Investigating the role of retinal astrocytes in exercise-induced retinal neuroprotection

研究视网膜星形胶质细胞在运动引起的视网膜神经保护中的作用

• 批准号: 10484539
• 负责人: Katie Leigh Bales
• 金额: --
• 依托单位: VETERANS HEALTH ADMINISTRATION
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10484539
• 关键词: Affect; Affinity; Age related macular degeneration; Animal Model; Astrocytes; Atrophic; Award; Biological Assay; Biology; Blindness; Blood Vessels; Brain; Brain-Derived Neurotrophic Factor; Cell Density; Cell Separation; Cells; Cellular Morphology; Clinical Research; Clinical Trials; Computer software; Data; Disease; Disease Progression; Endothelial Cells; Exercise; Exhibits; Foundations; Functional disorder; Future; Gene Expression; Goals; Healthcare; Hyperemia; Image; In Vitro; Inbred BALB C Mice; Inflammation; Intervention; Knowledge; Label; Light; Light Exercise; Magnetism; Mediating; Modeling; Modification; Molecular; Monitor; Morphology; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Plasticity; Neurotrophic Tyrosine Kinase Receptor Type 2; Outcome Study; Pathogenesis; Pathology; Patients; Persons; Phagocytosis; Pharmacology; Phenotype; Photoreceptors; Physiological; Process; Research; Retina; Retinal Degeneration; Retinitis Pigmentosa; Retrospective Studies; Role; Severities; Severity of illness; Signal Transduction; Stress; Structure; Testing; Therapeutic; Translating; Up-Regulation; Vascular Endothelial Cell; Veterans; Vision; Visual impairment; Writing; antagonist; base; cell type; density; exercise intervention; experimental group; gain of function; gene function; improved; improved functioning; military veteran; mouse model; neural repair; neuroinflammation; neuroprotection; neurovascular coupling; novel; patient population; preservation; receptor; relating to nervous system; repaired; response

Photoreceptor dysfunction is one of the hallmark pathologies associated with retinal degenerative (RD) diseases that manifests in patients as a progressive loss of vision. This encompasses heterogenous diseases such as retinitis pigmentosa, which affects 1 in 3500 people worldwide and age-related macular degeneration, which affects over 196 million people worldwide and is projected to reach 288 million people by 2040. Specifically, in our Veteran population, roughly 7,000 Veterans become visually impaired each year due to RD. Clinical trials and retrospective studies suggest that RD patients may respond to exercise as a neuroprotective treatment to preserve vision. Recently, our labs filled a significant knowledge gap by demonstrating that modest exercise protects retinal function and structure in models of RD and were accompanied by increased levels of brain derived neurotrophic factor (BDNF) and required intact BDNF-TrkB signal transduction. To date, the cell-types and molecular processes mediating the neuroprotective benefits of exercise are unknown. Others have shown that astrocytes and endothelial cells in the brain express BDNF and its high-affinity receptor, TrkB, and that altered BDNF-TrkB signaling in these cell-types contributes to neurodegenerative disease progression and severity. Recently, it has been demonstrated that astrocytes modify their morphology in response to BDNF in the brain during neurodegeneration. Likewise, vascular endothelial cells express BDNF under exercise-induced physiological stress. These data suggest that astrocytes and endothelial cells may mediate the neuroprotective effects of exercise in the retina. Our approach is to understand the morphological, gene expression and functional alterations in retinal astrocytes and vasculature induced from exercise and how these alterations contribute to neuroprotection. For this proposal, we will use the BALB/c light induced retinal degeneration model, which exhibits phenotypes found in patients with RD. We hypothesize that exercise induces retinal astrocyte plasticity and improved vascular function through increased BDNF signaling mechanisms, promoting neural repair and protection. In Specific Aim 1, we will investigate if exercise influences retinal astrocyte biology, by assessing retinal astrocyte morphology, cellular gene expression profiles, and retinal astrocyte-mediated phagocytosis. Immunohistochemical labeling, AnalyzeSkeleton and Sholl analysis will be used to quantify astrocyte cell morphology and density. Retinal astrocytes will be isolated using magnetic-activated cell sorting (MACS) to examine astrocyte gene expression profiles. To monitor retinal astrocyte function, a novel in vitro live-imaging of astrocyte-mediated phagocytosis will be used. In Specific Aim 2, we will determine the effects of exercise on retinal vascular morphology, gene expression and function. Angiotool will be used for retinal vascular morphology quantification analysis. Retinal vascular cell gene expression profiles will be assessed by MACS and vascular function will be assessed using retinal functional hyperemia. In Specific Aim 3, we will determine if exercise-induced BDNF signaling mechanisms influence retinal astrocyte and vascular morphology, gene expression and function, by blocking BDNF signaling using a highly specific TrkB receptor antagonist, ANA-12. Retinal astrocyte and vascular assessments performed in Specific Aims 1 and 2 found to be most informative will be used to compare experimental groups. The expected outcome of this study is that exercise-induced BDNF signaling alters retinal astrocyte and vascular morphology, gene expression and improves function in order to promote retinal neuroprotection. Results from this study will illuminate the morphological, gene expression and functional alterations that ultimately result in gain of function(s) and or loss/upregulation of homeostatic function(s) in retinal astrocytes and vasculature. This proposal holds profound potential for the long-term goals of optimizing exercise-based therapeutics and creating new pharmacological strategies targeting the underlying mechanisms of exercise-induced protection in patients with RD that can be extended to other neurodegenerative and neuroinflammatory diseases.

