Hypoxia-inducible factor 2? drives hepatosteatosis through the fatty acid translocase CD36.

ABSTRACT: BACKGROUND & AIMS:Molecular mechanisms by which hypoxia might contribute to hepatosteatosis, the earliest stage in non-alcoholic fatty liver disease (NAFLD) pathogenesis, remain still to be elucidated. We aimed to assess the impact of hypoxia-inducible factor 2? (HIF2?) on the fatty acid translocase CD36 expression and function in vivo and in vitro. METHODS:CD36 expression and intracellular lipid content were determined in hypoxic hepatocytes, and in hypoxic CD36- or HIF2? -silenced human liver cells. Histological analysis, and HIF2? and CD36 expression were evaluated in livers from animals in which von Hippel-Lindau (Vhl) gene is inactivated (Vhlf/f -deficient mice), or both Vhl and Hif2a are simultaneously inactivated (Vhlf/f Hif2?/f -deficient mice), and from 33 biopsy-proven NAFLD patients and 18 subjects with histologically normal liver. RESULTS:In hypoxic hepatocytes, CD36 expression and intracellular lipid content were augmented. Noteworthy, CD36 knockdown significantly reduced lipid accumulation, and HIF2A gene silencing markedly reverted both hypoxia-induced events in hypoxic liver cells. Moreover livers from Vhlf/f -deficient mice showed histologic characteristics of non-alcoholic steatohepatitis (NASH) and increased CD36 mRNA and protein amounts, whereas both significantly decreased and NASH features markedly ameliorated in Vhlf/f Hif2?f/f -deficient mice. In addition, both HIF2? and CD36 were significantly overexpressed within the liver of NAFLD patients and, interestingly, a significant positive correlation between hepatic transcript levels of CD36 and erythropoietin (EPO), a HIF2? -dependent gene target, was observed in NAFLD patients. CONCLUSIONS:This study provides evidence that HIF2? drives lipid accumulation in human hepatocytes by upregulating CD36 expression and function, and could contribute to hepatosteatosis setup.

SUBMITTER: Rey E 

PROVIDER: S-EPMC7539965 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature