Defining the developmental mechanisms of pericardium formation

项目摘要 心包膜是一个间皮囊，包裹心脏，以支持其发育和维持心脏功能。 随着时间的推移心脏内稳态。在整个心脏循环的过程中，心包作为细胞来源 形成各种心脏结构，使其成为心脏形态发生中的关键角色。然而， 关于它的发育起源，以及它如何在心脏发育，体内平衡， 和损伤后的再生。虽然早期的中皮层起源总体上只是最近才被详细描述 使用斑马鱼，心包由于其动态发育而特别难以研究， 缺乏遗传标记我们的实验室已经将中皮祖细胞定位到侧板中胚层， 转录因子Hand 2，并进一步将Hand 2功能与间皮和心包形成联系起来。 这些概念和技术的进步，在间皮生物学使我们能够调查如何心包和 在发育过程中，心脏结构聚集在一起形成单一的功能器官系统。我的扩展 这些数据表明，心包和心脏祖细胞是不同的祖细胞群体， 在胚胎形成过程中融合在一起。这项提案的目的是揭示发展中国家的 控制祖细胞模式进入心脏和心包的机制，并确定典型的 控制心包出现的Wnt信号。在目标1中，我将使用转基因斑马鱼 标记发育中的心脏和心包的线，体内延时成像，稳定的基因敲除， 心脏成分和多色谱系追踪报告，以检查细胞起源和动力学， 发育中的心包在目标2中，我将研究Hand 2和经典Wnt信号之间的相互作用， 通过记录Wnt靶基因在Hand 2突变斑马鱼中的表达动态， 使用CRISPR-Cas9诱变来突变Hand 2结合位点。总之，这个项目将 第一个完全描述心包发育过程并结合心脏和相互作用的 Hand 2和经典Wnt信号在控制心包发育中的作用。

PROJECT SUMMARY The pericardium is a mesothelial sac that encapsulates the heart to support its development and maintain cardiac homeostasis over time. Throughout the process of heart looping, the pericardium serves as a cell source to form various cardiac structures, making it a crucial player in heart morphogenesis. However, little is known about its developmental origins and how it acquires its unique properties in cardiac development, homeostasis, and regeneration post-injury. While early mesothelial origins overall have only been recently described in detail using the zebrafish, the pericardium has been particularly difficult to study due to its dynamic development and a lack of genetic markers. Our lab has mapped mesothelial progenitors to the lateral plate mesoderm expressing the transcription factor Hand2, and further linked Hand2 function to mesothelium and pericardium formation. These conceptual and technical advances in mesothelial biology enable us to investigate how pericardial and cardiac structures come together to form a single functional organ system during development. My expansion of this data suggests that pericardial and cardiac progenitors are distinct progenitor populations that later come together to fuse together during embryogenesis. The objective of this proposal is to uncover the developmental mechanisms governing progenitor patterning into the heart and pericardium and identify the role of canonical Wnt signaling that controls the pericardial emergence. In Aim 1, I will use a combination of transgenic zebrafish lines that label the developing heart and pericardium, in vivo time-lapse imaging, stable genetic knockdowns of cardiac components, and multi-color lineage tracing reporters to examine the cellular origins and dynamics of the developing pericardium. In Aim 2, I will investigate the interplay between Hand2 and canonical Wnt signaling by documenting the expression dynamics of Wnt targets in Hand2 mutant zebrafish, overexpressing Wnt components, and using CRISPR-Cas9 mutagenesis to mutate Hand2 binding sites. Together, this project will be the first to fully characterize how pericardial development proceeds and incorporates the heart and the interplay between Hand2 and canonical Wnt signaling in controlling pericardium development.