The Role of Aplnr Signaling in the Developmental Regulation of Mesenchymal Stem Cell Differentiation from Human Pluripotent Stem Cells

Stem cells are invaluable resources for personalized medicine. Mesenchymal stem cells (MSCs) have received great attention as therapeutic tools due to being a safe, ethical, and accessible option with immunomodulatory and controlled differentiation properties. Apelin receptor (Aplnr) signaling is reported to be involved in biological events, including gastrulation, mesoderm migration, proliferation of MSCs. However, the knowledge about the exact role and mechanism of Aplnr signaling during mesoderm and MSCs differentiation is still primitive. The current study aims to unveil the role of Aplnr signaling during mesoderm and MSC differentiation from pluripotent stem cells (PSCs) through peptide/small molecule activation, overexpression, knock down or CRISPR/Cas9 mediated knock out of the pathway components. Morphological changes, gene and protein expression analysis, including antibody array, LC/MS, mRNA/miRNA sequencing, reveal that Aplnr signaling promotes mesoderm commitment possibly via EGFR and TGF-beta signaling pathways and enhances migration of cells during mesoderm differentiation. Moreover, Aplnr signaling positively regulates MSCs differentiation from hPSCs and increases MSC characteristics and differentiation capacity by regulating pathways, such as EGFR, TGF beta, Wnt, PDGF, and FGF. Osteogenic, chondrogenic, adipogenic, and myogenic differentiations are significantly enhanced with Aplnr signaling activity. This study generates an important foundation to generate high potential MSCs from PSCs to be used in personalized cell therapy. Human pluripotent stem cell (hPSC) derived mesodermal progeniors, as a major source of MSCs, have a high proliferation and differentiation capacity in culture. Activation of Apelin receptor (Aplnr) signaling at mesoderm stages upregulates certain molecular pathways and important genes including Bra, Flk-1, and PDGFR alpha. These pathways regulates mesenchymal stem cell differentiation in culture upon activation of Aplnr signaling.image