Reactive oxygen species-mediated endoplasmic reticulum stress contributes to aldosterone-induced apoptosis in tubular epithelial cells

Biochem Biophys Res Commun. 2012 Feb 17;418(3):451-6. doi: 10.1016/j.bbrc.2012.01.037. Epub 2012 Jan 18.

Abstract

Apoptosis contributes to tubular epithelial cell death and atrophy in aldosterone (Aldo)-induced renal injury. This study aimed to determine mechanisms underlying Aldo-induced reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress in tubular epithelial cells. Intracellular ROS generation was evaluated by 2',7'-dichlorofluorescin diacetate fluorescence. Apoptosis was detected by annexin V/propidium iodide staining and flow cytometry. ER stress induced protein and mRNA were evaluated by Western blot and real-time PCR, respectively. Aldo promoted tubular epithelial cell apoptosis, increased intracellular ROS production and induced ER stress, as evidenced by increased expression of glucose-regulated protein 78 (GRP78) and CAAT/enhancer-binding protein homologous protein (CHOP) in a dose- and time-dependent manner. Additionally, siRNA knockdown of CHOP and antioxidant N-acetyl-l-cysteine (NAC) attenuated ER stress-mediated apoptosis. NAC also could inhibit Aldo-induced expression of GRP78 and CHOP. Altogether, these observations suggest that Aldo induces apoptosis via ROS-mediated, CHOP-dependent activation in renal tubular epithelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcysteine / pharmacology
  • Aldosterone / pharmacology
  • Aldosterone / physiology*
  • Annexin A5 / chemistry
  • Antioxidants / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Cell Line
  • Endoplasmic Reticulum Chaperone BiP
  • Endoplasmic Reticulum Stress*
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / physiology
  • Fluoresceins / chemistry
  • Heat-Shock Proteins / biosynthesis
  • Humans
  • Kidney Tubules / cytology
  • Kidney Tubules / drug effects
  • Kidney Tubules / physiology*
  • Propidium / chemistry
  • RNA, Small Interfering / genetics
  • Reactive Oxygen Species / metabolism*
  • Transcription Factor CHOP / biosynthesis
  • Transcription Factor CHOP / genetics

Substances

  • Annexin A5
  • Antioxidants
  • DDIT3 protein, human
  • Endoplasmic Reticulum Chaperone BiP
  • Fluoresceins
  • HSPA5 protein, human
  • Heat-Shock Proteins
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Transcription Factor CHOP
  • diacetyldichlorofluorescein
  • Propidium
  • Aldosterone
  • Acetylcysteine