Mechanical Stress-Dependent Remodeling of the Cardiac Microtubule Network

心脏微管网络的机械应力依赖性重塑

基本信息

批准号：
10359060
负责人：
Kenneth Ber Margulies
金额：
$ 68.72万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-01 至 2025-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10359060
关键词：
Address Animal Model Architecture Automobile Driving Biological Models C-terminal Cardiac Cardiac Myocytes Cells Chronic Complement Complex Custom Cytoskeleton Data Defect Dependence Desmin Elastomers Electric Stimulation Enzymes Equilibrium Excision Extracellular Matrix Fibrosis Functional disorder Gene Proteins Genetic Goals Heart Heart Hypertrophy Heart failure Human Hypertension Hypertrophy Image Impairment In Situ In Vitro Intermediate Filaments Left Ventricular Remodeling MAP2K6 gene MAP4 Measurement Measures Mechanical Stress Mechanics Microtubule Stabilization Microtubules Modeling Muscle Cells Myocardium Myofibrils Myofibroblast Network-based Organ Pathologic Patients Pharmacology Process Relaxation Research Research Design Resistance Resolution Risk Role Sarcomeres Stress Stretching Structure Tail Testing Therapeutic Time Tissue Engineering Tissue Model Tissue constructs Tissues Tubulin Tyrosine Update Ventricular Function Work cardiac tissue engineering cardiovascular risk factor clinical translation density experience experimental study genetic approach genetic manipulation heart function hemodynamics hypertensive hypertensive heart disease improved in vivo induced pluripotent stem cell insight mechanical force mechanical properties mouse model new therapeutic target novel pressure prevent stressor targeted treatment therapeutic target tissue stress viscoelasticity

项目摘要

Heart failure is often marked by stiffening of cardiac tissue that impairs the heart’s ability to relax. The microtubule network – a part of the cardiomyocyte cytoskeleton – provides an internal stiffness that can impede cardiomyocyte contraction and relaxation. We have recently found that cardiomyocyte microtubule network stiffness is tightly regulated by post-translational detyrosination and that microtubules, detyrosination, and cytoskeletal cross-linkers are consistently elevated in heart failure, with concomitant increases in cardiomyocyte stiffness. Our findings that reducing detyrosination lessens microtubule network density and contractile defects in cardiomyocytes from patients with advanced heart failure supports detyrosination as a therapeutic target. At the same time, these findings raise important questions about the processes driving remodeling of the microtubule network in heart failure and the consequences of sustained increases in the microtubule network over time. Accordingly, the proposed research will test the hypothesis that remodeling of the cardiac microtubule network is a reversible adaptation to altered mechanical stress, which when sustained, contributes to pathological hypertrophy and contractile dysfunction. Studies under three aims will address the multiple components of this hypothesis. Aim 1 experiments will determine if mechanical stress is sufficient to drive cell-autonomous remodeling of the microtubule network using a mechanobiology toolkit to isolate the contribution of three key mechanical stressors (pre-load, after-load, and matrix stiffness) on microtubule network remodeling. Aim 2 experiments will extend our mechanical manipulations to the tissue and organ level to characterize microtubule network remodeling under relevant in vivo contexts. Aim 3 studies will employ in vitro and in vivo genetic manipulations to determine whether sustained increases in detyrosination contribute to pathologic cardiac hypertrophy in the presence and absence of chronic pressure overload. Our overall study design uses novel and complementary experimental approaches to both exploit strengths of model systems and mitigate their shortcomings. This includes primary cardiomyocytes from human myocardium to complement findings from animal models and engineered tissue constructs. This cross-species, multi-scale approach balances the dual goals of reductionist rigor and integrative relevance that furthers ultimate clinical translation. Together this work will provide insight into the causes of microtubule network changes in heart failure and help determine if preventing or reversing these changes is therapeutically beneficial.

心力衰竭的特点通常是心脏组织僵硬，损害心脏的松弛能力。微管网络是心肌细胞细胞骨架的一部分，其内部僵硬会阻碍心肌细胞的收缩和舒张。我们最近发现心肌细胞微管网络僵硬。受到翻译后去酪氨酸的严格调节，并且微管、去酪氨酸和细胞骨架交联剂在心力衰竭中持续升高，我们的研究结果表明，减少去酪氨酸可以减轻晚期心力衰竭患者心肌细胞的微管网络密度和收缩缺陷，同时，这些发现提出了关于驱动重构过程的重要问题。心力衰竭中的微管网络以及微管网络随时间持续增加的后果因此，拟议的研究将检验心脏微管网络的重塑是一种可逆适应的假设。改变的机械应力，当持续时，会导致病理性肥大和收缩功能障碍。三个目标下的研究将解决该假设的多个组成部分，目标1实验将确定机械应力是否足以驱动微管网络的细胞自主重塑。一个机械生物学工具包，用于分离微管网络重塑中三个关键机械应力源（预加载、后加载和基质刚度）的贡献，目标 2 实验将我们的机械操作扩展到组织和组织。目标 3 研究将采用体外和体内遗传操作来确定在存在或不存在慢性压力超负荷的情况下，去酪氨酸的持续增加是否会导致病理性心脏肥大。设计使用新颖和互补的实验方法来利用模型系统的优点并减轻其缺点，这包括来自人类心肌的原代心肌细胞以及来自动物模型和工程组织结构的补充发现。多尺度方法平衡了还原论严谨性和综合相关性的双重目标，进一步促进了最终的临床转化，这项工作将深入了解心力衰竭微管网络变化的原因，并帮助确定预防或逆转这些变化是否具有治疗益处。