title: Porphyromonas gingivalis lipopolysaccharide lipid A heterogeneity differentially modulates the expression of IL-6 and IL-8 in human gingival fibroblasts.
abstract: OBJECTIVE
  Porphyromonas gingivalis lipopolysaccharide (LPS) displays a significant amount of structural heterogeneity, containing both tetra- (LPS(1435/1449) ) and penta-acylated (LPS(1690) ) lipid A structures. This study investigated the effects of the two isoforms of P. gingivalis LPS on the expression of IL-6, IL-8 and TNF-α in human gingival fibroblasts (HGFs).
  
  
  METHODS
  HGFs were stimulated with P. gingivalis LPS(1435/1449) and LPS(1690) in both dose- (1 ng-10 μg/ml) and time-dependent (2-48 h) experiments. Total RNA and protein were extracted and used for analysis of the IL-6, IL-8 and TNF-α transcripts as well as IL-6 and IL-8 proteins, by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.
  
  
  RESULTS
  P. gingivalis LPS(1690) significantly up-regulated the mRNA and protein expression of IL-6 and IL-8, whereas P. gingivalis LPS(1435/1449) did not induce significant host response. The expression levels of IL-6 and IL-8 up-regulated by P. gingivalis LPS(1690) continuously increased with time course. In contrast, TNF-α transcript expression was up-regulated promptly by P. gingivalis LPS(1690) after 2 h of stimulation and gradually declined afterwards.
  
  
  CONCLUSIONS
  This study suggests that P. gingivalis LPS heterogeneity may differentially modulate the pro-inflammatory cytokine expression in HGFs, which may contribute to periodontal pathogenesis.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Thanuja D K
authors.initials: TD
authors.lastname: Herath
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Chaminda J
authors.initials: CJ
authors.lastname: Seneviratne
authors.forename: Qian
authors.initials: Q
authors.lastname: Lu
authors.forename: Richard P
authors.initials: RP
authors.lastname: Darveau
authors.forename: Cun-Yu
authors.initials: CY
authors.lastname: Wang
authors.forename: Lijian
authors.initials: L
authors.lastname: Jin
mesh_terms: D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000276:immunology; D005347:Fibroblasts / Q000276:immunology*; D005881:Gingiva / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D007155:Immunologic Factors / Q000276:immunology*; D018836:Inflammation Mediators / Q000276:immunology; D015850:Interleukin-6 / Q000276:immunology*; D016209:Interleukin-8 / Q000276:immunology*; D008050:Lipid A / Q000737:chemistry / Q000276:immunology*; D016966:Porphyromonas gingivalis / Q000276:immunology*; D011506:Proteins / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D015854:Up-Regulation
chemical_list: C508600:IL6 protein, human; D007155:Immunologic Factors; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D008050:Lipid A; D011506:Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha