Enhanced apoptosis in retinal pigment epithelium under inflammatory stimuli and oxidative stress

Apoptosis. 2012 Nov;17(11):1144-55. doi: 10.1007/s10495-012-0750-1.

Abstract

Age-related macular degeneration (AMD) is a neurodegenerative disease that causes irreversible central vision loss in the elderly. Retinal pigment epithelium (RPE) has been found to be a key component in AMD pathogenesis. The Ccl2(-/-)/Cx3cr1(-/-) (DKO) mouse on Crb1(rd8) background is created as an AMD model, developing AMD-like retinal lesions. Our study aimed to examine RPE apoptosis in DKO mouse and human ARPE-19 cell line. DKO RPE expressed higher apoptotic proteins when compared with age-matched wild type (WT) RPE in physiological conditions. Apoptosis of primary cultured mouse RPE was evaluated under stimulation with lipopolysaccharide for inflammatory stimulation and 2,3,7,8-tetrachlorodibenzo-p-dioxin or H(2)O(2) for oxidative stress. Compared with WT RPE, DKO RPE was more susceptible to Fas ligand (FasL)-mediated apoptosis under both inflammatory and oxidative stress, with less cell viability and higher expression of apoptotic transcripts and proteins. Decreased cell viability was also observed in ARPE-19 cells under each stimulus. Furthermore, we also investigated the anti-apoptotic effects of decoy receptor 3 (DcR3), a decoy receptor for FasL, on ARPE-19 cells under inflammatory and oxidative stress. DcR3 pre-incubated ARPE-19 cells showed decreased apoptosis, with increased cell viability and decreased expression of apoptotic transcripts and proteins under the stimuli. On the contrary, knockdown of DcR3 in ARPE-19 cells showed totally opposite results. Our study demonstrates that FasL-mediated RPE apoptosis may play a pivotal role in AMD pathogenesis.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Apoptosis* / drug effects
  • Cells, Cultured
  • Gene Knockdown Techniques
  • Humans
  • Inflammation / pathology*
  • Lipopolysaccharides / pharmacology
  • Mice
  • Mice, Knockout
  • Microscopy, Fluorescence
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondria / pathology
  • Oxidative Stress* / drug effects
  • Polychlorinated Dibenzodioxins / pharmacology
  • RNA, Small Interfering / metabolism
  • Receptors, Tumor Necrosis Factor, Member 6b / metabolism
  • Retinal Pigment Epithelium / drug effects
  • Retinal Pigment Epithelium / metabolism
  • Retinal Pigment Epithelium / pathology*

Substances

  • Lipopolysaccharides
  • Polychlorinated Dibenzodioxins
  • RNA, Small Interfering
  • Receptors, Tumor Necrosis Factor, Member 6b
  • TNFRSF6B protein, human