EXPERIMENTAL and MOLECULAR MEDICINE, Vol. 44, No. 2, 159-166, February 2012 Simvastatin inhibits sphingosylphosphorylcholine-induced differentiation of human mesenchymal stem cells into smooth muscle cells Kyung Hye Kim1, Young Mi Kim1, Mi Jeong Lee1, Hyun-Chang Ko3, Moon-Bum Kim3 and Jae Ho Kim1,2,4,5 1Medical Research Center for Ischemic Tissue Regeneration 2Department of Physiology 3Department of Dermatology School of Medicine Pusan National University Yangsan 626-870, Korea 4Research Institute of Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan 626-770, Korea 5Corresponding author: Tel, 82-51-510-8073; Fax, 82-51-510-8076; E-mail, jhkimst@pusan.ac.kr http://dx.doi.org/10.3858/emm.2012.44.2.011 Accepted 25 November 2011 Available Online 30 November 2011 Abbreviations: FPP, farnesylpyrophosphate; GGPP, ger- anylgeranylpyrophosphate; hASCs, human adipose tissue-de- rived mesenchymal stem cells; HMG-CoA, 3-hydroxy-3-methyl- glutaryl coenzyme A; MSCs, mesenchymal stem cells; SMCs, smooth muscle cells; SPC, sphingosylphosphorylcholine; sta- tins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase in- hibitors Abstract Sphingosylphosphorylcholine (SPC) induces differ- entiation of human adipose tissue-derived mesen- chymal stem cells (hASCs) into smooth muscle-like cells expressing α-smooth muscle actin (α-SMA) via transforming growth factor-β1/Smad2- and RhoA/Rho kinase-dependent mechanisms. 3-Hydroxy-3-methyl- glutaryl-coenzyme A reductase inhibitors (statins) have been known to have beneficial effects in the treat- ment of cardiovascular diseases. In the present study, we examined the effects of simvastatin on the SPC-in- duced α-SMA expression and Smad2 phosphorylation in hASCs. Simvastatin inhibited the SPC-induced α-SMA expression and sustained phosphorylation of Smad2 in hASCs. SPC treatment caused RhoA activa- tion via a simvastatin-sensitive mechanism. The SPC-induced α-SMA expression and Smad2 phos- phorylation were abrogated by pretreatment of the cells with the Rho kinase inhibitor Y27632 or over- expression of a dominant negative RhoA mutant. Furthermore, SPC induced secretion of TGF-β1 and pretreatment with either Y27632 or simvastatin in- hibited the SPC-induced TGF-β1 secretion. These re- sults suggest that simvastatin inhibits SPC-induced differentiation of hASCs into smooth muscle cells by attenuating the RhoA/Rho kinase-dependent activa- tion of autocrine TGF-β1/Smad2 signaling pathway. Keywords: cell differentiation; mesenchymal stem cells; myocytes, smooth muscle; rhoA GTP-binding protein; simvastatin; sphingosine phosphorylcholine; transforming growth factor β1 Introduction Smooth muscle cells (SMCs) play an important role in angiogenesis, vessel maintenance, and reg- ulation of blood pressure. SMCs exhibit a con- tractile phenotype characterized by high expression of specific contractile proteins, including α-SMA, calponin-1, SM22α, smoothelin, h-caldesmon, and smooth muscle myosin heavy chain (Shanahan et al., 1993; Owens et al., 2004). The phenotypic ex- pression of SMCs is implicated in vascular devel- opment as well as in a variety of cardiovascular diseases, including hypertension and athero- sclerosis (Liu et al., 2004; Owens et al., 2004). Mesenchymal stem cells (MSCs) have a self-re- newal capacity, long-term viability, and potential to differentiate into cells of diverse lineages, such as adipogenic, osteogenic, chondrogenic, and myo- genic lineages (Pittenger and Martin, 2004; Caplan, 2007; Chamberlain et al., 2007; Prockop et al., 2010). Bone marrow-derived MSCs have been shown to differentiate to smooth muscle cells (SMCs) in re- sponse to transforming growth factor-β (TGF-β) Copyright ⓒ 2012 by the The Korean Society for Biochemistry and Molecular Biology This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.