within the bcl-3 protein. Furthermore, bcl-3 antisera immunoprecipitates an in vitro-radiolabeled 37-kD (I kappa B alpha) protein. Proteins of 56 and 38 kD can be identified in HeLa cells stimulated with PMA and immunoprecipitated with bcl-3 antisera. Comparison of tryptic peptide maps of the bcl-3 protein synthesized in vitro, and p56 and p38 from HeLa cells, shows that they are all structurally related. Removal of the amino-terminal sequences of the bcl-3 protein generates a protein that inhibits the DNA binding of the p50-p65 heterodimer but, like the 37-kD (I kappa B alpha) protein, is no longer able to inhibit the binding of the p50 and p49 homodimers with kappa B DNA. We propose that the bcl-3 and 37-kD (I kappa B alpha) proteins are related and are members of the I kappa B family.
A role for redox regulation In activation of the NF-xB transcription factor was suggested by the observation that DNA binding
activity of free protein, but not preformed DNA-proteln complex , is inhibited by -SH modifying agents but enhanced by reducing
agents. Mutagenesis of conserved cysteine residues in the p50 subunit identified amino acid 62 as being important for DNA
binding, as a serine substitution at this position reduces DNA binding affinity, but renders the protein Insensitive to -SH
modifying agents. DNA binding activity of the wild type protein but not the amino acid 62 mutant was also stimulated by thioredoxin
while detection of disulphide cross linked dlmers in p50 but not the amino acid 62 mutant suggests that thioredoxin stimulates
DNA binding by reduction of a disulphide bond involving cysteine 62. The physiological relevance of these findings was supported
by the observation that cotransfection of a plasmid expressing human thioredoxin and an HIV LTR driven reporter construct
resulted in an NF-xB dependent increase in expression of the reporter gene. Thus modification of p50 by thioredoxin, a gene
induced by stimulation of T-lymphocytes in parallel with NF-xB translocation, is a likely step in the cascade of events leading
to full NF-xB activation.
The inducible pleiotropic transcription factor NF-kappa B is composed of two subunits, p50 and p65. The p50 subunit is encoded on the N-terminal half of a 105-kDa open reading frame and contains a rel-like domain. To date, no function has been described for the C-terminal portion. We show here that the C-terminal half of p105, when expressed as a separate molecule, binds to p50 and can rapidly disrupt protein-DNA complexes of p50 or native NF-kappa B. Deletion analysis of this precursor-derived inhibitor activity indicated a domain containing ankyrin-like repeats as necessary for inhibition. The protooncogene bcl-3, which contains seven ankyrin repeats, can equally inhibit p50 DNA binding. These observations identify bcl-3 as an inhibitor of NF-kappa B and strongly suggest that the ankyrin repeats in these factors are involved in protein-protein interactions with the rel-like domain of p50. Comparison with other ankyrin repeat-containing proteins suggests that a subclass of these proteins acts as regulators of rel-like transcription factors.
To understand the mechanism by which pp40/I kappa B beta inhibits DNA binding activity of the rel/NF-kappa B family of transcription factors, we have investigated the role of ankyrin repeats on the biological function of pp40 by deleting or mutating conserved residues. We show that (i) ankyrin repeats alone are not sufficient to manifest biological activity but require the C-terminal region of the pp40 protein; (ii) four out of the five ankyrin repeats are essential for inhibiting the DNA binding activity; (iii) pp40 mutants that do not inhibit DNA binding of rel protein also do not associate with rel; (iv) although pp40 can associate with the p65 and p50 subunits of NF-kappa B, pp40 inhibits the DNA binding activity of only the p50-p65 heterodimer and the p65 homodimer; and (v) pp40 inhibits the transcription of genes linked to kappa B site; however, mutants that do not affect DNA binding have no effect. We propose that the ankyrin repeats and the C-terminal region of pp40 form a structure that associates with the rel homology domain to inhibit DNA binding activity.
The NF-kappa B transcription factor complex is comprised of two subunits, p50 and p65, that share significant homology to the rel oncogene. We have isolated a cDNA encoding a novel 66-kD rel-related protein, designated I-Rel. Unlike other rel-related proteins, I-Rel does not interact with DNA. I-Rel forms heterodimers with p50, however, and greatly attenuates its DNA-binding activity--an effect probably resulting from the presence of a domain inhibitory to DNA binding present within the 121 amino-terminal residues of I-Rel. In contrast, I-Rel does not associate with p65. Transfection experiments demonstrate that I-Rel suppresses NF-kappa B-induced transcription, probably through its association with p50. Expression of I-Rel mRNA is induced by mitogenic stimulation and accumulates after the appearance of p50 transcripts. Our findings suggest that p50 and I-Rel are components of a feedback pathway where expression of I-Rel may modulate indirectly the expression of genes responsive to the NF-kappa B transcription factor complex.
