title: Chemoattractant properties of PR-39, a neutrophil antibacterial peptide.
abstract: The proline-arginine (PR) -rich antibacterial peptide, PR-39, kills bacteria by a non-pore-forming mechanism. Because this neutrophil peptide possesses several distinct functional properties and because other antimicrobial peptides are chemoattractants, we sought to determine whether PR-39 was a chemoattractant for porcine leukocytes. The peptide was synthesized by the solid-phase method using t-Boc chemistry and purified by reversed-phase high-performance liquid chromatography. Leukocyte migration was assessed with the use of a 48-well microchemotaxis chamber. PR-39 induced the directed migration of neutrophils. The peak chemotaxis response occurred at 0.5-2 microM, which was slightly lower than the minimal inhibitory and bactericidal concentrations for PR-39. However, the peptide was not a chemoattractant for mononuclear cells. Truncation of PR-39 suggested that the neutrophil chemoattractant domain may be contained within the first 26 amino acid residues. Intracellular Ca2+ fluxes in response to PR-39 were monitored by flow cytometry and showed a transient increase that peaked at approximately 40 s and approached basal values by 4 min. However, in a Ca2+-free environment, the PR-39-induced Ca2+ increase was abrogated. Furthermore, PR-39 did not induce neutrophil chemotaxis in the absence of extracellular Ca2+, and pertussis toxin inhibited both neutrophil chemotaxis and Ca2+ mobilization. Taken together, these data suggest that PR-39 is a Ca2+-dependent chemoattractant of neutrophils. The finding of a neutrophil antibacterial peptide that is also a neutrophil chemoattractant is intriguing and may indicate an important role for PR-39 in inflammation.
authors.affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan 66506-5602, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Huang
authors.forename: C R
authors.initials: CR
authors.lastname: Ross
authors.forename: F
authors.initials: F
authors.lastname: Blecha
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000187:drug effects; D010455:Peptides / Q000494:pharmacology*; D037342:Pertussis Toxin; D013552:Swine; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D002630:Chemotactic Factors; D010455:Peptides; D010566:Virulence Factors, Bordetella; C072212:PR 39; D037342:Pertussis Toxin; D002118:Calcium