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

项目摘要 青光眼是导致失明的第二大原因，影响全球7960万人1。这种盲目导致了 视网膜神经节细胞（RGC）的损失，并且主要与慢性高眼压（OHT）有关。 由于我们对OHT与RGC损失之间的分子途径的理解存在差距，目前唯一的研究是 减缓青光眼进展的临床策略是降低眼内压（IOP）。这一战略具有重大意义。 局限性，因为它不能阻止疾病，并且有很高比例的无应答者2。 IOP升高的幅度不同，并以几种方式破坏RGC。高海拔（高于收缩期血 压力）引起这些神经元的急性和严重的缺血性损伤，在闭角型中更常见。 青光眼，而较低幅度的慢性IOP升高随着时间的推移缓慢影响他们。急性缺血性损伤是 类似于中风，激活压力敏感性钙通道，诱导氧化和ER应激，ATP 通过激活的Panx 1/Cx半通道释放，并阻碍轴突运输3。最近的研究 揭示了内源性炎性小体的激活和随后的GasderminD孔的形成 是缺血性OHT损伤模型中神经元功能障碍和焦萎性死亡的主要机制4，5。在 相比之下，亚缺血性低水平但慢性IOP升高的发作可引起青光眼， 有害的短期行为6.除了这两种方式，低于缺血水平的快速IOP升高“尖峰”， 显示在人和啮齿动物的眼睛中诱导RGC功能障碍和青光眼变性7，8。在 对于人来说，这种压力峰值可以由手术和药物以及诸如揉眼睛、玩耍等活动引起。 管乐器，低头锻炼，举重，经常摄入咖啡因，这些都是 与更高的青光眼风险有关2.然而，这种相对较低的振幅引起RGC损伤的机制可能与其对神经元的损伤有关。 但对快速和反复出现的峰值IOP波动知之甚少。 在这个项目中，我利用亚缺血OHT尖峰（SIOHS）模型来研究早期RGC损伤 途径及其在青光眼RGC变性中的作用。我主要关注的是 亚缺血OHT引起的急性应激伴随功能缺陷和RGC损失。在这个项目中，我将测试 眼压刺激下RGCs细胞表面机械敏感性通道过度激活假说 尖峰通过内源性炎性体的活性引发代谢应激和最终损失。 为了验证这一点，我将确定1。内源性神经炎症在RGC功能障碍和死亡中作用 在SIOHS之后，以及2.检测细胞表面TLRPV 4受体信号通路是否特异性响应于 SIOHS事件。

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.