光感受器功能障碍是与视网膜变性 (RD) 相关的标志性病理学之一 患者表现为进行性视力丧失的疾病。这包括异质性疾病 例如，全球每 3500 人中就有 1 人患有色素性视网膜炎，以及与年龄相关的黄斑变性， 影响全球超过 1.96 亿人，预计到 2040 年将达到 2.88 亿人。 具体来说，在我们的退伍军人群体中，每年大约有 7,000 名退伍军人因 RD 而出现视力障碍。 临床试验和回顾性研究表明，RD 患者可能会对运动作为一种神经保护剂产生反应 治疗以保留视力。最近，我们的实验室通过证明以下内容填补了重大知识空白： 适度的运动可以保护 RD 模型中的视网膜功能和结构，并且伴随着视网膜功能和结构的增加 脑源性神经营养因子 (BDNF) 水平和所需的完整 BDNF-TrkB 信号转导。迄今为止， 介导运动的神经保护作用的细胞类型和分子过程尚不清楚。 其他研究表明，大脑中的星形胶质细胞和内皮细胞表达 BDNF 及其高亲和力 受体 TrkB 以及改变这些细胞类型中的 BDNF-TrkB 信号传导导致神经退行性疾病 疾病进展和严重程度。最近，已经证明星形胶质细胞改变了其形态 神经退行性变过程中大脑对 BDNF 的反应。同样，血管内皮细胞表达 BDNF 在运动引起的生理压力下。这些数据表明星形胶质细胞和内皮细胞可能 介导运动对视网膜的神经保护作用。我们的方法是了解形态学、 运动引起的视网膜星形胶质细胞和脉管系统的基因表达和功能改变以及如何改变 这些改变有助于神经保护。对于这个提案，我们将使用 BALB/c 光诱导视网膜 退化模型，表现出 RD 患者的表型。我们假设锻炼 通过增加 BDNF 信号传导诱导视网膜星形胶质细胞可塑性并改善血管功能 机制，促进神经修复和保护。在具体目标 1 中，我们将调查锻炼是否 通过评估视网膜星形胶质细胞形态、细胞基因表达来影响视网膜星形胶质细胞生物学 概况和视网膜星形胶质细胞介导的吞噬作用。免疫组织化学标记、分析骨骼和 Sholl 分析将用于量化星形胶质细胞形态和密度。将分离视网膜星形胶质细胞 使用磁激活细胞分选 (MACS) 来检查星形胶质细胞基因表达谱。监测视网膜 星形胶质细胞功能，将使用星形胶质细胞介导的吞噬作用的新型体外实时成像。具体来说 目标 2，我们将确定运动对视网膜血管形态、基因表达和功能的影响。 Angiotool将用于视网膜血管形态量化分析。视网膜血管细胞基因 表达谱将通过 MACS 进行评估，血管功能将使用视网膜功能评估 充血。在具体目标 3 中，我们将确定运动诱导的 BDNF 信号机制是否会影响 通过使用 BDNF 信号传导阻断视网膜星形胶质细胞和血管形态、基因表达和功能 高度特异性 TrkB 受体拮抗剂，ANA-12。视网膜星形胶质细胞和血管评估 信息最丰富的具体目标 1 和 2 将用于比较实验组。这 这项研究的预期结果是运动诱导的 BDNF 信号传导改变视网膜星形胶质细胞和血管 形态、基因表达和改善功能，以促进视网膜神经保护。结果来自 这项研究将阐明最终导致的形态、基因表达和功能改变 视网膜星形胶质细胞和脉管系统功能的获得和/或稳态功能的丧失/上调。 该提案对于优化基于运动的治疗和治疗的长期目标具有巨大的潜力。 针对运动引起的保护的潜在机制制定新的药理学策略 RD 患者的治疗可扩展到其他神经退行性疾病和神经炎症性疾病。