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Cloning of BRAK, a Novel Divergent CXC Chemokine Preferentially Expressed in Normal versus Malignant Cells
Abstract
Chemokines are a family of related proteins that regulate leukocyte infiltration into inflamed tissue and play important roles in many disease processes. Chemokines are divided into two major groups, CC or CXC, based on their sequence around the amino terminal cysteines. We report the PCR cloning of a novel human chemokine termed BRAK for its initial isolation from breast and kidney cells. This novel chemokine is distantly related to other CXC chemokines (30% identity with MIP-2alpha and beta) and shares several biological activities. BRAK is expressed ubiquitously and highly in normal tissue. However, it was expressed in only 2 of 18 cancer cell lines. BRAK is located on human chromosome 5q31.
... CXCL14 was first identified and cloned by Hromas et al. 6 showing 30% identity and 55% similarity with CXCL1, CXCL2, and CXCL8, which bind to the common chemokine receptor CXCR2 (Figure 2A,B). ...
... In fact, mature human CXCL14 differs from murine CXCL14 at only two amino acids. 6 Among mammals, CXCL14 has a unique five amino acid insertion (V/M-S-R-Y-R) which is not present in reptilian CXCL14 nor any other CXC chemokines ( Figure 2B). 6,10 This VSRYR motif is recognized as a destruction box that is necessary and sufficient for ubiquitination and proteasomal degradation of CXCL14. ...
... 6 Among mammals, CXCL14 has a unique five amino acid insertion (V/M-S-R-Y-R) which is not present in reptilian CXCL14 nor any other CXC chemokines ( Figure 2B). 6,10 This VSRYR motif is recognized as a destruction box that is necessary and sufficient for ubiquitination and proteasomal degradation of CXCL14. 10 Interestingly, CXCL14 is efficiently degraded by ubiquitin-mediated proteolysis in cancer and immortalized cells, but not in normal epithelial cells. ...
The chemokine CXCL14 is a highly conserved, homeostatic chemokine that is constitutively expressed in skin epithelia. Responsible for immune cell recruitment and maturation, as well as impacting epithelial cell motility, CXCL14 contributes to the establishment of immune surveillance within normal epithelial layers. Furthermore, CXCL14 is critical to upregulating major histocompatibility complex class I expression on tumor cells. Given these important roles, CXCL14 is often dysregulated in several types of carcinomas including cervical, colorectal, endometrial, and head and neck cancers. Its disruption has been shown to limit critical antitumor immune regulation and is correlated to poor patient prognosis. However, other studies have found that in certain cancers, namely pancreatic and some breast cancers, overexpression of stromal CXCL14 correlates with poor patient survival due to increased invasiveness. Contributing to the ambiguity CXCL14 plays in cancer is that the native CXCL14 receptor remains uncharacterized, although several candidate receptors have been proposed. Despite the complexity of CXCL14 functions, it remains clear that this chemokine is a key regulatory factor in cancer and represents a potential target for future cancer immunotherapies.
... CXCL14 is a small cytokine that belongs to the CXC-motif chemokine subfamily. It has been first isolated from human cell lines (Frederick et al., 2000;Hromas et al., 1999). The chemokine was first named BRAK, due to its isolation from breast and kidney cell lines. ...
... CXCL14 presents specific characteristics that differs from the other chemotactic cytokines such as an unusual short N-terminal part of only two amino acids upstream the first conserved cysteine residue and five consecutive additional amino acids (Hromas et al., 1999;Peterson et al., 2007 Gordon et al., 2011;Long et al., 2000;Ojeda et al., 2013;Park et al., 2009), suggesting that CXCL14 might be involved in different developmental processes. At adult stage, CXCL14 is observed in skin, brain, intestine, kidney, white adipose tissue (WAT), immune cells and some tumour cells (Hromas et al., 1999;Nara et al., 2007), highlighting CXCL14 as a likely pleiotropic chemokine. ...
... CXCL14 presents specific characteristics that differs from the other chemotactic cytokines such as an unusual short N-terminal part of only two amino acids upstream the first conserved cysteine residue and five consecutive additional amino acids (Hromas et al., 1999;Peterson et al., 2007 Gordon et al., 2011;Long et al., 2000;Ojeda et al., 2013;Park et al., 2009), suggesting that CXCL14 might be involved in different developmental processes. At adult stage, CXCL14 is observed in skin, brain, intestine, kidney, white adipose tissue (WAT), immune cells and some tumour cells (Hromas et al., 1999;Nara et al., 2007), highlighting CXCL14 as a likely pleiotropic chemokine. The expression of CXCL14 reveals a homeostatic rather than inflammatory role, during development and at adult stages. ...
Skeletal muscle development mostly relies on intrinsic capacities of muscle progenitors to proliferate and differentiate. However, extrinsic signals arising from non-myogenic cells also contribute to the establishment of functional skeletal muscles. The aim of this PhD project was to investigate the role of connective-tissue (CT) on the development of skeletal muscle, using the chick embryonic limb as a model. We particularly investigated the influence of the two chemokines CXCL12 and CXCL14, which have been previously shown as expressed in limb mesenchyme giving rise to the different types of CTs during development. The involvement of CXCL12 and CXCL14 in limb CT differentiation was studied, as well as the role of these chemokines in skeletal muscle development mediated by CT. We first showed that CXCL12 and CXCL14 display distinct restricted expression patterns in limb CT of chick embryos and demonstrated that CXCL12 promotes the expression of OSR1, OSR2 and COL3A1 genes, three markers of irregular CT, while CXCL14 enhances the expression of a regular CT gene, SCX. In addition, the expression of CXCL12, CXCL14 and their putative CT target genes were all negatively regulated by the anti-fibrotic BMP signalling, but also in the absence of musculoskeletal mechanical forces. These results show for the first time the involvement of CXCL12 and CXCL14 chemokines in the differentiation of CTs. The putative role of both chemokines on CT-mediated myogenesis was then analysed. We observed that CXCR7, one CXCL12 receptor, was expressed both in muscle progenitors and differentiated muscle cells in embryonic chick limbs. Using gain- and loss-of-function approaches in primary cultures of chick limb myoblasts, we revealed that CXCR7 promoted myogenesis by regulating muscle cell fusion, while CXCL12 did not influence muscle differentiation. CXCL14 dramatically inhibits in vitro myogenesis. Functional assays performed in chick embryonic forelimbs in vivo demonstrate that overexpression of CXCL12, CXCR7 or a dominant-negative form of CXCR7 all resulted in abnormal and mispatterned muscles in chick limbs. Similarly, CXCL14 overexpression in chick limb in vivo led to profound anomalies in muscle differentiation. All together, our results demonstrate an essential contribution of CXCL12 and CXCL14 chemokines in CT differentiation and in CTmediated muscle development in embryonic limb.
... CXCL14, a homeostatic chemokine in squamous epithelia, is known for its association with cancer as being abundantly expressed in normal tissue but significantly downregulated in some tumors [28,29]. High levels of CXCL14 expression are correlated with overall patient survival in colorectal, breast, endometrial, intraepithelial, and head and neck cancers [30] and suppress tumor progression [31][32][33][34][35]. ...
... Because each method has clear advantages and disadvantages, as previously documented [80][81][82][83], effective CXCL14 delivery may depend on these technical limitations and patients' circumstances (e.g., immunocompromised condition). For instance, the direct application of recombinant CXCL14 protein may be challenged by the lack of posttranslational modifications required for its proper functions [28,84]. Nanoparticles and liposomes have been shown to be effective in previous cancer therapies but are still limited by their route of administration and biodistribution [85]. ...
There is great enthusiasm toward the development of novel immunotherapies for the treatment of cancer, and given their roles in immune system regulation, chemokines stand out as promising candidates for use in new cancer therapies. Many previous studies have shown how chemokine signaling pathways could be targeted to halt cancer progression. We and others have revealed that the chemokine CXCL14 promotes antitumor immune responses, suggesting that CXCL14 may be effective for cancer immunotherapy. However, it is still unknown what mechanism governs CXCL14-mediated antitumor activity, how to deliver CXCL14, what dose to apply, and what combinations with existing therapy may boost antitumor immune responses in cancer patients. Here, we provide updates on the role of CXCL14 in cancer progression and discuss the potential development and application of CXCL14 as an immunotherapeutic agent.
... CXCL14 (also known as breast and kidney-expressed chemokine (BRAK)), as a non-ELR CXC chemokine, is considered a relatively newlyidentified chemokine in the CXC family. Among chemokines, CXCL14 is highly conserved in mammals with only two amino acids difference between mice and humans [7]. Like other chemokines, CXCL14 is a chemoattractant, especially for monocytes, and induces maturation and migration of dendritic cells (DCs). ...
... Despite the structural similarity of CXCL14 to CXCL1, 2, and 8, this chemokine does not interact with CXCR2 (a common receptor for CXCL1, 2, and 8), and CXCL14 receptor has not yet been fully understood [7]. However, there are three proposed receptors for CXCL14 binding. ...
Cancer is a leading cause of death worldwide and imposes a substantial financial burden. Therefore, it is essential to develop cost-effective approaches to inhibit tumor growth and development. The imbalance of cytokines and chemokines play an important role among different mechanisms involved in cancer development. One of the strongly conserved chemokines that is constitutively expressed in skin epithelia is the chemokine CXCL14. As a member of the CXC subfamily of chemokines, CXCL14 is responsible for the infiltration of immune cells, maturation of dendritic cells, upregulation of major histocompatibility complex (MHC)-I expression, and cell mobilization. Moreover, dysregulation of CXCL14 in several cancers has been identified by several studies. Depending on the type or origin of the tumor and components of the tumor microenvironment, CXCL14 plays a conflicting role in cancer. Although fibroblast-derived CXCL14 has a tumor-supportive role, epithelial-derived CXCL14 mainly inhibits tumor progression. Hence, this review will elucidate what is known on the mechanisms of CXCL14 and its therapeutic approaches in tumor treatment. CXCL14 is a promising approach for cancer immunotherapy.
... Accumulating evidence highlights the importance of the secretory factors from adipocytes, called adipokines, interacting with other organs and regulating metabolic homeostasis 2 . In recent decades, numerous adipose tissue (WAT) and BAT [5][6][7] . Although neither the cellular receptor nor the signaling pathway of CXCL14 has yet been definitively identified, this chemokine reportedly exerts chemotactic activity on various inflammatory mononuclear cells, including monocytes, neutrophils, dendritic cells and natural killer cells 8 . ...
... CXCL14 was first identified from breast and kidney cells 5 . It is considered to exert pleiotropic functions as an immune and inflammatory modulator on various target cells, contributing to chemotaxis, cell differentiation and angiogenesis 8 . ...
Aims/Introduction
Recent studies have suggested C‐X‐C motif chemokine ligand 14 (CXCL14), secreted from adipose tissue, to play an important role in the pathogenesis of metabolic syndrome. However, the clinical significance of CXCL14 in humans has not been elucidated. This study aimed to assess correlations between serum CXCL14 levels and clinical parameters in patients with type 2 diabetes mellitus.
Materials and Methods
In total, 176 individuals with type 2 diabetes mellitus were recruited. Serum CXCL14 concentrations were determined by enzyme‐linked immunosorbent assay. We examined the associations of serum CXCL14 levels with laboratory values, abdominal computed tomography image information, surrogate markers used for evaluating the pathological states of diabetes, obesity and atherosclerosis.
Results
Serum CXCL14 levels correlated positively with body mass index, waist circumference, subcutaneous and visceral fat areas, and serum alanine transaminase, uric acid, total cholesterol, low‐density lipoprotein cholesterol, triglycerides and C‐peptide (CPR) levels. In contrast, CXCL14 levels correlated inversely with age, pulse wave velocity and serum adiponectin levels. Multiple linear regression analysis showed serum levels of CPR (β = 0.227, P = 0.038) and the fatty liver index (β = 0.205, P = 0.049) to be the only parameters showing independent statistically significant associations with serum CXCL14 levels.
