小胶质细胞Hv1介导HIF-1a通路参与脊髓损伤后神经血管单元结构和功能重建的机制研究

Recent researches in neuroscience suggest that the maintenance and functional coupling of the neurovascular unit (NVU) is vital to the spinal cord injury and functional reconstruction. After spinal cord injury, the dysfunction of microglia caused by excessive activation is an important initiator of the secondary injury in NVU. Our previous work found that: In central nervous system, voltage gated proton channel Hv1 is selectively and functionally expressed in microglia. Knockout microglia HV1 channel can significantly reduced the expression of hypoxia-inducible factor-1a (HIF-1a) pathway related protein after spinal cord injury. Recent studies have shown that the HIF-1a pathway is a key integrator of cell–cell communication in the NVU and regulate the function and structure of NVU through their multi-cellular protective profile. Therefore, we speculate microglia Hv1 may regulate the components of NVU by interfering with the downstream of HIF-1a pathway." In this project,we aim to explore the regulatory mechanism of microglia Hv1 on HIF-1a pathway under spinal cord injury, and mainly study whether specific regulation of Hv1 can play a multi-protective role in NUV through the HIF-1a pathway, then promotes neural functional recovery and uncover its mechanism. This project may provide new ideas and potential therapeutic targets for the clinical treatment of spinal cord injury.

神经科学的最新进展提示神经血管单元（NVU）稳态维持及功能耦合是决定脊髓损伤及功能重建的关键。脊髓损伤后小胶质细胞过度活化导致的功能失调是损伤后NVU继发性损伤级联反应中的重要始动因素。我们的前期工作发现：中枢神经系统的小胶质细胞特异性表达电压门控质子通道Hv1，敲除小胶质细胞HV1通道可显著下调脊髓损伤后低氧诱导因子HIF-1a通路相关蛋白的表达。新近研究表明HIF-1a通路可通过多靶点调控神经血管单元结构和功能的完整性。据此，我们推测“脊髓损伤后，小胶质细胞Hv1通道可能通过干扰下游HIF1a通路参与神经血管单元各组分的调控过程。”本项目拟阐明脊髓损伤后小胶质细胞Hv1对HIF-1a通路的调控机制，并重点研究Hv1靶向调控是否可通过HIF-1a通路对神经血管单元发挥多靶点作用，而促进神经功能恢复及其机制；以期为为临床脊髓损伤的治疗提供新的思路和潜在治疗靶点。

脊髓损伤后小胶质细胞过度活化导致的功能失调是损伤后NVU继发性损伤级联反应中的重要始动因素。我们的研究发现1.敲除小胶质细胞电压门控质子通道（Voltage gated proton channel，Hv1）可显著下调脊髓损伤后活性氧(Reactive oxygen species, ROS)产生及低氧诱导因子HIF-1a通路相关蛋白的表达，通过多靶点调控神经血管单元结构和功能的完整性。2.明确了脊髓损伤后神经元焦亡及凋亡时间和空间分布模式不同。小胶质细胞Hv1通道敲除通过抑制小胶质细胞活化及活性氧的产生可减少神经元焦亡与凋亡及焦亡通道蛋白NLRP3炎症小体表达，并且调节星形胶质细胞活化表型，促进A2型反应性星形胶质细胞表型基因的表达，抑制脊髓损伤后A1型反应性星形胶质细胞，促进星形胶质细胞EAAT2和Cx43磷酸化水平的表达、吞噬功能以及星形胶质细胞兴奋性突触形成因子的表达，从而减缓髓鞘及轴突损害进而促进神经功能恢复。本研究发现为寻求脊髓损伤新的治疗靶点提供了新的思路。