Roles of Porphyromonas gulae proteases in bacterial and host cell biology

Alam Saki Urmi, Hiroaki Inaba, Ryota Nomura, Sho Yoshida, Naoya Ohara, Fumitoshi Asai, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Porphyromonas gulae, an animal-derived periodontal pathogen, expresses several virulence factors, including fimbria, lipopolysaccharide (LPS) and proteases. We previously reported that its invasive efficiency was dependent on fimbriae types. In addition, P. gulae LPS increased inflammatory responses via toll-like receptors. The present study was conducted to investigate the involvement of P. gulae proteases in bacterial and host cell biology. Porphyromonas gulae strains showed an ability to agglutinate mouse erythrocytes and also demonstrated co-aggregation with Actinomyces viscosus, while the protease inhibitors antipain, PMSF, TLCK and leupeptin diminished P. gulae proteolytic activity, resulting in inhibition of haemagglutination and co-aggregation with A. viscosus. In addition, specific proteinase inhibitors were found to reduce bacterial cell growth. Porphyromonas gulae inhibited Ca9-22 cell proliferation in a multiplicity of infection- and time-dependent manner. Additionally, P. gulae-induced decreases in cell contact and adhesion-related proteins were accompanied by a marked change in cell morphology from well spread to rounded. In contrast, inhibition of protease activity prevented degradation of proteins, such as E-cadherin, β-catenin and focal adhesion kinase, and also blocked inhibition of cell proliferation. Together, these results indicate suppression of the amount of human proteins, such as γ-globulin, fibrinogen and fibronectin, by P. gulae proteases, suggesting that a novel protease complex contributes to bacterial virulence.

Original languageEnglish
Article numbere13312
JournalCellular Microbiology
Issue number8
Publication statusPublished - Aug 2021


  • P. gulae
  • coaggregation
  • haemagglutination
  • protease
  • protein degradation

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Virology


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