TCF7L2 is a key determinant of nonalcoholic fatty liver induced by carbohydrate intake I

Nonalcoholic fatty liver disease (NAFLD) associated with type 2 diabetes (T2D) easily progresses toward severe forms of nonalcoholic steatohepatitis (NASH) and fibrosis, and the underlying mechanism is under active investigation. Here, we established the role of transcription factor 7-like 2 (TCF7L2), the most significant T2D susceptibility gene, in NAFLD development and progression. Hepatic TCF7L2 expression was decreased in liver biopsies of patients with NAFLD. Based on the major risk factors for NAFLD development, liver-specific TCF7L2 knockout mice were subjected to a high-fat diet providing fatty acids (FAs) and refeeding/high-carbohydrate diet stimulating de novo lipogenesis. Hepatic TCF7L2 deficiency significantly increased the lipid synthetic pathways and hepatic TG accumulation by preferentially metabolizing carbohydrates than FAs. Mechanistically, TCF7L2 regulated miRNAs targeting SREBF1c and enhanced proteasome-mediated MLXIPL (ChREBP) degradation. Our findings will deepen the pathophysiological mechanism of NAFLD associated with dietary carbohydrate and diabetes, and will provide a potential target for treatment of NAFLD. Overall design: Hepatic mRNA profiles of 12-week-old TCF7L2 wild type (TCF7L2 WT) and liver-specific TCF7L2 knockout (TCF7L2 LKO) mice refed a normal chow diet (NCD) for 24 h