Transglutaminase 2 S-Nitrosylation: Role in Age-Related Vascular Stiffness

转谷氨酰胺酶 2 S-亚硝基化：在年龄相关血管僵硬中的作用

基本信息

批准号：
8307888
负责人：
DAN E BERKOWITZ
金额：
$ 39.41万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-20 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8307888
关键词：
Age Aging Animal Model Aorta Arteries Autopsy Biological Availability Blood Pressure Blood Vessels Buffers Cardiovascular Diseases Cardiovascular system Cell model Cell surface Characteristics Collagen Cystamine Cysteine Data Elastin Elderly Elements Endothelial Cells Endothelium Enzyme Inhibition Enzymes Equilibrium Exercise Extracellular Matrix Extracellular Matrix Proteins Fibroblasts Fracture Grant Heart Human Hypertension Inbred F344 Rats Isolated systolic hypertension Lead Location Measurement Measures Mediating Molecular Morbidity - disease rate Mus Myocardial Infarction NG-Nitroarginine Methyl Ester NOS3 gene Oxidation-Reduction Pathway interactions Perfusion Physiologic pulse Physiological Post-Translational Protein Processing Property Proteins Rattus Reactive Oxygen Species Regulation Risk Risk Factors Role SKIL gene Signal Transduction Silastic Smooth Muscle Myocytes Stroke System Tissues Transglutaminases Up-Regulation Vascular Endothelial Cell Vascular Endothelium Vascular Smooth Muscle age effect age related blood pump crosslink in vivo inhibitor/antagonist mortality pressure protein protein interaction public health relevance research study scaffold shear stress transcription factor transglutaminase 2

项目摘要

DESCRIPTION (provided by applicant): Vascular stiffness has been clearly established as a risk factor for cardiovascular disease, and is an independent predictor of cardiovascular morbidity and mortality. Aging is associated with increased vascular stiffness and isolated systolic hypertension, which results from alterations in the properties of all elements of the vascular wall including endothelium, vascular smooth muscle, and matrix. Although both dynamic (alterations in endothelial function and effects on vascular smooth contractility), as well as structural (eg. fracturing of elastin) have been described in aging, molecular mechanisms underlying age-related vascular stiffness remain poorly understood. Thus targeted therapy remains elusive. Tissue transglutaminase (TG2, tTG), expressed in vascular endothelial, smooth muscle cells, and fibroblasts, enzymatically form cross-links between extracellular matrix proteins, and may contribute to this pathobiology. Ca2+dependent activation of TG2 is dependent on its externalization to the cell surface. Recently, it has been demonstrated that S- nitrosylation, a redox-sensitive post-translational modification of cysteine residues, leads to TG2 enzyme inhibition. In Preliminary Data, we demonstrate that TG2 is S-nitrosylated in cellular models and that this leads to decreased cell-surface localization and decreased cross-linking activity. Furthermore, using TG2-/- mice, we show that TG2 is the primary TGase mediating stiffness of conduit arteries, and that it is regulated by endothelium-derived NO. We further demonstrate that in aging rat and human aorta, TG2 activity is increased, and it's S-nitrosylation is decreased despite unchanged TG2 abundance. Finally, inhibition of TG in old rats reduces vascular stiffness. It is now well established that NO bioavailability is diminished and reactive oxygen species (ROS) are increased in aging. Given this change in the nitroso-redox balance, we hypothesize that aging is associated with decreased TG2 S-nitrosylation and therefore, increased externalization and increased matrix cross-linking activity and TG2-dependent downstream signaling. Together, these result in increased vessel stiffness, and ultimately impaired vascular function, a hallmark of aging. In this grant, we propose to determine the role of NO in the regulation of TG2 location, activity and downstream signaling, and determine whether this enzyme is a critical target in age-related vascular stiffness. We will use a hierarchical approach including endothelial cells, vascular tissue from young and old Fischer 344 rats and TG2-/- and NOS3-/- mice, and invasive and non-invasive measures of vascular characteristics in these animal models. The following are the specific aims: 1) To determine the role of endothelium-dependent NO in the of regulation of TG2 subcellular distribution and activity. 2) To determine the role of TGF2 in downstream TG2 mediated vascular signaling. 3) To determine the role of TG2 and its regulation by NO in age-related vascular stiffness in animal models using sophisticated measures of vascular properties in vivo. 4) To determine TG2 activity in the aorta of aging humans. PUBLIC HEALTH RELEVANCE: As we age, our blood vessels become stiffer because of the changes that occur in all wall of the large blood vessels. When the aorta stiffens it is less able to buffer the pulse created by pumping of blood into it from the heart leading high blood pressure in the elderly which is very difficult to treat. This vascular stiffening and high blood pressure is associated with an increase risk of heart attack and stroke as we age. We have identified an enzyme that creates "bridges" or "scaffolds" between other proteins in the vessel wall contributing to its stiffening, and plan to study its mechanism of regulation, thereby helping us to determine whether blocking the enzyme might be important in treating age-related high blood pressure.

