Role of nitro-fatty acids in BBB stabilization and post-stroke neurovascular protection

中风是美国退伍军人的主要医疗问题之一。至少有15,000名退伍军人 每年因中风住院，大多数幸存者都患有长期的神经损伤。 不幸的是，有效疗法的开发受到严重限制。广泛的研究表明，血脑屏障 崩溃促进了一系列毁灭性的事件，促成了外周免疫的轮回 细胞，脑炎性反应，水肿，出血性转化，神经元丢失和最终 脑缺血/再灌注(I/R)后神经功能障碍。因此，有必要确定机制和 制定有效的治疗策略，保护血脑屏障的完整性，防止永久性神经血管损伤 在I/R之后。 硝基油酸(OA-NO2)是一种在一氧化氮(NO)依赖的氧化反应中形成的硝基烯烃。 在人类血浆中被发现，被认为是一种新的细胞信号媒介，调节生理 在多种单元格类型中发挥作用。已有研究表明，OA-NO2是一种内源性过氧化物酶体增殖物。 激活受体-γ(PPARγ)配体，在生理水平激活PPARγ。最近的数据表明， OA-NO2可显著减轻外周血管炎症和管腔内血管损伤。具有挑衅性的， 一些文献已经证明，在缺血再灌注条件下，OA-NO2增加，并且 减轻心脏或肾脏缺血/再灌注损伤。然而，它的功能意义和分子水平 OA-NO2调节脑血管病变，特别是血脑屏障破坏的机制及其结果 缺血性卒中的神经学结果仍未被研究。 在我们的初步研究中，我们最近首次发现静脉注射(i.v.)行政管理 OA-NO2可减少血脑屏障渗漏，减轻脑梗塞，并改善小鼠的神经行为 大脑中动脉阻塞(MCAO)。此外，我们还发现，OA-NO2显著上调了mRNA的表达 培养的脑微血管内皮细胞(BMECs)中主要BBB紧密连接蛋白的表达。 这些发现提示，硝基烯烃在脑缺血中可能起到重要的神经血管保护作用。 损坏。在这个提案中，我们将检验我们的中心假设，即OA-NO2在I/R后保持血脑屏障完整性 通过激活PPARγ和其他信号通路，减弱血脑屏障的破坏和随后的 病理性级联反应，从而引发神经血管保护。在这方面将实现三个目标 求婚。目的1：明确OA-NO2在缺血性卒中后血脑屏障功能障碍/恢复和脑损伤中的作用； 目的2：阐明OA-NO2调节卒中后血脑屏障功能障碍/恢复的机制；目的3： 探索系统地给药作为一种潜在的缺血性卒中的血脑屏障稳定疗法。澄清 OA-NO2介导的BBB稳定和恢复的分子机制可能会引导我们发现新的 有效治疗缺血性卒中的药物途径。

Stroke is one of the major medical concerns for United States veterans. At least 15,000 veterans are hospitalized every year for stroke and most survivors live with long-term neurological impairments. Unfortunately, development of effective therapies is seriously limited. Extensive studies have shown that BBB breakdown promotes a devastating cascade of events, contributing to transmigration of peripheral immune cells, cerebral inflammatory responses, edema, hemorrhagic transformation, neuronal loss and eventual neurological deficits after cerebral ischemia/reperfusion (I/R). Thus, it is necessary to identify mechanisms and develop effective therapeutic strategies that protect BBB integrity and prevent permanent neurovascular injury after I/R. Nitro-oleic acid (OA-NO2), a nitroalkene formed in nitric oxide (NO)-dependent oxidative reactions, has been found in human plasma and is thought to be a novel cell signaling mediator that regulates physiological functions in multiple cell types. It has been shown that OA-NO2 is an endogenous peroxisome proliferator- activated receptor-γ (PPARγ) ligand and activates PPARγ at physiological levels. Recent data have shown that OA-NO2 significantly reduces peripheral vascular inflammation and endoluminal vessel injury. Provocatively, several publications have documented that OA-NO2 is increased under ischemia-reperfusion conditions and attenuates cardiac or renal ischemia/reperfusion injury. However, the functional significance and molecular mechanisms of OA-NO2 in regulating cerebrovascular pathogenesis, in particular BBB disruption, and resultant neurological outcomes remain unexplored in ischemic stroke. In our preliminary studies, we have recently identified for the first time that intravenous (i.v.) administration of OA-NO2 leads to reuced BBB leakage, smaller brain infarction, and improved neurobehavior in mice after middle cerebral artery occlusion (MCAO). Moreover, we found that OA-NO2 significantly elevates the mRNA and protein expression of major BBB tight junctions in cultured brain microvascular endothelial cells (BMECs). These findings suggest that nitroalkenes may play a critical neurovascular protective role in ischemic brain damage. In this proposal, we will test our Central Hypothesis that OA-NO2 preserves BBB integrity after I/R via activation of PPARγ and other signaling pathways, attenuates BBB disruption and subsequent pathological cascades, thereby eliciting neurovascular protection. Three aims will be performed in this proposal. Aim 1: Define the role of OA-NO2 in BBB dysfunction/recovery and brain injury after ischemic stroke; Aim 2: Elucidate the mechanisms of OA-NO2 regulation of post-stroke BBB dysfunction/recovery; Aim 3: Explore systematic delivery of OA-NO2 as a potential BBB stabilizing therapy in ischemic stroke. Elucidating the molecular mechanisms of OA-NO2-mediated BBB stabilization and recovery may lead us to discover novel pharmaceutical approaches for the effective treatment against ischemic stroke.