Retinal pigment epithelial cells undergoing mitotic catastrophe are vulnerable to autophagy inhibition

Cell Death Dis. 2014 Jun 26;5(6):e1303. doi: 10.1038/cddis.2014.266.

Abstract

The increased mitochondrial DNA damage leads to altered functional capacities of retinal pigment epithelial (RPE) cells. A previous study showed the increased autophagy in RPE cells caused by low concentrations of rotenone, a selective inhibitor of mitochondrial complex I. However, the mechanism by which autophagy regulates RPE cell death is still unclear. In the present study, we examined the mechanism underlying the regulation of RPE cell death through the inhibition of mitochondrial complex I. We report herein that rotenone induced mitotic catastrophe (MC) in RPE cells. We further observed an increased level of autophagy in the RPE cells undergoing MC (RPE-MC cells). Importantly, autophagy inhibition induced nonapoptotic cell death in RPE-MC cells. These findings indicate that autophagy has a pivotal role in the survival of RPE-MC cells. We next observed PINK1 accumulation in the mitochondrial membrane and parkin translocation into the mitochondria from the cytosol in the rotenone-treated RPE-MC cells, which indicates that increased mitophagy accompanies MC in ARPE-19 cells. Noticeably, the mitophagy also contributed to the cytoprotection of RPE-MC cells. Although there might be a significant gap in the roles of autophagy and mitophagy in the RPE cells in vivo, our in vitro study suggests that autophagy and mitophagy presumably prevent the RPE-MC cells from plunging into cell death, resulting in the prevention of RPE cell loss.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy / physiology*
  • Cell Line
  • Cell Survival / physiology
  • Electron Transport Complex I / metabolism*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Humans
  • Mitochondria / metabolism*
  • Mitosis / physiology*
  • Protein Transport / physiology
  • Retinal Pigment Epithelium / cytology
  • Retinal Pigment Epithelium / metabolism*
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • Ubiquitin-Protein Ligases
  • parkin protein
  • Electron Transport Complex I