Conclusions
Serum CXCL14 levels were independently associated with serum CPR and fatty liver index in patients with type 2 diabetes mellitus. In these patients, a high serum CPR concentration might reflect insulin resistance rather than β‐cell function, because CXCL14 showed simple correlations with obesity‐related parameters. Collectively, these data suggested that serum CXCL14 levels in type 2 diabetes patients might be useful predictors of elevated serum CPR and hepatic steatosis.
... CXCL14 is a relatively novel non-ELR (glutamic acidleucine-arginine) chemokine with broad biological activities [10]. CXCL14 was initially identified from kidney and breast cells and has been reported to be widely expressed in normal tissue [10,11]. ...
... CXCL14 is a relatively novel non-ELR (glutamic acidleucine-arginine) chemokine with broad biological activities [10]. CXCL14 was initially identified from kidney and breast cells and has been reported to be widely expressed in normal tissue [10,11]. The mechanisms governing the expression of CXCL14 and CXCL14-mediated functions are incompletely understood. ...
Ventilator-induced lung injury (VILI) is one of the most common complications of mechanical ventilation (MV), which strongly impacts the outcome of ventilated patients. Current evidences indicated that inflammation is a major contributor to the pathogenesis of VILI. Our results showed that MV induced excessive proinflammatory cytokine productions together with decreased CXCL14 and increased PKM2 expressions in injured lungs. In addition, CXCL14 overexpression downregulated PKM2 expression and attenuated VILI with reduced inflammation. Moreover, the overexpression of PKM2 markedly diminished the protective effects of CXCL14 against VILI as reflected by worsened morphology and increased cytokine production, whereas PKM2 knockdown decreased cytokine production and attenuated VILI. Collectively, these results suggested that CXCL14 overexpression attenuates VILI through the downregulation of PKM2-mediated proinflammatory cytokine production.
... In contrast, the expression levels of the tissue inhibitor of matrix metalloproteinase 3 (TIMP3), which inhibits the activity of various MMPs, and insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), which suppresses the activities of IGF-1 and-2 by binding to these growth factors with high affinity, were significantly down-regulated. However, the down-regulation of the chemokine CXCL14 [8] was the most prominent [7]. ...
... CXCL14, also called BRAK because it was initially found to be expressed in the breast and kidneys [8], is ubiquitously and abundantly expressed in almost all cell types, particularly epithelial cells, and was found to be significantly down-regulated in our model system. Thus, our data suggested that CXCL14 could act as a tumor suppressor. ...
Cancer is a leading cause of death and disease worldwide, with a tremendous financial impact. Thus, the development of cost-effective novel approaches for suppressing tumor growth and progression is essential. In an attempt to identify the mechanisms responsible for tumor suppression, we screened for molecules downregulated in a cancer progression model and found that the chemokine CXCL14, also called BRAK, was the most significantly downregulated. Increasing the production of CXCL14 protein by transfecting tumor cells with a CXCL14 expression vector and transplanting the cells into the back skin of immunodeficient mice suppressed tumor cell growth compared with that of parental tumor cells, suggesting that CXCL14 suppressed tumor growth in vivo. However, some studies have reported that over-expression of CXCL14, especially in stromal cells, stimulated the progression of tumor formation. Transgenic mice expressing 10-fold more CXCL14 protein than wild-type C57BL/6 mice showed reduced rates of chemical carcinogenesis, transplanted tumor growth, and metastasis without apparent side effects. CXCL14 also acts as an antimicrobial molecule. In this review, we highlight recent studies involving the identification and characterization of CXCL14 in cancer progression and discuss the reasons for the context-dependent effects of CXCL14 on tumor formation.
... High expression levels of several inflammation-related genes have been identified in prostate, gastric and colon cancer (Schwarze et al. 2005;Friederichs et al. 2005;Niwa et al. 2010;Doll et al. 2010). However, several studies showed low or absent expression of inflammation-related genes in breast cancer (Hromas et al. 1999;Basolo et al. 1993;Cao et al. 2013). The role of chemokines in tumor biology is complex; some chemokines act as angiogenic and tumor-promoting proteins, whereas others are angiostatic and inhibit tumor development. ...
... It is associated with immune response and is an important factor in inhibition of carcinogenesis (Doll et al. 2010). Therefore, downregulation of CXCL2 may promote immune escape of cancer cells (Hromas et al. 1999;Basolo et al. 1993;Cao et al. 2013). Moreover, previous studies examined the role of CXCL2 in HCC and the regulation of its expression by miRNAs. ...
Purpose
Recent genetic studies have suggested that tumor suppressor genes are often silenced during carcinogenesis via epigenetic modification caused by methylation of promoter CpG islands. Here, we characterized genes inactivated by DNA methylation in human hepatocellular carcinoma (HCC) to identify the genes and pathways involved in DNA methylation in hepatocellular carcinoma.
Methods
Eight HCC-derived cell lines were treated with a DNA demethylating agent, 5-aza-2′-deoxycytidine. Additionally, 100 pairs of primary HCC and adjacent non-cancerous tissues as well as 15 normal liver tissues were analyzed by comprehensive gene expression analysis using microarrays. Moreover, gene set enrichment analysis identified the major molecular pathways associated with DNA methylation. Validation of gene expression and DNA methylation status was performed by real-time PCR after bisulfite modification.
Results
We showed that CXCL2, an immune-related chemokine, expression was significantly downregulated in tumor tissues and also significantly upregulated by DAC treatment in cell lines. Furthermore, we observed a statistically significant difference in methylation status between normal liver tissues and tumor tissues (P < 0.05). In addition, tumors with higher CXCL2 expression included significantly more numbers of multiple tumors than the lower expression group.
Conclusions
We identified CXCL2, an immune-related chemokine, decreased in hepatocellular carcinoma and the regulation mechanism may be controlled by methylation. Further studies should be warranted to examine if and to what extent the gene is actually suppressed by methylation and if there is a possibility that the CXCL2 axis plays a role for diagnosis and treatment of hepatocellular carcinoma.
... [10][11][12] It is related to infiltration of immune cells, cell mobilization, maturation of dendritic cells, and increased expression of the major histocompatibility complex I (MHC-I) molecules. [13][14][15] Although the prognostic value of CXCL14 is inconsistent among different cancers, [16][17][18][19][20] growing evidence demonstrates its place in the regulation of TIME. In glioma, the expression of CXCL14 by tumor cells has been shown to enhance the chemotaxis of cytotoxic T cells, boost CD8+ T-cell response, and improve overall survival (OS). ...
Background
Epigenetic mechanisms play vital roles in the activation, differentiation, and effector function of immune cells. The breast and kidney-expressed chemokine (CXCL14) mainly contributes to the regulation of immune cells. However, its role in shaping the tumor immune microenvironment (TIME) is yet to be elucidated in renal cell carcinoma (RCC).
Objectives
This study aimed to elucidate the role of CXCL14 in predicting the efficacy of immunotherapy in patients with RCC.
Methods
CXCL14 expression and RNA-sequencing, single-cell RNA-sequencing (scRNA-seq), and survival datasets of RCC from public databases were analyzed, and survival was compared between different CXCL14 levels. The correlation between CXCL14 and immune infiltration and human leukocyte antigen (HLA) gene expression was analyzed with TIMER2.0 and gene expression profiling interactive analysis. Institutional scRNA-seq and immunohistochemical staining analyses were used to verify the relationship between CXCL14 expression level and the efficacy of immunotherapy.
Results
CXCL14 was expressed in fibroblast and malignant cells in RCC, and higher expression was associated with better survival. Enrichment analysis revealed that CXCL14 is involved in immune activation, primarily in antigen procession, antigen presentation, and major histocompatibility complex assemble. CXCL14 expression was positively correlated with T-cell infiltration as well as HLA-related gene expression. Among the RCC cohort receiving nivolumab in Checkmate 025, the patients with CXCL14 high expression had better overall survival than those with CXCL14 low expression after immunotherapy. scRNA-seq revealed a cluster of CXCL14+ fibroblast in immunotherapy responders. Immunohistochemistry analysis verified that the patients with high CXCL14 expression had an increased proportion of high CD8 expression simultaneously. The expression level of CXCL14 was associated with CXCR4 expression in RCC.
Conclusion
CXCL14 expression is associated with immunotherapy response in RCC. It is a promising biomarker for immunotherapy response prediction and may be an effective epigenetic modulator in combination with immunotherapy approaches.
... CXCL14, originally named the breast and kidney expressed chemokine (BRAK), is a non-ELR chemokine [114]. CXCL14 is a monocyte chemoattractant and induces DC maturation and migration. ...
Lung cancer is a rapidly progressing disease with a poor prognosis. Bone metastasis is commonly found in 40.6% of advanced-stage patients. The mortality rate of lung cancer patients with bone metastasis can be significantly decreased by implementing novel diagnostic techniques, improved staging and classification systems, precise surgical interventions, and advanced treatment modalities. However, it is important to note that there is currently a lack of radical procedures available for these patients due to the development of drug resistance. Consequently, palliative care approaches are commonly employed in clinical practice. Therefore, new un-derstandings of the process of bone metastasis of lung cancer are critical for developing better treatment strategies to improve patient's clinical cure rate and quality of life. Chemokines are cell-secreted small signaling proteins in cancer occurrence, proliferation, invasion, and metastasis. In this study, we review the development of bone metastasis in lung cancer and discuss the mechanisms of specific chemokine families (CC, CXC, CX3C, and XC) in regulating the biological activities of tumors and promoting bone metastasis. We also highlight some preclinical studies and clinical trials on chemokines for lung cancer and bone metastasis.
... Using differential gene expression analysis, we found that CXCL14 was downregulated after treatment. CXCL14 is normally expressed in high levels in benign cells, but the expression is mostly reduced or completely absent in malignant cells (Hromas et al. 1999). The role of CXCL14 is known to be associated with the attraction and maturation of immune cells and the local infiltration of dendritic cells (Shurin et al. 2005). ...
Purpose:
In this study, we aim to investigate gene expression changes in tumor samples obtained from patients with esophageal cancer treated with calcium electroporation. Previously, local treatment with calcium electroporation has been shown to induce gene expression alterations, potentially contributing to a more tumor-hostile microenvironment.
Methods:
In this sub-study of a phase I clinical trial, we included five patients with esophageal cancer treated with calcium electroporation. We compared cancer-associated gene expression patterns in tumor samples before and after treatment. Furthermore, we used linear support vector regression to predict the cellular composition of tumor samples.
Results:
Using differential expression analysis, we identified the downregulation of CXCL14 and upregulation of CCL21, ANGPTL4, and CRABP2 genes. We also found a decreased predicted proportion of dendritic cells while the proportion of neutrophils was increased.
Conclusion:
This study provides evidence that calcium electroporation for esophageal cancer induces local transcriptional changes and possibly alters the cellular composition of the tumor microenvironment. The results are explorative, larger studies are needed to confirm and further correlate our findings with clinical outcomes.
... Only one Cxcl14 3' UTR isoform is annotated, but ReadZS analysis predicts a decrease in length of about 600 bps (Figure 4c ) (Bässler et al., 2001 ). The protein product of Chemokine (C-X-C motif) ligand 14, Cxcl14 or BRAK, is a small chemokine of length 99 residues in mouse and 111 in human, and was originally found to be highly expressed in breast and kidney (Hromas et al., 1999 ). Cxcl14 is constitutively expressed in skin and keratinocytes and is a potent leukocyte recruitment factor (Westrich et al., 2020 ) but has also more recently been observed as constitutively expressed throughout multiple brain regions where one of its functions is to regulate synaptic transmission (Banisadr et al., 2011 ). ...
