Mechanical tension increases CCN2/CTGF expression and proliferation in gingival fibroblasts via a TGFβ-dependent mechanism

PLoS One. 2011;6(5):e19756. doi: 10.1371/journal.pone.0019756. Epub 2011 May 17.

Abstract

Unlike skin, oral gingival do not scar in response to tissue injury. Fibroblasts, the cell type responsible for connective tissue repair and scarring, are exposed to mechanical tension during normal and pathological conditions including wound healing and fibrogenesis. Understanding how human gingival fibroblasts respond to mechanical tension is likely to yield valuable insights not only into gingival function but also into the molecular basis of scarless repair. CCN2/connective tissue growth factor is potently induced in fibroblasts during tissue repair and fibrogenesis. We subjected gingival fibroblasts to cyclical strain (up to 72 hours) using the Flexercell system and showed that CCN2 mRNA and protein was induced by strain. Strain caused the rapid activation of latent TGFβ, in a fashion that was reduced by blebbistatin and FAK/src inhibition, and the induction of endothelin (ET-1) mRNA and protein expression. Strain did not cause induction of α-smooth muscle actin or collagen type I mRNAs (proteins promoting scarring); but induced a cohort of pro-proliferative mRNAs and cell proliferation. Compared to dermal fibroblasts, gingival fibroblasts showed reduced ability to respond to TGFβ by inducing fibrogenic mRNAs; addition of ET-1 rescued this phenotype. Pharmacological inhibition of the TGFβ type I (ALK5) receptor, the endothelin A/B receptors and FAK/src significantly reduced the induction of CCN2 and pro-proliferative mRNAs and cell proliferation. Controlling TGFβ, ET-1 and FAK/src activity may be useful in controlling responses to mechanical strain in the gingiva and may be of value in controlling fibroproliferative conditions such as gingival hyperplasia; controlling ET-1 may be of benefit in controlling scarring in response to injury in the skin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Proliferation / drug effects
  • Cluster Analysis
  • Connective Tissue Growth Factor / genetics*
  • Connective Tissue Growth Factor / metabolism
  • Cyclin-Dependent Kinase 6 / genetics
  • Cyclin-Dependent Kinase 6 / metabolism
  • Endothelin-1 / metabolism
  • Fibroblasts / cytology*
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism*
  • Gene Expression Regulation / drug effects
  • Gingiva / cytology*
  • Humans
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phenotype
  • Protein Serine-Threonine Kinases / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptors, Endothelin / metabolism
  • Receptors, Transforming Growth Factor beta / metabolism
  • Signal Transduction / drug effects
  • Stress, Mechanical*
  • Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta / pharmacology

Substances

  • CDC6 protein, human
  • Cell Cycle Proteins
  • Endothelin-1
  • Nuclear Proteins
  • RNA, Messenger
  • Receptors, Endothelin
  • Receptors, Transforming Growth Factor beta
  • Transforming Growth Factor beta
  • Connective Tissue Growth Factor
  • Protein Serine-Threonine Kinases
  • CDK6 protein, human
  • Cyclin-Dependent Kinase 6
  • Receptor, Transforming Growth Factor-beta Type I
  • TGFBR1 protein, human