MiR-204 regulates type 1 IP3R/Ca2+ axis to control vascular smooth muscle cell contractility and blood pressure: Potential role of the gut microbiome

项目摘要 高血压是全世界最常见的心血管疾病。放松对血管的管制 血管平滑肌细胞(VSMC)收缩是高血压的最终共同途径。细胞内 钙(Ca~(2+))是VSMC收缩的触发因素和关键决定因素。血管平滑肌 细胞内钙离子浓度受细胞外钙离子内流和外流的严格调节 空间和细胞内储存物，最明显的是肌浆网。肌醇1，4，5- 三磷酸(IP3)通过其受体(IP3R)控制肌浆内钙的释放 网状结构进入细胞质。 高血压是一种多系统疾病。远距离内环境平衡机制的破坏 器官可以影响血管张力。举个例子，肠道中的细菌(肠道微生物群) 可以调节血压。血压正常的动物在移植时会变得高血压 来自高血压动物的肠道微生物区系，反之亦然。此外，中国的高血压 人类与肠道微生物多样性的特定变化有关，这为 前提是肠道微生物负荷和多样性的变化(生物失调)有助于 高血压的发病机制。我们的初步数据显示，小鼠的生物失调由 广谱抗生素导致血管高度收缩和相关 上调IP3R1的表达。此外，我们有证据表明广谱抗生素 下调微生物组敏感的microRNA miR-204在血管中的表达 肌肉细胞。此外，miR-204以IP3R1为靶点，miR-204全局缺失的小鼠 易患上高血压的。因此，我们假设miR-204是一个密钥 VSMC收缩调节因子及其在肠道微生物失调中的下调作用 高血压。 这项应用将研究miR-204在调节VSMC钙离子中的作用，并探索 它这样做的机制。它将在VSMC中使用miR-204和IP3R1缺失的小鼠， 以及最先进的方法来评估活动物细胞和血管中的钙离子流量。 使用这些独特的工具，并结合汇集的专业知识，它将确定miR-204是否可以控制 血压、VSMC钙动态平衡和VSMC收缩通过IP3R1。此外，它还将 开辟一条连接肠道微生物群和调节血管张力的道路，通过确定肠道是否 微生物失调破坏VSMC钙动态平衡，并通过 下调miR-204的表达。从这项工作中获得的信息将是对 高血压研究领域。

Project Summary Hypertension is the most prevalent cardiovascular disorder worldwide. Deregulation of vascular smooth muscle cell (VSMC) contraction is a final common pathway in hypertension. Intracellular calcium (Ca2+) is a trigger and key determinant of VSMC contraction. Vascular smooth muscle cytosolic Ca2+ concentration is tightly regulated by Ca2+ influx and efflux from the extracellular space and from intracellular stores, most notably the sarcoplasmic reticulum. Inositol 1,4,5- trisphosphate (IP3) through its receptors (IP3R) controls Ca2+ release form the sarcoplasmic reticulum into the cytoplasm. Hypertension is a multi-system disease. Disruption of homeostatic mechanisms in distant organs can affect vascular tone. As one example, bacteria that inhabit the gut (gut microbiome) can modulate blood pressure. Normotensive animals become hypertensive when transplanted with gut microbiota from hypertensive animals, and vice versa. Furthermore, hypertension in humans is associated with specific alterations in gut microbial diversity, lending credence to the premise that a change in gut microbial load and diversity (dysbiosis) contributes to the pathogenesis of hypertension. Our preliminary data shows that dysbiosis in mice caused by broad-spectrum antibiotics leads to hypercontractility of blood vessels and associated upregulation of IP3R1. In addition, we have evidence that broad-spectrum antibiotics downregulate expression of miR-204, a microbiome-sensitive microRNA, in vascular smooth muscle cells. Moreover, miR-204 targets IP3R1, and mice with global deletion of miR-204 are susceptible to developing hypertension. We therefore hypothesize that miR-204 is a key regulator of VSMC contractility, and its downregulation due to gut microbial dysbiosis promotes hypertension. This application will examine the role of miR-204 in regulating VSMC Ca2+ and explore the mechanisms by which it does so. It will use mice with deletion of miR-204 and IP3R1 in VSMC, and state-of-the-art methodologies to assess Ca2+ flux in cells and in vessels of live animals. Using these unique tools, and with the assembled expertise, it will determine if miR-204 controls blood pressure, VSMC Ca2+ homeostasis and VSMC contraction via IP3R1. In addition, it will blaze a trail connecting the gut microbiome and regulation of vascular tone, by determining if gut microbial dysbiosis disrupts VSMC Ca2+ homeostasis, and promotes hypertension through downregulation of miR-204. Information gained from this work will be a vertical advancement in the field of hypertension research.