Connexin Distribution in Physiological Versus Pathological Cardiac Hypertrophy

生理性与病理性心脏肥大中的连接蛋白分布

基本信息

批准号：
7788252
负责人：
GEORGE COOPER
金额：
--
依托单位：
RALPH H JOHNSON VA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-10-01 至 2013-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7788252
关键词：
Accounting Address Adenoviruses Adrenergic Agents Adrenergic Agonists Adrenergic Receptor Adult Affinity Agonist Aliquot Animal Model Animals Applications Grants Arrestins Arrhythmia Atrial Heart Septal Defects Attenuated Basic Science Binding Biopsy Cadherins Canis familiaris Cardiac Cardiac Myocytes Caring Catheterization Cell Adhesion Cell Nucleolus Cell Nucleus Cell surface Cells Characteristics Chronic Clinical Complex Confocal Microscopy Congenital Heart Defects Connexin 43 Connexins Connexon Control Animal Cyclic AMP Cytoplasm Cytoskeleton Data Dependence Diffuse Diffusion Distal Docking Down-Regulation Dynein ATPase Echocardiography Electrocardiogram Electrons Elements Environment Event Exhibits Failure Family Family Felidae Felis catus Functional disorder Funding Gap Junctions Genes Genetic Transcription Genetic screening method Goals Golgi Apparatus Grant Grant Review Growth Heart Heart Diseases Heart Hypertrophy Heart failure Homeostasis Human Hypertrophy Immunoblotting Infection Interphase Cell Intervention Intracellular Transport Kinesin Lead Left Left ventricular structure Life Life Cycle Stages Location Lung Lysosomes MAP4 Maps Measurement Measures Mechanics Mediating Medical center Membrane Membrane Transport Proteins Messenger RNA Metalcaptase Methods Microfilaments Microtubule Depolymerization Microtubule Proteins Microtubule-Associated Proteins Microtubules Minor Modeling Molecular Morphology Motion Motor Mus Myocardial Myocardium Myofibrils Nocodazole Normal Cell Normal Range Optics Pathway interactions Patients Pharmaceutical Preparations Phase Phenotype Phosphoric Monoester Hydrolases Phosphotransferases Physiological Plus End of the Microtubule Positioning Attribute Prevention Principal Investigator Process Program Reviews Progress Reports Property Propranolol Protein Biosynthesis Protein Dephosphorylation Protein Isoforms Protein phosphatase Proteins Protocols documentation Pulmonary artery structure Recruitment Activity Research Research Support Ribonucleoproteins Ribosomal RNA Ribosomes Right ventricular structure Right-On Role Sarcolemma Science Series Site Specificity Staining method Stains Stimulus Stress Structure System Systolic Pressure Telemetry Testing Therapeutic Intervention Thinking Time Tissues Transfection Transgenic Mice Translating Translational Research Translations Transport Process Transport Vesicles Treatment Efficacy Tubulin Up-Regulation Ventricular Vesicle Work adrenergic base beta-adrenergic receptor constriction density extracellular gap junction channel gene therapy hemodynamics improved interest macromolecule member messenger ribonucleoprotein overexpression p21-activated kinase 1 palliative particle pressure prevent programs public health relevance receptor receptor internalization receptor recycling research study response small molecule success trans-Golgi Network

项目摘要

DESCRIPTION (provided by applicant): Research supported by this grant during the previous twenty-four years has been built around extensive data showing that cardiac structure, composition, and function each respond rapidly and reversibly to changes in hemodynamic load. The first set of studies supported by this grant used isolated cells, or cardiocytes, and intact animals to demonstrate the role of load as a central regulator of cardiocyte growth. The second set of studies supported by this grant, which also used load change as the primary experimental variable, led to our discovery of a dense cardiocyte microtubule network during severe pressure-overload cardiac hypertrophy that contrib- utes to the contractile dysfunction which occurs in this setting. The initial goals for the subsequent studies of this abnormal microtubule network were to determine how it contributes to the contractile dysfunction of hypertrophied myocardium. Major findings have been that 1) it is based both on increased tubulin, and thus microtubules, and on greater microtubule stability, 2) the major car- diac microtubule-stabilizing microtubule-associated protein, MAP4, is greatly upregulated in pressure overload hypertrophy and binds extensively to microtubules, and 3) contractile dysfunction is caused by viscous loading imposed on shortening myofilaments by the dense microtubule network. However, the most important normal role of the microtubules in an interphase cell such as the cardiocyte is not to determine cellular rheological properties but rather to subserve intracellular transport of macromolecules and vesicles via the microtubule-associated kinesin and dynein families of motor proteins. Indeed, this is an absolutely essential role in the extremely diffusion-restricted cytoplasm of the adult cardiocyte. For this reason, and because of the known inhibition of microtubule-dependent intracellular transport by excessive decoration of microtubules with MAPs, we next asked if microtubule-based transport of the activated 2-adrenergic receptor and/or mRNA - ribonucleoprotein complexes was inhibited by MAP4 binding to microtubules in pressure- overload hypertrophy. Such, in fact. was the case. Building on this most recent work, we propose to examine here the potential role of alterations in microtubule network organization and MAP4 binding in causing abnormal transport and localization of connexin43 [Cx43], a gap junction protein known to undergo functionally important alterations in quantity and localization during pathological cardiac hypertrophy. The basic research in the first objective will use isolated cells as well as oper- ated and transgenic mice to determine whether MAP4 decoration of microtubules, and the attendant densifica- tion of the microtubule network, inhibit the normal transport of Cx43 to gap junctions as well as Cx43-depen- dent electrophysiological function. The translational research in the second and third objectives will compare an equal degree & duration of pathological pressure vs. physiological volume overload hypertrophy. We will first extend the findings of the first objective to ask if MAP4 decoration of the dense microtubule network in pathological hypertrophy has a role in the altered Cx43 transport and localization that are important clinically in forming an arrhythmogenic substrate. We will then ask if 2-receptor blockade in pathological hypertrophy, which early data indicates will prevent the abnormal microtubule phenotype, will also prevent the abnormal Cx43 phenotype in this setting. In the first objective we will use murine models, and in the second and third objectives we will use our long- standing feline models of physiological versus pathological hypertrophy. While we recognize that it is prefer- able to use a single species, in this research the initial mechanistic portion can only be done in the mouse, but the later quantitative translational portions require very reproducible animal models that can be reliably and verifiably 2-blocked and have an equivalent degree and duration of physiological vs. pathological hypertrophy, with ex- tensively characterized cytoskeletal properties in each setting. PUBLIC HEALTH RELEVANCE: Pathological cardiac hypertrophy is one of the two most common serious cardiac abnormalities which we encounter in the care of our patients in VA Medical Centers. Our attempts to deal in a definitive as opposed to a palliative way with this problem must be based on a mechanistic understanding of the causes of this entity. Preliminary data for this grant application suggest that specific cytoskeletal changes accompanying severe pres- sure overload cardiac hypertrophy may not only be responsible for contractile dysfunction but may also be responsible, at least in part, for altered transport within the cardiac muscle cell that can lead to the rhythm disturbances that characterize heart failure. Since specific endogenous phosphatases and kinases regulate the molecular events that cause these cytoskeletal changes, this work has the potential to lead to very important therapeutic interventions.

