GAP-43 基因的转录后调控子αCP2在视神经损伤后修复中的作用和机制研究

Central nervous system (CNS) damages in human and other mammals often lead to persistent deficits,because mature axons are lack of abilities to self-repair and regenerate after injury. In contrast, the CNS of certain lower veterbrates such as Xenopus laevis remain robust regenerative abilities throughout their life. Therefore, the discovery of the key molecules for the successful regeneration in lower veterbrates,coupled with the comparitive studies of their homologs in mammals, will definitely provide important clues for researches and knowledge of CNS regeneration in mammals. In this study, using Xenopus laevis optic nerve crush as our working model,we focused on the post-transcriptonal regulation ofαCP2 on GAP-43 mRNA, a key determinant of regeneration, and, more important, the role ofαCP2 during successful regenration. We set to study following questions: 1) Characterizing the binding site of αCP2 on GAP-43 mRNA using RNase T1 selection method. 2). Studying the translational control of αCP2 on GAP-43 mRNA using in vitro translational system and polysomal profiling technique. 3). Investigating the role of αCP2 during successful optic axonal regeneration by down-regulating or up-regulating its expression in retinal ganglion cells after optic nerve crush. Meanwhile, using GAP-43 as a target, we will study the underlying mechanisms of αCP2 on regeneration. Our research on mechanisms of lower vertebrates CNS regeneration will therefore shed lights on the development of new strategies and medicines to promote functional recovery after adult brain injury in humans.

人类及其他哺乳动物中枢神经系统损伤后往往极难复原，主要原因在于其成熟的神经元缺乏有效的自我修复和再生的能力。而某些低等脊椎动物如爪蟾中枢神经系统却保持终身再生能力，因此对其再生过程中关键分子的研究，以及和哺乳类中同源分子的比较，无疑可为哺乳动物中枢神经再生的研究提供宝贵线索。本课题以爪蟾视神经损伤为模型，着重研究在轴突再生中关键因子αCP2起的重要作用及其对再生相关蛋白GAP-43的转录后调控机制。我们致力于解决以下问题：1）利用RNA酶T1选择技术寻找αCP2和GAP-43 mRNA的结合位点。2）利用体外翻译系统和核糖体图谱实验研究αCP2对GAP-43 mRNA的翻译调控。3) 分别通过在体抑制和诱导视网膜神经节细胞中αCP2的表达，研究其在视神经再生中的作用，并以GAP-43 mRNA为对象，探讨其作用机理。本研究将为人类中枢神经损伤后再生的基础研究和药物研发提供新的线索和方向。

人类及其他哺乳动物中枢神经系统(CNS)损伤后往往极难复原,而某些低等脊椎动物如爪蟾CNS却保持终身再生能力。在本课题中，我们首先以爪蟾视神经损伤为模型，利用体外翻译系统和核糖体图谱实验证明了αCP2对GAP-43 mRNA的翻译调控，并且通过在体抑制和诱导视网膜神经节细胞中αCP2的表达，发现过表达αCP2对视神经再生起抑制作用。在随后的研究中，利用第二代基因测序工具，我们检测了大鼠脊柱撞击损伤后脊髓内lncRNA表达的变化情况并且成功的筛选出一个表达显著下降的lncRNA (lncSCIR1)。lncSCIR1的下调可以促进胶质细胞的增殖和迁移，并且影响已知的脊髓损伤应答基因的表达。本课题从低等脊椎动物出发，以哺乳动物为终点，分别研究了RNA结合蛋白和lncRNA在中枢神经系统损伤后表达的改变和可能扮演的角色，不仅对转录后调控在神经再生领域的作用开辟了全新的研究领域，也为下一步相关的临床研究开发提供了全新的靶向性目标。