Oligo-Vascular Signaling in Stroke

描述（由申请人提供）：脑卒中白质损伤中的少血管信号是多种中枢神经系统疾病（包括脑卒中和血管性痴呆）病理生理学中的核心事件。但在脑血管研究中，研究白质的研究相对较少。越来越多的证据表明，脑内皮细胞除了传导血液外还有多种功能。在这里，我们假设脑内皮细胞分泌营养因子来维持少突胶质细胞（OL）和少突胶质前体细胞（OPC）的存活和功能。我们的3个目标是：目的1：解剖内皮源性生长因子的寡聚保护的细胞机制。培养的大鼠OL/OPC将进行氧糖剥夺。内皮条件培养基（Endo-CM）将用于测试内皮细胞的生长因子是否可以保护OL/OPC培养物。我们将研究Endo-CM如何促进生存信号（如Akt）并减少OL/OPC的凋亡。目的2：表明氧化应激降低内皮生长因子的产生。我们假设，即使没有明显的细胞死亡，氧化应激内皮细胞也会减少生长因子的产生。脑内皮细胞将暴露在氧化应激下，我们比较了健康内皮细胞和氧化应激内皮细胞的条件培养基。来自氧化应激内皮细胞的条件培养基应该含有较少的生长因子，因此，对OL/OPC的保护作用较弱。目的3：证明内皮生长因子对体内OL/OPC的重要作用。在各种脑缺血小鼠模型中，我们将评估胼胝体和纹状体的OL/OPC完整性（即白质损伤）。内皮特异性基因递送方法（脂质体，scAAV9）将用于体内调节内皮营养因子。我们预测，选择性地增加内皮营养因子保护白质，而减少内皮营养因子使白质更脆弱。我们的试点数据（Arai和Lo， J Neurosci 2009）表明Endo-CM通过特定的信号通路支持OPC增殖，氧化应激干扰少血管偶联。在本提案中，我们将在这些初步发现的基础上，证明Endo-CM确实可以预防OL/OPC的细胞死亡。最重要的是，我们的目标是在体内证明少血管偶联可以预防中风。这些实验为内皮和OL/OPC之间的营养耦合维持和保护白质提供了证据。

DESCRIPTION (provided by applicant): Oligo-Vascular Signaling in Stroke White matter injury is a central event in the pathophysiology of diverse CNS disorders, including stroke and vascular dementia. But studies that investigate white matter are relatively uncommon in cerebrovascular research. Accumulating evidence suggest that cerebral endothelial cells have multiple functions in addition to conducting blood flow. Here, we hypothesize that cerebral endothelial cells secrete trophic factors to maintain oligodendrocyte (OL) and oligodendrocyte precursor cell (OPC) survival and function. Our 3 aims are: Aim 1: Dissect the cellular mechanisms of oligo-protection by endothelial-derived growth factors. Cultured rat OL/OPC will be subjected to oxygen-glucose deprivation. Endothelial conditioned media (Endo-CM) will be used to test whether growth factors from endothelial cells can protect OL/OPC cultures. We will investigate how Endo-CM promotes survival signaling (e.g. Akt) and decreases apoptosis in OL/OPC. Aim 2: Show that oxidative stress decreases endothelial growth factor production. We hypothesize that even without overt cell death, oxidatively-stressed endothelial cells will have reduced growth factor production. Cerebral endothelial cells will be exposed to oxidative stress, and we compare conditioned media from healthy endothelial cells vs oxidatively-stressed endothelial cells. Conditioned media from oxidatively-stressed endothelial cells should have less growth factors and thus, be less protective for OL/OPC against insults. Aim 3: Demonstrate that endothelial growth factors are important for OL/OPC in vivo. In various mouse models of cerebral ischemia, we will assess OL/OPC integrity in corpus callosum and striatum (i.e. white matter damage). Endothelial-specific gene delivery methods (liposome, scAAV9) will be used to modulate endothelial trophic factors in vivo. We predict that selectively increasing endothelial trophic factors protect white matter, whereas decreasing endothelial trophic factors makes white matter more vulnerable. Our pilot data (Arai and Lo, J Neurosci 2009) suggest that Endo-CM supports OPC proliferation via specific signaling pathways and oxidative stress interferes with oligovascular coupling. In this proposal, we will build on these initial findings to show that Endo-CM can truly prevent cell death in OL/OPC. And most importantly, we aim to show that oligovascular coupling protects against stroke in vivo. These experiments should provide evidence to show that trophic coupling between endothelium and OL/OPC maintains and protects white matter.