Nitroalkene-Mediated Vascular Protection and Ischemic Stroke

描述（由申请人提供）：缺血性中风是由暂时性或永久性局部脑血流量减少引起的，以一系列细胞紊乱为特征。中风的死亡率为30%，是美国第三大死亡原因，也是导致成人残疾的主要原因。不幸的是，由于缺血后不可逆脑损伤的迅速发展，有效治疗的发展受到严重限制。近年来，越来越多的数据表明，过氧化物酶体增殖物激活受体-3 （PPAR3）和血管紧张素II (Ang II) 1型受体（AT1R）是缺血性脑损伤发病机制中的两种重要介质。硝酸油酸（OA-NO2）和亚油酸（LNO2）是在一氧化氮（NO）依赖的氧化反应中形成的硝基烯，已在人体血浆中被发现，并被认为调节多种细胞类型的生理功能。值得注意的是，我们发现OA-NO2和LNO2都是内源性的PPAR3配体。此外，我们的初步研究也首次证实，在大脑中动脉（MCA）闭塞24小时后，脑室内给药OA-NO2可以减少小鼠脑梗死体积和水肿。此外，我们发现OA-NO2可以结合AT1R并抑制其在血管平滑肌细胞（VSMCs）中的信号传导。此外，我们还发现OA-NO2可以抑制氧葡萄糖剥夺（OGD）后大脑VSMCs和脑血管内皮细胞（CECs）的炎症反应。这些发现表明，硝基烯在缺血性脑损伤中起着重要的保护作用。在本提案中，我们将验证硝基烯烃（如OA-NO2）可能通过抑制AT1R信号通路和激活ppar3依赖性级联来抑制脑缺血诱导的血管炎症发挥神经元保护作用的中心假设。具体来说，我们将定义1)OA-NO2通过AT1R和PPAR3信号通路抑制ogd诱导的脑血管细胞炎症；2)血管选择性激活PPAR3参与OA-NO2在缺血性脑卒中中的神经元保护作用；3)血管选择性抑制AT1R信号有助于OA-NO2在缺血性脑卒中中的神经元保护作用。通过对oa - no2在脑缺血中的脑保护机制的研究，可以更好地理解硝基烯在缺血性脑卒中中的内源性信号作用，并为合理设计药物和开发硝基烯衍生物治疗脑卒中提供新的视角。

DESCRIPTION (provided by applicant): Ischemic stroke results from a transient or permanent local reduction of cerebral blood flow, characterized by a set of cellular disturbances. With a mortality rate of 30%, stroke is the third leading causes of death and the leading cause of adult disability in the United States. Unfortunately, development of effective therapies is seriously limited by the rapid development of irreversible brain injury following ischemia. Recently, increasing data suggest that peroxisome proliferator- activated receptor-3 (PPAR3) and angiotensin II (Ang II) type 1 receptor (AT1R) are two critical mediators in the pathogenesis of ischemic brain damage. Nitrated oleic acid (OA-NO2) and linoleic acid (LNO2), nitroalkenes formed in nitric oxide (NO)-dependent oxidative reactions, have been found in human plasma and are thought to regulate physiological functions in multiple cell types. Of significance, we have shown that both OA-NO2 and LNO2 are the endogenous PPAR3 ligands. Also, our preliminary studies have documented for the first time that intracerebroventricular administration of OA-NO2 can reduce cerebral infarct volume and edema in mice after 24h of middle cerebral artery (MCA) occlusion. Moreover, we have found that OA-NO2 can bind to AT1R and inhibit its signaling in vascular smooth muscle cells (VSMCs). Furthermore, we have also found that OA-NO2 can inhibit inflammatory reaction in cerebral VSMCs and cerebral vascular endothelial cells (CECs) after exposure to Oxygen Glucose Deprivation (OGD). These findings suggest that nitroalkenes play a critical protective role in ischemic brain damage. In this proposal, we will test the central hypothesis that nitroalkenes (e.g. OA-NO2) may inhibit cerebral ischemia-induced vascular inflammation to exert neuronal protective effects by inhibition of the AT1R signaling pathway and activation of PPAR3-dependent cascade. Specifically, we will define 1) that OA-NO2 inhibits OGD-induced inflammation in cerebral vascular cells via AT1R and PPAR3 signaling pathways; 2) that vascular- selective activation of PPAR3 contributes to the neuronal protection of OA-NO2 in ischemic stroke; 3) that vascular-selective inhibition of AT1R signaling contributes to the neuronal protection of OA-NO2 in ischemic stroke. It is anticipated that elucidating the mechanism of OA-NO2-mediated brain protection in cerebral ischemia will lead to a better understanding of endogenous signaling actions of nitroalkenes in ischemic stroke and will set strong basis for new perspectives on rational drug design and development of nitroalkene derivatives for the treatment of stroke.