title: PAR-1 mediates the thrombin-induced mesothelial cell overproduction of VEGF and PAI-1.
abstract: OBJECTIVE
  Thrombin mediates an excess in the production of neoangiogenetic (VEGF) and profibrotic (PAI-1) factors in human peritoneal mesothelial cells (HMC). The mechanisms leading to this overproduction have not been elucidated so far; in the context of peritoneal dialysis it can result in impaired peritoneal membrane function.
  
  
  OBJECTIVE
  This study was performed to evaluate the presence of the thrombin receptor protease-activated receptor-1 (PAR-1) in HMC and to characterize its function in the thrombin-dependent effects mentioned above.
  
  
  METHODS
  All experiments were performed using cultured primary HMC. Real-Time PCR and Western Blot were used to evaluate PAR-1; ELISA and Real-Time PCR were employed to examine PAR-1 effects on target mediators.
  
  
  RESULTS
  We found that cultivated primary HMC show a basal presence of PAR-1. Stimulation with IL-1β induced an increase of the mesothelial PAR-1 expression whereas stimulation with glycosilated human serum albumin or the ligand thrombin itself resulted in decreased PAR-1 expression. Stimulation with the specific PAR-1 ligand TFLLR-NH(2) caused increased VEGF and PAI-1 levels similar to stimulation with thrombin, whereas preincubation with PAR-1 blocking antibodies ATAP2 and WEDE15 attenuated the thrombin-induced overproduction of VEGF and PAI-1.
  
  
  CONCLUSIONS
  HMC express PAR-1 and the receptor is involved in thrombin effects on these cells. These findings may be a basis for pharmacological prevention of neoangiogenesis and adhesions in the context of peritoneal dialysis and peritonitis.
authors.affiliation: Medizinische Klinik und Poliklinik IV, Klinikum der Universitaet Muenchen, Munich - Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Belling
authors.forename: Andrea
authors.initials: A
authors.lastname: Ribeiro
authors.forename: Markus
authors.initials: M
authors.lastname: Wörnle
authors.forename: Roland
authors.initials: R
authors.lastname: Ladurner
authors.forename: Thomas
authors.initials: T
authors.lastname: Mussack
authors.forename: Thomas
authors.initials: T
authors.lastname: Sitter
authors.forename: Matthias
authors.initials: M
authors.lastname: Sauter
mesh_terms: D019138:Antibodies, Blocking / Q000494:pharmacology; D015153:Blotting, Western; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism*; D017127:Glycation End Products, Advanced; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D010537:Peritoneum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D061251:Primary Cell Culture; D060888:Real-Time Polymerase Chain Reaction; D044463:Receptor, PAR-1 / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012709:Serum Albumin / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D000093423:Glycated Serum Albumin; D010975:Platelet Aggregation Inhibitors
chemical_list: D019138:Antibodies, Blocking; D017127:Glycation End Products, Advanced; D053583:Interleukin-1beta; D009842:Oligopeptides; C462999:PAR-1-activating peptide; D017395:Plasminogen Activator Inhibitor 1; D044463:Receptor, PAR-1; C051321:SERPINE1 protein, human; D012709:Serum Albumin; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D013917:Thrombin; D000093423:Glycated Serum Albumin; D010975:Platelet Aggregation Inhibitors