Defining regenerative potential in the cardiac conduction system

定义心脏传导系统的再生潜力

• 批准号: 9397893
• 负责人: NIKHIL Vilas MUNSHI
• 金额: $ 40.5万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9397893
• 关键词: Ablation; Address; Adult; Adverse effects; Affect; Alleles; Anti-Arrhythmia Agents; Arrhythmia; Birth; Cardiac; Cardiac Myocytes; Cardiac conduction system; Cardiovascular system; Cell Cycle; Cell Differentiation process; Cell division; Cells; Cessation of life; Data; Defect; Degenerative Disorder; Electrophysiology (science); Ensure; Failure; Foundations; Functional disorder; Future; GATA4 gene; Genetic; Goals; Heart Atrium; Impairment; Injury; Knockout Mice; LoxP-flanked allele; Modeling; Molecular; Mus; Muscle Cells; Natural regeneration; Neonatal; Neurons; Pathway interactions; Public Health; Recovery; Research; Resolution; Role; Safety; Structure; System; Testing; Transgenic Organisms; Ventricular; Work; base; cardiac repair; cdc Genes; cell type; clinical practice; drug development; heart electrical activity; heart rhythm; improved; in vivo; injury and repair; innovation; insight; interdisciplinary approach; novel; novel strategies; novel therapeutic intervention; novel therapeutics; overexpression; prevent; progenitor; programs; regenerative; repaired; response to injury; tool; transcriptome sequencing

Defining regenerative potential in the cardiac conduction system PROJECT SUMMARY Many cardiac arrhythmias result from damage to the cardiac conduction system (CCS), which orchestrates car- diac electrical activity to ensure regular contractile function. Similar to atrial and ventricular myocytes, CCS cells arise from cardiomyocyte progenitors, but in contrast they undergo terminal differentiation and cell-cycle exit prior to birth. Although regenerative capacity is strongly correlated with active cell division, the regenerative potential of the CCS has not been directly evaluated. The long-term goal of our research program is to devise new therapeutic approaches for acquired arrhythmias. The overall objective of this proposal is to examine the neonatal regenerative capacity of the atrioventricular conduction system (AVCS), a CCS structure that coordi- nates atrioventricular (AV) synchrony. There is an urgent need to elucidate the cellular and molecular underpin- nings of AVCS regeneration to establish a potentially new pathway for treatment of cardiac arrhythmias. Using a novel genetic system for ablating AVCS cardiomyocytes generated in our lab, we found that adult AVCS abla- tion results in persistent atrioventricular (AV) conduction defects, contractile dysfunction, and a failure to regen- erate. In contrast, neonatal AVCS injury led to spontaneous recovery from subtotal injury, providing the first definitive evidence for regenerative potential within the CCS. Building on this observation, our central hypothesis is that the AVCS regenerates by reconstructing its native configuration via proliferation and electrical remodeling of pre-existing cardiomyocytes. To test our hypothesis, we propose the following Specific Aims: 1) Determine the cellular mechanisms that underlie AVCS regeneration, 2) Define the functional role of Gata4/6 during AVCS regeneration, and 3) Establish molecular mechanisms by which Gata4/6 regulate AVCS regeneration. In Aim 1, we will use our AVCS injury system and cell type-specific immunostaining markers to identify the major cell types that contribute to AVCS regeneration. In Aim 2, we will use our AVCS injury system in conjunction with Gata4/6 floxed and conditional overexpression alleles to characterize their role during AVCS regeneration. In Aim 3, we will perform immunostaining, cellular electrophysiology, and RNA-Seq analysis to define the molecular mecha- nisms by which Gata4/6 influence AVCS regeneration. Successful completion of the proposed project will de- lineate critical cellular and molecular features of AVCS regeneration. This contribution will be significant because such insight will establish proof-of-concept that regeneration can impact recovery from dysrhythmia. Further- more, the proposed research is innovative because our unique set of transgenic tools enables detailed in vivo interrogation of AVCS regeneration to establish a potentially new therapeutic paradigm for resolution of cardiac dysrhythmia. Taken together, we anticipate that the results of the proposed project will define critical cellular and molecular features of AVCS regeneration and establish a foundation for future pathway-specific studies and anti- arrhythmic drug development.

定义心脏传导系统中的再生电位 项目摘要 许多心律失常是由心脏传导系统（CCS）受损引起的，心脏传导系统（CCS）负责协调心脏传导， 舒张末期电活动，以确保有规律的收缩功能。与心房和心室肌细胞类似，CCS细胞 起源于心肌祖细胞，但相反，它们经历终末分化和细胞周期退出 在出生之前。虽然再生能力与活跃的细胞分裂密切相关，但再生能力与细胞分裂密切相关。 CCS的潜力尚未得到直接评估。我们研究计划的长期目标是 获得性心律失常的新治疗方法。本建议的总体目标是审查 房室传导系统（AVCS）的新生儿再生能力，这是一种协调 房室（AV）同步。迫切需要阐明细胞和分子基础- AVCS再生的可能性，以建立治疗心律失常的潜在新途径。使用 一种新的基因系统消融AVCS心肌细胞在我们的实验室产生，我们发现，成人AVCS abla- 结果持续性房室（AV）传导缺陷，收缩功能障碍，以及再生失败， erate。相反，新生儿AVCS损伤导致次全损伤的自发恢复，提供了第一个 CCS内再生潜力的明确证据。基于这一观察，我们的核心假设 AVCS通过增殖和电重构重建其天然构型而再生 已经存在的心肌细胞。为了验证我们的假设，我们提出了以下具体目标：1）确定 AVCS再生的细胞机制，2）定义Gata4/6在AVCS过程中的功能作用 3）建立Gata4/6调控AVCS再生的分子机制。在目标1中， 我们将使用我们的AVCS损伤系统和细胞类型特异性免疫染色标记来识别主要的细胞类型 这有助于AVCS再生。在目标2中，我们将使用我们的AVCS伤害系统与Gata 4/6结合使用 floxed和条件性过表达等位基因，以表征其在AVCS再生过程中的作用。在目标3中，我们 将进行免疫染色，细胞电生理学和RNA-Seq分析，以确定分子机制， Gata4/6影响AVCS再生的机制。成功完成拟议项目将使- 划线AVCS再生的关键细胞和分子特征。这一贡献将是巨大的，因为 这样的洞察力将建立概念验证，即再生可以影响从心律失常的恢复。此外─ 更重要的是，所提出的研究是创新的，因为我们独特的一套转基因工具，使详细的体内 探讨AVCS再生以建立一种潜在的新的治疗模式， 心律失常综上所述，我们预计，拟议项目的结果将定义关键的蜂窝和 AVCS再生的分子特征，并为未来的通路特异性研究和抗- 药物研发。