Porphyromonas gingivalis fimbriae are pro-inflammatory but do not play a prominent role in the innate immune response to P. gingivalis.
The fimA gene encodes the major fimbrial protein of Porphyromonas gingivalis. It has been shown to stimulate adhesion to salivary proteins and other bacteria. It is also thought to play a major role in invading and stimulating host cells. To determine whether the fimA gene represents one of the principal molecules of P. gingivalis that induces inflammation, we tested purified FimA protein and a mutant P. gingivalis (DPG3) that lacks the fimA gene versus wild-type (WT) P. gingivalis. When injected into connective tissue of the scalp, purified FimA protein induced TNF-alpha and MIP-2 expression confirming that it is pro-inflammatory. WT P. gingivalis induced TNF-alpha expression and recruitment of PMNs in the same model. However, DPG3 P. gingivalis stimulated TNF expression and PMN recruitment to the same extent. The latter was consistent with similar induction of the chemokine MIP-2. Similar results were obtained with diabetic mice that have a more prolonged inflammatory response to bacterial stimulation. These results indicate that FimA is a potent inducer of inflammatory cytokine expression but, in the context of P. gingivalis infection, it is not a principal stimulator of the innate host response.
Graves
Dana T
DT
Department of Periodontology and Oral Biology, Boston University School of Dental Medicine, Boston, Massachusetts 02118, USA. dgraves@bu.edu
Naguib
Ghada
G
Lu
Huafei
H
Desta
Tesfahun
T
Amar
Salomon
S
D000818:Animals; D054426:Chemokine CXCL2; D018925:Chemokines / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000276:immunology; D036781:Fimbriae Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D010861:Fimbriae, Bacterial / Q000502:physiology*; D015870:Gene Expression; D005798:Genes, Bacterial; D007113:Immunity, Innate; D051379:Mice; D008815:Mice, Inbred Strains; D009154:Mutation; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000276:immunology*; D012333:RNA, Messenger / Q000378:metabolism; D012535:Scalp / Q000276:immunology / Q000382:microbiology; D012886:Skull / Q000473:pathology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D054426:Chemokine CXCL2; D018925:Chemokines; C404915:Cxcl2 protein, mouse; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D036781:Fimbriae Proteins