Non-canonical IL-22 receptor signaling remodels the mucosal barrier during fungal immunosurveillance.

Mucosal barrier integrity is vital for homeostasis with commensal organisms while preventing pathogen invasion. We unexpectedly found that fungal-induced immunosurveillance enhances resistance to fungal outgrowth and tissue invasion by remodeling the oral mucosal epithelial barrier in mouse models of adult and neonatal Candida albicans colonization. Epithelial subset expansion and tissue remodeling were dependent on interleukin-22 (IL-22) and signal transducer and activator of transcription 3 (STAT3) signaling, through a non-canonical receptor complex composed of glycoprotein 130 (gp130) coupled with IL-22RA1 and IL-10RB. Immunosurveillance-induced epithelial remodeling was restricted to the oral mucosa, whereas barrier architecture was reset once fungal-specific immunity developed. Collectively, these findings identify fungal-induced transient mucosal remodeling as a critical determinant of resistance to mucosal fungal infection during early stages of microbial colonization.

IL-22/IL-22RA1 Promotes Human Tenon's Capsule Fibroblasts Proliferation and Regulates Fibrosis Through STAT3 Signaling Pathway.

Purpose: Although it is now understood that most antiglaucoma surgeries fail because of scarring of the filtering tract, the underlying mechanism remains to be elucidated. The present study investigated the mechanism by which the interleukin (IL)-22/IL-22 receptor alpha 1 (IL-22RA1) signaling pathway regulates scar formation in glaucoma patients. Method: A total of 31 glaucoma patients who underwent trabeculectomy surgery with uncontrollable intraocular pressure because of scarring and 19 strabismus patients as the control patient group were included in the present study. ELISA was performed to measure the content of IL-22 in peripheral blood. Serum from patients was used to incubate human Tenon's capsule fibroblasts (HTFs) cells and IL-22 antibody rescued the effect of IL-22 on the biological functions. qPCR and Western blot were performed to determine IL-22RA1 mRNA and protein expression levels. Flow cytometry was performed to assess the cell cycle distribution and the Cell Counting Kit-8 assay was used to analyze cell proliferation. Results: The ELISA assay revealed that the serum IL-22 level of glaucoma patients was significantly higher than the healthy group (29.80 ± 5.1 ng/µL vs. 5.21 ± 0.9 ng/µL). After incubation with patient serum, the proliferation and activation of human Tenon fibroblasts (HTFs) were promoted. IL-22 mediated the biological function of HTFs via directly binding IL-22RA1. Moreover, transfection of the siR-IL-22RA1 or IL-22RA1 gene resulted in significant antifibrosis or profibrosis in HTFs. When a signal transducer and activator of transcription (STAT) 3 inhibitor (BAY) was introduced to the IL-22RA1 overexpression group, IL-22-induced proliferation was reduced in HTFs. Additionally, glaucoma patients had increased levels of IL-22 expression following surgery. Conclusions: The IL-22/IL-22RA1/STAT3 signaling pathway promoted fibroblast cell proliferation and alpha-smooth muscle actin, potentially regulating fibrosis in glaucoma filtration tracts. Our results provide hitherto undocumented insights into the pathophysiology of postoperative scarring.

IL-22 promotes mucin-type O-glycosylation and MATH1+ cell-mediated amelioration of intestinal inflammation.

The interleukin (IL)-22 cytokine can be protective or inflammatory in the intestine. It is unclear if IL-22 receptor (IL-22Ra1)-mediated protection involves a specific type of intestinal epithelial cell (IEC). By using a range of IEC type-specific Il22Ra1 conditional knockout mice and a dextran sulfate sodium (DSS) colitis model, we demonstrate that IL-22Ra1 signaling in MATH1+ cells (goblet and progenitor cells) is essential for maintaining the mucosal barrier and intestinal tissue regeneration. The IL-22Ra1 signaling in IECs promotes mucin core-2 O-glycan extension and induces beta-1,3-galactosyltransferase 5 (B3GALT5) expression in the colon. Adenovirus-mediated expression of B3galt5 is sufficient to rescue Il22Ra1IEC mice from DSS colitis. Additionally, we observe a reduction in the expression of B3GALT5 and the Tn antigen, which indicates defective mucin O-glycan, in the colon tissue of patients with ulcerative colitis. Lastly, IL-22Ra1 signaling in MATH1+ progenitor cells promotes organoid regeneration after DSS injury. Our findings suggest that IL-22-dependent protective responses involve O-glycan modification, proliferation, and differentiation in MATH1+ progenitor cells.

