CXCL10-producing mucosal CD4+ T cells, NK cells, and NKT cells are associated with chronic colitis in IL-10(-/-) mice, which can be abrogated by anti-CXCL10 antibody inhibition

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.

The CXCL10/CXCR3 Axis Promotes Disease Pathogenesis in Mice upon CVA2 Infection

Coxsackievirus A2 (CVA2) is an emerging pathogen that results in hand-foot-and-mouth disease (HFMD) outbreaks. Systemic inflammatory response and central nervous system inflammation are the main pathological features of fatal HFMD. However, the immunopathogenesis of CVA2 infection is poorly understood. We first detected the transcriptional levels of 81 inflammation-related genes in neonatal mice with CVA2 infection. Remarkably, CVA2 induced higher expression of chemokine (C-X-C motif) ligand 10 (CXCL10) in multiple organs and tissues. CXCL10 acts through its cognate receptor chemokine (C-X-C motif) receptor 3 (CXCR3) and regulates immune responses. CXCL10/CXCR3 activation contributes to the pathogenesis of many inflammatory diseases. Next, we found CXCL10 and CXCR3 expression to be significantly elevated in the organs and tissues from CVA2-infected mice at 5 days postinfection (dpi) using immunohistochemistry (IHC). To further explore the role of CXCL10/CXCR3 in CVA2 pathogenesis, an anti-CXCR3 neutralizing antibody (αCXCR3) or IgG isotype control antibody was used to treat CVA2-infected mice on the same day as infection and every 24 h until 5 dpi. Our results showed that αCXCR3 therapy relieved the clinical manifestations and pathological damage and improved the survival rate of CVA2-infected mice. Additionally, αCXCR3 treatment reduced viral loads and reversed the proinflammatory cytokine (interleukin 6 [IL-6], tumor necrosis factor alpha [TNF-α], and IL-1β) expression, apoptosis, and inflammatory cell infiltration induced by CVA2. Collectively, our study presents evidence for the involvement of the CXCL10/CXCR3 axis in CVA2 pathogenesis. The activation of CXCL10/CXCR3 contributes to CVA2 pathogenesis by inducing apoptosis, proinflammatory cytokine expression, and inflammatory cell infiltration, which can be reversed by αCXCR3 therapy. This study provides new insight into the pathogenesis of HFMD, which has an important guiding significance for the treatment of HFMD. IMPORTANCE Systemic inflammatory response and central nervous system inflammation are the main pathological features of fatal HFMD cases. We detected the expression of 81 inflammation-related genes and found higher expression of CXCL10 in CVA2-infected mice. Next, we confirmed CXCL10/CXCR3 activation using immunohistochemistry and found that anti-CXCR3 neutralizing antibody (αCXCR3) therapy could relieve the clinical manifestations and pathological damage and improve the survival rate of CVA2-infected mice. Additionally, αCXCR3 treatment reduced viral loads and reversed the proinflammatory cytokine (IL-6, TNF-α, and IL-1β) expression, apoptosis, and inflammatory cell infiltration induced by CVA2. Collectively, our study presents the first evidence for the involvement of the CXCL10/CXCR3 axis in CVA2 pathogenesis. The activation of CXCL10/CXCR3 contributes to CVA2 pathogenesis via inducing apoptosis, proinflammatory cytokine expression, and inflammatory cell infiltration, which can be reversed by αCXCR3 therapy. This study provides new insight into the pathogenesis of HFMD, which has an important guiding significance for the treatment of HFMD.

High Fat Diet-Induced CD8+ T Cells in Adipose Tissue Mediate Macrophages to Sustain Low-Grade Chronic Inflammation

Obesity in the United States and worldwide reached epidemic proportions within the last 20 years. Obesity is a very powerful health determinant or indicator that facilitates the development and progression of several metabolic diseases, insulin resistance, and low-grade chronic inflammation. Low-grade chronic inflammation in adipose tissue (AT) is marked by the accumulation of T cells, macrophages, and other immune cells and increased production of proinflammatory cytokines. During the onset of obesity but before the influx of macrophages, the AT is infiltrated by T cells that are strongly implicated in the initiation of obesity-associated inflammation. In comparing mice fed a high-fat diet (HFD) with those fed a normal diet (ND), we observed in HFD epididymal AT induction and infiltration of activated T cells, an accumulation and polarization of macrophages, and an increase in populations of activated CD4⁺ T cells and CD8⁺ T cells that express CXCR3 or killer cell lectin-like receptor subfamily G member 1 (KLRG1). Levels of inflammatory cytokines and leptin and the results of in vitro co-culture experiments revealed interactions among HFD- and ND-induced CD8⁺ T cells, macrophages, and adipocytes. Our findings suggest that obese tissues activate and induce both CD4⁺ and CD8⁺ CD69⁺ T cells and augment the expression of CXCR3 receptors, which promotes the recruitment and numbers of pro-inflammatory M1 macrophages to maintain low-grade chronic inflammation. The results support the hypothesis that CXCR3-expressing CD8⁺T cells play an essential role in the initiation and maintenance of adipose tissue inflammation.

CXCR3 Ligands in Cancer and Autoimmunity, Chemoattraction of Effector T Cells, and Beyond

CXCR3 is a chemokine receptor with three ligands; CXCL9, CXCL10, and CXCL11. CXCL11 binds CXCR3 with a higher affinity than the other ligands leading to receptor internalization. Long ago we reported that one of these chemokines, CXCL10, not only attracts CXCR3+ CD4+ and CD8+ effector T cells to sites of inflammation, but also direct their polarization into highly potent effector T cells. Later we showed that CXCL11 directs the linage development of T-regulatory-1 cells (Tr1). We also observed that CXCL11 and CXCL10 induce different signaling cascades via CXCR3. Collectively this suggests that CXCR3 ligands differentially regulate the biological function of T cells via biased signaling. It is generally accepted that tumor cells evolved to express several chemokine receptors and secrete their ligands. Vast majority of these chemokines support tumor growth by different mechanisms that are discussed. We suggest that CXCL10 and possibly CXCL9 differ from other chemokines by their ability to restrain tumor growth and enhance anti-tumor immunity. Along with this an accumulating number of studies showed in various human cancers a clear association between poor prognosis and low expression of CXCL10 at tumor sites, and vice versa. Finally, we discuss the possibility that CXCL9 and CXCL10 may differ in their biological function via biased signaling and its possible relevance to cancer immunotherapy. The current mini review focuses on exploring the role of CXCR3 ligands in directing the biological properties of CD4+ and CD8+ T cells in the context of cancer and autoimmunity. We believe that the combined role of these chemokines in attracting T cells and also directing their biological properties makes them key drivers of immune function.

