Novel insights into the global proteome responses of insulin-producing INS-1E cells to different degrees of endoplasmic reticulum stress

J Proteome Res. 2010 Oct 1;9(10):5142-52. doi: 10.1021/pr1004086.

Abstract

Exposure of insulin-secreting β-cells to inflammatory cytokines or high concentrations of free fatty acids, factors involved in the pathogenesis of type 1 and type 2 diabetes, leads to endoplasmic reticulum (ER) stress, β-cell dysfunction, and eventually apoptotic β-cell death. The aim of this study was to investigate the impact of ER stress on β-cells at the protein level to evaluate the contribution of post-transcriptional and post-translational changes in ER stress-induced β-cell damage. INS-1E cells were exposed in vitro to the ER-stress inducer cyclopiazonic acid (CPA) at two concentrations, and protein changes were evaluated using 2D-DIGE. CPA, 25 μM, led to massive apoptosis, accompanied by a near complete protein translation shut-down. CPA, 6.25 μM, led to adaptation of the β-cells to ER stress. Identification of the differentially expressed proteins in the two conditions led to the discovery of a clear pattern of defense pathways, with post-translational modifications playing a crucial role. Key alterations included inhibition of insulin translation and post-translational modifications in ER chaperones HYOU1 and HSPA5. Also, a central role for 14-3-3 proteins is suggested. In conclusion, INS-1E cells are highly sensitive to ER stress, leading to important post-transcriptional and post-translational modifications that may contribute to β-cell dysfunction and death.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Blotting, Western
  • Cell Line, Tumor
  • Electrophoresis, Gel, Two-Dimensional
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Gene Expression / drug effects
  • Indoles / pharmacology
  • Insulin-Secreting Cells / drug effects
  • Insulin-Secreting Cells / metabolism*
  • Insulinoma / metabolism
  • Insulinoma / pathology
  • Protein Binding / drug effects
  • Proteome / analysis*
  • Proteome / genetics
  • Proteomics / methods*
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Enzyme Inhibitors
  • Indoles
  • Proteome
  • cyclopiazonic acid