描述（由申请人提供）：在过去的二十四年中，这笔赠款支持的研究是围绕大量数据构建的，表明心脏结构，组成和功能每个人都会迅速，可逆地响应血液动力学负荷的变化。该赠款支持的第一组研究使用了孤立的细胞或心脏细胞，以及完整的动物来证明负载是心脏细胞生长的中心调节剂的作用。该赠款支持的第二组研究也将负载变化用作主要的实验变量，这导致我们在严重的压力超负荷心肥大中发现了密集的心脏细胞微管网络，这会导致这种情况下发生的收缩功能障碍。随后研究该异常微管网络的最初目标是确定其如何促进肥大心肌的收缩功能障碍。主要发现是1）它既基于微管蛋白，因此基于微管，以及更高的微管稳定性，2）主要的car- diac微管微管固化的微管微管相关蛋白MAP4，在压力超负荷中大大上调，并与近距离载荷相结合，并与近距离载量相结合。密集微管网络的肌膜。然而，微管在相互相细胞中的最重要正常作用（例如心脏细胞）不是确定细胞流变特性，而是通过微管和囊泡通过微管相关的运动蛋白和染料蛋白族来提供大分子和囊泡的细胞内转运。确实，这在成年心细胞的极限限制细胞质中绝对重要。因此，由于通过地图过度装饰微管对微管依赖性细胞内转运的已知抑制，我们接下来询问是否基于微管的2-肾上腺素能受体和/或mRNA--mRNA-核糖核蛋白复合蛋白复合物的转运是否通过与Map-Map4结合压力 - 超载超载体量抑制了核糖核酸蛋白复合物。实际上，这样。是这样。在这项最新工作的基础上，我们建议在这里检查微管网络组织中改变的潜在作用和MAP4结合在引起异常运输和connexin43的定位[CX43] [CX43]，这是一种缺口连接蛋白，该间隙连接蛋白已知在病理心脏肥大过程中经历功能上重要的数量和定位变化。第一个目标中的基础研究将使用孤立的细胞以及操作和转基因小鼠来确定MAP4微管装饰以及微管网络的随附密度是否抑制CX43对差距差距的正常运输，以及CX43-底齿 - 底齿 - 底齿 - 底齿 - 底膜 - 底膜 - 底膜。第二和第三个目标中的转化研究将比较病理压力与生理体积超负荷肥大的相等程度和持续时间。我们将首先扩展第一个目标的发现，询问病理肥大中密集的微管网络的MAP4在CX43转运和定位中是否在形成心律失常的底物中很重要。然后，我们将询问在病理肥大中的2受体阻断（早期数据表明将防止异常微管表型）是否还会防止在这种情况下的CX43表型异常。在第一个目标中，我们将使用鼠模型，在第二和第三个目标中，我们将使用长期存在的猫科学模型的生理肥大与病理肥大。虽然我们认识到可以使用单一物种，但在这项研究中，初始机械部分只能在鼠标中完成，但是后来的定量翻译部分需要非常可重现的动物模型，这些模型可以可靠，可靠地盖住2块，并且具有等效的程度和持续时间，并具有生理性与病理超级过度的持久性，并具有外观性特性的特性。公共卫生相关性：病理心脏肥大是我们在VA医疗中心照顾患者时遇到的两种最常见的严重心脏异常之一。我们试图以此问题为基础，与姑息性方式进行确定性的尝试必须基于对该实体原因的机械理解。该赠款应用的初步数据表明，伴随严重的支撑性心脏肥大伴随的特定细胞骨架变化不仅可能导致收缩功能障碍，而且至少可能部分负责心肌细胞内的运输改变，从而导致节奏障碍，从而导致心脏失败的节奏障碍。由于特定的内源性磷酸酶和激酶会调节引起这些细胞骨架变化的分子事件，因此这项工作有可能导致非常重要的治疗干预措施。