The NF-kappa B subunits, p50 and p65, have extensive sequence homology with the c-rel proto-oncogene and the Drosophila morphogen dorsal. It has recently been shown that in vitro translated c-Rel can bind to DNA and form a complex with p50. However, the conditions for DNA binding of c-Rel in vivo and its DNA sequence specificity have not been established. Here we report the identification a novel heterodimeric complex that binds to a kappa B-like, phorbol ester (TPA) responsive DNA sequence, 5'-GGGAAAGTAC-3', in the 5' flanking region of the human urokinase (uPA) gene. This sequence was shown to bind two protein complexes, LC and UC. LC was indistinguishable from NF-kappa B as it reacted with antibodies recognizing the p50 subunit of NF-kappa B, and was shown by UV crosslinking to contain the p50 and p65 subunits of NF-kappa B. UC, on the other hand, strongly reacted with anti-v-Rel, but not with the anti-p50 antibodies, and was shown by crosslinking to contain 75 kDa and 85 kDa protein-DNA adducts. The 75 kDa and the 85 kDa adducts could be immunoprecipitated only by anti-p65 and anti-c-Rel antibodies, respectively, showing that c-Rel formed a heterodimer with p65. Both protein complexes were present in inactive forms in HeLa cell cytosol, and their nuclear translocation was induced by TPA. DNA binding of UC and LC could, furthermore, be inhibited by I kappa B-alpha.(ABSTRACT TRUNCATED AT 250 WORDS)
The transcription factor NF-kappa B is a protein complex which comprises a DNA-binding subunit and an associated transactivation protein (of relative molecular masses 50,000 (50K) and 65K, respectively). Both the 50K and 65K subunits have similarity with the rel oncogene and the Drosophila maternal effect gene dorsal. The 50K DNA-binding subunit was previously thought to be a unique protein, derived from the 105K gene product (p105). We now report the isolation of a complementary DNA that encodes an alternative DNA-binding subunit of NF-kappa B. It is more similar to p105 NF-kappa B than other family members and defines a new subset of rel-related genes. It is synthesized as approximately 100K protein (p100) that is expressed in different cell types, contains cell cycle motifs and, like p105, must be processed to generate a 50K form. A 49K product (p49) can be generated independently from an alternatively spliced transcript; it has specific kappa B DNA-binding activity and can form heterodimers with other rel proteins. In contrast to the approximately 50K protein derived from p105, p49 acts in synergy with p65 to stimulate the human immunodeficiency virus (HIV) enhancer in transiently transfected Jurkat cells. p49/p100 NF-kappa B could therefore be important in the regulation of HIV and other kappa B-containing genes.
NF-kappa B is a widely used regulator of inducible and tissue-specific gene control. In the cytosol, when complexed to an inhibitory molecule, I kappa B, NF-kappa B is in an inactive form and cannot bind DNA. Activation of cells with appropriate stimuli results in the dissociation of NF-kappa B from I kappa B and its translocation to the nucleus as an active binding protein. We now demonstrate that NF-kappa B binding in vitro can be inhibited by agents that modify free sulfhydryls. Binding is eliminated after treatment with N-ethylmaleimide, an alkylating agent, and diamide, an oxidizing agent. The diamide effect can be reversed by 2-mercaptoethanol. Further, 2-mercaptoethanol acts synergistically with deoxycholate plus Nonidet P-40 in converting inactive cytosolic NF-kappa B to an active DNA-binding form. It is therefore possible that modulation of the redox state of NF-kappa B could represent a post-translational control mechanism for this factor.
AMYOTROPHIC lateral sclerosis (ALS) is a degenerative disorder of motor neurons in the cortex, brainstem and spinal cord1,2. Its cause is unknown and it is uniformly fatal, typically within five years3. About 10% of cases are inherited as an autosomal dominant trait, with high penetrance after the sixth decade4,5. In most instances, sporadic and autosomal dominant familial ALS (FALS) are clinically similar4,6,7. We have previously shown that in some but not all FALS pedigrees the disease is linked to a genetic defect on chromosome 21q (refs 8, 9). Here we report tight genetic linkage between FALS and a gene that encodes a cytosolic, Cu/Zn-binding superoxide dismutase (SOD1), a homodimeric metalloenzyme that catalyzes the dismutation of the toxic superoxide anion O2.- to O2 and H2O2 (ref. 10). Given this linkage and the potential role of free radical toxicity in other neurodenegerative disorders11, we investigated SOD1 as a candidate gene in FALS. We identified 11 different SOD1 missense mutations in 13 different FALS families.
We have explored the cis-acting elements necessary for the LPS-mediated activation of the mouse TNF-alpha promoter by transfecting a set of 5' deletion mutants linked to the CAT reporter gene into primary bone marrow-derived macrophages. A major drop in inducibility by LPS was seen upon deletion of a region mapping between nt -655 and nt -451. Gel retardation assays revealed that LPS induced the appearance in this region of several specific DNA-protein complexes mapping to sequence motifs with strong homology to the kappa B enhancer. Constructs containing two or more copies of one of the kappa B enhancer motifs linked to a heterologous promoter were inducible by LPS. Additional deletion of a region between nt -301 and nt -241, which contains a MHC class II-like "Y box" and formed a Y box-specific complex with a protein whose concentration was increased by LPS, caused a nearly complete loss of inducibility by LPS. We speculate that NF-kappa B and/or related proteins are involved in the LPS-induced transcriptional activation of the TNF-alpha gene, and that factors interacting with the Y box can additionally modulate the activity of the gene in macrophages.
The p50 subunit of the NF-χB transcription complex is derived from the N-terminal half of a larger precursor protein, p105.
Although a fair amount is known about functions located within the p50 sequences, less is known about the C-terminal half
of p105. In this report, we have identified a potent transcription activation domain located in the C terminus of mouse p105.
In addition, the IχBβ proteins chicken p40 and human MAD-3, proteins that are related to the p105 C terminus, strongly activated
transcription in chicken cells and yeast when fused to GAL4 DNA-binding sequences. Furthermore, chicken p40 is primarily located
in the nucleus of chicken cells when overexpressed from a retroviral vector. Our results suggest novel models for the function
and regulation of NF-χB transcription complexes.
