Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inf...Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inflammatory response and catalyzes the production of itaconate.Studies have reported that IRG1/itaconate has a significant antioxidant effect.This study aimed to investigate the effect and mechanism of IRG1/itaconate on dextran sulfate so-dium(DSS)-induced colitis in vivo and in vitro.In vivo experiments,we found IRG1/itaconate ex-erted protective effects against acute colitis by increasing mice weight,the length of colon,reducing disease activity index and colonic inflammation.Meanwhile,IRG1 deletion aggravated the macrophages/CD4+/CD8+T-cell accumulation,and increased the release of interleukin(IL)-1b,tumor necrosis factor-a(TNF-a),IL-6,the activation of nuclear factor-kB(NF-kB)/mitogen-activated protein kinase(MAPK)signaling pathway,and gasdermin D(GSDMD)mediated pyrop-tosis.Four-octyl itaconate(4-OI),a derivative of itaconate,attenuated these changes,therefore relieved DSS-induced colitis.In vitro experiment,we found 4-OI inhibited the reactive oxygen species production,thereby inhibiting the activation of MAPK/NF-kB signaling pathway in RAW264.7 and murine bone-marrow-derived macrophages.Simultaneously,we found 4-OI inhib-ited caspase1/GSDMD-mediated pyroptosis to reduce the release of cytokines.Finally,we found anti-TNF-a agent reduced the severity of DSS-induced colitis and inhibited gasdermin E(GSDME)-mediated pyroptosis in vivo.Meanwhile,our study revealed that 4-OI inhibited caspase3/GSDME-mediated pyroptosis induced by TNF-a in vitro.Taken together,IRG1/itaconate exerted a pro-tective role in DSS-induced colitis by inhibiting inflammatory response and GSDMD/GSDME-medi-ated pyroptosis,which could be a promising candidate for IBD therapy.展开更多
基金supported by the National Natural Science Foundation of China(No.81701883,82072736,82172171)。
文摘Inflammatory bowel disease(IBD)is a chronic relapsing gastrointestinal disorder,while the treatment effect is not satisfactory.Immune responsive gene 1(IRG1)is a highly ex-pressed gene in macrophage in response to inflammatory response and catalyzes the production of itaconate.Studies have reported that IRG1/itaconate has a significant antioxidant effect.This study aimed to investigate the effect and mechanism of IRG1/itaconate on dextran sulfate so-dium(DSS)-induced colitis in vivo and in vitro.In vivo experiments,we found IRG1/itaconate ex-erted protective effects against acute colitis by increasing mice weight,the length of colon,reducing disease activity index and colonic inflammation.Meanwhile,IRG1 deletion aggravated the macrophages/CD4+/CD8+T-cell accumulation,and increased the release of interleukin(IL)-1b,tumor necrosis factor-a(TNF-a),IL-6,the activation of nuclear factor-kB(NF-kB)/mitogen-activated protein kinase(MAPK)signaling pathway,and gasdermin D(GSDMD)mediated pyrop-tosis.Four-octyl itaconate(4-OI),a derivative of itaconate,attenuated these changes,therefore relieved DSS-induced colitis.In vitro experiment,we found 4-OI inhibited the reactive oxygen species production,thereby inhibiting the activation of MAPK/NF-kB signaling pathway in RAW264.7 and murine bone-marrow-derived macrophages.Simultaneously,we found 4-OI inhib-ited caspase1/GSDMD-mediated pyroptosis to reduce the release of cytokines.Finally,we found anti-TNF-a agent reduced the severity of DSS-induced colitis and inhibited gasdermin E(GSDME)-mediated pyroptosis in vivo.Meanwhile,our study revealed that 4-OI inhibited caspase3/GSDME-mediated pyroptosis induced by TNF-a in vitro.Taken together,IRG1/itaconate exerted a pro-tective role in DSS-induced colitis by inhibiting inflammatory response and GSDMD/GSDME-medi-ated pyroptosis,which could be a promising candidate for IBD therapy.
