小胶质细胞电压门控质子通道Hv1与脑白质缺血的机制研究

With the progress of China's aging, the incidence of cognitive dysfunction ischemic leukoencephalopathy significantly increased.Recently numerous studies have confirmed the white matter ischemic damage may have specific molecular mechanisms and involve different ion channels and protein kinases. Microglia activation and proliferation were showed in the white matter after myelin damage, but the specific molecular mechanism of microglia caused white matter damage is not yet clear. Phagocytic cell NADPH oxidase (NOX) generates reactive oxygen species (ROS) as part of innate immunity. Hv1 is required for full NOX activity since it compensates for loss of NOX-exported charge. In the preliminary study，we found that Hv1 is required for NOX-dependent ROS generation in brain microglia in situ and in vivo. Mice lacking Hv1 were protected from NOX-mediated neuronal death and brain damage 24 hours after stroke. Therefore, we speculate Hv1 may be the trigger switch of NOX activity in microglia in the process of white matter ischemic damage. By using the Hv1 knockout mice combined with molecular biology and electrophysiological methods, this study aims to explore the molecular mechanisms of microglia Hv1 involved in white matter ischemia, and try to provide new ideas and potential therapeutic targets for the clinical treatment of nervous system damage.

随着我国老龄化的进程，缺血性脑白质病变以及所导致的认知功能障碍发生率明显增加。近年来有研究表明在白质缺血性损害过程中小胶质细胞随着神经元轴突和髓鞘的损伤而显著活化，但其与白质损伤具体分子机制的尚不明确。NADPH氧化酶通过催化电子从 NADPH转移至分子氧而产生ROS，这个催化过程需要电压门控质子通道Hv1的参与。我们前期研究证明中枢神经系统Hv1选择性表达在小胶质细胞，而小胶质细胞Hv1与NADPH氧化酶的耦合而产生ROS导致神经元凋亡。因此我们推测Hv1可能是缺血脑白质损伤过程中调控小胶质细胞NOX活性的触发开关。本研究借助Hv1基因敲除小鼠，结合分子生物学及电生理方法探讨小胶质细胞Hv1参与脑白质缺血的分子机制，为临床神经系统损伤的治疗提供新的思路和潜在治疗靶点。

缺血性脑白质病变是导致血管性认知功能障碍的主要原因之一。在长期慢性缺血的情况下，大脑的原位免疫细胞小胶质细胞会出现活化并产生一系列生物介质。电压门控质子通道Hv1是一种近期被发现的离子通道，它对质子具有高度的选择性，且在中枢神经系统中仅特异的表达于小胶质细胞上。Hv1主要通过对细胞内质子的外排来起到帮助NADPH氧化酶产生活性氧的作用。本研究以电压门控能够质子通道Hv1为调控靶点，研究其在慢性低灌注导致的白质损伤中的作用及可能的作用机制。我们发现慢性低灌注可以造成脑白质的脱髓鞘改变以及认知功能缺损，期间伴随着小胶质细胞的活化和少突胶质细胞系的损伤和分化障碍。选择性敲除Hv1可以减轻白质损伤和认知功能的降低，这可能是通过抑制小胶质细胞产生活性氧以及促炎因子，进而促进了少突胶质细胞系的存活和分化成熟实现的,提示Hv1有望成为低灌注导致的脑白质缺血性损伤的治疗靶点。