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.

Mesenchymal Stem Cells Decrease Oxidative Stress in the Bowels of Interleukin-10 Knockout Mice

Background/Aims: Inflammatory bowel disease (IBD) is an autoimmune disease characterized by chronic inflammation mainly in the large intestine. The interleukin-10 knockout (IL-10 KO) mouse is a well-known animal model of IBD that develops spontaneous intestinal inflammation resembling Crohn's disease. Oxidative stress is considered to be the leading cause of cell and tissue damage. Reactive oxygen species (ROS) can cause direct cell injury and/or indirect cell injury by inducing the secretion of cytokines from damaged cells. This study evaluated the effects of mesenchymal stem cell (MSC) on the progression of IBD. Methods: In this study, human bone marrow-derived MSCs were injected into IL-10 KO mice (MSC). Oxidative stress and inflammation levels were evaluated in the large intestine and compared with those in control IL-10 KO mice (CON) and normal wild-type control mice (Wild). Results: The levels of ROS (superoxide and hydrogen peroxidase) and a secondary end-product of lipid peroxidation (malondialdehyde) were considerably higher in the CON, while superoxide dismutase and catalase levels were lower in the MSC. Inflammation-related marker (interferon-γ, tumor necrosis factor-α, IL-4, and CD8) expression and inflammatory histological changes were much less pronounced in MSC than in CON. Conclusions: MSCs affect the redox balance, leading to the suppression of IBD.

Sex-related Alterations of Gut Microbiota in the C57BL/6 Mouse Model of Inflammatory Bowel Disease

Background

Gut microbiota is closely associated with development and exacerbation of inflammatory bowel diseases (IBD). The aim of this study was to investigate differences in gut microbiota depending on sex and changes of gut microbiota during IBD developments.

Methods

16s rRNA metagenomic sequencing was performed for fecal materials from 8-week-old wild type (WT) and interleukin 10 (IL-10) knockout (KO) C57BL/6 mice of both sexes. Diversity indices, relative abundance of microbiota, and linear discriminant analysis effect size were examined to compare microbial communities between groups. Clustering of groups was performed by principal coordinates analysis (PCoA) and unweighted pair group method with arithmetic mean (UPGMA). Functional capabilities of microbiota were estimated using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) based on Kyoto Encyclopedia of Genes and Genomes database.

Results

PCoA and UPGMA tree analysis of beta-diversity demonstrated significant differences in gut microbiota between male and female groups of WT mice, but not of IL-10 KO mice. Firmicutes to Bacteroides ratio was higher in male group than that in female group in both WT mice and IL-10 KO mice. Phylum Proteobacteria significantly increased in female IL-10 KO mice than that in female WT mice. At species level, Lactobacillus murinus, Bacteroides acidifaciens, and Helicobacter hepaticus significantly increased in IL-10 KO mice than in WT mice. The relative abundance of beta-glucuronidase (K01195) was higher in female IL-10 KO mice than that in female WT mice by PICRUSt.

Conclusions

Our results suggest that microbiota-host interactions might differ between sexes during development of IBD.

An endogenous aryl hydrocarbon receptor ligand, ITE, induces regulatory T cells and ameliorates experimental colitis

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that affects millions of people with high morbidity and health care costs. The precise etiology of IBD is unknown, but clear evidence suggests that intestinal inflammation is caused by an excessive immune response to mucosal antigens. Recent studies have shown that activation of the aryl hydrocarbon receptor (AhR) induces regulatory T cells (Tregs) and suppresses autoimmune diseases. In the current study, we investigated if a nontoxic ligand of AhR, 2-(1' H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), can attenuate dextran sodium sulfate-induced colitis. Our studies demonstrated that in mice that received ITE treatment in vivo, colitis pathogenesis, including a decrease in body weight, was significantly reversed along with the systemic and intestinal inflammatory cytokines. ITE increased the expression of Tregs in spleen, mesenteric lymph nodes (MLNs), and colon lamina propria lymphocytes (cLPL) of mice with colitis when compared with controls. This induction of Tregs was reversed by AhR antagonist treatment in vitro. ITE treatment also increased dendritic cells (CD11c⁺) and decreased macrophages (F4/80⁺) from the spleen, MLNs, and cLPL in mice with colitis. ITE also reversed the systemic and intestinal frequency of CD4⁺ T cells during colitis and suppressed inflammatory cytokines including IFN-γ, TNF-α, IL-17, IL-6, and IL-1 as well as induced IL-10 levels. These findings suggest that ITE attenuates colitis through induction of Tregs and reduction in inflammatory CD4⁺ T cells and cytokines. Therefore, our work demonstrates that the nontoxic endogenous AhR ligand ITE may serve as a therapeutic modality to treat IBD. NEW & NOTEWORTHY We report the novel finding that activation of the aryl hydrocarbon receptor with the nontoxic ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) induces regulatory T cells (Tregs) and suppresses inflammatory bowel disease (IBD). Our data suggest that ITE diminishes colitis pathology through induction of Tregs; reduces inflammatory cytokines, inflammation score, and macrophage frequency; and induces DCs resulting in amelioration of colitis. Therefore, nontoxic endogenous ITE promotes the induction of Tregs and may be useful for the treatment of IBD.

Fatty acid amide hydrolase (FAAH) blockade ameliorates experimental colitis by altering microRNA expression and suppressing inflammation

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), which is thought to result from immune-mediated inflammatory disorders, leads to high morbidity and health care cost. Fatty acid amide hydrolase (FAAH) is an enzyme crucially involved in the modulation of intestinal physiology through anandamide (AEA) and other endocannabinoids. Here we examined the effects of an FAAH inhibitor (FAAH-II), on dextran sodium sulphate (DSS)-induced experimental colitis in mice. Treatments with FAAH-II improved overall clinical scores by reversing weight loss and colitis-associated pathogenesis. The frequencies of activated CD4⁺ T cells in spleens, mesenteric lymph nodes (MLNs), Peyer's patches (PPs), and colon lamina propiria (LP) were reduced by FAAH inhibition. Similarly, the frequencies of macrophages, neutrophils, natural killer (NK), and NKT cells in the PPs and LP of mice with colitis declined after FAAH blockade, as did concentrations of systemic and colon inflammatory cytokines. Microarray analysis showed that 26 miRNAs from MLNs and 217 from PPs had a 1.5-fold greater difference in expression after FAAH inhibition. Among them, 8 miRNAs were determined by reverse-transcription polymerase chain reaction (RT-PCR) analysis to have anti-inflammatory properties. Pathway analysis demonstrated that differentially regulated miRNAs target mRNA associated with inflammation. Thus, FAAH-II ameliorates experimental colitis by reducing not only the number of activated T cells but also the frequency of macrophages, neutrophils, and NK/NKT cell, as well as inflammatory miRNAs and cytokine at effector sites in the colon. These studies demonstrate for the first time that FAAH-II inhibitor may suppress colitis through regulation of pro-inflammatory miRNAs expression.

Inflammatory bowel disease: exploring gut pathophysiology for novel therapeutic targets

Ulcerative colitis and Crohn's disease are the 2 major phenotypes of inflammatory bowel disease (IBD), which are influenced by a complex interplay of immunological and genetic elements, though the precise etiology still remains unknown. With IBD developing into a globally prevailing disease, there is a need to explore new targets and a thorough understanding of the pathophysiological differences between the healthy and diseased gut could unearth new therapeutic opportunities. In this review, we provide an overview of the major aspects of IBD pathogenesis and thereafter present a comprehensive analysis of the gut pathophysiology leading to a discussion on some of the most promising targets and biologic therapies currently being explored. These include various gut proteins (CXCL-10, GATA-3, NKG2D, CD98, microRNAs), immune cells recruited to the gut (mast cells, eosinophils, toll-like receptors 2, 4), dysregulated proinflammatory cytokines (interleukin-6, -13, -18, -21), and commensal microbiota (probiotics and fecal microbiota transplantation). We also evaluate some of the emerging nonconventional therapies being explored in IBD treatment focusing on the latest developments in stem cell research, oral targeting of the gut-associated lymphoid tissue, novel anti-inflammatory signaling pathway targeting, adenosine deaminase inhibition, and the beneficial effects of antioxidant and nutraceutical therapies. In addition, we highlight the growth of biologics and their targets in IBD by providing information on the preclinical and clinical development of over 60 biopharmaceuticals representing the state of the art in ulcerative colitis and Crohn's disease drug development.

Qingchang Wenzhong Decoction Ameliorates Dextran Sulphate Sodium-Induced Ulcerative Colitis in Rats by Downregulating the IP10/CXCR3 Axis-Mediated Inflammatory Response

Qingchang Wenzhong Decoction (QCWZD) is an effective traditional Chinese medicine prescription. Our previous studies have shown that QCWZD has significant efficacy in patients with mild-to-moderate ulcerative colitis (UC) and in colonic mucosa repair in UC rat models. However, the exact underlying mechanism remains unknown. Thus, this study was conducted to determine QCWZD's efficacy and mechanism in dextran sulphate sodium- (DSS-) induced UC rat models, which were established by 7-day administration of 4.5% DSS solution. QCWZD was administered daily for 7 days, after which the rats were euthanized. Disease activity index (DAI), histological score (HS), and myeloperoxidase (MPO) level were determined to evaluate UC severity. Serum interferon gamma-induced protein 10 (IP10) levels were determined using ELISA kits. Western blotting and real-time polymerase chain reaction were, respectively, used to determine colonic protein and gene expression of IP10, chemokine (cys-x-cys motif) receptor (CXCR)3, and nuclear factor- (NF-) κB p65. Intragastric QCWZD administration ameliorated DSS-induced UC, as evidenced by decreased DAI, HS, and MPO levels. Furthermore, QCWZD decreased the protein and gene expression of IP10, CXCR3, and NF-κB p65. Overall, these results suggest that QCWZD ameliorates DSS-induced UC in rats by downregulating the IP10/CXCR3 axis-mediated inflammatory response and may be a novel UC therapy.

Oral mixture of autologous colon-extracted proteins for the Crohn’s disease: A double-blind trial

AIM: To evaluate the safety and efficacy of oral administration of Alequel™, an autologous protein-containing colon extract.

METHODS: A total of 43 patients were enrolled in a randomized, placebo-controlled, double-blind trial. Patients were orally administered with autologous protein-containing colon extract three doses of autologous study drug per week for 15 wk, for a total of 45 doses. Patients were followed for safety parameters. Remission was defined as a Crohn’s disease activity index (CDAI) score of less than or equal to 150. All patients were followed for changes in subsets of T cells by fluorescence-activated cell sorting analysis.

RESULTS: Analysis was performed on a total number of evaluable patients of 14 in the study drug group and 15 in the placebo group. Treatment was well tolerated by all patients. No major treatment-related adverse events were reported or observed in any of the treated patients during the feeding or follow-up periods. Between weeks 6 and 9 of the study, six of the 14 (43%) evaluable subjects who received the study drug achieved a CDAI of 150 or lower. In contrast, five of the 15 (33%) evaluable subjects in the placebo group achieved remission. Between weeks 9 and 12, the remission rates were 50% and 33% for the drug group and placebo group, respectively. Among the drug-treated subjects who achieved remission, the effect of the drug was judged as stable in eight of the 14 subjects as measured by at least two CDAI scores indicating remission in the 15-wk treatment period. A decreased percentage of peripheral natural killer T regulatory cells (a decrease of 28% vs an increase of 16%) and an increased ratio of CD4⁺/CD8⁺ T lymphocytes (an increase of 11% vs a decrease of 9%) were noted in subjects with a significant clinical response.

CONCLUSION: Oral administration of the autologous colonic extract could be a safe and effective for the treatment of patients with moderate to severe Crohn’s disease.

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.

Generation of primary human intestinal T cell transcriptomes reveals differential expression at genetic risk loci for immune-mediated disease

OBJECTIVE

Genome-wide association studies (GWAS) have identified genetic variants within multiple risk loci as predisposing to intestinal inflammatory diseases, including Crohn's disease, ulcerative colitis and coeliac disease. Most risk variants affect regulation of transcription, but a critical challenge is to identify which genes and which cell types these variants affect. We aimed to characterise whole transcriptomes for each common T lymphocyte subset resident within the gut mucosa, and use these to infer biological insights and highlight candidate genes of interest within GWAS risk loci.

DESIGN

We isolated the four major intestinal T cell populations from pinch biopsies from healthy subjects and generated transcriptomes for each. We computationally integrated these transcriptomes with GWAS data from immune-related diseases.

RESULTS

Robust, high quality transcriptomic data were generated from 1 ng of RNA from precisely sorted cell subsets. Gene expression patterns clearly differentiated intestinal T cells from counterparts in peripheral blood and revealed distinct signalling pathways for each intestinal T cell subset. Intestinal-specific T cell transcripts were enriched in GWAS risk loci for Crohn's disease, ulcerative colitis and coeliac disease, but also specific extraintestinal immune-mediated diseases, allowing prediction of novel candidate genes.

