RhoA调控施万细胞微管动态及其在髓鞘化过程的作用与机制研究

Existing literatures indicate that RhoA mainly plays roles on regulating the microfilament dynamics via ROCK signaling pathway. Neural injury derived RhoA over-expression and activation is one of the core causes of growth cone collapse and nerve regeneration failures. Inhibition of RhoA signal can promote nerve repair. However, our previous study reveals inhibition of RhoA results in hindering the Schwann cell (SC) myelination, and this role is not via ROCK. Since cytoskeletal remodeling is a prerequisite for myelination, microtubules are another cytoskeletal component except of microfilaments, combined with our preliminary experimental data, we propose a novel scientific hypothesis that RhoA can regulate cytoskeletal remodeling through microtubules dynamics and further influence SC myelination. To this end, we will study the temporal and spatial changes of microtubule dynamics and its related regulatory proteins in SC, explore the effects of RhoA on the expression of microtubule dynamic regulatory proteins, and its role in SC microtubule dynamics and myelination, and explore the related mechanisms. This project will help to reunderstand the significances of RhoA signaling pathway on cytoskeleton reconstruction and its role in SC myelination and nerve injury repair. Further studies based on present data may to explore a new strategy for targeting RhoA pathway to promote the axonal regeneration and remyelination simultaneously.

过去公认RhoA主要通过ROCK通路调控微丝动态，神经损伤后RhoA高表达与激活是导致生长锥塌陷及神经再生困难的核心原因之一，抑制RhoA信号可促进神经修复。但本组前期发现抑制RhoA不利于施万细胞（SC）的髓鞘化，且RhoA并非通过ROCK对SC发挥作用。鉴于细胞骨架重构是髓鞘化的前提，微管是微丝之外另一个细胞骨架成分，结合预试验结果我们提出科学假设:RhoA可通过微管动态调控细胞骨架重构进而影响SC髓鞘化。本课题将借助RhoA条件性敲除、RNA干扰、过表达、转录组测序、生物信息学、细胞与分子生物学及动物实验等，拟阐明微管动态及其相关调控蛋白在SC髓鞘化、脱髓鞘及再髓鞘化过程的时空变化及意义；探明RhoA对微管动态调控蛋白表达的影响进而对SC微管动态和髓鞘化的作用，并探究其相关机制。本课题旨在为将来以RhoA信号或微管动态为靶向治疗脱髓鞘相关疾病及促进周围神经修复过程的髓鞘化提供新策略。

RhoA是近年来备受关注的一种细胞骨架调控的关键开关蛋白，过去的观点认为它主要通过ROCK通路调控微丝动态，神经损伤后RhoA高表达与激活是导致生长锥塌陷及神经再生困难的核心原因之一，抑制RhoA信号可促进神经修复。但课题组在前期2个国家自然科学基金资助下通过系列研究了许多不同于传统观点的发现，例如我们的曾经报道了抑制RhoA不利于施万细胞（SC）的髓鞘化，且RhoA并非通过ROCK对SC发挥作用。鉴于细胞骨架重构是髓鞘化的前提，微管是微丝之外另一个细胞骨架成分，结合预试验结果我们在本课题立项时提出科学假设:RhoA可通过微管动态调控细胞骨架重构进而影响SC髓鞘化。围绕本科学假说，本课题组在基金委的资助下，一个按照基金计划书的研究开展了系列研究，例如利用RhoA条件性敲除、RNA干扰、过表达、转录组测序、生物信息学、细胞与分子生物学及动物实验等，阐明了微管动态及其相关调控蛋白在SC髓鞘化、脱髓鞘及再髓鞘化过程的时空变化及意义；探明了RhoA对微管动态调控蛋白表达的影响进而对SC微管动态和髓鞘化的作用，并开展了一些列的相关机制研究。迄今为止课题组标注本课题编号发表的学术论文9篇，另有一篇刚刚在胶质细胞领域备受公认的杂志Glia接收（2023年2月23日证实接收，Schwann cell-specific RhoA knockout accelerates peripheral nerve regeneration via promoting Schwann cell dedifferentiation）。依托本课题培养博士生5人，硕士生5人。