Functional studies of DICER1 and Alu RNA in geographic atrophy

描述（由申请人提供）：地理萎缩（GA）是一种无法治疗的晚期老年性黄斑变性（AMD），其特征是视网膜色素上皮（RPE）变性。无论是促进这种RPE变性的机制，还是最终导致失明的GA离心膨胀的基础都没有得到解决。GA发病机制的这种神秘性质阻碍了fda批准的任何针对100万确诊为GA的美国人和数百万有患GA风险的美国人的治疗。在新的和令人兴奋的研究中，我们发现了一个令人惊讶的发现，即在GA人眼的RPE中存在大量的Alu重复RNA，这种重复RNA在RNase DICER1显著缺乏的情况下积累，并诱导RPE变性（Kaneko等）。自然2011)。我们的研究结果，介绍了DICER1独立于其标准miRNA生物发生功能的一种新的细胞存活功能，以及Alu RNA可以直接促进人类病理的概念，为GA发病机制提供了新的机制见解。然而，我们仍然缺乏对DICER1在GA中如何失调以及Alu RNA如何诱导RPE变性的综合理解。严格定义这些机制对于加强我们对GA分子驱动因素的理解和制定合理的治疗方法至关重要。我们将通过以下目标为DICER1/Alu RNA失调如何促进GA发病提供新的功能见解，并开发新的治疗策略：(1)生成与GA和早期AMD眼睛病理位点相关的DICER1和Alu RNA的时空图谱；(2)破译Alu RNA触发我们已经确定的新的炎症细胞死亡途径的机制；(3)明确遗传背景下DICER1在RPE中的分子调控以及DICER1新剪接变异体的功能；(4)建立具有类人特征的GA动物模型，验证针对Alu RNA的反义治疗策略。这些研究将阐明GA分子和生化基础的新方面，并有助于验证可转化为临床试验的分子靶向策略。因此，该提案完全符合NEI视网膜疾病项目战略计划的5年目标。

DESCRIPTION (provided by applicant): 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.