Generation of the epicardial lineage from human pluripotent stem cells

Abstract

The epicardium supports cardiomyocyte proliferation early in development and provides fibroblasts and vascular smooth muscle cells to the developing heart. The epicardium has been shown to play an important role during tissue remodeling after cardiac injury, making access to this cell lineage necessary for the study of regenerative medicine. Here we describe the generation of epicardial lineage cells from human pluripotent stem cells by stage-specific activation of the BMP and WNT signaling pathways. These cells display morphological characteristics and express markers of the epicardial lineage, including the transcription factors WT1 and TBX18 and the retinoic acid–producing enzyme ALDH1A2. When induced to undergo epicardial-tomesenchymal transition, the cells give rise to populations that display characteristics of the fibroblast and vascular smooth muscle lineages. These findings identify BMP and WNT as key regulators of the epicardial lineage in vitro and provide a model for investigating epicardial function in human development and disease.

<b>Tbx18-positive cells differentiated from murine ES cells serve as proepicardial progenitors to give rise to vascular smooth muscle cells and fibr</b><b>oblasts </b>

“…Taken together, Tbx18-positive cells give rise to vascular SMCs and fibroblasts through EMT in vitro. Witty et al reported that the basic fibroblast growth factor and transforming growth factor beta were important for differentiation of epicardial cells derived from human iPS cells into vascular SMCs and fibroblasts (23). Whether Tbx18-EGFP-positive cells need these growth factors is the future research direction.…”

“…Epicardium is localized on the outer surface of the heart and composes the heart together with the inner endocardium and the central myocardium. Epicardium contributes not only to proper embryonic development of the heart but also to cardiac repair during a disease (23). This indicates that progenitor cells of epicardium could be one of the cell sources for cell-based regenerative medicine in patients with heart diseases.…”

“…A recent study have reported that PE cells are composed of two cell lineages, one expressing T-box18 (Tbx18) and Wilms Tumor-1 (WT1), and the other expressing Scx and Semad3 (9). A lineage tracing study in mice showed that Tbx18-positive cells gave rise to cardiac myocytes, fibroblasts and coronary vascular SMCs (23). A similar study in mice showed that the PE cells expressing Tbx18 and WT1 gave rise to SMCs, cardiomyocytes and fibroblasts but not to endothelial cells (3,24).…”

Ten years of induced pluripotency: from basic mechanisms to therapeutic applications

“…The basis of this strategy comes from the lab of Gordon Keller (McEwen Centre for Regenerative Medicine, Canada), who spoke about his aim to produce all the different cell types present in the adult heart via directed differentiation. Keller stressed the importance of replicating in vivo developmental processes to achieve this aim, and showed how the derivation of atrial and ventricle cardiomyocytes, pacemaker cells and epicardial cells can be simplified to controlling the expression of BMP and Wnt at specific time points from the mesoderm stage (Witty et al, 2014).…”

Differentiation and Application of Induced Pluripotent Stem Cell–Derived Vascular Smooth Muscle Cells

“…And more specifically proepicardial VSMCs are generated from hPSCs by precisely controlled administration of BMP2, 19 which crucially require activation of the BMP and Wnt signaling pathways to induce epithelial to mesenchymal transition for further specification toward the VSMC phenotype. 20 Meanwhile, neuroectoderm-derived VSMC generation requires FGF2 and activin inhibition, whereas paraxial mesoderm-derived VSMC generation requires initial BMP4 signaling with FGF2 and PI3K (phosphatidylinositol-4,5-bisphosphate 3-kinase) inhibition 21 ( Figure 1). Because iPSCs are derived from terminally differentiated cells, it is important to consider cell lineage commitment pathways during differentiation.…”