MicroRNA-29b and Endothelial Function

 描述（由申请人提供）：微血管内皮功能障碍先于血管疾病的发展，并预示着未来的不良血管事件。内皮功能障碍很容易通过一氧化氮（NO）生物利用度的特征性损失来识别，这是由多种蛋白质和分子途径的失调引起的。然而，我们缺乏关于这些蛋白质和分子如何协调调节的重要知识。已经证明microRNA通过协同靶向参与生理或疾病过程的多个基因而充当“主”调节剂。然而，microRNA在内皮功能障碍中的作用，特别是在糖尿病的背景下，仍然在很大程度上未被探索。 我们已经获得的初步数据表明，血管miR-29 b的稳态水平对于维持人类和动物模型中正常的微血管NO生物利用度和内皮依赖性血管舒张至关重要。相反，在2型糖尿病（一种以降低的微血管NO生物利用度和微血管发病率为特征的疾病）中，miR-29 b可以恢复NO生物利用度和内皮依赖性血管舒张。MiR-29 b对NO生物利用度的影响似乎是由于其对几个基因的协调作用，这些基因在多个调节水平上改变NO生物利用度。 在本申请中，我们提出研究miR-29 b在健康和2型糖尿病中的微血管内皮依赖性血管舒张和NO生物利用度中的新作用，并鉴定介导miR-29 b的这些作用的机制。拟议的项目将采用一种高度翻译的方法，将新开发的基因敲除大鼠模型的功能研究与从表型良好的志愿者中获得的完整人类血管的研究相结合。我们还将采用新开发的方法来鉴定参与miR-29 b作用的靶基因和分子通路。具体而言，我们将检验以下假设：内源性miR-29 b对于维持健康人类和动物的阻力血管中正常内皮依赖性血管舒张和NO生物利用度至关重要。目的2研究将验证miR-29 b可以恢复T2 DM患者和db/db小鼠阻力血管中的内皮依赖性血管舒张和NO生物利用度的假设。miR-29 b在内皮依赖性血管舒张和NO生物利用度中作用的分子机制将在目标3中进行检查。 这项研究将由一个经验丰富的研究人员团队进行，由一名医生科学家和一名基础科学家领导，他们拥有非常适合拟议项目的互补专业知识。该项目的成功完成将揭示调节内皮功能的新机制，并证明其临床意义。

 DESCRIPTION (provided by applicant): Microvascular endothelial dysfunction precedes the development of vascular disease and portends future adverse vascular events. Endothelial dysfunction is readily identified by a characteristic loss of nitric oxide (NO) bioavailability, whch results from the dysregulation of a wide variety of proteins and molecular pathways. However, we lack important knowledge of how these proteins and molecules are coordinately regulated. MicroRNAs have been demonstrated to act as "master" regulators of physiological or disease processes by coordinately targeting multiple genes involved in the process. However, the role of microRNAs in endothelial dysfunction, especially in the context of diabetes, remains largely unexplored. We have obtained preliminary data suggesting a homeostatic level of vascular miR-29b is critical for the maintenance of normal microvascular NO bioavailability and endothelium-dependent vasodilation in humans and animal models. Conversely, in type 2 diabetes mellitus, a disease typified by reduced microvascular NO bioavailability and microvascular morbidity, miR-29b could restore NO bioavailability and endothelium- dependent vasodilation. MiR-29b's impact on NO bioavailability appears to arise from its coordinated effects on several genes that alter NO bioavailability at multiple levels of regulation. We propose in this application to investigate the novel role of miR-29b in microvascular endothelium- dependent vasodilation and NO bioavailability in health and in type 2 diabetes and identify the mechanisms mediating these effects of miR-29b. The proposed project will employ a highly translational approach that combines functional studies of a newly developed knockout rat model with studies of intact human vessels obtained from well-phenotyped volunteers. We will also employ newly developed methods for identifying target genes and molecular pathways involved in the effect of miR-29b. Specifically, we will test the hypothesis that endogenous miR-29b is critical to maintaining normal endothelium-dependent vasodilation and NO bioavailability in resistance vessels in healthy humans and animals in Aim 1. Aim 2 studies will test the hypothesis that miR-29b can restore endothelium-dependent vasodilation and NO bioavailability in resistance vessels from T2DM patients and db/db mice. The molecular mechanisms underlying the role of miR-29b in endothelium-dependent vasodilation and NO bioavailability will be examined in Aim 3. The study will be carried out by a team of experienced researchers led by a physician scientist and a basic scientist who possess complementary expertise ideally suited for the proposed project. Successful completion of the project will reveal novel mechanisms regulating endothelial function and demonstrate their clinical relevance.