Anti-interferon-inducible chemokine, CXCL10, reduces colitis by impairing T helper-1 induction and recruitment in mice

Inflammatory Gene Panel Guiding the Study of Genetics in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a complex disease that develops through a sequence of molecular events that are still poorly defined. This process is driven by a multitude of context-dependent genes that play different roles based on their environment. The complexity and multi-faceted nature of these genes make it difficult to study the genetic basis of IBD. The goal of this article is to review the key genes in the pathophysiology of IBD and highlight new technology that can be used in further research. This paper examines Nanostring RNA probe technology, which uses tissue analyzed without the use of enzymes, transcription, or amplification. Nanostring offers several panels of genes to test, including an inflammation panel of 234 genes. This article analyzes this panel and reviews the literature for each gene's effect in IBD for use as a framework to review the pathophysiology of the disease. The panel was narrowed to 26 genes with significant evidence of mechanistic potential in IBD, which were then categorized into specific areas of pathogenesis. These include gut barrier breakdown, inappropriate recognition of commensal bacteria, immune cell activation, proinflammatory cytokine release, and subsequent impairment of the anti-inflammatory response. The eventual goal of this paper is the creation of a customized panel of IBD genes that can be used to better understand the genetic mechanism of IBD and aid in the development of future therapies in IBD.

Selenium Yeast Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in Mice by Reducing Proinflammatory Cytokines and Regulating the Gut Microbiota and Their Metabolites

Background

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal inflammatory disease. Selenium has been reported to have therapeutic potential in IBD. Selenium yeast is a common selenium supplement that is convenient to access. This study explored the effect of selenium yeast on dextran sulfate sodium- (DSS-)induced chronic colitis in mice.

Methods

Mice were randomly divided into four groups: the control group, selenium yeast group, chronic colitis group, and chronic colitis+selenium yeast group (n=6). Mice were killed on the 26th day. The disease activity index (DAI) score and histological damage score were calculated. Cytokines, serum selenium, colonic tissue selenium, gut microbiota and their metabolites short-chain fatty acids (SCFAs) were evaluated.

Results

Selenium yeast lowered IL-1β, IL-6, TNF-α, IL-17A, IL-22 and IFN-γ (P<0.05). In addition, selenium yeast significantly elevated Turicibacter, Bifidobacterium, Allobaculum, Prevotella, Halomonas, Adlercreutzia (P<0.05), and butyric acid (P<0.05).

Conclusion

Selenium yeast could improve DSS-induced chronic colitis in mice by regulating cytokines, gut microbiota and their metabolites.

Miniaturized implantable temperature sensors for the long-term monitoring of chronic intestinal inflammation

Diagnosing and monitoring inflammatory bowel diseases, such as Crohn's disease, involves the use of endoscopic imaging, biopsies and serology. These infrequent tests cannot, however, identify sudden onsets and severe flare-ups to facilitate early intervention. Hence, about 70% of patients with Crohn's disease require surgical intestinal resections in their lifetime. Here we report wireless, miniaturized and implantable temperature sensors for the real-time chronic monitoring of disease progression, which we tested for nearly 4 months in a mouse model of Crohn's-disease-like ileitis. Local measurements of intestinal temperature via intraperitoneally implanted sensors held in place against abdominal muscular tissue via two sutures showed the development of ultradian rhythms at approximately 5 weeks before the visual emergence of inflammatory skip lesions. The ultradian rhythms showed correlations with variations in the concentrations of stress hormones and inflammatory cytokines in blood. Decreasing average temperatures over the span of approximately 23 weeks were accompanied by an increasing percentage of inflammatory species in ileal lesions. These miniaturized temperature sensors may aid the early treatment of inflammatory bowel diseases upon the detection of episodic flare-ups.

Identification of Shared Biomarkers and Immune Infiltration Signatures between Vitiligo and Hashimoto's Thyroiditis

Background

Vitiligo and Hashimoto's thyroiditis (HT) are concomitant autoimmune diseases characterized by the destruction of melanocytes or thyrocytes. We aimed to explore the immunological mechanism of this comorbidity and screen their potential biomarkers.

Methods

We downloaded the microarray datasets from the GEO database. Differentially expressed genes (DEGs) and immune-related genes (IRGs) were selected. The immune-related differentially expressed genes (IRDEGs) were obtained by taking the intersection. Candidate biomarkers were elected by Cytoscape software. CIBERSORT was used to depict immune cell infiltration prospects. Correlation analysis was conducted between infiltrating cells and several indicators. The results were validated by real-time quantitative PCR (RT-qPCR).

Results

Three datasets and 60 IRDEGs were obtained in total. Pathway enrichment analysis showed that the T cell receptor signaling pathway, IL-17 signaling pathway, receptor-ligand activity, and signaling receptor activator activity were significantly enriched. We screened out four hub genes, including IFNG, STAT1, IL1B, and CXCL10. The ROC curve indicated the highest diagnostic value of CXCL10 in both vitiligo and HT. Immuno-infiltration analysis revealed significant changes in T cell subsets and macrophage subtypes, which were correlated with four hub genes, melanocyte markers, and thyroid-specific antigens. qPCR validated the hub genes in peripheral blood mononuclear cells from patients with comorbidity.

Conclusion

IFNG, STAT1, IL1B, and CXCL10, were the key IRDEGs to vitiligo and HT. These genes may participate in the comorbidity by remodeling the immune cell infiltration pattern, and cross-expressed antigens may mediate the common damage of melanocytes and thyroid tissues.

Cytokine induced inflammatory bowel disease model using organ-on-a-chip technology

Over 2 million people in North America suffer from inflammatory bowel disease (IBD), a chronic and idiopathic inflammatory condition. While previous research has primarily focused on studying immune cells as a cause and therapeutic target for IBD, recent findings suggest that non-immune cells may also play a crucial role in mediating cytokine and chemokine signaling, and therefore IBD symptoms. In this study, we developed an organ-on-a-chip co-culture model of Caco2 epithelial and HUVEC endothelial cells and induced inflammation using pro-inflammatory cytokines TNF-α and IFN-γ. We tested different concentration ranges and delivery orientations (apical vs. basal) to develop a consistently inducible inflammatory response model. We then measured pro-inflammatory cytokines and chemokines IL-6, IL-8, and CXCL-10, as well as epithelial barrier integrity. Our results indicate that this model 1. induces IBD-like cytokine secretion in non-immune cells and 2. decreases barrier integrity, making it a feasible and reliable model to test the direct actions of potential anti-inflammatory therapeutics on epithelial and endothelial cells.

PROTAC targeting cyclophilin A controls virus-induced cytokine storm

Cytokine storms caused by viruses are associated with elevated cytokine levels and uncontrolled inflammatory responses that can lead to acute respiratory distress syndrome. Current antiviral therapies are not sufficient to prevent or treat these complications. Cyclophilin A (CypA) is a key factor that regulates the production of multiple cytokines and could be a potential therapeutic target for cytokine storms. Here, three proteolysis targeting chimeras (PROTACs) targeting CypA were designed. These PROTACs bind to CypA, enhance its ubiquitination, and promote its degradation in both cell lines and mouse organs. During influenza B virus (IBV) infection, PROTAC-mediated CypA depletion reduces P65 phosphorylation and NF-κB-mediated proinflammatory cytokine production in A549 cells. Moreover, Comp-K targeting CypA suppresses excessive secretion of proinflammatory cytokines in bronchoalveolar lavage fluid, reduces lung injury, and enhances survival rates of IBV-infected mice. Collectively, we provide PROTACs targeting CypA, which are potential candidates for the control of cytokine storms.

