Periodontitis is classified as a microbiota shift disease, whereby a very rich and diverse commensal flora characteristic for good oral health becomes dominated by several Gram-negative, anaerobic bacterial species, among which, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola constitute the so called "red complex" of microorganisms frequently associated with the development and progression of the disease. The common consequence of these three bacteria and a secondary periodontopathogen, Prevotella intermedia, is their production of proteolytic enzymes. Proteases of P. gingivalis and T. denticola are known to dysregulate tissue homeostasis and/or to frustrate defensive inflammatory responses, thus, significantly contributing to pathological changes in the infected periodontium. In contrast, virtually nothing is known about proteases of T. forsythia and P. intermedia although it has been well documented that proteases from the former organism are produced in vivo and their activity correlates with periodontal destruction. Here, we postulate that novel proteases produced by T. forsythia (forsypsin) and P. intermedia (interpains) promote periodontal tissue damage by deregulation of tightly controlled host proteolytic systems. Furthermore, we suggest that the combined proteolytic activity produced locally by periodontopathogens may be a primary mechanism for synergistic periodontal tissue damage and contributes to mutual survival of the red complex bacteria. Most interestingly, we have found that forsypsin and interpains, as well as many other acknowledged virulence factors of P. gingivalis and T. forsythia share with gingipains a conserved C-terminal domain. We have shown that this domain, together with a unique periplasmic protein and a unique outer membrane translocon protein conserved in these species is essential for gingipain secretion. This implies that a novel bacterial protein export system is employed by periodontopathogens to secrete a number of confirmed and putative virulence factors. For these reasons, the specific aims of this project are as follows: 1) to use an array of biochemical and molecular biological methods to investigate the mechanism of gingipain translocation through the outer membrane of P. gingivalis and confirm the presence of this unique secretion pathway in both T. forsythia and P. intermedia;2) to characterize novel proteases from T. forsythia and P. intermedia, especially with regard to their ability to complement and/or synergize with the gingipain activity, and 3) to determine the complementary or synergistic role of proteases from P. gingivalis, T. forsythia and P. intermedia for in vivo proliferation and dissemination of bacteria in monomicrobial and mixed microbial infections using a murine chamber model.

Public Health Relevance

The results of these proposed studies should not only illuminate the synergistic role of bacterial proteases in mixed infections but also shed light on a novel pathway for the secretion of virulence factors unique to P. gingivalis, T. forsythia and P. intermedia. This insight may enable the design of antibodies or chemical compounds to block the export of multiple virulence factors from major periodontopathogens, which in the long term, may revolutionize treatment and prophylaxis of periodontal disease.

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Research Project (R01)
Project #
Application #
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Lunsford, Dwayne
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Louisville
Schools of Dentistry
United States
Zip Code
Koziel, Joanna; Chmiest, Daniela; Bryzek, Danuta et al. (2015) The Janus face of ?-toxin: a potent mediator of cytoprotection in staphylococci-infected macrophages. J Innate Immun 7:187-98
Wilensky, Asaf; Tzach-Nahman, Rinat; Potempa, Jan et al. (2015) Porphyromonas gingivalis gingipains selectively reduce CD14 expression, leading to macrophage hyporesponsiveness to bacterial infection. J Innate Immun 7:127-35
Bryzek, D; Ksiazek, M; Bielecka, E et al. (2014) A pathogenic trace of Tannerella forsythia - shedding of soluble fully active tumor necrosis factor ? from the macrophage surface by karilysin. Mol Oral Microbiol 29:294-306
Jusko, Monika; Potempa, Jan; Kantyka, Tomasz et al. (2014) Staphylococcal proteases aid in evasion of the human complement system. J Innate Immun 6:31-46
de Diego, IƱaki; Veillard, Florian; Sztukowska, Maryta N et al. (2014) Structure and mechanism of cysteine peptidase gingipain K (Kgp), a major virulence factor of Porphyromonas gingivalis in periodontitis. J Biol Chem 289:32291-302
Tomek, M B; Neumann, L; Nimeth, I et al. (2014) The S-layer proteins of Tannerella forsythia are secreted via a type IX secretion system that is decoupled from protein O-glycosylation. Mol Oral Microbiol 29:307-20
Morandini, Ana Carolina; Ramos-Junior, Erivan S; Potempa, Jan et al. (2014) Porphyromonas gingivalis fimbriae dampen P2X7-dependent interleukin-1? secretion. J Innate Immun 6:831-45
Koro, Catalin; Bielecka, Ewa; Dahl-Knudsen, Anders et al. (2014) Carbamylation of immunoglobulin abrogates activation of the classical complement pathway. Eur J Immunol 44:3403-12
Kantyka, Tomasz; Pyrc, Krzysztof; Gruca, Milosz et al. (2013) Staphylococcus aureus proteases degrade lung surfactant protein A potentially impairing innate immunity of the lung. J Innate Immun 5:251-60
Hellvard, Annelie; Maresz, Katarzyna; Schilling, Stephan et al. (2013) Glutaminyl cyclases as novel targets for the treatment of septic arthritis. J Infect Dis 207:768-77

Showing the most recent 10 out of 107 publications