Cellular and Molecular Mechanisms of Left Ventricular Growth and Morphogenesis

左心室生长和形态发生的细胞和分子机制

• 批准号: 8657292
• 负责人: Anthony B. Firulli
• 金额: $ 39万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-15 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8657292
• 关键词: Ablation; Alleles; Animal Model; Automobile Driving; BHLH Protein; Cardiac; Cardiac Myocytes; Cardiac Output; Cell Lineage; Cells; Childhood; Clinical; Common Ventricle; Congenital Abnormality; Congenital Heart Defects; Congenital atresia of pulmonary valve; Development; Embryo; Embryonic Development; Embryonic Heart; Enhancers; Etiology; Gene Expression; Gene Targeting; Genes; Genetic; Germ-Line Mutation; Growth; Growth and Development function; Heart; Helix-Turn-Helix Motifs; Human; Hypoplastic Left Heart Syndrome; Investigation; Knock-out; Left; Left ventricular structure; Light; Lung; Modeling; Molecular; Morphogenesis; Mutation; Myocardial; Myocardium; Neural Crest Cell; Online Mendelian Inheritance In Man; Outcome; Pathway interactions; Patients; Phenotype; Play; Population; Positioning Attribute; Pulmonary artery structure; Regulatory Element; Reporting; Right ventricular structure; Role; Series; Side; Somatic Mutation; Testing; Transcription factor genes; Transgenic Organisms; Tricuspid Atresia; Venous; Ventricular; Ventricular septum; cardiogenesis; congenital heart disorder; gain of function mutation; human disease; insight; loss of function; loss of function mutation; migration; mutant; novel; outcome forecast; programs; public health relevance; transcription factor

PROJECT SUMMARY/ABSTRACT Congenital heart disease (CHD) is the most common birth defect. Among various CHDs, single ventricle phenotypes resulting from altered ventricular morphogenesis have the poorest clinical prognoses and include Tricuspid Atresia (OMIM# 605067), Pulmonary Atresia (OMIM# 265150), and Hypoplastic Left Heart Syndrome (HLHS; OMIM# 241550, 614435). The single ventricle heart presents with a series circuit such that systemic venous return to the right ventricle and pulmonary arteries combined with the flow from the pulmonary venous return into the left ventricle and out to the body is incompatible with survival. Currently, there is a poor understanding of the molecular mechanisms and cellular etiology causative of the many forms of single ventricle CHD. Human mutations in the cardiac transcription factor genes NKX2.5 and HAND1 have been observed in HLHS patients. Modeling and thus the study of possible HLHS phenotypes have been limited as current systemic and conditional knockouts of Nkx2.5 and Hand1 results in embryonic lethality given the broad expression domains of available Cre lines. The lack of a restricted left ventricle Cre driver prohibits such investigations. Hand1 is expressed within the primary heart field myocardium of the left ventricle. We have isolated the enhancer that regulates Hand1 left ventricular expression and used it to generate a novel left ventricular-specific Cre driver with which interrogation of the cellular and molecular mechanism driving left ventricular morphogenesis can be realized. Our experimental plan is to ablate the Hand1 left ventricular lineage cells from the developing embryonic heart, conditionally delete Nkx2.5 specifically within the left ventricular myocardium, and validate an identified human mutation in HAND1 isolated from 24 unrelated patients as being causative of HLHS. This study of the role that Hand1-lineage myocardium plays during cardiogenesis will shed light on the cell etiology of single ventricle phenotypes and on the molecular programs controlling ventricular maturation, thus expanding the understanding of ventricular morphogenesis as it relates to human disease. Relevance: CHDs resulting in single ventricle phenotypes have the poorest clinical outcomes. Thus, gaining an understanding of the etiology and molecular mechanisms that cause CHDs resulting in a single ventricle heart has the potential to benefit thousands of pediatric patients annually. The Hand1-lineage plays a key role in the genesis of single ventricle phenotypes and gaining insight into the cellular and molecular mechanism of this understudied myocardial population will have a great benefit to developing non-surgical treatments for CHD patients.

项目总结/摘要 先天性心脏病（CHD）是最常见的出生缺陷。在各种CHD中，单心室 心室形态发生改变导致的表型具有最差的临床表现，包括 三尖瓣闭锁（OMIM# 605067）、肺动脉闭锁（OMIM# 265150）和左心发育不良综合征 (HLHS; OMIM# 241550，614435）。单心室心脏呈现串联回路，使得全身性 静脉回流到右心室和肺动脉，并与来自肺静脉的血流结合 回到左心室再回到身体是不可能存活的。目前，贫困 了解导致多种形式的单克隆抗体的分子机制和细胞病因学 心室CHD 在HLHS中观察到心脏转录因子基因NKX2.5和HAND 1的人类突变 患者建模和因此可能的HLHS表型的研究已被限制，因为当前的系统和 条件性敲除Nkx2.5和Hand 1导致胚胎致死， 可用的Cre线。由于缺乏受限制的左心室Cre驱动器，因此无法进行此类研究。手1 在左心室的主要心脏区域心肌内表达。我们分离出了一种增强剂 调节Hand 1左心室表达，并使用它来产生一种新的左心室特异性Cre驱动程序 通过这种方法，可以询问驱动左心室形态发生的细胞和分子机制， 实现了我们的实验计划是将Hand 1左心室谱系细胞从发育中的 胚胎心脏，特异性地在左心室心肌内有条件地删除Nkx2.5，并验证了 鉴定了从24名无关患者中分离的HAND 1中的人类突变是HLHS的病因。这 研究Hand 1系心肌在心脏发生过程中的作用将有助于阐明细胞病因学 单心室表型和控制心室成熟的分子程序， 扩大了对心室形态发生的理解，因为它与人类疾病有关。 相关性： 导致单心室表型的CHD具有最差的临床结局。因此， 了解导致单心室心脏的CHD的病因学和分子机制 每年有可能使成千上万的儿科患者受益。Hand 1-lineage在人类基因组中起着关键作用。 单心室表型的发生，并深入了解这种现象的细胞和分子机制， 研究不足的心肌人群将对开发冠心病的非手术治疗方法有很大好处 患者