The C-terminal half of the p105 precursor of the NF-κB p50 subunit contains ankyrin-like repeats similar to those in IκB molecules, which are known to retain NF-κB complexes in the cytoplasm. We demonstrate that in various cell lines p105 is found associated with either c-rel or p65 in the cytoplasm and serves IκB-like functions. p105 retains c-rel or p65 in the cytoplasm in cotransfection experiments in COS cells. It also inhibits DNA binding by c-rel in gel retardation assays. Stable interaction of p105 with c-rel or p65 requires the putative dimerization domain in the conserved rel homology region of p105, as well as a second contact with the IκB-related C-terminal part of p105. Pulse-chase experiments indicate that cytoplasmic complexes of p105 with c-rel or p65 give rise to cytoplasmic as well as nuclear p50-c-rel and p50–p65, respectively, probably through processing of p105. Thus, p105, like the IκBs, controls the subcellular localization and hence the transcriptional activity of at least two other members of the rel/NF-κB family.
The maternal determinants of dorsoventral polarity of the Drosophila embryo are derived from somatic and germ-line components of the egg chamber. During oogenesis, asymmetry seems to be established by a signal transduction process. This process is thought to provide the developing embryo with a ventral signal responsible for determining the embryonic axis. Through a set of interactions that may involve signal transduction and proteolytic cascade events, positional information is generated in the form of a graded distribution of dorsal protein in blastoderm nuclei. Different levels of dorsal protein result in asymmetric expression of zygotic genes that ultimately specify cell fate.
The production of TNF/cachectin by human B cell lines and tonsillar B cells was examined. Of the 15 B cell lines examined, 9 cell lines synthesize TNF mRNA constitutively. PMA stimulated most cell lines to accumulate increased amounts of TNF. SeD, 8866P, 32al, RPMI 1788, and four bone marrow-derived EBV-transformed cell lines accumulated high levels of TNF mRNA when stimulated by PMA. TNF production by these cell lines was examined. RPMI 1788 and WIH8 produced little TNF constitutively, but synthesized 5-7 ng/ml TNF when stimulated by PMA. A pre-B cell line, Nalm-6, did not synthesize any detectable amount of TNF mRNA, even with PMA stimulation. Tonsillar B cells could also be stimulated to produce TNF. PMA or Staphylococcus aureus Cowan I strain (SAC) alone stimulated some TNF mRNA accumulation, whereas B cell growth factor (BCGF) or anti-mu did not. This accumulation was synergistically elevated by the combinations of PMA and SAC, or PMA and anti-mu. BCGF increased PMA-, SAC-, PMA plus SAC-, or PMA plus anti-mu-induced TNF mRNA accumulations about twofold. The accumulation of TNF mRNA in tonsillar B cells stimulated by PMA plus SAC was between 32 and 48 h, the same peak interval as the accumulation of TNF and IL-2 mRNA in tonsillar T cells. This is in contrast to PMA or PMA plus A23187-stimulated RPMI 1788 cells in which TNF mRNA accumulation was maximal at 1-2 h. TNF activities found in tonsillar B cell supernatants correlated with the TNF mRNA levels in the cells. However, more TNF activity was found on the second-day than the third-day supernatants, indicating active TNF uptake by the B cells. Cyclosporin A (CsA) inhibited SAC and anti-mu responses in B cells in much the same way as the anti-CD3 responses in T cells. SAC-, PMA plus SAC-, and PMA plus anti-mu-stimulated, but not PMA-stimulated, increases in TNF mRNA accumulations in tonsillar B cells were inhibited by CsA. TNF production seems to increase in parallel with B cell proliferation, but the relationship of these two functions needs to be further examined.
1.1. A rapid DNA affinity purification procedure was worked out for the purification of the Cecropia Immunoresponsive Factor (CIF) from the pupae of Hyalophora cecropia.2.2. CIF consists of a single polypeptide chain of 65 kDA and is present as a homodimer under native conditions.3.3. CIF binds to the κB-like sequences upstream of the H. cecropia immune genes with the following order of affinity: attacin κB >lysozymeκB > cecropin A κB > cecropin B κB.4.4. The purified CIF also strongly binds to the κB sequences from both the immunoglobulin kappa light chain gene and the MHC class I gene.5.5. The DNA binding of CIF can be inhibited by antisera directed against NF-κB-related proteins.6.6. The cytoplasmic factor C1, co-purified from the affinity column, contains two polypeptide chains, one of which has the same molecular weight as CIF.
HTLV-I, the etiological agent in adult T-cell leukemia, has also been strongly implicated in a number of non-neoplastic T-cell-associated diseases. Here, Junji Yodoi and Takashi Uchiyama review these associations and focus on the emerging concepts of IL-2R dysregulation and redox regulation by adult T-cell leukemia-derived factor in the pathogenesis of HTLV-I-related diseases.
Interleukin (IL)-1 induces proliferation and expression of several protooncogenes in the T helper 2 cell line D10A. We have analyzed the signal transmission pathways activated by IL-1 in these cells, leading to the expression of c-jun and c-fos. IL-1 induced c-jun gene transcription and mRNA expression by means of a pathway dependent on protein tyrosine kinase activity since tyrphostin, a specific inhibitor of tyrosine kinase, inhibited this induction. This mechanism of transmission signaling was independent of protein kinase C (PKC) and was linked to the 80-kDa IL-1 receptor (IL-1R). In addition, phorbol esters did not induce c-jun mRNA expression, whereas c-fos mRNA expression mediated by IL-1 dependent on PKC; this pathway was linked to a different, still unidentified IL-1R that was functional in the D10A cell line.
Accumulation of intracellular cAMP generated by IL-1 through the 80-kDa IL-1R negatively regulated c-fos expression which was induced by IL-1 through PKC activation. We conclude that IL-1 modulates the expression of c-fos in D10A cells by occupying of two independent IL-1R that are linked to different signal transduction pathways.
