IGF2/IGF2R/Sting signaling as a therapeutic target in DSS-induced ulcerative colitis

Abstract

Ulcerative colitis is an inflammatory bowel disease with increasing prevalence and incidence. Current treatments for ulcerative colitis are not generally applicative and are often accompanied by side effects. IGF2 is an endogenous protein that plays roles in anti-inflammation and stemness maintenance, but little is known about its mechanism and function in the progression of ulcerative colitis. In this study, mouse recombinant IGF2 was used in a mouse model of ulcerative colitis established by DSS. IGF2 expression was reduced in colon tissues but not plasma of DSS-induced colitis mice. IGF2R expression was also decreased in colitis colons, which was then elevated by recombinant IGF2. Recombinant IGF2 alleviated colon injury in colitis, which was evaluated by colon shortening, body weight loss and DAI score. IGF2 treatment also relieved the inflammatory response in colitis, which was assessed by the spleen weight index, MPO activity and proinflammatory cytokine expression and was also detected in LPS-stimulated RAW264.7 cells in vitro. Moreover, IGF2R was predicted and further verified to interact with the Sting protein, and the cGAS-Sting pathway as a key pathway for stemness regulation, was upregulated in colonic colons, which was blocked by IGF2 treatment. Additionally, IGF2 treatment can maintain colonic stemness and further repair colonic tight junction function in DSS-induced colitis. In conclusion, IGF2/IGF2R downregulated the cGAS-Sting pathway to sustain colonic stemness and barrier integrity to protect against ulcerative colitis induced by DSS.