Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1186/s12903-025-05584-4

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Other Link： https://link.springer.com/article/10.1186/s12903-025-05584-4/fulltext.html

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

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Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Porphyromonas gingivalis is commonly known as one of the major pathogens contributing to periodontitis, and its persistent infection may increase the risk for the disease. The proinflammatory mediators, including IL-6, TNF-α, and cyclooxygenase-2 (COX-2)/PGE2, are closely associated with progression of periodontitis. In this study, we focused on the cysteine protease “gingipains,” lysine-specific gingipain, arginine-specific gingipain (Rgp) A, and RgpB, produced by P. gingivalis, and used the wild-type strain and several gene-deletion mutants (rgpA, rgpB, kgp, and fimA) to elucidate the involvement of gingipains in COX-2 expression and PGE2 production. We infected human monocytes, which are THP-1 cells and primary monocytes, with these bacterial strains and found that gingipains were involved in induction of COX-2 expression and PGE2 production. We have shown that the protease activity of gingipains was crucial for these events by using gingipain inhibitors. Furthermore, activation of ERK1/2 and IκB kinase was required for gingipain-induced COX-2 expression/PGE2 production, and these kinases activated two transcription factors, c-Jun/c-Fos (AP-1) and NF-κB p65, respectively. In particular, these data suggest that gingipain-induced c-Fos expression via ERK is essential for AP-1 formation with c-Jun, and activation of AP-1 and NF-κB p65 plays a central role in COX-2 expression/PGE2 production. Thus, we show the (to our knowledge) novel finding that gingipains with the protease activity from P. gingivalis induce COX-2 expression and PGE2 production via activation of MEK/ERK/AP-1 and IκB kinase/NF-κB p65 in human monocytes. Hence it is likely that gingipains closely contribute to the inflammation of periodontal tissues.

DOI： 10.4049/jimmunol.2100866

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.job.2020.09.007

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

The periodontal pathogen Porphyromonas gingivalis shows colonial pigmentation on blood agar and produces gingipains (Kgp, RgpA, and RgpB), cysteine proteases involved in an organism's virulence and pigmentation. We showed previously that deletion of the PGN_0300 gene abolished the pigmentation activity and reduced the proteolytic activity of gingipains. The role of the PGN_0297 gene, which consists of an operon with the PGN_0300 gene, is unclear. Herein we examined the effect of PGN_0297 gene deletion on the pigmentation and proteolytic activities and transcriptional levels of gingipains. A PGN_0297 gene deletion mutant (ΔPGN_0297) did not exhibit the pigmentation. The proteolytic activity of the gingipains was decreased in the culture supernatant and on the cell surface of ΔPGN_0297. The mutant ΔPGN_0297 failed to attenuate Akt phosphorylation at Thr308 and Ser473, but both phosphorylations were attenuated in the wild-type and its complementation strain. The deletion of PGN_0297 gene did not substantially affect the transcriptional levels of the gingipain genes kgp, rgpA, and rgpB. Taken together, these results indicate that PGN_0297 is closely involved in the secretion and maturation of gingipains.

DOI： 10.18926/AMO/56933

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