title: Cell selectivity, mechanism of action and LPS-neutralizing activity of bovine myeloid antimicrobial peptide-18 (BMAP-18) and its analogs.
abstract: To develop novel antimicrobial peptides (AMPs) with improved cell selectivity and potent LPS-neutralizing activity, we synthesized an 18 N-terminal residues peptide (BAMP-18) of bovine myeloid antimicrobial peptide-27 (BMAP-27) and its analogs (BMAP-18-W, BMAP-18-L, BMAP-18-I and BMAP-18-f). BMAP-18 and its analogs displayed much higher cell selectivity (about 4-97-fold increased) as compared to parental BMAP-27 because of their decreased hemolytic activity and retained antimicrobial activity. BMAP-27 caused near-complete dye leakage from bacterial-membrane-mimicking vesicles even at very low concentration of 0.5μM, whereas BMAP-18 and its analogs induced very little dye leakage (less than 40%) even at 16μM. These peptides induced near-complete membrane depolarization of Staphylococcus aureus cells under their MIC (4μM). These results suggests that BMAP-18 and its analogs exhibit lethality toward microbes due to their ability to form small channels that permit the transit of ions or protons, but not molecules as large as calcein, and not by the membrane-disruption/perturbation mode. BMAP-18 and its analogs significantly inhibited nitric oxide (NO) production or tumor necrosis factor-α (TNF-α) release in LPS-stimulated mouse macrophage RAW264.7 cells at 10μM. In particular, BMAP-18-W showed LPS-neutralizing activity comparable to that of BMAP-27. There was a significant linear correlation between the increase in the hydrophobicity of peptides and LPS-neutralizing activity. Although BMAP-18-W has lower hydrophobicity than BMAP-18-L, it showed higher LPS-neutralizing activity as compared to BMAP-18-L. This result suggests other important parameters of AMPs may be involved in their LPS-neutralizing activity, as well as positive charge and hydrophobicity.
authors.affiliation: Department of Bio-Materials, Graduate School and Research Center for Proteineous Materials, Chosun University, Gwangju 501-759, Republic of Korea.
authors.forename: Eun Kyu
authors.initials: EK
authors.lastname: Lee
authors.forename: Yoon-Chang
authors.initials: YC
authors.lastname: Kim
authors.forename: Yong Hai
authors.initials: YH
authors.lastname: Nan
authors.forename: Song Yub
authors.initials: SY
authors.lastname: Shin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D002417:Cattle; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000096:biosynthesis; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D013045:Species Specificity; D055672:Static Electricity; D013329:Structure-Activity Relationship; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000096:biosynthesis
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; C102359:BMAP-27; D008070:Lipopolysaccharides; D010446:Peptide Fragments; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide