Metformin ameliorates chronic colitis in a mouse model by regulating interferon‐γ‐producing lamina propria CD4+ T cells through AMPK activation. Issue 2 (22nd January 2022) - Takahara, Masahiro
Abstract: Metformin, a commonly prescribed drug for type 2 diabetes mellitus, has been shown to activate AMP‐activated protein kinase (AMPK). Notably, AMPK activation has recently been observed to be associated with anti‐inflammatory responses. Metformin is also reported to elicit anti‐inflammatory responses in CD4 + T cells, resulting in improvement in experimental chronic inflammatory diseases, such as systemic lupus erythematosus. To investigate the effect of metformin on inflammatory bowel disease (IBD), we developed a T cell‐transfer model of chronic colitis in which SCID mice were injected with CD4 + CD45RB high T cells to induce colitis. We examined the effects of metformin via in vitro and in vivo experiments on lamina propria (LP) CD4 + T cells. We observed that metformin suppresses the frequency of interferon (IFN) ‐γ‐producing LP CD4 + T cells in vitro, which were regulated by AMPK activation, a process possibly induced by the inhibition of oxidative phosphorylation. Furthermore, we examined the effects of metformin on an in vivo IBD model. Metformin‐treated mice showed AMPK activation in LP CD4 + T cells and ameliorated colitis. Our study demonstrates that metformin‐induced AMPK activation in mucosal CD4 + T cells contributes to the improvement of IBD by suppressing IFN‐γ production. Moreover, our results indicate that AMPK may be a target molecule for the regulation of mucosal immunity and inflammation. Thus, AMPK‐activating drugs such as metformin may be potential therapeutic agents for the treatment of IBD.