Nrf2 signaling and oxidative stress in age-related macular degeneration

描述（由申请人提供）：老年性黄斑变性（AMD）是老年人失明的主要原因，但早期发病的患者没有得到治疗。为了解决这一缺点，本建议侧重于早期疾病。早期AMD的两个关键事件是视网膜色素上皮细胞（RPE）功能障碍和药物生物发生。不充分的活性氧（ROS）和失调的先天免疫相互作用，发挥关键作用。氧化稳态的核心，特别是在线粒体中，是Nrf2转录因子，它控制着最全面的抗氧化反应系统。Nrf2信号会随着年龄和/或吸烟而受损。本提案的目的是确定Nrf2如何保护RPE线粒体功能障碍和不调节的先天免疫。待验证的假设是，Nrf2信号受损会诱导线粒体和RPE功能障碍，从而导致氧化、炎症和病理微环境。建议的具体目标是：1。确定Nrf2信号受损导致未中和线粒体ROS和RPE功能障碍与香烟烟雾暴露的程度。我们的假设是，衰老和长期吸烟导致RPE中Nrf2信号受损，降低了线粒体抗氧化防御，导致ROS中和不足和RPE功能障碍。2. 确定Nrf2信号受损减少线粒体自噬的程度，并导致香烟烟雾暴露导致RPE功能障碍。我们的假设是，衰老和长期吸烟导致RPE中Nrf2信号受损，减少了线粒体自噬，累积增加了功能失调线粒体的数量和未充分中和的ROS，导致RPE功能障碍。3. 确定受损的Nrf2信号干扰先天免疫调节的程度。基于我们的研究表明CS和Nrf2缺乏会产生C3a和IL-1b，我们的假设是Nrf2信号受损会放大氧化应激，从而激活炎性小体，促进促炎微环境，并积聚功能受损的巨噬细胞。这些贡献意义重大，因为它们将确立Nrf2作为早期AMD的治疗靶点。这项研究具有创新性，因为它将使用独特的、最先进的遗传小鼠，研究未被研究的（线粒体抗氧化剂和线粒体自噬中Nrf2信号的减少）、未被研究的（炎性体和巨噬细胞功能）和独特的（ROS和先天免疫的协同作用）因素对RPE和巨噬细胞功能的影响，这些因素具有新鲜的、但具有决定性的、以前未被测试过的因素。巨噬细胞将从定义表型和功能的新角度进行研究，因为它们都受周围环境的影响。我们发现Nrf2减少与衰老和CS有关，CS产生C3a和IL-1b，这是炎症小体的关键底物，我们提出的研究将补体与炎症小体、巨噬细胞功能和AMD表型联系起来，这是非常具有创新性的。这项工作有望产生靶向治疗，重新激活Nrf2以维持氧化稳态和保护性先天免疫。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly, yet patients with early disease are without therapy. To address this shortcoming, this proposal focuses on early disease. Two key events in early AMD are retinal pigment epithelial cell (RPE) dysfunction and drusen biogenesis. Inadequately neutralized reactive oxygen species (ROS) and dysregulated innate immunity interact together to play a pivotal role. Central to oxidative homeostasis, especially in mitochondria, is the Nrf2 transcription factor, which controls the most comprehensive antioxidant response system. Nrf2 signaling can become impaired with aging and/or smoking. The objective of this proposal to define how Nrf2 protects against RPE mitochondrial dysfunction and unregulated innate immunity. The hypothesis to be tested is that that impaired Nrf2 signaling induces mitochondrial and RPE dysfunction that results in an oxidative, inflammatory, and pathologic microenvironment. The proposed specific aims are: 1. Determine the extent that impaired Nrf2 signaling leads to un-neutralized mitochondrial ROS and RPE dysfunction with cigarette smoke exposure. Our hypothesis is that impaired Nrf2 signaling in the RPE from aging and chronic smoking reduces mitochondrial antioxidant defense resulting in inadequately neutralized ROS and RPE dysfunction. 2. Determine the extent that impaired Nrf2 signaling decreases mitophagy, and results in RPE dysfunction with cigarette smoke exposure. Our hypothesis is that impaired Nrf2 signaling in the RPE from aging and chronic smoking decreases mitophagy, cumulatively increasing the number of dysfunctional mitochondria and inadequately neutralized ROS, resulting in RPE dysfunction. 3. Determine the extent that impaired Nrf2 signaling disrupts regulation of innate immunity. Based on our work showing C3a and IL-1b generation by CS and Nrf2 deficiency, our hypothesis is that impaired Nrf2 signaling magnifies oxidative stress, which activates the inflammasome to promote a pro-inflammatory microenvironment with accumulation of macrophages with impaired function. These contributions are significant because they will establish Nrf2 as a treatment target for early AMD. The research is innovative since it will investigate understudied (decreased Nrf2 signaling on mitochondrial antioxidants and mitophagy), unresolved (inflammasome and macrophage function) and unique (the synergy of ROS and innate immunity) factors on RPE and macrophage function using unique, state-of-the- art genetic mice with fresh, but decisive factors that have not been previously tested. Macrophages will be studied from a new perspective that defines both phenotype and function since both are influenced by their surroundings. Our discovery of reduced Nrf2 with aging and CS, which generates C3a and IL-1b, a key substrate of the inflammasome, and the proposed studies, which will link complement with the inflammasome, macrophage function, and an AMD phenotype, is highly innovative. Targeted therapy that reinvigorates Nrf2 to maintain oxidative homeostasis and protective innate immunity is expected to result from this work.