Effect of Inactivation of the Arg- and/or Lys-Gingipain Gene on Selected Virulence and Physiological Properties of
            <i>Porphyromonas gingivalis</i>

Grenier, Daniel; Roy, Sophie; Chandad, Fatiha; Plamondon, Pascale; Yoshioka, Masami; Nakayama, Koji; Mayrand, D.

doi:10.1128/iai.71.8.4742-4748.2003

Cited by 77 publications

(78 citation statements)

References 44 publications

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“…The authors suggest that lysis is prevented by the presence of anionic polysaccharides on a bacterial surface. The results of this study are in contrast with other published results that showed that a P. gingivalis mutant lacking all three gingipains was extremely sensitive to lysis by complement (30). In direct contrast, a mutant lacking HRgpA and RgpB was reported to survive in NHS equally well as the wild type (20) or to survive at 28% as compared with 87% for the wild type (30).…”

Section: Discussioncontrasting

confidence: 99%

Biphasic Effect of Gingipains from Porphyromonas gingivalis on the Human Complement System

Popadiak

Potempa

Riesbeck

et al. 2007

The Journal of Immunology

158

214

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Periodontitis is an inflammatory disease of the supporting structures of the teeth and is caused by, among other agents, Porphyromonas gingivalis. P. gingivalis is very resistant to killing by human complement, which is present in a gingival fluid at 70% of the serum concentration. We found that the incubation of human serum with purified cysteine proteases of P. gingivalis (gingipains) or P. gingivalis wild-type strains W83 and W50 resulted in a drastic decrease of the bactericidal activity of the serum. In contrast, serum treated with P. gingivalis mutants lacking gingipains (particularly strains without HRgpA) maintained significant bactericidal activity. To understand in detail the mechanism by which gingipains destroy the serum bactericidal activity, we investigated the effects of gingipains on the human complement system. We found that all three proteases degraded multiple complement components, with arginine-specific gingipains (HRgpA and RgpB) being more efficient than lysine-specific gingipain (Kgp). Interestingly, all three proteases at certain concentrations were able to activate the C1 complex in serum, which resulted in the deposition of C1q on inert surfaces and on bacteria themselves. It is therefore plausible that P. gingivalis activates complement when present at low numbers, resulting in a local inflammatory reaction and providing the bacteria with a colonization opportunity and nutrients. At later stages of infection the concentration of proteases is high enough to destroy complement factors and thus render the bacteria resistant to the bactericidal activity of complement.

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Section: Discussioncontrasting

confidence: 99%

Biphasic Effect of Gingipains from Porphyromonas gingivalis on the Human Complement System

Popadiak

Potempa

Riesbeck

et al. 2007

The Journal of Immunology

158

214

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“…Proteases and fimbriae produced by P. gingivalis cause inflammation in mammalian models (15,(23)(24)(25). We tested the killing effects of heat-treated mutant strains of P. gingivalis that lack genes encoding these virulence factors.…”

Section: Resultsmentioning

confidence: 99%

Porphyromonas gingivalis Peptidoglycans Induce Excessive Activation of the Innate Immune System in Silkworm Larvae*

Ishii

Hamamoto

Imamura

et al. 2010

Journal of Biological Chemistry

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Porphyromonas gingivalis, a pathogen that causes inflammation in human periodontal tissue, killed silkworm (Bombyx mori, Lepidoptera) larvae when injected into the blood (hemolymph). Silkworm lethality was not rescued by antibiotic treatment, and heat-killed bacteria were also lethal. Heat-killed bacteria of mutant P. gingivalis strains lacking virulence factors also killed silkworms. Silkworms died after injection of peptidoglycans purified from P. gingivalis (pPG), and pPG toxicity was blocked by treatment with mutanolysin, a peptidoglycan-degrading enzyme. pPG induced silkworm hemolymph melanization at the same dose as that required to kill the animal. pPG injection increased caspase activity in silkworm tissues. pPGinduced silkworm death was delayed by injecting melanizationinhibiting reagents (a serine protease inhibitor and 1-phenyl-2-thiourea), antioxidants (N-acetyl-L-cysteine, glutathione, and catalase), and a caspase inhibitor (Ac-DEVD-CHO). Thus, pPG induces excessive activation of the innate immune response, which leads to the generation of reactive oxygen species and apoptotic cell death in the host tissue.The immune system is crucial for animal self-defense against pathogenic microorganisms. On the other hand, excessive activation of immune responses may cause serious damage to the host. Severely infected human patients die of septic shock and multiple organ failure, which seem to be caused by excessive activation of the host immune systems by the pathogens. The underlying pathologic mechanisms of sepsis, however, are not clear, and effective antiseptic remedies are yet to be established.In vertebrates, the immune system is divided into two categories: innate immunity and acquired immunity. Because innate immunity is the front line of host defense against pathogens and is involved in initiating acquired immune responses, it is a prominent target in studies of the pathology of diseases caused by immune system deregulation. Most of the major components of the innate immune system are conserved from vertebrates to invertebrates (1). Thus, invertebrate models with simple biologic systems are useful for studying the activation mechanisms of innate immune responses, but there are no reports of pathologic invertebrate models that are killed by excessive innate immune responses caused by bacterial invasion of the bloodstream.The silkworm, Bombyx mori, is an invertebrate model that can be administered quantitative injections of pathogens and drugs (2-4) and is suitable for the study of innate immunity (5). We recently reported that peptidoglycans and glucans, the cell wall components of bacteria and fungi, respectively, trigger the generation of reactive oxygen species (ROS) 2 from silkworm blood cells (hemocytes) followed by the activation of serine proteases and induce the activation of paralytic peptide (PP), an insect cytokine (6). At the same time, peptidoglycans and glucans induce melanization, a polymerization reaction of melanin that involves serine proteases (7,8), and phenoloxidase (a copper-conta...

