Hepatocyte growth factor protects rat RINm5F cell line against free fatty acid-induced apoptosis by counteracting oxidative stress.
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.
Santangelo
Carmela
C
National Centre for Food Quality and Risk Assessment, Section of Nutrition, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. c.santan@iss.it
Matarrese
Paola
P
Masella
Roberta
R
Di Carlo
Maria Chiara
MC
Di Lillo
Angela
A
Scazzocchio
Beatrice
B
Vecci
Elio
E
Malorni
Walter
W
Perfetti
Riccardo
R
Anastasi
Emanuela
E
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002460:Cell Line; D005230:Fatty Acids, Nonesterified / Q000037:antagonists & inhibitors* / Q000502:physiology; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats
D005230:Fatty Acids, Nonesterified; D017228:Hepatocyte Growth Factor