Autophagy plays a protective role in endoplasmic reticulum stress-mediated pancreatic β cell death

A Bartolome, C Guillen, M Benito - Autophagy, 2012 - Taylor & Francis
Autophagy, 2012Taylor & Francis
There is a growing evidence of the role of autophagy in pancreatic β cell homeostasis.
During development of type 2 diabetes, β cells are required to supply the increased demand
of insulin. In such a stage, β cells have to address high ER stress conditions that could lead
to abnormal insulin secretion, and ultimately, β cell death and overt diabetes. In this study,
we used insulin secretion-deficient β cells derived from fetal mice. These cells present an
increased accumulation of polyubiquitinated protein aggregates and LC3B-positive puncta …
There is a growing evidence of the role of autophagy in pancreatic β cell homeostasis. During development of type 2 diabetes, β cells are required to supply the increased demand of insulin. In such a stage, β cells have to address high ER stress conditions that could lead to abnormal insulin secretion, and ultimately, β cell death and overt diabetes. In this study, we used insulin secretion-deficient β cells derived from fetal mice. These cells present an increased accumulation of polyubiquitinated protein aggregates and LC3B-positive puncta, when compared with insulinoma-derived β cell lines. We found that insulin secretion deficiency renders these cells hypersensitive to endoplasmic reticulum (ER) stress-mediated cell death. Chemical or shRNA-mediated inhibition of autophagy increased β cell death under ER stress. On the other hand, rapamycin treatment increased both autophagy and cell survival under ER stress. Insulin secretion-deficient β cells showed a marked reduction of the antiapoptotic protein BCL2, together with increased BAX expression and ERN1 hyperactivation upon ER stress induction. These results showed how insulin secretion deficiency in β cells may be contributing to ER stress-mediated cell death, and in this regard, we showed how the autophagic response plays a prosurvival role.
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