Hepatocyte growth factor protects rat RINm5F cell line against free fatty acid-induced apoptosis by counteracting oxidative stress

J Mol Endocrinol. 2007 Feb;38(1-2):147-58. doi: 10.1677/jme.1.02133.

Abstract

Type 2 diabetes is characterized by peripheral insulin resistance, pancreatic beta-cells dysfunction, and decreased beta-cell mass with increased rate of apoptosis. Chronic exposure to high levels of free fatty acids (FFAs) has detrimental effects on beta-cell function and survival. FFAs have adverse effects on mitochondrial function, with a consequent increase in the production of reactive oxygen species. Hepatocyte growth factor (HGF) plays a critical role in promoting beta-cell survival. In the present study, we investigated whether HGF was capable of protecting beta-cells from death induced by prolonged exposure to FFAs. RINm5F cell line was cultured in the presence of FFAs (oleate:palmitate 2:1) for 72 h in order to induce apoptosis. Simultaneous administration of HGF and FFAs significantly suppressed the impaired insulin secretion and FFA-induced apoptosis. Specifically, HGF exerted its protective effect by counteracting: (i) the overproduction of either hydrogen peroxide and superoxide anion, (ii) the reduction of intracellular gamma-glutamylcysteinylglycine level, and (iii) the depolarization of mitochondrial membrane, induced by prolonged FFAs exposure. These effects appear to be mediated by bcl-2 and phosphatidylinositol 3 kinase (PI3K)/Akt pathways. Indeed, HGF increased mRNA and protein expression of bcl-2 downregulated by FFAs-treatment; moreover, pre-treatment with the specific PI3-kinase inhibitor LY294002, significantly abolished the protective effect of HGF. In conclusion, in rat insulin-producing RINm5F cells, HGF exerts its prosurvival effect by counteracting the increased intracellular oxidative stress and, consequently, by inhibiting apoptosis induced by chronic exposure to FFAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Cell Line
  • Fatty Acids, Nonesterified / antagonists & inhibitors*
  • Fatty Acids, Nonesterified / physiology
  • Hepatocyte Growth Factor / physiology*
  • Insulin-Secreting Cells / metabolism
  • Oxidative Stress / physiology*
  • Rats

Substances

  • Fatty Acids, Nonesterified
  • Hepatocyte Growth Factor