Characterization of the trypsin-like enzymes of Porphyromonas gingivalis W83 using a radiolabeled active-site-directed inhibitor

Curtis, Michael A.; Ramakrishnan, M.; Slaney, J. M.

doi:10.1099/00221287-139-5-949

Cited by 44 publications

(35 citation statements)

References 40 publications

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“…55,56 To show that the measure of aggregation observed (increase in the light transmittance level) was reflective of true platelet activation and is thus genuine aggregation, rather than an agglutination phenomenon, an inhibitor of platelet activation was used. Preincubation of platelets with 100 ng/mL PGI 2 or 10 M forskolin (inhibitors of platelet activation) at 37°C for 15 minutes completely inhibited the aggregation induced by 0.25 nM HRgpA and 20 nM RgpB (data not shown), verifying that HRgpA and RgpB indeed cause true platelet aggregation.…”

Section: Hrgpa and Rgpb Induce Platelet Aggregationmentioning

confidence: 99%

Activation of protease-activated receptors by gingipains fromPorphyromonas gingivalis leads to platelet aggregation: a new trait in microbial pathogenicity

Lourbakos

Yuan

Jenkins

et al. 2001

Blood

221

184

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Section: Hrgpa and Rgpb Induce Platelet Aggregationmentioning

confidence: 99%

Activation of protease-activated receptors by gingipains fromPorphyromonas gingivalis leads to platelet aggregation: a new trait in microbial pathogenicity

Lourbakos

Yuan

Jenkins

et al. 2001

Blood

221

184

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“…However, because MAb 5A1 does not block Hb binding (N. Hunter, unpublished data), there is no evidence to indicate that the epitope shared by HA2 and HA1 is involved in Hb or Hm binding. It has been proposed HA1 functions for hemagglutination (11). From these assays it is concluded that HA2-proteins are major contributors to cell surface Hb binding.…”

Section: Neutralization Of Hb Bindingmentioning

confidence: 99%

Porphyrin-Mediated Cell Surface Heme Capture from Hemoglobin byPorphyromonas gingivalis

et al. 2003

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The porphyrin requirements for growth recovery of Porphyromonas gingivalis in heme-depleted cultures are investigated. In addition to physiologically relevant sources of heme, growth recovery is stimulated by a number of noniron porphyrins. These data demonstrate that, as for Haemophilus influenzae, reliance on captured iron and on exogenous porphyrin is manifest as an absolute growth requirement for heme. A number of outer membrane proteins including some gingipains contain the hemoglobin receptor (HA2) domain. In cell surface extracts, polypeptides derived from HA2-containing proteins predominated in hemoglobin binding. The in vitro porphyrin-binding properties of a recombinant HA2 domain were investigated and found to be iron independent. Porphyrins that differ from protoporphyrin IX in only the vinyl aspect of the tetrapyrrole ring show comparable effects in competing with hemoglobin for HA2 and facilitate growth recovery. For some porphyrins which differ from protoporphyrin IX at both propionic acid side chains, the modification is detrimental in both these assays. Correlations of porphyrin competition and growth recovery imply that the HA2 domain acts as a high-affinity hemophore at the cell surface to capture porphyrin from hemoglobin. While some proteins involved with heme capture bind directly to the iron center, the HA2 domain of P. gingivalis recognizes heme by a mechanism that is solely porphyrin mediated.

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“…gingivalis possesses a number of factors of potential importance in the periodontal disease process. Among these factors are fimbriae (19,24,38,63,66), lipopolysaccharide (20), hemagglutinins (11,34,40,44,45), capsule (55,61), and proteases (1,9,42,43,59). The proteolytic capability of P. gingivalis strains is known; however, only recently have protease genes been cloned.…”

mentioning

confidence: 99%

Characterization of Porphyromonas gingivalis -Induced Degradation of Epithelial Cell Junctional Complexes

Katz¹,

Sambandam²,

Wu³

et al. 2000

Infect Immun

178

168

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Porphyromonas gingivalis is considered among the etiological agents of human adult periodontitis. Although in vitro studies have shown that P. gingivalis has the ability to invade epithelial cell lines, its effect on the epithelial barrier junctions is not known. Immunofluorescence analysis of human gingival epithelial cells confirmed the presence of tight-junction (occludin), adherens junction (E-cadherin), and cell-extracellular matrix junction (␤1-integrin) transmembrane proteins. These transmembrane proteins are expressed in Madin-Darby canine kidney (MDCK) cells. In addition, MDCK cells polarize and therefore serve as a useful in vitro model for studies on the epithelial cell barrier. Using the MDCK cell system, we examined the effect of P. gingivalis on epithelial barrier function. Exposure of the basolateral surfaces of MDCK cells to P. gingivalis (>10 9 bacteria/ml) resulted in a decrease in transepithelial resistance. Immunofluorescence microscopy demonstrated decreases in the amounts of immunoreactive occludin, E-cadherin, and ␤1-integrin at specific times which were related to a disruption of cell-cell junctions in MDCK cells exposed to basolateral P. gingivalis. Disruption of cell-cell junctions was also observed upon apical exposure to bacteria; however, the effects took longer than those seen upon basolateral exposure. Cell viability was not affected by either basolateral or apical exposure to P. gingivalis. Western blot analysis demonstrated hydrolysis of occludin, E-cadherin, and ␤1-integrin in lysates derived from MDCK cells exposed to P. gingivalis. Immunoprecipitated occludin and E-cadherin molecules from MDCK cell lysates were also degraded by P. gingivalis, suggesting a bacterial protease(s) capable of cleaving these epithelial junction transmembrane proteins. Collectively, these data suggest that P. gingivalis is able to invade the deeper structures of connective tissues via a paracellular pathway by degrading epithelial cell-cell junction complexes, thus allowing the spread of the bacterium. These results also indicate the importance of a critical threshold concentration of P. gingivalis to initiate epithelial barrier destruction.

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Characterization of the trypsin-like enzymes of Porphyromonas gingivalis W83 using a radiolabeled active-site-directed inhibitor

Cited by 44 publications

References 40 publications

Activation of protease-activated receptors by gingipains fromPorphyromonas gingivalis leads to platelet aggregation: a new trait in microbial pathogenicity

Activation of protease-activated receptors by gingipains fromPorphyromonas gingivalis leads to platelet aggregation: a new trait in microbial pathogenicity

Porphyrin-Mediated Cell Surface Heme Capture from Hemoglobin byPorphyromonas gingivalis

Characterization of Porphyromonas gingivalis -Induced Degradation of Epithelial Cell Junctional Complexes

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