CONCLUSIONS

This is the first report of transcriptomes for minimally manipulated intestinal T lymphocyte subsets in humans. We have demonstrated that careful processing of mucosal biopsies allows the generation of transcriptomes from as few as 1000 highly purified cells with minimal interindividual variation. Bioinformatic integration of transcriptomic data with recent GWAS data identified specific candidate genes and cell types for inflammatory pathologies.

Expression of neuronal CXCL10 induced by rabies virus infection initiates infiltration of inflammatory cells, production of chemokines and cytokines, and enhancement of blood-brain barrier permeability

It has been shown that enhancement of blood-brain barrier (BBB) permeability is modulated by the expression of chemokines/cytokines and reduction of tight junction (TJ) proteins in the brains of mice infected with rabies virus (RABV). Since CXCL10 was found to be the most highly expressed chemokine, its temporal and spatial expression were determined in the present study. The expression of the chemokine CXCL10 was initially detected in neurons as early as 3 days postinfection (p.i.) in the brains of RABV-infected mice, after which it was detected in microglia (6 days p.i.) and astrocytes (9 days p.i.). Neutralization of CXCL10 by treatment with anti-CXCL10 antibodies reduced gamma interferon (IFN-γ) production and Th17 cell infiltration, as well as restoring TJ protein expression and BBB integrity. Together, these data suggest that it is the neuronal CXCL10 that initiates the cascade that leads to the activation of microglia/astrocytes, infiltration of inflammatory cells, expression of chemokines/cytokines, reduction of TJ protein expression, and enhancement of the BBB permeability.

Human adipose-derived stem cells attenuate inflammatory bowel disease in IL-10 knockout mice

Inflammatory bowel disease (IBD) is a complex immunological disorder characterized by chronic inflammation caused mainly by unknown factors. The interleukin-10 knockout (IL-10 KO) mouse is a well-established murine model of IBD which develops spontaneous intestinal inflammation that resembles Crohn's disease. In the present study, human adipose-derived mesenchymal stem cells (hAMSCs) were administrated to IL-10 KO mice to evaluate the anti-inflammatory effects of hAMSCs that may attenuate the progress of or treat IBD. After IBD was induced by feeding the IL-10 KO mouse a 125-250 ppm piroxicam mixed diet for 1 week, 2×10(6) hAMSCs were injected into the peritoneum and the mice were switched to a normal diet. After 1 week, the mice were sacrificed and tissue samples were harvested. Tissue scores for inflammation and inflammation-related genes expression were determined. The hAMSC-treated group showed significantly reduced inflammatory changes in histological analysis. Reverse transcription-PCR analysis showed that RANTES, Toll-like receptor 9, and IL-4 expression levels were not significantly different between the groups while IL-12, INF-γ, and TNF-α levels were significantly decreased in the hAMSC treated group. hAMSC attenuated IBD in the IL-10 KO mice by suppressing inflammatory cytokine expression, was mediated by the type 1 helper T cell pathway. Even though only a single injection of hAMSCs was delivered, the effect influenced chronic events associated with inflammatory changes and demonstrated that hAMSCs are a powerful candidate for IBD therapy.

Transcriptome profiling of CTLs regulated by rapamycin using RNA-Seq

Memory programming of cytotoxic T cells (CTLs) by inflammatory cytokines can be regulated by mammalian target of rapamycin (mTOR). We have shown that inhibition of mTOR during CTL activation leads to the enhancement of memory, but the molecular mechanisms remain largely unknown. Using high-throughput RNA-Seq, we identified genes and functions in mouse CTLs affected by mTOR inhibition through rapamycin. Of the 43,221 identified transcripts, 184 transcripts were differentially expressed after rapamycin treatment, corresponding to 128 annotated genes. Of these genes, 114 were downregulated and only 14 were upregulated. Most importantly, 50 of them are directly related to cell death and survival. In addition, several genes such as CD62L are related to migration. Furthermore, we predicted downregulation of transcriptional regulators based on the total differentially expressed genes, as well as the subset of apoptosis-related genes. Quantitative PCR confirmed the differential expressions detected in RNA-Seq. We conclude that the regulatory function of rapamycin may work through inhibition of multiple genes related to apoptosis and migration, which enhance CTL survival into memory.

The severity of experimental autoimmune cystitis can be ameliorated by anti-CXCL10 Ab treatment

Background

Interstitial cystitis (IC), more recently called painful bladder syndrome (PBS) is a complex disease associated with chronic bladder inflammation that primarily affects women. Its symptoms include frequent urinary urgency accompanied by discomfort or pain in the bladder and lower abdomen. In the United States, eight million people, mostly women, have IC/PBS. New evidence that autoimmune mechanisms are important in the pathogenesis of IC/PBS triggered interest.

Methodology/Principal Findings

SWXJ mice immunized with a homogenate of similar mice’s urinary bladders develop an autoimmune phenotype comparable to clinical IC with functional and histological alterations confined to the urinary bladder. Using the murine model of experimental autoimmune cystitis (EAC), we found that serum levels of CXCR3 ligand and local T helper type 1 (Th1) cytokine are elevated. Also, IFN-γ-inducible protein10 (CXCL10) blockade attenuated overall cystitis severity scores; reversed the development of IC; decreased local production of CXCR3 and its ligands, IFN-γ, and tumor necrosis factor-α (TNF-α); and lowered systemic levels of CXCR3 ligands. Urinary bladder CD4⁺ T cells, mast cells, and neutrophils infiltrates were reduced following anti-CXCL10 antibody (Ab) treatment of mice. Anti-CXCL10 Ab treatment also reversed the upregulated level of CXCR3 ligand mRNA at urinary bladder sites. The decreased number and percentage of systemic CD4⁺ T cells in EAC mice returned to normal after anti-CXCL10 Ab treatment.

Conclusion/Significance

Taken together, our findings provide important new information about the mechanisms underlying EAC pathogenesis, which has symptoms similar to those of IC/PBS. CXCL10 has the potential for use in developing new therapy for IC/PBS.

International Union of Basic and Clinical Pharmacology. [corrected]. LXXXIX. Update on the extended family of chemokine receptors and introducing a new nomenclature for atypical chemokine receptors

Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145-176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human Genome Nomenclature Committee.

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.

The role of interferon-γ inducible protein-10 in a mouse model of acute liver injury post induced pluripotent stem cells transplantation

Background

Liver injuries are important medical problems that require effective therapy. Stem cell or hepatocyte transplantation has the potential to restore function of the damaged liver and ameliorate injury. However, the regulatory factors crucial for the repair and regeneration after cell transplantation have not been fully characterized. Our study investigated the effects and the expression of the regulatory factors in mouse models of acute liver injury either transplanted with the induced pluripotent stem cells (iPS) or the hepatocytes that differentiated from iPS cells (iHL).