描述（由申请人提供）：血管僵硬度已被明确确定为心血管疾病的危险因素，并且是心血管发病率和死亡率的独立预测因子。衰老与血管硬度增加和孤立性收缩期高血压有关，这是由于血管壁所有元素（包括内皮、血管平滑肌和基质）特性的改变所致。尽管衰老过程中的动态（内皮功能的改变和对血管平滑收缩性的影响）以及结构（例如弹性蛋白的断裂）都已被描述，但与年龄相关的血管僵硬的分子机制仍然知之甚少。因此，靶向治疗仍然难以实现。组织转谷氨酰胺酶（TG2、tTG）在血管内皮细胞、平滑肌细胞和成纤维细胞中表达，通过酶促方式在细胞外基质蛋白之间形成交联，并可能促成这种病理生物学。 TG2 的 Ca2+ 依赖性激活取决于其在细胞表面的外化。最近，已经证明，S-亚硝基化（半胱氨酸残基的氧化还原敏感翻译后修饰）会导致 TG2 酶抑制。在初步数据中，我们证明 TG2 在细胞模型中被 S-亚硝基化，这会导致细胞表面定位减少和交联活性降低。此外，使用 TG2-/- 小鼠，我们发现 TG2 是介导导管动脉僵硬度的主要 TGase，并且它受到内皮源性 NO 的调节。我们进一步证明，在衰老大鼠和人类主动脉中，TG2 活性增加，尽管 TG2 丰度不变，但其 S-亚硝基化水平降低。最后，抑制老年大鼠的 TG 可降低血管僵硬度。现在已经证实，随着年龄的增长，NO 的生物利用度会降低，活性氧 (ROS) 会增加。鉴于亚硝基氧化还原平衡的这种变化，我们假设衰老与 TG2 S-亚硝基化减少有关，因此，外化作用增加，基质交联活性增加，以及 TG2 依赖性下游信号传导增加。这些因素共同导致血管硬度增加，并最终损害血管功能，这是衰老的标志。在这项资助中，我们建议确定 NO 在 TG2 位置、活性和下游信号传导调节中的作用，并确定该酶是否是与年龄相关的血管僵硬度的关键靶点。我们将使用分层方法，包括来自年轻和年老 Fischer 344 大鼠以及 TG2-/- 和 NOS3-/- 小鼠的内皮细胞、血管组织，以及这些动物模型中血管特征的侵入性和非侵入性测量。具体目的如下： 1）确定内皮依赖性NO在TG2亚细胞分布和活性调节中的作用。 2)确定TGF2在下游TG2介导的血管信号传导中的作用。 3) 使用体内血管特性的复杂测量来确定TG2的作用及其在动物模型中由NO调节的与年龄相关的血管僵硬度。 4) 测定老年人主动脉中的TG2活性。公共健康相关性：随着年龄的增长，由于大血管的所有壁发生变化，我们的血管变得更僵硬。当主动脉变硬时，它就无法缓冲从心脏泵入血液所产生的脉搏，从而导致老年人患高血压，而这种情况很难治疗。随着年龄的增长，血管硬化和高血压与心脏病和中风的风险增加有关。我们已经鉴定出一种酶，可以在血管壁中的其他蛋白质之间建立“桥梁”或“支架”，从而导致血管壁变硬，并计划研究其调节机制，从而帮助我们确定阻断该酶对于治疗年龄是否重要相关的高血压。