Mechanobiology of Vascular Remodeling in Pulmonary Arterial Hypertension

肺动脉高压血管重塑的力学生物学

• 批准号: 8690140
• 负责人: LAURA ELIZABETH FREDENBURGH
• 金额: $ 40.07万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-14 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8690140
• 关键词: Apoptosis; Atomic Force Microscopy; Attenuated; BMPR2 gene; Behavior; Bioinformatics; Biological feedback; Candidate Disease Gene; Cell Proliferation; Cells; Cessation of life; Cytoskeleton; Deposition; Development; Disease; Distal; Employee Strikes; Endothelin-1; Environment; Epoprostenol; Equilibrium; Failure; Feedback; Gel; Gene Expression; Gene Expression Regulation; Genes; Goals; Heart; Heart failure; Human; Hydrogels; Hypoxia; Inflammation; Lead; Lung; Measurement; Mechanics; Mediator of activation protein; Modeling; Molecular; Monocrotaline; Mutation; Pathogenesis; Pathologic; Pathway interactions; Patients; Phenotype; Prostaglandins; Pulmonary artery structure; RNA Interference; Rattus; Regulation; Research; Resistance; Right Ventricular Dysfunction; Role; SU 5416; Side; Smooth Muscle Myocytes; System; Testing; Time; Traction; Transcriptional Activation; Vascular remodeling; Ventricular; arterial stiffness; cell growth; cyclooxygenase 2; hemodynamics; insight; mortality; novel; novel therapeutic intervention; polyacrylamide; polyacrylamide gels; prevent; public health relevance; pulmonary arterial hypertension; pulmonary artery endothelial cell; response; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): Pulmonary arterial hypertension (PAH) is a severe disease characterized by excessive proliferation of apoptosis-resistant pulmonary artery endothelial cells (PAEC) and smooth muscle cells (PASMC), progressive pulmonary arterial (PA) stiffening, and ultimately right heart failure and death. Recent studies suggest that increased PA stiffness contributes significantly to increased right ventricular after-load and is associated with increased mortality in PAH patients, however the role of PA stiffening in the pathogenesis of PAH has not yet been fully elucidated. We have used atomic force microscopy (AFM) micro-indentation to mechanically characterize the stiffness of pulmonary arteries at an unprecedented micro-scale level in experimental PAH. Our preliminary findings demonstrate that distal pulmonary arteries develop significant increases in matrix stiffness by more than three-fold in the rat models of SU5416/hypoxia and monocrotaline (MCT)-induced PAH. Furthermore, human PASMC and PAEC grown on polyacrylamide substrates with the stiffness of remodeled pulmonary arteries develop a striking hyper-proliferative phenotype, decreased expression of cyclooxygenase (COX)-2, reduced prostaglandin I2 synthesis, and increased secretion of endothelin-1. Taken together, our findings suggest that matrix remodeling in the PA wall fundamentally biases cellular behavior towards progressive vascular remodeling via previously unrecognized effects of matrix stiffening. We hypothesize that increases in PA stiffness are not merely a consequence of pathological alterations in the vessel wall, but rather that increases in matrix stiffness trigger a "remodeling phenotype" characterized by enhanced cellular proliferation and matrix deposition in pulmonary arteries, promoting mechano-biological feedback amplification of vascular remodeling. To test our hypothesis, we propose three specific aims. In Specific Aim 1, we will investigate the temporal and spatial increases in PA stiffness and reversibility of mechanical changes during experimental PAH. We will utilize AFM micro-indentation to characterize the local mechanical environment of distal pulmonary arteries at the micron spatial scale in the rat models of SU5416/hypoxia and MCT-induced PAH. In Specific Aim 2, we will determine whether increases in matrix stiffness trigger a "remodeling phenotype" in human PASMC and PAEC and investigate the role of COX-2 in orchestrating these stiffness- dependent cellular alterations. We will investigate the molecular mechanisms by which stiffness modulates COX-2 expression and test whether stiffness-dependent regulation of COX-2-derived prostanoids drives feedback amplification of vascular remodeling. In Specific Aim 3, we will elucidate how stiffness modulates gene expression and identify key transcription factors involved in stiffness-dependent gene regulation in human PASMC and PAEC. We will use transcriptional profiling and bioinformatic approaches, along with a novel dynamic stiffening hydrogel system, to perform an unbiased analysis of temporal gene expression during the stiffness-driven emergence of the hyper-proliferative cellular phenotype.

描述（由申请人提供）：肺动脉高压（PAH）是一种严重的疾病，其特征是抗凋亡抗凋亡的肺动脉内皮细胞（PAEC）和平滑肌细胞（PASMC），进行性肺动脉粥样硬化（PA）僵硬（PA）僵硬，以及最终的正当心脏失败和死亡。最近的研究表明，PA刚度的增加对右心室后负荷的增加显着贡献，并且与PAH患者的死亡率增加有关，但是PA僵硬在PAH发病机理中的作用尚未完全阐明。我们已经使用了原子力显微镜（AFM）微观指示来机械表征肺动脉在实验性PAH中前所未有的微尺度水平上的刚度。我们的初步发现表明，在SU5416/缺氧和单蛋白（MCT）诱导的PAH的大鼠模型中，远端肺动脉的基质刚度显着增加了三倍以上。此外，人类PASMC和PAEC在聚丙烯酰胺底物上生长，具有重塑肺动脉的刚度会发展出惊人的超增殖表型，环氧酶（COX）-2的表达降低，降低了前列腺素I2合成的降低，并降低。综上所述，我们的发现表明，PA壁中的基质重塑从根本上偏向于通过先前无法识别的矩阵僵硬作用来逐渐进行性血管重塑。我们假设PA刚度的增加不仅是血管壁中病理改变的结果，而且还导致基质刚度的增加触发了一种“重塑表型”，其特征是细胞增殖和肺动脉中基质沉积的增强，从而促进了机械生物生物学反馈的血管重塑。为了检验我们的假设，我们提出了三个具体目标。在特定的目标1中，我们将研究实验性PAH期间机械变化的PA刚度和可逆性的时间和空间增加。我们将利用AFM微型指示来表征Micron空间尺度远端肺动脉的局部机械环境，在SU5416/缺氧和MCT诱导的PAH的大鼠模型中。在特定的目标2中，我们将确定在人PASMC和PAEC中的矩阵刚度增加是否触发了“重塑表型”，并研究COX-2在修复这些刚度依赖性依赖性细胞变化中的作用。我们将研究刚度调节Cox-2表达并测试COX-2衍生前列腺素的刚度依赖性调节的分子机制，可驱动血管重塑的反馈扩增。在特定的目标3中，我们将阐明刚度如何调节基因表达并确定与刚度依赖性基因调节的关键转录因子在人PASMC和PAEC中。我们将使用转录分析和生物信息学方法，以及一种新型的动态僵硬水凝胶系统，对超增强性细胞表型的刚度驱动的出现期间对时间基因表达进行无偏分析。