Diverse contribution of amniogenic somatopleural cells to cardiovascular development: With special reference to thyroid vasculature

Abstract

Background:The somatopleure serves as the primordium of the amnion, an extraembryonic membrane surrounding the embryo. Recently, we have reported that amniogenic somatopleural cells (ASCs) not only form the amnion but also migrate into the embryo and differentiate into cardiomyocytes and vascular endothelial cells. However, detailed differentiation processes and final distributions of these intra-embryonic amniogenic somatopleural cells (hereafter referred to as iASCs) remain largely unknown.Results: By quail-chick chimera analysis, we here show that iASCs differentiate into various cell types including cardiomyocytes, smooth muscle cells, cardiac interstitial cells, and vascular endothelial cells. In the pharyngeal region, they distribute selectively into the thyroid gland and differentiate into vascular endothelial cells to form intra-thyroid vasculature.Explant culture experiments indicated sequential requirement of FGF and VEGF signaling for endothelial differentiation of iASCs. Single-cell transcriptome analysis further revealed heterogeneity and the presence of hemangioblast-like cell population within ASCs, with a switch from FGF to VEGF receptor gene expression. Conclusion:The present study demonstrates novel roles of amniogenic somatopleural cells especially in heart and thyroid development. It will provide a novel clue for understanding the cardiovascular development of amniotes from embryological and evolutionary perspectives.

From pumps to pipes: A special issue on mechanisms of cardiovascular development

“…However, they can also contribute to the embryo. Haneda et al, 7 use quail chick chimera analysis to show that intraembryonic ASCs in pharyngeal regions contribute to the developing vasculature of the thyroid. They use single‐cell sequencing and explants of ASCs to suggest the presence of hemangioblast‐like cells that respond to FGF and VEGF in the early but not late amnion.…”