Interleukin-22 Treatment Research Articles

GPx2 Induction Is Mediated Through STAT Transcription Factors During Acute Colitis.

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

Combination therapy: New hope for alcoholic hepatitis?

Alcoholic hepatitis (AH) is a severe form of alcoholic liver disease with high mortality. The pathogenesis of AH is not fully understood, but it is generally believed that inflammation is a key factor leading to liver failure in AH. Steroids, which have broad immunosuppressive effects, have been used for the treatment of AH over the last forty years. Steroids elicit modest improvement in short-term survival rate in patients with severe AH, but also cause severe side effects. Several specific inflammatory targets (e.g., IL-1, LPS, and gut microbiota) are currently under investigation for the treatment of AH with the goal to obviate or reduce steroid administration. In addition to inflammation, impaired liver regeneration is another major cause of liver failure in AH, which deteriorates further after steroid treatment because inflammation plays a key role in promoting liver repair. Interleukin-22 (IL-22) is a promising drug for the treatment of AH because of its hepatoprotective and anti-fibrotic functions and relatively few known side effects. In addition, IL-22 treatment also ameliorates bacterial infection and kidney injury, two major complications associated with severe AH. IL-22 is currently under investigation in preclinical and clinical studies and may hold great promise for AH by providing more beneficial effects and fewer side effects than current therapies.

IL22/IL-22R pathway induces cell survival in human glioblastoma cells.

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family that binds to a heterodimeric receptor consisting of IL-22 receptor 1 (IL-22R1) and IL-10R2. IL-22R expression was initially characterized on epithelial cells, and plays an essential role in a number of inflammatory diseases. Recently, a functional receptor was detected on cancer cells such as hepatocarcinoma and lung carcinoma, but its presence was not reported in glioblastoma (GBM). Two GBM cell lines and 10 primary cell lines established from patients undergoing surgery for malignant GBM were used to investigate the expression of IL-22 and IL-22R by using quantitative RT-PCR, western blotting and confocal microscopy studies. The role of IL-22 in proliferation and survival of GBM cell lines was investigated in vitro by BrdU and ELISA cell death assays. We report herein that the two subunits of the IL-22R complex are expressed on human GBM cells. Their activation, depending on exogenous IL-22, induced antiapoptotic effect and cell proliferation. IL-22 treatment of GBM cells resulted in increased levels of phosphorylated Akt, STAT3 signaling protein and its downstream antiapoptotic protein Bcl-xL and decreased level of phosphorylated ERK1/2. In addition, IL-22R subunits were expressed in all the 10 tested primary cell lines established from GBM tumors. Our results showed that IL-22R is expressed on GBM established and primary cell lines. Depending on STAT3, ERK1/2 and PI3K/Akt pathways, IL-22 induced GBM cell survival. These data are consistent with a potential role of IL-22R in tumorigenesis of GBM. Since endogenous IL-22 was not detected in all studied GBM cells, we hypothesize that IL-22R could be activated by immune microenvironmental IL-22 producing cells.

Therapy with interleukin-22 alleviates hepatic injury and hemostasis dysregulation in rat model of acute liver failure.

The therapeutic efficacy of interleukin-22 (IL-22) on liver injury and hematological disturbances was studied in rat model of acute liver failure (ALF) induced by D-galactosamine/lipopolysaccharide (D-GalN/LPS). The following parameters were investigated: (1) survival rate, (2) serum levels of liver function enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP)), total bilirubin (TBILI), and total albumen (ALB), (3) blood clotting tests (prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen level (FIB)) and white blood cells (WBCs), red blood cells (RBCs), and platelet counts, (4) hepatic levels of tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2), and (5) liver histopathology. After 48 hours of D-GalN/LPS, the rats exhibited 20% mortality, significant increases in AST, ALT, ALP, TBILI, PT, and aPTT, TNF-α, and COX-2 and significant decreases in FIB, WBCs, and RBCs. By contrast, therapy with IL-22 prevented the lethal effect of D-GalN/LPS by 100% and efficiently alleviated all the biochemical and hematological abnormalities that were observed in ALF untreated group. Furthermore, IL-22 treatment decreased the hepatic contents of TNF-α and COX-2. The histopathological findings also supported the hepatoprotective effect of IL-22. Taken together, therapy with IL-22 can represent a promising therapeutic tool against liver injury and its associated hemostasis disturbances.

