Interleukin-22, a member of the IL-10 subfamily, induces inflammatory responses in colonic subepithelial myofibroblasts

Protective role of Th17 cells in pulmonary infection

Th17 cells are characterized as preferential producer of interleukins including IL-17A, IL-17F, IL-21 and IL-22. Corresponding receptors of these cytokines are expressed on number of cell types found in the mucosa, including epithelial cells and fibroblasts which constitute the prime targets of the Th17-associated cytokines. Binding of IL-17 family members to their corresponding receptors lead to modulation of antimicrobial functions of target cells including alveolar epithelial cells. Stimulated alveolar epithelial cells produce antimicrobial peptides and are involved in granulepoesis, neutrophil recruitment and tissue repair. Mucosal immunity mediated by Th17 cells is protective against numerous pulmonary pathogens including extracellular bacterial and fungal pathogens. This review focuses on the protective role of Th17 cells during pulmonary infection, highlighting subset differentiation, effector cytokines production, followed by study of the binding of these cytokines to their corresponding receptors, the subsequent signaling pathway they engender and their effector role in host defense.

A High Frequency of Peripheral Blood IL-22(+) CD4(+) T Cells in Patients With New Onset Type 2 Diabetes Mellitus

BACKGROUND

This study is aimed at investigating the frequency of different functional IL-22(+) CD4(+) T cells in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

The frequency of circulating IFN-γ+IL-17-IL-22-CD4(+) (Th1), IFN-γ-IL-17A+IL-22-CD4(+) (Th17), and IFN-γ-IL-17A-IL-22(+) CD4(+) (Th22), and other subsets of IL-22(+) CD4(+) T cells in 31 patients with new onset T2DM and 16 healthy controls was characterized by flow cytometry. The levels of serum IL-22, IL-17, IFN-γ, insulin C-peptide, hemoglobin A1c (HbA1c), fasting plasma glucose, and insulin were examined.

RESULTS

The frequency of Th1, Th17, Th22, IFN-γ(+) IL-17(-) IL-22(+) , and IFN-γ(-) IL-17(+) IL-22(+) CD4(+) T cells and the concentrations of IL-22, but not IL-17 and IFNγ, in the patients were significantly higher than controls. The percentages of Th22 cells were correlated positively with the frequency of IFN-γ(-) IL-17(+) IL-22(+) CD4(+) T cells, the values of body mass index (BMI) and homeostatic model assessment insulin resistance (HOMA-IR), and the levels of serum IL-22 in those patients.

CONCLUSION

Our data suggest that IL-22(+) CD4(+) T cells may contribute to the early process of T2DM.

IL-22BP is produced by eosinophils in human gut and blocks IL-22 protective actions during colitis

Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel diseases (IBDs), are characterized by high levels of IL-22 production. Rodent studies revealed that this cytokine is protective during colitis but whether this is true in IBDs is unclear. We show here that levels of the soluble inhibitor of IL-22, interleukin 22-binding protein (IL-22BP), are significantly enhanced during IBDs owing to increased numbers of IL-22BP-producing eosinophils, that we unexpectedly identify as the most abundant source of IL-22BP protein in human gut. In addition, using IL-22BP-deficient rats, we confirm that endogenous IL-22BP is effective at blocking protective actions of IL-22 during acute colitis. In conclusion, our study provides new important insights regarding the biology of IL-22 and IL-22BP in the gut and indicates that protective actions of IL-22 are likely to be suboptimal in IBDs thus making IL-22BP a new relevant therapeutic target.

IL-11 signaling as a therapeutic target for cancer

IL-11 is a member of the IL-6 family of cytokines. While it was discovered over 20 years ago, we have very little understanding of the role of IL-11 during normal homeostasis and disease. Recently, IL-11 has gained interest for its newly recognized role in the pathogenesis of diseases that are attributed to deregulated mucosal homeostasis, including gastrointestinal cancers. IL-11 can increase the tumorigenic capacity of cells, including survival of the cell or origin, proliferation of cancerous cells and survival of metastatic cells at distant organs. Here we outline our current understanding of IL-11 biology and recent advances in our understanding of its role in cancer. We advocate that inhibition of IL-11 signaling may represent an emerging therapeutic opportunity for numerous cancers.

IL-17a and IL-22 Induce Expression of Antimicrobials in Gastrointestinal Epithelial Cells and May Contribute to Epithelial Cell Defense against Helicobacter pylori

Helicobacter pylori colonization of the human stomach can lead to adverse clinical outcomes including gastritis, peptic ulcers, or gastric cancer. Current data suggest that in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization. Specifically, CD4+ T cell responses impact the pathology elicited in response to H. pylori. Because gastritis is believed to be the initiating host response to more detrimental pathological outcomes, there has been a significant interest in pro-inflammatory T cell cytokines, including the cytokines produced by T helper 17 cells. Th17 cells produce IL-17A, IL-17F, IL-21 and IL-22. While these cytokines have been linked to inflammation, IL-17A and IL-22 are also associated with anti-microbial responses and control of bacterial colonization. The goal of this research was to determine the role of IL-22 in activation of antimicrobial responses in models of H. pylori infection using human gastric epithelial cell lines and the mouse model of H. pylori infection. Our data indicate that IL-17A and IL-22 work synergistically to induce antimicrobials and chemokines such as IL-8, components of calprotectin (CP), lipocalin (LCN) and some β-defensins in both human and primary mouse gastric epithelial cells (GEC) and gastroids. Moreover, IL-22 and IL-17A-activated GECs were capable of inhibiting growth of H. pylori in vitro. While antimicrobials were activated by IL-17A and IL-22 in vitro, using a mouse model of H. pylori infection, the data herein indicate that IL-22 deficiency alone does not render mice more susceptible to infection, change their antimicrobial gene transcription, or significantly change their inflammatory response.

Th-17 regulatory cytokines inhibit corticosteroid induced airway structural cells apoptosis

Background

Although corticosteroid is a powerful anti-inflammatory drug that is used widely to control asthma, still severe asthmatics can develop steroid resistance. Airway fibroblasts are quite resistant to steroids during Idiopathic pulmonary fibrosis (IPF) and fibrosis in asthmatic lungs is not always controlled. Th-17 regulatory cytokine which are elevated in lung tissues of asthmatics were shown to enhance the survival of various types of cells. STAT factors are central to this anti-apoptotic function. However, it is not yet clear whether these cytokines contribute to steroid hypo-responsiveness in asthma. Therefore, in this study, we investigated the ability of Th-17 regulatory cytokines, specifically IL-21, IL22 and IL23, to protect structural airway cells against dexamethasone-induced apoptosis.

Methods

Primary human fibroblasts, ASM cells, and lung endothelial cells line were treated with IL-21, IL-22, and IL-23 cytokines before incubation with dexamethasone and the level of apoptosis was determined by measuring cellular Annexin-V using Flow cytometry.

