Age-related increase in mitochondrial DNA damage and loss of DNA repair capacity in the neural retina

Ai Ling Wang*, Thomas J. Lukas, Ming Yuan, Arthur H. Neufeld

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

With age, there is increased mitochondrial DNA (mtDNA) damage in the central nervous system (CNS) that may underlie, contribute or increase the susceptibility to certain neurodegenerative diseases. We examined retinas from the eyes of young and old rodents for mtDNA damage and for changes in selected DNA repair enzymes. We found increased levels of 8-hydroxy-2′-deoxy-guanosine (8-OHdG) by immunohistochemical labeling for the oxidative DNA damage marker in aged rodent retinas, which was confirmed by quantitative ELISA. 8-OHdG co-localized with the mitochondrial enzyme superoxide dismutase (MnSOD), suggesting damage to mtDNA. Most of the damaged mtDNA was in the photoreceptors and retinal ganglion cells. Measurements of nuclear DNA (nDNA) and mtDNA lesions indicated that DNA damage was primarily in mtDNA in aged retinas. The increased damage to mtDNA may be due to decreased levels of DNA repair enzymes in the aged retina. Using qPCR, Western blots and immunohistochemistry, we determined the levels of DNA repair enzymes for oxidative damage. In retinas from old eyes compared to retinas from young eyes, we found decreased levels of poly (ADP-ribose) polymerase 1 (PARP1), mutY homolog (MYH) and endonuclease III homologue 1 (NTH1). Our results suggest that normal, age-related, increased mtDNA damage, likely due to decreased repair capacity in aged retinas, may be a susceptibility factor that underlies age-related retinal diseases.

Original languageEnglish (US)
Pages (from-to)2002-2010
Number of pages9
JournalNeurobiology of Aging
Volume31
Issue number11
DOIs
StatePublished - Nov 2010

Keywords

  • 8-OHdG
  • Base excision repair enzymes
  • Oxidative damage
  • Retina

ASJC Scopus subject areas

  • Neuroscience(all)
  • Aging
  • Clinical Neurology
  • Developmental Biology
  • Geriatrics and Gerontology

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