title: [AP-1 mediated signal transduction in thrombin-induced regulation of PAL-1 expression in human mesangial cells].
abstract: OBJECTIVE
  To evaluate activator protein-1 (AP-1) mediated mechanisms in thrombin-induced qlasminogen activator inhibitor-1 (PAI-1) expression in cultured human glomerular mesangial cells (MCs).
  
  
  METHODS
  Electrophoretic mobility shift assay (EMSA) was employed to assess AP-1 DNA-binding activity, and Western blot hybridization was used for quantification of c-fos and c-jun, two subunits of AP-1 dimers. PAI-1 activity and mRNA expression were analysed by the fibrin plate assay and Northern hybridization, respectively.
  
  
  RESULTS
  Thrombin concentration enhanced PAI-1 activity in the supernatant and stimulated PAI-1 mRNA expression in cultured MCs. PAI-1 activity was blocked by hirudin, a specific inhibitor of thrombin. Further study demonstrated that thrombin promoted AP-1 DNA-binding activity but exerted little effect on c-fos or c-jun. Curcumin (AP-1 inhibitor), staurosporine (PKC inhibitor), and genistein (PTK inhibitor) all reduced AP-1-mediated PAI-1 mRNA expression induced by thrombin in cultured MCs.
  
  
  CONCLUSIONS
  The present study indicates that in cultured human MCs, thrombin stimulates PAI-1 expression through an AP-1 signal pathway, which may be mediated by PKC and PTK.
authors.affiliation: Department of Nephrology, General Hospital of Chinese PLA, Beijing 100853, China. xmchen@public.bta.net.cn
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.forename: Q
authors.initials: Q
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Ye
authors.forename: B
authors.initials: B
authors.lastname: Fu
authors.forename: L
authors.initials: L
authors.lastname: Yu
mesh_terms: D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects*; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D011493:Protein Kinase C / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction; D013917:Thrombin / Q000494:pharmacology*; D018808:Transcription Factor AP-1 / Q000502:physiology*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D013917:Thrombin