The roles of oxidative stress, endoplasmic reticulum stress, and autophagy in aldosterone/mineralocorticoid receptor-induced podocyte injury

Lab Invest. 2015 Dec;95(12):1374-86. doi: 10.1038/labinvest.2015.118. Epub 2015 Sep 28.

Abstract

Podocytes play an important role in the pathogenesis and progression of glomerulosclerosis. Recent studies indicate that aldosterone/mineralocorticoid receptor (MR) is a major contributor of chronic kidney disease (CKD) progression. Aldosterone/MR induces glomerular podocyte injury, causing the disruption of the glomerular filtration barrier and proteinuria. The present study investigated the mechanisms by which aldosterone/MR mediated podocyte injury, focusing on the involvement of oxidative stress, endoplasmic reticulum (ER) stress, and autophagy. We observed that aldosterone/MR induced ER stress and podocyte injury both in vivo and in vitro. Blockade of ER stress significantly reduced aldosterone/MR-induced podocyte injury. In addition, we found that ER stress-induced podocyte injury was mediated by CCAAT/enhancer-binding protein (C/EBP) homologous protein (Chop). Interestingly, autophagy was also enhanced by aldosterone/MR. Pharmacological inhibition of autophagy resulted in increased apoptosis. Inhibition of ER stress significantly reduced aldosterone/MR-induced autophagy. In addition, the activation of ER stress increased the formation of autophagy, which protected podocytes from apoptosis. Moreover, we observed that the addition of ROS scavenger, N-acetyl cystein (NAC), blocked both ER stress and autophagy by aldosterone/MR. Collectively, these results suggest that oxidant stress-mediated aldosterone/MR-induced podocyte injury via activating ER stress, which then triggers both Chop-dependent apoptosis and autophagy to cope with the injury. These findings may guide us to therapeutic strategies for glomerular diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldosterone / metabolism*
  • Animals
  • Autophagy*
  • Cells, Cultured
  • Endoplasmic Reticulum Stress*
  • Kidney Diseases / etiology*
  • Male
  • Mice, Inbred C57BL
  • Oxidative Stress*
  • Podocytes / physiology*
  • Reactive Oxygen Species / metabolism
  • Receptors, Mineralocorticoid / metabolism
  • Transcription Factor CHOP / metabolism

Substances

  • Ddit3 protein, mouse
  • Reactive Oxygen Species
  • Receptors, Mineralocorticoid
  • Transcription Factor CHOP
  • Aldosterone