Targeted low-throughput studies have previously identified subcellular RNA localization as necessary for cellular functions including polarization, and translocation. Further, these studies link localization to RNA isoform expression, especially 3’ Untranslated Region (UTR) regulation. The recent introduction of genome-wide spatial transcriptomics techniques enable the potential to test if subcellular localization is regulated in situ pervasively. In order to do this, robust statistical measures of subcellular localization and alternative poly-adenylation (APA) at single cell resolution are needed. Developing a new statistical framework called SPRAWL, we detect extensive cell-type specific subcellular RNA localization regulation in the mouse brain and to a lesser extent mouse liver. We integrated SPRAWL with a new approach to measure cell-type specific regulation of alternative 3’ UTR processing and detected examples of significant correlations between 3’ UTR length and subcellular localization. Included examples, Timp3, Slc32a1, Cxcl14, and Nxph1 have subcellular localization in the brain highly correlated with regulated 3’ UTR processing that includes use of unannotated, but highly conserved, 3’ ends. Together, SPRAWL provides a statistical framework to integrate multi-omic single-cell resolved measurements of gene-isoform pairs to prioritize an otherwise impossibly large list of candidate functional 3’ UTRs for functional prediction and study. SPRAWL predicts 3’ UTR regulation of subcellular localization may be more pervasive than currently known.
... In addition, several bioactive peptides control hormone secretion via paracrine and autocrine mechanisms in the pituitary gland (Bilezikjin & Vale, 2011). C-X-C motif chemokine ligand 14 (CXCL14) was originally isolated from human tumour cells such as BRAK (Hromas et al., 1999), BMAC (Sleeman et al., 2000) and MIP-2γ (Cao et al., 2000). CXCL14 is a unique 77 amino acid peptide that plays an important function not only in the immune system but also in the nervous and endocrine systems (Atanes et al., 2019;Nara et al., 2007;Suzuki et al., 2017Suzuki et al., , 2022Suzuki & Yamamoto, 2015, 2023Yamamoto et al., 2011Yamamoto et al., , 2020. ...
This is the first study to examine the distribution of a chemokine CXCL14‐like peptide in the pituitary and hypothalamus of an avian species, the Japanese quail (Coturnix japonica). We employed immunohistochemical techniques using a specific anti‐human CXCL14 antibody. CXCL14‐immunoreactive cells were detected in the caudal lobe of the pars distalis. CXCL14‐immunoreactive puncta were densely distributed in the external layer and sparsely distributed in the internal layer of the median eminence. CXCL14 staining was absent after pre‐absorption of the antibody with recombinant human CXCL14. All CXCL14‐immunoreactive cells corresponded to growth hormone (GH)‐producing cells in the caudal lobe. In addition, the majority of CXCL14‐immunoreactive puncta in the median eminence corresponded to somatostatin‐containing fibres. CXCL14 secreted from GH‐producing cells and somatostatin‐containing fibres may act as an inhibitor of GH release via an autocrine mechanism and neuroendocrine signalling, respectively.
... Mechanistically, CXCL14 upregulates inflammatory cytokine signaling but downregulates mTORC and OXPHOS signaling pathways, accompanied by impaired mitochondrial respiratory function. This finding is consistent with previous reports that mTOR signaling inhibition sensitizes CML LSC response to TKI. 44,45,56,57 CXCL14 is a CXC chemokine highly conserved in mammals with only two amino acids difference between mice and humans, and was initially identified in breast and kidney cells, 58 thus termed as BRAK. CXCL14 shares high amino acid sequence conservation with CXCL12 59 which is known to be important for maintaining normal hematopoiesis 60,61 and protecting CML LSCs during TKI treatment. ...
Although tyrosine kinase inhibitors are effective for treating chronic myeloid leukemia (CML), they often fail to eradicate the leukemia-initiating stem cells (LSCs), causing disease persistence and relapse. Evidence indicates that LSC persistence may be due to bone marrow (BM) niche protection. However, little is known about the underlying mechanisms. We here molecularly and functionally characterized BM niches in CML patients at diagnosis and revealed the altered niche composition and function in the CML patients. Long-term culture initiating cell (LTC-IC) assay showed that the mesenchymal stem cells from CML patients displayed an enhanced supporting capacity for normal and CML BM CD34+CD38- cells. Molecularly, RNA sequencing detected dysregulated cytokine and growth factor expression in CML patient BM cellular niches. Among them, CXCL14 was lost in the BM cellular niches in contrast to its expression in healthy BM. Restoring CXCL14 significantly inhibited CML LSC maintenance and enhanced their response to imatinib in vitro, and CML engraftment in vivo in NSG-SGM3 mice. Importantly, CXCL14 treatment dramatically inhibited CML engraftment in xenografted NSG-SGM3 mice, even to a greater degree than imatinib, and this inhibition persisted in patients with suboptimal TKI response. Mechanistically, CXCL14 upregulated inflammatory cytokine signaling but downregulated mTOR signaling and oxidative phosphorylation in CML LSCs. Together, we have discovered a suppressive role of CXCL14 in CML LSC growth. CXCL14 might offer a treatment option targeting CML LSCs.
... CXCL14 (also known as BRAK, BMAC, or Mip-2γ) is found in skeletal muscle, white adipose tissue, and brown adipose tissue, implying that it may be involved in myogenesis, adipogenesis, and metabolic regulation. CXCL14 attracts activated tissue macrophages and dendritic progenitor cells as a chemoattractant [87][88][89][90][91][92][93]. CXCL14 promotes visceral obesity and adipose tissue inflammation in animals, leading to an increase in hepatic gluconeogenesis and the development of IR [19,65,[94][95][96]. ...
... CXCL14 (also known as BRAK, BMAC, or Mip-2γ) is found in skeletal muscle, white adipose tissue, and brown adipose tissue, implying that it may be involved in myogenesis, adipogenesis, and metabolic regulation. CXCL14 attracts activated tissue macrophages and dendritic progenitor cells as a chemoattractant [87][88][89][90][91][92][93]. CXCL14 promotes visceral obesity and adipose tissue inflammation in animals, leading to an increase in hepatic gluconeogenesis and the development of IR [19,65,[94][95][96]. ...
Adipose tissue develops lipids, aberrant adipokines, chemokines, and pro-inflammatory cytokines as a consequence of the low-grade systemic inflammation that characterizes obesity. This low-grade systemic inflammation can lead to insulin resistance (IR) and metabolic complications, such as type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). Although the CXC chemokines consists of numerous regulators of inflammation, cellular function, and cellular migration, it is still unknown that how CXC chemokines and chemokine receptors contribute to the development of metabolic diseases (such as T2D and NAFLD) during obesity. In light of recent research, the objective of this review is to provide an update on the linkage between the CXC chemokine, obesity, and obesity-related metabolic diseases (T2D and NAFLD). We explore the differential migratory and immunomodulatory potential of CXC chemokines and their mechanisms of action to better understand their role in clinical and laboratory contexts. Besides that, because CXC chemokine profiling is strongly linked to leukocyte recruitment, macrophage recruitment, and immunomodulatory potential, we hypothesize that it could be used to predict the therapeutic potential for obesity and obesity-related diseases (T2D and NAFLD).
... to convey anti-inflammatory effects in collagen-induced arthritis (Xu et al., 2008). Moreover, transcripts for the angiogenesis promoting and MSC recruiting stromal cell-derived factor 1 (Cxcl12) were lower in NP cells (Takano et al., 2014), whereas transcripts encoding the cytokine Il6 with impact on inflammation, bone homeostasis, and angiogenesis; Cxcl14, acting as an angiogenesis inhibitor (Hromas et al., 1999;Shellenberger et al., 2004); and Cxcr4, encoding the receptor for Cxcl12, were higher in NP cells. This likely renders monolayer cultured adipose stromal cells preferable over NP-derived cells for cell replacement therapies. ...
Regenerative medicine aims to repair degenerate tissue through cell refurbishment with minimally invasive procedures. Adipose tissue (FAT)-derived stem or stromal cells are a convenient autologous choice for many regenerative cell therapy approaches. The intervertebral disc (IVD) is a suitable target. Comprised of an inner nucleus pulposus (NP) and an outer annulus fibrosus (AF), the degeneration of the IVD through trauma or aging presents a substantial socio-economic burden worldwide. The avascular nature of the mature NP forces cells to reside in a unique environment with increased lactate levels, conditions that pose a challenge to cell-based therapies. We assessed adipose and IVD tissue-derived stromal cells through in vitro transcriptome analysis in 2D and 3D culture and suggested that the transcription factor Glis1 and metabolite oxaloacetic acid (OAA) could provide NP cells with survival tools for the harsh niche conditions in the IVD.
Keywords: 3D culture; adipose; annulus fibrosus; intervertebral disc; nucleus pulposus; regenerative medicine; stromal cell; transcriptome analysis.
... This chemokine is expressed in gastrointestinal and respiratory tissues (Pisabarro et al. 2006;Weinstein et al. 2006). In contrast to CCL25 and CXCL14, which can be detected within the solid parenchyma of different tissues and epithelial barriers, CXCL17 expression is only limited to the epithelial barriers responsible for covering various secretory conduct and hollow organ lumens (Vicari et al. 1997;Hromas et al. 1999;Maerki et al. 2009). The gene comprises four exons involved in coding a propeptide with 119 amino acids (Xiao et al. 2021). ...
Chemokines are immune system mediators that mediate various activities and play a role in the pathogenesis of several cancers. Among these chemokines, C-X-C motif chemokine 17 (CXCL-17) is a relatively novel molecule produced along the airway epithelium in physiological and pathological conditions, and evidence shows that it plays a homeostatic role in most cases. CXCL17 has a protective role in some cancers and a pathological role in others, such as liver and lung cancer. This chemokine, along with its possible receptor termed G protein-coupled receptor 35 (GPR35) or CXCR8, are involved in recruiting myeloid cells, regulating angiogenesis, defending against pathogenic microorganisms, and numerous other mechanisms. Considering the few studies that have been performed on the dual role of CXCL17 in human malignancies, this review has investigated the possible pro-tumor and anti-tumor roles of this chemokine, as well as future treatment options in cancer therapy.Graphical Abstract
... Epithelial-like cells further separated into three distinct sub-clusters on the basis of genes identified by differential gene expression analysis (Supplementary Table 2), reflecting their putative role in the malignancy of RMC. Specifically, one sub-cluster (CXCL14+ EPCAM+ cells) exclusively contained cells expressing the breast and kidneyexpressed chemokine CXCL14 (third top-scoring differentially expressed gene, as ranked by adjusted p-value = 1.566e-9) that is reduced or absent from most cancer cells and used to distinguish normal tissue (40,41). This finding, together with the observation that the CXCL14+ EPCAM+ cells retained expression of SMARCB1 (27.6% of cells), strongly suggests that the CXCL14+ EPCAM+ cluster contained either untransformed epithelial cells or those in the early stages of transformation ( Figure 2B). ...
Renal medullary carcinoma (RMC) is a highly aggressive disease associated with sickle hemoglobinopathies and universal loss of the tumor suppressor gene SMARCB1. RMC has a relatively low rate of incidence compared with other renal cell carcinomas (RCCs) that has hitherto made molecular profiling difficult. To probe this rare disease in detail we performed an in-depth characterization of the RMC tumor microenvironment using a combination of genomic, metabolic and single-cell RNA-sequencing experiments on tissue from a representative untreated RMC patient, complemented by retrospective analyses of archival tissue and existing published data. Our study of the tumor identifies a heterogenous population of malignant cell states originating from the thick ascending limb of the Loop of Henle within the renal medulla. Transformed RMC cells displayed the hallmarks of increased resistance to cell death by ferroptosis and proteotoxic stress driven by MYC-induced proliferative signals. Specifically, genomic characterization of RMC tumors provides substantiating evidence for the recently proposed dependence of SMARCB1-difficient cancers on proteostasis modulated by an intact CDKN2A-p53 pathway. We also provide evidence that increased cystine-mTORC-GPX4 signaling plays a role in protecting transformed RMC cells against ferroptosis. We further propose that RMC has an immune landscape comparable to that of untreated RCCs, including heterogenous expression of the immune ligand CD70 within a sub-population of tumor cells. The latter could provide an immune-modulatory role that serves as a viable candidate for therapeutic targeting.
