ESTROGEN REGULATION OF SMOOTH MUSCLE BKCA CHANNELS

雌激素对平滑肌 BKCA 通道的调节

• 批准号: 6719855
• 负责人: Kathleen Dunlap
• 金额: $ 25.07万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6719855
• 关键词: Xenopus oocyte; biological signal transduction; cGMP dependent protein kinase; calcium ion; electrophysiology; enzyme activity; estrogen receptors; estrogens; gene expression; gene targeting; genetically modified animals; guanylate cyclase; hormone regulation /control mechanism; ion channel blocker; laboratory mouse; myocardial ischemia /hypoxia; nitric oxide synthase; phosphorylation; potassium channel; protein structure function; tissue /cell culture; transcription factor; vascular endothelium; vascular smooth muscle; vasodilatation

Estrogen protects the cardiovascular system from injury by complex mechanisms that have both short- and long-term components. Longer- term estrogen actions occurs following hours of estrogen exposure and is mediated by estrogen receptors acting in the nucleus as transcription factors for growth-related genes. The rapid effects of estrogen, by contrast, occurs in a seconds-to-minutes time frame and do not require gene transcription. Project 5 of the SCOR application addresses the molecular mechanisms underlying one of the most important of these rapid effects-vasodilation. The signaling pathways underlying this non- genomic action of estrogen are incompletely understood but new data support they involve the action of nitric oxide synthase in vascular cells, elevation of nitric oxide, stimulation of vascular smooth muscle cell soluble guanylyl cyclase, and substrate phosphorylation by cGMP- dependent protein kinase (PKG). Although the key substrate(s) for PKG is unknown, new data support one likely possibility is the smooth muscle large conductance Ca2+-activated K+ (BKCa) channel. Blockade of BKCa channels in vascular rings significantly reduces estrogen-induced vasodilation, demonstrating the central role that BKCa channels in vascular rings significantly reduces estrogen-induced vasodilation, demonstrating the central role that BKCa channels play in the acute physiological response to estrogen. Experiments in Aim 1 will use BKCa channels in vascular rings significantly reduces estrogen-induced vasodilation, demonstrating the central role that BKCa channels play in the acute physiological response to estrogen. Experiments in Aim 1 will use BKCa channel activity recorded from single smooth muscle cells dissociated from mouse aorta as an assay for characterizing upstream elements in the estrogen signaling pathway that targets BKCa channels. Experiments will assess the relative contributions of endothelial and smooth muscle cells, the types of estrogen receptor involved, and the requirement for nitric oxide synthase activation. Experiments in Aim 2 will focus on the molecular mechanism by which BKCa channel activity is regulated by estrogen. We will identify the molecular variants of BKCa channel activity is regulated by estrogen. We will identify the molecular variants. variants of BKCa channels that are expressed in smooth muscles cells from mouse aorta and study the recombinant channels expressed heterologously in order to test the hypothesis that estrogen brings about BKCa channel activation through a direct PKG-dependent phosphorylation of the channel protein. Such information is essential to further understand the protective effects of estrogen on vascular tissue and may form the basis for development of new therapies for cardiovascular disease.

雌激素可保护心血管系统免受短期和长期成分的复杂机制的伤害。长期雌激素的作用发生在雌激素暴露小时后发生，并由作用在细胞核中作为生长相关基因转录因子的雌激素受体介导。相比之下，雌激素的快速作用发生在几秒钟到一分钟的时间范围内，不需要基因转录。 SCOR应用程序的项目5解决了这些快速效应 - 舒张中最重要的分子机制。雌激素的这种非基因组作用的信号传导途径尚不完全理解，但是新数据支持它们涉及一氧化氧化物合酶在血管细胞中的作用，一氧化氮的升高，刺激血管平滑肌细胞细胞的刺激，抑制胰鸟类环鸟乳凝酶环鸟叶糖环酶，以及CGMP-protents Protents protents protent kiteins kinasase（Pkeg）Kinasase（Pkeg）Kinase（Pken）Kinase（Pken）Kinase（Pkeg）Kinase（Pken）。尽管PKG的关键底物尚不清楚，但新的数据支持一种可能性是平滑肌大电导Ca2+激活的K+（BKCA）通道。血管环中BKCA通道的阻塞可显着减少雌激素诱导的血管舒张，这表明BKCA通道在血管环中显着降低了雌激素诱导的血管舒张，这表明BKCA通道在对雌激素的急性物理学反应中起着BKCA通道的中心作用。 AIM 1中的实验将在血管环中使用BKCA通道可显着降低雌激素诱导的血管舒张，这表明BKCA通道在对雌激素的急性生理反应中所起的核心作用。 AIM 1中的实验将使用从小鼠主动脉解离的单个平滑肌细胞中记录的BKCA通道活性，以表征针对BKCA通道的雌激素信号通路中上游元件。实验将评估内皮细胞和平滑肌细胞的相对贡献，所涉及的雌激素受体的类型以及一氧化氮合酶激活的需求。 AIM 2中的实验将集中在BKCA通道活性受雌激素调节的分子机制上。我们将确定BKCA通道活性的分子变体受雌激素调节。我们将确定分子变体。 BKCA通道的变体来自小鼠主动脉的平滑肌细胞中，并研究重组通道异源表达的重组通道，以检验雌激素通过通道蛋白的直接PKG依赖性磷酸化引起BKCA通道激活的假设。这种信息对于进一步了解雌激素对血管组织的保护作用至关重要，并可能构成开发新疗法的心血管疾病的基础。