Hepatoprotective and anti‐fibrotic functions of interleukin‐22: Therapeutic potential for the treatment of alcoholic liver disease

Interleukin-22 (IL-22) plays a key role in promoting antimicrobial immunity and tissue repair at barrier surfaces by binding to the receptors IL-22R1, which is generally thought to be expressed exclusively in epithelial cells, and IL-10R2. Our laboratory previously demonstrated that IL-22 plays an important role in ameliorating liver injury in many rodent models by targeting hepatocytes that express high levels of IL-22R1 and IL-10R2. Recently, we have identified high expression levels of IL-22R1 and IL-10R2 in liver progenitor cells and hepatic stellate cells (HSCs). Overexpression of IL-22 in vivo or treatment with IL-22 in vitro promotes proliferation of liver progenitor cells via a signal transducer and activator of transcription 3 (STAT3)-dependent mechanism. IL-22 treatment also prevents HSC apoptosis in vitro and in vivo. Surprisingly, overexpression of IL-22, via either gene targeting or exogenous administration of adenovirus expressing IL-22, reduces liver fibrosis and accelerates the resolution of liver fibrosis during recovery. The anti-fibrotic effects of IL-22 are mediated via the activation of STAT3 in HSCs and subsequent induction of suppressor of cytokine signaling 3, which induces HSC senescence. Taken together, the hepatoprotective, mitogenic, and anti-fibrotic effects of IL-22 are beneficial in ameliorating alcoholic liver injury. Importantly, due to the restricted expression of IL-22R1, IL-22 therapy is expected to have few side effects, thus making IL-22 a potential candidate for treatment of alcoholic liver disease.

Role of IL-22 in tissue regeneration in autoimmunity (P5164)

Abstract The various cell types in our bodies are constantly regenerating but at a different rate. In autoimmune diseases cells once destroyed can regenerate. However, immune system once activated continues to target and destroy these cells. Thus, tissue regeneration remains a challenge in these diseases. Cytokines play a major role in immune regulation, inflammation, tissue injury and autoimmunity. We have shown that immunostimulation by mycobacterial adjuvants such as BCG vaccine as well as complete Freund’s adjuvant (CFA) can prevent the autoimmune process and can stimulate tissue regeneration. These adjuvants induce regulatory Th17 (Treg17) cells and stimulate expression of Regenerative (Reg) genes such as Reg1 and Reg2 in pancreatic islets. Th17 cells also produce Interleukin-22 (IL-22) that has been shown to stimulate This is probably mediated through STAT3/ERK signaling. Reg gene expression. Blocking of IL-22 prevented the expression of Reg genes in vivo. In this study we explored the cell types that express Reg genes following IL-22 treatment by using RT-PCR analysis and by histological staining. Our hypothesis is that the Reg gene expression drives the islet regeneration following tissue injury by autoimmunity in type 1 diabetes. These approaches offer alternatives to tissue transplantation in autoimmunity.

Application of Interleukin-22 Mediates Protection in Experimental Acetaminophen-Induced Acute Liver Injury

Acetaminophen (APAP, paracetamol)-induced hepatotoxicity, although treatable by timely application of N-acetylcysteine, can be fatal. Because it is among the common causes of acute liver failure in intensive care units and in light of its gradually increasing incidence, the need for novel therapeutic strategies aimed at severe intoxication is apparent. Recently, it has been shown that IL-22, a STAT3-activating cytokine, has the capability to mediate liver protection. Herein, the protective potential of IL-22 in murine APAP-induced hepatotoxicity was assessed. Intravenous administration of prophylactic IL-22 significantly reduced serum alanine aminotransferase levels and histopathologic damage in APAP-induced liver injury, a process that coincided with increased hepatocyte proliferation invivo. Concomitant gene expression analysis revealed hepatic induction of genes prototypically up-regulated by the IL-22/STAT3 axis, among others suppressor of cytokine signaling-3, lipocalin-2, and α1-antichymotrypsin. Notably, in a translational setting of therapeutic treatment 2 hours after APAP, IL-22 supported protection in the context of suboptimal N-acetylcysteine dosing. IL-22 likewise connected to augmented hepatocyte proliferation in this experimental setting. As detected by analysis of inflammatory cytokine production, systemically applied IL-22 did not display acute immunomodulation/stimulation in otherwise untreated or endotoxemic mice. Those latter observations clearly confirm acute tolerability of systemically applied IL-22. Observations presented altogether suggest that therapeutic IL-22 administration is a conceivable tissue-protective regimen aimed at hard-to-treat patients with severe APAP-induced hepatotoxicity.

