All experiments were performed in compliance with the standards for animal use and care set by the University of Michigan’s Committee for the Use and Care of Animals. Animals were anesthetized with isoflurane inhalation and partial (70%) hepatectomy was performed as previously described (4). PSI-6206 In addition, animals treated with anti-IL-22 antibody also expressed less TGF-. In conclusion, these data suggest that IL-22 is usually involved in liver regeneration and this may be due to conversation with IL-6 and TGF- cascades. Keywords:hepatocyte proliferation, cytokines, interleukin-6, transforming growth factor- the liver is unique in thatit has the ability to regenerate after resection or injury despite the fact that hepatocytes normally do not actively divide (12). After partial hepatectomy, mature hepatocytes will replicate until the normal hepatic mass is usually restored. Many investigators have studied models of partial hepatectomy to identify cytokines that are involved in hepatocyte proliferation and liver regeneration. For example, tumor necrosis factor- (TNF-), interleukin-6 (IL-6), macrophage inflammatory protein-2, and stem cell factor have all been shown to be important factors for hepatocyte proliferation and/or hepatic regeneration (5,8,18,19,28). IL-6 is usually a well-studied cytokine with a significant role in hepatic regeneration after partial hepatectomy (8,28). Hepatocyte proliferation is initiated through the nuclear translocation of signal transducer and activator of transcription (stat)-3 as a result of increased IL-6 levels after partial hepatectomy (8). Interleukin-22 (IL-22) is usually a member of the interleukin-10 (IL-10) family of cytokines (25). It is produced by activated T cells and natural killer (NK) cells (22,25) and acts via a heterodimeric receptor complex consisting of IL-22 receptor- (IL-22R) PSI-6206 and IL-10 receptor- (IL-10R) (13). Because of the lack of IL-22R expression in both resting and activated immune cells, IL-22 does not influence these cells in vitro or in vivo (23). It appears that the IL-22 receptor complex is usually expressed on number of other nonimmune tissues, including liver, kidney, and digestive and respiratory system tissues (1,10,14,27). At least one role for IL-22 includes the induction of acute phase reactants and participation in the cascade of mediators involved in inflammation. Boniface and colleagues (4) have shown that IL-22 inhibits epidermal differentiation and induces proinflammatory gene expression and migration in human keratinocytes. IL-22 PSI-6206 also promotes antimicrobial defense (24). A recent study supports a potential therapeutic role for IL-22 as a protective factor in hepatocellular injury (17). In both hepatocytes and colon cancer cell lines, IL-22 can activate multiple signaling pathways, including the Janus kinase signal transducer and activator of transcription factor (stat-3) and mitogen-activated protein kinase pathways (14). Brand et al. (5) have exhibited that low doses of IL-22 significantly increase proliferation in HT-29 cells, a colon cancer cell line. In addition, another recent investigation illustrated that IL-22 can induce hepatocyte proliferation in vitro in a dose-dependent manner (6). This study did not investigate the cellular mechanisms involved in IL-22’s effects in the setting of partial hepatectomy and studied this effect in vitro only. Our present investigation expands on previous information regarding IL-22’s effects in hepatocyte proliferation in that it outlines the kinetics involved in IL-22-initiated hepatocyte proliferation in vivo, files that there is a correlation between IL-22 upregulation and a stat-3-mediated signal transduction pathway and suggests that IL-22 may play a contributing role in liver regeneration after 70% hepatectomy. == MATERIALS Rabbit Polyclonal to CSGLCAT AND METHODS == == == == Materials. == Recombinant IL-22 protein, anti-IL-22 antibody, Quantikine mouse IL-6 ELISA kit, and mouse HGF Duoset ELISA Development kit were all obtained from R&D Systems (Minneapolis, MN). Cell proliferation kit was obtained from Amersham Pharmacia Biotech. Anti-stat-1, anti-phospho-stat-1, anti-stat-3, anti-phospho-stat-3, anti-stat-5, and anti-phospho-stat-5 antibodies were obtained from Santa Cruz Biotechnology, (Santa Cruz, CA). Anti-ERK1/2, anti-phospho-ERK1/2, and pro-TGF- were bought from Cell Signaling (Beverly, MA). Anti-GAPDH monoclonal antibody was bought from Chemicon International, (Temecula, CA). == 70 % hepatectomy model. == Feminine C57/BL6 mice (68 wk old) had been bought from Jackson Mating Laboratories (Pub Harbor, Me personally) and taken care of under particular pathogen-free conditions with free of charge usage of water and food before every test. All experiments had been performed in conformity with the specifications for animal make use of and care arranged by the College or university of Michigan’s Committee for the utilization and Treatment of Animals. Pets had been anesthetized with isoflurane inhalation and incomplete (70%) hepatectomy was performed as previously referred to (4). After PSI-6206 midline incision was performed, the median and remaining lateral lobes from the liver organ had been resected after a 3-0 silk suture ligature was guaranteed around the bottom of every lobe. Control pets underwent sham laparotomy without manipulation or resection from the liver organ. For the tests concerning administration of exogenous.
