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Modulation of interleukin-8 activity by gingipains from Porphyromonas gingivalis: implications for pathogenicity of
J Mikolajczyk-Pawlinska1, J Travis, J Potempa
1Department of Microbiology and Immunology, Institute of Molecular Biology, Jagiellonian University, Krakow, Poland.
Abstract:
Gingipains are the major cysteine proteinases synthesized by Porphyromonas gingivalis which, in soluble form, are able to initially convert IL-8 (77 amino acid residues) to a more potent species truncated at the amino terminus, followed by slow degradation and destruction of chemokine biological activity. In contrast, the same enzymes when associated with bacterial outer-membrane blebs (vesicles), instantly degrade this chemokine. This division of enhancing and inactivating activity between soluble and membrane-bound gingipains can cause the compartmentalization of pro- and anti-inflammatory reactions to distal and proximal positions from bacterial plaque, respectively, which may explain why, despite the massive neutrophil accumulation at periodontitis sites, there is no elimination of infection.
Insights
Porphyromonas gingivalis gingipains exhibit dual activity: soluble forms enhance IL-8, while membrane-bound forms degrade it. This differential action may explain persistent periodontitis infections despite neutrophil presence.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Porphyromonas gingivalis is a key pathogen in periodontitis.
- Gingipains are virulence factors produced by P. gingivalis.
- Interleukin-8 (IL-8) is a critical chemokine in neutrophil recruitment.
Purpose of the Study:
- To investigate the differential activities of soluble and membrane-bound gingipains on IL-8.
- To elucidate the role of gingipain activity in the pathogenesis of periodontitis.
Main Methods:
- Enzymatic assays using purified gingipains and recombinant IL-8.
- Analysis of IL-8 processing by soluble and membrane-associated gingipains.
- Comparison of IL-8 degradation by gingipains from outer-membrane blebs.
Main Results:
- Soluble gingipains initially convert IL-8 to a more potent form.
- Membrane-bound gingipains associated with outer-membrane blebs instantly degrade IL-8.
- Differential activity leads to compartmentalized inflammatory responses.
Conclusions:
- Gingipain activity on IL-8 is dependent on its localization (soluble vs. membrane-bound).
- This compartmentalization may contribute to the failure to eliminate P. gingivalis infection in periodontitis.
- Understanding these mechanisms could inform novel therapeutic strategies.