Methods/Principal Findings

Mice received CCl₄ injection and were randomized to receive vehicle, iPS, or iHL transfusions vial tail veins and were observed for 24, 48 or 72 hours. The group of mice with iPS transplantation performed better than the group of mice receiving iHL in reducing the serum alanine aminotransferase, aspartate aminotransferase, and liver necrosis areas at 24 hours after CCl₄ injury. Moreover, iPS significantly increased the numbers of proliferating hepatocytes at 48 hours. Cytokine array identified that chemokine IP-10 could be the potential regulatory factor that ameliorates liver injury. Further studies revealed that iPS secreted IP-10 in vitro and transfusion of iPS increased IP-10 protein and mRNA expressions in the injured livers in vivo. The primary hepatocytes and non-parenchyma cells were isolated from normal and injured livers. Hepatocytes from injured livers that received iPS treatment expressed more IP-10 mRNA than their non-hepatocyte counter-parts. In addition, animal studies revealed that administration of recombinant IP-10 (rIP-10) effectively reduced liver injuries while IP-10-neutralizing antibody attenuated the protective effects of iPS and decreased hepatocyte proliferation. Both iPS and rIP-10 significantly reduced the 72-hour mortality rate in mice that received multiple CCl₄-injuries.

Conclusions/Significance

These findings suggested that IP-10 may have an important regulatory role in facilitating the repair and regeneration of injured liver after iPS transplantation.

Natural killer T cells suppress zymosan A-mediated granuloma formation in the liver by modulating interferon-γ and interleukin-10

Wild-type (WT) and CD1d(-/-) [without natural killer (NK) T cells] mice were treated with zymosan A to induce granuloma formation in the liver. Increased granuloma formation was seen in NKT-less mice on days 7 and 14 after administration. WT mice showed limited granuloma formation, and zymosan A eventually induced NKT cell accumulation as identified by their surface marker (e.g. CD1d-tetramer). Zymosan A augmented the expression of Toll-like receptor 2 on the cell surface of both macrophages and NKT cells. One possible reason for accelerated granuloma formation in NKT-less mice was increased production of interferon- γ (IFN-γ); a theory that was confirmed using IFN-γ(-/-) mice. Also, zymosan A increased interleukin-10 production in WT mice, which suppresses IFN-γ production. Taken together, these results suggest that NKT cells in the liver have the potential to suppress zymosan A-mediated granuloma formation.

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.

A phase II, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of MDX-1100, a fully human anti-CXCL10 monoclonal antibody, in combination with methotrexate in patients with rheumatoid arthritis

OBJECTIVE

CXCL10 (also known as interferon-γ-inducible 10-kd protein [IP-10]) is a chemokine that potentially plays a role in the immunopathogenesis of rheumatoid arthritis (RA). We undertook this phase II study to evaluate the efficacy and safety of MDX-1100, a fully human, anti-CXCL10 (anti-IP-10) monoclonal antibody, in RA patients whose disease responded inadequately to methotrexate (MTX).

METHODS

Patients with active RA receiving stable doses of MTX (10-25 mg weekly) were randomized to receive intravenous doses of 10 mg/kg MDX-1100 (n = 35) or placebo (n = 35) every other week. The primary end point was the proportion of patients meeting the American College of Rheumatology 20% improvement criteria (achieving an ACR20 response) on day 85, and patients were followed up for safety to day 141.

RESULTS

The ACR20 response rate was significantly higher among MDX-1100-treated patients than among placebo-treated patients (54% versus 17%; P = 0.0024). Statistically significant differences in the ACR20 response rate between treatments were observed starting on day 43 (P < 0.05). The ACR50 and ACR70 response rates on day 85 did not differ between the groups. Overall, 51.4% of MDX-1100-treated patients and 30.3% of placebo-treated patients experienced at least 1 adverse event (AE). No study drug-related serious AEs were reported.

CONCLUSION

MDX-1100 was well tolerated and demonstrated clinical efficacy in RA patients whose disease responded inadequately to MTX. This is the first study to demonstrate clinical efficacy of a chemokine inhibitor in RA and supports the notion of a potential role of IP-10 in the immunopathogenesis of RA.

Cannabinoid receptor-2 (CB2) agonist ameliorates colitis in IL-10(-/-) mice by attenuating the activation of T cells and promoting their apoptosis

Inflammatory bowel disease (IBD) is a chronic intestinal inflammation caused by hyperactivated effector immune cells that produce pro-inflammatory cytokines. Recent studies have shown that the cannabinoid system may play a critical role in mediating protection against intestinal inflammation. However, the effect of cannabinoid receptor induction after chronic colitis progression has not been investigated. Here, we investigate the effect of cannabinoid receptor-2 (CB2) agonist, JWH-133, after chronic colitis in IL-10(-/-) mice. JWH-133 effectively attenuated the overall clinical score, and reversed colitis-associated pathogenesis and decrease in body weight in IL-10(-/-) mice. After JWH-133 treatment, the percentage of CD4(+) T cells, neutrophils, mast cells, natural killer (NK1.1) cells, and activated T cells declined in the intestinal lamina propria (LP) and mesenteric lymph nodes (MLN) of mice with chronic colitis. JWH-133 was also effective in ameliorating dextran sodium sulfate (DSS)-induced colitis. In this model, JWH-133 reduced the number and percentage of macrophages and IFN-γ expressing cells that were induced during colitis progression. Treatment with aminoalkylindole 6-iodo-pravadoline (AM630), a CB2 receptor antagonist, reversed the colitis protection provided by JWH-133 treatment. Also, activated T cells were found to undergo apoptosis following JWH-133 treatment both in-vivo and in-vitro. These findings suggest that JWH-133 mediates its effect through CB2 receptors, and ameliorates chronic colitis by inducing apoptosis in activated T cells, reducing the numbers of activated T cells, and suppressing induction of mast cells, NK cells, and neutrophils at sites of inflammation in the LP. These results support the idea that the CB2 receptor agonists may serve as a therapeutic modality against IBD.