Analysis of the interferon-γ-induced secretome of intestinal endothelial cells: putative impact on epithelial barrier dysfunction in IBD

The development of inflammatory bowel diseases (IBD) involves the breakdown of two barriers: the epithelial barrier and the gut-vascular barrier (GVB). The destabilization of each barrier can promote initiation and progression of the disease. Interestingly, first evidence is available that both barriers are communicating through secreted factors that may accordingly serve as targets for therapeutic modulation of barrier functions. Interferon (IFN)-γ is among the major pathogenesis factors in IBD and can severely impair both barriers. In order to identify factors transmitting signals from the GVB to the epithelial cell barrier, we analyzed the secretome of IFN-γ-treated human intestinal endothelial cells (HIEC). To this goal, HIEC were isolated in high purity from normal colon tissues. HIEC were either untreated or stimulated with IFN-γ (10 U/mL). After 48 h, conditioned media (CM) were harvested and subjected to comparative hyper reaction monitoring mass spectrometry (HRM™ MS). In total, 1,084 human proteins were detected in the HIEC-CM. Among these, 43 proteins were present in significantly different concentrations between the CM of IFN-γ- and control-stimulated HIEC. Several of these proteins were also differentially expressed in various murine colitis models as compared to healthy animals supporting the relevance of these proteins secreted by inflammatory activated HIEC in the inter-barrier communication in IBD. The angiocrine pathogenic impact of these differentially secreted HIEC proteins on the epithelial cell barrier and their perspectives as targets to treat IBD by modulation of trans-barrier communication is discussed in detail.

CXCL10 as a shared specific marker in rheumatoid arthritis and inflammatory bowel disease and a clue involved in the mechanism of intestinal flora in rheumatoid arthritis

This study aimed to identify shared specific genes associated with rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) through bioinformatic analysis and to examine the role of the gut microbiome in RA. The data were extracted from the 3 RA and 1 IBD gene expression datasets and 1 RA gut microbiome metagenomic dataset. Weighted correlation network analysis (WGCNA) and machine learnings was performed to identify candidate genes associated with RA and IBD. Differential analysis and two different machine learning algorithms were used to investigate RA's gut microbiome characteristics. Subsequently, the shared specific genes related to the gut microbiome in RA were identified, and an interaction network was constructed utilizing the gutMGene, STITCH, and STRING databases. We identified 15 candidates shared genes through a joint analysis of the WGCNA for RA and IBD. The candidate gene CXCL10 was identified as the shared hub gene by the interaction network analysis of the corresponding WGCNA module gene to each disease, and CXCL10 was further identified as the shared specific gene by two machine learning algorithms. Additionally, we identified 3 RA-associated characteristic intestinal flora (Prevotella, Ruminococcus, and Ruminococcus bromii) and built a network of interactions between the microbiomes, genes, and pathways. Finally, it was discovered that the gene CXCL10 shared between IBD and RA was associated with the three gut microbiomes mentioned above. This study demonstrates the relationship between RA and IBD and provides a reference for research into the role of the gut microbiome in RA.

Association between inflammatory bowel disease and interleukins, chemokines: a two-sample bidirectional mendelian randomization study

Background

Mendelian randomization (MR) was used to evaluate the bidirectional causal relationship between inflammatory bowel disease (IBD) and interleukins (ILs), chemokines.

Methods

Genetic instruments and summary data of five ILs and six chemokines were obtained from a genome-wide association study database, and instrumental variables related to IBD were obtained from the FinnGen Consortium. Inverse variance weighting (IVW) was used as the main MR analysis method, and several other MR methods including MR-Egger and weighted median were used to confirm the reliability of the results. Sensitivity analyses such as heterogeneity and pleiotropy were also performed.

Results

The IVW method provided evidence to support that genetically predicted IL-16, IL-18, and CXCL10 significantly positively correlated with IBD, while IL-12p70 and CCL23 significantly negatively correlated with IBD. IL-16 and IL-18 had a suggestive association with an increased risk of ulcerative colitis (UC), and CXCL10 had a suggestive association with an increased risk of Crohn's disease (CD). However, there was no evidence to support that IBD and two main subtypes (UC and CD) are associated with changes in the levels of ILs and chemokines. The results of the sensitivity analyses were robust and no evidence of heterogeneity and horizontal pleiotropy was observed.

Conclusions

The present study showed that some ILs and chemokines affect IBD, but IBD and its main subtypes (UC and CD) have no effect on the level changes of ILs and chemokines.

Controlling in and out - the future of interfering with immune cell trafficking in inflammatory bowel disease

INTRODUCTION

Immune cell trafficking is a key requirement in the pathogenesis of inflammatory bowel diseases. Consistently, therapeutic strategies to target immune cell trafficking have been established and continue to be developed for the treatment of ulcerative colitis and Crohn's disease.

AREAS COVERED

In this review, we briefly summarize the most important checkpoints of intestinal immune cell trafficking and their importance during IBD. Moreover, we provide an overview of associated therapeutic targets and previous as well as current efforts on treatment strategies related to these targets.

EXPERT OPINION

Finally, we comment on potential future developments that might shape the field of immune cell trafficking in the context of IBD.

Identification of CXCL10 and CXCL11 as the candidate genes involving the development of colitis-associated colorectal cancer

Background: Ulcerative colitis (UC) is a well-known risk factor for developing colitis-associated colorectal cancer (CAC). However, the molecular mechanism of the pathogenesis of CAC remains unclear. This study aimed to explore candidate genes involved in the tumorigenesis of CAC.

Methods: GSE75214 and the Cancer Genome Atlas Program (TCGA) dataset were used to analyze the differentially expressed genes (DEGs) in UC and colorectal cancer (CRC), respectively. Survival-hub genes were identified from these DEGs by sequentially constructing a protein–protein interaction network, selecting hub genes, and conducting survival analysis. Regulatory signatures were also predicted on these genes through the online database. Apc^min/+ and UC mice models were used to validate the expression of the above-predicted molecules. Gene set enrichment analysis and CIBERSORT were performed to explore the enriched molecular pathways and associated tissue-infiltrating immune cells of genes.

Results: Here, 376 common DEGs were identified from the GSE75214 and TCGA datasets. Through survival-hub gene selection and in vivo experiments, we confirmed that CXCL10 and CXCL11 were significantly upregulated in UC and CRC. We also proved that miR-34a-5p and miR-203a-5p were potential regulators of CXCL10 and CXCL11. Meanwhile, CXCL10 and CXCL11 may activate the JAK–STAT signaling pathway via the interaction with cytokine receptors in UC. Furthermore, CXCL10 and CXCL11 were positively associated with the tissue infiltration of proinflammatory M1 macrophages in UC and CRC.

Conclusion: CXCL10 and CXCL11 may act as the candidate genes involved in the tumorigenesis of CAC and potential therapeutic targets to prevent the development of CAC from UC.

A Teleost CXCL10 Is Both an Immunoregulator and an Antimicrobial

Chemokines are a group of cytokines that play important roles in cell migration, inflammation, and immune defense. In this study, we identified a CXC chemokine, CXCL10, from Japanese flounder Paralichthys olivaceus (named PoCXCL10) and investigated its immune function. Structurally, PoCXCL10 possesses an N-terminal coil, three β-strands, and a C-terminal α-helix with cationic and amphipathic properties. PoCXCL10 expression occurred in multiple tissues and was upregulated by bacterial pathogens. Recombinant PoCXCL10 (rPoCXCL10) promoted the migration, cytokine expression, and phagocytosis of flounder peripheral blood leukocytes (PBLs). rPoCXCL10 bound to and inhibited the growth of a variety of common Gram-negative and Gram-positive fish pathogens. rPoCXCL10 killed the pathogens by causing bacterial membrane permeabilization and structure destruction. When introduced in vivo, rPoCXCL10 significantly inhibited bacterial dissemination in fish tissues. A peptide derived from the C-terminal α-helix exhibited bactericidal activity and competed with rPoCXCL10 for bacterial binding. Deletion of the α-helix affected the in vitro bactericidal activity but not the chemotaxis or in vivo antimicrobial activity of PoCXCL10. Together, these results indicate that PoCXCL10 exerts the role of both an immunoregulator and a bactericide/bacteriostatic via different structural domains. These findings provide new insights into the immune function and working mechanism of fish CXC chemokines.