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“…Biofilm formation was assayed in 96-well microtiter dishes made of polystyrene (Falcon 353936) using a slightly modified previously published protocol (29). In brief, THBHK (200 l/well) was inoculated from cells patched on BAPHK agar plates containing tetracycline.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Biofilm Formation and Loss of Capsule Synthesis: Deletion of a Putative Glycosyltransferase inPorphyromonas gingivalis

Davey¹,

Duncan²

2006

J Bacteriol

111

104

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Periodontitis is a biofilm-mediated disease. Porphyromonas gingivalis is an obligate anaerobe consistently associated with severe manifestations of this disease. As an opportunistic pathogen, the ability to proliferate within and disseminate from subgingival biofilm (plaque) is central to its virulence. Here, we report the isolation of a P. gingivalis transposon insertion mutant altered in biofilm development and the reconstruction and characterization of this mutation in three different wild-type strains. The mutation responsible for the altered biofilm phenotype was in a gene with high sequence similarity (ϳ61%) to a glycosyltransferase gene. The gene is located in a region of the chromosome that includes up to 16 genes predicted to be involved in the synthesis and transport of capsular polysaccharide. The phenotype of the reconstructed mutation in all three wild-type backgrounds is that of enhanced biofilm formation. In addition, in strain W83, a strain that is encapsulated, the glycosyltransferase mutation resulted in a loss of capsule. Further experiments showed that the W83 mutant strain was more hydrophobic and exhibited increased autoaggregation. Our results indicate that we have identified a gene involved in capsularpolysaccharide synthesis in P. gingivalis and that the production of capsule prevented attachment and the initiation of in vitro biofilm formation on polystyrene microtiter plates.The clinical importance of dental plaque and its accessibility for in vivo research makes it one of most studied and bestunderstood biofilm communities. It is now well documented that gram-negative anaerobic bacteria play a significant role in the development of periodontitis, with Porphyromonas gingivalis being implicated as one of the major players in the progression of this chronic disease (10,19,30,61). A number of factors are associated with the virulence of the organism, including a variety of proteases, endotoxins, and collegenases and the production of surface structures, such as fimbriae and capsular polysaccharide (38). This opportunistic pathogen also attaches to and invades human epithelial cells (18,53,56,57), connective tissue, and endothelial cells (15,17,55), and invasion has been shown to be mediated by the expression of fimbriae and a variety of surface adhesins. It is evident that the growth of P. gingivalis within the subgingival plaque is central to the disease process; however, although there have been numerous studies of the pathogenicity of the organism and its interactions with other organisms within the biofilm community, little is known about the molecular-genetic basis of biofilm formation in P. gingivalis.Research on oral biofilms has focused on determining the spatial organization and complex development of plaque by examining the succession of organisms in the growing biofilm. By monitoring the development of the microbial community on the tooth surface after professional cleaning, studies have demonstrated that the early colonizers are primarily grampositive organisms and the late, o...

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Effect of Inactivation of the Arg- and/or Lys-Gingipain Gene on Selected Virulence and Physiological Properties of Porphyromonas gingivalis

Cited by 77 publications

References 44 publications

Biphasic Effect of Gingipains from Porphyromonas gingivalis on the Human Complement System

Biphasic Effect of Gingipains from Porphyromonas gingivalis on the Human Complement System

Porphyromonas gingivalis Peptidoglycans Induce Excessive Activation of the Innate Immune System in Silkworm Larvae*

Enhanced Biofilm Formation and Loss of Capsule Synthesis: Deletion of a Putative Glycosyltransferase inPorphyromonas gingivalis

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