Inhibition of autophagy induces retinal pigment epithelial cell damage by the lipofuscin fluorophore A2E

Khandakar A.S.M. Saadat, Yusuke Murakami, Xue Tan, Yoko Nomura, Tsutomu Yasukawa, Eiichi Okada, Yasuhiro Ikeda, Yasuo Yanagi

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

In this study, we show augmented autophagy in the retinal pigment epithelial cell line ARPE-19 when cultured in the presence of the lipofuscin pigment A2E. A2E alone does not induce RPE cell death, but cell death was induced in the presence of A2E with the autophagy inhibitor 3-methyladenine (3MA), with a concomitant increase in the generation of mitochondrial reactive oxygen species. On the other hand, the ATP production capacity of mitochondria was decreased in the presence of A2E, and pharmacological inhibition of autophagy had no additional effects. The altered mRNA expression level of mitochondrial function markers was confirmed by real-time polymerase chain reaction, which showed that the antioxidant enzymes SOD1 and SOD2 were not reduced in the presence of A2E alone, but significantly suppressed with the addition of 3MA. Furthermore, transmission electron micrography revealed autophagic vacuole formation in the presence of A2E, and inhibition of autophagy resulted in the accumulation of abnormal mitochondria with loss of cristae. Spheroid culture of human RPE cells demonstrated debris accumulation in the presence of A2E, and this accumulation was accelerated in the presence of 3MA. These results indicate that autophagy in RPE cells is a vital cytoprotective process that prevents the accumulation of damaged cellular molecules.

Original languageEnglish
Pages (from-to)1007-1014
Number of pages8
JournalFEBS Open Bio
Volume4
DOIs
Publication statusPublished - Dec 1 2014

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Lipofuscin
Retinal Pigments
Fluorophores
Autophagy
Mitochondria
Epithelial Cells
Cell death
Polymerase chain reaction
Cell culture
Debris
Pigments
Cell Death
Reactive Oxygen Species
Antioxidants
Adenosine Triphosphate
Messenger RNA
Vacuoles
Molecules
Electrons
Enzymes

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Inhibition of autophagy induces retinal pigment epithelial cell damage by the lipofuscin fluorophore A2E. / Saadat, Khandakar A.S.M.; Murakami, Yusuke; Tan, Xue; Nomura, Yoko; Yasukawa, Tsutomu; Okada, Eiichi; Ikeda, Yasuhiro; Yanagi, Yasuo.

In: FEBS Open Bio, Vol. 4, 01.12.2014, p. 1007-1014.

Research output: Contribution to journalArticle

Saadat, Khandakar A.S.M. ; Murakami, Yusuke ; Tan, Xue ; Nomura, Yoko ; Yasukawa, Tsutomu ; Okada, Eiichi ; Ikeda, Yasuhiro ; Yanagi, Yasuo. / Inhibition of autophagy induces retinal pigment epithelial cell damage by the lipofuscin fluorophore A2E. In: FEBS Open Bio. 2014 ; Vol. 4. pp. 1007-1014.
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