光遗传学控制的线粒体活性调整血管平滑肌的舒缩力来促进新生小鼠中风后大脑修复

每4000位围产儿有1个脑动脉梗阻中风案例，脑梗后作为血管关键成分之一的血管平滑肌(vSMC)会发生痉挛，阻碍了微循环。 但它在脑梗后自我修复及舒缩力变化的动态机制尚不清楚。我们前期研究表明幼鼠和成年鼠的vSMC在小动脉梗后会痉挛和自我修复，故我们假设:乳鼠局灶性脑梗(dMCAO)后，脑内小动脉的vSMC也会痉挛导致舒缩力异常和vSMC自我修复事件，且线粒体活力改变参与此过程。本项目将:1)跟踪记录脑内在乳鼠脑缺血后vSMC形态、vSMC的线粒体运动性，微动脉血管直径和血流速度的动态变化;2) 通过结合生物传感器和光遗传学可逆性地控制线粒体活力研究其对vSMC舒缩力的影响；3)用光遗传学技术增强线粒体膜电位来增进vSMC舒缩力和自我修复,明确vSMC舒缩力的改变促进半暗带血灌进而促进修复大脑的目标。研究成果会提供新生小鼠缺血后脑细胞和微循环修复机制，为围产儿中风治疗提供理论依据。

Perinatal arterial ischemic stroke (PAS) occurs with an incidence of 1:4000. The mechanisms of brain damage and repair of preterm and in term infants are obscure. Vascular smooth muscle cells (vSMC) play pivotal roles in regulating microcirculations and become stiff after ischemia. But how the capability of vSMC to contract and to relax properly contributes to sufficient microcirculation is unknown and its underlying cellular mechanisms during ischemia are lacking. Our previous study has indicated that vSMC becomes constricted and exhibit self-repair in juvenile mice and in the adults. It has been long known that mitochondria become dysfunctional under ischemia. Thus, we hypothesize that vSMC of the perinatal mouse (P3-5) lost the control of vascular tone due to mitochondria failure after distal middle cerebral occlusion (dMCAO). Therefore this proposal will perform three aspects of experiments: 1) Determine the changes of vSMC morphology, mitochondrion motility, arteriole diameter, and blood cell flow velocity at the same time by using SMACreER: Mi2018 mouse. 2) Using a mechanical sensor produced by 3D printing to determine the force changes in vSMC after optogenetically manipulation of mitochondrion activity. 3)Promote the capacity of vSMC to contract and relax via optogenetic activation of mitochondria and to determine its effects on brain repair in perinatal stroke. This work will provide a new insightful treatment strategy for brain injury and might provide new therapeutic cell targets for PAS.