Interleukin-26 Expression in Inflammatory Bowel Disease and Its Immunoregulatory Effects on Macrophages

Background and Aim

Interleukin-26 (IL-26) has been implicated in several chronic inflammatory diseases. However, its role in inflammatory bowel disease (IBD) remains to be elucidated. We aimed to investigate IL-26 expression in IBD and its immunoregulatory effects on macrophages.

Methods

We assessed IL-26 expression in the intestinal mucosa and blood samples of IBD patients and healthy controls (HC). The associations between the clinical characteristics of IBD and IL-26 expression levels in serum and peripheral blood mononuclear cells (PBMCs) were investigated. In addition, the transcriptional changes in THP-1 macrophages exposed to IL-26 were determined by RNA sequencing and validated with qRT-PCR, ELISA and western blots.

Results

Compared with HC, in IBD patients, IL-26 expression levels were elevated in the inflamed intestinal mucosa, and reduced in serum and PBMCs. IL-26 mRNA levels in PBMCs, but not serum IL-26 levels, were inversely correlated with disease activity in IBD. Furthermore, IL-26 mRNA levels in PBMCs were significantly lower in patients with complicated Crohn's disease. A total of 1,303 differentially expressed protein-coding genes were identified between untreated and IL-26-treated macrophages. The up-regulated genes showed enrichment in some inflammatory and immune-related processes and pathways. Additionally, GSEA showed that neutrophil, monocyte, and lymphocyte chemotaxis was significantly enriched in IL-26-treated macrophages. Further validation revealed that IL-26 promotes the secretion of multiple inflammatory cytokines and chemokines and upregulates the expression of adhesion molecules, MMP-8, and MMP-9 while inhibiting MMP-1 in macrophages.

Conclusion

Compared with HC, in IBD patients, IL-26 levels were elevated in the inflamed intestinal mucosa, and reduced in the peripheral blood. The transcriptional changes in macrophages exposed to IL-26 suggest that IL-26 may amplify the aberrant immune response in IBD by activating macrophages.

Survival of Stem Cells and Progenitors in the Intestine Is Regulated by LPA5-Dependent Signaling

BACKGROUND & AIMS

Regeneration of the epithelium by stem cells in the intestine is supported by intrinsic and extrinsic factors. Lysophosphatidic acid (LPA), a bioactive lipid mediator, regulates many cellular functions, including cell proliferation, survival, and cytokine secretion. Here, we identify LPA₅ receptor as a potent regulator of the survival of stem cells and transit-amplifying cells in the intestine.

METHODS

We have used genetic mouse models of conditional deletion of Lpar5, Lpar5^f/f;Rosa-Cre^ERT (Lpar5^KO), and intestinal epithelial cell-specific Lpar5^f/f;AhCre (Lpar5^IECKO) mice. Mice were treated with tamoxifen or β-naphthoflavone to delete Lpar5 expression. Enteroids derived from these mice were used to determine the effect of Lpar5 loss on the apoptosis and proliferation of crypt epithelial cells.

RESULTS

Conditional loss of Lpar5 induced ablation of the intestinal mucosa, which increased morbidity of Lpar5^KO mice. Epithelial regeneration was compromised with increased apoptosis and decreased proliferation of crypt epithelial cells by Lpar5 loss. Interestingly, intestinal epithelial cell-specific Lpar5 loss did not cause similar phenotypic defects in vivo. Lpar5 loss reduced intestinal stem cell marker gene expression and reduced lineage tracing from Lgr5⁺ ISCs. Lpar5 loss induced CXCL10 expression which exerts cytotoxic effects on intestinal stem cells and progenitors in the intestinal crypts. By co-culturing Lpar5^KO enteroids with wild-type or Lpar5^KO splenocytes, we demonstrated that lymphocytes protect the intestinal crypts via a LPA₅-dependent suppression of CXCL10.

CONCLUSIONS

LPA₅ is essential for the regeneration of intestinal epithelium. Our findings reveal a new finding that LPA₅ regulates survival of stem cells and transit-amplifying cells in the intestine.

The Role of the Lymphatic System in the Pathogenesis and Treatment of Inflammatory Bowel Disease

Although the number of therapeutic options for the treatment of inflammatory bowel disease (IBD) has increased in recent years, patients suffer from decreased quality of life due to non-response or loss of response to the currently available treatments. An increased understanding of the disease’s etiology could provide novel insights for treatment strategies in IBD. Lymphatic system components are generally linked to immune responses and presumably related to inflammatory diseases pathophysiology. This review aims to summarize findings on immune-mediated mechanisms in lymphoid tissues linked with IBD pathogenesis and (potential) novel treatments. Enhanced innate and adaptive immune responses were observed in mesenteric lymph nodes (MLNs) and other lymphoid structures, such as Peyer’s patches, in patients with IBD and in animal models. Furthermore, the phenomenon of lymphatic obstruction in the form of granulomas in MLNs and lymphatic vessels correlates with disease activity. There is also evidence that abnormalities in the lymphatic stromal components and lymph node microbiome are common in IBD and could be exploited therapeutically. Finally, novel agents targeting lymphocyte trafficking have been added to the treatment armamentarium in the field of IBD. Overall, gut-associated lymphoid tissue plays a key role in IBD immunopathogenesis, which could offer novel therapeutic targets.

Endothelial STING controls T cell transmigration in an IFNI-dependent manner

The stimulator of IFN genes (STING) protein senses cyclic dinucleotides released in response to double-stranded DNA and functions as an adaptor molecule for type I IFN (IFNI) signaling by activating IFNI-stimulated genes (ISG). We found impaired T cell infiltration into the peritoneum in response to TNF-α in global and EC-specific STING-/- mice and discovered that T cell transendothelial migration (TEM) across mouse and human endothelial cells (EC) deficient in STING was strikingly reduced compared with control EC, whereas T cell adhesion was not impaired. STING-/- T cells showed no defect in TEM or adhesion to EC, or immobilized endothelial cell-expressed molecules ICAM1 and VCAM1, compared with WT T cells. Mechanistically, CXCL10, an ISG and a chemoattractant for T cells, was dramatically reduced in TNF-α-stimulated STING-/- EC, and genetic loss or pharmacologic antagonisms of IFNI receptor (IFNAR) pathway reduced T cell TEM. Our data demonstrate a central role for EC-STING during T cell TEM that is dependent on the ISG CXCL10 and on IFNI/IFNAR signaling.

Targeting Immune Cell Trafficking - Insights From Research Models and Implications for Future IBD Therapy

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC) are multifactorial diseases with still unknown aetiology and an increasing prevalence and incidence worldwide. Despite plentiful therapeutic options for IBDs, the lack or loss of response in certain patients demands the development of further treatments to tackle this unmet medical need. In recent years, the success of the anti-α4β7 antibody vedolizumab highlighted the potential of targeting the homing of immune cells, which is now an important pillar of IBD therapy. Due to its complexity, leukocyte trafficking and the involved molecules offer a largely untapped resource for a plethora of potential therapeutic interventions. In this review, we aim to summarise current and future directions of specifically interfering with immune cell trafficking. We will comment on concepts of homing, retention and recirculation and particularly focus on the role of tissue-derived chemokines. Moreover, we will give an overview of the mode of action of drugs currently in use or still in the pipeline, highlighting their mechanisms and potential to reduce disease burden.

