SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "hsv:(MEDICIN OCH HÄLSOVETENSKAP) hsv:(Medicinska och farmaceutiska grundvetenskaper) hsv:(Andra medicinska och farmaceutiska grundvetenskaper) ;pers:(Potempa Jan)"

Sökning: hsv:(MEDICIN OCH HÄLSOVETENSKAP) hsv:(Medicinska och farmaceutiska grundvetenskaper) hsv:(Andra medicinska och farmaceutiska grundvetenskaper) > Potempa Jan

  • Resultat 1-2 av 2
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Malm, Sven, et al. (författare)
  • Acquisition of Complement Inhibitor Serine Protease Factor I and Its Cofactors C4b-Binding Protein and Factor H by Prevotella intermedia.
  • 2012
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Infection with the Gram-negative pathogen Prevotella intermedia gives rise to periodontitis and a growing number of studies implies an association of P. intermedia with rheumatoid arthritis. The serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b-binding protein (C4BP) and Factor H (FH). Yet, the significance of complement inhibitor acquisition in P. intermedia infection and FI binding by Gram-negative pathogens has not been addressed. Here we show that P. intermedia isolates bound purified FI as well as FI directly from heat-inactivated human serum. FI bound to bacteria retained its serine protease activity as shown in degradation experiments with (125)I-labeled C4b. Since FI requires cofactors for its activity we also investigated the binding of purified cofactors C4BP and FH and found acquisition of both proteins, which retained their activity in FI mediated degradation of C3b and C4b. We propose that FI binding by P. intermedia represents a new mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases.
  •  
2.
  • Bielecka, Ewa, et al. (författare)
  • Peptidyl arginine deiminase from Porphyromonas gingivalis abolishes C5a activity.
  • 2014
  • Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 289:47, s. 32481-32487
  • Tidskriftsartikel (refereegranskat)abstract
    • Evasion of killing by the complement system, a crucial part of innate immunity, is a key evolutionary strategy of many human pathogens. A major etiological agent of chronic periodontitis, the Gram-negative bacterium Porphyromonas gingivalis produces a vast arsenal of virulence factors that compromise human defense mechanisms. One of these is peptidylarginine deiminase (PPAD), an enzyme unique to P. gingivalis among bacteria, which converts Arg residues in polypeptide chains into citrulline. Here, we report that PPAD citrullination of a critical C-terminal arginine of the anaphylatoxin C5a disabled the protein function. Treatment of C5a with PPAD in vitro resulted in decreased chemotaxis of human neutrophils and diminished calcium signaling in monocytic cell line U937 transfected with the C5a receptor (C5aR) and loaded with a fluorescent intracellular calcium probe: Fura 2-AM. Moreover, a low degree of citrullination of internal arginine residues by PPAD was also detected using mass spectrometry. Further, after treatment of C5 with outer membrane vesicles (OMVs) naturally shed by P. gingivalis we observed generation of C5a totally citrullinated at the C-terminal Arg74 residue (Arg74Cit). In stark contrast only native C5a was detected after treatment with PPAD-null OMVs. Our study suggests reduced antibacterial and proinflammatory capacity of citrullinated C5a, achieved via lower level of chemotactic potential of the modified molecule, and weaker cell activation. In the context of previous studies, which showed crosstalk between C5aR and toll-like receptors, as well as enhanced arthritis development in mice infected with PPAD expressing P. gingivalis, our findings support a crucial role of PPAD in the virulence of P. gingivalis.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-2 av 2

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy