Targeting lysosome/RPE heterogeneity in AMD pathobiology as a novel therapy

摘要：年龄相关性黄斑变性（AMD）的视力丧失是一个主要的，不断扩大的问题， 人口老龄化虽然治疗可用于中期AMD和先进的湿形式，没有预防 或治疗可用于早期AMD。虽然细胞异质性可以帮助组织适应压力，但退行性变 衰老的异质性与疾病有关。目前的观点是RPE（视网膜色素沉着） 上皮）变性是不可避免地导致细胞死亡的中心慢性过程。因此，先前的研究 集中于RPE细胞死亡对AMD病理学的影响。然而，RPE细胞的一个子集表现出特征， 上皮-间充质转化（EMT）是一种适应性过程，允许细胞在恶劣的环境中生存。 RPE异质性已经被认识了一段时间，但疾病驱动细胞亚群对AMD的影响 发病机制尚未考虑。溶酶体功能障碍显然涉及几个年龄相关的 包括AMD在内的疾病，但溶酶体损伤的异质性的影响，这可能会导致疾病， RPE细胞功能或异质性尚未考虑。这个建议是背离常规的 因为它提出了RPE异质性，包括早期AMD中具有EMT的细胞亚群，是由 溶酶体清除缺陷的异质性。EMT中的RPE对死亡具有抵抗力，因此可能导致AMD 病理生物学在很长一段时间内。另一方面，由于EMT是可以逆转的，EMT中的RPE是一种可逆转的细胞。 引人注目的治疗目标，因为它的视力保护功能可以恢复。溶酶体功能和 自噬由主调节转录因子EB（TFEB）调节。本实验室 结果显示，与年龄匹配的AMD患者相比， 对照，从而将TFEB鉴定为AMD的潜在治疗靶标。考虑到异质性 由于溶酶体功能障碍导致RPE异质性，从EMT到变性，本提案的目的是 确定恢复溶酶体功能和自噬对AMD相关RPE的影响， 我们验证的溶酶体损伤Cryba 1 cKO啮齿动物模型中的异质性， 表型和人-iPSC衍生的RPE细胞中。“使溶酶体和细胞再生”的中心假设是， 通过激活TFEB的自噬功能将维持RPE细胞功能并防止病理性RPE异质性 包括EMT，在早期AMD”将解决以下目标：目标1：测试TFEB的程度， 激活使溶酶体/自噬功能恢复活力，并调节RPE异质性和RPE细胞健康。 目的2：测试Cryba 1 cKO小鼠RPE中TFEB激活挽救其AMD样表型的程度。 目的3：检测AMD中溶酶体异质性导致RPE异质性的程度。成功完成 这一建议的提出将建立溶酶体/自噬功能障碍作为RPE的关键驱动力的新概念 并鉴定TFEB作为新治疗剂。

SUMMARY: Vision loss from age-related macular degeneration (AMD) is a major, expanding problem due to the aging population. While treatment is available for intermediate AMD and the advanced wet form, no prevention or treatment is available for early AMD. While cellular heterogeneity can help tissue adapt to stress, degenerative heterogeneity from aging is associated with disease. The current perspective is that RPE (retinal pigmented epithelium) degeneration is a central, chronic process that inevitably leads to cell death. Thus, prior studies have focused on the impact of RPE cell death on AMD pathobiology. However, a subset of RPE cells exhibit features of epithelial-mesenchymal transition (EMT), an adaptive process that allows cells to survive a harsh environment. RPE heterogeneity has been recognized for some time, but the impact of disease driving cell subsets on AMD pathogenesis has not been considered. Lysosomal dysfunction is clearly involved in several age-related diseases including AMD, but the impact of heterogeneity of lysosomal impairment, which can cause disease, on RPE cellular function or heterogeneity has not been considered. This proposal is a departure from the norm because it proposes that RPE heterogeneity including a subset of cells with EMT in early AMD is initiated by heterogeneity of lysosomal clearance defects. RPE in EMT are resistant to death, and thus, could drive AMD pathobiology for an extended period. On the other hand, since EMT can be reversed, RPE in EMT are a compelling treatment target because its vision preserving functions can be restored. Lysosomal function and autophagy are modulated by the master regulator transcription factor EB (TFEB). Our laboratory has demonstrated reduced nuclear TFEB staining in the RPE of early AMD globes compared to age-matched controls, thus identifying TFEB as a potential therapeutic target for AMD. Given the possibility that heterogeneity of lysosomal dysfunction drives RPE heterogeneity, from EMT to degeneration, the objective of this proposal is to determine the impact of restoring lysosomal function and autophagy on the AMD-associated RPE heterogeneity in our validated Cryba1 cKO rodent model of lysosomal impairment that develops a dry AMD-like phenotype, and in human-iPSC derived RPE cells. The central hypothesis of “rejuvenating lysosomal and autophagic function by activating TFEB will maintain RPE cell function and prevent pathologic RPE heterogeneity including EMT, in early AMD” will be addressed with the following aims: Aim 1: Test the extent that TFEB activation rejuvenates lysosomal/autophagy function, and modulates RPE heterogeneity and RPE cell health. Aim 2: Test the degree that TFEB activation in the RPE of Cryba1 cKO mice rescues its AMD-like phenotype. Aim 3: Test the degree that lysosomal heterogeneity leads to RPE heterogeneity in AMD. Successful completion of this proposal will establish the novel concept of lysosome/autophagy dysfunction as a key driver of RPE heterogeneity in early AMD and identify TFEB as a novel therapeutic agent.