... The increased expression of the CXC motif chemokine 14 (CXCL14, BRAK, or MIP-2G) in PXA was a striking exception. CXCL14 is a chemokine implicated in both homeostatic immune functions, particularly in squamous epithelium, and host-tumor immune interactions (29,41). In several cancers CXCL14 expression is altered, with increased expression reported in tumor cells in papillary thyroid carcinoma (42) and decreased tumor cell expression associated with disease progression in human papillomavirus (HPV)-associated cervical and head and neck carcinoma (30,31). ...
Purpose:
The immunosuppressive tumor microenvironment present in the majority of diffuse glioma limits therapeutic response to immunotherapy. As the determinants of the glioma-associated immune response are relatively poorly understood, the study of glioma with more robust tumor-associated immune responses may be particularly useful to identify novel immunomodulatory factors that can promote T cell effector function in glioma.
Experimental design:
We used multiplex immune-profiling, proteomic profiling, and gene expression analysis to define the tumor-associated immune response in two molecular subtypes of glioma and identify factors that may modulate this response. We then used patient-derived glioma cultures and an immunocompetent murine model for malignant glioma to analyze the ability of tumor-intrinsic factors to promote a CD8+ T cell response.
Results:
As compared with IDH-mutant astrocytoma, MAPK-activated pleomorphic xanthoastrocytoma (PXA) harbored increased numbers of activated cytotoxic CD8+ T cells and Iba1+ microglia/macrophages, increased MHC class I expression, enrichment of genes associated with antigen presentation and processing, and increased tumor cell secretion of the chemokine CXCL14. CXCL14 promoted activated CD8+ T cell chemotaxis in vitro, recruited tumor-infiltrating CD8+ T cells in vivo, and prolonged overall survival in a cytotoxic T cell-dependent manner. The immunomodulatory molecule B7-H3 was also highly expressed in PXA.
Conclusions:
We identify the MAPK-activated lower grade astrocytoma PXA, as having an immune-rich tumor microenvironment and suggest this tumor may be particularly vulnerable to immunotherapeutic modulation. We also identify CXCL14 as an important determinant of the glioma-associated immune microenvironment, sufficient to promote an anti-tumor CD8+ T cell response.
... The copyright holder for this preprint this version posted April 28, 2022. ; https://doi.org/10.1101/2022.04.28.489873 doi: bioRxiv preprint contained cells expressing the breast and kidney-expressed chemokine CXCL14 (third top-scoring differentially expressed gene, as ranked by adjusted p-value = 1.566e-9) that is reduced or absent from most cancer cells and used to distinguish normal tissue (40) (41). This finding, together with the observation that the CXCL14+ EPCAM+ cells retained expression of SMARCB1 (27.6 % of cells), strongly suggests that the CXCL14+ EPCAM+ cluster contained either untransformed epithelial cells or those in the early stages of transformation ( Figure 2B). ...
Renal medullary carcinoma (RMC) is a highly aggressive disease associated with sickle hemoglobinopathies and universal loss of the tumor suppressor gene SMARCB1. RMC has a relatively low rate of incidence compared with other renal cell carcinomas (RCCs) that has hitherto made molecular profiling difficult. To probe this rare disease in detail we performed an in-depth characterization of the RMC tumor microenvironment using a combination of genomic, metabolic and single-cell RNA-sequencing experiments on tissue from a representative untreated RMC patient, complemented by retrospective analyses of archival tissue and existing published data. Our study of the tumor identifies a heterogenous population of malignant cell states originating from the thick ascending limb of the Loop of Henle within the renal medulla, displaying the hallmarks of increased resistance to cell death by ferroptosis and proteotoxic stress driven by MYC-induced proliferative signals. Specifically, genomic characterization of RMC tumors provides substantiating evidence for the recently proposed dependence of SMARCB1-difficient cancers on an intact CDKN2A-p53 pathway and we suggest increased cystine-mTORC-GPX4 signaling also plays a role within transformed RMC cells. We further propose that RMC has an immune landscape comparable to that of untreated RCCs, including heterogenous expression of the immune ligand CD70 within a sub-population of tumor cells, which could provide an immune-modulatory role that serves as a viable candidate for therapeutic targeting.
... 17 Vgl. Hromas et al. (1999). 18 Vgl. ...
... Indeed, CXCL14 was only first described in 1999, and remains one of the least understood chemokines. 6 Although CXCL14 shares a degree of structural homology with other chemokines, namely CXCL1, CXCL2, and CXCL8, it is unique since it does not bind to their cognate receptor, CXCR2. As a consequence, CXCL14 has been termed an orphan chemokine, given the ongoing debate regarding its native receptor. ...
... 7 CXCL14 was initially discovered in the breast and kidney, so it is also named breast and kidney-expressed chemokine (BRAK). 8 Unlike other chemokines induced by infection, CXCL14 is constitutively produced by epithelial cells and displays antimicrobial activity. 9,10 It can also be expressed by monocyte-derived cells and macrophages and plays an immune surveillance role by chemoattracting those cells. ...
Porcine reproductive and respiratory syndrome (PRRS) is the most economically important infectious disease of pigs worldwide. Our previous study revealed that Tongcheng (TC) pigs display higher resistance to PRRS than Largewhite (LW) pigs, but the genetic mechanism remains unknown. Here, we first confirmed that CXCL14 was downregulated in lungs and porcine alveolar macrophages (PAMs) responding to PRRS virus (PRRSV) infection, but the decline in LW pigs was more obvious than that in TC pigs. Then, we found that the overexpression of CXCL14 activated type‐I interferon (IFN‐I) signaling by upregulating interferon beta (IFNB), which plays a major role in the antiviral effect. To further decipher the mechanism underlying its differential expression, we characterized the core promoter of CXCL14 as being located from −145 to 276 bp of the transcription start site (TSS) and identified two main haplotypes that displayed significant differential transcriptional activities. We further identified two coupled point mutations that altered the binding status of CEBPB and were responsible for the differential expression in TC and LW pigs. The regulatory effect of CEBPB on CXCL14 was further confirmed by RNA interference (RNAi) and chromatin immunoprecipitation (ChIP), providing crucial clues for deciphering the mechanism of CXCL14 downregulation in unusual conditions. The present study revealed the potential antiviral effect of CXCL14, occurring via activation of interferon signaling, and suggested that CXCL14 contributes to the PRRS resistance of TC pigs.
... y-axis, sensitivity; x-axis, 1 − specificity extracellular space. A gene related with extracellular space, CXCL14, was validated to show significantly higher expression in adenocarcinoma with MPP and was thus identified as a possible biomarker of this subtype.CXCL14, also called BRAK, was first identified to be expressed in the breast and kidney, and shown to be ubiquitously expressed in almost all cell types, especially epithelial cells, but not in many tumor cell lines in vitro.22,23 In colorectal, breast, papillary thyroid cancer, and osteosarcoma, high expression of CXCL14 reportedly associated with metastasis and poor prognosis.[24][25][26][27] ...
Lung adenocarcinoma with micropapillary pattern (MPP) has an aggressive malignant behavior. Limited resection should be avoided because of its high recurrence rate. If adenocarcinoma with MPP is diagnosed preoperatively, the selection of proper treatment is possible. To explore a preoperative biomarker for diagnosing MPP, we here conducted RNA sequencing analysis of 25 clinical samples as the training set, including 6 MPP, 16 other adenocarcinoma subtypes and 3 normal lung tissues. Unsupervised hierarchical clustering analysis suggested a presence of subgroup with MPP showing different gene expression phenotype. We extracted differentially expressed genes with high expression levels in MPP samples, and chose VSIG1, CXCL14 and BAMBI as candidate biomarkers for MPP. RT‐qPCR analysis confirmed a significantly higher expression of VSIG1 (P=0.03) and CXCL14 (P=0.02) in MPP than others. In validation set of 4 MPP and 4 non‐MPP samples, CXCL14 expression was validated to be significantly higher in MPP than in non‐MPP (P=0.04). Comparing a total of 10 MPP and 20 non‐MPP samples, the AUC of CXCL14 to distinguish MPP from others was 0.89. The threshold value was 0.0116 corresponding to sensitivity 80% and specificity 90%. In immunostaining of CXCL14, the staining score was significantly higher in MPP cases than others, where not only MPP component but also other components showed heterogeneous staining in adenocarcinoma tissues with MPP. Moreover, higher staining score of CXCL14 significantly associated with poorer prognosis, in all patients (P=0.01) or within cases at stage I‐III (P=0.01).In summary, we identified CXCL14 as a possible diagnostic biomarker of MPP.
... CXCL14 is a protein-coding gene, which belongs to the cytokine gene family and encodes secretory proteins that are involved in immune regulation and inflammatory processes. It was also known as breast and kidney-expressed chemokine (BRAK), which was a chemokines for expressed in the breast and kidney, and it can inhibit angiogenesis [19] . The protein encoded by this gene was structurally related to the CXC (cys-x-cys) subfamily of cytokine, showing chemotactic activity to monocytes, which was also an enhancer and activator to dendritic cells, participating in homing of these cells [20] , and stimulating the migration of activated NK cells [21] . ...
Objective: This study applied the public genetic databases high-throughput gene expression omnibus (GEO) database to compare the difference of gene screening between the repeated implantation failure (RIF) patients and women with normal endometrium. This study aims to provide additional information for the diagnosis and treatment in RIF patients through the gene set enrichment analysis and the construction of protein to protein interactions (PPIs) network.
Method: The human endometrial microarray data of RIF and normal control group were obtained from the GEO database provided by the National Center for Biotechnology Information (NCBI). The analysis and the review of differential gene screening, gene ontology (GO) pathway analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and PPIs network construction were carried out.
Result: 273 genes with differential expression, 87 up-regulated and 186 down-regulated genes, were obtained through differential gene analysis. 50 genes with the most significant differential expression fold change were screened for subsequent analysis. KEGG results indicated that the top three related pathways were cancer pathway, MAPK signaling pathway, and homologous recombination pathway when the relevant pathways were sequenced according to the correlation size. GO analysis showed that differentially expressed genes were involved in protein phosphorylation, complement activation, and other biological processes. PPIs analysis demonstrated that targeted genes show high correlation to the endometrial receptivity, including PAEP, CXCL14, HOXB3, CD55, and VEGFA, all were down-regulated in RIF endometrial tissues compared to the control group, and these genes also influenced and regulated each other.
Conclusion: Through public databases and bioinformatics, several factors in endometrial receptivity that affect RIF directly and indirectly were found. In particular, the immune and angiogenesis factors stood out the most. The different genes which regulate the immune response and angiogenesis response may become new targeted treatment for RIF.
... CXCL14 is a relatively new CXC chemokine constitutively expressed in the breast, kidney, and other epithelial tissues [12,13]. Although the molecular mechanism governing CXCL14-mediated functions are unclear, several evidences indicate a role of CXCL14 in antitumor immunity and inflammatory response [14,15]. ...
