Wnt signaling control of vascular phenotype in obesity

项目概要/摘要 目前的建议代表了一个结合临床病人为导向和实验鼠 该研究旨在研究肥胖症中血管功能障碍的机制。肥胖已 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 肥胖与心血管疾病发病机制的联系。我们的初步数据 证明独特的促炎Wnt信号通路显着上调，该通路可能发挥作用 在肥胖症血管功能障碍机制中的重要作用。在本提案中，我们将研究 Wnt信号在完整血管微血管内皮功能调节中的作用， 从活体获得的分离的内皮细胞。我们将采用多学科方法， 临床和基础科学家之间的互补专业知识，以表征病理生理学 功能失调的Wnt 5a信号传导的作用。在目标1中，我们将描述 应用小血管显微镜观察人脂肪组织小动脉血管内皮功能障碍 在择期外科手术期间从皮下和内脏脂肪隔室分离的血管 在150名肥胖者和50名年龄和性别匹配的瘦受试者中。我们将描述血管 表型相关的Wnt信号和测试的假设，过度激活Wnt 5a介导的 信号传导是导致血管功能障碍的主要调节特征。在目标2和3中，具体 将使用Wnt 5a和TGFβ途径的药理学和生物学抑制剂， 目的1中的小动脉和内皮细胞，以检验Wnt 5a的拮抗作用逆转 血管功能障碍，部分通过其调节脂肪组织中EndoMT的能力，并寻求 确定肥胖症中新的调节剂和治疗靶点。为了证实这些发现， 模型，我们将探讨EndoMT和血管和代谢表型的小鼠， 工程化以在骨髓细胞中有条件地消除或过表达Wnt 5a。在目标4中， 在挽救生命的减肥手术后6个月将重复内皮表型分析 对目标1中相同的150名肥胖受试者进行干预， 目的2和3中鉴定的小动脉反应和相关Wnt分子途径的减少。的 整个项目结合了细胞信号和使用原代组织的整个血管生理学的研究 来自目前临床上几乎没有血管数据的严重肥胖个体。我们的建议 可能将Wnt 5a-Sfrp 5轴确定为血管生物学的新调节剂，并可能导致血管内皮细胞的凋亡。 确定防治肥胖引起的心血管疾病的新目标和方法。

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.