Results

Our data indicated that treatment with Th-17 regulatory cytokines was effective in inhibiting induced apoptosis for both fibroblasts and endothelial cells but not ASM cells. STAT3 phosphorylation levels were also upregulated in fibroblasts and endothelial upon treatment with these cytokines. Interestingly, inhibiting STAT3 phosphorylation abrogated IL-21, IL-22, and IL-23 anti-apoptotic effect on fibroblasts and endothelial cells.

Conclusions

This data suggest that Th-17 regulatory cytokines may play a critical role in regulating the survival of fibroblasts during asthma, IPF as well as other chronic lung inflammatory diseases leading to enhanced fibrosis. Accordingly, findings of this paper may pave the way for more extensive research on the role of these regulatory cytokines in fibrosis development in various chronic inflammatory diseases.

Interleukin-22 Signaling in the Regulation of Intestinal Health and Disease

Interleukin (IL)-22 is a member of the IL-10 family of cytokines that has been extensively studied since its discovery in 2000. This review article aims to describe the cellular sources and signaling pathways of this cytokine as well as the functions of IL-22 in the intestine. In addition, this article describes the roles of IL-22 in the pathogenesis of several gastrointestinal diseases, including inhibition of inflammation and barrier defense against pathogens within the intestine. Since many of the functions of IL-22 in the intestine are incompletely understood, this review is meant to assess our current understanding of the roles of IL-22 and provide new opportunities for inquiry to improve human intestinal health and disease.

Interleukin-23 (IL-23), independent of IL-17 and IL-22, drives neutrophil recruitment and innate inflammation during Clostridium difficile colitis in mice

Our objective was to determine the role of the inflammatory cytokine interleukin-23 (IL-23) in promoting neutrophil recruitment, inflammatory cytokine expression and intestinal histopathology in response to Clostridium difficile infection. Wild-type (WT) and p19(-/-) (IL-23KO) mice were pre-treated with cefoperazone in their drinking water for 5 days, and after a 2-day recovery period were challenged with spores from C. difficile strain VPI 10463. Interleukin-23 deficiency was associated with significant defects in both the recruitment of CD11b(High) Ly6G(H) (igh) neutrophils to the colon and the expression of neutrophil chemoattractants and stabilization factors including Cxcl1, Cxcl2, Ccl3 and Csf3 within the colonic mucosa as compared with WT animals. Furthermore, the expression of inflammatory cytokines including Il33, Tnf and Il6 was significantly reduced in IL-23-deficient animals. There was also a trend towards less severe colonic histopathology in the absence of IL-23. The induction of Il17a and Il22 was also significantly abrogated in IL-23KO mice. Inflammatory cytokine expression and neutrophilic inflammation were not reduced in IL-17a-deficient mice or in mice treated with anti-IL-22 depleting monoclonal antibody. However, induction of RegIIIg was significantly reduced in animals treated with anti-IL-22 antibody. Taken together, these data indicate that IL-23, but not IL-17a or IL-22, promotes neutrophil recruitment and inflammatory cytokine and chemokine expression in the colon in response to C. difficile infection.

IL-22: a promising candidate to inhibit viral-induced liver disease progression and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a growing concern all over the world. With the number of patients rising exponentially with each passing day, HCC is a problem that needs immediate attention. Currently, available treatment strategies focus on controlling the damage after the development of HCC. The options available from chemo- and radio-embolization to surgical resection and transplantation are not efficacious as required due to the complex nature of the disease. Liver regeneration and tissue healing are the subject of great interest today. Interleukin-22 (IL-22) is a cytokine with the ability to regenerate and therefore reverse the injuries caused by a wide range of agents. IL-22 acts via STAT molecule and controls the activity of a wide variety of cell survival and proliferation genes. Experimental data has given a positive insight into the role of IL-22 in inhibition of viral and alcohol-induced hepatocellular carcinoma. A further insight into the nature of IL-22 and the factors that can be manipulated in controlling the activity of IL-22 can help to counter the menace caused by the devastating effects of HCC.

Role of distinct CD4(+) T helper subset in pathogenesis of oral lichen planus

Oral lichen planus (OLP) is one of the most common chronic inflammatory oral mucosal diseases with T-cell-mediated immune pathogenesis. In subepithelial and lamina propria of OLP local lesions, the presence of CD4(+) T helper (CD4(+) Th) cells appeared as the major lymphocytes. These CD4(+) T lymphocytes can differentiate into distinct Th cell types such as Th1, Th2, Treg, Th17, Th22, Th9, and Tfh within the context of certain cytokines environment. Growing evidence indicated that Th1/Th2 imbalance may greatly participate into the cytokine network of OLP immunopathology. In addition, Th1/Th2 imbalance can be regulated by the Treg subset and also greatly influenced by the emerging novel CD4(+) Th subset Th17. Furthermore, the presence of novel subsets Th22, Th9 and Tfh in OLP patients is yet to be clarified. All these Th subsets and their specific cytokines may play a critical role in determining the character, extent and duration of immune responses in OLP pathogenesis. Therefore, we review the roles of distinct CD4(+) Th subsets and their signature cytokines in determining disease severity and susceptibility of OLP and also reveal the novel therapeutic strategies based on T lymphocytes subsets in OLP treatment.

Differential Requirements for IL-17A and IL-22 in Cecal versus Colonic Inflammation Induced by Helicobacter hepaticus

Type 17 helper T-cell cytokines have been implicated in the pathogenesis of inflammatory bowel disease, a chronic condition affecting the gastrointestinal tract, but information regarding their contribution to pathology in different regions of the gut is lacking. By using a murine model of bacteria-induced typhlocolitis, we investigated the role of IL-17A, IL-17F, and IL-22 in cecal versus colonic inflammation. Cecal, but not colonic, pathology in C57BL/6 mice inoculated with Helicobacter hepaticus plus anti-IL-10 receptor (IL-10R) monoclonal antibody was exacerbated by co-administration of anti-IL-17A monoclonal antibody, suggesting a disease-protective role for IL-17A in the cecum. In contrast, anti-IL-17F had no effect on H. hepaticus-induced intestinal pathology. Neutralization of IL-22 prevented the development of colonic, but not cecal, inflammation in H. hepaticus-infected anti-IL-10R-treated mice, demonstrating a pathogenic role for IL-22 in the colon. Analysis of transcript levels revealed differential expression of IL-22R, IL-22 binding protein, and IL-23R between cecum and colon, a finding that may help explain why these tissues respond differently after anti-IL-22 treatment. Analysis of microarray data from healthy human intestine further revealed significant differences in cytokine receptor transcript levels (including IL-22RA1 and IL-23R) in distinct parts of the human gut. Together, our findings demonstrate that individual type 17 helper T-cell cytokines can have proinflammatory or anti-inflammatory effects in different regions of the intestine, an observation that may have implications for interventions against human inflammatory bowel disease.

