title: The human fibrinolytic system is a target for the staphylococcal metalloprotease aureolysin.
abstract: The major opportunistic pathogen Staphylococcus aureus utilizes the human fibrinolytic system for invasion and spread via plasmin(ogen) binding and non-proteolytic activation. Because S. aureus secretes several proteases recently proposed as virulence factors, we explored whether these enzymes could add to the activation of the host's fibrinolytic system. Exposure of human pro-urokinase [pro-uPA (where uPA is urokinase-type plasminogen activator)] to conditioned growth media from staphylococcal reference strains results in an EDTA-sensitive conversion of the single-chain zymogen into its two-chain active form, an activity not observed in an aureolysin-deficient strain. Using purified aureolysin, we verified the capacity of this thermolysin-like metalloprotease to activate pro-uPA, with a 2.6 x 10(3) M(-1) x s(-1) catalytic efficiency. Moreover, activation also occurs in the presence of human plasma, as well as in conditioned growth media from clinical isolates. Finally, we establish that aureolysin (i) converts plasminogen into angiostatin and mini-plasminogen, the latter retaining its capacity to be activated by uPA and to hydrolyse fibrin, (ii) degrades the plasminogen activator inhibitor-1, and (iii) abrogates the inhibitory activity of alpha(2)-antiplasmin. Altogether, we propose that, in parallel with the staphylokinase-dependent activation of plasminogen, aureolysin may contribute significantly to the activation of the fibrinolytic system by S. aureus, and thus may promote bacterial spread and invasion.
authors.affiliation: Department of Obstetrics and Gynecology, Technical University of Munich, Ismaninger Str. 22, D-81675 Munich, Germany.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Beaufort
authors.forename: Piotr
authors.initials: P
authors.lastname: Wojciechowski
authors.forename: Christian P
authors.initials: CP
authors.lastname: Sommerhoff
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Szmyd
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Dubin
authors.forename: Sigrun
authors.initials: S
authors.lastname: Eick
authors.forename: Josef
authors.initials: J
authors.lastname: Kellermann
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmitt
authors.forename: Jan
authors.initials: J
authors.lastname: Potempa
authors.forename: Viktor
authors.initials: V
authors.lastname: Magdolen
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D017077:Culture Media, Conditioned; D017931:DNA Primers; D005342:Fibrinolysis; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases / Q000378:metabolism*; D045726:Metalloproteases / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D016133:Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000201:enzymology / Q000378:metabolism* / Q000472:pathogenicity; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D017931:DNA Primers; D017395:Plasminogen Activator Inhibitor 1; D045726:Metalloproteases; D014568:Urokinase-Type Plasminogen Activator; D008666:Metalloendopeptidases; C115504:aureolysin