Apple polyphenols require T cells to ameliorate dextran sulfate sodium-induced colitis and dampen proinflammatory cytokine expression

Human IBD, including UC and Crohn's disease, is characterized by a chronic, relapsing, and remitting condition that exhibits various features of immunological inflammation and affects at least one/1000 people in Western countries. Polyphenol extracts from a variety of plants have been shown to have immunomodulatory and anti-inflammatory effects. In this study, treatment with APP was investigated to ameliorate chemically induced colitis. Oral but not peritoneal administration of APP during colitis induction significantly protected C57BL/6 mice against disease, as evidenced by the lack of weight loss, colonic inflammation, and shortening of the colon. APP administration dampened the mRNA expression of IL-1β, TNF-α, IL-6, IL-17, IL-22, CXCL9, CXCL10, CXCL11, and IFN-γ in the colons of mice with colitis. APP-mediated protection requires T cells, as protection was abated in Rag-1(-/-) or TCRα(-/-) mice but not in IL-10(-/-), IRF-1(-/-), μMT, or TCRδ(-/-) mice. Administration of APP during colitis to TCRα(-/-) mice actually enhanced proinflammatory cytokine expression, further demonstrating a requirement for TCRαβ cells in APP-mediated protection. APP treatment also inhibited CXCR3 expression by TCRαβ cells, but not B or NK cells, in the colons of mice with colitis; however, depletion of CD4(+) or CD8(+) T cells alone did not abolish APP-mediated protection. Collectively, these results show that oral administration of APP protects against experimental colitis and diminishes proinflammatory cytokine expression via T cells.

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 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.

CD8+CD122+ regulatory T cells (Tregs) and CD4+ Tregs cooperatively prevent and cure CD4+ cell-induced colitis

We identified CD8(+)CD122(+) regulatory T cells (Tregs) and demonstrated their importance in the maintenance of immune homeostasis and in the recovery from experimental autoimmune encephalomyelitis. In this paper, we show that CD8(+)CD122(+) Tregs effectively prevent and cure colitis in a mouse model. In our experiments, colitis was induced in lymphocyte-deficient RAG-2(-/-) mice by transferring CD4(+)CD45RB(high) cells that were excluded with CD4(+) Tregs. Cotransfer of CD8(+)CD122(+) cells clearly suppressed the development of colitis, and this suppressive effect was similar to that of CD4(+)CD45RB(low) cells that were mostly CD4(+) Tregs. CD8(+)CD122(+) cells obtained from IL-10(-/-) mice were unable to suppress colitis, indicating that IL-10 is an important effect-transmitting factor in the suppression of colitis. CD8(+)CD122(+) cells showed a suppressive effect when they were transferred 4 wk after CD4(+)CD45RB(high) cells, indicating the therapeutic potential of CD8(+)CD122(+) cells. A mixture of CD8(+)CD122(+) cells and CD4(+)CD45RB(low) cells was far more effective than single Tregs, indicating the synergistic effect of these Tregs. These overall findings demonstrate the potential role of CD8(+) Tregs, and possibly together with CD4(+) Tregs, in the medical care of inflammatory bowel disease patients.

Stem cells as potential therapeutic targets for inflammatory bowel disease

The incidence and prevalence of Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), are rising. According to some estimates >1 million new cases of IBD arise in the United States annually. The conventional therapies available for IBD range from anti-inflammatory drugs to immunosuppressive agents, but these therapies generally fail to achieve satisfactory results due to their side effects. Interest in a new therapeutic option, that is, biological therapy, has gained much momentum recently due to its focus on different stages of the inflammatory process. Stem cell (SC) research has become a new direction for IBD therapy due to our recent understanding of cell populations involved in the pathogenic process. To this end, hematopoietic and mesenchymal stem cells are receiving more attention from IBD investigators. The intestinal environment, with its crypts and niches, supports incoming embryonic and hematopoietic stem cells and allows them to engraft and differentiate. The above findings suggest that, in the future, SC-based therapy will be a promising alternative to conventional therapy for IBD. In this review, we discuss SCs as potential therapeutic targets for future treatment of IBD.

Delayed resolution of acute inflammation in ulcerative colitis is associated with elevated cytokine release downstream of TLR4

Background

Ulcerative colitis (UC) is widely viewed as a leukocyte-mediated disorder. Although strong evidence implicates an exuberant response to microbial components in its pathogenesis, no intrinsic immune defect has been identified and the underlying pathogenic mechanisms remain obscure.

Methodology/Principal Findings

The acute immune response to bacterial injection was determined in UC patients with quiescent disease and directly compared to healthy control subjects. Monocyte-derived macrophages were used to investigate bacterial recognition mechanisms in vitro. An exuberant and protracted acute inflammatory response to bacteria was evident in patients with UC, which coincides with increased systemic levels of CXCL10. Macrophages stimulated with bacteria and Toll-like receptor (TLR) ligands revealed a specific defect in the TLR4 response in UC. The defect resulted in the over-expression of a number of pro-inflammatory molecules under transcriptional control of the adaptor TIR-domain containing adaptor inducing interferon-β (TRIF).

Conclusion

These findings highlight a dysregulated innate immune response with over-expression of molecules associated with leukocyte recruitment and activation that may eventuate in the hallmark chronic immune-mediated inflammation of UC.

A new model of chronic hapten-induced colitis in young rats

AIM AND OBJECTIVE

: Chronic models of inflammatory bowel disease are lacking in preadult rodents. The primary goal of our study was to develop a chronic model of hapten-induced intestinal inflammation and fibrosis in young rats. Second, we aimed to determine the profiles of key Th-1, Th-2, and Th-17 proinflammatory and profibrotic cytokines, during the progression of colitis in young rats.

MATERIALS AND METHODS

Chronic hapten-induced colitis was induced by the administration of intracolonic 2,4,6-trinitrobenzene sulfonic acid (TNBS) in young Wistar rats (postnatal days 23, 35, 48, and 59). After 1, 3, or 4 cycles of TNBS, rats were euthanized and the colons were removed for the measurement of macroscopic, histologic, and biochemical parameters of colitis.

RESULTS

Young rats developed moderate to severe colitis in the distal colon, without significant morbidity or mortality. Macroscopic severity, histologic pathology, and colonic weights increased progressively with repeated TNBS administration. Cobblestone-like ulceration and fibrosis was evident in the colon, particularly after 4 cycles of TNBS. There was a unique cytokine pattern associated with colitis in young rats. Interleukin (IL)-12 and tumor necrosis factor (TNF)-alpha peaked during the earlier postnatal time points (days 28 and 54) and then declined after repetitive administration of the hapten (day 67). In contrast, IL-13 and IL-17 were consistently elevated after administration of TNBS to the colon of young rats.

CONCLUSIONS

A new model of colitis was established in young rats, which has a unique pattern of Th-1, Th-2, and Th-17 cytokine induction. This chronic TNBS model may be useful for studying the development of inflammation and fibrosis in preadult animals.

