Role and regulation of inflammasome in the intraocular pressure-induced injury of retinal ganglion cells

项目总结 青光眼是导致失明的第二大原因，全世界有7960万人1。 与视网膜神经节细胞(RGC)的丧失有关，主要与慢性高眼压(OHT)有关。 由于我们对连接OHT和RGC损失的分子通路的理解存在差距，目前唯一的 降低眼压(IOP)是减缓青光眼进展的临床策略。这一战略严重影响了 限制，因为它不能阻止疾病，而且无应答者的比例很高。 眼压升高的程度各不相同，并以多种方式扰乱视网膜节细胞。高海拔(高于收缩压血 压力)导致这些神经元的急性和严重的缺血性损伤，闭角型更常见 青光眼，而较低幅度的慢性眼压升高随着时间的推移会慢慢影响他们。急性缺血性损伤是 类似于中风，激活压力敏感的钙通道，诱导氧化和内质网应激，ATP 通过激活的Panx1/Cx半通道释放，并阻碍轴突运输。最近的研究表明 揭示了内源性炎症小体的激活和随后GasderminD毛孔的形成 是缺血型OHT损伤模型4、5中神经元功能障碍和嗜酸性死亡的主要机制。 相比之下，亚缺血低水平但慢性眼压升高的发作可导致青光眼，尽管不是 有害的短期行为。除了这两种方式外，快速升高的眼压低于缺血水平还有 在人类和啮齿动物的眼睛中都被证明导致RGC功能障碍和青光眼退化7，8。 人，这样的压力峰值可能是由手术和药物以及诸如揉眼睛、玩耍等活动引起的 吹奏乐器、低头运动、举重和频繁摄入咖啡因，这些都是 与较高的青光眼风险有关。然而，这种相对较低的幅度导致RGC损伤的机制 但人们对快速且反复出现的眼压波动知之甚少。 在这个项目中，我利用一个亚缺血型OHT棘波模型(SIOHS)来研究RGC的早期损伤 青光眼视网膜节细胞变性的途径及其作用。我的主要关注点是将温和性 亚缺血型OHT的急性应激反应伴随着功能缺陷和RGC丢失。在这个项目中，我将测试 眼内压刺激视网膜神经节细胞表面机械敏感通道过度激活的假说 刺激物通过内源性炎性小体的活动启动新陈代谢应激和最终损失。 为了研究这一点，我将确定1.内源性神经炎在RGC功能障碍和死亡中的作用 SIOHS之后，以及2.检测细胞表面TLRPV4受体信号通路是否对 SIOHS活动。

PROJECT SUMMARY Glaucoma is the second leading cause of blindness, impacting 79.6 million worldwide 1. This blindness results from the loss of retinal ganglion cells (RGCs) and is primarily linked to chronic ocular hypertension (OHT). Because of gaps in our understanding of the molecular pathways linking OHT with RGC loss, the only current clinical strategy to slow glaucoma progression is to lower intraocular pressure (IOP). This strategy has serious limitations as it does not stop the disease and has a high proportion of non-responders 2. Elevation of IOP varies in magnitude and disrupts RGCs in several ways. High elevation (above systolic blood pressure) causes an acute and severe ischemic injury in these neurons, more common in closed-angle glaucoma, while lower magnitude chronic IOP elevations affect them slowly over time. Acute ischemic injury is similar to a stroke that activates pressure-sensitive calcium channels, induces oxidative and ER stresses, ATP release via activated Panx1/Cx hemichannels, and obstructs axonal transport3. More recent studies have revealed that the activation of the endogenous inflammasome and subsequent formation of GasderminD pores is a primary mechanism in neuronal dysfunction and pyroptotic death in ischemic OHT injury models 4, 5. In contrast, episodes of sub-ischemic low level but chronic IOP elevations can cause glaucoma despite being non- injurious short term6. In addition to these two modalities, rapid IOP elevation “spikes” below ischemic levels have been shown to induce RGC dysfunction and glaucomatous degeneration in both human and rodent eyes7, 8. In people, such pressure spikes can be induced by surgery and drugs and by activities such as eye rubbing, playing wind instruments, head down exercising, heavy weight lifting, and frequent caffeine intake, which have been linked to higher glaucoma risk2. However, the mechanisms causing RGC injury by such relatively low amplitude but rapid and recurring spiking IOP fluctuations are poorly understood. In this project, I utilize a model of sub-ischemic OHT spikes (SIOHS) to investigate early RGC-damaging pathways and their role in glaucomatous RGC degeneration. My main focus is on the mechanism linking mild acute stress by sub-ischemic OHT spikes with the functional deficit and RGC loss. In this project, I will test the hypothesis that overactivation of mechanosensitive channels on the cell surface of RGCs challenged by IOP spikes initiates metabolic stress and eventual loss via the activity of endogenous inflammasome. To examine this, I will determine 1. the role of endogenous neuroinflammation in RGC dysfunction and death following SIOHS, and 2. Test if cell surface TLRPV4 receptor signaling pathway is specifically responsive to SIOHS events.