Endoplasmic reticulum stress induced by oxidative stress in retinal pigment epithelial cells

Graefes Arch Clin Exp Ophthalmol. 2008 May;246(5):677-83. doi: 10.1007/s00417-008-0770-2. Epub 2008 Feb 16.

Abstract

Background: Induction of glucose-regulated protein (GRP)-78 in the endoplasmic reticulum (ER) is a protective mechanism cells use to adapt to ER stress. We evaluated the expression of GRP-78 and its regulation by an oxidant tert-butyl hydroperoxide (tBH) in human retinal pigment epithelium (RPE) cells.

Methods: We used a carboxy-H2-DCFDA staining method to detect tBH-induced accumulation of reactive oxygen species (ROS) in RPE cells, and analyzed the expression of GRP-78 in normal human fetal and adult retinas and in cultured human RPE cells by immunohistochemistry. The effects of tBH (10-100 microM) on GRP-78 and on growth arrest and DNA damage inducible genes 153 (GADD153) protein and mRNA expression were studied using Western blot and real-time polymerase chain reaction.

Results: Sections of fetal retinas were negative for GRP-78. Adult retinas showed moderate cytoplasmic GRP-78 staining in the RPE and choroid. tBH-induced ROS accumulation in RPE cells showed partial colocalization with the ER. GRP-78 and GADD153 mRNA and protein expression in cultured RPE cells were significantly upregulated by treatment with tBH.

Conclusion: tBH increases oxidative stress, increases accumulation of ROS in the ER, and upregulates expression of GRP-78 and GADD153. This supports the connection between oxidative stress and ER stress, and suggests that GRP-78 may serve a protective role in the RPE response to oxidative stress.

Publication types

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

MeSH terms

  • Aged
  • Aged, 80 and over
  • Blotting, Western
  • Cells, Cultured
  • Endoplasmic Reticulum / drug effects*
  • Endoplasmic Reticulum / metabolism
  • Fetus / cytology
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism*
  • Humans
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Oxidative Stress / drug effects*
  • Pigment Epithelium of Eye / drug effects*
  • Pigment Epithelium of Eye / metabolism
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factor CHOP / genetics
  • Transcription Factor CHOP / metabolism*
  • Up-Regulation
  • tert-Butylhydroperoxide / pharmacology*

Substances

  • DDIT3 protein, human
  • Heat-Shock Proteins
  • Molecular Chaperones
  • RNA, Messenger
  • Reactive Oxygen Species
  • Transcription Factor CHOP
  • tert-Butylhydroperoxide
  • molecular chaperone GRP78