Leukotriene B4 (LTB4) is a notable participant in inflammation and chemotaxis. It is, however, still unclear whether LTB4 acts in this regard directly or indirectly by stimulating the release of chemotactic and inflammatory cytokines. Here we report that LTB4 induces synthesis of interleukin (IL)-6 by human blood monocytes through transcriptional activation of the IL-6 gene. We furthermore demonstrate that this process involves activation of the transcription factor NF-chi B and, to a lesser extent, of NF-IL6, while the activity of the transcription factor AP-1, shown to otherwise confer IL-6 inducibility, appeared to be unaffected by LTB4. Involvement of NF-chi B and NF-IL6 in induction of IL-6 transcription by monocytes was demonstrated using deleted forms of the IL-6 promoter. Activation of the IL-6 promoter by LTB4 was not only associated with accumulation of the respective transcripts but resulted in synthesis of functional IL-6 protein as well. In addition, LTB4 mediated transactivation of a heterologous promoter construct containing the NF-chi B or the NF-IL6 enhancer, but not the AP-1 enhancer. The signaling events mediating this effect appeared to involve the release of H2O2, since LTB4 failed to induce NF-chi B or NF-IL6 in the presence of the scavenger of H2O2, N-acetyl-L-cysteine.
In this paper, we show that both NF-kappa B and the high mobility group protein I(Y) (HMG I(Y)) are required for virus induction of the human interferon-beta (IFN-beta) gene. NF-kappa B binds to the terminal regions of a 10 bp regulatory sequence through contacts in the major groove. while HMG I(Y) recognizes the central region of the same sequence through contacts in the minor groove. Mutations that interfere with binding of either protein decrease the level of virus induction, and activation of the gene can be blocked by either NF-kappa B or HMG I(Y) antisense RNA. HMG I(Y) stimulates the binding of NF-kappa B to the IFN-beta promoter, and it may also function as a promoter-specific accessory factor for NF-kappa B transcriptional activity.
In this paper, we describe a phospholipid transmission pathway mediating tumor necrosis factor (TNF) activation of the nuclear transcription factor kappa B (NF-kappa B). Central to this TNF signaling route is the second messenger-like molecule ceramide, which is generated by sphingomyelin (SM) breakdown catalyzed by a sphingomyelinase (SMase). SMase activation is secondary to the generation of 1,2-diacylglycerol (DAG) produced by a TNF-responsive PC-specific phospholipase C (PC-PLC). The functional coupling of these two C type phospholipases is revealed by D609, a selective inhibitor of PC-PLC. SMase itself, or SMase-inducing regimens such as exogenous PLC or synthetic DAGs, induces NF-kappa B activation at pH 5.0, suggesting the operation of an acidic SMase. A model is proposed in which a TNF-responsive PC-PLC via DAG couples to an acidic SMase, resulting in the generation of ceramide, which eventually triggers rapid induction of nuclear NF-kappa B activity.
A cDNA corresponding to the 2.6 kb NF-kappa B mRNA species present in a variety of lymphoid cell lines has been molecularly cloned. The deduced 607 amino acid sequence is identical to the sequence of the C-terminal region of 110 kd NF-kappa B protein. A 70 kd protein can be identified in lymphoid cells using antibodies raised against the C-terminal region of p110 NF-kappa B. Comparison of the two-dimensional tryptic peptide maps of the 70 kd protein expressed in cells and the in vitro translated product encoded by the cDNA display extensive homology. The 70 kd protein expressed in bacteria prevents sequence-specific DNA binding of p50-p65 NF-kappa B heterodimer, p50 homodimer, and c-rel. p70 also interferes with transactivation by c-rel and prevents its nuclear translocation. The 70 kd protein, predominantly found in lymphoid cells, is a new member of the I kappa B family of proteins and is referred to as I kappa B gamma.
NF-kappa B is an inducible transcription factor comprised of a 50-kD (p50) and a 65-kD (p65) subunit. Induction of NF-kappa B activity, which is a critical event in many signal transduction pathways, involves release from a cytoplasmic inhibitory protein, I kappa B, followed by translocation of the active transcription factor complex into the nucleus. Earlier studies suggested that I kappa B targets the p65 subunit of NF-kappa B. However, we demonstrate by in vitro and in vivo methods that the recently cloned I kappa B/MAD-3 interacts with both the p50 and p65 subunits of NF-kappa B, as well as c-Rel. Furthermore, an alternatively spliced, dimerization-deficient transforming variant of p65 (p65 delta) interacts extremely weakly with I kappa B/MAD-3, suggesting that dimerization is important for interaction. We demonstrate that the conserved nuclear localization sequences (NLSs) of NF-kappa B and c-Rel are the targets for I kappa B/MAD-3 interaction. Indirect immunofluorescence experiments demonstrate that I kappa B/MAD-3 expression retains both p65 and p50 in the cytoplasm. Furthermore, and most important, a p65 that contains an SV40 large T antigen NLS in addition to its own NLS is no longer retained in the cytoplasm in the presence of I kappa B/MAD-3. We propose that I kappa B/MAD-3 masks the NLSs of NF-kappa B and c-Rel and that this constitutes the mechanism for cytoplasmic retention of these proteins.
Markedly decreased plasma cystine and cysteine concentrations have been found in HIV-infected patients at all stages of the disease and in SIV-infected rhesus macaques. The elevated glutamate levels found in the same patients aggravate the cysteine deficiency by inhibiting the membrane transport activity for cystine. The intact immune system appears to require a delicate balance between pro-oxidant and antioxidant conditions, maintained by a limited and well-regulated supply of cysteine. This balance is obviously disturbed in HIV infection and may contribute to the pathogenesis of AIDS.
