title: Canine cathelicidin (K9CATH): gene cloning, expression, and biochemical activity of a novel pro-myeloid antimicrobial peptide.
abstract: Cathelicidins, a group of cationic peptides found in leukocytes and epithelial cells, play a central role in the early innate immune defense against infection. Although these host defense peptides have been reported in several mammalian species, including primates, no cathelicidins have been identified in carnivores. Here we report the cloning, tissue expression and biological activity of a novel canine cathelicidin (K9CATH). The full-length cDNA sequence of K9CATH encodes a predicted 172 amino acid pre-propeptide that is 60-70% similar to other mammalian cathelicidins. Mass spectrometry analysis confirmed that the 38 aa mature K9CATH peptide was present in neutrophil granule contents. Synthetic K9CATH displayed broad antimicrobial activity against Gram-positive bacteria (Listeria monocytogenes, and Staphylococcus aureus; MICs (minimal inhibitory concentrations) 0.5 and 50 microM, respectively), Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Salmonella serotype Typhimurium, Pseudomonas aeruginosa, Proteus mirabilis; MICs 1.25 microM, Salmonella serotype Enteritidis; MIC 0.5 microM, and Neisseria gonorrhoeae; MIC 0.06 microM), and yeast (Candida albicans; MIC 12.5-50 microM). K9CATH demonstrated high antimicrobial activity against Ureaplasma canigenitalium, and lower activity against Ureaplasma urealyticum (MIC 0.06 and 50 microM, respectively). Similar to its ovine congener SMAP-29, K9CATH possesses salt-independent antimicrobial activity and LPS binding capacity. K9CATH displayed minimal hemolytic activity against human, dog and chicken erythrocytes. The potency and broad antimicrobial activity of K9CATH suggest that this peptide may act as a fundamental contributor to the innate immune responses in this carnivore species.
authors.affiliation: Department of Anatomy, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Sang
authors.forename: M
authors.initials: M
authors.lastname: Teresa Ortega
authors.forename: Kristina
authors.initials: K
authors.lastname: Rune
authors.forename: Wang
authors.initials: W
authors.lastname: Xiau
authors.forename: Guolong
authors.initials: G
authors.lastname: Zhang
authors.forename: Jose L
authors.initials: JL
authors.lastname: Soulages
authors.forename: Gerald H
authors.initials: GH
authors.lastname: Lushington
authors.forename: Jianwen
authors.initials: J
authors.lastname: Fang
authors.forename: Todd D
authors.initials: TD
authors.lastname: Williams
authors.forename: Frank
authors.initials: F
authors.lastname: Blecha
authors.forename: Tonatiuh
authors.initials: T
authors.lastname: Melgarejo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D054804:Cathelicidins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D003001:Cloning, Molecular; D004285:Dogs / Q000235:genetics* / Q000276:immunology; D015870:Gene Expression; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006461:Hemolysis; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology*; D017433:Protein Structure, Secondary; D016415:Sequence Alignment
chemical_list: D054804:Cathelicidins; D008070:Lipopolysaccharides