Effects of leucine supplementation on the development of steatosis and steatohepatitis induced by Pten deletion in hepatocytes

Abstract

Nonalcoholic fatty liver disease (NAFLD) is a group of diseases characterized by an excess of lipids in the liver, comprising from simple hepatic steatosis (NAFL) to an eventual progression to more serious diseases such as steatohepatitis (NASH) and hepatocellular carcinoma (HCC). The constitutive activation of PI3K-mTORC2-Akt-mTORC1 pathway induced by Pten deletion in hepatocytes promotes, by mechanisms that are not well understood, the sequential development of NAFL-NASH-HCC. In a pilot study, we found that mice with Pten deletion in hepatocytes had increased branched-chain amino acids (BCAA) serum levels, and leucine supplementation (1,5% in drinking water, %w/v) reduced liver mass and serum ALT content, a maker of liver injury. However, the involvement of BCAA in the development of NAFLD is unknown. Therefore, the present study aims to investigate the effects of different BCAA leucine dose supplementation on the development of NAFL and NASH progression in mice with Pten deletion in hepatocytes (L-Pten KO). For this, mice with or without Pten deletion in hepatocytes (L-Pten KO) will be fed with a normalized diet supplemented or not with additional doses of leucine for 8 weeks. We will evaluate body weight, food intake, glucose and insulin tolerance, serum content of short-chain fatty acids and BCAA, liver mass, hepatic lipid (de novo lipogenesis, triacylglycerol synthesis, lipolysis, and VLDL secretion), and glucose metabolism (gluconeogenesis and glycogen synthesis and degradation), mitochondrial morphology and function, inflammation (leukocyte infiltration, cytokines content and lipid mediators), intracellular insulin and mTORC1 signaling, oxidative stress, and fibrosis.(AU)