Troponin T and Vascular Endothelial Cell Dysfunction in Aging

项目摘要 内皮细胞的衰老相关改变在许多慢性人类肿瘤的发病机制中起着重要作用， 疾病，包括但不限于心血管疾病、肌肉减少症、阿尔茨海默病和肿瘤 进展/转移。通过阐明衰老相关内皮细胞的分子机制， 功能障碍，可以揭示新的途径，用于设计新的诊断生物标志物和鉴定 可能的治疗靶点。不同类型的最新证据 基因芯片、流行病学和培养的肿瘤内皮细胞的研究强烈表明， 心肌肌钙蛋白T（cTnT）在血管内皮细胞中表达。cTnT是一种已知的A激酶锚定蛋白， 蛋白我们最近报道它调节蛋白激酶A（PKA）调节亚基RI和RII 老年小鼠骨骼肌神经肌肉接头的差异，表明年龄和组织类型- cTnT依赖PKA调节。激酶锚定蛋白也与蛋白激酶C（PKC）相互作用。 PKA和PKC均参与caspase的激活，这些分子在调节caspase的表达中起着关键作用。 内皮屏障完整性。后者对于维持水分和蛋白质之间的平衡至关重要， 血管内和血管外隔室。内皮屏障完整性和功能受损（对于 例如，血脑屏障的通透性增加）已经涉及到的发生和/或进展 包括阿尔茨海默氏症在内的多种病理状况和疾病。我们的初步数据 显示老年小鼠血管内皮细胞中cTnT的表达高于年轻小鼠， 与更高水平的caspase-3激活有关。鉴于所有这些证据，我们的主要假设是 （a）血管内皮细胞中cTnT的表达随着年龄的增长而增加，（B）这种变化导致 通过改变PKA/PKC-半胱天冬酶信号传导损害内皮屏障完整性。在这个探索性的R21中， 在新研究者领导的应用程序中，我们提出了3个具体目标来验证我们的假设。目标1： 确定cTnT的年龄依赖性变化是否与脑中PKA、PKC和caspase的改变相关 血管内皮细胞目的2旨在确定cTnT-PKA/PKC-caspase信号通路是否调节血管内皮细胞的增殖和分化， 内皮细胞死亡。目的3：探讨脑血管内皮细胞中cTnT表达水平的调控 内皮细胞在体内可影响老年小鼠血脑屏障的完整性。该项目由一名 多学科团队，将是第一个定义cTnT在血管内皮细胞老化中的作用。发现可能 有助于深入了解阿尔茨海默病的新分子机制和可能的治疗方案 和其他与衰老有关的慢性疾病。

Project Summary Aging-related alterations of endothelial cells play a central role in the pathogenesis of many chronic human diseases, including but not limited to cardiovascular diseases, sarcopenia, Alzheimer's disease, and tumor progress/metastasis. By elucidating the molecular mechanisms underlying aging-related endothelial dysfunction, new pathways could be revealed for designing novel diagnostic biomarkers and identifying possible therapeutic targets for those common and devastating diseases. Recent evidence from different types of studies – gene microarray, epidemiologic, and cultured tumor endothelial cells – strongly indicates that cardiac troponin T (cTnT) is expressed in vascular endothelial cells. cTnT is a known A kinase anchoring protein. We reported recently that it regulates the protein kinase A (PKA) regulatory subunit RI and RII differentially at neuromuscular junction in skeletal muscle of old mouse, indicating and age and tissue type- dependent PKA regulation by cTnT. A kinase anchoring proteins also interact with protein kinase C (PKC). Both PKA and PKC are involved in caspase activation, and these molecules play critical roles in regulating endothelial barrier integrity. The latter is critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier integrity and function (for instance, increased permeability of blood-brain barrier) has been implicated in the genesis and/or progression of a variety of pathological conditions and diseases, including Alzheimer's disease. Our preliminary data revealed that cTnT expression in vascular endothelial cells is higher in old mice than the young, and is associated with higher levels of caspase-3 activation. Given all these evidence, our central hypotheses are that (a) cTnT expression in vascular endothelial cells increases with aging, and (b) this change leads to impaired endothelial barrier integrity through altering PKA/PKC-caspase signaling. In this exploratory R21 application, led by a New Investigator, we propose 3 Specific Aims to test our hypothesis. Aim 1 seeks to determine if age-dependent change in cTnT is associated with altered PKA, PKC, and caspases in brain vascular endothelial cells. Aim 2 seeks to determine if cTnT-PKA/PKC-caspase signaling regulates vascular endothelial cell death. Aim 3 seeks to determine if manipulation of cTnT expression level in brain vascular endothelial cells in vivo can affect integrity of the blood-brain barrier in old mice. This project, conducted by a multidisciplinary team, will be the first to define a role for cTnT in vascular endothelial cell aging. Findings may help provide insights into new molecular mechanisms and possible therapeutic options for Alzheimer's disease and other aging-related chronic diseases.