Fenofibrate, but not ezetimibe, prevents fatty liver disease in mice lacking phosphatidylethanolamine N-methyltransferase

Abstract

Mice lacking phosphatidylethanolamine N-methyltransferase (PEMT) are protected from high-fat diet (HFD)-induced obesity and insulin resistance. However, these mice develop severe nonalcoholic fatty liver disease (NAFLD) when fed the HFD, which is mainly due to inadequate secretion of VLDL particles. Our aim was to prevent NAFLD development in mice lacking PEMT. We treated Pemt−/− mice with either ezetimibe or fenofibrate to see if either could ameliorate liver disease in these mice. Ezetimibe treatment did not reduce fat accumulation in Pemt−/− livers, nor did it reduce markers for hepatic inflammation or fibrosis. Fenofibrate, conversely, completely prevented the development of NAFLD in Pemt−/− mice: hepatic lipid levels, as well as markers of endoplasmic reticulum stress, inflammation, and fibrosis, in fenofibrate-treated Pemt−/− mice were similar to those in Pemt+/+ mice. Importantly, Pemt−/− mice were still protected against HFD-induced obesity and insulin resistance. Moreover, fenofibrate partially reversed hepatic steatosis and fibrosis in Pemt−/− mice when treatment was initiated after NAFLD had already been established. Increasing hepatic fatty acid oxidation can compensate for the lower VLDL-triacylglycerol secretion rate and prevent/reverse fatty liver disease in mice lacking PEMT.