Oligo-Vascular Signaling in Stroke

描述（由申请人提供）：卒中中的寡血管信号传导白色物质损伤是多种CNS疾病（包括卒中和血管性痴呆）病理生理学的中心事件。但在脑血管研究中，研究白色物质的研究相对较少。越来越多的证据表明，脑内皮细胞除了传导血液流动外还具有多种功能。在这里，我们假设，脑内皮细胞分泌营养因子，以维持少突胶质细胞（OL）和少突胶质细胞前体细胞（OPC）的生存和功能。我们的三个目的是：目的1：探讨内皮源性生长因子寡核苷酸保护的细胞机制。将对培养的大鼠OL/OPC进行氧-葡萄糖剥夺。将使用内皮条件培养基（Endo-CM）检测内皮细胞生长因子是否可保护OL/OPC培养物。我们将研究Endo-CM如何促进OL/OPC中的存活信号传导（例如Akt）并减少凋亡。目的2：表明氧化应激减少内皮生长因子的产生。我们假设，即使没有明显的细胞死亡，氧化应激的内皮细胞将减少生长因子的生产。脑内皮细胞将暴露于氧化应激，我们比较了条件培养基从健康的内皮细胞与氧化应激的内皮细胞。来自氧化应激内皮细胞的条件培养基应具有较少的生长因子，因此对OL/OPC抵抗损伤的保护性较低。目的3：证明内皮生长因子对体内OL/OPC的重要性。在各种小鼠脑缺血模型中，我们将评估胼胝体和纹状体中的OL/OPC完整性（即白色物质损伤）。内皮特异性基因递送方法（脂质体，scAAV 9）将用于在体内调节内皮营养因子。我们预测，选择性增加内皮营养因子保护白色物质，而减少内皮营养因子使白色物质更脆弱。 我们的初步数据（Arai和Lo，J Neurosci 2009）表明，Endo-CM通过特定的信号传导途径支持OPC增殖，氧化应激干扰少血管偶联。在这项提案中，我们将建立在这些初步研究结果的基础上，以表明Endo-CM可以真正防止OL/OPC中的细胞死亡。最重要的是，我们的目标是证明少血管偶联在体内预防中风。这些实验应提供证据表明，内皮细胞和OL/OPC之间的营养偶联维持和保护白色物质。

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.