INTERLEUKIN-22 MODULATES GUT EPITHELIAL AND IMMUNE BARRIER FUNCTIONS FOLLOWING ACUTE ALCOHOL EXPOSURE AND BURN INJURY

Interleukin-22 (IL-22) maintains gut epithelial integrity and expression of antimicrobial peptides Reg3β and Reg3γ. Our laboratory has shown that acute alcohol/ethanol (EtOH) exposure before burn injury results in increased gut permeability, intestinal T-cell suppression, and enhanced bacterial translocation. Herein, we determined the effect of combined EtOH intoxication and burn injury on intestinal levels of IL-22 as well as Reg3β and Reg3γ expression. We further examined whether in vivo restitution of IL-22 restores gut permeability, Reg3β and Reg3γ levels, and bacterial load (e.g., gut bacterial growth) within the intestine after EtOH and burn injury. Male mice, ∼25g, were gavaged with EtOH (2.9 mg/kg) before receiving a ∼12.5% total-body-surface-area, full-thickness burn. Mice were immediately treated with saline control or IL-22 (1 mg/kg) by i.p. injection. One day after injury, there was a significant decrease in intestinal IL-22, Reg3β, and Reg3γ expression along with an increase in intestinal permeability and gut bacterial load after EtOH combined with burn injury, as compared with sham injury. Treatment with IL-22 normalized Reg3β and Reg3γ expression and attenuated the increase in intestinal permeability after EtOH and burn injury. Qualitatively, IL-22 treatment reduced the bacterial load in nearly half of mice receiving EtOH combined with burn injury. Our data indicate that IL-22 maintains gut epithelial and immune barrier integrity after EtOH and burn injury; thus, the IL-22/antimicrobial peptide pathway may provide a therapeutic target for the treatment of patients who sustain burn injury under the influence of EtOH.

Interleukin-22 promotes liver progenitor cell proliferation in mice and patients with in viral hepatitis (44.16)

Abstract The proliferation of liver progenitor cells (LPCs), which have bipotential capabilities to differentiate into hepatocytes and biliary epithelial cells, is often observed in the inflammatory region of chronic liver diseases; however, how inflammation promotes LPC proliferation remains obscure. We examined the role of IL-22 on LPC proliferation on human viral hepatitis patients and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet feeding mice model. We found that interleukin-22 (IL-22), a survival factor for hepatocytes, is highly elevated and correlates with the grade of inflammation and LPC proliferation in patients with viral hepatitis. In a murine model of LPC proliferation induced by feeding DDC diet, overexpression of IL-22 in the liver via the generation of liver-specific IL-22 transgenic (IL-22TG) mice or injection of IL-22 adenovirus markedly increases LPC proliferation. STAT3, the major downstream signal of IL-22, is highly activated in the LPCs from DDC-fed IL-22TG mice. An additional deletion of hepatocyte-specific STAT3 in IL-22TG mice diminishes LPC proliferation. In vitro IL-22 treatment activates STAT3 and increases cell proliferation of isolated EpCAM+CD45-LPCs from DDC-fed mice and BMOL cells (a mouse LPC line), both of which are detected expression of IL-22R1. Conclusion: inflammatory cell-derived IL-22 promotes LPC proliferation via an STAT3-dependent manner, and IL-22 is a key link between inflammation and LPC proliferation in viral hepatitis.

High Fat Diet Induces Formation of Spontaneous Liposarcoma in Mouse Adipose Tissue with Overexpression of Interleukin 22

Interleukin 22 (IL-22) is a T-cell secreted cytokine that modulates inflammatory response in nonhematopoietic tissues such as epithelium and liver. The function of IL-22 in adipose tissue is currently unknown. We generated a transgenic mouse model with overexpression of IL-22 specifically in adipose tissue. The IL-22 transgenic mice had no apparent changes in obesity and insulin resistance after feeding with high fat diet (HFD). Unexpectedly, all the IL-22 transgenic mice fed with HFD for four months developed spontaneous tumors in epididymal adipose tissue. Histological analysis indicated that the tumors were well-differentiated liposarcomas with infiltration of inflammatory cells. IL-22 overexpression promotes production of inflammatory cytokines such as IL-1β and IL-10 and stimulates ERK phosphorylation in adipose tissue. Furthermore, IL-22 treatment in differentiated 3T3-L1 adipocytes could induce IL-1β and IL-10 expression, together with stimulation of ERK phosphorylation. Taken together, our study not only established a novel mouse model with spontaneous liposarcoma, but also revealed that IL-22 overexpression may collaborate with diet-induced obesity to impact on tumor development in mouse.

