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 SM γ-actin, together indicating that SKPs differentiated into vascular rather than visceral SMCs. Rat and human SKP-derived SMCs were able to contract in vitro and also wrap around and support new capillary and larger blood vessel formation in angiogenesis assays in vivo.
Conclusion—SKPs are Sox2+ progenitors that represent an attainable autologous source of stem cells that can be easily differentiated into functional vascular SMCs in defined serum-free conditions without reprogramming. SKPs represent a clinically viable cell source for potential therapeutic applications in neovascularization.
- Received December 17, 2010.
- Accepted July 27, 2011.
- © 2011 American Heart Association, Inc.