Functional studies of DICER1 and Alu RNA in geographic atrophy

摘要 地理性萎缩(GA)是一种无法治疗的老年性黄斑变性的晚期形式 (AMD)，以视网膜色素上皮(RPE)变性为特征。都不是 促进这种RPE退化的机制或离心式膨胀的基础 最终可能导致失明的GA的问题已经得到解决。GA的这一神秘性质 发病机制已经排除了FDA批准的针对100万人的任何治疗方法的开发 美国人被诊断出患有GA，还有数百万人面临患GA的风险。在新的和 在令人兴奋的研究中，我们做出了令人惊讶的观察，即存在大量的Alu重复 患有GA的人眼RPE中对戏剧性缺陷的反应而积聚的RNA 在RNase DICER1中，并诱导RPE变性(Kaneko等人)。《自然》2011)。我们的 这些发现为DICER1引入了一种新的细胞存活函数，该函数独立于其规范的 MiRNA的生物发生功能和Alu RNA可直接促进人类 病理学，为GA的发病机制提供了新的机制见解。然而，我们仍然缺乏一个 对DICER1在GA中如何失调以及Alu RNA如何精确调控的综合理解 导致RPE变性。对这些机制的严格定义对于增强 我们对GA的分子驱动因素的理解和开发合理的治疗方法。我们会 为DICER1/Alu RNA失调如何导致GA提供新的功能见解 发病机制并通过以下目的开发新的治疗策略：(1)产生一种 DICER1和Alu RNA的时空图与GA和 早期AMD眼睛；(2)破译Alu RNA引发新的炎症反应的机制 我们已经确定了细胞死亡途径；(3)确定了DICER1在细胞中的分子调控 RPE在GA背景下的作用和一种新的DICER1剪接变异体；(4)创建新的 具有与人类相似的疾病特征的GA动物模型和反义验证 针对Alu RNA的治疗策略。这些研究将阐明 GA的分子和生化基础，并帮助验证分子靶向策略 可以转化为临床试验。因此，这项提议与5年期完全一致 NEI的视网膜疾病计划战略计划的目标。

Summary Geographic atrophy (GA) is an untreatable advanced form of age-related macular degeneration (AMD) that is characterized by degeneration of the retinal pigmented epithelium (RPE). Neither the mechanisms that promote this RPE degeneration nor the basis for the centrifugal expansion of GA that can ultimately lead to blindness have been resolved. This enigmatic nature of GA pathogenesis has precluded the development of any FDA-approved therapy for the one million Americans diagnosed with GA and the millions more at risk of developing GA. In new and exciting studies, we made the surprising observation that there is an abundance of Alu repetitive RNA in the RPE of human eyes with GA that accumulates in response to a dramatic deficiency in the RNase DICER1 and induces RPE degeneration (Kaneko et al. Nature 2011). Our findings, which introduce a novel cell survival function for DICER1 independent of its canonical miRNA biogenesis function and the concept that Alu RNA can directly promote human pathology, provide new mechanistic insights into GA pathogenesis. However, we still lack an integrated understanding of how DICER1 is dysregulated in GA and precisely how Alu RNA induces RPE degeneration. A rigorous definition of these mechanisms is crucial to enhancing our understanding of the molecular drivers of GA and to developing rational treatments. We will provide novel functional insights into how DICER1/Alu RNA dysregulation contributes to GA pathogenesis and develop a novel therapeutic strategy via the following Aims: (1) Generate a spatiotemporal map of DICER1 and Alu RNA in relation to the locus of pathology in GA and early AMD eyes; (2) Decipher the mechanisms by which Alu RNA triggers a new inflammatory cell death pathway we have identified; (3) Define the molecular regulation of DICER1 in the RPE in the context of GA and the function of a novel DICER1 splice variant; (4) Create a new animal model of GA having human-like features of the disease and validate an antisense therapeutic strategy targeting Alu RNA. These studies will illuminate novel aspects of the molecular and biochemical bases of GA, and help validate a molecular targeting strategy that could be translated into clinical trials. As such, this proposal is perfectly aligned with the 5-year goals of the NEI's Retinal Diseases Program strategic plan.