Autophagy: A critical factor in RPE aging and AMD

描述（由申请人提供）：年龄相关性黄斑变性（AMD）是美国老年人视力损害的主要原因。自噬是细胞内护的重要途径，在受损细胞器转运到溶酶体降解中起着关键作用。我们的数据证实，自噬在RPE管理中起着关键作用，自噬效率随年龄和AMD而下降。我们的结论是，当受损细胞器没有被清除和修复时，缺陷性自噬会损害正常的RPE功能。因此，我们假设RPE中自噬减少在视网膜老化和年龄相关性黄斑变性（AMD）的发病机制中起主要作用。我们进一步假设，通过降低自噬活性和等待自噬降解和替代的受损细胞内细胞器的积累，自噬减少有助于脂褐素的产生。我们相信，刺激自噬途径，进而减少累积的受损细胞器，将减少视网膜老化变化，减缓AMD的进展，并导致新的药理靶点的发现。”在目标1中，我们将描述人类和动物RPE中自噬途径的时空动态，并确定其如何随着年龄和AMD的进展而变化。在目标2中，我们将使用原代人RPE培养物来a)表征氧化损伤对自噬途径效率的作用及其处理日益增加的受损胞内细胞器负担的能力，b) RPE对氧化应激的易感性，以及c)评估自噬去除受损胞内细胞器对RPE中脂褐素形成的贡献。在目标3中，我们将评估修改自噬对体外和体内视网膜衰老和AMD模型的影响。我们将在体外确定那些最能抑制自噬并产生amd样病变的条件，并将其转化为动物，并确定下调自噬途径特定元件的表达水平或功能是否能诱导野生型小鼠的amd样病变。最后，我们将在两种小鼠模型中确定增强自噬途径是否可以减缓AMD的进展。我们相信，对AMD视网膜RPE自噬通路功能障碍的表征将为该疾病的治疗找到新的靶点。公共卫生相关性：老年性黄斑变性（AMD）是老年人失明的主要原因，在美国有超过1000万人因AMD而视力下降。了解自噬的作用将为AMD的发病机制提供新的信息，并可能有助于制定可持续的治疗策略，特别是对于干性AMD，这是NEI的优先领域。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the leading cause of visual impairment of the elderly in the US. Autophagy is a vital pathway in cellular housekeeping and plays a critical role in the translocation of damaged organelles to the lysosome for degradation. Our data confirm that autophagy plays a critical role in RPE housekeeping and that autophagic efficiency declines with both age and AMD. We conclude that defective autophagy will impair normal RPE function when removal and repair of damaged organelles does not occur. We therefore hypothesize that "Decreased autophagy in the RPE plays a major role in retinal aging and the pathogenesis of age-related macular degeneration (AMD). We further postulate that decreased autophagy contributes toward the genesis of lipofuscin, via a combination of reduced autophagic activity and an accumulation of damaged intracellular organelles awaiting autophagic degradation and replacement. We believe that stimulation of the autophagic pathway, which would in turn lead to a reduction in accumulated damaged organelles will reduce retinal aging changes and slow the progression of AMD and lead to the identification of new pharmacological targets." In aim 1, we will characterize the spatial and temporal dynamics of the autophagic pathway in human and animal RPE and determine how this changes with aging and the progression of AMD. In aim 2, we will use primary human RPE cultures to a) characterize the role of oxidative damage on the efficiency of the autophagic pathway and its ability to deal with an increasing burden of damaged intracellular organelles, b) the susceptibility of the RPE to oxidative stress following up or down regulation of the autophagic pathway and c) assess the contribution of autophagic removal of compromised intracellular organelles to lipofuscin formation in the RPE. In aim 3, we will assess the effect of modifying autophagy on in vitro and in vivo models of retinal aging and AMD. We will identify those conditions that best suppress autophagy and generate AMD-like lesions in vitro and translate these to animals and determine if down regulation of expression levels or function of specific elements of the autophagic pathways can induce the AMD-like lesions in wild type mice. Finally, we will determine if enhancing the autophagic pathway can slow the progression of AMD in two mouse models. We believe that characterization of dysfunction in the autophagic pathway in the RPE of AMD retinas will identify new targets in the treatment of this disease. PUBLIC HEALTH RELEVANCE: Age-related macular degeneration (AMD) is the major cause of blindness in the elderly, with over 10 million people having reduced vision due to AMD in the US. Understanding the role of autophagy will provide new information on the pathogenesis of AMD and may help develop a sustainable treatment strategy, especially for dry AMD, which is a priority area for the NEI.