The gene families encoding the proteins NF-kappa B, c-Rel and Dorsal, in conjunction with their respective inhibitors l kappa B, pp40, and Cactus, achieve specificity in gene regulation by means of common principles. The related activities of NF-kappa B and Dorsal are mediated by heterodimeric or homodimeric complexes of proteins containing the conserved dimerization and DNA-binding domain termed Rel. The l kappa Bs and Cactus, which share a core series of structural repeats termed ankyrin, inhibit cognate activators through differential interactions with the Rel-homology domain. Together, the inhibitory ankyrin proteins and their cognate Rel dimers probably define specific signalling pathways able to activate specific gene expression. Both gene families include proto-oncogenes, thus broadly implicating Rel/l kappa B in the control of both normal gene expression and the aberrant gene expression that makes cells cancerous.
The infection of humans by human immunodeficiency virus type 1 is characterized by a prolonged stage of clinical quiescence. This clinically asymptomatic period may be based, in part, on the development of cell populations within the body that maintain human immunodeficiency virus type 1 in a state of latency. Recent advances in the understanding of the molecular mechanisms involved in various forms of cellular latency of human immunodeficiency virus type 1 have begun to shed light on the variable period of asymptomatic infection. The elucidation of cellular retroviral latency, in vivo, will also be critical to the design of novel therapeutic approaches with which to combat human immunodeficiency virus type 1 infections.
The NF-kappa B transcription factor has been implicated in the inducible expression of many genes, including inflammatory, immune, and acute-phase response genes. NF-kappa B consists of two subunits, 50K and 65K polypeptides. The genes encoding p50 and p65 have sequence similarities with the c-rel proto-oncogene and the Drosophila maternal effect gene dorsal. We describe the cloning and characterization of a novel rel-related gene encoding a 98K product that shares extensive homology with the p105 precursor of the NF-kappa B p50 protein, containing both a Rel homology and SWI6/ankyrin repeat domain. We demonstrate that p98 is proteolytically processed in vivo to generate a 55K polypeptide, which binds to kappa B sites. p55 is capable of forming heterocomplexes with other Rel/NF-kappa B family members, which can bind to kappa B motifs in vitro, and stimulate transcription of reporter genes containing these cis-elements in vivo. The identification of a homolog for NF-kappa B p50/p105, termed p55/p98, gives further support to the idea that NF-kappa B is a collection of structurally related complexes of which contribute to the pleiotropic regulatory processes originally assigned to NF-kappa B.
The candidate oncogene bcl-3 was discovered as a translocation into the immunoglobulin alpha-locus in some cases of B-cell chronic lymphocytic leukaemias. The protein Bcl-3 contains seven so-called ankyrin repeats. Similar repeat motifs are found in a number of diverse regulatory proteins but the motifs of Bcl-3 are most closely related to those found in I kappa B proteins in which the ankyrin repeat domain is thought to be directly involved in inhibition of NF-kappa B activity. No biological function has yet been described for Bcl-3, but it was noted recently that Bcl-3 interferes with DNA-binding of the p50 subunit of NF-kappa B in vitro. Here we demonstrate that Bcl-3 can aid kappa B site-dependent transcription in vivo by counteracting the inhibitory effects of p50/NF-kappa B homodimers. Bcl-3 may therefore aid activation of select NF-kappa B-regulated genes, including those of the human immunodeficiency virus.
Recent studies have indicated that the leukemia inhibitory factor (LIF) induces secretion of interleukin-6 (IL-6) in myeloid cells. We here show that synthesis of IL-6 by human mononuclear phagocytes exposed to recombinant human (rh) LIF is preceded by an increase of IL-6 transcript levels as a result of transcriptional activation of the IL-6 gene. Analysis of deleted fragments of the IL-6 promoter indicated that transcriptional activation of the IL-6 promoter was associated with enhanced binding activity of the transcription factor nuclear factor (NF)-kappa B. Binding of activation protein (AP)-1 and NF-IL-6, also known to transcriptionally activate the IL-6 promoter, was not inducible by LIF. Furthermore, introduction of the NF-kappa B sequence into a heterologous promoter construct, but not of AP-1- and NF-IL-6-binding sequences, conferred inducibility by LIF to this promoter. Deletion of the NF-kappa B binding site in the IL-6 promoter was associated with loss of inducibility by LIF, lending further support for the notion that the NF-kappa B binding site is crucial for LIF-mediated induction of the IL-6 promoter. Taken together, our results show that rhLIF induces IL-6 gene expression in mononuclear phagocytes through transcriptional gene activation involving NF-kappa B.
An oligonucleotide based on the cdc 10/SWI6 repeats of the Drosophila Notch protein was used to isolate other Drosophila genes with these repeats. One of these genes is the cactus locus, 1 of 11 genes required maternally for the establishment in embryos of a gradient of nuclear localization of dorsal protein, a rel-like transcription factor. Previous work showed that in cactus mutants more dorsal protein enters the nucleus in dorsal regions, resulting in a ventralized phenotype. It is now shown that the cactus locus produces two proteins that differ at their carboxy termini; both contain six cdc 10/SWI6 repeats that are sufficient for binding to dorsal and for inhibiting the ability of dorsal to bind DNA. The site on dorsal to which cactus binds was localized to the rel homology domain, where it overlaps with, or is adjacent to, the nuclear localization signal. In vivo the bulk of the cactus protein associated with dorsal is phosphorylated. This, or the association with dorsal, appears to stabilize the maternal cactus protein.
