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：
7466172
负责人：
Danuta Szczesna-Cordary
金额：
$ 41.41万
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/7466172
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 Cessation of life Condition 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 Invasive 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 Numbers 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 Skeletal system 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 prevent protein expression research study single molecule 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（由申请人提供）：家族性肥厚性心肌病（FHC）是由于无法充分泵血而导致的心脏中的病理补偿性表现之一，因此导致肥大，通常导致心脏死亡过早。在过去的四年中，我们的实验室一直在研究转基因小鼠中表达的肌球蛋白的调节轻链（RLC）中几个FHC突变的功能后果。我们假设通过更改RLC Ca2+-MG2+结合位点的性质，FHC突变会干扰RLC的细胞内功能作为临时延迟的Ca2+ - 缓冲液，并导致肌肉放松动力学的增加或减少。另一个假设与RLC的Ca2+ -mg2+结合位点的突变控制金属占用率以及Ca2+或Mg2+与RLC结合的机制可能影响肌动蛋白与肌动蛋白和张力产生的相互作用。我们进一步假设，FHC诱导的病理心脏表型可以通过Ca2+ - 钙符蛋白激活的MLCK磷酸化来挽救RLC-膜性心肌的MLCK磷酸化。该应用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：特定目标1：是否诱导RLC Ca2+ -mg2+结合位点抑制或促进RLC作为临时的内细胞内细胞内钙化层的功能？ FHC突变是否会在肌肉收缩期间转移RLC Ca2+ -mg2+结合位点的金属占用率？具体目标2：Ca2+-calmodulin（CAM）激活的肌球蛋白轻链激酶（MLCK）是否受FHC连接的RLC突变影响？ MLCK磷酸化可以挽救突变引起的病理心脏表型吗？特定目的3：RLC中与FHC相关的突变会改变RLC与肌球蛋白重链（HC）以及最终肌球蛋白和肌动蛋白之间的分子间相互作用吗？这些变化是否导致突变性心肌的肌膜混乱，心脏肥大和功能障碍？该提案的成功执行将导致有关RLC在心脏肌肉收缩在健康和疾病中的作用的新机械，生理和组织学信息。相关性：心血管疾病是全球死亡率的第一名，心力衰竭在世界上大多数富裕地区都非常普遍。迫切需要更好地了解家族性肥厚性心肌病（FHC）的机制，该机制通常导致心脏突然死亡过早（SCD）。该提案探讨了肌球蛋白调节轻链（RLC）导致FHC并导致SCD的机制。确定健康和肥厚心脏中RLC介导的收缩调节的机制将提供洞察力，并有助于开发可用于逆转或预防FHC RLC病理的特定治疗策略。