title: The Epicardium and the Development of the Atrioventricular Junction in the Murine Heart.
abstract: Insight into the role of the epicardium in cardiac development and regeneration has significantly improved over the past ten years. This is mainly due to the increasing availability of new mouse models for the study of the epicardial lineage. Here we focus on the growing understanding of the significance of the epicardium and epicardially-derived cells in the formation of the atrioventricular (AV) junction. First, through the process of epicardial epithelial-to-mesenchymal transformation (epiEMT), the subepicardial AV mesenchyme is formed. Subsequently, the AV-epicardium and epicardially-derived cells (EPDCs) form the annulus fibrosus, a structure important for the electrical separation of atrial and ventricular myocardium. Finally, the AV-EPDCs preferentially migrate into the parietal AV valve leaflets, largely replacing the endocardially-derived cell population. In this review, we provide an overview of what is currently known about the regulation of the events involved in this process.
authors.affiliation: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; lockharm@musc.edu (M.M.L.); phelpsal@musc.edu (A.L.P.).
authors.forename: Marie M
authors.initials: MM
authors.lastname: Lockhart
authors.affiliation: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; lockharm@musc.edu (M.M.L.); phelpsal@musc.edu (A.L.P.).
authors.forename: Aimee L
authors.initials: AL
authors.lastname: Phelps
authors.affiliation: Academic Medical Center, Heart Failure Research Center, Department of Anatomy, Embryology and Physiology, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands; m.j.vandenhoff@amc.uva.nl.
authors.forename: Maurice J B
authors.initials: MJ
authors.lastname: van den Hoff
authors.affiliation: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; lockharm@musc.edu (M.M.L.); phelpsal@musc.edu (A.L.P.).
authors.forename: Andy
authors.initials: A
authors.lastname: Wessels
keywords: annulus fibrosus; atrioventricular; cardiovascular; epicardium; heart; leaflets; sulcus; valves