title: Divergent effects of alpha1-antitrypsin on neutrophil activation, in vitro.
abstract: alpha1-Antitrypsin (AAT) is a major circulating serine proteinase inhibitor in humans. The anti-proteinase activity of AAT is inhibited by chemical modification. These include inter- or intramolecular polymerisation, oxidation, complex formation with target proteinases (e.g., neutrophil elastase), and/or cleavage by multi-specific proteinases. In vivo, several modified forms of AAT have been identified which stimulate biological activity in vitro unrelated to inhibition of serine proteinases. In this study we have examined the effects of native and polymerised AAT and C-36 peptide, a proteolytic cleavage product of AAT, on human neutrophil activation, in vitro. We show that the C-36 peptide displays striking concentration-dependent pro-inflammatory effects on human neutrophils, including induction of neutrophil chemotaxis, adhesion, degranulation, and superoxide generation. In contrast to C-36 peptide, native and polymerised AAT at similar and higher concentrations showed no effects on neutrophil activation. These results suggest that cleavage of AAT may not only abolish its proteinase inhibitor activity, but can also generate a powerful pro-inflammatory activator for human neutrophils.
authors.affiliation: Department of Medicine, University Hospital Malmö, Malmö, S-20502, Sweden. sabina.janciauskiene@medforsk.mas.lu.se
authors.forename: Sabina
authors.initials: S
authors.lastname: Janciauskiene
authors.forename: Inga
authors.initials: I
authors.lastname: Zelvyte
authors.forename: Lennart
authors.initials: L
authors.lastname: Jansson
authors.forename: Tim
authors.initials: T
authors.lastname: Stevens
mesh_terms: D000838:Anions; D002448:Cell Adhesion; D002450:Cell Communication; D002478:Cells, Cultured; D002633:Chemotaxis; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D007249:Inflammation; D019272:Leukocyte Elastase; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D009195:Peroxidase / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D000515:alpha 1-Antitrypsin / Q000378:metabolism*
chemical_list: D000838:Anions; D010455:Peptides; D015842:Serine Proteinase Inhibitors; D000515:alpha 1-Antitrypsin; D013481:Superoxides; D009195:Peroxidase; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase; D020780:Matrix Metalloproteinase 9