Interleukin 19 reduces inflammation in chemically induced experimental colitis

Inflammatory bowel disease results from chronic dysregulation of the mucosal immune system and aberrant activation of both the innate and adaptive immune responses. Interleukin (IL)-19, a member of the IL-10 family, functions as an anti-inflammatory cytokine. Here, we investigated the contribution of IL-19 to intestinal inflammation in a model of T cell-mediated colitis in mice. Inflammatory responses in IL-19-deficient mice were assessed using the 2,4,6-trinitrobenzene sulfonic acid (TNBS) model of acute colitis. IL-19 deficiency aggravated TNBS-induced colitis and compromised intestinal recovery in mice. Additionally, the exacerbation of TNBS-induced colonic inflammation following genetic ablation of IL-19 was accompanied by increased production of interferon-gamma, IL-12 (p40), IL-17, IL-22, and IL-33, and decreased production of IL-4. Moreover, the exacerbation of colitis following IL-19 knockout was also accompanied by increased production of CXCL1, G-CSF and CCL5. Using this model of induced colitis, our results revealed the immunopathological relevance of IL-19 as an anti-inflammatory cytokine in intestinal inflammation in mice.

Pathogen Resistance Mediated by IL-22 Signaling at the Epithelial-Microbiota Interface

Intestinal colonization resistance to bacterial pathogens is generally associated, among other factors, with mucosal homeostasis that preserves the integrity of the intestinal barrier. Mucosal homeostasis depends on physical and molecular interactions between three components: the resident microbiota, the epithelial layer and the local immune system. The cytokine IL-22 helps to orchestrate this three-way interaction. IL-22 is produced by immune cells present beneath the epithelium and is induced by bacteria present in the intestine. IL-22 stimulates the epithelial cells via the IL-22RA1-IL-10R2 receptor complex inducing changes in the expression of genes involved in the maintenance of epithelial barrier integrity, with a variety of functions in pathogen resistance such as mucus layer modifications and hydration, tight junction fortification and the production of a broad range of bactericidal compounds. These mechanisms of pathogen resistance, in turn, affect the microbiota composition and create an environment that excludes pathogens. Here we highlight the role of IL-22 as key mediator in the give-and-take relationship between the microbiota and the host that impacts pathogen resistance.

Association between interleukin-22 genetic polymorphisms and bladder cancer risk

OBJECTIVE

The cytokine interleukin-22 (IL-22), which is produced by T cells and natural killer cells, is associated with tumorigenesis and tumor progression in cancers. However, the role of IL-22 in bladder cancer has not been investigated.

MATERIALS AND METHODS

A prospective hospital-based case-control study comprising 210 patients with pathologically proven bladder cancer and 210 age- and gender-matched healthy controls was conducted. The genotypes of 3 common polymorphisms (-429 C/T, +1046 T/A and +1995 A/C) of the IL-22 gene were determined with fluorogenic 5' exonuclease assays.

RESULTS

Patients with bladder cancer had a significantly higher frequency of the IL-22 -429 TT genotype [odds ratio (OR)=2.04, 95% confidence interval (CI)=1.19, 3.49; p=0.009] and -429 T allele (OR=1.42, 95% CI=1.08, 1.87; p=0.01) than the healthy controls. These findings were still significant after a Bonferroni correction. When stratifying according to the stage of bladder cancer, we found that patients with superficial bladder cancer had a significantly lower frequency of the IL-22 -429 TT genotype (OR=0.48, 95% CI=0.23, 0.98; p=0.04). When stratifying according to the grade and histological type of bladder cancer, we found no statistical association. The IL-22 +1046 T/A and IL-22 +1995 A/C gene polymorphisms were not associated with the risk of bladder cancer.

CONCLUSION

To the authors' knowledge, this is the first report documenting that the IL-22 -429 C/T gene polymorphism is associated with bladder cancer risk. Additional studies are required to confirm this finding.

Exploring the role of interleukin-22 in neurological and autoimmune disorders

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family that has recently gained attention in regard to its recognized pathogenic role in neurological and autoimmune disorders. The pathological involvement of IL-22 has been linked to Th17 cells that are involved in its production. Its biological activity results from its ability to bind to a heterodimeric receptor consisting of IL-22 receptor 1 (IL-22R1) and IL-10R2. Emerging evidence has identified IL-22 involvement in neurological diseases and autoimmune disorders such as Guillain-Barré Syndrome (GBS), multiple sclerosis (MS), Alzheimer's disease (AD), encephalitis, inflammatory myopathies, myasthenia gravis (MG), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS), psoriasis and Crohn's disease (CD). However, the biological activity of IL-22 is variable resulting in protective or pathogenic effects in different disease states. As such, the development of therapeutic targeting strategies to modify the biological activity of IL-22 is being explored as a promising interventional approach to treat neurological and autoimmune diseases.

Th22 cells control colon tumorigenesis through STAT3 and Polycomb Repression complex 2 signaling

Th22 cells traffic to and retain in the colon cancer microenvironment, and target core stem cell genes and promote colon cancer stemness via STAT3 and H3K79me2 signaling pathway and contribute to colon carcinogenesis. However, whether Th22 cells affect colon cancer cell proliferation and apoptosis remains unknown. We studied the interaction between Th22 cells and colon cancer cells in the colon cancer microenvironment. Colon cancer proliferation was examined by flow cytometry analysis and H(3) thymidine incorporation. Cell cycle related genes were quantified by real-time PCR and Western blotting. We transfected colon cancer cells with lentiviral vector encoding specific gene shRNAs and used chromatin immunoprecipitation (ChIP) assay to determine the genetic signaling involved in interleukin (IL)-22-mediated colon cancer cell proliferation. We showed that Th22 cells released IL-22 and stimulated colon cancer proliferation. Mechanistically, IL-22 activated STAT3, and subsequently STAT3 bound to the promoter areas of the Polycomb Repression complex 2 (PRC2) components SUZ12 and EED, and stimulated the expression of PRC2. Consequently, the activated PRC2 catalyzed the promoters of the cell cycle check-point genes p16 and p21, and inhibited their expression through H3K27me3-mediated histone methylation, and ultimately caused colon cancer cell proliferation. Bioinformatics analysis revealed that the levels of IL-22 expression positively correlated with the levels of genes controlling cancer proliferation and cell cycling in colon cancer. In addition to controlling colon cancer stemness, Th22 cells support colon carcinogenesis via affecting colon cancer cell proliferation through a distinct histone modification.

GPx2 Induction Is Mediated Through STAT Transcription Factors During Acute Colitis

BACKGROUND

The selenoprotein glutathione peroxidase 2 (GPx2) is highly expressed in the gastrointestinal epithelium. During inflammatory bowel disease and colorectal cancer, GPx2 expression is enhanced.

METHODS

We analyzed GPx2 expression and transcriptional regulation during the different phases of dextran sulfate sodium (DSS)-induced colitis in mice and in cytokine-treated colorectal cancer cells.

