The Role of Pannexin1 in Ischemic Injury of Retinal Ganglion Cells

描述（由申请人提供）：我们的长期目标是预防视网膜缺血中的神经元损失和功能缺陷。 根据我们的目标，我们已经确定了一个新的，很少探索膜通道蛋白pannexin 1（Panx 1），作为一个有前途的来源，发现新的疗法。我们确定Panx 1作为缺血性神经元损伤的分子介导物发挥作用，基因消融该通道可保护视网膜神经节细胞免受缺血性神经元损伤。 缺血性损伤我们的中心假设指出，Panx 1作为一个关键的“收敛中心”的外部压力。我们提出的研究将比较Panx 1介导的不同毒性机制的相对贡献，并确定哪些刺激或其组合触发缺血时脆弱的视网膜神经节细胞中该通道的病理性开放。 具体目标旨在：1）分析由Panx 1通道开放触发的毒性途径，以确定它们对RGC损伤的相对贡献毒性。2）在实验性视网膜缺血-再灌注模型中，比较部分抑制与完全阻断或消融Panx 1通道在体内的保护作用。我们将重点关注缺血后神经元的存活和视网膜功能的保护。 意义保护视网膜神经元免受缺血性损伤， 这是一个全面的治疗策略。对Panx 1介导的毒性途径及其对神经元损伤的贡献的理解将永久改变视网膜和脑缺血的概念和治疗方法。我们将使用为该提案开发的专业知识和设计的独特工具来评估Panx 1阻断抑制或预防短暂性缺血中视力丧失的可行性，这是一个重要的临床问题和NIH NEI研究目标。 公共卫生相关性：我们的长期目标是预防视网膜缺血中的神经元丢失和功能缺陷。我们已经确定了一个新的，以前未开发的缺血性神经元损伤的分子介质，通道蛋白pannexin 1（Panx 1）。基于我们的主要发现表明Panx 1基因消融抑制缺血再灌注中的神经元损失，我们假设在缺血中Panx 1作为神经元损伤的分子介质起作用。我们的中心假设指出，Panx 1，通过打开一个大的膜孔，促进缺血性损伤和氧化应激的视网膜。我们试图揭示缺血时Panx 1与不同毒性通路激活之间的因果关系。我们已经开发了一种独特的Panx 1条件性基因敲除小鼠和新的Panx 1特异性膜片钳协议，以达到这一建议的目标。这项研究的主要成果包括对Panx 1介导的毒性途径及其对神经元损伤的贡献的新知识。我们还将测试Panx 1阻断剂在缓解视网膜缺血方面的治疗潜力。 使用缺血-再灌注动物模型的损伤。

DESCRIPTION (provided by applicant): Our long-term goal is to prevent neuronal loss and functional deficits in retinal ischemia. Pursuant to our objective, we have identified a new, scantily explored membrane channel protein pannexin1 (Panx1), as a promising source for discovering new therapies. We established that Panx1 function as a molecular mediator of ischemic neuronal injury, and genetic ablation of this channel protects retinal ganglion cells from ischemic damage. Our central hypothesis states that Panx1 serves as a critical "convergence hub" for external stressors. Our proposed studies will compare relative contribution of distinct toxicity mechanisms mediated by Panx1 and identify which stimuli or their combinations trigger pathological opening of this channel in vulnerable retinal ganglion cells in ischemia. Specific Aims are designed to: 1) analyze toxicity pathways triggered by the Panx1 channel opening for their relative contribution toxicity to RGC injury~ 2) Compare protective effects of partial inhibition vs. full blockade or ablation of Panx1 channel in vivo in experimental retinal ischemia-reperfusion model. We will focus on both neuronal survival and preservation of retinal functionality following ischemia. Significance. Protecting retinal neurons from ischemic injury is essential for a comprehensive therapeutic strategy. The understanding of the Panx1-mediated toxicity pathways and their contribution to neuronal injury will permanently alter both conceptual and therapeutic approaches to retinal and brain ischemia. We will use the expertise developed and the unique tools designed for this proposal to evaluate the feasibility of Panx1 blockade for suppressing or preventing the vision loss in transient ischemia, an important clinical problem and the NIH NEI research objective. PUBLIC HEALTH RELEVANCE: Our long-term goal is to prevent neuronal loss and functional deficits in retinal ischemia. We have identified a new, previously unexplored molecular mediator of ischemic neuronal injury, a channel protein pannexin1 (Panx1). Based on our main finding demonstrating that the Panx1 gene ablation suppresses neuronal loss in ischemia-reperfusion, we hypothesize that in ischemia Panx1 function as a molecular mediator of neuronal injury. Our central hypothesis states that Panx1, through opening of a large membrane pore, facilitates ischemic injury and oxidative stress to the retina. We seek to reveal cause-and-effect relationship between Panx1 and the activation of distinct toxicity pathways in ischemia. We have developed a unique Panx1 conditional knockout mouse and novel Panx1-specific patch clamp protocol to reach the objectives of this proposal. The major outcomes of this study include the new knowledge on the Panx1-mediated toxicity pathways and their contribution to neuronal injury. We will also test a therapeutic potential of Panx1 blockade in alleviating retinal ischemic injury using animal model of ischemia-reperfusion.