title: Modulation of the activity of secretory phospholipase A2 by antimicrobial peptides.
abstract: The antimicrobial peptides magainin 2, indolicidin, and temporins B and L were found to modulate the hydrolytic activity of secretory phospholipase A(2) (sPLA(2)) from bee venom and in human lacrimal fluid. More specifically, hydrolysis of phosphatidylcholine (PC) liposomes by bee venom sPLA(2) at 10 micro M Ca(2+) was attenuated by these peptides while augmented product formation was observed in the presence of 5 mM Ca(2+). The activity of sPLA(2) towards anionic liposomes was significantly enhanced by the antimicrobial peptides at low [Ca(2+)] and was further enhanced in the presence of 5 mM Ca(2+). Similarly, with 5 mM Ca(2+) the hydrolysis of anionic liposomes was enhanced significantly by human lacrimal fluid sPLA(2), while that of PC liposomes was attenuated. These results indicate that concerted action of antimicrobial peptides and sPLA(2) could improve the efficiency of the innate response to infections. Interestingly, inclusion of a cationic gemini surfactant in the vesicles showed an essentially similar pattern on sPLA(2) activity, suggesting that the modulation of the enzyme activity by the antimicrobial peptides may involve also charge properties of the substrate surface.
authors.affiliation: Helsinki Biophysics & Biomembrane Group, Institute of Biomedicine, FIN-00014 University of Helsinki, Finland.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Zhao
authors.forename: Paavo K J
authors.initials: PK
authors.lastname: Kinnunen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology; D001514:Bee Venoms / Q000201:enzymology; D001516:Bees; D002614:Chelating Agents / Q000494:pharmacology; D004357:Drug Synergism; D004492:Edetic Acid / Q000494:pharmacology; D054501:Group II Phospholipases A2; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D008081:Liposomes / Q000737:chemistry; D054806:Magainins; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D011506:Proteins / Q000494:pharmacology; D013501:Surface-Active Agents / Q000494:pharmacology; D013666:Tears / Q000201:enzymology; D029867:Xenopus Proteins
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D001514:Bee Venoms; D002614:Chelating Agents; D008081:Liposomes; D054806:Magainins; D011506:Proteins; D013501:Surface-Active Agents; D029867:Xenopus Proteins; C104501:temporin; C073143:indolicidin; C053301:magainin 2 peptide, Xenopus; D004492:Edetic Acid; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2