Prevention of Retinal Degeneration by Crystallins in Experimental Uveitis

晶状体蛋白预防实验性葡萄膜炎中的视网膜变性

• 批准号: 7680016
• 负责人: NARSING A RAO
• 金额: $ 38.98万
• 依托单位: DOHENY EYE INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7680016
• 关键词: Age related macular degeneration; Animal Model; Antigens; Apoptosis; Apoptotic; Autoimmune Process; Blindness; Caspase; Cell Death; Crystallins; Cytochromes; Cytosol; Data; Disease; Eye; Glaucoma; Heat Shock Protein 27; Heat shock proteins; Histologic; Human; Immune; Infiltration; Inflammation; Knockout Mice; Leukocytes; Mediating; Mitochondria; Molecular; Mus; Nitrates; Oxidative Stress; Oxidative Stress Induction; Phase; Photoreceptors; Prevention; Principal Investigator; Proteins; Retina; Retinal Degeneration; Retinal Photoreceptors; Retinal Vein Occlusion; S cerevisiae HSP12 protein; T-Lymphocyte; TNF gene; Testing; Therapeutic Agents; Tissues; Up-Regulation; Uveitis; Wild Type Mouse; autoimmune uveitis; base; cytochrome c; cytokine; macrophage; neutrophil; nitration; novel; oxidative damage; prevent; public health relevance; response; uveoretinitis

DESCRIPTION (provided by principal investigator): Intraocular inflammation, commonly referred to as uveitis, is a leading cause of blindness from retinal photoreceptor cell apoptosis. A robust animal model of uveitis that closely resembles human uveitis is experimental autoimmune uveoretinitis (EAU). It is characterized by two phases: the early phase, 5-7 days postimmunization (p.i.) with an uveitogenic antigen, and the late/amplification phase, 12-14 days p.i. During the late phase, macrophages/neutrophils infiltrate the retina, and photoreceptor damage is noted histologically. The early phase, preceding the leukocyte infiltration, reveals Th1- and Th17-driven cytokines in the retina, nitration of cytochrome c (cyto c) in the photoreceptors from mitochondrial oxidative stress, and the release of nitrated cyto c into the cytosol. Such cyto c release is known to cause apoptosis. However, apoptosis is not a feature of early EAU, suggesting the presence of a protective mechanism(s) in the EAU retina that prevents photoreceptor apoptosis. Current preliminary studies suggest that the protection is offered by 1A crystallin upregulation and that this is unique to the photoreceptors and are not mediated by well-recognized anti-apoptotic proteins, including 1B crystallin, heat shock protein 27 and other heat shock proteins. Significantly, 1A crystallin knockout mice with early EAU show prominent apoptosis in the retina; such apoptosis is totally absent in the wild type mice with EAU. The data reveal the significance of 1A crystallin in preventing apoptosis in the retina. Moreover, it indicates that unlike other tissues, the photoreceptors utilize 1A crystallins selectively in the prevention of oxidative stress-mediated damage in early EAU, a novel protective mechanism observed in the photoreceptors. Based on our preliminary studies we hypothesize that 1) upregulation of 1A crystallin is a feature of the photoreceptors in response to mitochondrial oxidative stress; 2) upregulated 1A crystallin interacts with the oxidative stress-induced nitrated cyto c, blocking the activation of caspases, and preventing apoptosis of photoreceptors. These hypotheses will be tested by three specific aims: 1) Determine the immune mechanism of 1A crystallin upregulation in the retina during EAU; 2) Determine prevention of photoreceptor apoptosis by 1A crystallin in EAU and 3) Determine photoreceptor oxidative stress induction by iNOS in EAU. In-depth analysis of the immune mechanism(s) of 1A crystallin upregulation in EAU and its protective anti- apoptotic function will enhance our understanding, by clarifying the importance of crystallin upregulation in photoreceptor protection not only in uveitis, but in other oxidative stress-mediated retinal degenerations as well. Moreover the current proposal suggests that 1A crystallin can be a promising therapeutic agent for preventing oxidative stress-mediated photoreceptor damage. Such oxidative damage has been implicated in various blinding diseases, including age-related macular degeneration, retinal vein occlusion, and glaucoma. PUBLIC HEALTH RELEVANCE AlphaA crystallin is a unique protein present in the eye and other tissues. Lack of this protein can cause blindness, and supplement of this protein can prevent several blinding diseases.

描述（由主要研究者提供）：眼内炎症通常称为葡萄膜炎，是视网膜感光细胞细胞凋亡引起失明的主要原因。非常类似于人葡萄膜炎的葡萄膜炎的强大动物模型是实验性自身免疫性葡萄膜炎（EAU）。它的特征是两个阶段：早期阶段，以卵形抗原为基础5-7天（P.I.），晚期/扩增阶段，12-14天P.I.在后期，巨噬细胞/中性粒细胞浸润视网膜，并在组织学上注意到感光器损伤。在白细胞浸润之前的早期阶段揭示了视网膜中的Th1-和Th17驱动的细胞因子，从线粒体氧化应激的光感受器中的细胞色素C（Cyto c）硝化，以及氮的细胞质C中的细胞质C中的细胞质释放。已知这种Cyto C释放会引起凋亡。然而，凋亡不是EAU早期的特征，表明在EAU视网膜中存在防护机制，可以防止感光细胞凋亡。当前的初步研究表明，保护是由1A结晶蛋白上调提供的，这是感光体特有的，并且不是由良好认可的抗凋亡蛋白（包括1B晶体蛋白，热休克蛋白27和其他热激蛋白）介导的。值得注意的是，与早期EAU的1A结晶敲除小鼠在视网膜中显示出明显的细胞凋亡。在使用EAU的野生型小鼠中，这种凋亡完全不存在。数据揭示了1A晶体在预防视网膜细胞凋亡方面的重要性。此外，这表明与其他组织不同，感光体在预防早期EAU中选择性地利用1A晶体，以预防氧化应激介导的损伤，EAU是一种在感光体中观察到的新型保护机制。基于我们的初步研究，我们假设1）1a晶体蛋白的上调是感光体的特征，响应线粒体氧化应激； 2）上调的1A结晶蛋白与氧化应激诱导的硝化的Cyto C相互作用，阻断胱天蛋白酶的激活，并防止感光体的细胞凋亡。这些假设将通过三个特定目的来检验：1）确定EAU期间视网膜中1A结晶蛋白上调的免疫机制； 2）确定EAU中1A晶体蛋白通过1A晶体的预防感光细胞凋亡，并确定iNOS在EAU中诱导感光受体氧化应激。对EAU中1A结晶蛋白上调的免疫机制的深入分析及其保护性抗凋亡功能将通过阐明晶体蛋白上调在光感受器保护中的重要性，不仅在葡萄膜炎中，而且在其他氧化应激介导的视网膜上也可以增强我们的理解。此外，目前的建议表明，1A结晶蛋白可以是预防氧化应激介导的感光体损伤的有前途的治疗剂。这种氧化损伤与各种盲目疾病有关，包括与年龄相关的黄斑变性，视网膜静脉阻塞和青光眼。公共卫生相关性αAaCrystallin是眼睛和其他组织中存在的独特蛋白质。缺乏这种蛋白质会引起失明，补充这种蛋白质可以防止多种盲目疾病。