MOLECULAR MECHANISMS UNDERLYING OPTIC NERVE REGENERATION

描述（来自申请人摘要的逐字记录）： 这项研究计划旨在阐明神经系统的分子机制， 生长和再生。一般认为，大脑中的神经元和 哺乳动物的视网膜不能再生神经纤维，这是一个很大的问题。 这是治疗视网膜变性疾病和损伤的挑战。 最近的数据已经确定，视网膜神经节细胞（RGC）是视网膜神经细胞的一部分。 内在地调节它们延伸神经纤维的能力， 原癌基因Bcl-2是支持神经传导机制的关键调节因子， 伸长率Bcl-2的这种生长刺激活性似乎不是一个重要因素。 这是其众所周知的抗凋亡功能的结果。的中心问题 这是Bcl-2促进视网膜再生的机制， 神经纤维长期以来，人们已经认识到，神经分化影响 神经生长现在很明显，Bcl-2的过表达抑制了细胞凋亡。 分化信号的功能，p53介导的转录激活， 和神经元中终末分化标记物的表达。因此有 假设Bcl-2可能作为p53-p21 WAF 1通路的阻遏物起作用 抑制神经终末分化，从而维持 RGCs生长神经纤维。使用基因工程小鼠模型以及 新的视网膜顶盖共培养物，这项研究计划的目的是阐明 Bcl-2可通过其支持视神经再生的功能途径。 我们的目标是：（1）研究Bcl-2是否抑制了终末细胞凋亡， 通过确定RGC标志物的水平和时间来分化RGC， 野生型和Bcl-2视网膜中的分化相关蛋白表达 突变小鼠;（2）测试Bcl-2是否通过 抑制分化信号p53-p21 WAF 1通路。在这里， Bcl-2和p53之间的功能相互作用将通过比较 p53的转录活性、亚细胞定位和磷酸化 在野生型、Bcl-2突变体和Bcl-2/p53双突变体小鼠中;和（3） 确定Bcl-2是否作用于共同的细胞通路以支持神经 通过比较来自Bcl-x的RGC的能力， 和Bcl-2转基因小鼠存活和再生神经纤维。鉴于 Bcl-2在神经元存活和神经再生中的功能重要性， 这些研究将为发展 神经保护药物和许多疾病的治疗策略介导 细胞死亡和神经生长失调，包括青光眼和黄斑 退化

DESCRIPTION (Verbatim from applicant's abstract): The long-term objective of this research plan is to elucidate the molecular mechanisms underlying nerve growth and regeneration. It is generally believed that neurons in the brain and retina of mammals are unable to regenerate nerve fibers, which presents a great challenge for the treatment of retinal degenerative disorders and damage. Recent data have established that retinal ganglion cells (RGCs) are intrinsically regulated in their ability to extend nerve fibers, and that the proto-oncogene Bcl-2 is a key regulator supporting the mechanism for nerve elongation. This growth-stimulating activity of Bcl-2 does not seem to be a consequence of its well-known anti-apoptotic function. The central question here is the mechanisms by which Bcl-2 promotes the regeneration of retinal nerve fibers. It has long been recognized that neural differentiation impacts nerve growth. It is now evident that overexpression of Bcl-2 suppresses the function of a differentiation signal, p53-mediated transcriptional activation, and expression of terminal differentiation markers in neurons. Therefore, it is hypothesized that Bcl-2 may function as a repressor of the p53-p21WAF1 pathway inhibiting neural terminal differentiation and thus, maintaining the ability of RGCs to grow nerve fibers. Using genetically-engineered mouse models as well as novel retinotectal co-cultures, this research plan is aimed at elucidating functional pathway(s) through which Bcl-2 may support optic nerve regeneration. Our goals are: (1) to investigate whether Bcl-2 inhibits the terminal differentiation of RGCs by determining levels and timing of RGC markers and differentiation-related protein expression in retinas of wild type and Bcl-2 mutant mice; (2) to test whether Bcl-2 supports nerve regeneration via suppression of the differentiation signal, p53-p21WAF1 pathway. Here, functional interactions between Bcl-2 and p53 will be assessed by comparing transcriptional activity, subcellular localization, and phosphorylation of p53 in wild type, Bcl-2 mutant, and Bcl-2/p53 double mutant mice; and (3) to determine whether Bcl-2 acts on a common cellular pathway to support nerve regeneration and neuronal survival by comparing the ability of RGCs from Bcl-x, and Bcl-2 transgenic mice to survive and regenerate nerve fibers. Given the functional importance of Bcl-2 in neuronal survival and nerve regeneration, these studies should provide valuable information for the development of neuroprotective drugs and therapeutic strategies for numerous diseases mediated by dysregulated cell death and nerve growth, including glaucoma and macular degeneration.