Functional Consequences of FHC-linked RLC Mutations.

FHC 相关 RLC 突变的功能后果。

基本信息

批准号：
7603103
负责人：
Danuta Szczesna-Cordary
金额：
$ 38.77万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-07-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7603103
关键词：
ATP phosphohydrolase Actins Address Affect Affinity Animal Model Arts Atrial Myosins Atrial Natriuretic Factor Attenuated Binding Binding Proteins Binding Sites Biological Assay Buffers Calcium Calmodulin Cardiac Cardiac Death Cardiac Muscle Contraction Cardiovascular Diseases Cells Contractile Proteins Development Disease Dissociation Dyspnea EF Hand Motifs Echocardiography Electrocardiogram Energy Metabolism Event Evolution Familial Hypertrophic Cardiomyopathy Family Fatigue Filament Functional disorder Generations Genes Health Heart Heart Hypertrophy Heart failure Hematoxylin and Eosin Staining Method Histopathology Human Hypertrophy Immunofluorescence Immunologic In Vitro Induced Mutation Intervention Kinetics Knowledge Laboratories Lead Light Link Measures Mechanics Mediating Medical Messenger RNA Metals Microfilaments Molecular Monitor Morphology Mus Muscle Muscle Contraction Muscle Fibers Muscle relaxation phase Mutant Strains Mice Mutate Mutation Myocardium Myofibrils Myosin ATPase Myosin Alkali Light Chains Myosin Heavy Chains Myosin Light Chain Kinase Myosin Regulatory Light Chains Organ Pathology Performance Performance at work Phenotype Phosphorylation Physiological Play Preparation Process Production Property Proteins Pump Regulation Relaxation Research Role Sarcomeres Sarcoplasmic Reticulum Severities Site Skin Solutions Staining method Stains Techniques Testing Therapeutic Tissues Transcript Transgenic Animals Transgenic Mice Transgenic Organisms Troponin C Troponin I Ventricular Work age related base blood pump cell motility heart function hemodynamics improved in vivo innovation insight interdisciplinary approach intermolecular interaction mortality mouse model mutant myosin-binding protein C novel optical traps papillary muscle phospholamban premature prevent protein expression research study single molecule skeletal sudden cardiac death

项目摘要

DESCRIPTION (provided by applicant): Familial hypertrophic cardiomyopathy (FHC) is one of the pathological compensatory manifestations found in the heart resulting from its inability to adequately pump blood, thus leading to hypertrophy and often to premature cardiac death. Over the past 4 years our laboratory has been studying the functional consequences of several FHC mutations in the regulatory light chain (RLC) of myosin expressed in transgenic mice. We hypothesize that by changing the properties of the RLC Ca2+-Mg2+ binding site, the FHC mutations interfere with the intracellular function of RLC as a temporary delayed Ca2+- buffer and lead to increased or decreased kinetics of muscle relaxation. Another hypothesis pertains to the mutation controlled metal occupancy of the Ca2+-Mg2+ binding site of RLC and the mechanism by which Ca2+ or Mg2+ binding to RLC may influence the interaction of myosin with actin and tension generation. We further hypothesize that an FHC induced pathological cardiac phenotype can be rescued by Ca2+-calmodulin activated MLCK phosphorylation of the RLC-mutated myocardium. This application will continue the use of integrated multidisciplinary approaches from single molecule, cell to organ levels and novel transgenic mouse models to address the following questions: SPECIFIC AIM 1: Do FHC induced changes in the properties of the RLC Ca2+-Mg2+ binding site inhibit or facilitate the function of RLC as a temporary intracellular calcium buffer? Do FHC mutations shift the metal occupancy of the RLC Ca2+-Mg2+ binding site during muscle contraction? SPECIFIC AIM 2: Is RLC phosphorylation by Ca2+-calmodulin (CaM) activated myosin light chain kinase (MLCK) affected by FHC-linked RLC mutations? Can MLCK phosphorylation rescue a mutation induced pathological cardiac phenotype? SPECIFIC AIM 3: Do FHC-associated mutations in RLC alter intermolecular interactions between RLC and myosin heavy chain (HC) and ultimately myosin and actin? Do these changes lead to myofilament disarray, cardiac hypertrophy and dysfunction of the mutated myocardium? Successful execution of this proposal will result in new mechanical, physiological and histological information regarding the role of the RLC in cardiac muscle contraction in health and disease. Relevance: Cardiovascular diseases are the number one cause of mortality worldwide with heart failure being highly prevalent in most affluent parts of the world. There is an urgent need for a better understanding of the mechanisms underlying Familial Hypertrophic Cardiomyopathy (FHC) that often leads to premature sudden cardiac death (SCD). This proposal addresses the mechanisms by which the mutations in myosin regulatory light chain (RLC) cause FHC and lead to SCD. Determining the mechanisms of the RLC- mediated regulation of contraction in the healthy and hypertrophic heart will provide insight and be instrumental in developing specific therapeutic strategies that can be employed to reverse or prevent FHC RLC pathology.

