Activation of transforming growth factor-β1 by thrombin via integrins αvβ1, αvβ3, and αvβ5 in buccal fibroblasts: Suppression by epigallocatechin-3-gallate

Head Neck. 2017 Jul;39(7):1436-1445. doi: 10.1002/hed.24791. Epub 2017 May 2.

Abstract

Background: Transforming growth factor-beta (TGF-β) plays a central role in the pathogenesis of oral submucous fibrosis (OSF). Thrombin is a key player in tissue repair, inflammation, and fibrosis after injury.

Methods: Effects of thrombin on activated-TGF-β1 levels, Smad3 phosphorylation, and connective tissue growth factor (CTGF/CCN2) synthesis in primary human buccal mucosal fibroblasts (BMFs) were assessed by enzyme-linked immunosorbent assay or Western blot analysis.

Results: Thrombin and protease-activated receptor-1 (PAR-1) agonist induced TGF-β1 activation and Smad3 phosphorylation. Pretreatment with TGF-β-neutralizing antibody completely inhibited thrombin-induced CCN2 synthesis. Neutralizing antibodies to integrin αv, β1, αvβ3, αvβ5, and Rho-associated coiled-coil forming protein kinase (ROCK) inhibitor Y27632 completely blocked thrombin-induced TGF-β1 activation, Smad3 phosphorylation, and CCN2 synthesis. Epigallocatechin-3-gallate (EGCG) dose-dependently inhibited thrombin-induced TGF-β1 activation.

Conclusion: Thrombin induces αvβ1, αvβ3, and αvβ5 integrins-mediated TGF-β1 activations via ROCK signaling. EGCG inhibits thrombin-induced CCN2 synthesis in BMFs by suppressing latent TGF-β1 activation.

Keywords: epigallocatechin-3-gallate (EGCG); fibroblast; oral submucous fibrosis; thrombin; transforming growth factor-beta (TGF-β).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western / methods
  • Catechin / analogs & derivatives
  • Catechin / metabolism
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Humans
  • Integrin alphaVbeta3 / drug effects
  • Integrin alphaVbeta3 / metabolism*
  • Mouth Mucosa / metabolism
  • Mouth Mucosa / pathology
  • Oral Submucous Fibrosis / metabolism
  • Oral Submucous Fibrosis / pathology*
  • Receptors, Vitronectin / metabolism*
  • Sensitivity and Specificity
  • Thrombin / pharmacology*
  • Transforming Growth Factor beta1 / drug effects
  • Transforming Growth Factor beta1 / metabolism*

Substances

  • Integrin alphaVbeta3
  • Receptors, Vitronectin
  • Transforming Growth Factor beta1
  • integrin alphaVbeta5
  • integrin alphavbeta1
  • Catechin
  • epigallocatechin gallate
  • Thrombin