NF-kappa B is a multiprotein complex that can activate a great variety of genes involved in early defence reactions of higher organisms. In nonstimulated cells, NF-kappa B resides in the cytoplasm in an inactive complex with the inhibitor I kappa B. Pathogenic stimuli cause release of I kappa B and allow NF-kappa B to enter the nucleus, bind to DNA control elements and, thereby, induce the synthesis of mRNA. A puzzling feature of NF-kappa B is that its activation is triggered by a great variety of agents. These include the cytokines interleukin-1 and tumor necrosis factor, viruses, double-stranded RNA, endotoxins, phorbol esters, UV light and ionizing radiation. We recently found that also low concentrations of H2O2 activate NF-kappa B and that various antioxidants prevent the induction by H2O2. Subsequent analysis revealed that antioxidants not only suppress the activation of NF-kappa B by H2O2 but by all other inducers tested so far. In this review, we will discuss the evidences that NF-kappa B is an oxidative stress-responsive transcription factor of higher eukaryotic cells.
Acquired immunodeficiency syndrome (AIDS) results from infection with a human immunodeficiency virus (HIV). The long terminal repeat (LTR) region of HIV proviral DNA contains binding sites for nuclear factor kappa B (NF-kappa B), and this transcriptional activator appears to regulate HIV activation. Recent findings suggest an involvement of reactive oxygen species (ROS) in signal transduction pathways leading to NF-kappa B activation. The present study was based on reports that antioxidants which eliminate ROS should block the activation of NF-kappa B and subsequently HIV transcription, and thus antioxidants can be used as therapeutic agents for AIDS. Incubation of Jurkat T cells (1 x 10(6) cells/ml) with a natural thiol antioxidant, alpha-lipoic acid, prior to the stimulation of cells was found to inhibit NF-kappa B activation induced by tumor necrosis factor-alpha (25 ng/ml) or by phorbol 12-myristate 13-acetate (50 ng/ml). The inhibitory action of alpha-lipoic acid was found to be very potent as only 4 mM was needed for a complete inhibition, whereas 20 mM was required for N-acetylcysteine. These results indicate that alpha-lipoic acid may be effective in AIDS therapeutics.
The NF-kappa B subunits p50 and p65 and the product of the rel proto-oncogene are members of a growing class of transcription factors with a unique DNA-binding and dimerization domain. Nuclear transfer of each of these factors is controlled by cytoplasmic inhibitors, and regulated by specific stimuli. The inhibitors I kappa B-alpha and -beta and pp40 recognize either p65 or the c-rel protein. We show here that the proto-oncogene bcl-3, believed to be involved in certain human B-cell leukaemias, encodes a protein that functions as an I kappa B-like molecule for native NF-kappa B but is specific for the p50 subunit. The ankyrin repeat domain of the bcl-3 product is shown to mediate complex formation with NF-kappa B dimers by contracting the conserved dimerization domain of NF-kappa B.
Molecular cloning of the subunits of the transcription factor NF-kappa B and its inhibitor l kappa B revealed regions of sequence homology with two different classes of proteins: the Rel/dorsal family and a heterogeneous group of proteins containing ankyrin-like repeats. Both the Rel/dorsal homology domain and the ankyrin-like repeats appear to play important roles in protein-protein interactions that regulate localization and activity of the NF-kappa B subunits.
Molecular cloning of the polypeptide component of the Rel-related human p75 nucleoprotein complex has revealed its identity with the 65-kDa (p65) subunit of NF-kappa B. Functional analyses of chimeric proteins composed of NF-kappa B p65 C-terminal sequences linked to the DNA-binding domain of the yeast GAL4 polypeptide have indicated that the final 101 amino acids of NF-kappa B p65 comprise a potent transcriptional activation domain. Transient transfection of human T cells with an expression vector encoding NF-kappa B p65, but not NF-kappa B p50, produced marked transcriptional activation of a basal promoter containing duplicated kappa B enhancer motifs from the long terminal repeat of type 1 human immunodeficiency virus. These stimulatory effects of NF-kappa B p65 were synergistically enhanced by coexpression of NF-kappa B p50 but were completely inhibited by coexpression of the v-rel oncogene product. Together, these functional studies demonstrate that NF-kappa B p65 is a transactivating subunit of the heterodimeric NF-kappa B complex and serves as one cellular target for v-Rel-mediated transcriptional repression.
The nuclear factor that binds to the kappa light-chain enhancer of B cells (NF-kappa B) is a transcription factor that regulates the expression of a variety of cellular and viral genes. NF-kappa B is composed of distinct subunits, and at least four independent genes (p105, p100, p65, and c-rel) have been isolated that encode related proteins that bind kappa B sites. Because it is possible that specific interactions of different subunits can allow selective gene activation, we have characterized the specificity of transcriptional activation by various combinations of these subunits. When tested alone, an approximately 49-kDa form (p49) of the p100 protein bound weakly to kappa B, but p49 associated with p65 to bind efficiently to this site. Furthermore, p49 acted in combination with either p65 or a Rel/VP16 fusion protein to activate kappa B-dependent transcription in Jurkat T leukemia cells. The p49/p65 or p49/Rel combination stimulated transcription mediated by the canonical kappa B site but did not stimulate reporter genes containing interleukin 2 receptor alpha or major histocompatibility complex kappa B elements, despite its ability to bind to these sites. Transactivation mediated by the p49/p100 and p65 NF-kappa B proteins is therefore sensitive to minor changes in the sequence of the kappa B site. Specificity determined by the association of NF-kappa B subunits provides a mechanism to selectively regulate variant kappa B sites associated with different cellular and viral genes.