Controlling leukocyte trafficking in IBD

Inflammatory bowel disease (IBD) is characterized by the accumulation of immune cells, myeloid cells and lymphocytes in the inflamed intestine. The presence and persistence of these cells, together with the production of pro-inflammatory mediators, perpetuate intestinal inflammation in both ulcerative colitis and Crohn's disease. Thus, blockade of leukocyte migration to the intestine is a main strategy used to control the disease and alleviate symptoms. Vedolizumab is the only anti-integrin drug approved for the treatment of IBD but several other drugs also targeting integrins, chemokines or receptors involved in leukocyte intestinal trafficking are under development and investigated for their efficacy and safety in IBD. The challenge now is to better understand the specific mechanism of action underlying each drug and to identify biomarkers that would guide drug selection in the individual patient.

Th1 Chemokines in Autoimmune Endocrine Disorders

CONTEXT

The CXC chemokine receptor CXCR3 and its chemokines CXCL10, CXCL9, and CXCL11 are implicated in the pathogenesis of autoimmune diseases. Here, we review these chemokines in autoimmune thyroiditis (AT), Graves disease (GD), thyroid eye disease (TED), type 1 diabetes (T1D), and Addison's disease (AAD).

EVIDENCE ACQUISITION

A PubMed review of the literature was conducted, searching for the above-mentioned chemokines in combination with AT, GD, TED, T1D, and AAD.

EVIDENCE SYNTHESIS

Thyroid follicular cells in AT and GD, retroorbital cells in TED (fibroblasts, preadipocytes, myoblasts), β cells and islets in T1D, and adrenal cells in AAD respond to interferon-γ (IFN-γ) stimulation producing large amounts of these chemokines. Furthermore, lymphocytes and peripheral blood mononuclear cells (PBMC) are in part responsible for the secreted Th1 chemokines. In AT, GD, TED, T1D, and AAD, the circulating levels of these chemokines have been shown to be high. Furthermore, these chemokines have been associated with the early phases of the autoimmune response in all the above-mentioned disorders. High levels of these chemokines have been associated also with the "active phase" of the disease in GD, and also in TED. Other studies have shown an association with the severity of hypothyroidism in AD, of hyperthyroidism in GD, with severity of TED, or with fulminant T1D.

CONCLUSION

The reviewed data have shown the importance of the Th1 immune response in different endocrine autoimmune diseases, and many studies have suggested that CXCR3 and its chemokines might be considered as potential targets of new drugs for the treatment of these disorders.

A new target for the treatment of inflammatory bowel disease: Interleukin-37

Interleukin (IL)-37 belongs to the IL-1 cytokine family. It has anti-inflammatory effects on numerous autoimmune diseases such as asthma, psoriasis, inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), multiple sclerosis (MS) and rheumatoid arthritis (RA). Mechanistically, IL-37 plays an anti-inflammatory role by regulating the expression of inflammatory factors in two ways: binding extracellular receptors IL-18R or transferring into the nucleus with Smad3. IBD is a kind of idiopathic intestinal inflammatory disease with unknown etiology and pathogenesis. Recent researches had proved that IL-37 is negatively involved in the pathogenesis and development of IBD. Among various inflammatory diseases, IL-37 has been shown to regulate inflammatory development by acting on various immune cells such as neutrophils, macrophages (Mϕ), dendritic cells (DCs), T cells and intestinal epithelial cells. This review summarizes the biological role of IL-37, and its immunoregulatory effects on the immune cells, especially anti-inflammatory function in both human and experimental models of IBD.

IFN-γ and IL-17A regulate intestinal crypt production of CXCL10 in the healthy and inflamed colon

During intestinal inflammation, immature cells within the intestinal crypt are called upon to replenish lost epithelial cell populations, promote tissue regeneration, and restore barrier integrity. Inflammatory mediators including T_H1/T_H17-associated cytokines influence tissue health and regenerative processes, yet how these cytokines directly influence the colon crypt epithelium and whether the crypt remains responsive to these cytokines during active damage and repair, remain unclear. Here, using laser-capture microdissection and primary colon organoid culture, we show that the cytokine milieu regulates the ability of the colonic crypt epithelium to participate in proinflammatory signaling. IFN-γ induces the T_H1-recruiting, proinflammatory chemokine CXCL10/IP10 in primary murine intestinal crypt epithelium. CXCL10 was also induced in colonic organoids derived from mice with active, experimentally induced colitis, suggesting that the crypt can actively secrete CXCL10 in select cytokine environments during colitis. Colon expression of cxcl10 further increased during infectious and noninfectious colitis in Il17a^-/- mice, demonstrating that IL-17A exerts a negative effect on CXCL10 in vivo. Furthermore, IL-17A directly antagonized CXCL10 production in ex vivo organoid cultures derived from healthy murine colons. Interestingly, direct antagonism of CXCL10 was not observed in organoids derived from colitic mouse colons bearing active lesions. These data, highlighting the complex interplay between the cytokine milieu and crypt epithelia, demonstrate proinflammatory chemokines can be induced within the colonic crypt and suggest the crypt remains responsive to cytokine modulation during inflammation.NEW & NOTEWORTHY Upon damage, the intestinal epithelium regenerates to restore barrier function. Here we observe that the local colonic cytokine milieu controls the production of procolitic chemokines within the crypt base and colon crypts remain responsive to cytokines during inflammation. IFN-γ promotes, while IL-17 antagonizes, CXCL10 production in healthy colonic crypts, while responses to cytokines differ in inflamed colon epithelium. These data reveal novel insight into colon crypt responses and inflammation-relevant alterations in signaling.

Chemokines and Chemokine Receptors as Therapeutic Targets in Inflammatory Bowel Disease; Pitfalls and Promise

The principal targets for anti-chemokine therapy in inflammatory bowel disease (IBD) have been the receptors CCR9 and CXCR3 and their respective ligands CCL25 and CXCL10. More recently CCR6 and its ligand CCL20 have also received attention, the expression of the latter in enterocytes being manipulated through Smad7 signalling. These pathways, selected based on their fundamental role in regulating mucosal immunity, have led to the development of several therapeutic candidates that have been tested in early phase clinical trials with variable clinical efficacy. In this article, we appraise the status of chemokine-directed therapy in IBD, review recent developments, and nominate future areas for therapeutic focus.

An Atlas of Genetic Variation Linking Pathogen-Induced Cellular Traits to Human Disease

Pathogens have been a strong driving force for natural selection. Therefore, understanding how human genetic differences impact infection-related cellular traits can mechanistically link genetic variation to disease susceptibility. Here we report the Hi-HOST Phenome Project (H2P2): a catalog of cellular genome-wide association studies (GWAS) comprising 79 infection-related phenotypes in response to 8 pathogens in 528 lymphoblastoid cell lines. Seventeen loci surpass genome-wide significance for infection-associated phenotypes ranging from pathogen replication to cytokine production. We combined H2P2 with clinical association data from patients to identify a SNP near CXCL10 as a risk factor for inflammatory bowel disease. A SNP in the transcriptional repressor ZBTB20 demonstrated pleiotropy, likely through suppression of multiple target genes, and was associated with viral hepatitis. These data are available on a web portal to facilitate interpreting human genome variation through the lens of cell biology and should serve as a rich resource for the research community.

PD-1 deficiency protects experimental colitis via alteration of gut microbiota

Programmed cell death-1 (PD-1) is a coinhibitory molecule and plays a pivotal role in immune regulation. Here, we demonstrate a role for PD-1 in pathogenesis of inflammatory bowel disease (IBD). Wild-type (WT) mice had severe wasting disease during experimentally induced colitis, while mice deficient for PD-1 (PD-1^−/−) did not develop colon inflammation. Interestingly, PD-1^−/− mice cohoused with WT mice became susceptible to colitis, suggesting that resistance of PD-1^−/− mice to colitis is dependent on their gut microbiota. 16S rRNA gene-pyrosequencing analysis showed that PD-1^−/− mice had altered composition of gut microbiota with significant reduction in Rikenellaceae family. These altered colon bacteria of PD-1^−/− mice induced less amount of inflammatory mediators from colon epithelial cells, including interleukin (IL)-6, and inflammatory chemokines. Taken together, our study indicates that PD-1 expression is involved in the resistance to experimental colitis through altered bacterial communities of colon.

