title: Black tea theaflavins attenuate Porphyromonas gingivalis virulence properties, modulate gingival keratinocyte tight junction integrity and exert anti-inflammatory activity.
abstract: OBJECTIVE
  Over the last 10 years, bioactive plant food compounds have received considerable attention in regard to their beneficial effects against periodontal disease. In this study, we investigated the effects of black tea theaflavins (TFs) on the virulence properties of Porphyromonas gingivalis and gingival keratinocyte tight junction integrity. In addition, the effects of black tea TFs on the nuclear factor-κB (NF-κB) signaling pathway and proinflammatory cytokine/matrix metalloproteinase (MMP) secretion by monocytes/macrophages were assessed.
  
  
  METHODS
  Virulence factor gene expression in P. gingivalis was investigated by quantitative real-time PCR. A fluorescence assay was used to determine P. gingivalis adherence to, and invasion of, a gingival keratinocyte monolayer. Tight junction integrity of gingival keratinocytes was assessed by determination of transepithelial electrical resistance. Proinflammatory cytokine and MMP secretion by P. gingivalis-stimulated macrophages was quantified by ELISA. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to monitor NF-κB activation. Gelatin degradation was monitored using a fluorogenic assay.
  
  
  RESULTS
  Black tea TFs dose-dependently inhibited the expression of genes encoding the major virulence factors of P. gingivalis and attenuated its adherence to gingival keratinocytes. A treatment of gingival keratinocytes with black tea TFs significantly enhanced tight junction integrity and prevented P. gingivalis-mediated tight junction damage as well as bacterial invasion. Black tea TFs reduced the secretion of interleukin (IL)-1β, tumor necrosis factor-α, IL-6, chemokine (C-X-C) ligand 8, MMP-3, MMP-8 and MMP-9 by P. gingivalis-stimulated macrophages and attenuated the P. gingivalis-mediated activation of the NF-κB signaling pathway. Lastly, black tea TFs inhibited gelatin degradation by MMP-9.
  
  
  CONCLUSIONS
  This study provides clear evidence that black tea TFs represent promising multifunctional therapeutic agents for prevention and treatment of periodontal disease.
authors.affiliation: Oral Ecology Research Group, Faculty of Dentistry, Laval University, Quebec City, QC, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Ben Lagha
authors.affiliation: Oral Ecology Research Group, Faculty of Dentistry, Laval University, Quebec City, QC, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Grenier
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D044946:Biflavonoids / Q000494:pharmacology*; D002392:Catechin / Q000494:pharmacology*; D002460:Cell Line; D005881:Gingiva / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000472:pathogenicity; D060888:Real-Time Polymerase Chain Reaction; D013662:Tea / Q000737:chemistry; D019108:Tight Junctions / Q000187:drug effects*; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D044946:Biflavonoids; D013662:Tea; D037521:Virulence Factors; C056068:theaflavin; D002392:Catechin
keywords: 
  Porphyromonas gingivalis
  ; cytokine; keratinocyte; matrix metalloproteinase; periodontal disease; theaflavin; tight junction