Oral administration of Alequel, a mixture of autologous colon-extracted proteins for the treatment of Crohn's disease

The pathogenesis of Crohn's disease involves an immune-mediated damage to the gut mucosa. Current developed therapies are based on the use of immunosuppressive drugs that can lead to significant drug-related adverse responses. There is a need for a therapeutic strategy that is more specific and less global in its effect on the immune system. Oral tolerance is an active process wherein oral administration of antigens is associated with the induction of regulatory cells and the suppression of effector cells directed toward specific and nonspecific antigens. Studies in animal models of experimental colitis suggest that oral administration of proteins extracted from the gut can induce tolerance and alleviate the disease symptoms. Recent clinical trials showed that oral administration of Alequel, an autologous protein-containing colon extract, to patients with Crohn's disease is safe and may be effective as a therapeutic modality for treating the disease. This treatment was associated with disease-associated antigen alterations of the immune response in the patients. Oral administration of Alequel could provide a patient-tailored approach that is side-effect-free for the treatment of patients with Crohn's disease.

The localization and migration of natural killer cells in health and disease

Natural killer (NK) cells comprise a finite lymphocyte lineage with distinctive gene expression patterns. Natural killer (NK) cells develop in the bone marrow (BM) and are not static but populate secondary and primary lymphoid organs. A unique feature of NK cells is their expression of activating and inhibitory receptors, which allow them to respond either when ligands for activating receptors are upregulated or when ligands for inhibitory receptors are downregulated. The unique transcriptome of NK cells renders them capable of protecting the host from a vast array of disease states. Their undisputed importance in host protection is conferred by their ability to eliminate unhealthy cells. However, in order for NK cells to exert their effects, they need to be strategically located at the right places. This chapter provides an overview of the current understanding of the localization of NK cell populations and their ability to migrate in response to homeostatic and pathological conditions. NK cells develop in the BM, which they exit using specific molecular interactions. Exit from the BM is followed by localization to a number of tissues, including secondary lymphoid organs. Within each tissue, NK cells often acquire unique function and phenotype that is regulated by the local microenvironment. Their localization is primarily directed by the action of chemokines and therefore is in tight association with the activation status of the organism. Changes in chemokine expression during disease results in further NK cell mobilization and allows them to protect the host from infection and malignancy. Thus, from their time of production until their end, NK cells travel exhaustively over long distances and visit places that influence their already dynamic life.

Resveratrol (trans-3,5,4'-trihydroxystilbene) induces silent mating type information regulation-1 and down-regulates nuclear transcription factor-kappaB activation to abrogate dextran sulfate sodium-induced colitis

Inflammatory bowel disease is a chronic, relapsing, and tissue-destructive disease. Resveratrol (3,4,5-trihydroxy-trans-stilbene), a naturally occurring polyphenol that exhibits beneficial pleiotropic health effects, is recognized as one of the most promising natural molecules in the prevention and treatment of chronic inflammatory disease and autoimmune disorders. In the present study, we investigated the effect of resveratrol on dextran sodium sulfate (DSS)-induced colitis in mice and found that it effectively attenuated overall clinical scores as well as various pathological markers of colitis. Resveratrol reversed the colitis-associated decrease in body weight and increased levels of serum amyloid A, tumor necrosis factor-alpha, interleukin (IL-6), and IL-1beta. After resveratrol treatment, the percentage of CD4(+) T cells in mesenteric lymph nodes (MLN) of colitis mice was restored to normal levels, and there was a decrease in these cells in the colon lamina propria (LP). Likewise, the percentages of macrophages in MLN and the LP of mice with colitis were decreased after resveratrol treatment. Resveratrol also suppressed cyclooxygenase-2 (COX-2) expression induced in DSS-exposed mice. Colitis was associated with a decrease in silent mating type information regulation-1 (SIRT1) gene expression and an increase in p-inhibitory kappaB expression and nuclear transcription factor-kappaB (NF-kappaB) activation. Resveratrol treatment of mice with colitis significantly reversed these changes. This study demonstrates for the first time that SIRT1 is involved in colitis, functioning as an inverse regulator of NF-kappaB activation and inflammation. Furthermore, our results indicate that resveratrol may protect against colitis through up-regulation of SIRT1 in immune cells in the colon.

Metabolic assessment of gradual development of moderate experimental colitis in IL-10 deficient mice

Evidence has linked genetic predisposition and environmental exposures to the worldwide pandemic of inflammatory bowel diseases (IBD), but underlying biochemical events remain largely undefined. Here, we studied the gradual development of colitis in Interleukin 10 deficient mice using a combination of (i) histopathological analysis of intestinal sections, (ii) metabolic profiling of blood plasma, and (iii) measurement of plasma inflammatory biomarkers. Data integration using chemometric tools, including Independent Component Analysis, provided a new strategy for measuring and mapping the metabolic effects associated with the development of intestinal inflammation at the age of 1, 8, 16, and 24 weeks. Chronic inflammation appeared at 8 weeks and onward, and was associated with altered cecum and colon morphologies and increased inflammatory cell infiltration into the mucosa and the submucosa. Blood plasma profiles provided additional evidence of loss of energy homeostasis, impaired metabolism of lipoproteins and glycosylated proteins. In particular, IL-10-/-mice were characterized by decreased levels of VLDL and increased concentrations of LDL and polyunsaturated fatty acids, which are related to the etiology of IBD. Moreover, higher levels of lactate, pyruvate, citrate and lowered glucose suggested increased fatty acid oxidation and glycolysis, while higher levels of free amino acids reflected muscle atrophy, breakdown of proteins and interconversions of amino acids to produce energy. These integrated system investigations demonstrate the potential of metabonomics for investigating the mechanistic basis of IBD, and it will provide novel avenues for management of IBD.

The major outer membrane protein of a periodontopathogen induces IFN-beta and IFN-stimulated genes in monocytes via lipid raft and TANK-binding kinase 1/IFN regulatory factor-3

Surface molecules of pathogens play an important role in stimulating host immune responses. Elucidation of the signaling pathways activated by critical surface molecules in host cells provides insight into the molecular pathogenesis resulting from bacteria-host interactions. MspTL is the most abundant outer membrane protein of Treponema lecithinolyticum, which is associated with periodontitis, and induces expression of a variety of proinflammatory factors. Although bacteria and bacterial components like LPS and flagellin are known to induce IFN-beta, induction by bacterial surface proteins has not been reported. In the present study, we investigated MspTL-mediated activation of signaling pathways stimulating up-regulation of IFN-beta and IFN-stimulated genes in a human monocytic cell line, THP-1 cells, and primary cultured human gingival fibroblasts. MspTL treatment of the cells induced IFN-beta and the IFN-stimulated genes IFN-gamma-inducible protein-10 (IP-10) and RANTES. A neutralizing anti-IFN-beta Ab significantly reduced the expression of IP-10 and RANTES, as well as STAT-1 activation, which was also induced by MspTL. Experiments using specific small interfering RNA showed that MspTL activated TANK-binding kinase 1 (TBK1), but not inducible IkappaB kinase (IKKi). MspTL also induced dimerization of IFN regulatory factor-3 (IRF-3) and translocation into the nucleus. The lipid rapid-disrupting agents methyl-beta-cyclodextrin, nystatin, and filipin inhibited the MspTL internalization and cellular responses, demonstrating that lipid raft activation was a prerequisite for MspTL cellular signaling. Our results demonstrate that MspTL, the major outer protein of T. lecithinolyticum, induced IFN-beta expression and subsequent up-regulation of IP-10 and RANTES via TBK1/IRF-3/STAT-1 signaling secondary to lipid raft activation.

