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- Wichert, R., et al.
(author)
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Mucus Detachment by Host Metalloprotease Meprin beta Requires Shedding of Its Inactive Pro-form, which Is Abrogated by the Pathogenic Protease RgpB
- 2017
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In: Cell Reports. - : Elsevier BV. - 2211-1247. ; 21:8, s. 2090-2103
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Journal article (peer-reviewed)abstract
- The host metalloprotease meprin beta is required for mucin 2 (MUC2) cleavage, which drives intestinal mucus detachment and prevents bacterial over-growth. To gain access to the cleavage site in MUC2, meprin b must be proteolytically shed from epithelial cells. Hence, regulation of meprin b shedding and activation is important for physiological and pathophysiological conditions. Here, we demonstrate that meprin b activation and shedding are mutually exclusive events. Employing ex vivo small intestinal organoid and cell culture experiments, we found that ADAM-mediated shedding is restricted to the inactive pro-form of meprin beta and is completely inhibited upon its conversion to the active form at the cell surface. This strict regulation of meprin beta activity can be overridden by pathogens, as demonstrated for the bacterial protease Arg-gingipain (RgpB). This secreted cysteine protease potently converts membrane-bound meprin beta into its active form, impairing meprin beta shedding and its function as a mucus-detaching protease.
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- De Vries, C, et al.
(author)
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ANTIBODIES TO PORPHYROMONAS GINGIVALIS ASSOCIATE WITH THE PRESENCE OF RHEUMATOID ARTHRITIS-RELATED AUTOANTIBODIES IN PATIENTS WITH PERIODONTITIS
- 2021
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In: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 80, s. 996-996
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Conference paper (other academic/artistic)abstract
- Epidemiologic studies have demonstrated a link between periodontitis (PD) and rheumatoid arthritis (RA), specifically RA characterized by anti-citrullinated protein antibodies (ACPA). The keystone pathogen driving PD, Porphyromonas gingivalis (Pg), is the only pathogen known to express peptidylarginine deiminase (PAD), a citrullinating enzyme. Hence, Pg has been proposed to be involved in triggering the ACPA response, by generating citrullinated antigens in an inflammatory milieu(1). Another major virulence factor of Pg is arginine gingipain B (RgpB), a proteinase which cleaves proteins so that P.PAD can access the site where citrullination takes place. We have previously shown elevated anti-RgpB IgG levels in ACPA+ RA patients, even before clinical onset(2, 3), and we hypothesize that anti-RgpB IgG could serve as a serological marker to identify PD patients with increased risk of developing ACPA+ RA.Objectives:Based on this hypothesis, we set out to investigate whether anti-RgpB IgG was associated with PD, PD severity, autoimmunity in general, and the ACPA response in particular.Methods:Anti-RgpB IgG, as well as RA- and systemic lupus erythematosus (SLE)-related autoantibodies targeting cyclic citrullinated peptide(s) (CCP2), rheumatoid factor (RF), dsDNA, cardiolipin, and β2 glycoprotein, were measured by ELISA in serum samples from the ParoKrank study, which is a well-characterized cohort of 805 patients with a first myocardial infarction and 805 matched controls, where periodontal status has been determined by dentists(4). In this study, individuals with PD (n=941) were compared to individuals without PD (n=557).Results:We detected significantly elevated (p<0,0001) anti-RgpB IgG levels in PD compared to non-PD individuals, with highest levels recorded in severe PD. Anti-RgpB IgG levels were significantly increased in PD patients positive for CCP2 and/or RF (n=50), when compared to PD patients negative for CCP2 and RF (n=507), p<0,05, and when compared to non-PD individuals positive for CCP2 and/or RF (n=62), p < 0,05. Notably, these differences were not seen for SLE-related autoantibodies. In addition, anti-RgpB IgG levels were significantly elevated amongst MI patients versus controls (p < 0,05), supporting the previous finding that PD is more common among MI patients(4).Conclusion:Our data demonstrates a specific association between severe PD, elevated anti-RgpB IgG levels and RA-related autoantibodies, supporting a role for Pg in linking PD to ACPA+ RA. Further investigation will be needed to confirm whether anti-RgpB IgG can be used as a serological marker to identify PD patients with increased risk of developing ACPA+ RA.References:[1]Rosenstein ED, Greenwald RA, Kushner LJ, Weissmann G. Hypothesis: the humoral immune response to oral bacteria provides a stimulus for the development of rheumatoid arthritis. Inflammation. 2004;28(6):311-8.[2]Kharlamova N, Jiang X, Sherina N, Potempa B, Israelsson L, Quirke AM, et al. Antibodies to Porphyromonas gingivalis Indicate Interaction Between Oral Infection, Smoking, and Risk Genes in Rheumatoid Arthritis Etiology. Arthritis Rheumatol. 2016;68(3):604-13.[3]Johansson L, Sherina N, Kharlamova N, Potempa B, Larsson B, Israelsson L, et al. Concentration of antibodies against Porphyromonas gingivalis is increased before the onset of symptoms of rheumatoid arthritis. Arthritis Res Ther. 2016;18(1):201.[4]Rydén L, Buhlin K, Ekstrand E, Faire Ud, Gustafsson A, Holmer J, et al. Periodontitis Increases the Risk of a First Myocardial Infarction. Circulation. 2016;133(6):576-83.Disclosure of Interests:None declared
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| 7. |
- van der Post, Sjoerd, 1981, et al.
