Hydrogen peroxide causes significant mitochondrial DNA damage in human RPE cells.
Retinal pigment epithelial cell dysfunction mediated by reactive oxygen intermediates has been suggested as a possible cause of age-related macular degeneration. To test the hypothesis that retinal pigment cells are susceptible to genetic damage mediated by reactive oxygen intermediates, retinal pigment epithelial cells were treated with 50 micrometers-200 micrometers of hydrogen peroxide in vitro. Damage to mitochondrial DNA and three nuclear loci were assessed using quantitative polymerase chain reaction. Hydrogen peroxide treatment of retinal pigment epithelial cells resulted in significantly increased mitochondrial DNA damage. Significant mitochondrial DNA damage occurred rapidly and was not completely repaired within 3 hr post-treatment. By contrast, no DNA damage was observed in three different nuclear loci (beta-globin gene cluster, hprt, and beta- polymerase genes). Hydrogen peroxide treatment of retinal pigment epithelial cells also resulted in decreased mitochondrial redox function compared to controls, consistent with increased mitochondrial DNA damage. Consequently, retinal pigment epithelial cell mitochondrial DNA appears susceptible to hydrogen peroxide mediated damage in vitro, and thus, may serve as a catalyst in the initial events leading to retinal pigment epithelial cell dysfunction in vivo.
Ballinger
S W
SW
Sealy Center for Molecular Cardiology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
Van Houten
B
B
Jin
G F
GF
Conklin
C A
CA
Godley
B F
BF
D018929:Cell Culture Techniques; D004249:DNA Damage; D004260:DNA Repair; D004272:DNA, Mitochondrial / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D010084:Oxidation-Reduction / Q000187:drug effects; D010857:Pigment Epithelium of Eye / Q000187:drug effects*; D016133:Polymerase Chain Reaction
D004272:DNA, Mitochondrial; D006861:Hydrogen Peroxide