Environmental factors such as diets rich in saturated fats contribute to dysfunction and death of pancreatic beta-cells in diabetes. Endoplasmic reticulum (ER) stress is elicited in beta-cells by saturated fatty acids. Here we show that palmitate-induced beta-cell apoptosis is mediated by the intrinsic mitochondrial pathway. By microarray analysis, we identified a palmitate-triggered ER stress gene expression signature and the induction of the BH3-only proteins death protein 5 (DP5) and p53-upregulated modulator of apoptosis (PUMA). Knockdown of either protein reduced cytochrome c release, caspase-3 activation, and apoptosis in rat and human beta-cells. DP5 induction depends on inositol-requiring enzyme 1 (IRE1)-dependent c-Jun NH(2)-terminal kinase and PKR-like ER kinase (PERK)-induced activating transcription factor (ATF3) binding to its promoter. PUMA expression is also PERK/ATF3-dependent, through tribbles 3 (TRB3)-regulated AKT inhibition and FoxO3a activation. DP5(-/-) mice are protected from high fat diet-induced loss of glucose tolerance and have twofold greater pancreatic beta-cell mass. This study elucidates the crosstalk between lipotoxic ER stress and the mitochondrial pathway of apoptosis that causes beta-cell death in diabetes.

Death Protein 5 and p53-Upregulated Modulator of Apoptosis Mediate the Endoplasmic Reticulum Stress-Mitochondrial Dialog Triggering Lipotoxic Rodent and Human beta-Cell Apoptosis.

MARSELLI, LORELLA;MARCHETTI, PIERO;
2012

Abstract

Environmental factors such as diets rich in saturated fats contribute to dysfunction and death of pancreatic beta-cells in diabetes. Endoplasmic reticulum (ER) stress is elicited in beta-cells by saturated fatty acids. Here we show that palmitate-induced beta-cell apoptosis is mediated by the intrinsic mitochondrial pathway. By microarray analysis, we identified a palmitate-triggered ER stress gene expression signature and the induction of the BH3-only proteins death protein 5 (DP5) and p53-upregulated modulator of apoptosis (PUMA). Knockdown of either protein reduced cytochrome c release, caspase-3 activation, and apoptosis in rat and human beta-cells. DP5 induction depends on inositol-requiring enzyme 1 (IRE1)-dependent c-Jun NH(2)-terminal kinase and PKR-like ER kinase (PERK)-induced activating transcription factor (ATF3) binding to its promoter. PUMA expression is also PERK/ATF3-dependent, through tribbles 3 (TRB3)-regulated AKT inhibition and FoxO3a activation. DP5(-/-) mice are protected from high fat diet-induced loss of glucose tolerance and have twofold greater pancreatic beta-cell mass. This study elucidates the crosstalk between lipotoxic ER stress and the mitochondrial pathway of apoptosis that causes beta-cell death in diabetes.
Cunha Daniel, A; Igoillo Esteve, M; Gurzov Esteban, N; Germano, C; Naamane, N; Marhfour, I; Fukaya, M; Vanderwinden J., M; Gysemans, C; Mathieu, Cl; Marselli, Lorella; Marchetti, Piero; Harding Heather, P; Ron, D; Eizirik D., L; Cnop, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/156840
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