RESULTS

In the colon of DSS-treated mice, GPx2 was upregulated during the acute and recovery phase. In the latter, it was specifically localized in regenerating ki67-positive crypts next to ulcerations. In cultured cells, endogenous GPx2 expression and GPx2 promoter activity were enhanced by the anti-inflammatory mediators 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) and interleukin-22 (IL-22), while it was unaffected by classical proinflammatory cytokines like IL-1β. Induction of GPx2 expression by 15d-PGJ2 was mediated through Nrf2. In contrast, in DSS-treated Nrf2-KO mice GPx2 expression remained upregulated during recovery, which appeared to be independent of Nrf2. IL-22 activates transcription factors of the signal transducers and activators of transcription (STAT) family. Therefore, we analyzed the GPx2 promoter for putative STAT-responsive elements and identified 4 of them. Point mutation of the binding element next to the transcription start completely abolished promoter activation after IL-22 treatment and after cotransfection of STAT expression plasmids. To show in vivo relevance of the obtained results, we performed immunohistochemistry for phospho-STAT3 and GPx2. Especially during acute colitis, GPx2 and nuclear STAT3 colocalized in inflamed areas.

CONCLUSIONS

GPx2 is a novel target of STAT transcription factors. The upregulation of GPx2 by IL-22 indicates that GPx2 might be important for the resolution of inflammation.

A pro-inflammatory role for Th22 cells in Helicobacter pylori-associated gastritis

OBJECTIVE

Helper T (Th) cell responses are critical for the pathogenesis of Helicobacter pylori-induced gastritis. Th22 cells represent a newly discovered Th cell subset, but their relevance to H. pylori-induced gastritis is unknown.

DESIGN

Flow cytometry, real-time PCR and ELISA analyses were performed to examine cell, protein and transcript levels in gastric samples from patients and mice infected with H. pylori. Gastric tissues from interleukin (IL)-22-deficient and wild-type (control) mice were also examined. Tissue inflammation was determined for pro-inflammatory cell infiltration and pro-inflammatory protein production. Gastric epithelial cells and myeloid-derived suppressor cells (MDSC) were isolated, stimulated and/or cultured for Th22 cell function assays.

RESULTS

Th22 cells accumulated in gastric mucosa of both patients and mice infected with H. pylori. Th22 cell polarisation was promoted via the production of IL-23 by dendritic cells (DC) during H. pylori infection, and resulted in increased inflammation within the gastric mucosa. This inflammation was characterised by the CXCR2-dependent influx of MDSCs, whose migration was induced via the IL-22-dependent production of CXCL2 by gastric epithelial cells. Under the influence of IL-22, MDSCs, in turn, produced pro-inflammatory proteins, such as S100A8 and S100A9, and suppressed Th1 cell responses, thereby contributing to the development of H. pylori-associated gastritis.

CONCLUSIONS

This study, therefore, identifies a novel regulatory network involving H. pylori, DCs, Th22 cells, gastric epithelial cells and MDSCs, which collectively exert a pro-inflammatory effect within the gastric microenvironment. Efforts to inhibit this Th22-dependent pathway may therefore prove a valuable strategy in the therapy of H. pylori-associated gastritis.

Immunoregulatory Pathways Involved in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) include ulcerative colitis and Crohn's disease. The immune response in ulcerative colitis is different from the Crohn's disease. Accumulating evidence suggests that IBD results from an inappropriate inflammatory response to intestinal microbes in a genetically susceptible host. Several immunoregulatory abnormalities have been reported in patients with IBD, including the ratio of proinflammatory (tumor necrosis factor alpha, IL-6, IL-1-β) to immunoregulatory cytokines (IL-10, TGF-β, IL-35) and selective activation of T-helper (Th) lymphocyte subsets (Th1, Th2, Th9, Th17, and regulatory T cells). The purpose of this review is to show the immunoregulatory pathways (regulatory cells and cytokines) involved in IBD published in recent years.

IL-22 regulates lymphoid chemokine production and assembly of tertiary lymphoid organs

The series of events leading to tertiary lymphoid organ (TLO) formation in mucosal organs following tissue damage remain unclear. Using a virus-induced model of autoantibody formation in the salivary glands of adult mice, we demonstrate that IL-22 provides a mechanistic link between mucosal infection, B-cell recruitment, and humoral autoimmunity. IL-22 receptor engagement is necessary and sufficient to promote differential expression of chemokine (C-X-C motif) ligand 12 and chemokine (C-X-C motif) ligand 13 in epithelial and fibroblastic stromal cells that, in turn, is pivotal for B-cell recruitment and organization of the TLOs. Accordingly, genetic and therapeutic blockade of IL-22 impairs and reverses TLO formation and autoantibody production. Our work highlights a critical role for IL-22 in TLO-induced pathology and provides a rationale for the use of IL-22-blocking agents in B-cell-mediated autoimmune conditions.

Three-Dimensional Micro-Computed Tomography Analyses of Induced Periapical Lesions in Transgenic Mice

The aim of this study was to evaluate the three-dimensional (3D) parameters given by the micro-computed tomography (µCT) analysis of experimentally induced periapical lesions in wild type (WT) and knockout mice for the interleukin 22 (IL-22 KO). Periapical lesions were induced in the mandibular first molars of wild type and IL-22 KO mice (n = 12 teeth/group). The animals were euthanized after the experimental periods of 7, 21 and 42 days. The mandibles were removed and exposed to µCT scanning. The analyses were performed by the CTAn software for the tree-dimensional parameters: Tissue Volume (TV), Lesion Volume (LV), Tissue Surface (TS), Lesion Surface (LS), Intersection Surface (IS), and Trabecular Pattern factor (Tb.Pf). After that, the tissue was subjected to routine histologic procedures and to immunohistochemistry analysis. Statistical analysis was performed in the GraphPad software. A t-test was used to compare the differences between the groups with significance level of 5%. The evaluation of the 3D parameters showed statistical significant difference between the groups only at the latest period of periapical lesion development (42 days), for the TV, LV, TS, LS and IS parameters. The immunohistochemistry evaluation confirmed the immunostaining for IL-22 only in the WT mice, surrounding the periapical lesion. There were no differences regarding the trabecular alveolar bone (Tb.Pf) that could influence the lesion development. In conclusion, the 3D parameters showed that the absence of IL-22 leads to detectable differences at 42 days of lesion progression, resulting in smaller periapical lesions.

The role of Th17-associated cytokines in the pathogenesis of experimental autoimmune uveitis (EAU)

The proinflammatory and pathogenic function of Th17 cells in autoimmune diseases have been established but the mechanism by which such cells cause disease remains to be determined. Inflammatory cytokines produced by Th17 cells may either promote or inhibit disease development. The major cytokines produced by the uveitogenic T cells, such as IL-17 and IL-22, are not always pathogenic, and the disease-inducing ability of pathogenic T cells is not immediately correlated to the amount of cytokine they produce. Future studies identifying factors causing increased Th17 responses and determining the types of cells that regulating Th17 autoreactive T cells should facilitate our effort of understanding Th17-mediated disease pathogenesis.