IL-22 promotes acute kidney injury through activation of the DNA damage response and cell death in proximal tubule cells.

Acute kidney injury (AKI) affects over 13 million people world-wide annually and is associated with a fourfold increase in mortality. Our lab and others have shown that DNA damage response (DDR) governs the outcome of AKI in a bimodal manner. Activation of DDR sensor kinases protects against AKI, while hyperactivation of DDR effector proteins, such as p53, induces to cell death and worsens AKI. The factors that trigger the switch from pro-reparative to pro-cell death DDR remain to be resolved. Here we investigate the role of interleukin 22 (IL-22), an IL-10 family member whose receptor (IL-22RA1) is expressed on proximal tubule cells (PTCs), in DDR activation and AKI. Using cisplatin and aristolochic acid (AA) induced nephropathy as models of DNA damage, we identify PTCs as a novel source of urinary IL-22, making PTCs the only epithelial cells known to secret IL-22, to our knowledge. Functionally, IL-22 binding its receptor (IL-22RA1) on PTCs amplifies the DDR. Treating primary PTCs with IL-22 alone induces rapid activation of the DDR in vitro. The combination of IL-22 + cisplatin or AA treatment on primary PTCs induces cell death, while the same dose of cisplatin or AA alone does not. Global deletion of IL-22 protects against cisplatin or AA induced AKI. IL-22 deletion reduces expression of components of the DDR and inhibits PTC cell death. To confirm PTC IL-22 signaling contributes to AKI, we knocked out IL-22RA1 in renal epithelial cells by crossing IL-22RA1floxed mice with Six2-Cre mice. IL-22RA1 KO reduced DDR activation, cell death, and kidney injury. These data demonstrate that IL-22 promotes DDR activation in PTCs, switching pro-recovery DDR responses to a pro-cell death response and worsening AKI. Targeting IL-22 represents a novel therapeutic approach to prevent the negative consequences of the DDR activation while not interfering with the processes necessary for repair of damaged DNA.

IL22RA1/JAK/STAT Signaling Acts As a Cancer Target Through Pan-Cancer Analysis.

Cytokines and cytokine receptors are important mediators in immunity and cancer development. Interleukin 22 (IL22) is one of the most important cytokines which has protumor effect. Given that common and specific roles of cytokines/receptors in multiple cancers, we conducted a pan-cancer study to investigate the role of IL22RA1 in cancer using The Cancer Genome Atlas (TCGA) database. Notably, we found IL22RA1 transcript was upregulated in 11 cancer types compared with their corresponding control. The mRNA expression level of IL22RA1 was highest in the pancreas among tumor tissues. The higher expression of IL22RA1 was associated with worse overall survival rate in patients. A total of 30 IL22RA1-correlated genes (e.g. IL17D, IL22RA2, IL20RB, IL10RA, IL10RB, TSLP and TYK2) are involved in the JAK/STAT pathway which promotes tumor progression. The upregulation of IL22RA1 in tumors was correlated with immune cell infiltration level. Higher expression of IL22RA2, IL20RB, IL10RA, IL10RB, TSLP, TYK2, STAT1 and STAT3 was associated with decreased overall survival rate in patients. IL22RA1 mutation was observed more in uterine cancer and melanoma compared with the other cancer types. Deactivation of IL22RA1 induced a lot of changes in gene expression. IL22RA1 mutants had upregulated DNA damage/repair genes in uterine cancer, whereas downregulated genes in the FoxO signaling pathway. In melanoma, mutation of IL22RA1 can upregulate the HIF signaling pathway but downregulate metabolic pathways. Our study suggests that IL22RA1/JAK/STAT signaling can be an important target for cancer treatment.