Hepatoprotective effects of IL-22 on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice

Interleukin-22 (IL-22), a member of the IL-10 cytokine family that is produced by activated Th22, Th1 and Th17 cells as well as natural killer cells, plays an important role in increase of innate immunity, protection from damage and enhancement of regeneration. Here, we examined the effects of IL-22 on acute liver failure model induced by d-galactosamine (GalN) and lipopolysaccharide (LPS). Administration of recombinant human IL-22 (rhIL-22) reduced the death rate markedly and prevented mice from severe hepatic injury, as evidenced by decreased serum alanine aminotransferase (ALT) and total bilirubin (T.Bil) activity as well as improved histological signs in liver. Furthermore, IL-22 treatment decreased the hepatic malondialdehyde (MDA) contents and increased the reduced glutathione levels. Serum tumor necrosis factor α (TNF-α) level and hepatic caspase-3 activity were significantly lower in mice administrated with IL-22. Moreover, IL-22 treatment significantly enhanced activation of STAT3 and up-regulated the expression of Bcl-xL, heme oxygenase-1 (HO-1) and redox factor-1 (Ref-1) in the liver injury induced by GalN/LPS. Collectively, these data indicate that IL-22 can provide critical protection against GalN/LPS-induced liver injury through anti-apoptotic, anti-oxidant and anti-inflammatory actions.

Interleukin-22 Protects against Acute Alcohol-Induced Hepatotoxicity in Mice

The protective effects of interleukin-22 (IL-22) on acute alcohol-induced liver injury were investigated. Mice were gavaged with 7 doses of alcohol (56% wt/vol, 15.2 mL/kg of body weight for each dose) over the 24 h, and IL-22 (0.5 mg/kg BW) was given to the mice by injection into the tail vein 1 h after alcohol administration. The results indicated that acute alcohol administration caused prominent hepatic microvesicular steatosis and an elevation of serum transaminase activities, induced a significant decrease in hepatic glutathione in conjunction with enhanced lipid peroxidation, and increased hepatocyte apoptosis as well as hepatic TNF-alpha production. IL-22 treatment attenuated these adverse changes induced by acute alcohol administration. The protective effects of IL-22 on alcohol-induced hepatotoxicity were due mainly to its anti-inflammatory, anti-oxidant, and anti-apoptotic features.

Interleukin-22 suppresses the growth of A498 renal cell carcinoma cells via regulation of STAT1 pathway.

BackgroundRenal cell carcinoma (RCC) is one of the most common kidney cancers and is highly resistant to chemotherapy. Accumulating evidence suggests that interleukin-22 (IL-22) may mediate host defense against varietal pathogens as a proinflammatory and anti-inflammatory cytokine. The purpose of this study is to assess the inhibitory effects of IL-22 on human RCC cell line A498 and to investigate the possible mechanisms underlying the anti-tumor effects of this cytokine.MethodologyA498 cells, a RCC cell line, were used to assess the inhibitory growth effects of IL-22 using the MTT assay and flow cytometric analysis in vitro. BALB/C nude mice bearing A498 cell xenografts were used to examine the antitumor efficacy of IL-22 in vivo. Western blotting assay was performed to detect the regulation of the intracellular signaling pathway of IL-22.Principal FindingsWe found that IL-22 suppressed the growth of A498 cells in a dose-dependent manner and inhibited the growth of A498 xenografts. We also observed that IL-22 produced a dose-dependent inhibitory effect on A498 cells that involved the induction of G2/M cell cycle arrest without cell apoptosis. Moreover, we showed that the phosphorylation of STAT1 was increased and the phosphorylation of ERK1/2 was attenuated in A498 cells exposed to IL-22. The growth inhibition of A498 cells was partially revised after IL-22 treatment as the expression of STAT1 was knocked down. And inflammatory cytokines, interferon-α and tumor necrosis factor-α (TNF-α) were barely involved in the suppression of A498 cell xenografts treated with IL-22.ConclusionsIL-22 dose-dependently suppresses RCC cell line A498 cells in vitro and induces growth inhibition of A498 cell-bearing mouse xenografts. These results suggest that the anti-RCC effects of IL-22 are at least partially mediated through regulation of STAT1 signaling pathways and G2/M cell cycle arrest, rather than by inducing apoptosis and inflammatory cytokines.

