Nitroalkene-Mediated Vascular Protection and Ischemic Stroke

描述（由申请人提供）：缺血性卒中由短暂或永久性局部脑血流量减少引起，特征为一系列细胞紊乱。中风的死亡率为30%，是美国第三大死亡原因和成人残疾的主要原因。不幸的是，有效治疗的发展受到缺血后不可逆脑损伤快速发展的严重限制。近年来，越来越多的研究表明过氧化物酶体增殖物激活受体3（PPAR 3）和血管紧张素II（Ang II）1型受体（AT 1 R）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（LNO 2），在一氧化氮（NO）依赖性氧化反应中形成的硝基烯烃，已被发现在人体血浆中，并被认为是调节多种细胞类型的生理功能。重要的是，我们已经表明OA-NO2和LNO 2都是内源性PPAR 3配体。此外，我们的初步研究首次证明，脑室内给予OA-NO2可以减少大脑中动脉（MCA）闭塞24小时后小鼠的脑梗死体积和水肿。此外，我们发现OA-NO2可以与血管平滑肌细胞（VSMCs）中的AT 1 R结合并抑制其信号转导。此外，我们还发现OA-NO2可以抑制OGD后脑VSMCs和脑血管内皮细胞（CEC）的炎症反应。这些发现表明，硝基烯烃在缺血性脑损伤中起着关键的保护作用。在本研究中，我们将验证硝基烯烃类化合物（如OA-NO2）可能通过抑制AT 1 R信号通路和激活PPAR 3依赖性级联反应来抑制脑缺血诱导的血管炎症，从而发挥神经元保护作用的中心假设。具体而言，我们将定义1）OA-NO2通过AT 1 R和PPAR 3信号传导途径抑制脑血管细胞中OGD诱导的炎症; 2）PPAR 3的血管选择性激活有助于缺血性中风中OA-NO2的神经元保护; 3）AT 1 R信号传导的血管选择性抑制有助于缺血性中风中OA-NO2的神经元保护。阐明OA-NO2介导的脑缺血保护作用机制，将有助于深入了解硝基烯烃类化合物在缺血性脑卒中中的内源性信号传导作用，为合理设计和开发治疗脑卒中的硝基烯烃类化合物奠定基础。

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.