The mechanism by which interleukin-1 alpha (IL-1 alpha) activates NF-kappa B DNA-binding activity is not completely understood. While it is well established that protein kinase C can activate NF-kappa B, neither protein kinase C nor protein kinase A appears to be critical in the induction of NF-kappa B by IL-1 alpha. Since a number of growth factors signal via protein tyrosine kinase, in this study we examined a possible involvement of protein tyrosine kinase in the IL-1 alpha-induced NF-kappa B. The results showed that in the murine pre-B cell line 70Z/3 and in the murine T cell line EL-4 6.1 C10 IL-1 alpha-induced NF-kappa B was associated with transient increase in protein tyrosine kinase activity. Pre-treatment of these cell lines with herbimycin A, an inhibitor of tyrosine kinase activity, blocked the IL-1 alpha-enhanced protein tyrosine kinase activity and the IL-1 alpha-induced NF-kappa B DNA-binding activity. Herbimycin A at concentrations sufficient to block IL-1 alpha-induced NF-kappa B did not block the phorbol 12-myristate 13-acetate (PMA)-induced NF-kappa B. The data suggest that IL-1 alpha and PMA activate NF-kappa B by different pathways and that induction of NF-kappa B DNA-binding activity by IL-1 might be dependent on protein tyrosine phosphorylation.
We show that the non-DNA-binding precursor for the p50 subunit (p110), like NF-kappa B, is subject to control of nuclear uptake. In contrast to p50, p110 was excluded from nuclei and unable to associate detectably with p50 or p65 NF-kappa B subunits. The nuclear location signal in the N-terminal half of p110 was not accessible for monospecific antibodies. Removal of only 191 amino acids from the C-terminus of p110 restored antibody accessibility as well as nuclear uptake. The C-terminal half of p110, which is linked to the p50 portion via a glycine-rich hinge, could also noncovalently bind to p50. This helps to explain why p50, after cleavage of the precursor in intact cells, was still retained in an inactive form in the cytoplasm. Our study describes a novel mechanism of nuclear uptake control by masking of a nuclear location signal through a remote domain within a precursor molecule.
Transcription factor NF-kappa B comprises two proteins, p50 and p65, that have sequence similarity to the v-rel oncogene. In primary hematopoietic cell populations an alternatively spliced form of NF-kappa B p65 mRNA was observed that encoded a protein designated p65 delta. Expression of the p65 delta cDNA in Rat-1 fibroblasts resulted in focus formation, anchorage-independent growth in soft agar, and tumor formation in athymic nude mice, effects not obtained with expression of p65 or a p65 delta mutant that contains a disruption within the transcriptional activation domain. Thus, p65 delta, which associated weakly and interfered with DNA binding by p65, may sequester an essential limiting regulatory factor or factors required for NF-kappa B function.
The molecular mechanisms underlying the pathophysiology of bone destruction still remain poorly understood. We have found that hydrogen peroxide (H2O2), a reactive oxygen species (ROS), is a potent stimulator of osteoclastic bone resorption and cell motility. A marked enhancement of bone resorption was noted when rat osteoclasts, cultured on devitalised bovine cortical bone, were exposed to 10 nM [H2O2]. Apart from exposing osteoclasts to a low extracellular pH, which is known to enhance osteoclastic bone resorption, we provide first evidence for a molecule that stimulates osteoclastic bone resorption in osteoclast cultures that do not respond to parathyroid hormone and 1, 25 dihydroxyvitamin D3. We envisage that both basic biological and practical clinical implications may eventually follow from these studies.
Recombinant subunits of the transcription factor NF-kappa B, p50 and p65, were analyzed both for binding to various kappa B motifs and in vitro activation. The subunits preferentially form a heterodimer that activates transcription. Although p50 and p65 bind DNA individually as homodimers and are structurally related, their activation mechanisms are distinct. p65 activates transcription by its unique carboxy-terminal activation domain. (p50)2 displays higher affinity DNA binding than (p65)2 for many distinct kappa B motifs and provides strong transcriptional activation only when adopting a chymotrypsin-resistant conformation induced by certain kappa B motifs but not others. Thus, (p50)2 acts as a positive regulator in vitro, consistent with its isolation as a putative constitutive regulator of MHC class I genes. Both subunits of NF-kappa B, therefore, contribute independently to provide regulation at given kappa B motifs.
Regulation of interleukin-2 (IL-2) gene expression by the p50 and p65 subunits of the DNA binding protein NF-kappa B was studied in nontransformed CD4+ T lymphocyte clones. A homodimeric complex of the NF-kappa B p50 subunit was found in resting T cells. The amount of p50-p50 complex decreased after full antigenic stimulation, whereas the amount of the NF-kappa B p50-p65 heterodimer was increased. Increased expression of the IL-2 gene and activity of the IL-2 kappa B DNA binding site correlated with a decrease in the p50-p50 complex. Overexpression of p50 repressed IL-2 promoter expression. The switch from p50-p50 to p50-p65 complexes depended on a protein that caused sequestration of the p50-p50 complex in the nucleus.
