Nrf2 signaling and oxidative stress in Age-related macular degeneration

描述（由申请人提供）：视网膜相关性黄斑变性（AMD）是美国获得性失明的主要原因。早期疾病患者的预防和治疗选择有限且无效。为了解决这一缺陷，该提案侧重于早期疾病的潜在机制。吸烟是与AMD最强的流行病学联系，但我们并不完全了解其在这种疾病的病理生理学中的作用。香烟烟雾是一种强有力的化学氧化剂，也是一种有效的补体激活诱导剂。这两个因素被认为是重要的AMD发展。AMD中的关键早期事件是视网膜色素上皮（RPE）的凋亡，部分地通过不充分中和的氧化应激。核因子-红细胞2相关因子2（Nrf 2）是一种碱性亮氨酸拉链氧化还原敏感性转录因子，通过与称为抗氧化反应元件的顺式作用增强子序列结合来调节抗氧化和细胞保护基因的诱导型表达。正常情况下，Nrf 2水平较低，但在氧化刺激下，Nrf 2从其细胞质抑制剂Keap 1释放后，其核积累增加，并激活其下游抗氧化酶的协调转录。Nrf 2信号传导减少见于衰老和疾病，导致适应性应激反应不足。有趣的是，Nrf 2活性的降低可以通过合成的齐墩果酸三萜衍生物来逆转，这代表了一类很有前途的新型细胞保护剂，可防止氧化损伤。在这个提议中，我们假设慢性吸烟诱导眼底持续氧化应激，并且随着AMD的发作，局部Nrf 2信号传导变得不足。最近，我们发现慢性香烟烟雾诱导小鼠RPE的氧化和超微结构损伤，并最终导致细胞凋亡。我们将利用这个系统，使用转基因小鼠来解决我们的假设，其目的如下：1）为了测试Nrf 2信号传导保护免受香烟烟雾诱导的氧化应激和眼底细胞凋亡的假设。2)研究Nrf 2信号对补体激活的调节决定香烟烟雾诱导的眼底损伤和凋亡的假设。3)确定Nrf 2的药理学激活剂是否保护眼底免受氧化损伤和补体激活。

DESCRIPTION (provided by applicant): Age-related macular degeneration (AMD) is the leading cause of acquired blindness in the United States. Patients with early disease suffer from limited and ineffective options for prevention and treatment. To address this shortcoming, this proposal focuses on the mechanisms underlying early disease. Cigarette smoking is the strongest epidemiological link with AMD, yet we do not fully understand its role in the pathophysiology of this disease. Cigarette smoke is a powerful chemical oxidant, and a potent inducer of complement activation. Both of these factors are thought to be important in AMD development. A key early event in AMD is apoptosis of the retinal pigmented epithelium (RPE), in part through inadequately neutralized oxidative stress. Nuclear factor- erythroid 2-related factor 2 (Nrf2), a basic leucine zipper redox-sensitive transcription factor, regulates the inducible expression of antioxidant and cytoprotective genes by binding to the cis-acting enhancer sequence known as the antioxidant response element. Normally, Nrf2 levels are low, but with an oxidative stimulus, nuclear accumulation of Nrf2 increases after it is released from its cytoplasmic inhibitor Keap1, and activates the coordinated transcription of its downstream antioxidant enzymes. Decreased Nrf2 signaling is seen in aging and disease, resulting in an inadequate adaptive stress response. Intriguingly, the decreased Nrf2 activity can be reversed by the synthetic triterpenoid derivatives of oleonolic acid, which represent a promising new class of agents for cytoprotection from oxidative injury. In this proposal, we hypothesize that chronic cigarette smoking induces persistent oxidative stress in the fundus, and that local Nrf2 signaling becomes inadequate with the onset of AMD. Recently, we showed that chronic cigarette smoke induces oxidative and ultrastructural damage, and eventually apoptosis to the RPE of mice. We will exploit this system using genetically modified mice to address our hypothesis with the following aims: 1) To test the hypothesis that Nrf2 signaling protects against cigarette smoke-induced oxidative stress and apoptosis in the fundus. 2) To investigate the hypothesis that regulation by Nrf2 signaling on complement activation determines the damage and apoptosis to the fundus that is induced by cigarette smoke. 3) To determine if a pharmacological activator of Nrf2 protects the fundus from oxidative damage and complement activation.