Role of Plasminogen Activator Inhibitor-1 in Vascular Smooth Muscle Cell Stiffening and Senescence

纤溶酶原激活剂抑制剂 1 在血管平滑肌细胞硬化和衰老中的作用

• 批准号: 10512042
• 负责人: William P Fay
• 金额: --
• 依托单位: HARRY S. TRUMAN MEMORIAL VA HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10512042
• 关键词: Actins; Adverse effects; Affect; Age; Aging; Alteplase; Arteries; Atherosclerosis; Atomic Force Microscopy; Biology; Blood; Blood Vessels; Blood coagulation; Blood flow; Cardiac; Cardiovascular Diseases; Cardiovascular Physiology; Cardiovascular system; Cell Adhesion; Cell Aging; Cell division; Cell physiology; Cells; Clinical; Clinical Trials; Cytoskeleton; Data; Disease; Drug Targeting; F-Actin; Fibrosis; Fluorescence Microscopy; Focal Adhesions; Generations; Genetic; Glycolysis; Goals; Heart; Heart failure; Hospitals; Hypertension; Inflammation; LDL-Receptor Related Protein 1; Link; Measurement; Mediating; Membrane Potentials; Missouri; Mitochondria; Mus; Myocardial Infarction; Myosin ATPase; Organ; Oxygen Consumption; Pathologic; Pathway interactions; Peripheral arterial disease; Pharmaceutical Preparations; Phenotype; Plasminogen Activator Inhibitor 1; Play; Production; Protease Inhibitor; Protein Secretion; Proteins; Proteolysis; Reactive Oxygen Species; Relaxation; Research; Role; Scientist; Serpin Superfamily; Signal Pathway; Smooth Muscle Myocytes; Stress Fibers; Stretching; Stroke; Testing; Translating; Trees; Universities; Urokinase; Vascular Diseases; Vascular Smooth Muscle; Veterans; Work; arterial stiffness; blood pressure regulation; blood pump; burden of illness; candidate identification; cell motility; clinically relevant; cofilin; conditional knockout; constriction; dalton; experience; experimental study; fatty acid oxidation; fitness; in vivo; inhibitor; innovation; medical schools; member; military veteran; mitochondrial membrane; mouse model; multidisciplinary; normal aging; novel; novel strategies; pharmacologic; prevent; recruit; respiratory; response; senescence; transcriptome sequencing; vascular inflammation

Vascular smooth muscle cells (SMCs) are present throughout the arterial tree and play a central role in cardiovascular physiology by regulating blood pressure and flow. Cardiovascular aging is characterized by pathologic changes in SMCs that contribute in a major way to high-burden diseases affecting US veterans, including hypertension, atherosclerosis, myocardial infarction, stroke, and peripheral artery disease. Two important phenotypic changes that occur in SMCs with aging are 1) stiffening, which produces hypertension and increases cardiac afterload, and 2) senescence, which is functionally defined as arrest of cell division and assumption of the senescence-associated secretory phenotype (SASP), a driver of vascular inflammation and fibrosis. Plasminogen activator inhibitor-1 (PAI-1), a member of the serpin superfamily of protease inhibitors, is the primary inhibitor of tissue-type plasminogen activator (t-PA) and urokinase (u-PA) and an important regulator of proteolysis and cell adhesion. PAI-1 expression increases with age and is associated with vascular fibrosis and generalized cell senescence. However, the specific effects of PAI-1 on SMC stiffening and senescence, as well as the mechanisms underlying them, are poorly understood. In preliminary studies involving pharmacologic and genetic modulation of PAI-1 expression in SMCs, we have shown that drug targeting of PAI-1 decreases SMC stiffness, assessed by atomic force microscopy (AFM), while also decreasing SMC cytoskeleton formation and enhancing activation of cofilin, which degrades filamentous (F)- actin. We also have demonstrated that PAI-1 promotes SMC senescence by a pathway involving the LDL receptor-related protein-1 (LRP1), while also dampening mitochondrial respiratory fitness, which is strongly linked to cell senescence. We have performed an RNA-sequencing analysis that has identified candidate signaling pathways mediating PAI-1’s effects on SMC stiffness and senescence. We also have generated mice with conditional knockout of PAI-1 in SMCs, which will enable us to study the significance of our findings in vivo. Based on our extensive preliminary data, we hypothesize that PAI-1 1) regulates SMC stiffness by controlling actin, myosin, and focal adhesion assembly in the cytoskeleton, and 2) promotes SMC senescence through adverse effects on mitochondrial energy substrate utilization and reactive oxygen species accrual. To test these hypotheses, we propose the following specific aims: 1) identify the intracellular signaling pathways by which PAI-1 regulates SMC stress fiber formation and stiffness, 2) determine the role of PAI-1 in regulating mitochondrial substrate utilization and reactive oxygen species accumulation in SMCs, probing underlying mechanisms, and 3) study the effects of pharmacologic and SMC-specific inhibition of PAI-1 on arterial stiffness and senescence in vivo. Several innovative strategies will be employed, including 1) AFM, 2) confocal fluorescence microscopy, 3) quantitative studies of PAI-1’s effects of F-actin, myosin, and focal adhesion assembly, 4) measurement of mitochondrial energy substrate utilization and membrane potential, and 5) novel murine models that enable quantification of the effects of systemic inhibition and SMC-specific deletion of PAI-1 on vascular stiffening and senescence in vivo. The experiments will be carried out by a highly experienced, multi-disciplinary team of scientists from the Truman VA Hospital, the University of Missouri School of Medicine, and the Dalton Cardiovascular Research Center. The significance of the proposed work is that it will 1) identify mechanisms by which PAI-1 and its pharmacological inhibition regulate key degenerative changes that occur in SMCs with aging, namely stiffening and senescence, and 2) translate these findings to the in vivo setting. The proposed experiments will yield important new information about the roles of PAI-1 and SMCs in vascular aging that are directly relevant to major cardiovascular diseases affecting the US veteran population. The studies also have great potential for transition to the clinical setting through the use of pharmacologic PAI-1 inhibitors.

