title: A Rho kinase/myocardin-related transcription factor-A-dependent mechanism underlies the sphingosylphosphorylcholine-induced differentiation of mesenchymal stem cells into contractile smooth muscle cells.
abstract: Sphingosylphosphorylcholine (SPC) induces differentiation of human adipose tissue-derived mesenchymal stem cells (hADSCs) to smooth muscle cells (SMCs). In the present study, we characterized contractile and ion channel properties of SMCs differentiated from hADSCs (hADSC-SMCs) as a result of SPC treatment, and we investigated the molecular mechanisms involved in the SPC-induced differentiation. Using in vitro collagen gel lattice contraction and whole cell patch clamp, we showed that the hADSC-SMCs expressed functional L-type voltage-gated Ca2+ channels and contractile activities in response to KCl, carbachol, and the L-type Ca2+ channel opener Bay K8644, whereas the L-type Ca2+ channel blocker nifedipine abrogated the contractility of hADSC-SMCs. Furthermore, hADSC-SMCs expressed functional big conductance Ca2+-activated K+ (BK(Ca)) channels, and the BK(Ca) channel blocker iberiotoxin potentiated the Bay K8644-stimulated contractility of the hADSC-SMCs, indicating that these cells exhibited SMC-like contractile characteristics. SPC activated RhoA in hADSCs and pretreatment with the Rho kinase inhibitor Y27632 or by overexpression of dominant-negative mutants of RhoA or Rho kinase completely abrogated the SPC-induced differentiation of hADSCs into SMCs. SPC also increased the expression levels of myocardin-related transcription factor (MRTF)-A, a transcription factor involved in smooth muscle differentiation, in hADSCs. Small interference RNA-mediated depletion of endogenous MRTF-A abolished the SPC-induced differentiation of hADSCs into SMCs. Furthermore, SPC promoted nuclear translocation of MRTF-A, and pharmacological inhibition of Rho kinase blocked this effect. These results suggest that SPC induced differentiation of hADSCs into contractile SMCs through a mechanism involving RhoA/Rho kinase-dependent nuclear translocation of MRTF-A.
authors.affiliation: Department of Physiology, Pusan National University College of Medicine, Busan 602-739, Republic of Korea.
authors.forename: Eun Su
authors.initials: ES
authors.lastname: Jeon
authors.forename: Won Sun
authors.initials: WS
authors.lastname: Park
authors.forename: Mi Jeong
authors.initials: MJ
authors.lastname: Lee
authors.forename: Young Mi
authors.initials: YM
authors.lastname: Kim
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Kim
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000502:physiology; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000502:physiology*; D010767:Phosphorylcholine / Q000031:analogs & derivatives*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology; D054460:rho-Associated Kinases / Q000502:physiology*; D000099251:Myocardin
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion; D010767:Phosphorylcholine; D013110:Sphingosine; D015534:Trans-Activators; D054460:rho-Associated Kinases; D000099251:Myocardin; C431575:MRTFA protein, human; C005356:sphingosine phosphorylcholine