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: 10673084
• 负责人: Diana del Carmen Lozano
• 金额: $ 38.83万
• 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/10673084
• 关键词: Actins; Acute; 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; Link; LoxP-flanked allele; Mediating; Metabolic; Microfilaments; Modeling; Molecular; Morphology; Mus; Neurodegenerative Disorders; Neuroglia; Operative Surgical Procedures; Optic Disk; Optic Nerve; Patients; Persons; Physiologic Intraocular Pressure; RNA Interference; Rattus; Reaction; Rho-associated kinase; Risk Factors; Rodent; Rodent Model; Role; Site; Tamoxifen; Techniques; Testing; Therapeutic; Time; Tissues; Work; anterior chamber; axon injury; axonal degeneration; fasudil; genetic approach; genetic manipulation; glial activation; in vivo; innovation; insight; kinase inhibitor; light microscopy; modifiable risk; mouse model; neuroprotection; new therapeutic target; novel; novel strategies; novel therapeutic intervention; optic nerve disorder; pharmacologic; 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（ONH）是青光眼中轴突损伤的主要部位，神经退行性疾病 这是不可逆转的失明的主要原因，影响了全球7600万人。眼内升高 压力（IOP）是青光眼唯一可修改的危险因素，而降低IOP是唯一可用的策略 减慢视力丧失的进展。这是针对针对的新型治疗策略的迫切需求 ONH内的轴突损伤部位。为了开发针对青光眼的新型ONH靶向治疗方法，我们必须 确定导致ONH轴突损伤的早期细胞事件。星形胶质细胞（ONH内的本地神经胶质）提供 轴突的结构和代谢支持。在神经退行性疾病中，包括青光眼，星形胶质细胞 变得“反应性”并显示结构和分子变化。在包括我们在内的几种青光眼模型中， 明显的ONH星形胶质细胞肌动蛋白和中间细丝的细胞骨架反应性发生在之前 可观察到的轴突损伤。 IOP依赖性ONH星形胶质细胞反应性是神经保护性还是帮助驱动 疾病，或这些反应反应的调节是否改变了轴突升高IOP的脆弱性仍然存在 不清楚。使用急性IOP升高的啮齿动物模型，我们的初步数据证明了ONH星形胶质细胞 通过缩回基于肌动蛋白的细胞延伸并减少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细胞合成等电势，并依赖于肌动蛋白细胞骨架 用于本地化）。此外，我们表明肌动蛋白细胞骨架稳定（使用Rho激酶抑制剂 fasudil）显着降低了ANH星形胶质细胞细胞骨架和间隙连接反应性，并保护轴突 模型。最后，使用实验室中制定的体内外科手术策略，我们表明onh星形胶质细胞可以是 通过局部小分子递送到ONH进行调节。在此提案中，我们将确定ONH的作用 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 局部和全身递送细胞骨架的小分子调节剂。接下来，我们将检查 使用小分子和 在我们的啮齿动物模型中抑制connexin43的遗传策略。轴突和星形胶质细胞特异性 ONH组织的免疫荧光将用于确定轴突损伤和星形胶质细胞的程度 IOP升高后的不同时间点的ONH响应。在这项工作的过程中，我们将解决 ONH星形胶质细胞细胞骨架和间隙连接在IOP依赖性轴突变性中的作用，以及 它们作为轴突保护的新型策略的调制。该项目的最终长期目标是实现 轻型新的星形胶质细胞特异性治疗靶标可减少全球青光眼视力丧失的燃烧。