Pneumolysin induces release of matrix metalloproteinase-8 and -9 from human neutrophils.
The research question addressed in the current study was: does the pneumococcal pore-forming toxin, pneumolysin, mobilise matrix metalloproteinase (MMP) -8 and -9 from isolated human blood neutrophils at sublytic concentrations of 5, 10 and 20 ng.mL(-1)? MMPs were measured in the supernatants of unstimulated neutrophils and of cells exposed to pneumolysin and the chemoattractant N-formyl-L-methionyl-l-leucyl-l-phenylalanine (f-MLP; 0.1 microM), individually and in combination, using ELISA procedures, and alterations in cytosolic Ca(2+) concentrations were monitored using a fura-2 acetoxymethyl ester (fura-2/AM)-based spectrofluorimetric method. Treatment of neutrophils with pneumolysin alone caused dose-related release of both MMPs, whereas f-MLP caused modest increases; the combination of both activators was, however, most effective. Pneumolysin/f-MLP-activated release of the MMPs from the cells was paralleled by increases in cytosolic Ca(2+). Exposure of human neutrophils to pneumolysin is accompanied by mobilisation of MMPs, which is potentiated by f-MLP. If operative in vivo, pneumolysin-mediated release of MMPs from neutrophils and other cell types may contribute to the pathogenesis of severe pneumococcal disease.
Cockeran
R
R
Medical Research Council, Unit for Inflammation and Immunity, Dept of Immunology, University of Pretoria, Tshwane Academic Division of the National Health Laboratory Service, Pretoria. rcockera@medic.up.ac.za
Mitchell
T J
TJ
Feldman
C
C
Anderson
R
R
D001426:Bacterial Proteins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002630:Chemotactic Factors / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D016257:Fura-2 / Q000737:chemistry; D006801:Humans; D007249:Inflammation; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013301:Streptolysins / Q000494:pharmacology*
D001426:Bacterial Proteins; D002630:Chemotactic Factors; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae; D009240:N-Formylmethionine Leucyl-Phenylalanine; D020784:Matrix Metalloproteinase 8; D020780:Matrix Metalloproteinase 9; D002118:Calcium; D016257:Fura-2