描述（申请人提供）：家族性肥厚型心肌病（FHC）是心脏中发现的一种病理代偿性表现，由于心脏无法充分泵血，从而导致肥厚并常常导致心源性过早死亡。在过去的 4 年里，我们的实验室一直在研究转基因小鼠中表达的肌球蛋白调节轻链 (RLC) 的几个 FHC 突变的功能后果。我们假设，通过改变 RLC Ca2+-Mg2+ 结合位点的特性，FHC 突变会干扰 RLC 作为临时延迟 Ca2+- 缓冲剂的细胞内功能，并导致肌肉松弛动力学的增加或减少。另一个假设涉及 RLC Ca2+-Mg2+ 结合位点的突变控制金属占据以及 Ca2+ 或 Mg2+ 与 RLC 结合可能影响肌球蛋白与肌动蛋白相互作用和张力产生的机制。我们进一步假设 FHC 诱导的病理心脏表型可以通过 Ca2+-钙调蛋白激活 RLC 突变心肌的 MLCK 磷酸化来挽救。本申请将继续使用从单分子、细胞到器官水平和新型转基因小鼠模型的综合多学科方法来解决以下问题：具体目标 1：FHC 是否诱导 RLC Ca2+-Mg2+ 结合位点特性的变化抑制或抑制促进 RLC 作为临时细胞内钙缓冲液的功能？ FHC 突变是否会改变肌肉收缩过程中 RLC Ca2+-Mg2+ 结合位点的金属占据？具体目标 2：Ca2+-钙调蛋白 (CaM) 激活的肌球蛋白轻链激酶 (MLCK) 引起的 RLC 磷酸化是否受到 FHC 相关 RLC 突变的影响？ MLCK 磷酸化能否挽救突变诱导的病理心脏表型？具体目标 3：RLC 中 FHC 相关突变是否会改变 RLC 和肌球蛋白重链 (HC) 以及最终肌球蛋白和肌动蛋白之间的分子间相互作用？这些变化是否会导致肌丝紊乱、心肌肥大和突变心肌功能障碍？该提案的成功执行将产生有关 RLC 在健康和疾病中心肌收缩中的作用的新的机械、生理和组织学信息。相关性：心血管疾病是全球第一大死因，心力衰竭在世界上最富裕的地区非常普遍。迫切需要更好地了解家族性肥厚型心肌病 (FHC) 的潜在机制，该病通常导致过早心源性猝死 (SCD)。该提案探讨了肌球蛋白调节轻链 (RLC) 突变导致 FHC 并导致 SCD 的机制。确定健康肥厚心脏中 RLC 介导的收缩调节机制将提供见解，并有助于制定可用于逆转或预防 FHC RLC 病理的特定治疗策略。