Transcriptional regulation of cardiac conduction system morphogenesis

心脏传导系统形态发生的转录调节

• 批准号: 10425653
• 负责人: Anthony B. Firulli
• 金额: $ 1.66万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10425653
• 关键词: Adult; Alleles; Arrhythmia; Awareness; BHLH Protein; Binding Sites; Biological Assay; Biotin; Blood Circulation; Bundle of His; Cardiac; Cardiac Myocytes; Cardiac conduction system; Cardiac development; Cell Lineage; ChIP-seq; Child; Chromatin; Clinical; Complex; Congenital Abnormality; Congenital Heart Defects; Connexins; Contracts; DNA; Data; Development; Disease; Electrocardiogram; Embryo; Enhancers; Event; Functional disorder; GATA4 gene; Gene Expression Regulation; Genes; Genetic Transcription; Genetically Engineered Mouse; Heart; Heart Arrest; Homeostasis; Human; Ion Channel; Lead; Left; Left ventricular structure; Life; Linkage Disequilibrium; Maintenance; Molecular; Morphogenesis; Mus; Mutant Strains Mice; Myocardial; Myocardium; Optics; Pathway interactions; Patients; Periodicity; Physiological; Play; Regulator Genes; Regulatory Pathway; Reporter; Reporting; Role; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Sinoatrial Node; Sodium Channel; Structural Protein; Structure; Structure of purkinje fibers; Systems Development; Testing; Transcriptional Regulation; Transgenic Mice; Transgenic Organisms; Transposase; Untranslated RNA; Variant; Ventricular; atrioventricular node; cell type; chromatin immunoprecipitation; conditional knockout; deep sequencing; gain of function; genetic association; genome wide association study; heart function; heart rhythm; loss of function; mortality risk; muscular structure; mutant; postnatal; transcription factor; transcriptome; voltage

PROJECT SUMMARY/ABSTRACT The propagation of electrical impulses that coordinate the rhythmic and synchronized cardiac contractions to facilitate systemic circulation is regulated by a specialized structures and cell types, the cardiac conduction system (CCS), and working cardiomyocytes in a spatial-temporally precise manner. Congenital defects of the CCS and dysregulation of CCS homeostasis can lead to CCS dysfunction, causing life threatening arrhythmias and increasing the risk of death in both children and adults. Genome Wide Association studies (GWAS) in human patients with various arrhythmias have revealed a close association between abnormal ECG and many ion channels, gap junction proteins, muscle structural proteins as well as a number of critical transcription factors that function in cardiac development and the specification, differentiation and homeostatic maintenance of the CCS, among them include the basic Helix-loop-Helix (bHLH) transcription factor Hand1 and the T-box transcription factor Tbx20. Hand1 is expressed in the early developing hearts and is essential for cardiac morphogenesis. Tbx20 is shown to be critically involved in multiple cardiogenic events and cardiac function. Interestingly, despite Hand1 and Tbx20 are not previously associated with roles in CCS development or function, GWAS analysis revealed single nucleotide polymorphisms (SNPs) within both HAND1 and TBX20 associated with prolonged QRS duration with strong linkage disequilibrium. For both HAND1 and TBX20 these SNPs are intergenic suggesting roles in transcriptional regulation of these genes. Indeed, we have identified a left ventricle (LV) Hand1 enhancer with GATA4 and T-box binding sites that resides within a conserved non-coding sequence (CNS) that lies in between the reported SNPs. Mutant mice that have harbored a gene-edited deletion of this enhancer result in a prolonged QRS. Supporting this finding, we have recently observed that Hand1 is specifically expressed within CCS structures in postnatal hearts. Transcriptional regulation of Tbx20 is expressed in multiple cardiac cell lineages. Myocardial gain- or loss-of- function studies have shown altered QRS duration and severe arrhythmia. Collectively, our overriding hypothesis is that Hand1 and Tbx20 coordinate and maintain the spatial and temporal control of the cardiac conductive system development and function via either parallel or single gene regulatory pathways. We will test this hypothesis with the following specific Aims: 1) to test the hypothesis that adult expression of Hand1 within the CCS is required for maintaining a normal QRS duration; 2) to test the hypothesis that Tbx20 functions in the development and homeostasis of the CCS as well as the maintenance of the conductive function of cardiomyocytes; 3) to test whether Hand1 and Tbx20 serves as key transcriptional regulators for CCS development and CCS physiological function in a common or different regulatory pathways.

项目摘要/摘要 电脉冲的传播，以节奏和同步心脏收缩与 促进全身循环受到心脏传导的专业结构和细胞类型的调节 系统（CCS）和工作心肌细胞的空间精确方式。先天性缺陷 CCS和CCS稳态失调可能导致CCS功能障碍，从而造成威胁生命 心律不齐并增加儿童和成人死亡的风险。基因组广泛的研究 （GWAS）在各种心律不齐的人类患者中表明异常之间有着密切的关联 ECG和许多离子通道，间隙连接蛋白，肌肉结构蛋白以及许多关键 在心脏发展中起作用的转录因子以及规范，分化和稳态 CC的维护，其中包括基本的螺旋 - 环螺旋（BHLH）转录因子手1 和T-box转录因子TBX20。 Hand1在早期发育中的心脏中表达，是必不可少的 用于心脏形态发生。 TBX20被证明与多次心源性事件和心脏 功能。有趣的是，尽管Hand1和tbx20以前与CCS开发中的角色无关 或功能，GWAS分析揭示了Hand1和Tbx20中的单核苷酸多态性（SNP） 与长时间的QRS持续时间相关，具有强烈的连锁不平衡。对于HAND1和TBX20 这些SNP是基因间，暗示在这些基因的转录调节中作用。确实，我们有 鉴定出具有GATA4和T-box绑定位点的左心室（LV）Hand1增强子 保守的非编码序列（CNS）位于报告的SNP之间。具有的突变小鼠 对此增强子进行基因编辑的缺失，导致QRS延长。支持这一发现，我们有 最近观察到的是，手1在产后心脏中的CCS结构中特别表达。 TBX20的转录调节在多个心脏细胞谱系中表达。心肌增益或丧失 功能研究表明，QRS持续时间改变和严重心律不齐。总体而言，我们的压倒力 假设是HAND1和TBX20协调并维持心脏的空间和时间控制 导电系统的开发和功能通过平行或单个基因调节途径。我们将 以以下特定目的检验该假设：1）检验以下假设： 在CC内保持正常QRS持续时间是必需的； 2）检验TBX20的假设 CCS的发展和稳态以及导电的维护 心肌细胞的功能； 3）测试Hand1和TBX20是否是关键的转录调节器 CCS开发和CCS生理功能在常见或不同的调节途径中。