miR-365对VEGF促进缺血损伤脑内神经胶质细胞转分化为神经元的作用及其机制研究

The mechanism of neural repair and damage of brain after ischemic stroke is very important and interesting question for neuroscientists and neurologists. Our previous studies have shown that activated astrocytes could be transdifferentiated into functional neurons in the ischemic injured brain regions, which could be enhanced by treatment of VEGF. Moreover, newly generated neurons can be rebuilt local and distal neural circuitries, which should be fundamental to remodel brain function after injury. We have reported that VEGF plays very important mediator within vascular endothelia, neuron and astrocyte, including morphological and biological functions. In the present study, we proposed that VEGF might increased transdifferentiation of astrocyte into new neurons via inhibiting miR-365-3p（miR-365) and enhanced Pax6 expression in the ischemic brains. Therefore, we used MCAO model combined with local injection of Lenti-GFAP-eGFP to trace cell fate of astrocytes in the injured brain regions. The study will illustrate that 1.the changes of miR-365 in the ischemic brain with/without VEGF treatment; 2.the effects of miR-365 agonist and antagonist on the VEGF-increase transdifferentiation of astrosytes into neuron in the ischemic brain; 3.whether miR-365 antagonist increase VEGF-mediated transdifferentiation into neurons via Pax6 expression in injured astrocytes. Through this research, we expect the results will help to develop therapeutic strategy for enhancement of neural repair or beneficial for reestablishment of neurovascular networks in the brain after ischemic stroke or traumatic injury.

缺血性脑卒中所致的脑损伤和修复机制的研究是神经科学和神经病学的前沿科学问题。我们以往的研究表明，损伤脑内激活的星形胶质细胞能转分化为有功能的新生神经元，并形成局部和远端核团间的神经网络。血管活性物质VEGF促进胶质细胞转分化为神经元，并促进神经元新生。本项目在原发现基础上，利用成年大鼠短暂性局部脑缺血实验动物模型，采用Lenti-GFAP-eGFP慢病毒脑实质内注射结合细胞命运示踪法等技术，从表观遗传角度深入研究VEGF促进胶质细胞转分化为新生神经元的作用及其分子机制。 研究将阐明miR-365-3p（简称 miR-365) 在活化型星形胶质细胞转分化为新生神经元中的作用及其机制；阐明miR-365 在VEGF促进损伤脑内神经元新生中的作用及其分子和细胞机制；研究结果有助于阐明损伤脑内神经血管网络重构的分子和细胞机制。研究希望为提高临床脑中风的效疗的研发提供新的理论依据。

本项目利用成年大鼠短暂性局部脑缺血实验动物模型，采用enti-GFAP-eGFP慢病毒脑实质内注射结合细胞命运示踪法等技术，研究返现：1.miR-365拮抗剂取消对Pax6上游靶向抑制，促进星形胶质细胞向神经元转分化；2；miR-365拮抗剂取消对Oxr1上游靶向抑制，促进损伤脑抗氧化和脑保护作用；3.VEGF促星胶细胞向神经元转分化通过MAPK/Erk通路抑制miR-365表达而实现的。VEGF具有调节星形胶质细胞对OGD诱导钙内流作用，从而，使胶质细胞免遭损伤。研究发表论文年篇，获得国家专利1项，培养博士6名。