IL10R2 Overexpression Promotes IL22/STAT3 Signaling in Colorectal Carcinogenesis

The mucosal immune response in the setting of intestinal inflammation contributes to colorectal cancer. IL10 signaling has a central role in gut homeostasis and is impaired in inflammatory bowel disease (IBD). Out of two IL10 receptor subunits, IL10R1 and IL10R2, the latter is shared among the IL10 family of cytokines and activates STAT signaling. STAT3 is oncogenic in colorectal cancer; however, knowledge about IL10 signaling upstream of STAT3 in colorectal cancer is lacking. Here, expression of IL10 signaling genes was examined in matched pairs from normal and tumor tissue from colorectal cancer patients showing overexpression (mRNA, protein) of IL10R2 and STAT3 but not IL10R1. IL10R2 overexpression was related to microsatellite stability. Transient overexpression of IL10R2 in HT29 cells increased proliferation upon ligand activation (IL10 and IL22). IL22, and not IL10, phosphorylated STAT3 along with increased phosphorylation of AKT and ERK. A significantly higher expression of IL22R1 and IL10R2 was also confirmed in a separate cohort of colorectal cancer samples. IL22 expression was elevated in gut mucosa from patients with IBD and colitis-associated cancer, which also exhibited increased expression of IL22R1 but not its coreceptor IL10R2. Overall, these data indicate that overexpression of IL10R2 and STAT3 contributes to colorectal carcinogenesis in microsatellite-stable tumors through IL22/STAT3 signaling.

Fibrosis Related Inflammatory Mediators: Role of the IL-10 Cytokine Family

Importance of chronic fibroproliferative diseases (FDs) including pulmonary fibrosis, chronic kidney diseases, inflammatory bowel disease, and cardiovascular or liver fibrosis is rapidly increasing and they have become a major public health problem. According to some estimates about 45% of all deaths are attributed to FDs in the developed world. Independently of their etiology the common hallmark of FDs is chronic inflammation. Infiltrating immune cells, endothelial, epithelial, and other resident cells of the injured organ release an orchestra of inflammatory mediators, which stimulate the proliferation and excessive extracellular matrix (ECM) production of myofibroblasts, the effector cells of organ fibrosis. Abnormal amount of ECM disturbs the original organ architecture leading to the decline of function. Although our knowledge is rapidly expanding, we still have neither a diagnostic tool to detect nor a drug to specifically target fibrosis. Therefore, there is an urgent need for the more comprehensive understanding of the pathomechanism of fibrosis and development of novel diagnostic and therapeutic strategies. In the present review we provide an overview of the common key mediators of organ fibrosis highlighting the role of interleukin-10 (IL-10) cytokine family members (IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26), which recently came into focus as tissue remodeling-related inflammatory cytokines.

High-resolution gene expression profiling using RNA sequencing in patients with inflammatory bowel disease and in mouse models of colitis

BACKGROUND AND AIMS

Proper interpretation of data from preclinical animal studies requires thorough knowledge of the pathophysiology of both the human disease and animal models. In this study, the expression of inflammatory bowel disease [IBD]-associated genes was characterised in mouse models of colitis to examine the underlying molecular pathways and assess the similarity between the experimental models and human disease.

METHODS

RNA sequencing was performed on colon biopsies from Crohn's disease [CD] patients, ulcerative colitis [UC] patients and non-IBD controls. Genes shown to be significantly dysregulated in human IBD were used to study gene expression in colons from a piroxicam-accelerated colitis interleukin-10 knockout [PAC IL-10 k.o.], an adoptive transfer [AdTr] and a dextran sulfate sodium [DSS] colitis mouse model.

RESULTS

Of 115 literature-defined genes linked to IBD, 92 were significantly differentially expressed in inflamed mucosa of CD and/or UC patients compared with non-IBD controls. The most upregulated genes were shared by both diseases, including REG1A, LCN2, NOS2, CXCL1-2, and S100A9. Of those 92 IBD-associated genes, 71 [77%] were significantly dysregulated in PAC IL-10 k.o. mice, whereas 59 [64%] were significantly dysregulated in AdTr mice compared with wild-type controls. Some of the most upregulated genes, including S100a8-9, Nos2, and Lcn2, were shared by the colitis models and correlated with disease activity.

CONCLUSIONS

IBD and experimental murine colitis have a high degree of similarity in the colonic transcriptional profile, probably secondary to non-specific inflammatory processes. However, differences do exist between models, emphasising the need for careful selection and interpretation of qualified animal models in preclinical research.

Interleukin-22 activates JAK-STAT3 pathway: Role in liver disease

Interleukin (IL)-22 belongs to the IL-10 family and is secreted mainly by Th22 cells. IL-22 binds to IL-22 receptors which are expressed in special tissues and cells, and activates the signal transducer and activator of transcription 3 (STAT3) signal pathway. IL-22 has a role in liver injury primarily through activating the STAT3 signal pathway. In different types of liver injury, IL-22 protects the liver or aggravates liver injury. This paper will review the role of IL-22 in liver disease in terms of activating the STAT3 signal pathway.

Interleukin-22 in kidney injury and regeneration

Interleukins have become well-known regulators of innate and adaptive immunity-related tissue inflammation. Recently, IL-22 has gained a lot of interest for its unique functions in maintaining and regaining epithelial integrity. IL-22 is exclusively secreted by different immune cell subsets, while IL-22 receptors are mainly expressed by epithelial cells. As the kidney is largely an epithelial organ, the functional role of IL-22 in the kidney deserves to be explored in detail. Here, we briefly summarize the key features of IL-22 biology and review the available data on its expression and functional roles in kidney injury and kidney regeneration. Furthermore, we provide suggestions on how to explore this evolving field in the future.

Up-regulation of interleukin-22 mediates liver fibrosis via activating hepatic stellate cells in patients with hepatitis C

Interleukin-22 (IL-22) is known to play a critical role in liver immunity. However, the role of IL-22 in HCV-associated liver fibrosis is poorly understood. In this study, patients with HCV infection disclosed significant increases in peripheral numbers of IL-22-producing cells as well as in IL-22 plasma levels. In the liver, the increased intrahepatic IL-22(+) cells were positively correlated with fibrotic staging scores and clinical progression from CHC to cirrhosis. Moreover, the majority of IL-22(+) cells were located in fibrotic areas in the liver of patients with cirrhosis and co-localized with α-smooth muscle actin (α-SMA) positive hepatic stellate cells (HSCs). In vitro, administration of IL-22 was accompanied with inhibited LX-2 cell apoptosis, promoted LX-2 cell proliferation, increased expression of α-SMA, and up-regulated collagen production by LX-2 cells. Collectively, our data provide evidence that IL-22 may contribute to the fibrogenesis of HCV-associated liver fibrosis by activating HSCs.

STAT3-Activating Cytokines: A Therapeutic Opportunity for Inflammatory Bowel Disease?

The gastrointestinal tract is lined by a single layer of epithelial cells that secrete mucus toward the lumen, which collectively separates the immune sentinels in the underlying lamina propria from the intestinal microflora to prevent aberrant immune responses. Inflammatory bowel disease (IBD) describes a group of autoimmune diseases that arise from defects in epithelial barrier function and, as a consequence, aberrant production of inflammatory cytokines. Among these, interleukin (IL)-6, IL-11, and IL-22 are elevated in human IBD patients and corresponding mouse models and, through activation of the JAK/STAT3 pathway, can both propagate and ameliorate disease. In particular, cytokine-mediated activation of STAT3 in the epithelial lining cells affords cellular protection, survival, and proliferation, thereby affording therapeutic opportunities for the prevention and treatment of colitis. In this review, we focus on recent insights gained from therapeutic modulation of the activities of IL-6, IL-11, and IL-22 in models of IBD and advocate a cautionary approach with these cytokines to minimize their tumor-promoting activities on neoplastic epithelium.