IL-22 inhibits ox-LDL-induced apoptosis and increases Bcl-2 expression in CRL-1730 cells

Objective To investigate the effect of interleukin-22(IL-22) on apoptosis of CRL-1730 cells(human umbilical vein endothelial cell line) induced by ox-LDL and the possible mechanism.Methods Expression of IL-22 receptor R1(IL-22R1) mRNA in CRL-1730 cells stimulated with ox-LDL(100 μg/ml) was detected by fluorescence quantitative RT-PCR.Flow cytometry was applied to examine the effect of exogenous IL-22(20 ng/ml) on the ox-LDL-induced apoptosis of CRL-1730 cells.The expression of Bcl-2,Bcl-xl,Bcl-w,caspase 3,and STAT3 mRNA in CRL-1730 cells treated or untreated with IL-22 and ox-LDL were measured by fluorescence quantitative RT-PCR;the phosphorylation status of STAT3 and the Bcl-2 protein level were examined by Western blotting analysis.Results The expression of IL-22R1 mRNA increased in a time-dependent manner(P0.05) and peaked at 12 h after ox-LDL stimulation.Treatment with IL-22 significantly inhibited the apoptosis of CRL-1730 cells induced by ox-LDL(P0.01),increased the expression of anti-apoptosis genes Bcl-2,Bcl-xl,and Bcl-w,and decreased expression of caspase 3 mRNA(P0.01).STAT3 phosphorylation occurred 1-2 h after IL-22 treatment and Bcl-2 protein expression increased 4 h after IL-22 treatment in ox-LDL stimulated CRL-1730 cells.Conclusion IL-22 can inhibit the pro-apoptosis effect of ox-LDL in the CRL-1730 cells,which might be associated with the increased expression of Bcl-2,Bcl-xl,and Bcl-w mRNA,decreased expression of caspase 3,and induced STAT3 phosphorylation.

Interleukin-22 Treatment Ameliorates Alcoholic Liver Injury in a Murine Model of Chronic-Binge Ethanol Feeding: Role of Signal Transducer and Activator of Transcription 3

Interleukin-22 (IL-22), a recently identified member of the IL-10 family of cytokines that is produced by Th17 and natural killer cells, plays an important role in controlling bacterial infection, homeostasis, and tissue repair. Here, we tested the effect of IL-22 on alcohol-induced liver injury in a murine model of chronic-binge ethanol feeding. Feeding male C57BL/6 mice with a Lieber-DeCarli diet containing 5% ethanol for 10 days, followed by a single dose of ethanol (5 g/kg body weight) by gavage, induces significant fatty liver and liver injury with peak serum levels of approximately 250 IU/L alanine aminotransferase and 420 IU/L aspartate aminotransferase 9 hours after gavage. Moreover, chronic-binge ethanol administration increases expression of hepatic and serum inflammatory cytokines and hepatic oxidative stress. Using this model, we demonstrate that treatment with IL-22 recombinant protein activates hepatic signal transducer and activator of transcription 3 (STAT3) and ameliorates alcoholic fatty liver, liver injury, and hepatic oxidative stress. Administration with IL-22 adenovirus also prevents alcohol-induced steatosis and liver injury. Deletion of STAT3 in hepatocytes abolishes the hepatoprotection provided by IL-22 in alcoholic liver injury. In addition, IL-22 treatment down-regulates the hepatic expression of fatty acid transport protein, but up-regulates several antioxidant, antiapoptotic, and antimicrobial genes. Finally, expression of IL-22 receptor 1 is up-regulated whereas IL-22 is undetectable in the livers from mice with chronic-binge ethanol feeding or patients with alcoholic hepatitis. Chronic-binge ethanol feeding may be a useful model to study the early stages of alcoholic liver injury. IL-22 treatment could be a potential therapeutic option to ameliorate alcoholic liver disease, due to its antioxidant, antiapoptotic, antisteatotic, proliferative, and antimicrobial effects with the added benefit of potentially few side effects.