The subcellular localization of the mouse Ltk transmembrane protein tyrosine kinase was studied in transfected COS cells, a mature B lymphocyte line, and a low expressing transfected lymphocyte clone. Indirect immunofluorescence and immunogold staining of COS transfectants and endoglycosidase analysis of both COS transfectants and lymphocytes indicate the unusual localization of Ltk to the endoplasmic reticulum (ER). Ltk resembles a receptor tyrosine kinase; it has a short, glycosylated, and cysteine-rich N-terminal domain. Yet, it appears to function in a ligand-independent mechanism: its in vivo catalytic activity is markedly enhanced by alkylating and thiol-oxidizing agents, and the active fraction of the protein occurs as disulfide-linked multimers. The catalytic activity of Ltk in the ER may be regulated via changes in the cellular redox potential, a novel mechanism for regulating protein tyrosine kinases. The ability to respond to redox changes in the cell may, however, be shared with certain receptor kinases during their passage through the ER.
The endothelial leukocyte adhesion molecule 1 (ELAM-1) is transiently expressed specifically on the surface of cytokine-Induced
endothelial cells. We demonstrate that the transient expression of the protein is paralleled by an Increase and decrease In
transcription of the ELAM-1 gene. To Identify the clsacting transcription control regions within the ELAM-1 gene that are
responsible for this cytokine-induced expression, we Isolated and analyzed an ELAM-1 genomic clone containing sequences upstream
of the transcription start site. We constructed a series of ELAM-1 deletion mutants linked to a reporter gene and analyzed
their expression In both endothelial and nonendothelial cells. Results show that a fragment of 233 bp upstream of the transcription
start site Is sufficient to confer cytokine Inducibility upon the reporter gene In both endothelial and non-endothelial cells.
Further analysis defined two elements within this region that are involved In the cytokine inducibility of the ELAM-1 gene.
One element lies within the −233 to −117 region, the other element represents an NFxB consensus binding site between nucleotides −94 to −85. Gel shift analysis reveals increased binding of an NFxB-like factor to this consensus sequence in extracts prepared from IL-1-induced endothelial cells. The results suggest that
cytokine induction of ELAM-1 gene transcription is imparted by a combination of positive factors, one being an NFxB-like transcription factor, interacting with cis-acting elements within the enhancer/promoter of the gene.
A B cell lymphoma-associated chromosomal translocation, t(10;14)(q24;q32), juxtaposes the immunoglobulin C alpha 1 locus to a novel gene, lyt-10. The normal lyt-10 cDNA codes for a 98 kd protein which displays amino-terminal homology with the rel (DNA-binding) domain of the NF-kappa B-rel family of transcription factors and carboxy-terminal homology with the NF-kappa B p50 precursor protein, including the putative proteolytic cleavage domain (poly-G) and the ankyrin-like repeat domains. The lyt-10 protein can bind to kappa B sequences in vitro, although with different specificity from NF-kappa B p50, and in vitro DNA-binding is activated by removal of the ankyrin domain. Chromosomal translocation generates an lyt-10-C alpha 1 fusion gene coding for a protein that retains the rel effector domain, lacks the ankyrin regulatory domain, and binds kappa B sequences in vitro, suggesting its constitutive activation in vivo. Analogous rearrangements of the lyt-10 gene have been found in an additional three cases of lymphoid neoplasia. The lyt-10 gene defines a new subfamily (rel/poly-G/ankyrin) of NF-kappa B-rel transcription factors with potential for oncogenic activation in human cancer.
We have cloned a group of cDNAs representing mRNAs that are rapidly induced following adherence of human monocytes. One of the induced transcripts (MAD-3) encodes a protein of 317 amino acids with one domain containing five tandem repeats of the cdc10/ankyrin motif, which is 60% similar (46% identical) to the ankyrin repeat region of the precursor of NF-kappa B/KBF1 p50. The C-terminus has a putative protein kinase C phosphorylation site. In vitro translated MAD-3 protein was found to specifically inhibit the DNA-binding activity of the p50/p65 NF-kappa B complex but not that of the p50/p50 KBF1 factor or of other DNA-binding proteins. The MAD-3 cDNA encodes an I kappa B-like protein that is likely to be involved in regulation of transcriptional responses to NF-kappa B, including adhesion-dependent pathways of monocyte activation.
Analysis of the heteromeric DNA binding protein GABP has revealed the interaction of two distinct peptide sequence motifs
normally associated with proteins located in different cellular compartments. The alpha subunit of GABP contains an 85-amino
acid segment related to the Ets family of DNA binding proteins. The ETS domain of GABP alpha facilitates weak binding to DNA
and, together with an adjacent segment of 37 amino acids, mediates stable interaction with GABP beta. The beta subunit of
GABP contains four imperfect repeats of a sequence present in several transmembrane proteins including the product of the
Notch gene of Drosophila melanogaster. These amino-terminal repeats of GABP beta mediate stable interaction with GABP alpha
and, when complexed with GABP alpha, directly contact DNA. These observations provide evidence for a distinct biochemical
role for the 33-amino acid repeats, and suggest that they may serve as a module for the generation of specific dimerization
interfaces.
The Rel-associated protein pp40 is functionally related to I kappa B, an inhibitor of the transcription factor NF-kappa B.
Purified pp40 inhibits the DNA binding activity of the NF-kappa B protein complex (p50:p65 heterodimers), p50:c-Rel heteromers,
and c-Rel homodimers. The sequence of the complementary DNA encoding pp40 revealed similarity to the gene encoding MAD-3,
a protein with mammalian I kappa B-like activity. Protein sequencing of I kappa B purified from rabbit lung confirmed that
MAD-3 encodes a protein similar to I kappa B. The sequence similarity between MAD-3 and pp40 includes a casein kinase II and
consensus tyrosine phosphorylation site, as well as five repeats of a sequence found in the human erythrocyte protein ankyrin.
These results suggest that rel-related transcription factors, which are capable of cytosolic to nuclear translocation, may
be held in the cytosol by interaction with related cytoplasmic anchor molecules.