颅脑创伤后神经干细胞RBM3通过可变剪接增强外泌体circWdr33修复神经元受损突触的机制研究

神经干细胞参与颅脑创伤（TBI）后受损神经元突触的修复，但机制不明。我们前期发现：冷休克蛋白RBM3通过与Wdr33前体mRNA结合，影响其可变剪接上调神经干细胞外泌体内环状RNA-circWdr33表达。富含circWdr33的神经干细胞外泌体可促进TBI小鼠受损神经元突触的修复。进一步实验表明：circWdr33可结合Nova2蛋白，减少其与E3泛素酶RNF180结合，抑制Nova2泛素化降解，进而促进受损突触修复。故我们推测：TBI后RBM3通过可变剪接上调神经干细胞外泌体内circWdr33表达，后者传递至损伤神经元中结合Nova2蛋白，抑制RNF180介导的Nova2泛素化降解，促进神经元受损突触修复。我们拟采用神经元牵张损伤模型、小鼠脑皮质损伤模型，病毒载体等方法，阐明RBM3通过外泌体途径介导神经干细胞修复神经元受损突触的机制，为TBI后神经功能修复治疗提供新方向及作用靶点。

Neural stem cells (NSCs) play a critical role in the repair of damaged synapses after traumatic brain injury (TBI). However, the mechanism is still unknown. Our previous study found that the cold shock protein RBM3 combined with pre-mRNA of Wdr33 to increase the expression of exosomal circular RNA-circWdr33 derived from NSCs through alternative splicing. Moreover, circWdr33 enriched exosomes derived from NSCs could promote the repair of damaged synapses in the pericontusion region after TBI in mice. Further experiments showed that circWdr33 could bind to Nova2 to inhibit RNF180 mediated ubiquitination degradation of Nova2, which can promote the repair of damaged synapses. Therefore, we propose a hypothesis: RBM3 increases the expression of circWdr33 in exosomes derived from NSCs through alternative splicing after TBI. These circWdr33 enriched exosomes can transmit to injured neurons and bind to Nova2 to inhibit RNF180 mediated ubiquitination degradation of Nova2, which can promote the repair of damaged synapses. We intend to clarify the role of RBM3 regulated exosomes derived from NSCs in the repair of damaged synapses by using stretch injury model of neurons, controlled cortical impact model of mice and virus vector. Our study may provide a new therapeutic target for rehabilitation of neurological function after TBI.