Length-dependent activation in human myocardium

人类心肌的长度依赖性激活

基本信息

批准号：
10259881
负责人：
Kenneth S Campbell
金额：
$ 69.46万
依托单位：
UNIVERSITY OF KENTUCKY
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：
2020-09-15 至 2024-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10259881
关键词：
American Biochemical Biological Assay Biophysics Calcium Cardiac Cardiomyopathies Cardiovascular system Computer Models Data Data Set Dependence Development Disease Electrophoresis Genetic Genomics Head Heart Transplantation Heart failure Histologic Histology Human Impairment Infarction Kentucky Length Levosimendan Mus Muscle Cells Muscle Contraction Mutation Myocardial Myocardial Ischemia Myocardium Myosin ATPase Organ Donor Organ Transplantation Patients Penetrance Peptides Pharmacologic Substance Phenotype Physicians Physiologic pulse Pilot Projects Preparation Property Regulation Research Research Personnel Resources Sampling Sarcomeres Scientist Specimen Stretching Structure Sturnus vulgaris Techniques Testing Thick Filament Transplant Recipients Transplantation Universities base biobank biophysical techniques design experimental study gel electrophoresis genomic data human data predictive modeling preservation skills

项目摘要

ABSTRACT This translational project uses human biospecimens procured from organ donors and patients undergoing cardiac transplant to advance understanding of a cellular-level mechanism that underpins the Frank-Starling relationship. Specifically, the project focuses on length-dependent activation, defined as the increased maximum force and Ca2+ sensitivity of contraction induced by myocardial stretch. The mechanisms that underlie length- dependent activation remain unclear, but may involve thick-filament regulation and transitions between the newly discovered OFF and ON states of myosin. Co-PI Campbell has spent a decade building a biobank that now contains >10,000 myocardial specimens from >360 patients. Pilot experiments performed by Co-PI Tanner with these samples show that length-dependent changes in Ca2+ sensitivity are eliminated in myocardium from patients who have non-ischemic heart failure, but preserved in myocardium from organ donors and patients who have ischemic heart failure. New computer modeling predicts that these functional effects reflect destabilization of the myosin OFF state in patients who have non-ischemic heart failure. This hypothesis is supported by additional experiments that used fluorescent polarization techniques to assess OFF/ON dynamics in the thick filaments of human myocardium. Further pilot studies tested the effects of peptides targeted to the thick filament. Peptides that stabilize the OFF state reduced the Ca2+ sensitivity of contraction at long sarcomere length while destabilizing peptides enhanced Ca2+ sensitivity at short length. The length-dependence of these effects was predicted by our computer modeling. The project builds on these data from human biospecimens and integrates the skills and resources of five cardiovascular researchers, a statistician, and a physician-scientist who specializes in advanced heart failure. The Aims explore the global hypothesis that length-dependent activation is reduced in patients who have non- ischemic heart failure because their cardiac thick filaments are biased towards the ON state. Aim 1: Test the hypothesis that length-dependent changes in Ca2+ sensitivity are reduced in myocardium from patients who have non-ischemic heart failure. Aim 2: Test the hypothesis that the OFF state of the thick filament is destabilized in myocardium from patients who have non-ischemic heart failure. Aim 3: Target OFF/ON transitions to manipulate the Ca2+ sensitivity of human myocardium.

抽象的该翻译项目使用从器官捐献者和正在进行的患者采购的人类生物测量心脏移植以提高对基于坦率的细胞水平机制的理解关系。具体而言，该项目着重于长度依赖性激活，定义为增加的最大值心肌拉伸引起的收缩的力和Ca2+敏感性。长度的基础的机制依赖激活仍不清楚，但可能涉及厚丝调节和新近之间的过渡发现并在肌球蛋白的状态下发现。 Co-Pi Campbell花了十年的时间建造了一个生物库，该库现在包含> 10,000个心肌标本 > 360名患者。 Co-Pi Tanner对这些样品进行的试验实验表明长度依赖性心肌的心肌中Ca2+敏感性的变化从患有非缺血性心力衰竭的患者中消除，但由器官捐献者和患有缺血性心力衰竭的患者保存在心肌中。新计算机建模预测，这些功能效应反映了在患者中肌球蛋白关闭状态的不稳定具有非缺血性心力衰竭。该假设得到了使用荧光的其他实验的支持偏振技术评估人类心肌厚细丝中的动力学。进一步的飞行员研究测试了针对厚细丝的肽的作用。稳定下降状态的肽减少在长肌节长度上，收缩的Ca2+敏感性，而破坏肽的稳定增强了Ca2+灵敏度短长。这些效果的长度依赖性通过我们的计算机建模预测。该项目以人类生物测量的这些数据为基础，并整合了五个的技能和资源心血管研究人员，统计学家和专门研究晚期心力衰竭的医师科学家。目的探讨了全球假设，即非长度依赖性激活降低了非 - 缺血性心力衰竭，因为它们的心脏厚细丝偏向于on状态。 AIM 1：检验以下假设：从患有非缺血性心力衰竭的患者。 AIM 2：检验以下假设：厚细丝的关闭状态在患者的心肌中不稳定患有非缺血性心力衰竭的人。 AIM 3：靶向/靶向过渡以操纵人心肌的Ca2+灵敏度。