title: Factor-Xa-induced mitogenesis and migration require sphingosine kinase activity and S1P formation in human vascular smooth muscle cells.
abstract: OBJECTIVE
  Sphingosine-1-phosphate (S1P) is a cellular signalling lipid generated by sphingosine kinase-1 (SPHK1). The aim of the study was to investigate whether the activated coagulation factor-X (FXa) regulates SPHK1 transcription and the formation of S1P and subsequent mitogenesis and migration of human vascular smooth muscle cells (SMC).
  
  
  RESULTS
  FXa induced a time- (3-6 h) and concentration-dependent (3-30 nmol/L) increase of SPHK1 mRNA and protein expression in human aortic SMC, resulting in an increased synthesis of S1P. FXa-stimulated transcription of SPHK1 was mediated by the protease-activated receptor-1 (PAR-1) and PAR-2. In human carotid artery plaques, expression of SPHK1 was observed at SMC-rich sites and was co-localized with intraplaque FX/FXa content. FXa-induced SPHK1 transcription was attenuated by inhibitors of Rho kinase (Y27632) and by protein kinase C (PKC) isoforms (GF109203X). In addition, FXa rapidly induced the activation of the small GTPase Rho A. Inhibition of signalling pathways which regulate SPHK1 expression, inhibition of its activity or siRNA-mediated SPHK1 knockdown attenuated the mitogenic and chemotactic response of human SMC to FXa.
  
  
  CONCLUSIONS
  These data suggest that FXa induces SPHK1 expression and increases S1P formation independent of thrombin and that this involves the activation of Rho A and PKC signalling. In addition to its key function in coagulation, this direct effect of FXa on human SMC may increase cell proliferation and migration at sites of vessel injury and thereby contribute to the progression of vascular lesions.
authors: Institut für Pharmakologie, Abteilung Allgemeine Pharmakologie, Universitätsmedizin Greifswald, Felix-Hausdorff-Str. 3, Greifswald, Germany.
authors: Andreas
authors: A
authors: Böhm
authors: Anja
authors: A
authors: Flößer
authors: Swen
authors: S
authors: Ermler
authors: Anke C
authors: AC
authors: Fender
authors: Anja
authors: A
authors: Lüth
authors: Burkhard
authors: B
authors: Kleuser
authors: Karsten
authors: K
authors: Schrör
authors: Bernhard H
authors: BH
authors: Rauch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D015951:Factor Xa / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D008246:Lysophospholipids / Q000096:biosynthesis*; D008875:Middle Aged; D008938:Mitosis / Q000502:physiology; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000502:physiology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D044463:Receptor, PAR-1 / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000378:metabolism; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D020742:rhoA GTP-Binding Protein / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D015951:Factor Xa; D008246:Lysophospholipids; D017853:Phosphotransferases (Alcohol Group Acceptor); D011493:Protein Kinase C; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D013110:Sphingosine; D020742:rhoA GTP-Binding Protein; D000099157:Sphingosine Kinase; C066737:RHOA protein, human; C060506:sphingosine 1-phosphate
keywords: Atherosclerosis; Factor-Xa; Proliferation; Smooth muscle cells; Sphingosine kinase-1