title: Functional study of elafin cleaved by Pseudomonas aeruginosa metalloproteinases.
abstract: Elafin is a 6-kDa innate immune protein present at several epithelial surfaces including the pulmonary epithelium. It is a canonical protease inhibitor of two neutrophil serine proteases [neutrophil elastase (NE) and proteinase 3] with the capacity to covalently bind extracellular matrix proteins by transglutamination. In addition to these properties, elafin also possesses antimicrobial and immunomodulatory activities. The aim of the present study was to investigate the effect of Pseudomonas aeruginosa proteases on elafin function. We found that P. aeruginosa PAO1-conditioned medium and two purified Pseudomonas metalloproteases, pseudolysin (elastase) and aeruginolysin (alkaline protease), are able to cleave recombinant elafin. Pseudolysin was shown to inactivate the anti-NE activity of elafin by cleaving its protease-binding loop. Interestingly, antibacterial properties of elafin against PAO1 were found to be unaffected after pseudolysin treatment. In contrast to pseudolysin, aeruginolysin failed to inactivate the inhibitory properties of elafin against NE. Aeruginolysin cleaves elafin at the amino-terminal Lys6-Gly7 peptide bond, resulting in a decreased ability to covalently bind purified fibronectin following transglutaminase activity. In conclusion, this study provides evidence that elafin is susceptible to proteolytic cleavage at alternative sites by P. aeruginosa metalloproteinases, which can affect different biological functions of elafin.
authors.affiliation: Department of Medicine, Pulmonary Research Division, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Guyot
authors.forename: Gudmundur
authors.initials: G
authors.lastname: Bergsson
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Butler
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Greene
authors.forename: Sinéad
authors.initials: S
authors.lastname: Weldon
authors.forename: Efrat
authors.initials: E
authors.lastname: Kessler
authors.forename: Rodney L
authors.initials: RL
authors.lastname: Levine
authors.forename: Shane J
authors.initials: SJ
authors.lastname: O'Neill
authors.forename: Clifford C
authors.initials: CC
authors.lastname: Taggart
authors.forename: Noel G
authors.initials: NG
authors.lastname: McElvaney
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D053492:Elafin / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D045726:Metalloproteases / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D053492:Elafin; D005353:Fibronectins; D045726:Metalloproteases