Cxc12 chemokine signaling regulates synchronous development of coronary vessels and myocardium

项目摘要 冠状动脉血管系统在维持持续的氧气供应方面起着重要作用 和营养物质。冠心病是心肌梗死的主要原因， 心力衰竭，这仍然是世界范围内死亡率的主要原因。尽管 重要的是，调节心肌冠状动脉血管形成的机制仍然是一个重要的问题。 我们的知识差距很大。我们观察到，在斑马鱼心脏发育过程中， 血管与特定的皮质心肌细胞亚群形成密切联系 由转录因子Gata4标记。gata4+心肌细胞跟随冠状动脉的轨迹 当内皮细胞出现在幼年斑马鱼心脏的表面时。 此外，我们的初步数据表明，Cxcl12b趋化因子的表达，一个关键的 血管生成因子在斑马鱼冠状血管发育过程中， GATA 4+心肌细胞。此外，gata4+心肌细胞不能与冠状动脉粥样硬化相关。 缺乏Cxc112b受体Cxcr4a的心脏血管。重要的是，成年cxcr4a突变体 斑马鱼心脏损伤后无法再生。我们假设心脏的发育发生在 由时间上不同的机制调节的两个阶段：新形成的冠状动脉 在新生期，内皮细胞提供了指导性的线索，如旁分泌因子 当GATA 4+心肌细胞出现时，cxcl 12 b引导它们，而在扩张期， GATA 4+心肌细胞表达增加，以吸引冠状血管， 它们的形态发生/发育和再生。我们建议：（1）确定新的 冠状血管引导GATA 4+心肌细胞通过分析 从编码分泌分子的RNAseq中鉴定出差异表达的候选基因 (e.g. cxcr4，erbb4）使用CRISPR突变体鱼品系和新的外植体培养系统; 2） 确定冠状血管如何影响形态发生和GATA 4+的再生能力 心肌细胞在心肌扩张过程中使用克隆分析和 操纵Cxcl12-Cxcr4趋化因子信号传导。我们将进一步确定cxcl12b 表达受缺氧和Gata4调节。我们提出的研究将揭示 冠心病的发展原因。此外，阐明机制 斑马鱼潜在的心肌血管化将揭示潜在的治疗方法 接近人类。

Project Summary The coronary vasculature plays essential roles in maintaining a continuous supply of oxygen and nutrients to the heart. Coronary heart disease is a major cause of myocardial infarction and heart failure, which continues to be the leading cause of mortality worldwide. Despite its importance, the mechanisms that regulate coronary vascularization of the myocardium remain a major gap in our knowledge. We observed that during zebrafish heart development, coronary vessels form a close association with a specific subpopulation of cortical cardiomyocytes marked by the transcription factor Gata4. gata4+ cardiomyocytes follow the tracks of coronary endothelial cells when they emerge onto the surface of the juvenile zebrafish hearts. Furthermore, our preliminary data suggest that expression of the Cxcl12b chemokine, a critical angiogenic factor during zebrafish coronary vessel development, is increased in expanding gata4+ cardiomyocytes. Moreover, gata4+ cardiomyocytes fail to associate with coronary vessels in hearts lacking Cxcr4a, the receptor for Cxcl12b. Importantly, adult cxcr4a mutant zebrafish fail to regenerate after heart injury. We hypothesize that heart development occurs in two phases that are regulated by temporally distinct mechanisms: newly formed coronary endothelial cells provide instructive cues, such as paracrine factors, during the emerging phase to guide gata4+ cardiomyocytes when they emerge, while during the expanding phase, cxcl12b expression increases in gata4+ cardiomyocytes to attract coronary vessels that are essential for their morphogenesis/development and regeneration. We propose to 1) To determine how new coronary vessels guide gata4+ cardiomyocytes to populate the heart ventricle by analyzing differentially expressed candidate genes identified from RNAseq encoding secreted molecules (e.g. cxcr4, erbb4) using CRISPR mutant fish lines and a novel explant culture system; 2) To determine how coronary vessels affect morphogenesis and the regenerative capacity of gata4+ cardiomyocytes during myocardial expansion using multicolor clonal analysis and by manipulating Cxcl12-Cxcr4 chemokine signaling. We will further determine how cxcl12b expression is regulated by hypoxia and Gata4. Our proposed study will reveal potential developmental causes of coronary heart diseases. Furthermore, elucidation of the mechanisms underlying myocardial vascularization in zebrafish will shed light on potential therapeutic approaches for humans.