High IL-22RA1 gene expression is associated with poor outcome in muscle invasive bladder cancer.

BACKGROUND: The cell surface interleukin 22 (IL-22) receptor complex is mainly expressed in epithelial and tissue cells like pancreatitis cells. Recent studies described that IL-22R was overexpressed in malignant diseases and was associated with a poor overall survival (OS). The role of IL-22RA1 gene expression in muscle invasive bladder cancer (MIBC) has not been investigated, yet. OBJECTIVES: The aim of this study was to analyze the role of IL-22RA1 gene expression in patients with MIBC. METHODS: In a cohort of 114 patients with MIBC who underwent radical cystectomy, IL-22RA1 gene expression was analyzed with qRT-PCR and correlated with clinical parameters. Furthermore, Kaplan-Meier and Cox regression analysis were performed. For validation, an in silico dataset (TCGA 2017, n=407) was reanalyzed. RESULTS: IL-22RA1 gene expression was independent of clinicopathological parameters like age (P=0.2681), T stage (P=0.2130), nodal status (P=0.3238) and lymph vascular invasion (LVI, P=0.5860) in patients with MIBC. A high expression of IL-22RA1 was associated with a shorter OS (P=0.0040) and disease-specific survival (P=0.0385). Furthermore, a shorter disease-free survival (DFS) was also associated with a high expression of IL-22RA1 (P=0.0102). In the multivariable analysis, IL-22RA1 expression was an independent prognostic predictors regarding OS (P=0.0096, HR=0.48). In the TCGA cohort, IL-22RA1 expression was independent regarding to OS and DFS. CONCLUSION: A high IL-22RA1 gene expression was associated with worse outcome. Furthermore, IL-22RA1 represented an independent predictor regarding OS in our cohort and therefore might be used for risk stratification in patients with MIBC.

Specific bioactivity of IL-22 in intestinal cells as revealed by the expression of IL-22RA1 in Mandarin fish, Siniperca chuatsi.

IL-22, a multifunctional cytokine, acts as an important regulator in host immunity in mammals. IL-22 homologues have been characterized in several species of fish, with its expression found in multiple tissues/cells in fish, but its target cells have not been fully analyzed. In the present research, different organ/tissue isolated cells were examined for the expression of IL-22 and the induced IL-22 responses in mandarin fish. The mandarin fish IL-22 was found to be expressed in all these tested cells with high basal expression in intestinal cells. The HKLs showed low basal expression but significant increase in expression of IL-22 after LPS treatment or bacterial infection. Only intestinal cells showed response to IL-22 by enhanced expression of hepcidin, LEAP2 and IL-22BP, with unresponsiveness observed in other tested cells, which indicated the cell-specificity of IL-22 bioactivity in mandarin fish. One of the heterodimeric receptor components for IL-22, the IL-22RA1, was cloned in mandarin fish, with four tandem fibronectin type III (FNIII) domains identified in its extracellular part. IL-22RA1 exhibited an intestinal cell-specific expression pattern, although another receptor component of IL-22, IL-10R2, displayed constitutive expressions in all these tested cells. The present study reveals that the mandarin fish IL-22 exhibits its bioactivity in a cell-specific manner in intestinal cells, which is reflected in the restrictive expression of its receptor unit, IL-22RA1.

IL-22Ra1 is induced during influenza infection by direct and indirect TLR3 induction of STAT1.

