Ryanodine受体介导钙信号调控成髓鞘细胞分化发育的作用机制研究

It has been demonstrated that calcium signaling is involved in the process of myelination and demyelination injuries. Ryanodine receptors(RyRs) are important channels responsible for the regulation of intracellular Ca2+ . But to date it remains elusive about its development, function response characteristics and role in the non-excitable oligodendrocytes(OLs). Studies have shown that intracellular calcium signal has a regulative role during early development events by antagonizing the Wnt/β-catenin pathways. Based on our preliminary work that RyR3 is highly expressed in the early stage of OL and the differentiation is interfered after blocking RyR channel,we speculate that RyR mediated calcium signaling plays a significant onset role in the differentiation of oligodendrocyte progenitor cells(OPCs) towards OLs, and the process may be mediated by the Wnt pathway.In the present project, we will investigate the spatio-temporal expression changes of RyRs, its functional responsive feature and three-dimensional calcium wave transmission mode, by establishing the purified OLs culture system (myelin development) in vitro and demyelination model in vivo.And the interaction between RyR and its associated calcium channels will also be examined. Then the influence of RyR mediated calcium signal on the Wnt/β-catenin pathway and the OLs differentiation transcription factors, will be studied by using a combination of pharmacological intefering and gene disruption/over-expression techniques. We will also explore the functional role of RyRs activity by using the development and demyelination mouse models. The results will contribute to elucidate the calcium signal involved mechanisms during myelin sheathing cell differentiation, so as to provide new clues for the treatment of demyelinating diseases by targeting RyRs calcium channels.

钙信号参与髓鞘发育与损伤等过程已有众多实验证实。Ryanodine受体(RyR)是胞内Ca2+调控的重要通道，在少突胶质细胞(OL)其发育、功能应答特征及作用尚不清楚。研究显示胞内Ca2+可通过拮抗经典Wnt途径调控少突胶质前体细胞（OPC）向OLs分化，结合前期工作发现RyR在OL早期阶段性高表达及阻断其功能影响OL分化的观察，我们推测RyR介导钙信号是OPCs分化启动的重要调控环节，该过程可能经由Wnt途径介导。课题拟从离体与在体两方面，观察OPC/OL分化发育中RyR功能应答特征和钙波传递模式，和其它钙通道的相互作用；结合药理调控及基因干扰、过表达等技术，研究RyR启动钙信号对Wnt信号途径和OL定向分化转录因子的调节；通过在体发育和脱髓鞘模型，探讨RyR功能活动对髓鞘发育的影响。结果将有助于阐明成髓鞘细胞分化发育的钙信号调节机制，为以钙通道为靶点的脱髓鞘疾病治疗策略提供新线索。

本研究课题拟从离体与在体两方面，研究并观察少突前体细胞OPC/少突胶质细胞OL分化发育中钙通道受体RyR的功能应答特征和钙波传递模式，及与其它钙通道的相互作用。通过结合小分子化合物等药理调控及基因干扰、过表达等技术，研究钙通道受体RyR启动钙信号对OL定向分化转录因子和信号途径的调节；通过在体发育和脱髓鞘模型的研究，探讨RyR功能活动正常与否对髓鞘发育的影响。结果显示分化早期仅RyR3高表达，钙信号变化具有显著发育阶段依赖性，且介导了OLs分化转录因子和髓鞘相关蛋白表达的增加。慢性脑损伤缺氧下胞内钙信号则增强异常，降低髓鞘相关蛋白的表达，PreOLs的分化与成熟被显著抑制。慢性脑损伤缺氧后阻止钙动力的异常可为脱髓鞘病变的发生及促进髓鞘再恢复新手段，也可为以钙通道为靶点的脱髓鞘疾病的治疗策略提供新线索。