Modeling Steatosis and Lipid‐Mediated Cell Injury Using Induced Pluripotent Stem Cell‐Derived‐Hepatocytes

Abstract

Non‐alcoholic fatty liver disease (NAFLD) is characterized by steatosis with varying degrees of hepatocellular injury, fibrosis and cirrhosis. The iPSC‐derived hepatocytes (iHep) model is a novel system to study the molecular and cellular basis of fat‐mediated injury. The objective of this study is to investigate invitro steatosis and lipotoxicity of free fatty acids in iPSC‐derived hepatocytes. Methods: A three stage differentiation protocol was used for derivation of metabolically active hepatocytes. The iHeps were exposed to various doses of free fatty acids (FFA), palmitic acid (PA) and oleic acid (OA) for 24 hours. Cell viability, apoptosis, oxidative stress, lipid accumulation, glucose consumption and apoB release were studied. Results: The FFA treatment showed a dose‐dependent accumulation of fat in the cytoplasm of iHeps. Micro and macro‐vesicular patterns of lipid accumulation were detected. A significant increase in apoB release was observed in the FFA group. Interestingly, cells loaded with lipid had increased consumption of glucose. At higher concentrations (over PA 200um and OA400um), the lipid induced apoptosis by activation of caspase 7. The mitochondrial membrane potential was higher at 24 hrs in the treatment group compared to that of control indicating perturbation in mitochondrial respiration. In conclusion, iPSC‐hepatocytes can be used for modeling fatty liver disease.