Glucolipotoxicity in INS-1E cells is counteracted by carnitine palmitoyltransferase 1 over-expression

Biochem Biophys Res Commun. 2008 Oct 31;375(4):517-21. doi: 10.1016/j.bbrc.2008.08.013. Epub 2008 Aug 13.

Abstract

Effects of non-esterified fatty acids (FAs) are accentuated when applied together with elevated glucose through preferential use of glucose as fuel, which leads to decreased oxidation of FAs. We examined how over-expression of the mitochondrial FA transporter carnitine palmitoyltransferase 1 (CPT1) affects glucose-stimulated insulin secretion (GSIS), apoptosis and ER stress in INS-1E cells cultured in the presence of elevated levels of glucose and palmitate. INS-1E cells were infected with Tet-ON regulated adenovirus containing CPT1 and cultured for 48h in the presence of 0.5mM palmitate and 20mM glucose. Over-expressing CPT1 lowered basal insulin secretion in a dose-dependent manner thereby improving GSIS from INS-1E cells. Also, apoptosis was alleviated and ER-stress markers p-eIF2alpha and CHOP were decreased in cells over-expressing CPT1. We conclude that regulated over-expression of CPT1 is beneficial for glucolipotoxic beta-cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae
  • Animals
  • Apoptosis
  • Carnitine O-Palmitoyltransferase / biosynthesis*
  • Carnitine O-Palmitoyltransferase / genetics
  • Cell Line
  • Endoplasmic Reticulum / metabolism
  • Eukaryotic Initiation Factor-2 / metabolism
  • Fatty Acids, Nonesterified / metabolism*
  • Fatty Acids, Nonesterified / toxicity
  • Glucose / metabolism*
  • Glucose / toxicity
  • Insulin / metabolism*
  • Insulin Secretion
  • Insulin-Secreting Cells / drug effects
  • Insulin-Secreting Cells / metabolism*
  • Palmitates / metabolism*
  • Palmitates / pharmacology
  • Rats
  • Transcription Factor CHOP / metabolism

Substances

  • Eukaryotic Initiation Factor-2
  • Fatty Acids, Nonesterified
  • Insulin
  • Palmitates
  • Transcription Factor CHOP
  • Carnitine O-Palmitoyltransferase
  • Glucose