Regulation of podocyte survival and endoplasmic reticulum stress by fatty acids

Am J Physiol Renal Physiol. 2010 Oct;299(4):F821-9. doi: 10.1152/ajprenal.00196.2010. Epub 2010 Jul 28.

Abstract

Apoptosis of podocytes is considered critical in the pathogenesis of diabetic nephropathy (DN). Free fatty acids (FFAs) are critically involved in the pathogenesis of diabetes mellitus type 2, in particular the regulation of pancreatic β cell survival. The objectives of this study were to elucidate the role of palmitic acid, palmitoleic, and oleic acid in the regulation of podocyte cell death and endoplasmic reticulum (ER) stress. We show that palmitic acid increases podocyte cell death, both apoptosis and necrosis of podocytes, in a dose and time-dependent fashion. Palmitic acid induces podocyte ER stress, leading to an unfolded protein response as reflected by the induction of the ER chaperone immunoglobulin heavy chain binding protein (BiP) and proapoptotic C/EBP homologous protein (CHOP) transcription factor. Of note, the monounsaturated palmitoleic and oleic acid can attenuate the palmitic acid-induced upregulation of CHOP, thereby preventing cell death. Similarly, gene silencing of CHOP protects against palmitic acid-induced podocyte apoptosis. Our results offer a rationale for interventional studies aimed at testing whether dietary shifting of the FFA balance toward unsaturated FFAs can delay the progression of DN.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Caspase 3 / metabolism
  • Cell Survival / drug effects
  • Cells, Cultured
  • Endoplasmic Reticulum / drug effects*
  • Endoplasmic Reticulum / physiology
  • Fatty Acids, Monounsaturated / pharmacology*
  • Gene Silencing
  • Mice
  • Models, Animal
  • Oleic Acid / pharmacology*
  • Palmitic Acid / pharmacology*
  • Podocytes / cytology
  • Podocytes / drug effects*
  • Podocytes / metabolism
  • Stress, Physiological / physiology*
  • Transcription Factor CHOP / genetics
  • Transcription Factor CHOP / metabolism

Substances

  • Ddit3 protein, mouse
  • Fatty Acids, Monounsaturated
  • Transcription Factor CHOP
  • palmitoleic acid
  • Oleic Acid
  • Palmitic Acid
  • Caspase 3