Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD

Sayak K. Mitter, Chunjuan Song, Xiaoping Qi, Haoyu Mao, Haripriya Rao, Debra Akin, Alfred Lewin, Maria Grant, William Dunn, Jindong Ding, Catherine Bowes Rickman, Michael Boulton

Research output: Contribution to journalArticle

150 Scopus citations

Abstract

Autophagic dysregulation has been suggested in a broad range of neurodegenerative diseases including agerelated macular degeneration (AMD). To test whether the autophagy pathway plays a critical role to protect retinal pigmented epithelial (RPE) cells against oxidative stress, we exposed ARPE-19 and primary cultured human RPE cells to both acute (3 and 24 h) and chronic (14 d) oxidative stress and monitored autophagy by western blot, PCR, and autophagosome counts in the presence or absence of autophagy modulators. Acute oxidative stress led to a marked increase in autophagy in the RPE, whereas autophagy was reduced under chronic oxidative stress. Upregulation of autophagy by rapamycin decreased oxidative stress-induced generation of reactive oxygen species (ROS), whereas inhibition of autophagy by 3-methyladenine (3-MA) or by knockdown of ATG7 or BECN1 increased ROS generation, exacerbated oxidative stress-induced reduction of mitochondrial activity, reduced cell viability, and increased lipofuscin. Examination of control human donor specimens and mice demonstrated an age-related increase in autophagosome numbers and expression of autophagy proteins. However, autophagy proteins, autophagosomes, and autophagy flux were significantly reduced in tissue from human donor AMD eyes and 2 animal models of AMD. In conclusion, our data confirm that autophagy plays an important role in protection of the RPE against oxidative stress and lipofuscin accumulation and that impairment of autophagy is likely to exacerbate oxidative stress and contribute to the pathogenesis of AMD.

Original languageEnglish (US)
Pages (from-to)1989-2005
Number of pages17
JournalAutophagy
Volume10
Issue number11
DOIs
StatePublished - Nov 1 2014

Keywords

  • Age-related macular degeneration
  • Aging
  • Autophagy
  • Oxidative stress
  • RPE

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

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    Mitter, S. K., Song, C., Qi, X., Mao, H., Rao, H., Akin, D., Lewin, A., Grant, M., Dunn, W., Ding, J., Rickman, C. B., & Boulton, M. (2014). Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD. Autophagy, 10(11), 1989-2005. https://doi.org/10.4161/auto.36184