Claudin-2 as a mediator of leaky gut barrier during intestinal inflammation

The epithelial tight junction determines the paracellular water and ion movement in the intestine and also prevents uptake of larger molecules, including antigens, in an uncontrolled manner. Claudin-2, one of the 27 mammalian claudins regulating that barrier function, forms a paracellular channel for small cations and water. It is typically expressed in leaky epithelia like proximal nephron and small intestine and provides a major pathway for the paracellular transport of sodium, potassium, and fluid. In intestinal inflammation (Crohn's disease, ulcerative colitis), immune-mediated diseases (celiac disease), and infections (HIV enteropathy), claudin-2 is upregulated in small and large intestine and contributes to diarrhea via a leak flux mechanism. In parallel to that upregulation, other epithelial and tight junctional features are altered and the luminal uptake of antigenic macromolecules is enhanced, for which claudin-2 may be partially responsible through induction of tight junction strand discontinuities.

Pathogenesis of Crohn's disease

Significant progress in our understanding of Crohn's disease (CD), an archetypal common, complex disease, has now been achieved. Our ability to interrogate the deep complexities of the biological processes involved in maintaining gut mucosal homeostasis is a major over-riding factor underpinning this rapid progress. Key studies now offer many novel and expansive insights into the interacting roles of genetic susceptibility, immune function, and the gut microbiota in CD. Here, we provide overviews of these recent advances and new mechanistic themes, and address the challenges and prospects for translation from concept to clinic.

Effect of IL-22 on expression of intestinal trefoil factor in intestinal epithelial cells

AIM: To investigate the effect of interleukin-22 (IL-22) on the intestinal trefoil factor (ITF/TFF3) expression in IEC-6 cells and discuss the possible mechanism.

METHODS: IEC-6 cells were treated with IL-22 at different concentrations (1, 10, or 100 ng/mL) for 12, 24, or 48 h. The mRNA expression of TFF3, signal transducer and activator of transcription 3 (STAT3), STAT6 and nuclear factor-κB (NF-κB) in IEC-6 cells was measured by RT-PCR.

RESULTS: The mRNA expression of TFF3 and STAT3 in IEC-6 cells treated with 1 ng/mL IL-22 was not significantly up-regulated when incubated for 0, 12, 24 or 48 h (P > 0.05). With time increasing, the mRNA expression of TFF3 in IEC-6 cells treated with 10 ng/mL IL-22 increased and the comparison between any two time points of 0, 12, 24 and 48 h showed significant differences (P < 0.05) except the comparison between the time points of 12 and 24 h; the mRNA expression of STAT3 also increased, and there were significant differences in any two time points (P < 0.05), except between 0 and 12 h (P > 0.05). When treated with 100 ng/mL IL-22, the mRNA expression of TFF3 in IEC-6 cells showed obvious up-regulation with time increasing, and the comparison between any two time points was statistically different (P < 0.05); the relationship between the mRNA expression of STAT3 and treatment time was the same as the group of 10 ng/mL. When IEC-6 cells were treated for 12 h, the mRNA expression of TFF3 was significantly higher in the 100 ng/mL group compared with the 1 ng/mL and 10 ng/mL groups (P < 0.05), although there was no statistical difference between the groups of 1 ng/mL and 10 ng/mL; the mRNA expression of STAT3 did not show a statistical difference (P > 0.05). The mRNA expression of TFF3 in IEC-6 cells for 24 and 48 h was significantly up-regulated as the concentration of IL-22 increased, and the comparison between any two concentrations of IL-22 showed a significant difference (P < 0.05); the mRNA expression of STAT3 was also up-regulated, showing a significant difference between any two concentrations of IL-22 except the comparison between the groups of 10 ng/mL and 100 ng/mL. We could not measure the expression of STAT6 mRNA, and the mRNA expression of NF-κB did not show a significant difference among the groups (P > 0.05).

CONCLUSION: IL-22 may up-regulate the mRNA expression of TFF3 in IEC-6 cells through the STAT3 signal transduction pathway in a time- and dose-dependent fashion.

Cytokine crowdsourcing: multicellular production of TH17-associated cytokines

In the 2 decades since its discovery, IL-17A has become appreciated for mounting robust, protective responses against bacterial and fungal pathogens. When improperly regulated, however, IL-17A can play a profoundly pathogenic role in perpetuating inflammation and has been linked to a wide variety of debilitating diseases. IL-17A is often present in a composite milieu that includes cytokines produced by TH17 cells (i.e., IL-17F, IL-21, IL-22, and IL-26) or associated with other T cell lineages (e.g., IFN-γ). These combinatorial effects add mechanistic complexity and more importantly, contribute differentially to disease outcome. Whereas TH17 cells are among the best-understood cell types that secrete IL-17A, they are frequently neither the earliest nor dominant producers. Indeed, non-TH17 cell sources of IL-17A can dramatically alter the course and severity of inflammatory episodes. The dissection of the temporal regulation of TH17-associated cytokines and the resulting net signaling outcomes will be critical toward understanding the increasingly intricate role of IL-17A and TH17-associated cytokines in disease, informing our therapeutic decisions. Herein, we discuss important non-TH17 cell sources of IL-17A and other TH17-associated cytokines relevant to inflammatory events in mucosal tissues.

Interleukin-22: immunobiology and pathology

Interleukin-22 (IL-22) is a recently described IL-10 family cytokine that is produced by T helper (Th) 17 cells, γδ T cells, NKT cells, and newly described innate lymphoid cells (ILCs). Knowledge of IL-22 biology has evolved rapidly since its discovery in 2000, and a role for IL-22 has been identified in numerous tissues, including the intestines, lung, liver, kidney, thymus, pancreas, and skin. IL-22 primarily targets nonhematopoietic epithelial and stromal cells, where it can promote proliferation and play a role in tissue regeneration. In addition, IL-22 regulates host defense at barrier surfaces. However, IL-22 has also been linked to several conditions involving inflammatory tissue pathology. In this review, we assess the current understanding of this cytokine, including its physiologic and pathologic effects on epithelial cell function.

Th17 differentiation and their pro-inflammation function

CD4(+) T helper cells are classical but constantly reinterpreted T-cell subset, playing critical roles in a diverse range of inflammatory responses or diseases. Depending on the cytokines they release and the immune responses they mediate, CD4(+) T cells are classically divided into two major cell populations: Th1 and Th2 cells. However, recent studies challenged this Th1/Th2 paradigm by discovering several T-helper cell subsets with specific differentiation program and functions, including Th17 cells, Treg cells, and Tfh cells. In this chapter, we summarize the current understanding and recent progresses on the Th17 lineage differentiation and its effector impacts on variety of inflammatory responses or disease pathogenesis.

