Virulence of Porphyromonas gingivalis is altered by substitution of fimbria gene with different genotype

Abstract

SummaryPorphyromonas gingivalis is a periodontal pathogen whose fimbriae are classified into six genotypes based on the diversity of the fimA genes encoding each fimbria subunit. It was suggested that P. gingivalis strains with type II fimbriae were more virulent than type I strains. For the present study, we generated the mutants in which fimA was substituted with different genotypes to study virulence of type II fimbriae. Using plasmid vectors, fimA of ATCC33277 (type I strain) was substituted with type II fimA, and that of OMZ314 (type II strain) with type I fimA. The substitution of type I fimA with type II enhanced bacterial adhesion/invasion to epithelial cells, whereas substitution with type I fimA resulted in diminished efficiency. Following bacterial invasion, type II clones swiftly degraded cellular paxillin and focal adhesion kinase, and inhibited cellular migration, whereas type I clones and DfimA mutants did not. BIAcore analysis demonstrated that type II fimbriae possess greater adhesive abilities for their receptor a5b1-integrin than those of type I. In a mouse abscess model, the type II clones significantly induced serum IL-1b and IL-6, as well as other infectious symptoms. These results suggest that type II fimbriae are a critical determinant of P. gingivalis virulence.

Association of the invasion ability ofPorphyromonas gingivaliswith the severity of periodontitis

“…Because fimA-disrupted mutants have been shown to lose almost all of their invasive ability, 26 we analyzed the entire coding sequence of the fimA gene to determine an underlying mechanism for the heterogenic invasive ability of P. gingivalis. A sequence similarity search revealed that KUMC-P10 has a type I genotype, while all the other strains have type II.…”

Identification of Hop Polyphenolic Components Which Inhibit Prostaglandin E2 Production by Gingival Epithelial Cells Stimulated with Periodontal Pathogen

“…Cell Culture Immortalized HGE cells 15) were kindly provided by Professor Murakami (Osaka University Graduate School of Dentistry). HGE cells were grown in Humedia KB-2 (Kurabo, Osaka, Japan) at 37°C with 5% CO 2 as described previously, 15) and 24 h before stimulation of P. gingivalis vesicles, the cells were moved to Dulbecco's modified Eagle's medium (Sigma, St. Louis, MO, U.S.A.) with 10% fetal calf serum (Invitrogen Co., Carlsbad, CA, U.S.A.).…”

Genetic exchange and reassignment in Porphyromonas gingivalis

“…When the type I allele was replaced with the type III or IV allele, increased invasion of gingival fibroblasts were seen compared to that achieved with the isogenic parent strain. By using plasmid vectors, Kato et al [26] substituted fim A of ATCC 33277 with type II fim A, and that of OMZ314 (type II strain) with type I fim A. Replacement of type I fim A with type II increased bacterial adhesion/invasion to epithelial cells, whereas substitution with type I fim A resulted in reduced efficiency.…”