CXCL14 is a relatively novel chemokine with a wide spectrum of biological activities. The present study was designed to investigate whether CXCL14 overexpression attenuates sepsis-associated acute kidney injury (AKI) in mice. Sepsis model has been established by cecal ligation and puncture (CLP). CLP induced AKI in mice as assessed by increased renal neutrophil gelatinase-associated lipocalin (NGAL) expression and serum creatinine levels. We found that renal CXCL14 expression in the kidney was significantly decreased at 12 hours after CLP. Correlation analysis demonstrated a negative association between renal CXCL14 expression and AKI markers including serum creatinine and renal NGAL. Moreover, CXCL14 overexpression reduced cytokine (TNF-α, IL-6, and IL-1β) production and NGAL expression in the kidney and decreased serum creatinine levels. In vivo and in vitro experiments found that CXCL14 overexpression inhibited M1 macrophage polarization but increased M2 polarization. Together, these results suggest that CXCL14 overexpression attenuates sepsis-associated AKI probably through the downregulation of macrophages-derived cytokine production. However, further studies are required to elucidate the underlying mechanism.
... Generally, ELR + chemokines are potent promoters of angiogenesis, whereas ELRchemokines are potent inhibitors of angiogenesis [29]. CXCL14 is a member of the ELRchemokines, independently isolated as BRAK [14], BMAC [27], or MIP-2 [5] from human tumor cells. A transwell migration assay demonstrated that CXCL14 significantly stimulates the migration of human blood monocytes [19] and natural killer cells [28]. ...
The distribution pattern of chemokine CXCL14-immunoreactive cells was examined by immunohistochemistry in the pituitary of the gecko Hemidactylus platyurus. Immunoreactive cells were observed in the pars intermedia and pars distalis of the pituitary, but not in the pars nervosa. All α-melanocyte-stimulating hormone (αMSH)-producing cells were immunoreactive for CXCL14 in the pars intermedia. The CXCL14-immunoreactive cells corresponded to prolactin (PRL)-producing cells but not to other adenohypophyseal-hormone-producing cells in the pars distalis. CXCL14 secreted from αMSH-producing cells and PRL-producing cells may regulate insulin release from β cells in the pancreatic islets as well as glucose uptake in the muscle cells together with αMSH and/or PRL. In addition, secreted CXCL14 with αMSH and/or PRL may act as a bioactive factor regulating hormone release in the adenohypophyseal cells of the reptilian pars distalis.
... 7 As a member of the CXC chemokine family, it was first identified in breast and kidney cells and was shown to be constitutively and widely expressed in normal tissues. 8 An in situ mRNA hybridization study suggested that the expression of CXCL14 mRNA was absent in head and neck squamous cell carcinoma and cervical squamous cell carcinoma. 9 However, publications have emerged that offer contradictory findings regarding CXCL14 expression in cancer. ...
Introduction
CXCL14 was a significantly under-expressed mRNA in hepatocellular carcinoma tissues according to our microarray analysis, as well as head and neck squamous cell carcinoma and cervical squamous cell carcinoma. CXCL14 was considered a tumor suppressor in some studies; however, its role in HBV infection has not been identified.
Methods
CXCL14 mRNA expression was quantified from 20 male HCC patients, and the fold change in cancer tissues was calculated by comparisons with normal adjacent tissues. Overall, 212 patients with chronic HBV infection and 180 HBV-free controls were recruited to investigate the association between CXCL14 polymorphisms and HBV progression as well as liver function parameters. Serum CXCL14 levels were determined by enzyme-linked immunosorbent assay (ELISA), and comparisons were made between different HBV status and different CXCL14 genotypes.
Results
The mRNA expression of CXCL14 was 0.33-fold in HCC tissues when compared with adjacent tissues. The frequencies of rs2237062 and rs2547, but not rs2237061, were significantly different between patients with mild hepatitis and moderate-to-severe hepatitis. Moreover, rs2237062 and rs2547 polymorphisms correlated with impaired liver function parameters. ELISA results suggested that HBV-free controls had the highest level of CXCL14, while mild hepatitis patients had low levels, and patients with moderate-to-severe hepatitis had the lowest level. GA+AA genotypes of rs2547 were associated with reduced levels of serum CXCL14 because it introduced a stop codon at residue 109.
Conclusion
CXCL14 was significantly suppressed in HBV-related HCC tissues, and its polymorphisms were linked with advanced stage chronic HBV infection and impaired liver function.
... Chemokines are a superfamily of small chemotactic cytokines, Chemokine (C-X-C motif) ligand 14 (CXCL14) is a member of the BRAK superfamily [15] Previous studies have reported the CXC chemokine superfamily plays an important role in inflammatory, autoimmune and tumorigenic functions [16,17]. Normal human epithelial cells constitutively express CXCL14, its expression is frequently reduced in cervical, prostate, and oral cancers [18,19]. ...
To identify the mechanism and functions of IRX1 in heart failure (HF) and provide evidence for new therapies. Bioinformatic analysis was performed to select target genes in HF cells compared to normal groups. Experimental rats were treated in a controllable manner to explore how IRX1 methylation accounted for this disease in vivo. Cardiac ultrasonic and morphologic examinations were conducted to test the mouse heart and evaluate the degree of cardiac impairment at in the level of organization. GSEA analysis revealed the relative enrichment of functions. Immunofluorescent assays, western blotting and qRT-PCR were used to determine the DNA methylation and expression levels. IRX1 was hypermethylated in heart failure and identified as a target gene by bioinformatic analysis. Transverse aortic constriction (TAC) induced heart failure in rats, while 5-aza-2ʹ-deoxycytidine (5-Aza) alleviated heart failure in rats according to medical cardiac indexes. Western blotting and qRT-PCR revealed that a conspicuous difference in the expression of IRX1 and CXCL14 between HF and normal cardiac cells. As a result of gene methylation, left ventricular hypertrophy and cardiac fibrosis is usually accompanied by heart failure. Moreover, is the results implied that the demethylation of IRX1 improves heart failure in vivo and in vitro. IRX1 methylation induced damaged cardiac function and even heart failure, which has important implications for HF treatment and diagnosis.
Simple Summary
Pancreatic ductal adenocarcinoma (PDAC) has a dismal 5-year survival rate of only 11.6%, partially due to limited therapeutic options. Immunotherapy-based approaches, such as immune checkpoint inhibitors, have proven ineffective, in part due to the inability of cytotoxic, effector immune cells to sufficiently infiltrate tumors. Thus, understanding how the PDAC tumor microenvironment (TME) regulates the accumulation of immune cells is critical to improving immunotherapy-based approaches.
Abstract
Chemokines are small molecules that function as chemotactic factors which regulate the migration, infiltration, and accumulation of immune cells. Here, we comprehensively assess the structural and functional role of chemokines, examine the effects of chemokines that are present in the pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME), specifically those produced by cancer cells and stromal components, and evaluate their impact on immune cell trafficking, both in promoting and suppressing anti-tumor responses. We further explore the impact of chemokines on patient outcomes in PDAC and their role in the context of immunotherapy treatments, and review clinical trials that have targeted chemokine receptors and ligands in the treatment of PDAC. Lastly, we highlight potential strategies that can be utilized to harness chemokines in order to increase cytotoxic immune cell infiltration and the anti-tumor effects of immunotherapy.
Background
CXCL14 is a member of CXC chemokine family, constitutively expressed in various normal tissues unlike many other chemokines. Other than the capacity to recruit natural killer cells, macrophages, and dendritic cells, CXCL14 suppresses CXCL12‐CXCR4 interactions by inducing CXCR4 internalization. Thus, CXCL14 can both promote and hinder immune responses. Psoriasis is a chronic skin inflammatory disorder in which various chemokines play an important role.
Methods
To investigate possible roles of CXCL14 in psoriasis, we examined CXCL14 expression in lesional skin by immunohistochemistry and measured serum CXCL14 levels in psoriasis. We also assessed the effect of ultraviolet irradiation, one of the main therapies for psoriasis, on CXCL14 expression by HaCaT cells.
Results
CXCL14 expression was decreased in epidermal keratinocytes in lesional skin and serum CXCL14 levels were negatively correlated with Psoriasis Area and Severity Index scores in psoriasis patients. Serum CXCL14 levels were increased in nbUVB‐treated psoriasis patients and UVB irradiation induced CXCL14 mRNA expression from HaCaT cells.
Conclusion
Our results suggest that decreased CXCL14 expression may contribute to the exacerbation of psoriasis and that the amplification of CXCL14 can be a therapeutic option for psoriasis. One of the mechanisms of the efficacy of nbUVB therapy in psoriasis may be the upregulation of CXCL14.
This study examines chemokine CXCL14‐like peptide distribution in the Japanese quail (Coturnix japonica) pancreas using a specific anti‐human CXCL14 antibody. CXCL14‐immunoreactive cells were observed in the pancreatic islet peripheral region. The staining was abolished after pre‐absorbing the antibody with recombinant human CXCL14. CXCL14‐immunoreactive cells were immuno‐positive for somatostatin, but not glucagon and insulin. CXCL14 secreted from somatostatin‐producing cells might participate in insulin secretion modulation together with somatostatin. In addition, CXCL14 might participate in glucose homeostasis in co‐operation with somatostatin and growth hormone.
Adipose tissue macrophage (ATM) has been appreciated for its critical contribution to obesity-associated metabolic diseases in recent years. Here, we discuss the regulation of ATM on both metabolic homeostatsis and dysfunction. In particular, the macrophage polarization and recruitment as well as the crosstalk between ATM and adipocyte in thermogenesis, obesity, insulin resistance and adipose tissue fibrosis have been reviewed. A better understanding of how ATM regulates adipose tissue remodeling may provide novel therapeutic strategies against obesity and associated metabolic diseases.
Abstract
Background and purpose: Asthma is a chronic inflammatory disorder of the airways caused by
a combination of complex environmental and genetic interactions. There is an incomplete understanding
of this mechanism which affect both severity of the disease and how it responds to treatment. Different
gene expressions are reported in patients with asthma and healthy controls.
Materials and methods: In this study, a common list of different genes expressed (DEG) was
identified using bioinformatics methods. Three studies from microarray data that met the study’s
inclusion criteria were selected. These studies included 268 samples, consisting of 167 patients and 101
healthy people. These studies were analyzed, and then a meta-analysis was performed.
Results: Common genes that led to significant decrease or increase in gene expressions were
identified and their biological, molecular, and cellular pathways were examined. In general, it was found
that this set of genes can be involved in asthma and some pathways affecting the function of disease.
Conclusion: According to current findings, examining the objectives of efficacy and functional
analysis of new genes effective in asthma and their protein products, and also investigating the role of
interactions in asthma could help in taking appropriate treatment strategies to control asthma
complications and injuries.
Lung cancer persists to contribute to one-quarter of cancer-associated deaths. Among the different histologies, non-small cell lung cancer (NSCLC) alone accounts for 85% of the cases. The development of therapies involving immune checkpoint inhibitors and angiogenesis inhibitors has increased patients' survival probability and reduced mortality rates. Developing targeted therapies against essential genetic alterations also translates to better treatment strategies. But the benefits still seem farfetched due to the development of drug resistance and refractory tumors. In this review, we have highlighted the interplay of different tumor microenvironment components, essentially discussing the chemokine families (CC, CXC, C, and CX3C) that regulate the tumor biology in NSCLC and promote tumor growth, metastasis, and associated heterogeneity. The development of therapeutics and prognostic markers is a complex and multipronged approach. However, some essential chemokines can act as critical players for being considered potential prognostic markers and therapeutic targets.
Background
Effective biomarkers for early diagnosis of lung cancer are needed. Previous studies have indicated positive associations between abnormal circulating cytokines and the etiology of lung cancer.
Methods
Blood samples were obtained from 286 patients with pretreatment lung cancer and 80 healthy volunteers. Circulating cytokine levels were detected with a Luminex assay and enzyme-linked immunosorbent assay (ELISA). Urine samples were obtained from 284 patients and 122 healthy volunteers. CXC chemokine ligand 14 (CXCL14) expression in tumors and nontumor regions of lung tissues from 133 lung cancer cases was detected by immunohistochemical (IHC) staining and immunofluorescence (IF) staining of formalin fixed paraffin-embedded (FFPE) tissues.