BACKGROUND: Influenza attacks the epithelium of the lung, causing cell death and disruption of the epithelial barrier leading to fluid buildup in the lung and impairment of gas exchange. Limited treatment options for severe influenza pneumonia prioritize the need for the discovery of effective therapies. IL-22 is a cytokine that promotes tissue integrity and has strong promise as a treatment option. While research has been focused on the cytokine itself, there is limited understanding of the regulation of the IL-22 receptor (IL-22Ra1) at the epithelial surface during infection. METHODS: IL-22Ra1 levels were measured by qRT-PCR, western blot and immunofluorescence following H1N1 influenza infection (A/PR/8/34 H1N1) or synthetic TLR3 mimetic, Poly (I:C). Regulation of the receptor was determined using STAT inhibitors (STAT1, STAT3 and PanSTAT inhibitors), TLR3 inhibition, and neutralization of interferon alpha receptor 2 (IFNAR2). Significance was determined by a p-value of greater than 0.05. Significance between two groups was measured using unpaired t-test and significance between more than two groups was measured using one-way ANOVA with Tukey Multiple Comparison Test. RESULTS: Here we show both in vivo and in vitro that IL-22Ra1 was induced as early as 24 h after influenza (H1N1 PR8) infection. This induction was triggered by toll-like receptor 3 (TLR3) as a TLR3 mimetic [Poly (I:C)] also induced IL-22Ra1 and inhibition of endosomal formation required for TLR3 function inhibited this process. This upregulation was dependent upon IFNß signaling through STAT1. Importantly, induction of IL-22Ra1 significantly increased IL-22 signaling as evidenced by pSTAT3 levels following IL-22 treatment. CONCLUSION: Collectively, these data suggest epithelial cells may optimize the beneficial effects of IL-22 through the induction of the IL-22 receptor during viral infection in the lung.

IL22 Inhibits Epithelial Stem Cell Expansion in an Ileal Organoid Model.

Background & Aims: Crohn's disease is an inflammatory bowel disease that affects the ileum and is associated with increased cytokines. Although interleukin (IL)6, IL17, IL21, and IL22 are increased in Crohn's disease and are associated with disrupted epithelial regeneration, little is known about their effects on the intestinal stem cells (ISCs) that mediate tissue repair. We hypothesized that ILs may target ISCs and reduce ISC-driven epithelial renewal. Methods: A screen of IL6, IL17, IL21, or IL22 was performed on ileal mouse organoids. Computational modeling was used to predict microenvironment cytokine concentrations. Organoid size, survival, proliferation, and differentiation were characterized by morphometrics, quantitative reverse-transcription polymerase chain reaction, and immunostaining on whole organoids or isolated ISCs. ISC function was assayed using serial passaging to single cells followed by organoid quantification. Single-cell RNA sequencing was used to assess Il22ra1 expression patterns in ISCs and transit-amplifying (TA) progenitors. An IL22-transgenic mouse was used to confirm the impact of increased IL22 on proliferative cells in vivo. Results: High IL22 levels caused decreased ileal organoid survival, however, resistant organoids grew larger and showed increased proliferation over controls. Il22ra1 was expressed on only a subset of ISCs and TA progenitors. IL22-treated ISCs did not show appreciable differentiation defects, but ISC biomarker expression and self-renewal-associated pathway activity was reduced and accompanied by an inhibition of ISC expansion. In vivo, chronically increased IL22 levels, similar to predicted microenvironment levels, showed increases in proliferative cells in the TA zone with no increase in ISCs. Conclusions: Increased IL22 limits ISC expansion in favor of increased TA progenitor cell expansion.

Molecular characterization and expression analysis of IL-22 and its two receptors genes in yellow catfish (Pelteobagrus filvidraco) in response to Edwardsiella ictaluri challenge.