Rocking media over ex vivo corneas improves this model and allows the study of the effect of proinflammatory cytokines on wound healing

PURPOSE

The aim of this work was to develop an in vitro cornea model to study the effect of proinflammatory cytokines on wound healing.

METHODS

Initial studies investigated how to maintain the ex vivo models for up to 4 weeks without loss of epithelium. To study the effect of cytokines, corneas were cultured with the interleukins IL-17A, IL-22, or a combination of IL-17A and IL-22, or lipopolysaccharide (LPS). The effect of IL-17A on wound healing was then examined.

RESULTS

With static culture conditions, organ cultures deteriorated within 2 weeks. With gentle rocking of media over the corneas and carbon dioxide perfusion, the ex vivo models survived for up to 4 weeks without loss of epithelium. The cytokine that caused the most damage to the cornea was IL-17A. Under static conditions, wound healing of the central corneal epithelium occurred within 9 days, but only a single-layered epithelium formed whether the cornea was exposed to IL-17A or not. With rocking of media gently over the corneas, a multilayered epithelium was achieved 9 days after wounding. In the presence of IL-17A, however, there was no wound healing evident. Characterization of the cells showed that wherever epithelium was present, both differentiated cells and highly proliferative cells were present.

CONCLUSIONS

We propose that introducing rocking to extend the effective working life of this model and the introduction of IL-17A to this model to induce aspects of inflammation extend its usefulness to study the effects of agents that influence corneal regeneration under normal and inflamed conditions.

Dendritic cell-epithelial cell crosstalk in the gut

Intestinal epithelial cells are fundamental to maintain barrier integrity and to participate in food degradation and absorption, but they can also decipher signals coming from the outside world and 'educate' the immune system accordingly. In particular, they interact with dendritic cells (DCs) and other intraepithelial immune cells to drive tolerogenic responses under steady state, but they can also release immune mediators to recruit inflammatory cells and to elicit immunity to infectious agents. When these interactions are deregulated, immune disorders can develop. In this review, we discuss some important features of epithelial cells and DCs and their fruitful interactions.

IL-15 suppresses colitis-associated colon carcinogenesis by inducing antitumor immunity

IL-15 regulates the development, survival, and proliferation of multiple innate and adaptive immune cells and plays a dual role, inducing both tumor cell growth and antitumor immunity. However, the role of IL-15 in inflammation-induced cancer remains unclear. To explore this, we have compared the colon carcinoma burden of Il15^-/- and Il15rα ^-/- mice with wild type (WT) mice after induction of colitis-associated colon carcinogenesis utilizing the AOM/DSS model. Compared to WT mice, Il15^-/- but not Il15rα ^-/- mice showed reduced survival, along with higher tumor incidence, colon weight, and tumor size. This suggests that low affinity IL-15 signaling via the shared IL-2Rβ/γc decreases the risk for developing colitis-associated cancer. CD11c-Il15 mice, in which IL-15 expression is reconstituted in Il15^-/- mice under the control of the CD11c-promoter, showed that selective reconstitution of IL-15 in antigen-presenting cells restored the CD8⁺ T and NK cell compartments, serum levels of IFNγ, G-CSF, IL-10, and CXCL1 and reduced tumor burden. After demonstrating IL-15 expression in human colorectal cancer (CRC) cells in situ, we investigated the role of this cytokine in the modulation of key colonic oncogenic pathways in the tumor. While these pathways were found to be unaltered in the absence of IL-15, tumor transcriptome analysis showed that the loss of IL-15 upregulates key inflammatory mediators associated with colon cancer progression, such as IL-1β, IL-22, IL-23, Cxcl5, and Spp1. These findings provide evidence that IL-15 suppresses colitis-associated colon carcinogenesis through regulation of antitumor cytotoxicity, and modulation of the inflammatory tumor micromilieu.

Role of interleukin-22 in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease thought to be mediated by the microbiota of the intestinal lumen and inappropriate immune responses. Aberrant immune responses can cause secretion of harmful cytokines that destroy the epithelium of the gastrointestinal tract, leading to further inflammation. Interleukin (IL)-22 is a member of the IL-10 family of cytokines that was recently discovered to be mainly produced by both adaptive and innate immune cells. Several cytokines and many of the transcriptional factors and T regulatory cells are known to regulate IL-22 expression through activation of signal transducer and activator of transcription 3 signaling cascades. This cytokine induces antimicrobial molecules and proliferative and antiapoptotic pathways, which help prevent tissue damage and aid in its repair. All of these processes play a beneficial role in IBD by enhancing intestinal barrier integrity and epithelial innate immunity. In this review, we discuss recent progress in the involvement of IL-22 in the pathogenesis of IBD, as well as its therapeutic potential.

The IL-20 subfamily of cytokines--from host defence to tissue homeostasis

The interleukin-20 (IL-20) subfamily of cytokines comprises IL-19, IL-20, IL-22, IL-24 and IL-26. These cytokines are all members of the larger IL-10 family, but have been grouped together to form the IL-20 subfamily based on their usage of common receptor subunits and similarities in their target-cell profiles and biological functions. Members of the IL-20 subfamily facilitate the communication between leukocytes and epithelial cells, thereby enhancing innate defence mechanisms and tissue repair processes at epithelial surfaces. In this Review, we describe the cellular sources and targets of the IL-20 subfamily cytokines, and we detail how their expression is regulated. Much of our understanding of the unique biology of this group of cytokines is still based on IL-22, which is the most studied member of the IL-20 subfamily. Nevertheless, we attempt a broader discussion of the emerging functions of IL-20 subfamily cytokines in host defence, inflammatory diseases, cancer and metabolism.

IL-22 enhances CCL20 production in IL-1β-stimulated human gingival fibroblasts

CC chemokine ligand 20 (CCL20) is involved in the recruitment of Th17 cells and thus in the exacerbation of periodontal disease, but the effect of simultaneous interleukin (IL)-22 and IL-1β stimulation on CCL20 production in human gingival fibroblasts (HGFs) is uncertain. In this study, we investigated the mechanisms of IL-1β- and/or IL-22-induced CCL20 production in HGFs. A single stimulation of IL-22 could not induce CCL20 production. On the other hand, IL-22 could increase CCL20 production from IL-1β-stimulated HGFs in a dose-dependent manner. C-Jun N terminal kinase (JNK) and inhibitor of nuclear factor κB (IκB)-α phosphorylation were increased in IL-1β- and IL-22-stimulated HGFs. An inhibitor of nuclear factor (NF)-κB decreased IL-1β- and IL-22-induced CCL20 production, though an inhibitor of JNK did not modulate CCL20 production. These data suggest that IL-1β in cooperation with IL-22 could increase Th17 cell accumulation in periodontally diseased tissues to enhance CCL20 production in HGFs.

