A critical role for eukaryotic elongation factor 1A-1 in lipotoxic cell death

Mol Biol Cell. 2006 Feb;17(2):770-8. doi: 10.1091/mbc.e05-08-0742. Epub 2005 Nov 30.

Abstract

The deleterious consequences of fatty acid (FA) and neutral lipid accumulation in nonadipose tissues, such as the heart, contribute to the pathogenesis of type 2 diabetes. To elucidate mechanisms of FA-induced cell death, or lipotoxicity, we generated Chinese hamster ovary (CHO) cell mutants resistant to palmitate-induced death and isolated a clone with disruption of eukaryotic elongation factor (eEF) 1A-1. eEF1A-1 involvement in lipotoxicity was confirmed in H9c2 cardiomyoblasts, in which small interfering RNA-mediated knockdown also conferred palmitate resistance. In wild-type CHO and H9c2 cells, palmitate increased reactive oxygen species and induced endoplasmic reticulum (ER) stress, changes accompanied by increased eEF1A-1 expression. Disruption of eEF1A-1 expression rendered these cells resistant to hydrogen peroxide- and ER stress-induced death, indicating that eEF1A-1 plays a critical role in the cell death response to these stressors downstream of lipid overload. Disruption of eEF1A-1 also resulted in actin cytoskeleton defects under basal conditions and in response to palmitate, suggesting that eEF1A-1 mediates lipotoxic cell death, secondary to oxidative and ER stress, by regulating cytoskeletal changes critical for this process. Furthermore, our observations of oxidative stress, ER stress, and induction of eEF1A-1 expression in a mouse model of lipotoxic cardiomyopathy implicate this cellular response in the pathophysiology of metabolic disease.

Publication types

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

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Cardiomyopathies / chemically induced
  • Cardiomyopathies / metabolism
  • Cell Death
  • Cell Line
  • Cricetinae
  • Cricetulus
  • Disease Models, Animal
  • Endoplasmic Reticulum / physiology
  • Mice
  • Models, Biological
  • Mutagenesis, Insertional
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism*
  • Oxidative Stress
  • Palmitates / toxicity*
  • Peptide Elongation Factor 1 / metabolism
  • Peptide Elongation Factor 1 / physiology*
  • RNA Interference
  • Rats
  • Reactive Oxygen Species / metabolism

Substances

  • Biomarkers
  • Palmitates
  • Peptide Elongation Factor 1
  • Reactive Oxygen Species