title: Tissue factor-thrombin signaling enhances the fibrotic activity of myofibroblasts in systemic sclerosis through up-regulation of endothelin receptor A.
abstract: OBJECTIVE
  The extrinsic coagulation cascade is involved in the fibrotic process, via thrombin-dependent induction of CCN2 (connective tissue growth factor) expression. Given the previously reported activation of the coagulation system in systemic sclerosis (SSc), we undertook the present study to investigate the involvement of cross-talk between the tissue factor (TF)-thrombin axis and endothelin 1 (ET-1) signaling in the fibrotic activity of SSc.
  
  
  METHODS
  Human colonic myofibroblasts (HCMFs) from 6 patients with SSc and gastrointestinal symptoms and from 6 control subjects were isolated and cultured under various conditions. Messenger RNA and protein levels of TF, CCN2, and endothelin receptor A (ET(A) ) were investigated. Collagen production and migratory activity of HCMFs were further assessed.
  
  
  RESULTS
  HCMFs from SSc patients demonstrated increased basal CCN2 production, collagen deposition, and migration rate, in a thrombin-dependent manner. Increased TF expression was also observed in SSc HCMFs. Subsequent activation of the extrinsic coagulation system resulted in thrombin-dependent enhancement of ET(A)  expression. ET(A)  overexpression led to further increases in both TF expression and fibrotic activity in HCMFs. Moreover, inhibition of ET-1 signaling by bosentan abolished the TF-mediated fibrotic capacity of HCMFs.
  
  
  CONCLUSIONS
  Tissue factor-thrombin signaling is involved in the increased fibrotic activity of HCMFs from patients with SSc. Moreover, the up-regulation of ET(A)  expression by thrombin and the effect of ET-1 in the induction of TF expression indicate an amplification loop for enhanced collagen deposition. Therapeutic interventions targeting the extrinsic coagulation system or ET-1 signaling may provide clinical benefit by breaking this vicious circle.
authors.affiliation: Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Akrivi
authors.initials: A
authors.lastname: Chrysanthopoulou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mitroulis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kambas
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Skendros
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kourtzelis
authors.forename: Stergios
authors.initials: S
authors.lastname: Vradelis
authors.forename: George
authors.initials: G
authors.lastname: Kolios
authors.forename: Spyros
authors.initials: S
authors.lastname: Aslanidis
authors.forename: Michael
authors.initials: M
authors.lastname: Doumas
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Ritis
mesh_terms: D002465:Cell Movement; D049109:Cell Proliferation; D024042:Collagen Type I / Q000378:metabolism; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D005355:Fibrosis; D006801:Humans; D058628:Myofibroblasts / Q000378:metabolism* / Q000473:pathology; D044022:Receptor, Endothelin A / Q000378:metabolism*; D044463:Receptor, PAR-1 / Q000378:metabolism; D012595:Scleroderma, Systemic / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction; D013917:Thrombin / Q000378:metabolism*; D013925:Thromboplastin / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; D044022:Receptor, Endothelin A; D044463:Receptor, PAR-1; D055513:Connective Tissue Growth Factor; D013925:Thromboplastin; D013917:Thrombin