Single-cell transcriptomics reveals chemotaxis mediated intra-organ crosstalk during cardiogenesis [ChIP-seq]

We used single-cell RNA-seq to reconstruct differentiation paths of cardiac progenitors in two sequential waves during early heart development. Further analysis identified six major cell types and multiple differentiation trajectories of cardiac progenitors derived from distinct heart fields. We also constructed TF regulatory networks controlling SHF CPC differentiation. Interlineage crosstalk through signaling pathways and chemotactic guidance played a potent role in SHF CPC deployment. The mechanisms regulating SHF CPC migration and differentiation was further confirmed by Nkx2-5 enhancer knock out. Our work provides a cardiac lineage hierarchy and new insights into SHF CPC development. Mechanistically, NKX2-5 directly bound the Cxcr2 genomic locus and activated its transcription. Overall design: We performed NKX2-5 ChIP-seq using an Nkx2-5 allele in which the endogenous gene has been modified to incorporate FLAG and bio (flbio) epitope tags, where bio is specifically biotinylated by the enzyme BirA (He et al. 2014; Zhou et al. 2017). SHF (largely SpM and pharyngeal mesoderm) and HT regions were separately micro-dissected for a modified bioChIP-seq in Nkx2-5flbio/+::Rosa26BirA/+ mouse embryos at E8.25-8.75.