Deciphering the role of mitochondrial/autophagy dysfunction in regulating inflammatory processes during AMD pathogenesis

项目摘要：老年性黄斑变性(AMD)是导致老年人失明的主要原因 它是由多种遗传和环境因素驱动的，这些因素导致中央视力严重丧失。然而， 对于干性形式的疾病，目前还没有明确的治疗选择。炎症已经被认为是 在维持组织动态平衡方面起着重要作用。然而，放松管制的炎症反应是 与组织损伤和包括AMD在内的几种老年病的发病有关。即使有几个 研究已证实炎症在AMD发病机制中的作用，其潜在机制 控制炎性级联反应，特别是推动AMD慢性炎症的发生，仍然 仍然不为人知。我们最近报道了一项新的发现，在干性AMD患者9，10和一只小鼠身上 干性AMD模型视网膜色素中Akt2信号的激活引起炎症反应 视网膜色素上皮(RPE)细胞--干性AMD的第一批细胞。重要的是，Akt2在这个小鼠模型中的抑制 减轻视网膜炎症，减轻早期RPE改变。此外，AMD患者还患有 与对照组相比，黄斑RPE细胞中Akt2水平升高。因此，要评价Akt2的作用 在RPE健康和视网膜变性中的激活，我们已经产生了RPE特异性的Best1(Akt2)成分 敲入(Ki)小鼠。这些小鼠表现出干燥的AMD样表型，从基底板沉积中可以明显看出， RPE中Ezrin表达减少、色素沉着和形态改变，以及 视网膜功能下降。我们建议使用这个小鼠模型和来自CFH(Y/Y)的IPSC来源的RPE。 [对照]和CFH(H/H)[包含AMD风险等位基因]捐献者作为本研究中测试我们的 RPE中Akt2信号的激活触发线粒体/自噬功能障碍的假说 导致氧化应激和炎症，这是AMD早期发病的关键因素。至 针对这一假设，我们提出了以下目标：具体目标1(指导阶段)：测试我们的 假设Akt2在RPE中过表达导致线粒体/有丝分裂功能障碍，从而导致 氧化应激；特定目标2(指导阶段)：验证我们的假设，即RPE中Akt2的激活 驱动视网膜炎症；特定目标3(独立阶段)：测试我们的假设 与自噬介导的炎症调节相关的级联反应在AMD的发病机制中起着关键作用。 这项拟议的研究意义重大，因为我们将使用独特的、最先进的活体动物模型和 将我们的研究扩展到人类IPSC来源的RPE样本，以研究炎症如何影响视力 减少AMD的损失，并开发可能导致早期干燥性AMD的新治疗方式的策略。

Project Summary: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly and is driven by multiple genetic and environmental factors that lead to severe loss of central vision. However, no definitive treatment options are available for the dry form of the disease. Inflammation has been known to play an important role in maintaining tissue homeostasis. However, a deregulated inflammatory response is associated with tissue damage and the onset of several aging diseases, including AMD. Even though several studies have demonstrated the role of inflammation in AMD pathogenesis, the underlying mechanism controlling the inflammatory cascades, particularly driving the onset of chronic inflammation in AMD, still remains unknown. We have recently reported the novel finding that in dry AMD patients9,10 and in a mouse model of dry AMD, there is inflammation induction due to the activation of Akt2 signaling in the retinal pigment epithelial (RPE) cells-the first cells affected in dry AMD. Importantly, Akt2 inhibition in this mouse model reduced retinal inflammation and alleviated early RPE changes. Additionally, AMD patients also have increased Akt2 levels in the macular RPE cells relative to controls. Therefore, to evaluate the role of Akt2 activation in RPE health and in retinal degeneration, we have generated RPE-specific Best1 (Akt2) constitutive knock-in (KI) mice. These mice show a dry AMD-like phenotype, as evident from basal laminar deposits, decreased ezrin expression, hyperpigmentation, and morphological alterations in the RPE, as well as decreased retinal function. We propose to use this mouse model and iPSC-derived RPE from CFH(Y/Y) [controls] and CFH(H/H) [AMD risk allele containing] donors as novel tools in this study for testing our central hypothesis that “activation of Akt2 signaling in the RPE triggers mitochondrial/autophagy dysfunction leading to oxidative stress and inflammation, which are critical factors in early AMD pathogenesis”. To address this hypothesis, we propose the following aims: Specific Aim 1 (mentored phase): To test our hypothesis that Akt2 overexpression in the RPE elicits mitochondrial/mitophagy dysfunction thereby inducing oxidative stress; Specific Aim 2 (mentored phase): To test our hypothesis that activation of Akt2 in the RPE drives retinal inflammation; Specific Aim 3 (independent phase): To test our hypothesis that the molecular cascades associated with autophagy-mediated regulation of inflammation are critical in AMD pathogenesis. The proposed study is significant because we will use a unique, state-of-the-art in vivo animal model and extend our studies to human iPSC-derived RPE samples to investigate how inflammation contributes to vision loss in AMD and develop strategies potentially leading to a new treatment modality for early, dry AMD.