血管平滑肌细胞 (SMC) 存在于整个动脉树中，在动脉血管生成过程中发挥着核心作用。 通过调节血压和流量来调节心血管生理学。心血管衰老的特点是 平滑肌细胞的病理变化在很大程度上导致了影响美国退伍军人的高负担疾病， 包括高血压、动脉粥样硬化、心肌梗塞、中风和外周动脉疾病。二 随着衰老，平滑肌细胞发生的重要表型变化是：1) 硬化，从而产生高血压 并增加心脏后负荷，2) 衰老，在功能上定义为细胞分裂和停止 衰老相关分泌表型（SASP）的假设，它是血管炎症的驱动因素 纤维化。纤溶酶原激活剂抑制剂-1 (PAI-1) 是蛋白酶抑制剂丝氨酸蛋白酶抑制剂超家族的成员， 组织型纤溶酶原激活剂 (t-PA) 和尿激酶 (u-PA) 的主要抑制剂，也是一种重要的 蛋白水解和细胞粘附的调节剂。 PAI-1 表达随着年龄的增长而增加，并与 血管纤维化和全身细胞衰老。然而，PAI-1 对 SMC 硬化的具体影响 人们对衰老及其背后的机制知之甚少。初步研究中 涉及 SMC 中 PAI-1 表达的药理学和遗传调节，我们已经证明药物 通过原子力显微镜 (AFM) 评估，PAI-1 的靶向降低了 SMC 硬度，同时还 减少 SMC 细胞骨架的形成并增强丝切蛋白的激活，从而降解丝状 (F)- 肌动蛋白。我们还证明，PAI-1 通过涉及 LDL 的途径促进 SMC 衰老 受体相关蛋白 1 (LRP1)，同时还会抑制线粒体呼吸适应性，这对线粒体呼吸适应性有很强的影响。 与细胞衰老有关。我们进行了 RNA 测序分析，确定了候选者 介导 PAI-1 对 SMC 硬度和衰老影响的信号通路。我们还生成了 在 SMC 中条件性敲除 PAI-1 的小鼠，这将使我们能够研究我们的发现的意义 体内。根据我们广泛的初步数据，我们假设 PAI-1 1) 通过以下方式调节 SMC 硬度： 控制细胞骨架中的肌动蛋白、肌球蛋白和粘着斑组装，2) 促进 SMC 衰老 通过对线粒体能量底物利用和活性氧累积的不利影响。到 为了检验这些假设，我们提出以下具体目标：1）确定细胞内信号通路 PAI-1通过其调节SMC应力纤维的形成和刚度，2）确定PAI-1在调节中的作用 SMC 中线粒体底物利用和活性氧积累，探究其背后的原因 机制，3) 研究 PAI-1 的药理学和 SMC 特异性抑制对动脉的影响 体内僵硬和衰老。将采用多种创新策略，包括 1) AFM，2) 共焦荧光显微镜，3) PAI-1 对 F-肌动蛋白、肌球蛋白和焦点的影响的定量研究 粘附组装，4)测量线粒体能量底物利用率和膜电位， 5) 新型小鼠模型，能够量化全身抑制和 SMC 特异性的影响 PAI-1 缺失对体内血管硬化和衰老的影响。实验将由 来自美国杜鲁门退伍军人医院、经验丰富的多学科科学家团队 密苏里医学院和道尔顿心血管研究中心。的意义 拟议的工作是 1) 确定 PAI-1 及其药理学抑制调节的机制 随着衰老，SMC 中发生的关键退行性变化，即硬化和衰老，以及 2) 转化 这些发现适用于体内环境。所提出的实验将产生关于 PAI-1 和 SMC 在血管老化中的作用与影响主要心血管疾病直接相关 美国退伍军人人口。这些研究还具有通过以下方式过渡到临床环境的巨大潜力： 使用药理学 PAI-1 抑制剂。