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：
8391535
负责人：
Michael R Zile
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/8391535
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 receptor receptor internalization receptor recycling research study response small molecule success trans-Golgi Network

项目摘要

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 ¿-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 ¿-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 ¿-blocked and have an equivalent degree and duration of physiological vs. pathological hypertrophy, with ex- tensively characterized cytoskeletal properties in each setting.

过去 24 年中由这笔赠款支持的研究是围绕大量数据建立的表明心脏的结构、组成和功能都对心脏的变化做出快速且可逆的反应该资助支持的第一组研究使用了分离的细胞或心肌细胞和完整的细胞。动物证明负荷作为心肌细胞生长的中央调节剂的作用。在这笔拨款的支持下，它也使用负荷变化作为主要实验变量，导致我们发现严重压力超负荷心脏肥大期间致密心肌细胞微管网络的形成导致在这种情况下发生的收缩功能障碍。随后对这种异常微管网络进行研究的最初目标是确定它是如何形成的。主要发现是 1）基于增加的微管蛋白和微管，以及更大的微管稳定性，2）主要的汽车 diac 微管稳定微管相关蛋白 MAP4 在压力超负荷时大幅上调肥大并主要与微管结合，3) 收缩功能障碍是由粘性负荷引起的通过致密的微管网络来缩短肌丝。然而，微管在间期细胞（如心肌细胞）中最重要的正常作用是不是为了确定细胞流变特性，而是为了促进大分子的细胞内运输和囊泡通过运动蛋白的微管相关驱动蛋白和动力蛋白家族。在成年心肌细胞的极度扩散限制的细胞质中具有绝对重要的作用。并且由于已知过度装饰会抑制微管依赖性细胞内运输具有 MAP 的微管，我们接下来询问是否基于微管的激活 ¿ -肾上腺素能受体和/或 mRNA - 核糖核蛋白复合物在压力下被 MAP4 与微管的结合所抑制事实上，情况就是如此。基于这项最新工作，我们建议在此研究微管改变的潜在作用网络组织和 MAP4 结合导致 connexin43 [Cx43] 的异常运输和定位，一种间隙连接蛋白，已知在数量和定位过程中会发生功能上重要的改变第一个目标的基础研究将使用分离的细胞和手术。小鼠和转基因小鼠以确定 MAP4 是否修饰微管以及随之而来的致密化微管网络的重合，抑制 Cx43 到间隙连接的正常转运以及 Cx43 依赖性第二个和第三个目标的转化研究将进行比较。病理性压力与生理性容量超负荷肥大的程度和持续时间相同。首先扩展第一个目标的发现，询问密集微管网络的 MAP4 修饰是否存在于病理性肥大在 Cx43 运输和定位改变中发挥作用，这在临床上很重要然后我们会问是否形成致心律失常底物。 -病理性肥大中的受体阻断，早期数据表明会预防微管表型异常，也会预防Cx43异常在此设置中的表型。在第一个目标中，我们将使用小鼠模型，在第二个和第三个目标中，我们将使用我们的长期生理性肥大与病理性肥大的站立猫模型虽然我们认识到它是更可取的。由于能够使用单一物种，在这项研究中，最初的机械部分只能在小鼠中完成，但是后期的定量转化部分需要非常可重复的动物模型，可以可靠且可验证 ¿ -阻塞并具有同等程度和持续时间的生理性与病理性肥大，前- 在每种情况下都集中表征了细胞骨架特性。