Genetic Lineage Traces the Differentiation Fate of Epicardial Cells during Heart Development

Abstract

Objective: The genetic lineage tracing method was used to examine the Epithelial-Mesenchymal Transition (EMT) process and the contribution of epicardial cells to mesenchymal cells at various stages of fetal heart development. Methods: In Wt1-CreER; R26-tdTomato transgenic mice, tamoxifen was utilized to promote the tagging of epicardial cells with tdTomato fluorescence at E10. At E11.5, E12.5, and E16.5, embryonic hearts were harvested and photographed using confocal fluorescence microscopy and stereomicroscopy. Results: According to the findings, the tdTomato+ cells at E11.5 were still in the epicardium and had not yet moved into the myocardium. Epicardial cells began to separate from the epicardium and give rise to epicardial-derived cells at embryonic day 12.5 (E12.5). On the valve primordium, fibroblasts generated from epicardium have been found. By E16.5, many epicardial cells had moved into the myocardium and formed fibroblasts, mesenchymal cells, vascular smooth muscle cells, as well as migrated into the ventricular septum and valves, contributing to their growth and creation. Conclusions: The contribution of epicardial cells to mesenchymal cells during development is shown by genetic lineage tracing, opening up possibilities and offering references for creating relevant treatment approaches based on epicardial cells.