少突胶质细胞前体细胞的分化成熟是其包裹神经轴突成髓鞘而发挥功能的基础。少突胶质细胞的分化过程中一个非常重要的表现在于其细胞膜表面积的急剧增加，我们发现Rab相关的内膜转运系统在其成熟过程中起着重要的作用。我们发现在多发性硬化等中枢神经系统脱髓鞘疾病发病过程中崩解的髓鞘碎片会使Rab蛋白的效应蛋白MARCKS发生磷酸化，我们推测这一过程可能抑制Rab相关囊泡的上膜，并抑制少突胶质细胞的分化成熟，这可能是脱髓鞘疾病病人重新成髓鞘失败的主要原因。我们拟通过本项目的研究详细了解在少突胶质细胞分化成熟过程中髓鞘抑制性因子是如何通过MARCKS调节Rab相关囊泡的上膜并为了解重新成髓鞘机制提供基础。

Oligodendrocyte precursor cell (OPC) differentiation contributes significantly to myelin sheath.This process need amount of membrane addition. There have been reported that the Rab system contribute to this process in other cell types. We want to learn whether the Rabs are nessary for OPC maturetion? the myeline debris specifically inhibit differentiation of patients' own OPCs，which inhibit remyelination in MS disease. It is interesting to research how to promote the remyelination by facilitated the patient's own OPC differentiation . We found the myelin debris can promote OPC MARCKS phosphorylated which is the Rabs' effect protein. The phosphorylated MARCKS will translocated from plasma membrane to cytosol.Which will inhibits the Rabs function on membrane addition. In this project we want learn how myelin debris regulate MARCKS phosphorylation and inhibit Rabs membrane insertion. Our results, which will provide a mechanistic link between myelin debris, membrane protein and PPV membrane insertion associated with demyelinating pathologies amenable to pharmacological manipulation, are therefore of significant potential value for future strategies aimed at enhancing CNS remyelination.

从少突胶质细胞前体细胞分化为成熟的包裹神经轴突的髓鞘细胞需要形成非常大面积的细胞膜结构，而这个从细胞内高尔基体到细胞膜表面的囊泡运输过程一般是由Rab相关蛋白介导的。我们在本项目中发现少突胶质细胞的成熟主要与Rab10小G蛋白相关。我们不论是用小的SiRNA还是RNA干扰质粒表达的发夹RNA去敲减Rab10都会显著抑制少突胶质细胞的分化成熟。我们还发现Rab10的显性负调的突变体也会显著抑制少突胶质细胞的分化成熟。同时Rab10条件性敲除模型用免疫组化和电镜观察也发现在髓鞘形成期即出生后1天到16天时在少突胶质细胞内敲除Rab10会显著阻碍髓鞘的发育。因为之前我们已经证明MARCKS介导了Rab10相关囊泡的上膜，随后我们也鉴定了MARCKS在少突胶质细胞前体细胞发育中的作用。我们发现不论用RNA干扰质粒表达的发夹RNA去敲减MARCKS还是过表达抑制MARCKS与Rab10结合的肽段都会显著抑制少突胶质细胞的分化成熟。说明MARCKS与Rab10的结合在少突胶质细胞的发育过程中是必须的。同时我们还发现在培养在Nogo66或者髓鞘碎片的上的少突胶质细胞分化受到明显的抑制同时伴随有MARCKS的磷酸化的增加。用PP2A的激动剂DES处理抑制MARCKS的磷酸化可以促进培养在髓鞘碎片上的少突胶质细胞分化成熟。提示抑制MARCKS磷酸化的药物有可能用于中枢神经系统损伤或者脱髓鞘疾病的治疗。