Precardiac Organoids Form Two Heart Fields via Bmp/Wnt Signaling

The discovery of the first heart field (FHF) and the second heart field (SHF) led us to understand how cardiac lineages and structures arise during development. However, it remains unknown how they are specified. Here, we generate precardiac spheroids with pluripotent stem cells (PSCs) harboring GFP/RFP reporters under the control of FHF/SHF markers, respectively. GFP+ cells and RFP+ cells appear from two distinct areas and develop in a complementary fashion. Transcriptome analysis shows a high degree of similarities with embryonic FHF/SHF cells. Bmp and Wnt are among the most differentially regulated pathways, and gain- and loss-of-function studies reveal that Bmp specifies GFP+ cells and RFP+ cells via the Bmp/Smad pathway and Wnt signaling, respectively. FHF/SHF cells can be isolated without reporters by the surface protein Cxcr4. This study provides novel insights into understanding the specification of two cardiac origins, which can be leveraged for PSC-based modeling of heart field/chamber-specific disease. We sought to determine the cellular identities of PSC-derived GFP+ and RFP+ cells. To do this, GFP+ and RFP+ CPCs were FACS-isolated from the spheroids at day 5.5 or from Hcn4GFP; Tbx1Cre; Ai9 mouse embryos at E7.75 and subjected to RNA-sequencing.

第一心域（FHF）与第二心域（SHF）的发现，使我们得以解析胚胎发育过程中心脏谱系与心脏结构的形成机制。然而，二者的细胞特化机制至今仍未明确。本研究构建了分别受FHF与SHF标记基因调控、携带绿色荧光蛋白（GFP）与红色荧光蛋白（RFP）报告基因的多能干细胞（PSCs）预心球体。GFP阳性细胞与RFP阳性细胞起源于两个截然不同的区域，并以互补模式发育。转录组分析显示，这群细胞与胚胎来源的FHF/SHF细胞具有高度相似的转录特征。骨形态发生蛋白（Bmp）与Wnt信号通路是差异调控最为显著的通路之一；功能获得与功能丧失实验揭示，Bmp可通过Bmp/Smad通路特化GFP阳性细胞，而Wnt信号则可特化RFP阳性细胞。无需借助报告基因，即可通过表面蛋白Cxcr4分离得到FHF/SHF细胞。本研究为解析两种心脏起源的特化机制提供了全新视角，可用于构建基于PSCs的心脏域/腔室特异性疾病模型。为明确多能干细胞来源的GFP阳性与RFP阳性心肌前体细胞（CPCs）的细胞身份，我们于第5.5天从预心球体中，以及从胚胎发育第7.75天（E7.75）的Hcn4GFP; Tbx1Cre; Ai9小鼠胚胎中，通过荧光激活细胞分选（FACS）分离目标细胞并进行RNA测序。

搜集汇总

背景与挑战

背景概述

该数据集是一个关于小鼠心脏发育的研究，通过高通量测序分析前心脏球体中第一和第二心脏区域的分化机制。研究揭示了Bmp和Wnt信号通路在心脏细胞指定中的关键作用，并提供了93个样本的转录组数据，支持基于多能干细胞的心脏疾病建模。