Molecular mechanisms of lipotoxicity in nonalcoholic fatty liver disease

Semin Liver Dis. 2008 Nov;28(4):360-9. doi: 10.1055/s-0028-1091980. Epub 2008 Oct 27.


Nonalcoholic fatty liver disease (NAFLD) is characterized by insulin resistance, which results in elevated serum concentration of free fatty acids (FFAs). Circulating FFAs provide the substrate for triacylglycerol formation in the liver, and may also be directly cytotoxic. Hepatocyte apoptosis is a key histologic feature of NAFLD, and correlates with progressive inflammation and fibrosis. The molecular pathways leading to hepatocyte apoptosis are not fully defined; however, recent studies suggest that FFA-induced apoptosis contributes to the pathogenesis of nonalcoholic steatohepatitis. FFAs directly engage the core apoptotic machinery by activating the proapoptotic protein Bax, in a c-jun N-terminal kinase-dependent manner. FFAs also activate the lysosomal pathway of cell death and regulate death receptor gene expression. The role of ER stress and oxidative stress in the pathogenesis of nonalcoholic steatohepatitis has also been described. Understanding the molecular mediators of liver injury should promote development of mechanism-based therapeutic interventions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Apoptosis
  • Endoplasmic Reticulum / metabolism
  • Fatty Acids, Nonesterified / metabolism
  • Fatty Liver / metabolism*
  • Hepatocytes / pathology
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Liver / metabolism*
  • Mitochondria, Liver / metabolism
  • Toll-Like Receptors / metabolism
  • Tumor Necrosis Factor-alpha / metabolism


  • Fatty Acids, Nonesterified
  • Toll-Like Receptors
  • Tumor Necrosis Factor-alpha
  • JNK Mitogen-Activated Protein Kinases