ROLE OF MITOCHONDRIAL-PRODUCED ROS IN NEUROGENIC HYPERTENSION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 脑血管紧张素II(AngII)信号调节失调与心力衰竭和高血压等心血管疾病的发病机制有关。循环中血管紧张素Ⅱ水平的升高可通过作用于被称为脑室周围器官的特殊脑区而导致神经源性高血压的发生，这些脑区缺乏血脑屏障，并改变了中枢心血管输出，包括交感神经兴奋、血管加压素的释放和压力感受器反射的抑制。为了更好地了解血管紧张素转换酶在神经源性高血压发生发展中的中枢作用，并确定疾病的新的中枢治疗靶点，有必要研究血管紧张素转换酶在中枢神经系统(CNS)中的信号机制。在此之前，NADPH氧化酶产生的活性氧物种(ROS)被认为是中枢血管紧张素转换酶介导的心血管效应的重要信号中间产物。尽管NADPH氧化酶已被证明是ROS的关键来源，但包括线粒体在内的其他来源仍有待研究，线粒体是大多数细胞中ROS产生的主要部位。在此，我们提出了一系列体外分子生物学和生化研究以及体内综合心血管生理学实验，以验证线粒体产生的ROS在脑血管紧张素能信号转导中发挥基础作用，以及线粒体靶向抗氧化剂在中枢神经系统心血管控制区过表达可缓解神经源性高血压的新假说。使用中枢神经系统来源的原代神经元，以及Angii敏感的神经元细胞培养模型，我们将测量Angii刺激后线粒体中特定的ROS水平。此外，我们将使用腺病毒介导的线粒体靶向抗氧化剂的基因转移，以电生理技术检测线粒体产生的ROS对Angii在神经元中变时性作用的影响。最后，利用实验性血管紧张素Ⅱ依赖型神经源性高血压小鼠模型，我们将确定中枢神经系统线粒体产生的ROS在疾病发病机制中的作用。这些研究将为Angii的神经元内信号机制提供新的信息，并可能确定线粒体产生的ROS是神经源性高血压的重要治疗靶点。 平常人描述：心力衰竭和高血压是两种与大脑异常刺激有关的心血管疾病。脑细胞中产生的自由基和氧化剂称为神经元，已被证明与这些心血管疾病有关。这项研究的主要目标是使用抗氧化剂，这种抗氧化剂存在于特定细胞位置(线粒体)，以防止高血压的发展。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dysregulation of brain angiotensin II (AngII) signaling is implicated in the pathogenesis of cardiovascular diseases, including heart failure and hypertension. Increased circulating levels of AngII can lead to the development of neurogenic hypertension by acting on specialized brain regions known as circumventricular organs, which lack a blood-brain-barrier, and altering central cardiovascular outputs including sympathoexcitation, release of vasopressin, and dampening of baroreflexes. To better understand the central actions of AngII in the development of neurogenic hypertension and to identify novel, central therapeutic targets of the disease, it is essential to investigate the signaling mechanisms of AngII in the central nervous system (CNS). Previously, reactive oxygen species (ROS) generated by NADPH oxidase have been identified as important signaling intermediates in central AngII-mediated cardiovascular effects. Although NADPH oxidase has been shown to be a critical source of ROS, additional sources including mitochondria, which are the primary sites for ROS generation in most cells, have yet to be investigated. Herein, we propose a series of in vitro molecular biological and biochemical studies and in vivo integrative cardiovascular physiological experiments to test the novel hypothesis that mitochondrial-produced ROS play a fundamental role in brain angiotensinergic signaling, and that overexpression of mitochondrial-targeted antioxidants in CNS cardiovascular control regions ameliorates neurogenic hypertension. Using CNS-derived primary neurons, as well as an AngII-sensitive neuronal cell culture model we will measure ROS levels specifically in mitochondria following AngII stimulation. In addition, we will use adenoviral-mediated gene transfer of mitochondrial-targeted antioxidants to examine the effects of mitochondrial-produced ROS on the chronotropic action of AngII in neurons using electrophysiological techniques. Finally, using an experimental mouse model of AngII-dependent neurogenic hypertension we will determine the role of mitochondrial-produced ROS in the CNS in the pathogenesis of the disease. These studies will provide new information on the intra-neuronal signaling mechanisms of AngII, and may identify mitochondrial-produced ROS as important therapeutic targets in neurogenic hypertension. Lay Description: Heart failure and hypertension are two cardiovascular diseases associated with abnormal stimulation in the brain. Free radicals and oxidants produced in brain cells called neurons have been shown to be involved in these cardiovascular diseases. The primary goal of this study is to use antioxidants, which are found in a specific cellular location (mitochondria), to prevent the development of hypertension.