Specificity tuning of antibody fragments to neutralize two human chemokines with a single agent

Chemokines are important mediators of the immune response that are responsible for the trafficking of immune cells between lymphoid organs and migration towards sites of inflammation.Using phage display selection and a functional screening approach, we have isolated a panel of single-chain fragment variable (scFv) capable of neutralizing the activity of the human chemokine CXCL10 (hCXCL10). One of the isolated scFv was weakly cross-reactive against another human chemokine CXCL9,but was unable to block its biological activity. We diversified the complementarity determining region 3 (CDR3) of the light chain variable domain (VL) of this scFv and combined phage display with high throughput antibody array screening to identify variants capable of neutralizing both chemokines. Using this approach it is therefore possible to engineer pan-specific antibodies that could prove very useful to antagonize redundant signaling pathways such as the chemokine signaling network.

CXCL10 blockade protects mice from cyclophosphamide-induced cystitis

Background

Alterations in serum CXCR3 ligand levels were examined in interstitial cystitis (IC) patients; similar expression patterns in serum as well as CXCR3, CXCR3 ligands, and cytokines expressed by peripheral and local leukocyte subpopulations were characterized during cyclophosphamide (CYP)-induced acute cystitis in mice.

Results

Serum levels of monokine-induced by interferon-γ (IFN-γ) (MIG/CXCL9), IFN-γ-inducible protein-10 (IP-10/CXCL10), and IFN-γ-inducible T cell α chemoattractant (I-TAC/CXCL11) were elevated in patients with IC. These clinical features closely correlated with CYP-induced cystitis in mice. Serum levels of these CXCR3 ligands and local T helper type 1 (Th1) cytokines were also increased. We demonstrate that CXCR3 as well as CXCL9, CXCL10 and CXCL11 mRNA were significantly expressed by urinary bladder lymphocytes, while CXCR3 and CXCL9 transcripts were significantly expressed by iliac lymph node leukocytes following CYP treatment. We also show that the number of CD4⁺ T cells, mast cells, natural killer (NK) cells, and NKT cells were increased at systemic (spleen) and mucosal (urinary bladder and iliac lymph nodes) sites, following CYP-induced cystitis in mice. Importantly, CXCL10 blockade attenuated these increases caused by CYP.

Conclusion

Antibody (Ab)-mediated inhibition of the most abundant serum CXCR3 ligand, CXCL10, in mice decreased the local production of CXCR3 ligands as well as Th1 cytokines expressed by local leukocytes, and lowered corresponding serum levels to reduce the severity of CYP-induced cystitis. The present study is among the first to demonstrate some of the cellular and molecular mechanisms of chemokines in cystitis and may represent new drug target for this disease.

Role of natural killer cells in modulating dendritic cell responses to Leishmania amazonensis infection

The importance of the interaction between natural killer (NK) cells and dendritic cells (DCs) in the expansion of antiviral and antitumor immune responses is well-documented; however, limited information on DC-NK cell interaction during parasitic infections is available. Given that some Leishmania parasites are known to prevent or suppress DC activation, we developed a DC-NK cell coculture system to examine the role of NK cells in modulating the functions of Leishmania-infected DCs. We found that the addition of freshly isolated, resting NK cells significantly promoted the activation of DCs that were preinfected with Leishmania amazonensis promastigotes and that these activated DCs, in turn, stimulated NK cell activation mostly via cell contact-dependent mechanisms. Notably, L. amazonensis amastigote infection failed to activate DCs, and this lack of DC activation could be partially reversed by the addition of preactivated NK (ANK) cells but not resting NK cells. Moreover, the adoptive transfer of ANK cells into L. amazonensis-infected mice markedly increased DC and T-cell activation and reduced tissue parasite loads at 1 and 3 weeks postinfection. These results suggest differential roles of DC-NK cell cross talk at different stages of Leishmania infection and provide new insight into the interplay of components of the innate immune system during parasitic infection.

CXCL10+ T cells and NK cells assist in the recruitment and activation of CXCR3+ and CXCL11+ leukocytes during Mycobacteria-enhanced colitis

Background

The role of Mycobacteria in the etiology of Crohn's disease (CD) has been a contentious subject for many years. Recently, our laboratory showed that spontaneous colitis in IL-10^-/- mice is driven in part by antigens (Ags) conserved in Mycobacteria. The present study dissects some of the common cellular and molecular mechanism that drive Mycobacteria-mediated and spontaneous colitis in IL-10^-/- mice.

Results

We show that serum from inflammatory bowel disease (IBD) patients contain significantly higher levels of Mycobacterium avium paratuberculosis-specific IgG1 and IgG2 antibodies (Abs), serum amyloid A (SAA) as well as CXCR3 ligands than serum from healthy donors. To study the cellular mechanisms of Mycobacteria-associated colitis, pathogen-free IL-10^-/- mice were given heat-killed or live M. avium paratuberculosis. The numbers of mucosal T cells, neutrophils, NK/NKT cells that expressed TNFα, IFN-γ, and/or CXCL10 were significantly higher in mice that received live Mycobacteria than other groups. The numbers of mucosal CXCR3⁺, CXCL9⁺, CXCL11⁺ and/or IFN-γ⁺ dendritic cells (DCs) were also significantly higher in M. avium paratuberculosis-challenged mice, than compared to control mice.

Conclusion

The present study shows that CD and UC patients mount significant Mycobacteria-specific IgG1 > IgG2 and CXCR3 ligand responses. Several cellular mechanisms that drive spontaneous colitis also mediate Mycobacteria-enhanced colitis in IL-10^-/- mice. Similar to IL-10^-/- mice under conventional housing, we show that Mycobacteria-challenge IL-10^-/- mice housed under otherwise pathogen-free conditions develop colitis that is driven by CXCR3- and CXCR3 ligand-expressing leukocytes, which underscores another important hallmark and molecular mechanism of colitis. Together, the data show that Mycobacteria-dependent host responses, namely CXCL10⁺ T cells and NK cells, assist in the recruitment and activation of CXCR3⁺ and CXCL11⁺ leukocytes to enhance colitis of susceptible hosts.