title: Neutrophil-mediated proteolysis. Differential roles for cathepsin G and elastase.
abstract: In this study, we assessed the underlying mechanisms by which proteinases released from activated neutrophils mediate fibronectin degradation. Purified human neutrophils (1 x 10(6)) were incubated for 1 hr with 1 microM PMA in the absence or presence of different proteinase inhibitors in 96-well microtiter plates that were coated with 125I-labeled fibronectin (FN). PMA-activated neutrophils caused 85% of FN to be degraded (versus 5% under control conditions). A selective inhibitor of elastase (L658,758), a monoclonal antibody directed against human neutrophilic elastase, and plasma all reduced the neutrophil-mediated FN degradation by 60%. A monoclonal antibody directed against the neutrophil adhesion glycoprotein CD11/CD18 increased the antiproteolytic effect of plasma to 70% but had no effect on the other anti-elastase agents, suggesting that the subjacent space formed by adherent neutrophils restricted to a small degree plasma derived antiproteinases. Agents that blocked cathepsin G or cathepsin G and elastase completely prevented the proteolysis associated with PMA-stimulated neutrophils, suggesting that the actions of elastase may be dependent on the presence of biologically active cathepsin G.
authors.affiliation: Department of Medical Physiology, University of Calgary, Alberta, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Kubes
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.forename: M D
authors.initials: MD
authors.lastname: Grisham
authors.forename: D N
authors.initials: DN
authors.lastname: Granger
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000502:physiology*; D002511:Cephalosporins; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D019272:Leukocyte Elastase; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010196:Pancreatic Elastase / Q000276:immunology / Q000502:physiology*; D011759:Pyrrolidines / Q000494:pharmacology; D012697:Serine Endopeptidases; D015843:Serpins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000911:Antibodies, Monoclonal; D002511:Cephalosporins; D005353:Fibronectins; D011759:Pyrrolidines; D015843:Serpins; C065332:L 658758; C082205:N-benzyloxycarbonylglycyl-leucyl-phenylalanine chloromethyl ketone; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase; D013755:Tetradecanoylphorbol Acetate