Modulation of optic nerve head astrocyte reactivity in glaucoma

青光眼视神经乳头星形胶质细胞反应性的调节

• 批准号: 10222704
• 负责人: Shandiz Tehrani
• 金额: $ 37.67万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10222704
• 关键词: Actins; Acute; Address; Adult Children; Affect; Animals; Astrocytes; Attenuated; Axon; Biological; Blindness; Cannulations; Communication; Connexin 43; Connexins; Cytoskeletal Proteins; Cytoskeleton; Data; Development; Disease; Event; Future; Gap Junctions; Genes; Glaucoma; Glial Fibrillary Acidic Protein; Goals; Hour; Human; Immunofluorescence Immunologic; Immunofluorescence Microscopy; Intermediate Filaments; Knock-out; Knockout Mice; LIM Domain Kinase 1; Label; Lead; Link; LoxP-flanked allele; Mediating; Metabolic; Microfilaments; Modeling; Molecular; Morphology; Mus; Neurodegenerative Disorders; Neuroglia; Operative Surgical Procedures; Optic Disk; Optic Nerve; Patients; Pharmacology; Physiologic Intraocular Pressure; RNA Interference; Rattus; Rho-associated kinase; Risk Factors; Rodent; Rodent Model; Role; Site; Structure; Tamoxifen; Techniques; Testing; Therapeutic; Time; Tissues; Work; anterior chamber; axon injury; axonal degeneration; base; fasudil; genetic approach; genetic manipulation; in vivo; innovation; insight; kinase inhibitor; light microscopy; modifiable risk; mouse model; new therapeutic target; novel; novel strategies; novel therapeutic intervention; optic nerve disorder; prevent; response; small molecule; small molecule inhibitor; therapeutic target; tool; treatment strategy

Project Summary The optic nerve head (ONH) is the primary site of axon injury in glaucoma, a neurodegenerative disease that is the leading cause of irreversible blindness affecting 76 million people worldwide. Elevated intraocular pressure (IOP) is the only modifiable risk factor for glaucoma, and lowering IOP is the only available strategy to slow the progression of vision loss. Thus, there is a critical need for novel therapeutic strategies targeting the site of axon injury within the ONH. In order to develop novel ONH-targeted treatments for glaucoma, we must determine the early cellular events that lead to ONH axon injury. Astrocytes (local glia within the ONH) provide structural and metabolic support for axons. In neurodegenerative disorders including glaucoma, astrocytes become “reactive” and display structural and molecular changes. In several glaucoma models, including ours, significant ONH astrocyte actin- and intermediate filament-based cytoskeletal reactivity occurs prior to observable axon injury. Whether IOP-dependent ONH astrocyte reactivity is neuroprotective or helping drive disease, or whether modulation of these reactive responses alters axon vulnerability to elevated IOP remain unclear. Using a rodent model of acute IOP elevation, our preliminary data demonstrate that ONH astrocytes react by retracting their actin-based cellular extensions and reducing connexin43 labeling (an astrocyte gap junction protein involved in maintaining astrocyte syncytial isopotentiality, and reliant on the actin cytoskeleton for localization). Furthermore, we show that actin cytoskeletal stabilization (using the Rho kinase inhibitor fasudil) significantly reduces ONH astrocyte cytoskeletal & gap junction reactivity and protects axons in this model. Lastly, using an in vivo surgical strategy developed in our lab, we show that ONH astrocytes can be modulated by local small molecule delivery to the ONH. In this proposal, we will determine the role of ONH astrocyte cytoskeletal reactivity in axon degeneration after acute IOP elevation, by combining our rodent model with local and systemic delivery of small molecule modulators of the cytoskeleton. Next, we will examine the mechanistic role of ONH astrocytic connexin43 in IOP-dependent axon degeneration using small molecule and genetic strategies to suppress connexin43 in our rodent models. Axon- and astrocyte-specific immunofluorescence of ONH tissue will be used to determine the extent of axon injury and astrocyte responses within the ONH at various time points after IOP elevation. In the course of this work, we will address the role of the ONH astrocyte cytoskeleton and gap junctions in IOP-dependent axon degeneration, as well as their modulation as a novel strategy for axon protection. The ultimate long-term goal of this project is to bring to light new astrocyte-specific therapeutic targets to reduce the burden of glaucomatous vision loss worldwide.

项目摘要 视神经头（ON）是青光眼中轴突损伤的主要部位，神经退行性疾病 这是不可逆的失明的主要原因，影响了全世界的7600万个窥视 压力（IOP）是青光眼的唯一修改因素，而降低IOP也是唯一的可用策略 减慢视力损失的进展。 轴突损伤的位置，以发展新颖的青光眼靶向治疗 确定导致轴突损伤的早期细胞事件（ONH中的局部胶质细胞） 轴突的结构和代谢支持。 变成“反应性”，并显示结构和分子变化。 对星形胶质细胞肌动蛋白和基于国际细丝的细胞骨架反应的重要性也很重要 可观察的轴突损伤。 疾病，或反应反应的调节是否改变了轴突易受升高IOP的脆弱性。 我们的初步数据不清楚。 通过缩回基于拖拉蛋白的地窖延伸并降低connexin43标记来反应（星形胶质细胞间隙 连接蛋白涉及维持星形胶质同步等异位，并依赖于肌动蛋白细胞骨架 对于本地化）。 Fasudil）显着降低了星形胶质细胞细胞骨架和间隙连接反应性，并保护轴突 最后，使用我们实验室中开发的体内外科手术策略 通过局部小分子向ON进行调节。 急性IOP升高后轴突变性中的星形胶质细胞细胞骨架反应性，通过结合啮齿动物模型 与细胞骨架的局部和全身递送。 使用小分子和小分子在IOP依赖性轴突变性中，在星形胶质细胞连接的机械作用 在我们的啮齿动物模型中抑制connexin43的遗传策略。 在组织上的免疫荧光将用于确定轴突损伤的程度和星形胶质细胞的程度 在IOP高程之后的各个时间点内的响应。 依赖IOP依赖性轴突变性的星形胶质细胞骨架和间隙连接的作用， 它们作为轴突保护的新型策略。 轻型新的星形胶质细胞特异性治疗剂可减轻全球青光眼垂直损失的负担。