Endocardial Pathways Regulated by Tbx20

Tbx20 调节的心内膜通路

基本信息

批准号：
8975798
负责人：
SYLVIA M EVANS
金额：
$ 53.62万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
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/8975798
关键词：
Ablation Address Antibodies Bacterial Artificial Chromosomes Binding Binding Sites Bioinformatics Biological Biological Assay Cardiac Cardiomyopathies Cell Lineage Cells Chromatin Data Defect Embryonic Heart Endocardium Endoderm Endothelium Enhancers Epithelial Extracellular Matrix Gene Expression Gene Targeting Genes Genetic Genetic Programming Health Heart Heart Abnormalities Human In Situ In Vitro Left LoxP-flanked allele Maps Mesenchymal Mesenchyme Molecular Morphogenesis Mus Mutation Myocardium Neural Crest Organ Pathway interactions Patients Phenotype Play RNA Reagent Regulation Reporter Genes Role Signal Pathway Somites Staging Testing Tissues Transgenic Mice Validation Ventricular Remodeling Work atrioventricular septal defect cardiogenesis chromatin immunoprecipitation congenital heart disorder genome-wide in vivo insight knock-down mouse development mouse genome mutant planar cell polarity programs research study transcription factor transcriptome transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): Congenital cardiac malformations often include perturbations in outflow tract (OFT) and septal morphogenesis. In humans, mutations in TBX20 are associated with defects in valvulogenesis, septum formation and cardiomyopathy. OFT morphogenesis and cardiac septation require crosstalk between multiple cell lineages, including pharyngeal endoderm, neural crest, second heart field, myocardium, endocardium, and cushion mesenchyme. Global ablation or knockdown of Tbx20 has demonstrated a key role for Tbx20 in multiple aspects of cardiogenesis. Although these studies give insight into biological roles of Tbx20 they leave unanswered the critically important question as to tissue specific requirements for Tbx20 in early heart development. To investigate a potential role for Tbx20 in endocardium, we have utilized Tie2Cre to ablate Tbx20 during early mouse development. Tie2Cre;Tbx20 mutants die around E14 with cardiac defects including DORV, hypoplastic cushions and atrioventricular (AV) septal defects. Endocardial cells of Tie2Cre;Tbx20 mutants demonstrated decreased expression of a number of genes involved in pathways required for OFT morphogenesis, cushion remodeling, and cardiac septation. These pathways include epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) remodeling, and planar cell polarity (PCP). We identified several of these genes as direct targets of Tbx20 by genome-wide chromatin immunoprecipitation (ChIP) in embryonic heart. Two of these targets, Wnt5a and Wnt11, act through a non-canonical Wnt pathway to regulate pathways required for aspects of cardiogenesis which are perturbed in Tie2Cre;Tbx20 mutants, including OFT morphogenesis and cardiac septation. We have identified a Wnt11 enhancer bound by Tbx20 which drives expression of a reporter gene within endocardium of developing mouse heart. From the foregoing, our hypothesis is that Tbx20 in endocardium plays an essential role in OFT and cushion morphogenesis by regulating genes required for EMT, ECM remodeling, and myocardial PCP. To understand mechanisms by which Tbx20 regulates expression of target genes in endocardium, we propose an integrative platform that interrogates the roles of Tbx20 in endocardium with both depth and breadth of scope. We will investigate the phenotypical role of endocardial TBX20 in cushion and OFT morhpogenesis, while uncovering genetic pathways regulated by TBX20 in endocardium. We will identify signaling pathways and transcription factors that serve as co-factors with TBX20 to regulate EMT, ECM remodeling and PCP pathways. We will assess the functional significance of signaling pathways and their intersection with TBX20 in the endocardium. The overall aim of this proposal is to identify key targets of Tbx20 in endocardium which may underlie patient phenotypes, to gain mechanistic insight by understanding how Tbx20 works with other factors to regulate these pathways, and functional consequences of their perturbations for congenital heart disease.

描述（由申请人提供）：先天性心脏畸形通常包括流出道（OFT）和间隔形态发生的扰动。在人类中，TBX20中的突变与瓣膜发生，隔膜形成和心肌病的缺陷有关。经常形态发生和心脏分离需要在多个细胞谱系之间进行串扰，包括咽内胚层，神经rest，第二心脏场，心肌，心内膜心脏和垫子间质。 TBX20的全球消融或敲低表现出了TBX20在心脏病的多个方面的关键作用。尽管这些研究洞悉了TBX20的生物学作用，但他们对早期心脏发育中TBX20的特定于组织的特定要求留下了非常重要的问题。为了研究TBX20在心内膜中的潜在作用，我们在早期小鼠发育过程中利用了TIE2CRE与消融TBX20。 TIE2CRE; TBX20突变体在E14附近死亡，其心脏缺陷，包括DORV，异型垫和房屋（AV）中间缺陷。 TIE2CRE; TBX20突变体的心内膜细胞表现出涉及经常形态发生，缓冲重塑和心脏分离所需途径的许多基因的表达降低。这些途径包括上皮 - 间质转变（EMT），细胞外基质（ECM）重塑和平面细胞极性（PCP）。我们通过胚胎心脏中的全基因组染色质免疫沉淀（CHIP）确定了其中几个基因为TBX20的直接靶标。其中两个靶标，即Wnt5a和Wnt11，通过非规范的WNT途径起作用，以调节心脏病的各个方面所需的途径，这些方面在TIE2CRE中受到扰动； TBX20突变体，包括经常形态发生和心脏分离。我们已经确定了由TBX20结合的Wnt11增强子，该增强子在发育中的小鼠心脏内膜内驱动报告基因的表达。从上述情况下，我们的假设是，内膜中的TBX20通过调节EMT，ECM重塑和心肌PCP所需的基因而在OFT和CUSHION形态发生中起着至关重要的作用。为了理解TBX20调节靶基因在心内膜中的表达的机制，我们提出了一个集成平台，该平台询问TBX20在内膜内的作用，并具有范围的深度和广度。我们将研究心内膜TBX20在缓冲和经常发生的病变中的表型作用，同时揭示了内膜内膜中TBX20调节的遗传途径。我们将确定用作TBX20的共同因素的信号通路和转录因子，以调节EMT，ECM重塑和PCP途径。我们将评估信号通路的功能意义及其与心内膜心脏中TBX20的相交。该提案的总体目的是确定内膜中TBX20的关键靶标，这可能是患者表型的基础，以了解TBX20如何与其他因素一起调节这些途径以及其对先天性心脏病的功能后果，从而获得机械洞察力。