title: Entry of Porphyromonas gingivalis outer membrane vesicles into epithelial cells causes cellular functional impairment.
abstract: Porphyromonas gingivalis, a periodontal pathogen, secretes outer membrane vesicles (MVs) that contain major virulence factors, including proteases termed gingipains (Arg-gingipain [Rgp] and Lys-gingipain [Kgp]). We recently showed that P. gingivalis MVs swiftly enter host epithelial cells via an endocytosis pathway and are finally sorted to lytic compartments. However, it remains unknown whether MV entry impairs cellular function. Herein, we analyzed cellular functional impairment following entry of P. gingivalis into epithelial cells, including HeLa and immortalized human gingival epithelial (IHGE) cells. After being taken up by endocytic vacuoles, MVs degraded the cellular transferrin receptor (TfR) and integrin-related signaling molecules, such as paxillin and focal adhesion kinase (FAK), which resulted in depletion of intracellular transferrin and inhibition of cellular migration. Few Rgp-null MVs entered the cells, and these negligibly degraded TfR, whereas paxillin and FAK degradation was significant. In contrast, Kgp-null MVs clearly entered the cells and degraded TfR, while they scarcely degraded paxillin and FAK. In addition, both wild-type and Kgp-null MVs significantly impaired cellular migration, whereas the effect of Rgp-null MVs was limited. Our findings suggest that, following entry of P. gingivalis MVs into host cells, MV-associated gingipains degrade cellular functional molecules such as TfR and paxillin/FAK, resulting in cellular impairment, indicating that P. gingivalis MVs are potent vehicles for transmission of virulence factors into host cells and are involved in the etiology of periodontitis.
authors.affiliation: Department of Oral Frontier Biology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita-Osaka 565-0871, Japan.
authors.forename: Nobumichi
authors.initials: N
authors.lastname: Furuta
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Atsuo
authors.initials: A
authors.lastname: Amano
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology*; D000080867:Gingipain Cysteine Endopeptidases; D006367:HeLa Cells; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D051419:Paxillin / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000378:metabolism / Q000472:pathogenicity*; D011990:Receptors, Transferrin / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000382:microbiology; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D051419:Paxillin; D011990:Receptors, Transferrin; D037521:Virulence Factors; D003546:Cysteine Endopeptidases