Apr3 accelerates the senescence of human retinal pigment epithelial cells

Abstract

Senescence of retinal pigment epithelium (RPE) cells is a major contributor to age-related macular degeneration (AMD). However, the molecular mechanisms underlying RPE dysfunction are not well understood. Apoptosis related protein 3 (Apr3) was originally cloned from HL-60 cells induced by all-trans retinoic acid (ATRA). Preliminary data revealed elevated Apr3 expression in the tissues of aged mice, suggesting that it is involved in the aging process. The present study demonstrated that Apr3 mRNA and protein levels were markedly increased in aged mouse RPE cells. Elevated Apr3 expression was also observed during premature senescence induced by oxidative stress (H2O2 and tert-BHP) in ARPE-19 cells. Moreover, Apr3 overexpression promoted cellular senescence in ARPE-19 cells, as characterized by enhanced senescence-associated β-galactosidase activity, reduced cell proliferation and increased expression of the senescence markers p53 and p21. In addition, it was demonstrated that overexpression of Apr3-N, a truncated counterpart of Apr3, abrogated Apr3-induced phenotypes. It was concluded that Apr3 expression was induced in replicative and premature senescence of RPE cells and its overexpression accelerated senescence of ARPE-19 cells, which provides important insights into the function of Apr3 in senescence-associated diseases.