title: High glucose enhances thrombin responses via protease-activated receptor-4 in human vascular smooth muscle cells.
abstract: OBJECTIVE
  Diabetes is associated with vascular remodeling and increased thrombin generation. Thrombin promotes vascular smooth muscle cell (SMC) mitogenesis and migration via protease-activated receptors (PAR)-1, PAR-3, and PAR-4. We investigated the effect of high glucose on expression and function of vascular thrombin receptors.
  
  
  RESULTS
  In human vascular SMCs, high glucose (25 versus 5.5 mmol/L) induced a rapid and sustained increase in PAR-4 mRNA, protein, and cell surface expression. PAR-1 and PAR-3 expression were not changed. High glucose pretreatment (48 hours) enhanced thrombin or PAR-4-activating peptide but not PAR-1-activating peptide evoked intracellular calcium mobilization, migration, and tumor necrosis factor α gene expression. This enhancement of thrombin-stimulated migration and gene expression by high glucose was abolished by endogenous PAR-4 knockdown. PAR-4 regulation was prevented by inhibition of protein kinase (PK)C-β and -δ isoforms or nuclear factor (NF)κB. Nuclear translocation of NFκB in high glucose-stimulated SMCs led to PKC-dependent NFκB binding to the PAR-4 promoter in a chromatin immunoprecipitation assay. Furthermore, in situ hybridization and immunohistochemistry confirmed high abundance of PAR-4 in human diabetic vessels as compared with nondiabetic vessels.
  
  
  CONCLUSIONS
  High glucose enhances SMC responsiveness to thrombin through transcriptional upregulation of PAR-4, mediated via PKC-β, -δ, and NFκB. This may play an important role in the vascular complications of diabetes.
authors.affiliation: Institut für Pharmakologie und Klinische Pharmakologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
authors.forename: Seema
authors.initials: S
authors.lastname: Dangwal
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Rauch
authors.forename: Thomas
authors.initials: T
authors.lastname: Gensch
authors.forename: Luru
authors.initials: L
authors.lastname: Dai
authors.forename: Ellen
authors.initials: E
authors.lastname: Bretschneider
authors.forename: Christina Francisca
authors.initials: CF
authors.lastname: Vogelaar
authors.forename: Karsten
authors.initials: K
authors.lastname: Schrör
authors.forename: Anke C
authors.initials: AC
authors.lastname: Rosenkranz
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002465:Cell Movement; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D003925:Diabetic Angiopathies / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D064546:Protein Kinase C beta; D051745:Protein Kinase C-delta / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism; D018179:Receptors, Thrombin / Q000235:genetics / Q000378:metabolism*; D013917:Thrombin / Q000378:metabolism*; D013997:Time Factors; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; D014409:Tumor Necrosis Factor-alpha; C105295:protease-activated receptor 3; C497258:PRKCD protein, human; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051745:Protein Kinase C-delta; D013917:Thrombin; D005947:Glucose; C112908:protease-activated receptor 4; D002118:Calcium