Sca-1⁺ cells express SMC markers in response to PDGF-BB. Sca-1⁺ cells were isolated with microbeads coupled with anti_Sca-1 antibodies and cultured in stem cell medium without PDGF-BB or in DMEM supplemented for 3 days with 10% FCS in the presence of PDGF-BB (10 ng/ml). (A) RNA was isolated, and RT-PCR was performed using the primers for SMC markers. (B) Adventitial Sca-1⁺ cells cultivated from SM-LacZ mice were cultured for 3 days with or without PDGF-BB, and developed with X-gal. (C) For immunofluorescent staining, cells were labeled with antibodies against α-actin (red), calponin (green), and smooth muscle myosin heavy chain (red) and counterstained with Hoechst 33258 (blue). SM-MHC, smooth muscle myosin heavy chain.