title: pPKC α regulates through integrin β 1 human gingival fibroblasts/Streptococcus mitis adhesion in response to HEMA.
abstract: OBJECTIVE
  To investigate in coculture of human gingival fibroblasts (HGFs) and Streptococcus mitis, the molecular mechanisms driving the response to 2-hydroxyethyl methacrylate (HEMA) in terms of eukaryotic/prokaryotic cell adhesion, signal transduction and apoptosis.
  
  
  METHODS
  The clinical strain S. mitis DS12, cultured in Trypticase soy broth was added to HGFs, obtained from fragments of healthy marginal gingival tissue and cultured in DMEM, treated with 3 mmol L(-1) 2-hydroxyethyl methacrylate (HEMA) for 48 h and processed for microscopic, western blotting and flow cytometric analyses.
  
  
  RESULTS
  2-hydroxyethyl methacrylate (HEMA) treatment increased the adhesion between S. mitis and HGFs, which seemed to be mediated by the PKC α/integrin β 1 signalling system, improved by the presence of saliva. It also reduced the viability and the adhesion of HGFs to polypropylene substrate in terms of procollagen I and MMP3 expression. The presence of saliva and S. mitis reduced the number of necrotic HGFs and upregulated the expression of both procollagen I and MMP3.
  
  
  CONCLUSIONS
  These results shed more light on the biological and molecular events occurring in vitro in a coculture model that mimics the environment of the oral cavity with HEMA treatment. The key role played by oral bacteria and saliva in preventing inflammatory and toxic processes that occur in vivo in human gingival fibroblasts upon the release of dental material monomers is confirmed.
authors.affiliation: Dipartimento di Farmacia, Università G. d'Annunzio, Chieti-Pescara, Italy.
authors.forename: V
authors.initials: V
authors.lastname: di Giacomo
authors.forename: S
authors.initials: S
authors.lastname: Pacella
authors.forename: M
authors.initials: M
authors.lastname: Rapino
authors.forename: M
authors.initials: M
authors.lastname: Di Giulio
authors.forename: S
authors.initials: S
authors.lastname: Zara
authors.forename: G
authors.initials: G
authors.lastname: Pasquantonio
authors.forename: L
authors.initials: L
authors.lastname: Cellini
authors.forename: A
authors.initials: A
authors.lastname: Cataldi
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects*; D018920:Coculture Techniques; D005881:Gingiva / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism / Q000382:microbiology; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D008689:Methacrylates / Q000494:pharmacology*; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D034361:Streptococcus mitis / Q000502:physiology*
chemical_list: D019012:Integrin beta1; D008689:Methacrylates; C005044:hydroxyethyl methacrylate; D051571:Protein Kinase C-alpha
keywords: HEMA; Streptococcus mitis; cell adhesion; coculture; integrin β 1; pPKC α