Molecular Bases of Neuronal Connectivity

描述(申请人提供)：在正常情况下，成熟的视网膜神经节细胞(RGC)在视神经损伤后无法再生轴突，并很快开始死亡。然而，在之前的授权期中，研究表明，如果眼睛中的巨噬细胞被激活，许多RGC会在轴突切断后存活下来，并通过视神经抑制环境再生轴突。巨噬细胞中的一种蛋白质被发现可能介导了这些效应。目的1研究巨噬细胞衍生蛋白是否足以刺激体内视神经再生，确定该蛋白是否正常存在于发育中的视觉系统中，并鉴定其受体。目的2验证巨噬细胞衍生蛋白和某些辅助因子诱导轴突再生所需的不同分子变化的假设，并研究诱导的某些基因产物的功能意义。这项工作将利用之前的资助期间所做的研究，使用荧光激活的细胞分选来纯化视网膜节细胞，然后进行微阵列分析，以调查与成功的轴突再生相关的基因表达程序。Aim 3将测试这一假设，即在前一资金阶段分离的嘌呤敏感激酶是将生长因子刺激与轴突再生所需基因表达变化联系起来的信号转导途径的一部分。这项研究将大大增加我们对视神经再生的了解，并可能为青光眼和其他神经系统退行性或创伤性疾病的治疗干预提供新的靶点。

DESCRIPTION (provided by applicant): Under normal circumstances, mature retinal ganglion cells (RGCs) cannot regenerate their axons after optic nerve damage and soon begin to die. However, it was shown in the prior grant period that if macrophages become activated in the eye, many RGCs survive axotomy and regenerate their axons through the inhibitory environment of the optic nerve. A protein from macrophages was identified that may mediate these effects. Aim 1 will investigate whether this macrophage-derived protein is sufficient to stimulate optic nerve regeneration in vivo, determine whether this protein is normally present in the developing visual system, and identify its receptor. Aim 2 will test the hypothesis that the macrophage-derived protein and certain ancillary factors induce distinct molecular changes required for axon regeneration, and investigate the functional significance of some of the gene products that are induced. This work will capitalize on studies done in the prior grant period which used fluorescence-activated cell sorting to purify RGCs, followed by microarray analysis, to investigate the program of gene expression associated with successful axon regeneration. Aim 3 will test the hypothesis that a purine-sensitive kinase that was isolated in the prior funding period is part of a signal transduction pathway linking growth factor stimulation to the changes in gene expression required for axon regeneration. This research will add significantly to our understanding of optic nerve regeneration, and may provide novel targets for therapeutic interventions in glaucoma and other degenerative or traumatic disorders of the nervous system.