IP-10 Promotes Blood-Brain Barrier Damage by Inducing Tumor Necrosis Factor Alpha Production in Japanese Encephalitis

Japanese encephalitis is a neuropathological disorder caused by Japanese encephalitis virus (JEV), which is characterized by severe pathological neuroinflammation and damage to the blood-brain barrier (BBB). Inflammatory cytokines/chemokines can regulate the expression of tight junction (TJ) proteins and are believed to be a leading cause of BBB disruption, but the specific mechanisms remain unclear. IP-10 is the most abundant chemokine produced in the early stage of JEV infection, but its role in BBB disruption is unknown. The administration of IP-10-neutralizing antibody ameliorated the decrease in TJ proteins and restored BBB integrity in JEV-infected mice. In vitro study showed IP-10 and JEV treatment did not directly alter the permeability of the monolayers of endothelial cells. However, IP-10 treatment promoted tumor necrosis factor alpha (TNF-α) production and IP-10-neutralizing antibody significantly reduced the production of TNF-α. Thus, TNF-α could be a downstream cytokine of IP-10, which decreased TJ proteins and damaged BBB integrity. Further study indicated that JEV infection can stimulate upregulation of the IP-10 receptor CXCR3 on astrocytes, resulting in TNF-α production through the JNK-c-Jun signaling pathway. Consequently, TNF-α affected the expression and cellular distribution of TJs in brain microvascular endothelial cells and led to BBB damage during JEV infection. Regarding regulation of the BBB, the IP-10/TNF-α cytokine axis could be considered a potential target for the development of novel therapeutics in BBB-related neurological diseases.

The CXC Chemokine Receptor 3 Inhibits Autoimmune Cholangitis via CD8+ T Cells but Promotes Colitis via CD4+ T Cells

CXC chemokine receptor 3 (CXCR3), a receptor for the C-X-C motif chemokines (CXCL) CXCL9, CXCL10, and CXCL11, which not only plays a role in chemotaxis but also regulates differentiation and development of memory and effector T cell populations. Herein, we explored the function of CXCR3 in the modulation of different organ-specific autoimmune diseases in interleukin (IL)-2 receptor deficiency (CD25^-/-) mice, a murine model for both cholangitis and colitis. We observed higher levels of CXCL9 and CXCL10 in the liver and colon and higher expression of CXCR3 on T cells of the CD25^-/- mice compared with control animals. Deletion of CXCR3 resulted in enhanced liver inflammation but alleviated colitis. These changes in liver and colon pathology after CXCR3 deletion were associated with increased numbers of hepatic CD4⁺ and CD8⁺ T cells, in particular effector memory CD8⁺ T cells, as well as decreased T cells in mesenteric lymph nodes and colon lamina propria. In addition, increased interferon-γ response and decreased IL-17A response was observed in both liver and colon after CXCR3 deletion. CXCR3 modulated the functions of T cells involved in different autoimmune diseases, whereas the consequence of such modulation was organ-specific regarding to their effects on disease severity. Our findings emphasize the importance of extra caution in immunotherapy for organ-specific autoimmune diseases, as therapeutic interventions aiming at a target such as CXCR3 for certain disease could result in adverse effects in an unrelated organ.

Novel Insights into the Mechanisms of Gut Homing and Antiadhesion Therapies in Inflammatory Bowel Diseases

Therapeutic compounds interfering with T cell trafficking are a new column of inflammatory bowel disease (IBD) treatment. Currently, the anti-α4β7 integrin antibody vedolizumab is successfully used in the clinic and further drugs are likely to follow. Despite these clinical advances, the precise mechanistic background of their action is only gradually elucidated and still a matter of intensive research. Only recently, advances made with the help of new in vivo models and human studies have contributed to shape our concept of T cell trafficking in IBD by deciphering some important and so far unanswered questions. At the same time, basic and clinical data have generated new issues to be addressed on the way toward a clear perception of trafficking mechanisms and toward elucidation of the action of compounds interfering with this process. In this review, we will give a comprehensive outline of all components of T cell trafficking in regard to IBD before discussing the current knowledge concerning targeted interference with integrins in this complex network. Moreover, we will summarize remaining ambiguity and give an outlook on potential future targets.

Antibody Neutralization of CXCL10 in Vivo Is Dependent on Binding to Free and Not Endothelial-bound Chemokine: IMPLICATIONS FOR THE DESIGN OF A NEW GENERATION OF ANTI-CHEMOKINE THERAPEUTIC ANTIBODIES

To improve our understanding of properties that confer successful inhibition of chemokines in vivo, we analyzed anti-murine CXCL10 monoclonal antibodies (mAb) having different characteristics. 1B6 displayed potent inhibition of cell recruitment in vitro with an IC50 of 0.5 nm but demonstrated little efficacy in various animal models of human disease. On the contrary, 1F11 showed efficacy in several models of inflammation yet was less potent at inhibiting chemotaxis in vitro with an IC50 of 21 nm Furthermore, we observed that 1B6 displayed a rapid dose-dependent clearance (t½ 10-60 h) in contrast to 1F11, which presented a dose-proportional pharmacokinetic profile and a half-life of 12 days. Moreover, 1B6 recognized glycosaminoglycan (GAG)-bound CXCL10, resulting in target-mediated clearance, which was corroborated using CXCL10-deficient mice. In contrast to 1B6, 1F11 inhibited the interaction of CXCL10 with GAGs, did not recognize GAG-bound CXCL10, and did not display target-mediated drug disposition. Confirming previous animal studies, 1B6 was poor at reversing glycemia in a model of type 1 diabetes, whereas 1F11 induced early and prolonged control of diabetes. Furthermore, when using 1A4, a subsequently generated anti-mCXCL10 mAb that shares the property with 1F11 of being unable to recognize CXCL10 immobilized on GAG, we observed a similar superior control of diabetes as compared with 1B6. We therefore concluded that targeting chemokines with antibodies such as 1B6 that recognize the more abundant GAG-bound form of the chemokine may not be the optimal strategy to achieve disease control.

Proposed therapies in primary biliary cholangitis

Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is a model autoimmune disease with chronic cholestasis characterized by the hallmark of anti-mitochondrial antibodies and treated with ursodeoxycholic acid (UDCA). However, approximately 20-40% of patients incompletely respond to UDCA and have an increased risk of disease progression. Although there have been significant advances in the immunobiology of PBC, these have yet to be translated into newer therapeutic modalities. Current approaches to controlling the immune response include broad immunosuppression with corticosteroids as well as targeted therapies directed against T and B cells. In contrast, ameliorating cholestasis is the focus of other therapies in development, including obeticholic acid. In this article the authors will discuss ongoing clinical trials and, in particular, the rationale for choosing agents that may effectively target the aberrant immune response.

Serum Cytokine Profiles in Children with Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that can be diagnosed at any age. There are two major patient groups based on diagnosis of this disease, before or after the age of 20 (juvenile/adolescent or adult), with disease progression in adults usually milder than in juvenile CD patients. Immune mechanisms have been suggested to play an important role in CD pathogenesis, with cytokines governing the development of the immune response. Upregulation of inflammatory cytokines in serum of juvenile and adult CD patients has been documented; still little is known about age-dependent differences in serum cytokine profiles of CD patients. We applied multiplex technology to analyze serum levels of 12 cytokines in juveniles and adults. We show that during the acute stage of the disease all CD patients have high serum levels of CXCL10, which remains upregulated during remission. Increased serum levels of TNF-α and IL-6 during the acute stage was characteristic of juvenile CD patients, whereas adult CD patients had upregulated levels of GM-CSF and IFN-γ. Taken together, these results demonstrate age-dependent differences in cytokine profiles, which may affect the pathogenesis of CD in patients at different ages of disease onset.

