Non-canonical inflammasome in activation in RPE degeneration

地图状萎缩（GA）是老年性黄斑变性（AMD）的一种晚期形式，是全球性的主要病因 影响超过一百万美国人的失明。在包括GA的许多病理特征中， 视网膜色素上皮（RPE）的变性是主要标志之一，这也是FDA- 注册临床试验的可接受终点。GA仍然是一个未满足的医疗需求，因为在很大程度上， 促进RPE退化的机制尚未完全解决。 早些时候，我们确定了GA眼睛的RPE中毒性非编码Alu RNA的特定积累， DICER 1缺乏（Nature 2011），通过激活经典的 半胱天冬酶-1炎性体（Cell 2012）。最近，我们阐明了信号交响乐， 细胞毒性：DICER 1破坏：Alu RNA稳态调节诱导非典型炎性小体 激活，一种由caspase-4/11介导的分子级联反应和一种新的非溶解性gasdermin D（GSDMD）， caspase-1的依赖性活化和IL-18的分泌（Nature Medicine 2018）。提高这些水平 在人类GA中也发现了分子，标志着它是第一个与人类疾病相关的非传染性疾病。 非典型炎性小体结合我们令人兴奋的初步数据，淀粉样蛋白β，另一个 视网膜色素上皮变性的触发因素，也激活了非典型炎性小体，这些发现表明， 非典型炎性小体可能是GA中驱动RPE变性的多种毒性信号的整合者。 考虑到炎性小体对细胞痛苦的无数触发做出反应，它可能代表了一个关键的 这是一个触发细胞死亡的检查点，因此是阻止RPE变性的有吸引力的靶点。但我们 仍然缺乏对GA中炎性小体激活以及它如何诱导RPE变性的综合理解。 对这些机制的严格定义对于增强我们对这些机制的分子驱动因素的理解至关重要。 遗传算法的这一标志和开发合理的治疗方法。我们将提供新的功能性见解， 失调的非典型炎性小体激活通过以下方式促成RPE变性 目的：（1）建立非典型炎性小体的空间图 （2）确定Gasdermin D（GSDMD）在非典型炎性小体中的作用 （3）确定靶向非经典炎性体途径是否改善RPE 在急性和慢性动物模型中的退化。这些研究将阐明新的方面的分子 和生化基础的RPE变性，并帮助验证分子靶向策略， 转化为临床试验。因此，该提案符合NEI视网膜疾病的5年目标 方案战略计划。

Geographic atrophy (GA), an advanced form of age-related macular degeneration (AMD), is a major global cause of blindness that affects more than 1 million Americans. Of the many pathological features that comprise GA, one of the cardinal hallmarks is degeneration of the retinal pigmented epithelium (RPE), which also is an FDA- accepted endpoint for registration clinical trials. GA remains an unmet medical need because, in large part, the mechanisms that promote RPE degeneration are not fully resolved. Earlier, we identified a specific accumulation of toxic non-coding Alu RNAs in the RPE of GA eyes that results from a deficiency in DICER1 (Nature 2011), which triggers RPE degeneration by activating the canonical caspase-1 inflammasome (Cell 2012). Recently, we elucidated the signaling symphony that orchestrates this cellular toxicity: disruption of DICER1:Alu RNA homeostatic regulation induces non-canonical inflammasome activation, a molecular cascade mediated by caspase-4/11 and a novel, non-lytic gasdermin D (GSDMD)- dependent activation of caspase-1 and secretion of IL-18 (Nature Medicine 2018). Enhanced levels of these molecules were also identified in human GA, marking it as the first non-infectious human disease associated with the non-canonical inflammasome. Combined with our exciting preliminary data that amyloid β, another trigger of RPE degeneration, also activates the non-canonical inflammasome, these findings suggest that the non-canonical inflammasome could be an integrator of multiple toxic signals that drive RPE degeneration in GA. Given that the inflammasome responds to myriad triggers of cellular distress, it could represent a critical checkpoint that triggers cell death, and therefore an attractive target for halting RPE degeneration. However, we still lack an integrated understanding of inflammasome activation in GA, and how it induces RPE degeneration. A rigorous definition of these mechanisms is crucial to enhancing our understanding of the molecular drivers of this hallmark of GA and to developing rational treatments. We will provide novel functional insights into how dysregulated non-canonical inflammasome activation contributes to RPE degeneration via the following thematically integrated yet independent Aims: (1) Create a spatial map of the non-canonical inflammasome pathway in human donor eyes; (2) Define the role of Gasdermin D (GSDMD) in non-canonical inflammasome activation; (3) Determine whether targeting the non-canonical inflammasome pathway ameliorates RPE degeneration in acute and chronic animal models. These studies will illuminate novel aspects of the molecular and biochemical bases of RPE degeneration, and help validate a molecular targeting strategy that could be translated into clinical trials. As such, this proposal is aligned with the 5-year goals of the NEI's Retinal Diseases Program strategic plan.