Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, 10 Center Dr., 10/10N103, NIH/NEI, Bethesda, MD 20892-1857, USA.
Apoptosis. 2012 Nov;17(11):1144-55. doi: 10.1007/s10495-012-0750-1.
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.
年龄相关性黄斑变性（AMD）是一种神经退行性疾病，可导致老年人不可逆转的中心视力丧失。视网膜色素上皮（RPE）已被发现是 AMD 发病机制中的关键组成部分。在 Crb1(rd8) 背景下的 Ccl2(-/-)/Cx3cr1(-/-)（DKO）小鼠被创建为 AMD 模型，可发展出类似 AMD 的视网膜病变。我们的研究旨在研究 DKO 小鼠和人 ARPE-19 细胞系中的 RPE 细胞凋亡。在生理条件下，与年龄匹配的野生型（WT）RPE 相比，DKO RPE 表达更高的凋亡蛋白。在脂多糖刺激下评估原代培养的小鼠 RPE 的凋亡，以进行炎症刺激，以及 2,3,7,8-四氯二苯并-p-二恶英或 H(2)O(2) 进行氧化应激。与 WT RPE 相比，DKO RPE 在炎症和氧化应激下更容易受到 Fas 配体（FasL）介导的凋亡，细胞活力较低，凋亡转录物和蛋白质表达较高。在每种刺激下，ARPE-19 细胞的细胞活力也降低。此外，我们还研究了 FasL 的诱饵受体 3（DcR3）对炎症和氧化应激下 ARPE-19 细胞的抗凋亡作用。在刺激下，预先孵育 DcR3 的 ARPE-19 细胞显示出凋亡减少，细胞活力增加，凋亡转录物和蛋白质表达减少。相反，在 ARPE-19 细胞中敲低 DcR3 则显示出完全相反的结果。我们的研究表明，FasL 介导的 RPE 细胞凋亡可能在 AMD 发病机制中起关键作用。
