Live-imaging reveals Coordinated Cell Migration and Cardiac Fate Determination during Mammalian Gastrulation

Abstract

AbstractHeart development involves the specification of distinct sets of cardiac progenitors at various times and locations during ontogeny. Here, we used live imaging in mice from the initiation of gastrulation to heart tube formation stages to investigate the origin and migratory paths of cardiac progenitors. We tracked individual mesodermal cells, reconstructing the lineage tree of the cells and fates for up to four generations. Our findings revealed independent unipotent progenitors originating at specific times that exclusively contribute to the left ventricle/atrioventricular canal (LV/AVC) or atrial myocytes. LV/AVC progeny differentiated into myocytes early, forming the cardiac crescent, while atrial progenitors differentiated later and contributed to the venous poles of the heart tube during morphogenesis. We also identified short-lived bipotent and tripotent mesodermal progenitors that contribute to a diverse array of mesodermal cell types, illustrating early plasticity during gastrulation. Sister cells generated by multipotent progenitors dispersed more and adopted more diverse migratory trajectories within the anterior mesoderm space than those from unipotent progenitors. Together the data reveal the regulation of individual cell directionality and cardiac fate allocation within the seemingly unorganised migratory pattern of mesoderm cells.