Results
Compared with healthy volunteers, a 65.7-fold increase was observed in the level of CXCL14 in the plasma of lung cancer patients, and a 1.7-fold increase was observed in the level of CXCL14 in the urine of lung cancer patients, achieving a 0.9464 AUC (area under the curve) value and a 0.6476 AUC value for differentiating between lung cancer patients and healthy volunteers, respectively. Stromal CXCL14 expression was significantly associated with advanced pathologic stage (P<0.001), pathologic N stage (P<0.001), and recurrence and metastasis (P=0.014). Moreover, multivariate analysis suggested stromal CXCL14 expression as an independent predictor of DFS and OS.
Conclusions
Our study demonstrates that CXCL14 might serve as a potential diagnostic and prognostic biomarker in patients with lung cancer.
Impact
CXCL14 might serve as a potential diagnostic and prognostic biomarker in patients with lung cancer.
Aims: To evaluate BRAK and APRIL in serum samples from healthy patients and an ovarian tumor group and analyze their effective value as biomarkers. Materials & methods: BRAK and APRIL were measured in 197 serum samples including 34 healthy controls, 48 patients with benign ovarian cysts and 115 patients with ovarian cancer, and the best statistical cutoff values were calculated. Then, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value for selected cutoff points were assessed. Results: The healthy control group had statistically significant higher BRAK and lower APRIL than the ovarian tumor group. BRAK was excellent for differentiating healthy patients from patients with ovarian tumors, showing area under the receiver operating characteristic curve 0.983, 98.16% sensitivity and 100% specificity. When BRAK was combined with APRIL and CA-125, it also played a role in distinguishing benign cysts from malignancies with area under the curve 0.864, 81.74% sensitivity and 79.17% specificity. Conclusions: BRAK and APRIL are good candidates for ovarian tumor biomarkers.
This study provided the first analysis of the distribution of a CXCL14-like chemokine in the Japanese eel (Anguilla japonica) pituitary using immunohistochemical techniques. CXCL14-immnoreactive cells were observed in the rostral part of the pars distalis (RPD) and the pars intermedia (PI). The CXCL14-immunoreactive cells were found to correspond to adrenocorticotropic hormone (ACTH)-producing cells in the RPD and α-melanocyte-stimulating hormone (αMSH)-producing cells in the PI. Therefore, the CXCL14 secreted from the αMSH-producing cells and ACTH-producing cells in the pituitary may participate in the modulation of insulin secretion, as well as energy metabolism, together with αMSH and/or ACTH via endocrine mechanisms.
Head and neck squamous cell carcinomas (HNSCCs) are aggressive diseases with a dismal patient prognosis. Despite significant advances in treatment modalities, the five-year survival rate in patients with HNSCC has improved marginally and therefore warrants a comprehensive understanding of the HNSCC biology. Alterations in the cellular and non-cellular components of the HNSCC tumor micro-environment (TME) play a critical role in regulating many hallmarks of cancer development including evasion of apoptosis, activation of invasion, metastasis, angiogenesis, response to therapy, immune escape mechanisms, deregulation of energetics, and therefore the development of an overall aggressive HNSCC phenotype. Cytokines and chemokines are small secretory proteins produced by neoplastic or stromal cells, controlling complex and dynamic cell–cell interactions in the TME to regulate many cancer hallmarks. This review summarizes the current understanding of the complex cytokine/chemokine networks in the HNSCC TME, their role in activating diverse signaling pathways and promoting tumor progression, metastasis, and therapeutic resistance development.
Background
Teleost scale not only provides a protective layer resisting penetration and pathogens but also participate in coloration. It is interesting to study the mechanism of teleost scale formation. Furthermore, whether there existed consensus genes between scale coloration and skin coloration has not been examined yet.
Methods and results
We analyzed the transcriptome profiles of red scale, white scale, red skin, and white skin of common carp (Cyprinus carpio). Pair-wise comparison identified 3391 differentially expressed genes (DEGs) between scale and skin, respectively. The 1765 up-regulated genes (UEGs) in scale, as the down-regulated genes in skin, preferred mineralization and other scale development-related processes. The 1626 skin UEGs were enriched in the morphogenesis of skin and appendages. We also identified 195 UEGs in white scale and 223 UEGs in red scale. The white scale UEGs primarily participated in regulation of growth and cell migration. The UEGs in red scale preferred pigment cell differentiation and retinoid metabolic process. A total of 22 DEGs had consensus expression patterns in skin and scale of the same coloration. The expression levels of these DEGs clearly grouped skin and scale of the same coloration together with principle component analysis and correlation analysis. Eleven consensus DEGs were homologous to the orthologs of Poropuntius huangchuchieni, 82% of which were under strong purifying selection. Eight processes including lipid storage and lipid catabolism were shared in both scale pigmentation and skin pigmentation.
Conclusions
We identified consensus DEGs and biological processes in scale and skin pigmentation. Our transcriptome analysis will contribute to further elucidation of mechanisms of teleost scale formation and coloration.
Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in reproductive-age women. Reduced progesterone levels are associated with luteal phase deficiency in women with PCOS. The levels of C-X-C motif chemokine ligand-14 (CXCL14) were previously reported to be decreased in human-luteinized granulosa (hGL) cells derived from PCOS patients. However, the function of CXCL14 in hGL cells and whether CXCL14 affects the synthesis of progesterone in hGL cells remain unclear. In the present study, the levels of CXCL14 were reduced in follicular fluid and hGL cells in PCOS patients, accompanied by decreased progesterone levels in follicular fluid and decreased steroidogenic acute regulatory (STAR) expression in hGL cells. CXCL14 administration partially reversed the low progesterone production and STAR expression in hGL cells obtained from PCOS patients. In primary hGL cells, CXCL14 upregulated STAR expression and progesterone production. CXCL14 activated the phosphorylation of cyclic adenosine monophosphate response element-binding protein (CREB) and CREB inhibitor attenuated the modulation of StAR expression by CXCL14. P38 and Jun N-terminal kinase (JNK) pathways were also activated by CXCL14 and inhibition of p38 and JNK attenuated the increase of phosphorylation of CREB, STAR expression and progesterone production caused by CXCL14. Our findings revealed the novel role of CXCL14 in upregulation of STAR expression and progesterone synthesis through CREB phosphorylation via activation of p38 and JNK pathways in hGL cells. This is likely contributing to the dysfunction in steroidogenesis in granulosa cells from PCOS patients.
Recent studies have proposed that the chemokine CXCL14 not only has a chemotactic activity, but also functions as a neuromodulator and/or neurotransmitter. In this study, we investigated the distribution of CXCL14 immunoreactive structures in the rat spinal cord and clarified the association of these structures with somatostatin, glutamic acid decarboxylase (GAD; a marker for GABAergic neurons), and neuropeptide Y (NPY). CXCL14 immunoreactive fibers and puncta were observed in lamina II, which modulates somatosensation including nociception, and the lateral spinal nucleus of the spinal dorsal horn at cervical, thoracic, and lumber spinal cord levels. These CXCL14 immunoreactive structures were also immuno-positive for somatostatin, but were immuno-negative for GAD and NPY. In the cervical lateral spinal nucleus, CXCL14 immunoreactive puncta, which were also immuno-positive for somatostatin, existed along the proximal dendrites of some of GABAergic neurons. Together, these results suggest that CXCL14 contributes to the modulation of somatosensation in concert with somatostatin. Neurons targeted by the CXCL14 fiber system include GABAergic neurons located in the lateral spinal nucleus suggesting that CXCL14 with somatostatin can influence the GABAergic neuron function.
Objective
This study aimed to determine the expression of chemokine (C-X-C motif) ligand 14 (CXCL14) in pulpal and periodontal cells in vivo and in vitro, and investigate function of CXCL14 and its underlying mechanism in the proliferation and osteogenic differentiation of human periodontal ligament (hPDL) cells.
Methods
To determine the expression level of CXCL14 in adult rat oral tissues and in hPDL cells after application of biophysical forces, RT-PCR, western blot, and histological analyses were performed. The role of CXCL14 in proliferation and osteogenic differentiation of PDL cells was evaluated by measuring dehydrogenase activity and Alizarin red S staining.
Results
Strong immunoreactivity against CXCL14 was observed in the PDL tissues and pulpal cells of rat molar, and attenuated apparently by orthodontic biophysical forces. As seen in rat molar, highly expressed CXCL14 was observed in human dental pulp and hPDL cells, and attenuated obviously by biophysical tensile force. CXCL14 expression in hPDL cells was increased in incubation time-dependent manner. Proliferation of hPDL cells was inhibited dramatically by small interfering (si) RNA against CXCL14. Furthermore, dexamethasone-induced osteogenic mineralization was inhibited by recombinant human (rh) CXCL14, and augmented by CXCL14 siRNA. rhCXCL14 increased transforming growth factor-beta1 (TGF- β1) in hPDL cells. Inhibition of the cell proliferation and osteogenic differentiation of hPDL cells by CXCL14 siRNA and rhCXCL14 were restored by rhTGF-β1 and SB431542, respectively.
Conclusion
These results suggest that CXCL14 may play roles as a growth factor and a negative regulator of osteogenic differentiation by increasing TGF-β1 expression in hPDL cells.
C-X-C motif chemokine 17 (CXCL-17) is a novel chemokine that plays a functional role maintaining homeostasis at distinct mucosal barriers, including regulation of myeloid-cell recruitment, angiogenesis, and control of microorganisms. Particularly, CXCL17 is produced along the epithelium of the airways both at steady state and under inflammatory conditions. While increased CXCL17 expression is associated with disease progression in pulmonary fibrosis, asthma, and lung/hepatic cancer, it is thought to play a protective role in pancreatic cancer, autoimmune encephalomyelitis and viral infections. Thus, there is emerging evidence pointing to both a harmful and protective role for CXCL17 in human health and disease, with therapeutic potential for translational applications. In this review, we provide an overview of the discovery, characteristics and functions of CXCL17 emphasizing its clinical potential in respiratory disorders.
Although chemokines mainly function to activate leukocytes and to direct their migration, novel evidence indicates non-immune functions for chemokines within the nervous and endocrine systems. These include development of the nervous system, neuromodulation, neuroendocrine regulation and direct neurotransmitter-like actions. In order to clarify a potential role for chemokines and their receptors in the stress response of fish, we studied changes in the expression patterns of CXC ligands and their receptors in the stress axis organs of carp, during a restraint stress procedure.
We showed that stress down-regulated the gene expression of CXCL9-11 (CXCb1 and CXCb2) in stress axis organs and up-regulated expression of CXCR4 chemokine receptor in NPO and pituitary. Moreover, upon stress, reduced gene expression of CXCL12a and CXCL14 was observed in the head kidney.
Our results imply that in teleost fish, CXC chemokines and their receptors are involved in neuroendocrine regulation. The active regulation of their expression in stress axis organs during periods of restraint indicates a significant role in the stress response.
The distribution and nature of CXCL14-immunoreactive nerve fibers in salivary glands, especially the parotid gland was immunohistochemically investigated. Furthermore, the origin of parotid CXCL14-immunoreactive nerve fibers was determined by retrograde tracing experiments. CXCL14-immunoreactive nerve fibers were localized in the parotid, submandibular, and sublingual glands, particularly in the parotid gland. Double staining using identical sections revealed that a subpopulation of cells neuropeptide Y (NPY)-containing fibers was immunopositive for CXCL14 in the parotid gland. In the peripheral regions of acinar cells, CXCL14-immunoreactive fibers tended to coexist with NPY; however, perivascular NPY-immunoreactive fibers tended to be immunonegative for CXCL14. Parotid CXCL14-immunoreactive fibers were immunopositive for tyrosine hydroxylase (TH) but immunonegative for choline acetyltransferase and vasoactive intestinal peptide (VIP). After injection of horseradish peroxidase-labeled wheat germ agglutinin (WGA-HRP) in the parotid gland, retrogradely labeled neurons were seen in the superior cervical ganglion (SCG) and otic ganglion. Some of the WGA-immunoreactive somata in the SCG were immunopositive for CXCL14; however, no doubly-labeled somata were noted in the otic ganglion. These results indicate that CXCL14-immunoreactive nerve fibers originate in the SCG, and are sympathetic in nature. The coexistence of CXCL14 with NPY/TH suggests that CXCL14 may be associated with NPY/TH functions as a neuromodulatory chemokine in the parotid gland. The localization of CXCL14 nerve fibers around the acinar cells of the parotid gland indicates its involvement in acinar cell function, but not vasoconstriction.