IL-22 fate reporter reveals origin and control of IL-22 production in homeostasis and infection

IL-22 is a cytokine that regulates tissue homeostasis at barrier surfaces. A variety of IL-22-producing cell types is known, but identification on the single-cell level remains difficult. Therefore, we generated a fate reporter mouse that would allow the identification of IL-22-producing cells and their fate mapping in vivo. To trace IL-22-expressing cells, a sequence encoding Cre recombinase was cloned into the Il22 locus, and IL22(Cre) mice were crossed with reporter mice expressing enhanced yellow fluorescence protein (eYFP) under control of the endogenous Rosa26 promoter. In IL22(Cre)R26R(eYFP) mice, the fluorescent reporter permanently labels cells that have switched on Il22 expression, irrespective of cytokine production. Despite a degree of underreporting, eYFP expression was detectable in nonimmune mice and restricted to group 3 innate lymphoid cells (ILC3) in the gut and γδ T cells in skin or lung. Upon skin challenge with imiquimod, eYFP(+) γδ and CD4 T cells expanded in the skin. Infection with Citrobacter rodentium initially was controlled by ILC3, followed by expansion of eYFP(+) CD4 T cells, which were induced in innate lymphoid follicles in the colon. No eYFP expression was detected in small intestinal Th17 cells, and they did not expand in the immune response. Colonic eYFP(+) CD4 T cells exhibited plasticity during infection with expression of additional cytokines, in contrast to ILC3, which remained largely stable. Single-cell quantitative PCR analysis of eYFP(+) CD4 T cells confirmed their heterogeneity, suggesting that IL-22 expression is not confined to particular subsets or a dedicated Th22 subset.

Elevated levels of Th17 cells and Th17-related cytokines are associated with disease activity in patients with inflammatory bowel disease

OBJECTIVE

Interleukin-17(IL-17)-producing T helper(Th)17 cells are considered as a new subset of cells critical to the development of inflammatory bowel disease (IBD). We aimed to investigate the distribution of Th17 cells, the expressions of Th17-related cytokines (IL-17, IL-21 and IL-22) and their association with disease activity in IBD patients.

METHODS

We collected intestinal tissue biopsies from 40 patients with active ulcerative colitis (UC), 20 patients with active Crohn's disease (CD) and 20 healthy controls. The distribution of Th17 cells and expressions of Th17-related cytokines in colonic tissues were evaluated by a standard immunohistochemical procedure. Serum IL-17, IL-21 and IL-22 levels were determined by ELISA. Pearson's and Spearman's correlation analyses were performed to analyze the correlation between the number of Th17 cells, the expressions of Th17-related cytokines and disease activity index, endoscopic and histological grading, and CRP and PLT levels, respectively.

RESULTS

Compared with healthy controls, the number of Th17 cells and the expressions of IL-17, IL-21 and IL-22 were significantly increased in active IBD patients (P < 0.05). In addition, Pearson's and Spearman's correlation analyses showed that the number of Th17 cells and the expressions of Th17-related cytokines were correlated with disease activity index, endoscopic and histological grading, CRP and PLT levels (P < 0.05).

CONCLUSIONS

Th17 cells and Th17-related cytokines (IL-17, IL-21 and IL-22) were increased in the intestinal mucosa in active IBD patients and may play an important role in disease activity and mucosal damage.

Association of the interleukin-22 genetic polymorphisms with ulcerative colitis

BACKGROUND

Interleukin-22 (IL-22) is a member of the IL-10 family of anti-inflammatory cytokines that mediates epithelial immunity. IL-22 expression was found to be increased in patients with ulcerative colitis (UC). Whether genetic polymorphisms of IL-22 also influence UC risk is still unknown. The purpose of this study was to investigate the association between the IL-22 gene polymorphisms (-429 C/T, +1046 T/A and +1995 A/C) and the risk of UC in Chinese Han patients.

METHODS

This hospital-based case-control study comprised 180 patients with UC and 180 age- and gender-matched controls. Genotypes of 3 common polymorphisms of the IL-22 gene were determined by fluorogenic 5' exonuclease assays (TaqMan).

RESULTS

Patients with UC had a significantly higher frequency of IL-22 -429 TT genotype [odds ratio (OR) =2.43, 95% confidence interval (CI) =1.35, 4.37; P=0.003] and -429 T allele (OR =1.54, 95% CI=1.14, 2.07; P=0.004) than controls. The findings are still emphatic by the Bonferroni correction. The IL-22+1046 T/A and IL-22+1995 A/C gene polymorphisms were not associated with a risk of UC. When stratifying by clinical type, location and disease severity of UC, no significant differences were found in any groups.

CONCLUSION

This is the first study to provide evidence for an association of IL-22 -429 C/T gene polymorphisms with UC risk. Additional well-designed large studies were required for the validation of our results.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_183.

IL-22 produced by cancer-associated fibroblasts promotes gastric cancer cell invasion via STAT3 and ERK signaling

BACKGROUND

Interleukin-22 (IL-22) has been recently highlighted owing to its biological significance in the modulation of tissue responses during inflammation. However, the role of IL-22 in carcinogenesis has remained unclear. Here, we investigated the pathophysiological significance of IL-22 expression in gastric cancer tissues and examined the mechanism by which IL-22 promotes gastric cancer cell invasion.

METHODS

Human gastric cancer specimens were analysed by immunohistochemistry for expression of IL-22 and IL-22 receptor 1 (IL-22R1). The effects of IL-22-induced STAT3 and ERK signalling on invasive ability of gastric cancer cells were examined using a small-interfering RNA system and specific inhibitors. AGS cells were co-cultured with cancer-associated fibroblasts (CAFs) from human gastric cancer tissues and assessed by invasion assay.

RESULTS

Interleukin-22 and its receptor were expressed in α-smooth muscle actin-positive stromal cells and tumour cells at the invasive front of gastric cancer tissues, respectively. The expression of IL-22 and IL-22R1 was significantly related to lymphatic invasion. Interleukin-22 treatment promoted the invasive ability of gastric cancer cells through STAT3 and ERK activation. The invasive ability of gastric cancer cells was significantly enhanced by co-culture with IL-22-expressing CAFs.

CONCLUSIONS

Interleukin-22 produced by CAFs promotes gastric cancer cell invasion via STAT3 and ERK signalling.

Role of IL-22 in inflammatory bowel disease

Interleukin-22 (IL-22), a novel IL-10 associated factor, was originally discovered in 2000. It has been found that IL-22 is involved in the pathogenesis of a variety of inflammatory and autoimmune diseases. Although IL-22 and its receptor have not been linked with inflammatory bowel disease (IBD) genetically, expression of IL-22 is augmented in patients with IBD. Despite the fact that IL-22 is correlated with disease activities in IBD patients, data from several preclinical models suggest that IL-22 exerts protective functions. IBD susceptibility genes such as IL-23R, IL-17 and signal transducer and activator of transcription 3 (STAT3) are functionally associated with IL-22 directly or indirectly. These findings suggest that further studies on IL-22 would have the potential not only to analyze the fundamental mechanism of IBD but also to provide important rationale to develop novel therapeutic measures for this disorder.