Eldelumab [Anti-IP-10] Induction Therapy for Ulcerative Colitis: A Randomised, Placebo-Controlled, Phase 2b Study

BACKGROUND AND AIMS

Interferon-γ-inducible protein-10 [IP-10] mediates immune cell trafficking from the circulation to the inflamed colon and decreases gut epithelial cell survival. IP-10 expression is increased in patients with ulcerative colitis [UC]. We report efficacy and safety results from a dose-ranging induction study of eldelumab, a fully human monoclonal antibody to IP-10, in moderately to severely active UC.

METHODS

A total of 252 adults with UC [Mayo score ≥ 6 and endoscopic subscore ≥ 2] were randomised 1:1:1 to placebo or eldelumab 15 or 25 mg/kg administered intravenously on Days 1 and 8 and every other week thereafter. The primary endpoint was clinical remission [Mayo score ≤ 2; no individual subscale score > 1] at Week 11. Key secondary endpoints included Mayo score clinical response and mucosal healing at Week 11.

RESULTS

Neither eldelumab 15 or 25 mg/kg resulted in significant increases vs placebo in the proportion of patients achieving Week 11 clinical remission. Remission and response rates were 17.6% and 47.1% with eldelumab 25mg/kg, 13.1% and 44.0% with eldelumab 15mg/kg, and 9.6% and 31.3% with placebo. Clinical remission and response rates were higher in anti-tumour necrosis factor [TNF]-naïve patients treated with eldelumab compared with placebo. Eldelumab treatment was well tolerated and no immunogenicity was observed.

CONCLUSIONS

The primary endpoint was not achieved with induction treatment with eldelumab 15 or 25 mg/kg in patients with UC. Trends towards clinical remission and response were observed in the overall population and were more pronounced in anti-TNF naïve patients. Eldelumab safety signals were consistent with those reported previously [ClinicalTrials.gov number, NCT01294410].

Integrating analysis reveals microRNA-mediated pathway crosstalk among Crohn's disease, ulcerative colitis and colorectal cancer

Inflammatory bowel disease (IBD), which can increase the risk of colorectal cancer (CRC), includes two primary subtypes, ulcerative colitis (UC) and Crohn's disease (CD). Although several individual genes involved in inflammation or cancer characterization have been identified, it is still difficult to elucidate functional relationship details between the molecules underlying pathogenesis at the system level. The global effect of miRNAs on genes or their involved functions is also poorly understood. We first integrated genome-wide gene expression profiles and biological pathway information to explore the underlying associations among UC, CD and CRC at the function and gene level. After identifying the pathways regulated by miRNAs, a global map of miRNA-mediated pathway crosstalk shared by the three diseases was further constructed to vertically explain the links of three level alterations. The three types of diseases have close associations with each other at the levels of function, gene and miRNA regulation. Several key biological pathways are involved in the three diseases, related to the immune system and inflammation, metabolism, or cell proliferation and apoptosis etc. Moreover, miRNAs exhibit dominant effects on multiple pathways. It is worth noting that UC shows relatively close associations with CD and CRC at the three levels. Finally, the miRNAs could mediate the crosstalk within or between pathways. For example, hsa-miR-125b, hsa-miR-335 and hsa-miR-155 mediated the crosstalk between three metabolic pathways. The crosstalk within the Toll-like receptor signaling pathway could be mediated by hsa-miR-124, hsa-miR-146a and hsa-mir-221/222. Our results make sense for the prevention and treatment of intestinal-related chronic inflammation or cancer.

Noncanonical Effects of IRF9 in Intestinal Inflammation: More than Type I and Type III Interferons

The interferon (IFN)-stimulated gene factor 3 (ISGF3) transcription factor with its Stat1, Stat2, and interferon regulatory factor 9 (IRF9) subunits is employed for transcriptional responses downstream of receptors for type I interferons (IFN-I) that include IFN-α and IFN-β and type III interferons (IFN-III), also called IFN-λ. Here, we show in a murine model of dextran sodium sulfate (DSS)-induced colitis that IRF9 deficiency protects animals, whereas the combined loss of IFN-I and IFN-III receptors worsens their condition. We explain the different phenotypes by demonstrating a function of IRF9 in a noncanonical transcriptional complex with Stat1, apart from IFN-I and IFN-III signaling. Together, Stat1 and IRF9 produce a proinflammatory activity that overrides the benefits of the IFN-III response on intestinal epithelial cells. Our results further suggest that the CXCL10 chemokine gene is an important mediator of this proinflammatory activity. We thus establish IFN-λ as a potentially anticolitogenic cytokine and propose an important role for IRF9 as a component of noncanonical Stat complexes in the development of colitis.

CXCL10 is critical for the progression and maintenance of depigmentation in a mouse model of vitiligo

Vitiligo is an autoimmune disease of the skin that results in disfiguring white spots. There are no U.S. Food and Drug Administration-approved treatments for vitiligo, and most off-label treatments yield unsatisfactory results. Vitiligo patients have increased numbers of autoreactive, melanocyte-specific CD8(+) T cells in the skin and blood, which are directly responsible for melanocyte destruction. We report that gene expression in lesional skin from vitiligo patients revealed an interferon-γ (IFN-γ)-specific signature, including the chemokine CXCL10. CXCL10 was elevated in both vitiligo patient skin and serum, and CXCR3, its receptor, was expressed on pathogenic T cells. To address the function of CXCL10 in vitiligo, we used a mouse model of disease that also exhibited an IFN-γ-specific gene signature, expression of CXCL10 in the skin, and up-regulation of CXCR3 on antigen-specific T cells. Mice that received Cxcr3(-/-) T cells developed minimal depigmentation, as did mice lacking Cxcl10 or treated with CXCL10-neutralizing antibody. CXCL9 promoted autoreactive T cell global recruitment to the skin but not effector function, whereas CXCL10 was required for effector function and localization within the skin. Surprisingly, CXCL10 neutralization in mice with established, widespread depigmentation induces reversal of disease, evidenced by repigmentation. These data identify a critical role for CXCL10 in both the progression and maintenance of vitiligo and thereby support inhibiting CXCL10 as a targeted treatment strategy.

NOD2 regulates CXCR3-dependent CD8+ T cell accumulation in intestinal tissues with acute injury

Polymorphisms in NOD2 confer risk for Crohn's disease, characterized by intestinal inflammation. How NOD2 regulates both inflammatory and regulatory intestinal T cells, which are critical to intestinal immune homeostasis, is not well understood. Anti-CD3 mAb administration is used as therapy in human autoimmune diseases, as well as a model of transient intestinal injury. The stages of T cell activation, intestinal injury, and subsequent T tolerance are dependent on migration of T cells into the small intestinal (SI) lamina propria. Upon anti-CD3 mAb treatment of mice, we found that NOD2 was required for optimal small intestinal IL-10 production, in particular from CD8(+) T cells. This requirement was associated with a critical role for NOD2 in SI CD8(+) T cell accumulation and induction of the CXCR3 ligands CXCL9 and CXCL10, which regulate T cell migration. NOD2 was required in both the hematopoietic and nonhematopoietic compartments for optimal expression of CXCR3 ligands in intestinal tissues. NOD2 synergized with IFN-γ to induce CXCL9 and CXCL10 secretion in dendritic cells, macrophages, and intestinal stromal cells in vitro. Consistent with the in vitro studies, during anti-CD3 mAb treatment in vivo, CXCR3 blockade, CD8(+) T cell depletion, or IFN-γ neutralization each inhibited SI CD8(+) T cell recruitment, and reduced chemokine expression and IL-10 expression. Thus, NOD2 synergizes with IFN-γ to promote CXCL9 and CXCL10 expression, thereby amplifying CXCR3-dependent SI CD8(+) T cell migration during T cell activation, which, in turn, contributes to induction of both inflammatory and regulatory T cell outcomes in the intestinal environment.

