Protection from oxidative stress by methionine sulfoxide reductases in RPE cells.
We investigated the role of methionine sulfoxide reductases (Msrs) in oxidant-stress-induced cell death in retinal pigmented epithelial (RPE) cells. In RPE cells exposed to varying doses of H(2)O(2), gene expression of MsrA and hCBS-1 (the human analog of MsrB2) increased in a dose-dependent and time-dependent manner with maximal increase with 150 microM H(2)O(2) in 24h. H(2)O(2) treatment resulted in the generation of reactive oxygen species and activation of caspase 3. Confocal microscopic and protein analysis showed an increase in MsrA expression in cytosol and mitochondria. Silencing of MsrA resulted in caspase 3 induction and accentuated cell death from H(2)O(2). Focal, strong immunoreactivity for MsrA was observed in sub-RPE macular drusen from patients with age-related macular degeneration. In summary, our data show that MsrA and hCBS-1 are up-regulated in oxidative stress to counteract injury to RPE.
Sreekumar
Parameswaran G
PG
Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA.
Kannan
Ram
R
Yaung
Jennifer
J
Spee
Christine K
CK
Ryan
Stephen J
SJ
Hinton
David R
DR
D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage*; D008268:Macular Degeneration / Q000378:metabolism*; D051150:Methionine Sulfoxide Reductases; D008840:Microfilament Proteins; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010088:Oxidoreductases / Q000378:metabolism*; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
D008840:Microfilament Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C120376:MSRB2 protein, human; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase