SUCNR1 and fibrosis: Succinate activation of GPR91 has been shown to be important for fibroblast activation and ECM formation in murine intestinal fibrosis and non-alcoholic steatohepatitis (NASH)-associated fibrosis, as well as in fibrotic lung tissue from idiopathic pulmonary fibrosis patients and bleomycin-induced mice (Macias-Ceja et al., 2019; Liu et al., 2020).