Cell Biology of Astrocyte-Ganglion Cell Interactions in the Retina and Optic Nerve

视网膜和视神经星形胶质细胞-神经节细胞相互作用的细胞生物学

• 批准号: 10356127
• 负责人: Tatjana Claudia Jakobs
• 金额: $ 41.97万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10356127
• 关键词: Address; Adverse effects; Affect; Age; Alpha Cell; Anatomy; Astrocytes; Axon; Axonal Transport; Cell Communication; Cell Survival; Cell physiology; Cells; Cellular biology; Chronic; Cytoprotection; Disease; Dyes; Electron Microscopy; Eye; Gene Expression; Gene Expression Profile; Genetic; Glaucoma; Grant; Health; Injections; Injury; Integrin Binding; Knockout Mice; Laboratories; Light; Measurement; Measures; Mediating; Microspheres; Modeling; Morphology; Mouse Strains; Mus; Nerve Crush; Neuroglia; Neurologic Signs; Neurons; Neuroprotective Agents; Optic Disk; Optic Nerve; Optic Nerve Injuries; Outcome; Pattern; Pharmaceutical Preparations; Physiologic Intraocular Pressure; Play; Population; Property; Proteins; RUNX1 gene; Resistance; Retina; Retinal Ganglion Cells; Risk; Rodent; Role; STAT3 gene; Sclera; Sialoglycoproteins; Site; Study models; Swelling; Testing; Therapeutic; Therapeutic Uses; Tissues; Tracer; Transgenic Mice; Transgenic Organisms; Virus; Vision; Visual; Visual Acuity; Work; axon injury; axonal degeneration; base; cell type; design; ganglion cell; histological studies; light microscopy; mouse model; neurotrophic factor; novel therapeutic intervention; osteopontin; overexpression; patch clamp; prevent; protein biomarkers; response; restoration; side effect; tool; transcription factor

Project Summary Glaucoma leads to a progressive loss of retinal ganglion cells by mechanisms that are not fully understood. At present, lowering the intraocular pressure (IOP) is the only treatment, and new therapeutic approaches that prevent ganglion cell degeneration in a manner independent of IOP would be welcome. There is evidence that the first signs of ganglion cell degeneration occur in the optic nerve head where the ganglion cell axons exit the globe through a hole in the sclera to form the optic nerve. In this region, the axons are unmyelinated and come into direct contact with astrocytes. Optic nerve astrocytes react to injury – such as an increase in IOP - with changes in their morphology and gene expression pattern. We showed that, at least in the early stages of the disease, astrocyte reactivity is a protective response and preventing it leads to a worse outcome for ganglion cells and visual function. This result suggests that astrocytes, or astrocyte-derived factors, can be harnessed for a neuroprotective glaucoma therapy that could be added to IOP-lowering drugs that are already in use. In our search for astrocyte-derived factors that mediate the protective response, we identified secreted phosphoprotein 1 (SPP1, also called osteopontin). This protein is expressed only at low levels in the normal optic nerve, but it is robustly up-regulated in all rodent glaucoma models studied so far. In addition, SPP1 is constitutively expressed in a sparse population of retinal ganglion cells. Using an SPP1 knock out mouse, we showed that SPP1 deficiency leads to morphological signs of astrocyte and axon damage in the optic nerve head even in the absence of elevated IOP. In the microbead occlusion model of glaucoma, SPP1 deficient mice lose more ganglion cells and have worse visual function than wild-type controls. Most importantly, virus- mediated overexpression of SPP1 in the retina is highly protective of ganglion cell function and prevents ganglion cell loss without affecting IOP. Based on these findings, we believe that SPP1 may be a promising candidate for a neuroprotective therapy in glaucoma. However, at present we do not know whether the SPP1 expression in reactive astrocytes or in retinal ganglion cells or both are needed to achieve optimal protection. To address this question, we have designed a transgenic mouse strain that will allow for cell-type specific deletion of SPP1 in astrocytes, retinal ganglion cells (or other cell types) separately. The mice will also express different fluorescent marker proteins in targeted cells before and after the deletion of SPP1. We will use this new tool to address our hypothesis that astrocyte-derived SPP1 in the optic nerve and ganglion cell-derived SPP1 in the retina are both necessary for optimal ganglion cell protection in glaucoma (Aims 1 and 2). In our translational Aim 3, we will test whether overexpression of SPP1 is protective of retinal ganglion cell function in the long term and assess ocular tissues for adverse effects that may result from chronic SPP1 overexpression.

项目摘要 青光眼导致视网膜神经节细胞的进行性丢失，其机制尚不完全清楚。在… 目前，降低眼压(IOP)是唯一的治疗方法，而新的治疗方法 以一种独立于眼压的方式防止神经节细胞变性将是受欢迎的。有证据表明 神经节细胞变性的最初迹象出现在视神经头，神经节细胞轴突从视神经节细胞轴突离开视神经节细胞轴突的视神经头。 眼球通过巩膜上的一个洞形成视神经。在这个区域，轴突是无髓鞘的， 与星形胶质细胞直接接触。视神经星形胶质细胞对损伤--如眼压升高--的反应 它们的形态和基因表达模式的变化。我们证明了这一点，至少在 疾病，星形胶质细胞的反应是一种保护性反应，预防它会导致神经节细胞更糟糕的结果 细胞和视觉功能。这一结果表明，星形胶质细胞或星形胶质细胞衍生因子是可以利用的。 用于神经保护性青光眼治疗，这可能会添加到已经在使用的降眼压药物中。 在我们寻找介导保护性反应的星形胶质细胞衍生因子的过程中，我们发现分泌的 磷酸蛋白1(SPP1，又称骨桥蛋白)。这种蛋白只有在正常情况下低水平表达。 视神经，但到目前为止，在所有研究的啮齿动物青光眼模型中，它都显著上调。此外，SPP1是 在数量稀少的视网膜神经节细胞中呈结构性表达。使用SPP1基因敲除小鼠，我们 结果表明，SPP1缺乏导致视神经星形胶质细胞和轴突损伤的形态特征 即使在没有高眼压的情况下也是如此。在青光眼微珠阻塞模型中，SPP1缺失 与野生型对照组相比，小鼠失去了更多的神经节细胞，视觉功能更差。最重要的是，病毒- 介导的SPP1在视网膜中的过表达对神经节细胞功能具有高度的保护作用，并防止 神经节细胞丢失，不影响眼压。 基于这些发现，我们认为SPP1可能是一种有前途的神经保护疗法。 青光眼。然而，目前尚不清楚SPP1在反应性星形胶质细胞或星形胶质细胞中的表达。 需要视网膜神经节细胞或两者兼而有之才能获得最佳保护。为了解决这个问题，我们有 设计了一种转基因小鼠品系，将允许星形胶质细胞、视网膜细胞中SPP1的细胞类型特异性缺失 神经节细胞(或其他细胞类型)分开。小鼠也会表达不同的荧光标记蛋白。 在SPP1缺失前后的靶细胞中。我们将使用这个新工具来解决我们的假设 视神经中的星形胶质细胞来源的SPP1和视网膜中的神经节细胞来源的SPP1都是 青光眼的最佳神经节细胞保护(目标1和2)。在我们的翻译目标3中，我们将测试 SPP1过表达对视网膜神经节细胞功能的长期保护作用及对眼组织的评估 用于慢性SPP1过度表达可能导致的不良反应。