Mechanobiology of Vascular Remodeling in Pulmonary Arterial Hypertension

肺动脉高压血管重塑的力学生物学

基本信息

批准号：
8887377
负责人：
LAURA ELIZABETH FREDENBURGH
金额：
$ 41.3万
依托单位：
BRIGHAM AND WOMEN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-14 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8887377
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 Health 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 pulmonary arterial hypertension pulmonary artery endothelial cell response targeted treatment therapeutic target transcription factor

项目摘要

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，其特征是抗凋亡的肺动脉内皮细胞（PAEC）和平滑肌细胞（PASMC）过度增殖，进行性肺动脉（PA）硬化，最终导致肺动脉高压。右心衰竭而死亡。最近的研究表明，PA 僵硬增加会显着增加右心室后负荷，并与 PAH 患者死亡率增加相关，但 PA 僵硬在 PAH 发病机制中的作用尚未完全阐明。我们使用原子力显微镜 (AFM) 微压痕在实验性 PAH 中以前所未有的微观尺度机械表征肺动脉的硬度。我们的初步研究结果表明，在 SU5416/缺氧和野百合碱 (MCT) 诱导的 PAH 大鼠模型中，远端肺动脉基质硬度显着增加三倍以上。此外，在具有重塑肺动脉硬度的聚丙烯酰胺基质上生长的人 PASMC 和 PAEC 会产生惊人的过度增殖表型，环加氧酶 (COX)-2 表达减少，前列腺素 I2 合成减少，内皮素-1 分泌增加。总而言之，我们的研究结果表明，PA 壁中的基质重塑从根本上使细胞行为偏向于通过以前未认识到的基质硬化效应进行渐进性血管重塑。我们假设 PA 硬度的增加不仅仅是血管壁病理改变的结果，而且基质硬度的增加触发了一种“重塑表型”，其特征是肺动脉中细胞增殖和基质沉积增强，促进机械生物反馈血管重塑的放大。为了检验我们的假设，我们提出了三个具体目标。在具体目标 1 中，我们将研究实验性 PAH 期间 PA 刚度的时间和空间增加以及机械变化的可逆性。我们将利用 AFM 微压痕在 SU5416/缺氧和 MCT 诱导的 PAH 大鼠模型中在微米空间尺度上表征远端肺动脉的局部机械环境。在具体目标 2 中，我们将确定基质硬度的增加是否会触发人类 PASMC 和 PAEC 中的“重塑表型”，并研究 COX-2 在协调这些硬度依赖性细胞改变中的作用。我们将研究硬度调节 COX-2 表达的分子机制，并测试 COX-2 衍生的前列腺素的硬度依赖性调节是否驱动血管重塑的反馈放大。在具体目标 3 中，我们将阐明硬度如何调节基因表达，并确定参与人类 PASMC 和 PAEC 硬度依赖性基因调节的关键转录因子。我们将使用转录分析和生物信息学方法，以及新型动态硬化水凝胶系统，对在硬度驱动的过度增殖细胞表型出现过程中的时间基因表达进行公正的分析。