Wnt signaling control of vascular phenotype in obesity

项目摘要/摘要 目前的方案代表了临床以患者为中心和实验小鼠相结合的方案 一项旨在研究肥胖患者血管功能障碍机制的研究。肥胖症有 发展成为我们最关键的医疗保健问题之一，因为69%的美国人口目前 超重或肥胖。脂肪组织功能障碍、炎症和胰岛素抵抗是必不可少的。 将肥胖与心血管疾病的发病机制联系起来的特征。我们的初步数据 证明一种独特的促炎Wnt信号通路显著上调，该信号通路可能在 在肥胖症的血管功能障碍机制中起主要作用。在这份提案中，我们将研究 Wnt信号在完整血管微血管内皮细胞功能调节中的作用 从活体受试者获取的分离内皮细胞。我们将利用多学科方法， 临床和基础科学家之间的互补专业知识，以确定病理生理学特征 功能失调的Wnt5a信号转导系统的作用。在目标1中，我们将描述特定于仓库的机制 人脂肪组织小动脉血管内皮细胞功能障碍的电视显微镜观察 择期手术中从皮下和内脏脂肪隔间分离的血管 在150名肥胖者和50名年龄和性别匹配的瘦身受试者中。我们将描述血管的特征 表型与Wnt信号的关系，并验证Wnt5a过度激活介导的假说 信号是导致血管功能障碍的主要调节特征。在目标2和目标3中，具体 WNT5a和转化生长因子β途径的药理和生物抑制剂将用于 来自Aim 1的小动脉和内皮细胞，以检验WNT5a拮抗作用逆转的假设 血管功能障碍，部分是通过调节脂肪组织中的内源性MT的能力，并寻求 确定肥胖症的新调节剂和治疗靶点。以证实这些发现在遗传学上 模型，我们将探索EndoMT以及小鼠的血管和代谢表型 被设计成有条件地去除或在髓系细胞中过度表达WNT5a。在目标4中，研究 救命减肥手术后6个月内皮细胞表型将重复 从目标1开始对相同的150名肥胖受试者进行干预，以检查标记体重的影响 AIMS 2和3中发现的小动脉反应和相关的Wnt分子通路的减少。 整个项目结合了细胞信号和使用初级组织的全血管生理学的研究 来自严重肥胖的人，目前临床上几乎没有血管数据。我们的建议 可能确定Wnt5a-Sfrp5轴是一种新的血管生物学调节器，并可能导致 确定抗击肥胖引起的心血管疾病的新目标和新方法。

Project Summary/Abstract The current proposal represents a combined clinical patient-oriented and experimental murine investigation which seeks to examine mechanisms of vascular dysfunction in obesity. Obesity has developed into one of our most critical health care problems as 69% of the US population is currently overweight or obese. Adipose tissue dysfunction, inflammation, and insulin resistance are essential hallmarks linking obesity to the pathogenesis of cardiovascular disease. Our preliminary data demonstrate marked up-regulation of a unique pro-inflammatory Wnt signaling pathway that may play a major role in mechanisms of vascular dysfunction in obesity. In this proposal, we will examine the role of Wnt signaling in the regulation of microvascular endothelial function in intact blood vessels and isolated endothelial cells acquired from living subjects. We will utilize a multidisciplinary approach and complementary expertise between clinical and basic scientists to characterize the pathophysiological role of dysfunctional Wnt5a signaling. In aim 1, we will characterize depot-specific mechanisms of vascular endothelial dysfunction in human adipose tissue arterioles using videomicroscopy of small vessels isolated from subcutaneous and visceral fat compartments during elective surgical procedures in 150 obese and 50 age- and gender-matched lean subjects. We will characterize vascular phenotypes in relation to Wnt signaling and test the hypothesis that over-activation of Wnt5a-mediated signaling is a dominant regulatory feature that leads to vascular dysfunction. In aims 2 and 3, specific pharmacological and biological inhibitors of the Wnt5a and TGFβ pathways will be employed using arterioles and endothelial cells from aim 1 to test the hypothesis that antagonism of Wnt5a reverses vascular dysfunction, in part through its ability to modulate EndoMT in adipose tissue, and seek to identify novel regulators and therapeutic targets in obesity. To corroborate these findings in genetic models, we will explore EndoMT and the vascular and metabolic phenotypes of mice that are engineered to conditionally ablate or overexpress Wnt5a in myeloid cells. In aim 4, studies of endothelial phenotyping will be repeated 6-months after life-saving bariatric weight loss surgical intervention in the same 150 obese subjects from aim 1 to examine the effects of marked weight reduction on arteriolar responses and relevant Wnt molecular pathways identified in aims 2 and 3. The overall project combines studies of cellular signaling and whole vessel physiology using primary tissues from severely obese individuals where clinically very little vascular data currently exist. Our proposal may identify the Wnt5a-Sfrp5 axis as a novel modulator of vascular biology and potentially lead to the identification of new targets and approaches to combat obesity-induced cardiovascular disease.