SUMOs化温敏干细胞挽救脑缺血半暗带神经元的基础研究

Internationally, we have previously established a thermosensitive stem cell line, and made a series of studies on its growth characteristics at mild hypothermia. Our results demonstrated that the thermosensitive stem cell line can survive at conditions of mild hypothermia，and play a role in the traumatic repair after its transplantation in the penumbra. However, several problems have been found as follows. ① The local microenvironment in the penumbra after traumatic brain injury is complicated，which will be unfavourable for the further judgement and analysis of the results. ② The fusion stem cells will eventually differentiate into glial cells and form glial scars, and few of them will differentiate into neurons, the executive cells with nerve function. ③ Synaptic transmission fails in the neurons of the penumbra, and previous work seldom improved information transmission among neurons. On the basis of former study, we will generate a thermo-sensitive stem cell line modified by SUMOs. With the specific protection of SUMO-2/3 for neurons, the improved signal transmission between cells with SUMO-1, and the enhanced SUMOs binding protein under mild hypothermia, we will use the oxygen glucose deprivation-exposed neuron model in vitro and the neuron-specific SUMOs transgenic mouse model with the middle cerebral artery occlusion, and attempt to retrieve neurons in the brain ischemic penumbra efficiently and maximally recover the motive and sensory nerve function.

前期我们在国际上建立了首株温度敏感型干细胞系，对其在亚低温环境下的生长特征做了系列研究。结果证实该温敏型干细胞系可在亚低温环境下存活，并在大鼠脑创伤半暗带移植后发挥创伤修复作用，但同时也暴露出新的问题：①脑创伤半暗带局部微环境复杂，不利于后续结果判断和分析；②被融合的干细胞最终多分化为胶质细胞，形成胶质疤痕，却极少分化为神经功能的执行细胞--神经元；③半暗带神经元处于"突触传递衰竭"状态，前期工作对改善神经元间信息传递作用甚微。本研究将在前期基础上，建立类泛素化（SUMO）基因修饰的温敏型干细胞系，利用SUMO-2/3对神经元的特异性保护作用和SUMO-1改善细胞间神经递质传递的机制，以及亚低温对SUMOs结合靶蛋白的增强作用，对体外培养的氧糖剥夺神经元模型和神经元特异性SUMOs转基因小鼠大脑中动脉梗塞模型进行实验研究，以期有效挽救脑缺血半暗带神经元，最大化恢复运动和感觉神经功能。

前期我们在国际上建立了首株温度敏感型干细胞系，对其在亚低温环境下的生长特征做了系列研究。结果证实该温敏型干细胞系可在亚低温环境下存活，并在大鼠脑创伤半暗带移植后发挥创伤修复作用，但同时也暴露出新的问题：①脑创伤半暗带局部微环境复杂，不利于后续结果判断和分析；②被融合的干细胞最终多分化为胶质细胞，形成胶质疤痕，却极少分化为神经功能的执行细胞——神经元；③半暗带神经元处于“突触传递衰竭”状态，前期工作对改善神经元间信息传递作用甚微。本研究在前期基础上，成功建立了类泛素化（SUMO）基因修饰的温敏型干细胞系，然后利用SUMO-2/3对神经元的特异性保护作用和SUMO-1改善细胞间神经递质传递的机制，以及亚低温对SUMOs结合靶蛋白的增强作用，对体外培养的氧糖剥夺神经元模型和神经元特异性SUMOs转基因小鼠大脑中动脉梗塞模型进行实验研究，结果发现SUMO过表达的温敏型干细胞能够更为有效地挽救脑缺血半暗带神经元，更好地恢复运动和感觉神经功能。