(author)
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Site-specific O-glycosylation on the MUC2 mucin protein inhibits cleavage by the Porphyromonas gingivalis secreted cysteine protease (RgpB).
- 2013
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In: The Journal of biological chemistry. - 1083-351X. ; 288:20, s. 14636-46
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Journal article (peer-reviewed)abstract
- The colonic epithelial surface is protected by an inner mucus layer that the commensal microflora cannot penetrate. We previously demonstrated that Entamoeba histolytica secretes a protease capable of dissolving this layer that is required for parasite penetration. Here, we asked whether there are bacteria that can secrete similar proteases. We screened bacterial culture supernatants for such activity using recombinant fragments of the MUC2 mucin, the major structural component, and the only gel-forming mucin in the colonic mucus. MUC2 has two central heavily O-glycosylated mucin domains that are protease-resistant and has cysteine-rich N and C termini responsible for polymerization. Culture supernatants of Porphyromonas gingivalis, a bacterium that secretes proteases responsible for periodontitis, cleaved the MUC2 C-terminal region, whereas the N-terminal region was unaffected. The active enzyme was isolated and identified as Arg-gingipain B (RgpB). Two cleavage sites were localized to IR↓TT and NR↓QA. IR↓TT cleavage will disrupt the MUC2 polymers. Because this site has two potential O-glycosylation sites, we tested whether recombinant GalNAc-transferases (GalNAc-Ts) could glycosylate a synthetic peptide covering the IRTT sequence. Only GalNAc-T3 was able to glycosylate the second Thr in IRTT, rendering the sequence resistant to cleavage by RgpB. Furthermore, when GalNAc-T3 was expressed in CHO cells expressing the MUC2 C terminus, the second threonine was glycosylated, and the protein became resistant to RgpB cleavage. These findings suggest that bacteria can produce proteases capable of dissolving the inner protective mucus layer by specific cleavages in the MUC2 mucin and that this cleavage can be modulated by site-specific O-glycosylation.
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| 8. |
- Staniec, Dominika, et al.
(author)
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Calcium Regulates the Activity and Structural Stability of Tpr, a Bacterial Calpain-like Peptidase.
- 2015
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In: Journal of Biological Chemistry. - 1083-351X. ; 290:45, s. 27248-27260
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Journal article (peer-reviewed)abstract
- Porphyromonas gingivalis is a peptide-fermenting asaccharolytic periodontal pathogen. Its genome contains several genes encoding cysteine peptidases other than gingipains. One of these genes (PG1055) encodes a protein called Tpr (thiol protease), which has sequence similarity to cysteine peptidases of the papain and calpain families. In this study, we biochemically characterize Tpr. We found that the 55 kDa Tpr inactive zymogen proteolytically processes itself into active forms of 48 kDa, 37 kDa, and 33 kDa via sequential truncations at the N-terminus. These processed molecular forms of Tpr are associated with the bacterial outer membrane, where they are likely responsible for the generation of metabolic peptides required for survival of the pathogen. Both autoprocessing and activity were dependent on calcium concentrations greater than 1 mM, consistent with the protein's activity within the intestinal and inflammatory milieus. Calcium also stabilized the Tpr structure and rendered the protein fully resistant to proteolytic degradation by gingipains. Together, our findings suggest that Tpr is an example of a bacterial calpain, a calcium-responsive peptidase that may generate substrates required for the peptide-fermenting metabolism of P. gingivalis. Aside from nutrient generation, Tpr may also be involved in evasion of host immune response through degradation of the antimicrobial peptide LL-37 and complement proteins C3, C4 and C5. Taken together, these results indicate that Tpr likely represents an important pathogenesis factor for P. gingivalis.
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| 9. |
- Zdzalik, M., et al.
(author)
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Prevalence of genes encoding extracellular proteases in Staphylococcus aureus - important targets triggering immune response in vivo
- 2012
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In: Fems Immunology and Medical Microbiology. - 0928-8244. ; 66:2, s. 220-229
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Journal article (peer-reviewed)abstract
- Proteases of Staphylococcus aureus have long been considered to function as important virulence factors, although direct evidence of the role of particular enzymes remains incomplete and elusive. Here, we sought to provide a collective view of the prevalence of extracellular protease genes in genomes of commensal and pathogenic strains of S.aureus and their expression in the course of human and mouse infection. Data on V8 protease, staphopains A and B, aureolysin, and the recently described and poorly characterized group of six Spl proteases are provided. A phylogenetically diverse collection of 167 clinical isolates was analyzed, resulting in the comprehensive genetic survey of the prevalence of protease-encoding genes. No correlation between identified gene patterns with specific infections was established. Humoral response against the proteases of interest was examined in the sera derived from human patients and from a model mouse infection. The analysis suggests that at least some, if not all, tested proteases are expressed and secreted during the course of infection. Overall, the results presented in this study support the hypothesis that the secretory proteases as a group may contribute to the virulence of S.aureus.
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