AMPK/SIRT1/PGC-1α, a critical pathway in dry AMD

摘要： 好了！ 年龄相关性黄斑变性(AMD)是导致55岁以上人群失明的主要原因。 美国和发达国家。AMD有两种形式，其中一种是“干性”形式，目前还没有 有效的治疗方法。因此，开发新的治疗方法有一个未得到满足的医学需求。 AMD。包括AMD在内的许多视网膜疾病都与线粒体功能障碍有关。 线粒体功能障碍会导致活性氧(ROS)水平升高，并导致代谢缺陷 活动。自噬缺失也会导致线粒体功能障碍，并被认为增加了对 氧化应激和AMD。我们最近显示出功能失调的自噬，ROS增加，以及 AMD供眼RPE中的线粒体功能障碍。然而，潜在的机制 诱导这些有缺陷的代谢同源同源酶导致AMD的机制尚不清楚。 过氧化物酶体增殖物激活受体-γ共激活因子-1α(pGC-1α)在体内发挥重要作用 在线粒体生物发生和氧化代谢中起主要作用。它还调节自噬和有丝分裂吞噬。 PGC-1的α活性受两个主要因素的刺激：AMP激活的蛋白激酶和NAD-1。 依赖脱乙酰酶，SIRT1。我们实验室的初步证据表明，AMPK/SIRT- 1/pgc-1α在AMD RPE中下调。根据我们的初步数据，我们假设 视网膜色素上皮抑制的AMPK/SIRT1/PGC-1α通路导致线粒体、自噬功能障碍和 ROS生成增加，导致代谢活动异常，脂肪和糖原积累，以及 黄褐斑的形成，导致了AMD的病理生理学。为了检验我们的假设，我们开发了一个 从AMD供者眼分离天然RPE建立取之不竭的AMD体外疾病模型 IPSC的产生及随后分化为RPE(AMD RPE-IPSC-RPE)。我们还有 从年龄匹配的正常供者(正常RPE-IPSC-RPE)的RPE中产生IPSC作为对照。我们 证实AMD RPE-IPSC-RPE模拟其父母供者的疾病表型，初级 AMD RPE，这验证了我们的模型。此外，我们建立了一个动物模型来测试pGC-1α的作用 抑制RPE和视网膜健康，并观察到RPE和光感受器退化。我们建议两个 目的：AIM1将利用我们建立的模型来测试AMPK/sirt-1/pgc-1α通路抑制在干性老年性痴呆中的作用。 AMD供者和AMD患者的体外模型。AIM2将研究细胞和分子机制 研究pgc-1α对小鼠视网膜色素上皮和视网膜健康的作用。最终，这些研究将提供洞察力 研究干性AMD的分子机制，并可能促进新的治疗干预措施的开发。

ABSTRACT: ! Age-related macular degeneration (AMD) is the major cause of blindness in people over age 55 in the U.S. and the developed world. One of the two forms of AMD is the “dry” form for which currently there are no effective treatments. Consequently, there is an unmet medical need for development of new therapies for AMD. A number of retinal diseases including AMD are associated with mitochondrial dysfunction5. Dysfunctional mitochondria induce increased levels of reactive oxygen species (ROS), and defective metabolic activity. Autophagy loss also results in mitochondrial dysfunction and is suggested to increase susceptibility to oxidative stress and AMD. We have recently shown dysfunctional autophagy, increased ROS, and dysfunctional mitochondria in RPE derived from AMD donor eyes. However, the underlying mechanisms inducing these defective metabolic homeostases leading to AMD remain unknown. The Peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha (PGC-1α) plays a major role in mitochondrial biogenesis and oxidative metabolism. It also regulates autophagy and mitophagy. PGC-1α activity is stimulated by two main factors: AMP-activated protein kinase (AMPK) and NAD+- dependent deacetylase, SIRT1. Preliminary evidence from our laboratory suggests that the AMPK/SIRT- 1/PGC-1α is down regulated in AMD RPE. Based on our preliminary data, we hypothesize that the repressed AMPK/SIRT1/PGC-1α pathway in RPE induces mitochondrial, autophagic dysfunction, and increased ROS production, which result in abnormal metabolic activity, lipid and glycogen accumulation, and drusen formation, leading to the AMD pathophysiology. To test our hypothesis, we have developed an inexhaustible AMD in vitro disease model by isolating native RPE from AMD donors' eyes followed by generation of iPSC, and their subsequent differentiation into RPE (AMD RPE-iPSC-RPE). We have also generated iPSC from RPE of age-matched normal donors (Normal RPE-iPSC-RPE) that serve as control. We confirmed that the AMD RPE-iPSC-RPE mimic the disease phenotypes of their parental donors, the primary AMD RPE, which validates our model. Additionally, we established an animal model to test the role of PGC-1α repression on RPE and retinal health and observed RPE and photoreceptor degeneration. We propose two aims: Aim1 will test the role of AMPK/SIRT-1/PGC-1α pathway inhibition in dry AMD using our established in vitro model from AMD donors and AMD patients. Aim2 will investigate the cellular and molecular mechanisms of PGC-1α actions on RPE and retinal health in a mouse model. Ultimately, these studies will provide insight into the molecular mechanisms of dry AMD and may facilitate development of new therapeutic interventions.