Retinoic acid-dependent mechanisms patterning the cardiac progenitor fields

视黄酸依赖性机制塑造心脏祖细胞区域

• 批准号: 10469323
• 负责人: Tiffany Duong
• 金额: $ 3.96万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10469323
• 关键词: Adult; Affect; Anterior; Cardiac; Cardiac Myocytes; Cardiovascular system; Child; Complication; Congenital Abnormality; Congenital Heart Defects; Country; Data; Development; Double Outlet Right Ventricle; Embryo; Etiology; FGF8 gene; Fibroblast Growth Factor; Generations; Genetic; Genetic Epistasis; Genetic Predisposition to Disease; Goals; Head; Heart; Heart Abnormalities; High Prevalence; Human; Infant; Intake; Knowledge; Lateral; Lead; Light; Medial; Mesoderm; Modeling; Molecular; Molecular Genetics; Mus; Newborn Infant; Operative Surgical Procedures; Pathway interactions; Patients; Pattern; Population; Pregnancy; Regulation; Reporter; Role; Signal Transduction; Testing; Tetralogy of Fallot; Therapeutic; Transgenic Organisms; Tretinoin; Up-Regulation; Vertebrates; Vitamin A; Vitamin A Deficiency; Work; Zebrafish; atrioventricular septal defect; cardiogenesis; cardiovascular disorder risk; cardiovascular risk factor; experimental study; heart dimension/size; high risk; improved; in vivo; infant morbidity/mortality; loss of function; mortality; mutant; new therapeutic target; novel; overexpression; phenotypic data; prevent; progenitor; stem cells; targeted treatment; transcription factor; transcriptome sequencing

Project Summary/Abstract Congenital heart defects (CHDs) are the most common type of birth defects, occurring in 1% of newborns. CHDs can lead to infant illness, mortality and can pose a higher risk for cardiovascular complication in adults, even after corrective surgery. Despite their high prevalence, the molecular etiology underlying CHDs are not well understood. To develop targeted therapies for patients with CHDs, it is crucial to understand the fundamental mechanisms that direct cardiac progenitors into the specific heart fields. Our long-term goal is to understand the conserved mechanisms that regulate normal heart development. Early differentiating cardiac progenitors within the anterior lateral plate mesoderm (ALPM) give rise to the first heart field (FHF), while later differentiating progenitors comprise the second heart field (SHF). It is known that retinoic acid (RA) signaling in vivo restricts the cardiac progenitor fields within the ALPM by indirectly repressing FGF signaling during developmental patterning of the embryonic anterior-posterior axis. Studies in mice have indicated that Six transcription factors (TFs) interact with TBX1 to regulate FGF8 signaling during mammalian cardiovascular development. The mechanism by which RA regulates specification of the FHF and SHF within the ALPM is not understood. The specific aims of this proposal are to elucidate the molecular mechanisms by which RA regulates FHF specification through an early tbx1-six2a-Fgf signaling cascade. Tight RA regulation is critical for vertebrate heart development and Six TFs are evolutionarily conserved among vertebrates, with zebrafish Six2a being homologous to mammalian Six2. Interestingly, our preliminary studies in zebrafish indicate that a deficiency in RA predominantly leads to an increase in FHF progenitors cells within the ALPM. Our Bulk RNA-seq analysis of early stage zebrafish embryos revealed an upregulation of six2a in RA-deficient conditions and suggest an earlier requirement for Six TFs in heart development than previously thought. Overexpression of six2a results in anteriorization and larger zebrafish embryo heads, similar to what is observed in the RA-depleted mutants. However, we currently have no understanding of the signaling network functioning downstream of RA signaling to regulate the specification of FHF progenitors within the ALPM. In Aim 1, we will use novel six2a-reporter transgenic lines and six2a mutants to determine if excess Six2a contributes to the enlarged FHF progenitor population in RA signaling deficient embryos. In Aim 2, we will perform genetic epistasis experiments to determine if Six2a functions within a Tbx1-FGF signaling network downstream of RA signaling to limit CM progenitor specification within the ALPM. Due to the role of RA in vertebrate heart development and the conservation of Six TFs, these studies will greatly improve our understanding on how disruption in the pathways that control the differentiation of cardiac progenitor populations can lead to CHDs in humans. As a result, these studies will allow for the development of better therapeutics to treat CHDs in children as well as adults with cardiovascular complications resulting from CHDs.

项目概要/摘要 先天性心脏病 (CHD) 是最常见的出生缺陷类型，发生于 1% 的新生儿。冠心病 可导致婴儿患病、死亡，并可增加成人心血管并发症的风险，甚至 矫正手术后。尽管冠心病患病率很高，但其分子病因学尚不清楚 明白了。为了开发针对先心病患者的靶向疗法，了解基本原理至关重要 引导心脏祖细胞进入特定心脏区域的机制。我们的长期目标是了解 调节正常心脏发育的保守机制。早期分化的心脏祖细胞 前侧板中胚层 (ALPM) 产生第一心区 (FHF)，随后分化 祖细胞包括第二心脏区域（SHF）。众所周知，视黄酸（RA）信号传导在体内限制 通过在发育过程中间接抑制 FGF 信号传导来调节 ALPM 内的心脏祖细胞区域 胚胎前后轴的模式。小鼠研究表明，六种转录因子 (TF) 与 TBX1 相互作用，在哺乳动物心血管发育过程中调节 FGF8 信号传导。这 RA 在 ALPM 内调节 FHF 和 SHF 规范的机制尚不清楚。这 该提案的具体目的是阐明 RA 调节 FHF 的分子机制 通过早期的 tbx1-62a-Fgf 信号级联规范。严格的 RA 调节对于脊椎动物心脏至关重要 六个 TF 在脊椎动物中进化上是保守的，其中斑马鱼 Six2a 是 与哺乳动物 Six2 同源。有趣的是，我们对斑马鱼的初步研究表明， RA 主要导致 ALPM 内 FHF 祖细胞的增加。我们的 Bulk RNA-seq 分析 早期斑马鱼胚胎揭示了在 RA 缺陷条件下 Six2a 的上调，并表明早期 心脏发育对六个转录因子的要求比以前想象的要高。 Six2a 的过度表达导致 前化和更大的斑马鱼胚胎头部，类似于在 RA 耗尽的突变体中观察到的情况。 然而，我们目前对RA信令下游的信令网络功能尚不了解 调节 ALPM 内 FHF 祖细胞的规格。在目标 1 中，我们将使用新颖的 Six2a-reporter 转基因品系和 Six2a 突变体，以确定过量的 Six2a 是否会导致 FHF 祖细胞增大 RA信号缺陷胚胎中的群体。在目标 2 中，我们将进行遗传上位实验 确定 Six2a 是否在 RA 信令下游的 Tbx1-FGF 信令网络内发挥作用以限制 CM ALPM 中的祖先规范。由于 RA 在脊椎动物心脏发育中的作用以及 六个转录因子的保护，这些研究将极大地提高我们对这些途径如何被破坏的理解 控制心脏祖细胞群分化的基因可能导致人类罹患冠心病。结果，这些 研究将有助于开发更好的疗法来治疗患有先天性心脏病的儿童和成人 CHD 引起的心血管并发症。