TRP channels in the regulation of vascular tone

血管内环境的稳定主要依赖于内皮细胞释放的血管扩张因子。最 这些因素中的突出的是一氧化氮（NO），其是内皮功能的主要晴雨表， 在包括冠状动脉疾病（CAD）在内的广泛疾病中受损。在人体冠状动脉和 脂肪微循环，我们已经证明了一个新的过程，其中损失NO依赖的流量介导的 CAD受试者的血管扩张（FMD）通过从血管扩张中产生过氧化氢（H2 O2）来补偿。 内皮线粒体和随后的H2 O2依赖性扩张。虽然两者都是血管扩张剂，但H2 O2， 与NO相反，通常促进细胞活化，炎症和动脉粥样硬化，因此了解 负责从NO到H2 O2的这种转变的机制可能是开发新策略的关键， 冠心病患者的内皮功能。这个项目的总体目标是阐明信号机制 在CAD期间调节血管扩张剂从NO到H2 O2的转换。在上一个周期调查结果的基础上， 该提案旨在确定细胞内途径，负责以前不受重视的增益， 内皮细胞瞬时受体电位香草酸4（TRPV 4）通道的功能及其对血管舒张的作用 在CAD中切换。我们将测试中心假设，剪切敏感磷脂酶A2衍生的协同作用， 花生四烯酸和NADPH氧化酶信号促进TRPV 4活化和随后的H2 O2依赖性 扩张，同时交叉抑制CAD小动脉中的NO依赖性扩张。此外，NADPH氧化酶作为新的老化- CAD相关的上游调节器在启动转换中起关键作用。该应用程序带来了 结合血管舒缩调节、人体微循环和离子通道结构生物学方面的专业知识， 新的分子机制和相互作用，调节血管扩张开关在CAD。具体目标：（1）我们 将确定TRPV 4激活和小动脉扩张的分子机制;（2）我们将 确定NADPH氧化酶如何调节TRPV 4活化和从NO转化为H2 O2作为介体， CAD小动脉中的FMD。研究将在新鲜分离的人小动脉和内皮细胞上进行， 以及体内动物模型，使用多方面的方法，包括分离的血管反应性，Ca 2 + 成像、膜片钳电生理学、质谱、RNA-Seq、诱变和离子通道 分子模拟意义：我们提出的研究将提供深入了解的基本机制 调节健康和疾病中的人体微血管功能，并可能影响我们对冠状动脉疾病的治疗方法。 微血管功能障碍与CAD和各种其他血管病变。

Vascular homeostasis is critically dependent upon vasodilator factors released from the endothelium. The most prominent of these factors is nitric oxide (NO), which is the main barometer of endothelial function and becomes impaired in a broad range of diseases including coronary artery disease (CAD). In the human coronary and adipose microcirculation, we have demonstrated a novel process where loss of NO-dependent flow-mediated dilation (FMD) in subjects with CAD is compensated by the production of hydrogen peroxide (H2O2) from endothelial mitochondria and subsequent H2O2-dependent dilation. Although both are vasodilators, H2O2, in opposition to NO, generally promotes cell activation, inflammation, and atherosclerosis, and thus understanding mechanisms responsible for this transition from NO to H2O2 may be key to developing novel strategies to improve endothelial function in patients with CAD. The overall goal of this project is to elucidate the signaling mechanisms that regulate the vasodilator switch from NO to H2O2 during CAD. Building on findings from the last cycle, this proposal is designed to determine intracellular pathways responsible for a previously unappreciated gain of function of endothelial transient receptor potential vanilloid 4 (TRPV4) channels and its contribution to vasodilator switch in CAD. We will test the central hypothesis that a synergy of shear-sensitive phospholipase A2-derived arachidonic acid and NADPH oxidase signaling promotes TRPV4 activation and subsequent H2O2-dependent dilation while cross-inhibiting NO-dependent dilation in CAD arterioles. Further, NADPH oxidases as novel aging- and CAD-associated upstream regulators play a critical role in initiating the switch. This application brings together expertise in vasomotion regulation, human microcirculation, and ion channel structural biology to identify novel molecular mechanisms and interactions that regulate vasodilator switch during CAD. Specific Aims: (1) we will determine the molecular mechanism of TRPV4 activation and arteriolar dilation by flow; and (2) we will determine how NADPH oxidases regulate TRPV4 activation and conversion from NO to H2O2 as mediator of FMD in CAD arterioles. Studies will be conducted on freshly isolated human arterioles and endothelial cells as well as in vivo animal models, using a multifaceted approach incorporating isolated vessel reactivity, Ca2+ imaging, patch-clamping electrophysiology, mass spectrometry, RNA-Seq, mutagenesis, and ion channel molecular modeling. Significance: our proposed studies will provide insight into fundamental mechanisms regulating human microvascular function in health and disease and potentially impact our approach to coronary microvascular dysfunction associated with CAD and a variety of other vascular pathologies.