The Role of Pannexin 1 Pathway in Ocular Hypertension Injury of Retinal Ganglion Cells

摘要 高眼压是青光眼的主要危险因素，青光眼是一种影响8000万人的神经退行性疾病 全世界。视网膜神经节细胞及其轴突的丢失是青光眼的主要病理特征， 由机械损伤、神经炎症和危险信号引起的疾病。这些病理因素 在人类青光眼和实验动物模型中被发现。我们的长期目标是减少和， 最终，防止青光眼和其他由眼内引起的视网膜和视神经病变导致的视力丧失 压力。根据我们的目标，我们将描述一种促进RGC功能障碍和 通过P2X受体、pAnnexin1(Panx1)和视网膜中的炎症体之间的相互作用而丢失。我们的 该项目的前提是我们的初步研究确定了两个新的Panx1合作伙伴，这些合作伙伴可能有助于 RGC毒性，包括上游调控因子P2RX4和下游靶点炎症小体。我们发现 这一信号级联激活了核心的炎症体蛋白Caspase1和11。因此，我们将， 测试我们的中心假设，即神经元P2(R)X4的激活在Panx1介导的神经毒性中起关键作用， 这会在眼压升高时触发炎性小体激活。我们的三个具体目标 旨在验证这一假说，并确定视网膜炎症小体是否对RGC至关重要 功能障碍或丧失。 具体目的是：1)确定P2X4受体在Panx1介导的视网膜节细胞和视网膜节细胞丢失中的作用 2)研究P2(R)X4对Panx1、半胱氨酸天冬氨酸氨基转移酶和炎症小体的调节机制； 3)确定神经胶质细胞释放的ATP是否促进神经元炎性小体的激活并参与Panx1- 调解的RGC损失。 意义重大。该项目具有翻译潜力并具有重要意义，因为它正在开发和测试 对抗炎症诱导的神经变性的新策略，与青光眼有关，这是一个临床问题 被美国国立卫生研究院确定为一个重要的研究目标。预防主要致盲疾病的视力丧失，如 青光眼和其他视网膜缺血性损伤需要全面的、基于知识的治疗 策略。这一提议旨在为新发现的非 这些病理的动物模型中典型的炎症体途径。这项研究项目将建立 Panx1-P2X和炎症体通路靶向治疗在慢性眼病中的作用及可行性 高血压模型，与青光眼病理相关。如果成功，人类基础生物学的新知识 炎症诱导的视网膜神经元损伤将帮助我们为合理的药物设计寻找新的靶点。

Abstract Elevated IOP is the major risk factor in glaucoma, a neurodegenerative disorder affecting 80 million people worldwide. Loss of retinal ganglion cells and their axons is the major pathological hallmark of glaucoma, the disease facilitated by mechanical damage neuroinflammation and danger signaling. These pathological factors were identified in human glaucoma and in experimental animal models. Our long-term goal is to decrease and, ultimately, prevent vision loss in glaucoma and other retinal and optic nerve pathologies induced by intraocular pressure. Pursuant to our objective, we will characterize a novel pathway that facilitates RGC dysfunction and loss via an interaction between P2X receptors, pannexin1 (Panx1), and inflammasome in the retina. Our project is premised on our preliminary studies that identified two new Panx1 partners that may contribute to RGC toxicity, including upstream regulator P2RX4 and a downstream target, the inflammasome. We found that this signaling cascade activates caspase 1 and 11, the core inflammasome proteases. We will, therefore, test our central hypothesis that the activation of neuronal P2(R)X4 is pivotal for Panx1-mediated neurotoxicity, which triggers inflammasome activation in response to elevated intraocular pressure. Our three specific aims are designed to test this hypothesis and determine whether retinal inflammasome is critical for RGC dysfunction or loss. Specific Aims are designed to: 1) Establish the role of P2X4 receptor in Panx1-mediated loss of RGCs and their axons; 2) Examine the mechanism of P2(R)X4 regulation of Panx1, caspases and the inflammasome, and 3) Determine whether glial ATP release facilitate neuronal inflammasome activation and contribute to Panx1- mediated RGC loss. Significance. This project has a translational potential and is significant because it is developing and testing a novel strategy against inflammation-induced neurodegeneration, implicated in glaucoma, a clinical problem identified by the NIH as a crucial research objective. Preventing vision loss in major blinding pathologies like glaucoma and other ischemic injuries of retina require a comprehensive, knowledge-based therapeutic strategy. This proposal is designed to provide mechanistic understanding for the role of newly discovered non- canonical inflammasome pathway in animal models for these pathologies. This research project will establish the role and feasibility of therapeutic targeting of Panx1-P2X and inflammasome pathways in the chronic ocular hypertension models, relevant to glaucomatous pathology. If successful, the new knowledge of basic biology of inflammation-induced neuronal damage in the retina will help us to identify new targets for rational drug design.