Type V Collagen Directs the Differentiation of iPSCs into Valvular Endothelial‐Like Cells

Valvular endothelial cells (VECs) derived from induced pluripotent stem cells (iPSCs) serve as a promising source for cardiovascular research, yet their application is limited by suboptimal differentiation efficiency and functional immaturity. The extracellular matrix (ECM) influences stem cell differentiation, with the valvular ECM being unique compared to other tissues, and our understanding of its role in VECs differentiation is limited. The proteomic analysis comparing the protein composition of decellularized human heart valve ECM (dhECM) and Matrigel found that type V collagen (Col V) was uniquely present in dhECM and localized beneath the endothelium in the ventricular layer of valves. Subsequent investigations into the role of Col V in the differentiation of iPSC-derived valvular endothelial-like cells (iVECs) demonstrated that Col V significantly enhanced differentiation efficiency from 18.2% to a peak of 69.6%. Moreover, Col V promoted the proliferation, adhesion, migration, tube formation, and low-density lipoprotein (LDL) uptake functions of iVECs in vitro, showing a closer alignment with the functionality of primary VECs. Overall, this study indicates that Col V directs the differentiation of iPSCs into valvular endothelial-like cells with improved differentiation efficiency and functionality, which is instrumental for the development and application of tissue-engineered heart valves, drug screening, and the future of regenerative medicine.