Vascular-Glial Signaling in Neurovascular Injury

项目总结 中风和创伤性脑损伤(TBI)会导致血管系统的改变，扰乱神经血管单位 (NVU)，并导致神经炎症和神经元死亡。作为对血管损伤的反应，血管内的胶质细胞 中枢神经系统(CNS)、星形胶质细胞和小胶质细胞产生促炎细胞因子 导致神经元死亡。然而，连接受损的神经血管系统和胶质细胞的特定信号 受伤后的反应仍有待了解。眼睛作为中枢神经系统的组织，可以让我们研究这种相互作用 在血管和神经胶质细胞之间。与人类病理相似的小鼠视网膜静脉阻塞(RVO) 导致视网膜水肿、炎症和神经元死亡；为研究这些相互作用提供了一个模型。vbl.使用 这个模型，我们实验室以前的研究确定了caspase-9的非凋亡性激活，即 通常与内皮细胞的死亡有关。抑制caspase-9或从基因上将其从 内皮，保护视网膜免受浮肿和神经元死亡的伤害。这些结果表明，基因的表达 内皮细胞caspase-9(EC-CASP9)可导致血管损伤后的神经退行性变。此外，我们发现， 抑制caspase-9显著降低caspase-6的活性(行刑的caspase可以是 由caspase-9激活)在星形胶质细胞中激活，但不在小胶质细胞中激活。星形胶质细胞中caspase-6的激活与 GFAP的裂解和超聚集增加以及促炎细胞因子的产生。我假设 EC CASP9的非凋亡性激活增加了星形胶质细胞caspase-6，这将导致 GFAP、炎性细胞因子的产生和神经退行性变P-RVO。这样做的长期目标是 建议研究caspase-9信号在血管-神经胶质细胞通讯中的作用及其在 促炎症细胞因子和神经退行性变增加。对EC CASP9 KO小鼠的研究表明EC CASP9激活星形胶质细胞caspase-6。进一步检测caspase-9信号在血管星形胶质细胞中的作用 ，我们将确定星形胶质细胞caspase-9(1)是否位于星形胶质细胞caspase-6的上游，并介导 GFAP在RVO中的裂解，(2)增加促炎细胞因子的产生，以及(3)导致视网膜 神经元死亡和视觉通路功能障碍。了解神经血管损伤中的血管-神经胶质信号转导 有助于发现神经保护的新治疗靶点。博士后阶段的重点 将研究神经胶质细胞中的caspase信号及其在视神经炎视网膜神经节丢失中的作用 与多发性硬化(MS)相关。这份F99/K00提案的最终目标是让我成为一名 首席研究员和研究神经退行性疾病中神经炎症是如何调节的 这也会影响眼睛。为了实现这些目标，我与导师和合作者一起制定了一个计划，以指导 我的具体研究和专业活动。拥有科学和职业发展的机会 在哥伦比亚大学，这项提案的目标有望实现。

PROJECT SUMMARY Stroke and traumatic brain injury (TBI) cause alterations to the vasculature, disrupting the neurovascular unit (NVU) and causing neuroinflammation and neuronal death. In response to vascular damage, glial cells of the central nervous system (CNS), astrocytes and microglia, produce pro-inflammatory cytokines that can contribute to neuronal death. However, the specific signaling that connects the damaged neurovasculature to the glial response after injury remains to be understood. The eye, as CNS tissue, allow us to study the interactions between the vasculature and glial cells. Similar to human pathology, Retinal Vein Occlusion (RVO) in mice causes retinal edema, inflammation, and neuronal death; providing a model to study these interactions. Using this model, previous studies in our lab identified non-apoptotic activation of the protease caspase-9, that is usually associated with cell death, in the endothelium. Inhibiting caspase-9 or genetically deleting it from the endothelium, protects the retina from edema and neuronal death. These results indicated that expression of endothelial caspase-9 (EC Casp9) leads to neurodegeneration after vascular injury. Furthermore, we discovered that inhibiting caspase-9 significantly reduces the activity of caspase-6 (executioner caspase that can be activated by caspase-9) in astrocytes, but not microglia. Activation of caspase-6 in astrocytes is associated with increased cleavage and hyper-aggregation of GFAP and production of pro-inflammatory cytokines. I hypothesize that non-apoptotic activation of EC Casp9 increases astroglial caspase-6 which will result in the cleavage of GFAP, production of inflammatory cytokines, and neurodegeneration P-RVO. The long-term objective of this proposal is to study the role of caspase-9 signaling in vascular-glial communication and its contribution to increased pro-inflammatory cytokine and neurodegeneration. Studies in EC Casp9 KO mice revealed that EC Casp9 activates astroglial caspase-6. To further test the role of caspase-9 signaling on vascular-astroglial communication, we will determine if astroglial caspase-9 (1) is upstream of astroglial caspase-6 and mediates GFAP cleavage in RVO, (2) increases the production of pro-inflammatory cytokines, and (3) leads to retinal neuronal death and visual pathway dysfunction. Understanding vascular-glial signaling in neurovascular injury can help in the discovery of novel therapeutic targets for neuroprotection. The focus of the postdoctoral phase will be to study caspase signaling in glial cells and its contribution to retinal ganglion loss in Optic Neuritis associated with Multiple Sclerosis (MS). The ultimate goal of this F99/K00 proposal is to prepare me to be a principal investigator and study how neuroinflammation is regulated in neurodegenerative diseases of the brain that also affect the eye. To accomplish these goals, I developed a plan with mentors and collaborators to guide my specific research and professional activities. With the opportunities for scientific and career development available at Columbia, the objectives of this proposal are expected to be achieved.