Breast cancer (BrCa) is the malignant tumor that most seriously threatens female health; however, the molecular mechanism underlying its progression remains unclear. Here, we found that conditional deletion of HIC1 in the mouse mammary gland might contribute to premalignant transformation in the early stage of tumor formation. Moreover, the chemokine CXCL14 secreted by HIC1-deleted BrCa cells bound to its novel cognate receptor GPR85 on mammary fibroblasts in the microenvironment and was responsible for activating these fibroblasts via the ERK1/2, Akt, and neddylation pathways, whereas the activated fibroblasts promoted BrCa progression via the induction of the epithelial–mesenchymal transition (EMT) by the CCL17/CCR4 axis.
Finally, we confirmed that the HIC1-CXCL14-CCL17 loop was associated with the malignant progression of BrCa. Therefore, the crosstalk between HIC1-deleted BrCa cells and mammary fibroblasts might play a critical role in BrCa development. Taken together, exploring the progression of BrCa from the perspective of microenvironment will be beneficial for identifying the potential prognostic marker of breast tumor and
providing the more effective treatment strategy.
Breast cancer (BrCa) is the malignant tumor that most seriously threatens female health; however, the molecular mechanism underlying its progression remains unclear. Here, we found that conditional deletion of HIC1 in the mouse mammary gland might contribute to premalignant transformation in the early stage of tumor formation. Moreover, the chemokine CXCL14 secreted by HIC1-deleted BrCa cells bound to its novel cognate receptor GPR85 on mammary fibroblasts in the microenvironment and was responsible for activating these fibroblasts via the ERK1/2, Akt, and neddylation pathways, whereas the activated fibroblasts promoted BrCa progression via the induction of the epithelial-mesenchymal transition (EMT) by the CCL17/CCR4 axis. Finally, we confirmed that the HIC1-CXCL14-CCL17 loop was associated with the malignant progression of BrCa. Therefore, the crosstalk between HIC1-deleted BrCa cells and mammary fibroblasts might play a critical role in BrCa development. Taken together, exploring the progression of BrCa from the perspective of microenvironment will be beneficial for identifying the potential prognostic marker of breast tumor and providing the more effective treatment strategy.
Interleukin-8 is a 72-residue peptide which is chemotactic for neutrophils and T-lymphocytes. It crystallizes in space group P3(1)21 or P3(2)21 with unit cell dimensions of a = b = 40.3 and c = 90.1 A. X-ray diffraction data have been measured to 1.6-A resolution.
Purified recombinant (r) macrophage inflammatory proteins (MIPs) 1 alpha, 1 beta, and 2 were assessed for effects on murine (mu) and human (hu) marrow colony-forming unit-granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) colonies. Recombinant MIP-1 alpha, -1 beta, and -2 enhanced muCFU-GM colonies above that stimulated with 10 to 100 U natural mu macrophage-colony-stimulating factor (M-CSF) or rmuGM-CSF, with enhancement seen on huCFU-GM colony formation stimulated with suboptimal rhuM-CSF or rhuGM-CSF; effects were neutralized by respective MIP-specific antibodies. Macrophage inflammatory proteins had no effects on mu or huBFU-E colonies stimulated with erythropoietin (Epo). However, natural MIP-1 and rMIP-1 alpha, but not rMIP-1 beta or -2, suppressed muCFU-GM stimulated with pokeweed mitogen spleen-conditioned medium (PWMSCM), huCFU-GM stimulated with optimal rhuGM-CSF plus rhu interleukin-3 (IL-3), muBFU-E and multipotential progenitors (CFU-GEMM) stimulated with Epo plus PWMSCM, and huBFU-E and CFU-GEMM stimulated with Epo plus rhuIL-3 or rhuGM-CSF. The suppressive effects of natural MIP-1 and rMIP-1 alpha were also apparent on a population of BFU-E, CFU-GEMM, and CFU-GM present in cell-sorted fractions of human bone marrow (CD34 HLA-DR+) highly enriched for progenitors with cloning efficiencies of 42% to 75%. These results, along with our previous studies, suggest that MIP-1 alpha, -1 beta, and -2 may have direct myelopoietic enhancing activity for mature progenitors, while MIP-1 alpha may have direct suppressing activity for more immature progenitors.
We have devised a simple and efficient cDNA cloning strategy that overcomes many of the difficulties encountered in obtaining full-length cDNA clones of low-abundance mRNAs. In essence, cDNAs are generated by using the DNA polymerase chain reaction technique to amplify copies of the region between a single point in the transcript and the 3' or 5' end. The minimum information required for this amplification is a single short stretch of sequence within the mRNA to be cloned. Since the cDNAs can be produced in one day, examined by Southern blotting the next, and readily cloned, large numbers of full-length cDNA clones of rare transcripts can be rapidly produced. Moreover, separation of amplified cDNAs by gel electrophoresis allows precise selection by size prior to cloning and thus facilitates the isolation of cDNAs representing variant mRNAs, such as those produced by alternative splicing or by the use of alternative promoters. The efficacy of this method was demonstrated by isolating cDNA clones of mRNA from int-2, a mouse gene that expresses four different transcripts at low abundance, the longest of which is approximately 2.9 kilobases. After less than 0.05% of the cDNAs produced had been screened, 29 independent int-2 clones were isolated. Sequence analysis demonstrated that the 3' and 5' ends of all four int-2 mRNAs were accurately represented by these clones.
5'-Noncoding sequences have been compiled from 699 vertebrate mRNAs. (GCC)GCCAGCCATGG emerges as the consensus sequence for initiation of translation in vertebrates. The most highly conserved position in that
motif is the purine in position -3 (three nucleotides upstream from the ATG codon); 97% of vertebrate mRNAs have a purine,
most often A, in that position- The periodical occurrence of G (in positions −3, −6, −9) is discussed. Upstream ATG codons
occur in fewer than 10% of vertebrate mRNAs-at-large; a notable exception are oncogene transcripts, two-thirds of which have
ATG codons preceding the start of the major open reading frame. The leader sequences of most vertebrate mRNAs fall in the
size range of 20 to 100 nucleotides. The significance of shorter and longer 5' -noncoding sequences is discussed.
Accumulation of leukocytes at sites of inflammation is essential for host defense, yet secretory products of the white cells may augment injury by damaging surrounding healthy tissues. Members of the chemokine family of chemotactic cytokines play a fundamental role in this process by attracting and stimulating specific subsets of leukocytes. In vitro studies suggest that chemokines participate in at least three phases of leukocyte recruitment. First, they foster tight adhesion of circulating leukocytes to the vascular endothelium by activating leukocytic integrins. Second, because of their chemoattractant properties, chemokines guide leukocytes through the endothelial junctions and underlying tissue to the inflammatory focus. Finally, chemokines activate effector functions of leukocytes, including production of reactive oxygen intermediates and exocytosis of degradative enzymes. Animal studies in which antibodies are used to neutralize the activity of individual members of the chemokine family confirm that these mediators contribute to the development of both acute and chronic inflammatory conditions. A number of mechanisms may operate in vivo to limit the proinflammatory properties of chemokines. Therapies that target chemokines directly or enhance the body's mechanisms for controlling their activity may prove to be reasonable approaches for treatment of inflammatory diseases.
A cofactor for HIV-1 (human immunodeficiency virus-type 1) fusion and entry was identified with the use of a novel functional
complementary DNA (cDNA) cloning strategy. This protein, designated “fusin,” is a putative G protein-coupled receptor with
seven transmembrane segments. Recombinant fusin enabled CD4-expressing nonhuman cell types to support HIV-1 Env-mediated cell
fusion and HIV-1 infection. Antibodies to fusin blocked cell fusion and infection with normal CD4-positive human target cells.
Fusin messenger RNA levels correlated with HIV-1 permissiveness in diverse human cell types. Fusin acted preferentially for
T cell line-tropic isolates, in comparison to its activity with macrophage-tropic HIV-1 isolates.
Purified recombinant (r) macrophage inflammatory proteins (MIPs) 1 alpha, 1 beta, and 2 were assessed for effects on murine (mu) and human (hu) marrow colony-forming unit-granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) colonies. Recombinant MIP-1 alpha, -1 beta, and -2 enhanced muCFU-GM colonies above that stimulated with 10 to 100 U natural mu macrophage-colony-stimulating factor (M-CSF) or rmuGM-CSF, with enhancement seen on huCFU-GM colony formation stimulated with suboptimal rhuM-CSF or rhuGM-CSF; effects were neutralized by respective MIP-specific antibodies. Macrophage inflammatory proteins had no effects on mu or huBFU-E colonies stimulated with erythropoietin (Epo). However, natural MIP-1 and rMIP-1 alpha, but not rMIP-1 beta or -2, suppressed muCFU-GM stimulated with pokeweed mitogen spleen-conditioned medium (PWMSCM), huCFU-GM stimulated with optimal rhuGM-CSF plus rhu interleukin-3 (IL-3), muBFU- E and multipotential progenitors (CFU-GEMM) stimulated with Epo plus PWMSCM, and huBFU-E and CFU-GEMM stimulated with Epo plus rhuIL-3 or rhuGM-CSF. The suppressive effects of natural MIP-1 and rMIP-1 alpha were also apparent on a population of BFU-E, CFU-GEMM, and CFU-GM present in cell-sorted fractions of human bone marrow (CD34 HLA-DR+) highly enriched for progenitors with cloning efficiencies of 42% to 75%. These results, along with our previous studies, suggest that MIP-1 alpha, -1 beta, and -2 may have direct myelopoietic enhancing activity for mature progenitors, while MIP-1 alpha may have direct suppressing activity for more immature progenitors.
Publisher Summary This chapter focuses on interleukin-8 (IL-8) and related chemotactic cytokines—namely, CXC and CC chemokines. IL-8 is the best known member of a new class of cytokines that are widely studied because of their ability to attract and activate leukocytes, and their potential role as mediators of inflammation. IL-8 was originally isolated from the culture supernatants of stimulated human blood monocytes and was identified as a protein of 72 amino acids with a molecular weight of 8383. The three-dimensional structure of IL-8 has been studied by nuclear magnetic resonance spectroscopy and X-ray crystallography. In concentrated solution, and on crystallization, IL-8 is present as a dimer. The first CC chemokine was identified after cloning by differential hybridization from human tonsillar lymphocytes and was termed LD78. The CC and CXC chemokines are similar in size and have an overall structure that is characterized by the two intrachain disulfide bonds, short N-terminal and long C-terminal sequences. It discusses the role of chemokines in pathology with skin inflammation because psoriasis was the first disease to be linked to overproduction of IL-8. Several independent studies document the occurrence of high levels of IL-8 in the synovial fluid of inflamed joints of patients with different forms of rheumatic diseases, osteoarthritis, and gout.