Anti-IP-10 antibody (BMS-936557) for ulcerative colitis: a phase II randomised study

OBJECTIVE

Interferon-γ-inducible protein-10 (IP-10 or CXCL10) plays a role in inflammatory cell migration and epithelial cell survival and migration. It is expressed in higher levels in the colonic tissue and plasma of patients with ulcerative colitis (UC). This phase II study assessed the efficacy and safety of BMS-936557, a fully human, monoclonal antibody to IP-10, in the treatment of moderately-to-severely active UC.

DESIGN

In this 8-week, phase II, double-blind, multicentre, randomised study, patients with active UC received placebo or BMS-936557 (10 mg/kg) intravenously every other week. The primary endpoint was the rate of clinical response at Day 57; clinical remission and mucosal healing rates were secondary endpoints. Post hoc analyses evaluated the drug exposure-response relationship and histological improvement.

RESULTS

109 patients were included (BMS-936557: n=55; placebo: n=54). Prespecified primary and secondary endpoints were not met; clinical response rate at Day 57 was 52.7% versus 35.2% for BMS-936557 versus placebo (p=0.083), and clinical remission and mucosal healing rates were 18.2% versus 16.7% (p=1.00) and 41.8% versus 35.2% (p=0.556), respectively. However, higher BMS-936557 steady-state trough concentration (Cminss) was associated with increased clinical response (87.5% vs 37.0% (p<0.001) for patients with Cminss 108-235 μg/ml vs placebo) and histological improvements (73.0% vs 41.0%; p=0.004). Infections occurred in 7 (12.7%) BMS-936557-treated patients and 3 (5.8%) placebo-treated patients. 2 (3.6%) BMS-936557 patients discontinued due to adverse events.

CONCLUSIONS

Anti-IP-10 antibody, BMS-936557, is a potentially effective therapy for moderately-to-severely active UC. Higher drug exposure correlated with increasing clinical response and histological improvement. Further dose-response studies are warranted.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT00656890.

CXCR3 axis in patients with primary biliary cirrhosis: a possible novel mechanism of the effect of ursodeoxycholic acid

The CXC chemokines, monokine induced by interferon (IFN)-gamma (MIG) (CXCL9), IFN-gamma-induced protein 10 (IP-10) (CXCL10) and IFN-inducible T cell alpha chemoattractant (I-TAC) (CXCL11), are known to attract CXCR3- (CXCR3A and CXCR3B) T lymphocytes. We investigated MIG, IP-10 and I-TAC mRNAs expression by semi-quantitative multiplex reverse transcription-polymerase chain reaction (RT-PCR) in liver biopsies obtained from patients with a first diagnosis of primary biliary cirrhosis [(PBC) = 20] compared to patients with normal liver biopsy [normal controls (NCs) = 20]. Chemokine production was assessed by enzyme-linked immunosorbent assay (ELISA) in serum. Measurements were repeated 6 months after ursodeoxycholic acid (UDCA) treatment in PBC patients. CXCR3A and CXCR3B mRNAs expression was examined in immunomagnetically sorted CD3(+) peripheral blood lymphocytes (PBL) pre- and post-treatment by RT-PCR. Flow cytometry was used to evaluate the expression of CXCR3(+) PBLs of NCs and PBC patients. A marked mRNA expression of MIG and IP-10 was found in PBC patients. I-TAC mRNA was not detected. In serum of PBC patients there was a significant increase of MIG and IP-10 compared to NCs. Interestingly, there was a significant reduction of these proteins in patients' serum after UDCA treatment. I-TAC was not statistically different between groups. CXCR3A mRNA expression was found in PBLs from PBC patients as well as in NCs. CXCR3B mRNA was expressed in four of 20 (19%) NCs and 20 of 20 PBC patients. Flow cytometry revealed a significantly lower CXCR3 expression in NCs (13·5%) than in PBC (37·2%), which was reduced (28·1%, P < 0·01) after UDCA administration. These data suggest a possible role for CXCR3-binding chemokines and their receptor in the aetiopathogenetic recruitment of lymphocytes in PBC and a new mechanism of action for UDCA.

Lactocepin as a protective microbial structure in the context of IBD

Probiotics have been shown to exert beneficial effects in the context of different diseases including inflammatory bowel diseases (IBD). However, clinical use of probiotics is hampered by lack of understanding of the protective mechanisms and by safety concerns regarding the application of high numbers of live bacteria in patients. The identification of protective microbial structure-function relationships might enable to overcome these restraints and might lead to innovative therapies using the isolated active microbial structures. In our study, we aimed to characterize the protective mechanisms of VSL#3, a clinically relevant probiotic mixture in IBD. We found Lactobacillus casei/paracasei-produced lactocepin to selectively degrade pro-inflammatory chemokines, resulting in reduced immune cell infiltration and reduced inflammation in experimental IBD models. As immune cell recruitment is a major proinflammatory mechanism our findings suggest that lactocepin might be of broad therapeutic relevance in an array of inflammatory diseases like IBD, allergic skin inflammation and psoriasis.

Enhanced expression of CXCL10 in inflammatory bowel disease: potential role of mucosal Toll-like receptor 3 stimulation

BACKGROUND

We explored the gene expression in colonic biopsies of active and inactive inflammatory bowel disease (IBD) in an extensive material of ulcerative colitis (UC) and Crohn's disease (CD). The chemokine CXCL10 and its receptor CXCR3 were among the upregulated genes. This study examined the expression of CXCL10 and the mechanisms for its release in patients with UC or CD and in intestinal epithelial cell (IEC) lines.

METHODS

A microarray gene expression analysis was done on colonic biopsies (n = 133) from patients with IBD. Biopsies were studied with immunohistochemistry for CXCL10 and CXCR3 expression. Mechanisms for CXCL10 release in peripheral blood mononuclear cells (PBMCs) and in the colonic epithelial cell lines HT-29 and SW620 were studied upon pattern recognition receptor (PRR) stimulation.

RESULTS

CXCL10 and CXCR3 mRNA abundances were increased in biopsies from active UC and CD compared to inactive disease and controls. CXCL10 was mainly localized to mucosal epithelial cells, with increased immunostaining in active IBD. CXCR3-positive cells were scattered in the lamina propria. CXCL10 was secreted from the colonic epithelial cell lines in response to the Toll-like receptor 3 (TLR3) ligand polyinosinic: polycytidylic acid (poly(I:C)). This ligand also induced a marked release of CXCL10 in PBMCs from IBD patients and controls.

CONCLUSIONS

We identified CXCL10 and CXCR3 as upregulated genes in colonic mucosa in active IBD. The TLR3-ligand poly(I:C) markedly increased release of CXCL10 in colonic epithelial cell lines, suggesting a TLR3-mediated CXCL10 release from mucosal epithelial cells in IBD patients.

Alternative medicines as emerging therapies for inflammatory bowel diseases

Inflammatory bowel disease (IBD) can be divided into two major categories, ulcerative colitis (UC) and Crohn disease (CD). While the main cause(s) of IBD remain unknown, a number of interventional and preventive strategies have been proposed for use against CD and UC. Many reports have focused on the use of alternative natural medicines as potential therapeutic interventions in IBD patients with minimal side effects. While the use of alternative medicines may be effective in IBD patients that are refractory to corticosteroids or thiopurins, alternative treatment strategies are limited and require extensive clinical testing before being optimized for use in patients.

