Inhibition of Calcium Influx Reduces Dysfunction and Apoptosis in Lipotoxic Pancreatic β-Cells via Regulation of Endoplasmic Reticulum Stress

PLoS One. 2015 Jul 6;10(7):e0132411. doi: 10.1371/journal.pone.0132411. eCollection 2015.

Abstract

Lipotoxicity plays an important role in pancreatic β-cell failure during the development of type 2 diabetes. Prolonged exposure of β-cells to elevated free fatty acids level could cause deterioration of β-cell function and induce cell apoptosis. Therefore, inhibition of fatty acids-induced β-cell dysfunction and apoptosis might provide benefit for the therapy of type 2 diabetes. The present study examined whether regulation of fatty acids-triggered calcium influx could protect pancreatic β-cells from lipotoxicity. Two small molecule compounds, L-type calcium channel blocker nifedipine and potassium channel activator diazoxide were used to inhibit palmitic acid-induced calcium influx. And whether the compounds could reduce palmitic acid-induced β-cell failure and the underlying mechanism were also investigated. It was found that both nifedipine and diazoxide protected MIN6 pancreatic β-cells and primary cultured murine islets from palmitic acid-induced apoptosis. Meanwhile, the impaired insulin secretion was also recovered to varying degrees by these two compounds. Our results verified that nifedipine and diazoxide could reduce palmitic acid-induced endoplasmic reticulum stress to generate protective effects on pancreatic β-cells. More importantly, it suggested that regulation of calcium influx by small molecule compounds might provide benefits for the prevention and therapy of type 2 diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Calcium Signaling / drug effects*
  • Cell Line, Tumor
  • Diabetes Mellitus, Type 2 / metabolism*
  • Diabetes Mellitus, Type 2 / pathology
  • Diazoxide / pharmacology
  • Endoplasmic Reticulum Stress / drug effects*
  • Insulin-Secreting Cells / metabolism*
  • Insulin-Secreting Cells / pathology
  • Mice
  • Nifedipine / pharmacology
  • Palmitic Acid / toxicity*

Substances

  • Palmitic Acid
  • Nifedipine
  • Diazoxide

Grants and funding

This work was supported by grant from Shanghai Natural Science Foundation (14ZR1447700), National Natural Science Foundation of China (81473262, 81072681), National Science and Technology Major Project “Key New Drug Creation and Manufacturing Program” (2012ZX09301001-001, 2013ZX09103001-001).