Discovery of a chemical small molecule inducing umbilical cord mesenchymal stem cell differentiation to vascular endothelial cells.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) have emerged as promising candidates for clinical applications in vascular disease therapy and in the in vitro modeling of vascular regeneration. However, the translational potential of hUC-MSCs requires direct differentiation into functional vascular lineage cells, particularly vascular endothelial cells (VECs) and endothelial progenitor cells (EPCs). A critical challenge is the lack of reliable sources that yield sufficient quantities of mature VECs/EPCs for therapeutic purposes. To address this limitation, we established an efficient protocol for generating VECs from hUC-MSCs. Preconditioning hUC-MSCs using small molecules with cytoprotective properties can enhance their potential for use in cell-based therapeutics. Through systematic screening, we identified CPP as a novel small chemical molecule that effectively induces the endothelial differentiation of hUC-MSCs. Remarkably, our CPP-based induction protocol achieved > 90% conversion to functionally competent VECs within 5 days, as evidenced by both in vitro assays and in vivo functional validation. Single-cell RNA sequencing (scRNA-seq) analysis further delineated the differentiation trajectory and confirmed the acquisition of endothelial-specific molecular signatures during lineage commitment. These findings establish CPP as a potent inducer of rapid endothelial differentiation, and provide mechanistic insights into stem cell fate determination.