Human immunodeficiency virus-type 1 (HIV-1) entry requires fusion cofactors on the CD4+ target cell. Fusin, a heterotrimeric GTP-binding protein (G protein)-coupled receptor, serves as a cofactor for T cell line-tropic
isolates. The chemokines RANTES, MIP-1α, and MIP-1β, which suppress infection by macrophage-tropic isolates, selectively inhibited
cell fusion mediated by the corresponding envelope glycoproteins (Envs). Recombinant CC CKR5, a G protein-coupled receptor
for these chemokines, rendered CD4-expressing nonhuman cells fusion-competent preferentially with macrophage-tropic Envs.
CC CKR5 messenger RNA was detected selectively in cell types susceptible to macrophage-tropic isolates. CC CKR5 is thus a
fusion cofactor for macrophage-tropic HIV-1 strains.
Our studiesin vitro demonstrate that neutrophil mediated injury of isolated cardiac myocytes requires the presence of ICAM-1 on the surface of the myocyte and CD11b/CD18 activation on the neutrophil. In post-ischemic cardiac lymph, there is rapid appearance of C5a activity during the first hours of reperfusion. Interleukin-6 activity is present throughout the first 72 h of reperfusion and is sufficient to induce ICAM-1 on the surface of the cardiac myocyte.In situ hybridization studies suggest that ICAM-1 mRNA is found in viable myocardial cells on the edge of the myocardial infarction within 1 h of reperfusion. ICAM-1 protein expression on cardiac myocytes is seen after 6 h of reperfusion, and increases thereafter. Non-ischemic tissue demonstrates no early induction of ICAM-1 mRNA or ICAM-1 protein on myocardial cells. In our most recent experiments, we have determined that reperfusion is an absolute requirement for the early induction of myocardial ICAM-1 mRNA in previously ischemic myocardial cells. To further assess this, we have cloned and sequenced a canine interleukin-6 (IL-6) cDNA. The data suggest that early induction of IL-6 mRNA is also reperfusion dependent as it could be demonstrated in the same ischemic and reperfused segments in which ICAM-1 mRNA was found. Peak expression of IL-6 mRNA occurred much earlier than that for ICAM-1 mRNA. Similar experiments were then performed with a molecular probe for interleukin-8 (IL-8). This chemokine is a potent neutrophil stimulant and has a higher degree of specificity for neutrophils than classic chemoattractants such as C5a. The results suggest a similar pattern of induction that occurs within the first hour and is markedly, increased by reperfusion. The relationship of reperfusion to ICAM-1 and cytokine induction is discussed.
A number of studies of inflammation and of cell growth and transformation have recently converged by defining two related families of cytokines. The first, represented by macrophage inflammatory protein 1, is composed of several gene products that have been identified in activated T cells, macrophages, and fibroblasts. The biological activities of this family are still being characterized but so far include effects on neutrophils, monocytes, and hematopoietic cells. The second, represented by macrophage inflammatory protein 2, includes platelet products such as platelet factor 4 and beta-thromboglobulin as well as several other recently described gene products that have effects on a number of cell types including neutrophils, fibroblasts, hematopoietic cells, and melanoma cells. The two families are structurally related and may have evolved from a common ancestral gene that duplicated and then diverged. Their differential control and expression in a wide variety of cell types suggests that they may have multiple functions in regulating inflammation and cell growth.
The infiltration of leucocytes into the joint of rheumatoid arthritis (RA) is believed to be mediated by chemotactic factors released by activated cells. In this study, examination was made of the gene expression and production of the chemokine superfamily in RA patients by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunoprecipitation. Cultured synovial fibroblasts were found capable of expressing and producing IL-8, GRO, monocyte chemotactic and activating factor (MCAF), macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta and RANTES in response to IL-1 alpha. The expression of IL-8, GRO, MCAF, MIP-1 alpha, and MIP-1 beta was clearly shown to increase in freshly isolated synovial fluid mononuclear cells (SFMC) of RA patients, in contrast to peripheral blood mononuclear cells (PBMC) of RA patients and normal subjects. The gene expression of RANTES appeared to be the same for RA SFMC, RA PBMC, and normal PBMC. Thus, the over-expression of various chemokines may promote the recruitment of inflammatory cells into rheumatoid inflamed joints.
Macrophage inflammatory protein (MIP)-1 alpha, part of a family termed chemokines, has been implicated in suppression of hemopoietic stem and progenitor cell proliferation. The chemokine family has been organized into two subgroups with MIP-1 alpha, MIP-1 beta, macrophage chemotactic and activating factor (MCAF) and RANTES belonging to one subgroup, and GRO-alpha, MIP-2 alpha (GRO-beta), MIP-2 beta (GRO-gamma), platelet factor 4 (PF4), IL-8, and neutrophil activating peptide (NAP)-2 belonging to the other. These molecules were evaluated for effects on colony formation by human bone marrow multipotential (CFU-GEMM), erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells. None of the chemokines stimulated colony formation in the absence of CSF, or influenced colony formation stimulated by a single growth factor such as granulocyte-macrophage-CSF or erythropoietin. However, MIP-1 alpha, MIP-2 alpha, PF4, IL-8, and MCAF suppressed in dose-response fashion colony formation of immature subsets of myeloid progenitor cells stimulated by GM-CSF plus steel factor. Effects were apparent on low density and CD34 HLA-DR(+)-sorted marrow cells in which up to 88.4% of the cells were composed of progenitor cells, suggesting direct effects on the progenitors themselves. Up to 2500-fold less of each chemokine could be used to demonstrate synergistic suppression when any two of these five chemokines were used together at low concentrations, effects also apparently directly on the progenitors. In contrast, MIP-1 beta, MIP-2 beta, GRO-alpha, NAP-2, and RANTES were not suppressive nor did they synergize with MIP-1 alpha, MIP-2 alpha, PF4, IL-8, or MCAF to suppress. However, a fivefold excess of MIP-1 beta blocked the suppressive effects of MIP-1 alpha. Similarly, a fivefold excess of either MIP-2 beta or GRO-alpha blocked the suppressive effects of IL-8 and PF4. These suppressing, synergizing and blocking effects may be of relevance to blood cell regulation.
The relatively recent appreciation of a new class of cytokines, the chemokines, has done much to enhance our understanding of the extracellular signals involved in the movement of various populations of white blood cells. Investigation of the molecular underpinnings of chemokine function and their involvement in inflammatory processes of all kinds is beginning to yield information about the mechanisms of pathogenesis of a number of conditions, as well as providing hope for new therapeutic insights.
It has been very difficult for investigators involved in studies of the chemotactic factors to agree on terminology; hence the plethora of strange names for these cytokines. It was therefore especially gratifying that this intensely involved and partisan group of researchers could meet and after heated discussion reach an almost unanimous agreement to endorse the chemokine α and β nomenclature for the subfamilies of chemoattractant cytokines whose genes are located on human chromosome 4q and 17q regions respectively.
Leukocytes migrate from the blood to sites of inflammation in response to locally produced chemoattractants that activate specific cell surface receptors. The primary structures of leukocyte receptors for N-formyl peptides, C5a, platelet-activating factor, and 8 of the 18 known human chemokines (interleukin-8 and related molecules) have been deduced from cloned cDNAs. All of these are seven-transmembrane-domain rhodopsin-like G protein-coupled receptors. Biochemical and molecular genetic analysis of the chemoattractant receptors indicates that the chemoattractants may have both broadly overlapping as well as specialized roles in the regulation of acute and chronic inflammation. Interestingly, the chemokine receptors have functional homologues in human cytomegalovirus and Herpesvirus saimiri. Moreover, the Duffy antigen, which mediates invasion of erythrocytes by Plasmodium vivax, a major cause of malaria, is also a chemokine binding protein. These surprising developments suggest that in addition to leukocyte-mediated inflammation, the chemokines may also be involved in erythrocyte function and, through molecular mimicry, in microbial pathogenesis.
CC chemokines are small inducible proteins that are related to interleukin 8. Recent studies have shown that several CC chemokines, MCP-1, MCP-3, RANTES and MIP-1 alpha, act on basophils and/or eosinophils via GTP-binding protein-coupled receptors. Marco Baggiolini and Clemens Dahinden discuss the involvement of CC chemokines in the recruitment and activation of the main effector cells of allergic inflammation.
The beta-chemokines MIP-1alpha, MIP-1beta and RANTES inhibit infection of CD4+ T cells by primary, non-syncytium-inducing (NSI) HIV-1 strains at the virus entry stage, and also block env-mediated cell-cell membrane fusion. CD4+ T cells from some HIV-1-exposed uninfected individuals cannot fuse with NSI HIV-1 strains and secrete high levels of beta-chemokines. Expression of the beta-chemokine receptor CC-CKR-5 in CD4+, non-permissive human and non-human cells renders them susceptible to infection by NSI strains, and allows env-mediated membrane fusion. CC-CKR-5 is a second receptor for NSI primary viruses.
Human immunodeficiency virus-type 1 (HIV-1) entry requires fusion cofactors on the CD4+ target cell. Fusin, a heterotrimeric GTP-binding protein (G protein)-coupled receptor, serves as a cofactor for T cell line-tropic isolates. The chemokines RANTES, MIP-1alpha, and MIP-1beta, which suppress infection by macrophage-tropic isolates, selectively inhibited cell fusion mediated by the corresponding envelope glycoproteins (Envs). Recombinant CC CKR5, a G protein-coupled receptor for these chemokines, rendered CD4-expressing nonhuman cells fusion-competent preferentially with macrophage-tropic Envs. CC CKR5 messenger RNA was detected selectively in cell types susceptible to macrophage-tropic isolates. CC CKR5 is thus a fusion cofactor for macrophage-tropic HIV-1 strains.
Chemokines are a group of small, homologous proteins that regulate leukocyte migration, hemopoiesis, and HIV-1 absorption. We report here the cloning and characterization of a novel murine and human C-C chemokine termed Exodus-2 for its similarity to Exodus-1/MIP-3alpha/LARC, and its chemotactic ability. This novel chemokine has a unique 36 or 37 (murine and human, respectively) amino acid carboxyl-terminal extension not seen in any other chemokine family member. Purified recombinant Exodus-2 was found to have two activities classically associated with chemokines: inhibiting hemopoiesis and stimulating chemotaxis. However, Exodus-2 also had unusual characteristics for C-C chemokines. It selectively stimulated the chemotaxis of T-lymphocytes and was preferentially expressed in lymph node tissue. The combination of these characteristics may be a functional correlate for the unique carboxyl-terminal structure of Exodus-2.
The goal of these experiments was to test the hypothesis that after a nonlethal episode of hemorrhagic shock, factors carried in the mesenteric lymph would promote endothelial cell injury and activate neutrophils to a greater extent than portal vein plasma. Catheters were placed in the efferent lymphatic duct draining the mesenteric lymph node complex, after which male rats were subjected to sham or actual shock (30 mmHg for 90 min), and lymph was collected. Portal vein plasma was collected from the sham-shock and shocked rats at 6 h post-shock or sham-shock. When the effect of lymph or portal blood plasma was tested on endothelial cell (HUVEC) monolayer permeability, it was found that post-shock lymph, but not post-shock portal vein plasma, increased HUVEC permeability to both 10 kDa and 40 kDa permeability probes. Subsequent experiments documented that only post-shock lymph was cytotoxic to endothelial cells as manifest both by decreased trypan blue dye exclusion and the increased release of Chromium-51 from chromium-loaded endothelial cells. Furthermore post-shock lymph induced a greater increase in neutrophil superoxide formation than pre-shock lymph, pre-shock, or post-shock portal vein plasma. Lastly, neutrophil-mediated endothelial cell injury was potentiated by the presence of post-shock lymph, and the magnitude of HUVEC injury was greater in endothelial cells incubated with post-shock lymph plus neutrophils than in monolayers incubated with post-shock lymph or neutrophils alone. These results suggest that post-shock lymph is cytotoxic to endothelial cells and activates neutrophils. Since the lung is the first organ that is exposed to mesenteric lymph, lung injury after hemorrhagic shock may be mediated by factors contained in mesenteric lymph.