Repair and Regeneration of Central Visual Pathways

描述（由申请人提供）：我们建议研究为什么中央视觉通路在损伤后不能再生，以及如何增强其修复。具体来说，我们将调查为什么成熟的视网膜神经节细胞（RGC）轴突不能再生轴突切断后。通过视神经的RGCs再生长期以来一直作为研究CNS再生失败的简单模型系统。大鼠视神经主要由RGC轴突、星形胶质细胞和髓鞘化少突胶质细胞组成。我们已经建立了纯化和培养啮齿类RGCs、视神经星形胶质细胞和少突胶质细胞的方法。使用这些方法，我们将继续研究促进和抑制RGC轴突在培养中伸长的分子机制，以及我们如何应用这些知识来增强再生。 在这个建议中，我们将调查的3个现象牵连的RGC轴突再生失败的分子基础。在上一个资助期，我们发现新生RGCs被无长突细胞发出信号，不可逆地失去了快速再生轴突的内在能力。在第一个目标中，我们将使用基因分析来研究这种损失的分子基础。在第二个目标中，我们研究了髓鞘相关的抑制剂再生的视神经和RGC受体，他们通过构建噬菌体展示库的单链抗体和选择抗体，增强RGC再生的结合的身份。在第三个上午，我们将探讨为什么清除髓鞘碎片在沃勒变性是如此延长视神经损伤后。我们将专门测试的假设，这是占最近发现，中枢神经系统小胶质细胞是不成熟的骨髓前体细胞，而不是静止的吞噬细胞。最后，我们将应用我们在前3个目的中所学到的知识，以确定我们是否可以在体内增强视神经损伤后的RGC再生。 我们的最终目标是了解为什么RGC不能再生远轴突切断，并开发新的治疗方法，促进其再生后，在眼部疾病，包括青光眼，视网膜缺血，视神经炎和神经病变损伤。

DESCRIPTION (provided by applicant): We propose to investigate why central visual pathways fail to regenerate after injury and how their repair can be enhanced. Specifically, we will investigate why the axons of mature retinal ganglion cells (RGCs) fail to regenerate after axotomy. The regeneration of RGCs through the optic nerve has long served as a simple model system for study of CNS regenerative failure. The rat optic nerve consists primarily of RGC axons, astrocytes, and myelinating oligodendrocytes. We have developed methods to purity and culture rodent RGCs, optic nerve astrocytes and oligodendrocytes. Using these methods we will continue to investigate the molecular mechanisms that promote and inhibit RGC axon elongation in culture, and how we can apply this knowledge to enhance regeneration. In this proposal, we will investigate the molecular basis of 3 phenomena implicated in the failure of RGC axons to regenerate. Over the last grant period, we discovered that neonatal RGCs are signaled by amacrine cells to irreversibly lose their intrinsic competence to rapidly regenerate their axons. In the first aim, we will use gene profiling to investigate the molecular basis for this loss. In the second aim, we investigate the identity of myelin-associated inhibitors of regeneration in the optic nerve and the RGC receptors that they bind to by constructing bacteriophage display libraries of single chain antibodies and selecting antibodies that enhance RGC regeneration. In the third am, we will investigate why the clearance of myelin debris in Wallerian degeneration is so prolonged after optic nerve injury. We will specifically test the hypothesis that this is accounted for by the recent discovery that CNS microglia are immature myeloid precursor cells rather than quiescent phagocytes. Finally, we will apply what we learn in the first 3 aims to determine if we can enhance RGC regeneration after optic nerve injury in vivo. Our ultimate goal is to understand why RGCs fail to regenerate afar axotomy and to develop new treatments promote their regeneration after injury in ocular diseases including glaucoma, retinal ischemia, optic neuritis, and neuropathy.