Directed Differentiation of Skin-Derived Precursors Into Functional Vascular Smooth Muscle Cells

Objective—The goal of this study was to characterize the factors and conditions required for smooth muscle cell (SMC)–directed differentiation of Sox2+ multipotent rat and human skin-derived precursors (SKPs) and to define whether they represent a source of fully functional vascular SMCs for applications in vivo. Methods and Results—We found that rat SKPs can differentiate almost exclusively into SMCs by reducing serum concentrations to 0.5% to 2% and plating them at low density. Human SKPs derived from foreskin required the addition of transforming growth factor-β1 or -β3 to differentiate into SMCs, but they did so even in the absence of serum. SMC formation was confirmed by quantitative reverse transcription–polymerase chain reaction, immunocytochemistry, and fluorescence-activated cell sorting, with increased expression of smoothelin-B and little to no expression of telokin or smooth muscle γ-actin, together indicating that SKPs differentiated into vascular rather than visceral SMCs. Rat and human SKP-...