Role of resveratrol-induced CD11b(+) Gr-1(+) myeloid derived suppressor cells (MDSCs) in the reduction of CXCR3(+) T cells and amelioration of chronic colitis in IL-10(-/-) mice

Resveratrol, a naturally occurring polyphenol has received significant attention as a potent anti-inflammatory agent. Inflammatory bowel disease (IBD) is a chronic intestinal inflammation caused by hyperactivated effector immune cells that produce proinflammatory cytokines. Myeloid derived suppressor cells (MDSCs) are a heterogeneous population characterized by the co-expression of CD11b(+) and Gr-1(+) and have long been known for their immunosuppressive function. We report that resveratrol effectively attenuated overall clinical scores as well as various pathological markers of colitis in IL-10(-/-) mice by down regulating Th1 responses. Resveratrol lessened the colitis-associated decrease in body weight and increased levels of serum amyloid A (SAA), CXCL10 and colon TNF-α, IL-6, RANTES, IL-12 and IL-1β concentrations. After resveratrol treatment, the percentage of CXCR3 expressing T cells was decreased in the spleen, mesenteric lymph nodes (MLN), and intestinal lamina propria (LP). However, the percentage and absolute numbers of CD11b(+) and Gr-1(+)cells in the lamina propria (LP) and spleen were increased after resveratrol treatment as compared with the vehicle treatment. Co-culture of resveratrol-induced CD11b(+) Gr-1(+) cells with T cells, attenuated T cell proliferation, and most importantly reduced IFN-γ and GM-CSF production by LP derived T cells from vehicle treated IL-10(-/-) mice with chronic colitis. The current study suggests that administration of resveratrol into IL-10(-/-) mice induces immunosuppressive CD11b(+) Gr-1(+) MDSCs in the colon, which correlates with reversal of established chronic colitis, and down regulation of mucosal and systemic CXCR3(+) expressing effector T cells as well as inflammatory cytokines in the colon. The induction of immunosuppressive CD11b(+) Gr-1(+) cells by resveratrol during colitis is unique, and suggests an as-yet-unidentified mode of anti-inflammatory action of this plant polyphenol.

Shining a light on intestinal traffic

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is associated with enhanced leukocyte infiltration to the gut, which is directly linked to the clinical aspects of these disorders. Thus, leukocyte trafficking is a major target for IBD therapy. Past and emerging techniques to study leukocyte trafficking both in vitro and in vivo have expanded our knowledge of the leukocyte migration process and the role of inhibitors. Various strategies have been employed to target chemokine- and integrin-ligand interactions within the multistep adhesion cascade and the S1P/S1PR1 axis in leukocyte migration. Though there is an abundance of preclinical data demonstrating efficacy of leukocyte trafficking inhibitors, many have yet to be confirmed in clinical studies. Vigilance for toxicity and further research is required into this complex and emerging area of IBD therapy.

Atherosclerotic Plaque Stability Is Affected by the Chemokine CXCL10 in Both Mice and Humans

Background. The chemokine CXCL10 is specifically upregulated during experimental development of plaque with an unstable phenotype. In this study we evaluated the functional consequences of these findings in mice and humans. Methods and Results. In ApoE^−/− mice, we induced unstable plaque with using a flow-altering device around the carotid artery. From week 1 to 4, mice were injected with a neutralizing CXCL10 antibody. After 9 weeks, CXCL10 inhibition resulted in a more stable plaque phenotype: collagen increased by 58% (P = 0.002), smooth muscle cell content increased 2-fold (P = 0.03), while macrophage MHC class II expression decreased by 50% (P = 0.005). Also, the size of necrotic cores decreased by 41% (P = 0.01). In 106 human carotid endarterectomy specimens we found that increasing concentrations of CXCL10 strongly associate with an increase in atheromatous plaque phenotype (ANOVA, P = 0.003), with high macrophage, low smooth muscle cell, and low collagen content. Conclusions. In the present study we showed that CXCL10 is associated with the development of vulnerable plaque in human and mice. We conclude that CXCL10 might provide a new lead towards plaque-stabilizing therapy.

Targeted intestinal epithelial deletion of the chemokine receptor CXCR4 reveals important roles for extracellular-regulated kinase-1/2 in restitution

Barrier defects and/or alterations in the ability of the gut epithelium to repair itself are critical etiological mechanisms of gastrointestinal disease. Our ongoing studies indicate that the chemokine receptor CXCR4 and its cognate ligand CXCL12 regulate intestinal-epithelial barrier maturation and restitution in cell culture models. Gene-deficient mice lacking CXCR4 expression specifically by the cells of the intestinal epithelium were used to test the hypothesis that CXCR4 regulates mucosal barrier integrity in vivo. Epithelial expression of CXCR4 was assessed by RT-PCR, Southern blot, immunoblot and immunohistochemistry. In vivo wounding assays were performed by addition of 3% dextran sodium sulfate (DSS) in drinking water for 5 days. Intestinal damage and DAI scores were assessed by histological examination. Extracellular-regulated kinase (ERK) phosphorylation was assessed in vivo by immunoblot and immunofluorescence. CXCR4 knockdown cells were established using a lentiviral approach and ERK phosphorylation was assessed. Consistent with targeted roles in restitution, epithelium from patients with inflammatory bowel disease indicated that CXCR4 and CXCL12 expression was stable throughout the human colonic epithelium. Conditional CXCR4-deficient mice developed normally, with little phenotypic differences in epithelial morphology, proliferation or migration. Re-epithelialization was absent in CXCR4 conditional knockout mice following acute DSS-induced inflammation. In contrast, heterozygous CXCR4-depleted mice displayed significant improvement in epithelial ulcer healing in acute and chronic inflammation. Mucosal injury repair was correlated with ERK1/2 activity and localization along the crypt-villus axis, with heterozygous mice characterized by increased ERK1/2 activation. Lentiviral depletion of CXCR4 in IEC-6 cells similarly altered ERK1/2 activity and prevented chemokine-stimulated migration. Taken together, these data indicate that chemokine receptors participate in epithelial barrier responses through coordination of the ERK1/2 signaling pathway.

CXCR3 in T cell function

CXCR3 is a chemokine receptor that is highly expressed on effector T cells and plays an important role in T cell trafficking and function. CXCR3 is rapidly induced on naïve cells following activation and preferentially remains highly expressed on Th1-type CD4(+) T cells and effector CD8(+) T cells. CXCR3 is activated by three interferon-inducible ligands CXCL9 (MIG), CXCL10 (IP-10) and CXCL11 (I-TAC). Early studies demonstrated a role for CXCR3 in the trafficking of Th1 and CD8 T cells to peripheral sites of Th1-type inflammation and the establishment of a Th1 amplification loop mediated by IFNγ and the IFNγ-inducible CXCR3 ligands. More recent studies have also suggested that CXCR3 plays a role in the migration of T cells in the microenvironment of the peripheral tissue and lymphoid compartment, facilitating the interaction of T cells with antigen presenting cells leading to the generation of effector and memory cells.

CXCR3 ligands: redundant, collaborative and antagonistic functions

CXCR3 is a chemokine receptor that is rapidly induced on naïve T cells following activation, and preferentially remains highly expressed on type-1 helper (Th1)-type CD4(+) T cells, effector CD8(+) T cells and innate-type lymphocytes, such as natural killer (NK) and NKT cells. CXCR3 is activated by three interferon (IFN)-γ-inducible ligands CXCL9 (monokine induced by gamma-interferon), CXCL10 (interferon-induced protein-10) and CXCL11 (interferon-inducible T-cell alpha chemoattractant). Although some studies have revealed that these ligands have redundant functions in vivo, other studies have demonstrated that the three CXCR3 ligands can also collaborate and even compete with each other. Differential regulation of the three ligands at specific times in defined anatomically restricted locations in vivo likely participates in the fine control of T-cell trafficking over the course of an immune response. Among the differences in regulation, CXCL10 is induced by a variety of innate stimuli that induce IFN-α/β as well as the adaptive immune cell cytokine IFN-γ, whereas CXCL9 induction is restricted to IFN-γ. In this review, we will discuss how the balance, timing and pattern of CXCR3 ligand expression appears to regulate the generation of effector T cells in the lymphoid compartment and subsequent migration into peripheral sites of Th1-type inflammation in which the CXCR3 ligands also then regulate the interactions and migratory behavior of effector T cells in an inflamed peripheral tissue.