Novel Insights into the Molecular Mechanisms Governing Embryonic Epicardium Formation.

Abstract

The embryonic epicardium originates from the proepicardium, an extracardiac primordium constituted by a cluster of mesothelial cells. In early embryos, the embryonic epicardium is characterized by a squamous cell epithelium resting on the myocardium surface. Subsequently, it invades the subepicardial space and thereafter the embryonicmyocardiumbymeans of an epithelial–mesenchymal transition.Within the myocardium, epicardial-derived cells present multilineage potential, later differentiating into smoothmuscle cells and contributing both to coronary vasculature and cardiac fibroblasts in themature heart. Over the last decades, we have progressively increased our understanding of those cellular and molecular mechanisms driving proepicardial/embryonic epicardium formation. This study provides a state-of-the-art review of the transcriptional and emerging post-transcriptional mechanisms involved in the formation and differentiation of the embryonic epicardium.