Interleukin (IL)-22, as a member of the interleukin (IL)-10 family, is an important mediator between the immune cells and epithelial tissues during infection and inflammation. This study reported the characterization and mRNA expression patterns of Pf_IL-22 gene and its cell surface-associated receptors Pf_IL-22RA1 and soluble Pf_IL-22RA2 genes in yellow catfish (Pelteobagrus filvidraco). The open reading frames (ORFs) of the Pf_IL-22, Pf_IL-22RA1 and Pf_IL-22RA2 genes were 546 bp, 1740 bp and 690 bp in length, encoding 181, 579 and 229 amino acids, respectively. Alignments of the deduced amino acid sequences present that the Pf_IL-22 has a conserved IL-10 family signature motif, and the Pf_IL-22RA1 and Pf_IL-22RA2 have two conserved fibronectin type-III domains. Quantitative real-time PCR (qPCR) analyses showed that the Pf_IL-22 and Pf_IL-22RA1 mRNAs were highly expressed in mucosal tissues such as the fin, gill, intestine, skin mucus and stomach, and were weakly expressed in the kidney, liver and head kidney of adult yellow catfish, indicating that the Pf_IL-22 transcripts may be mainly produced by mucosal immune cells/tissues in healthy yellow catfish. The mRNA expression levels of the Pf_IL-22RA2 gene were high in the muscle and liver, and were relatively low in the spleen and kidney. The mRNA expression levels of the Pf_IL-22 and its two receptor genes were significantly up-regulated in both mucosal tissues (gill, hindgut, and skin mucus) and systemic immune tissues (spleen, head kidney and blood) after Edwardsiella ictaluri challenge. These results indicated that the Pf_IL-22 and its two receptors genes might play an important role in the innate immune defense against bacterial invasion.

Impact of IL-22 and IL-22 receptor alpha 1 polymorphisms on preeclampsia risk in Chinese Han women.

Previous studies have indicated that an increased inflammatory response plays an important role in preeclampsia (PE), and rising levels of interleukin (IL)-22 can trigger inflammation and hyperproliferation, leading to increased production of several pro-inflammatory cytokines such as IL-1, IL-6, and IL-8. We aimed to investigate the association between polymorphisms of IL-22 and IL-22 receptor alpha 1 gene (IL-22RA1) and PE in Chinese Han population. Single nucleotide polymorphisms (SNPs) rs2227485 in IL-22 and rs3795299 in IL-22RA were genotyped by Taqman real-time PCR in 1071 PE patients and 1263 control subjects. Differences in genetic distribution were compared between two groups using the chi-square test. Significant differences were observed in genotypic and allelic frequencies of IL-22RA1 rs3795299 between healthy controls and PE patients (P < 0.001 by genotype; P = 0.001, odds ratio = 1.253, 95% confidence interval 1.103-1.424 by allele). There were also significant differences in genotypic and allelic frequencies of rs3795299 between late-onset/mild PE and control groups. In addition, we found obvious statistic difference for the allele of early-onset PE/the genotype of late-onset PE and control subgroups for IL-22 rs2227485. IL-22 rs2227485 and IL-22RA1 rs3795299 may be associated with the development of PE in Chinese Han population. However, further validation is required in other populations, as well as an evaluation of the association of other SNPs in IL-22 and IL-22RA1 with PE.

Th22 cells increase in poor prognosis multiple myeloma and promote tumor cell growth and survival.

There is increased production of plasmacytoid dendritic cells (pDCs) in the bone marrow (BM) of multiple myeloma (MM) patients and these favor Th22 cell differentiation. Here, we found that the frequency of interleukin (IL)-22+IL-17-IL-13+ T cells is significantly increased in peripheral blood (PB) and BM of stage III and relapsed/refractory MM patients compared with healthy donors and patients with asymptomatic or stage I/II disease. Th22 cells cloned from the BM of MM patients were CCR6+CXCR4+CCR4+CCR10- and produced IL-22 and IL-13 but not IL-17. Furthermore, polyfunctional Th22-Th2 and Th22-Th1 clones were identified based on the co-expression of additional chemokine receptors and cytokines (CRTh2 or CXCR3 and IL-5 or interferon gamma [IFNγ], respectively). A fraction of MM cell lines and primary tumors aberrantly expressed the IL-22RA1 and IL-22 induced STAT-3 phosphorylation, cell growth, and resistance to drug-induced cell death in MM cells. IL-13 treatment of normal BM mesenchymal stromal cells (MSCs) induced STAT-6 phosphorylation, adhesion molecule upregulation, and increased IL-6 production and significantly favored MM cell growth compared with untreated BM MSCs. Collectively, our data show that increased frequency of IL-22+IL-17-IL-13+ T cells correlates with poor prognosis in MM through IL-22 and IL-13 protumor activity and suggest that interference with IL-22 and IL-13 signaling pathways could be exploited for therapeutic intervention.