Plectasin has antibacterial activity and no affect on cell viability or IL-8 production

• Published in: Biochemical and biophysical research communications Vol. 374; no. 4; pp. 709 - 713
• Main Authors: Hara, Shintaro, Mukae, Hiroshi, Sakamoto, Noriho, Ishimoto, Hiroshi, Amenomori, Misato, Fujita, Hanako, Ishimatsu, Yuji, Yanagihara, Katsunori, Kohno, Shigeru
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.10.2008
• Subjects: A549 cell; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Bronchi - drug effects; Cell Line; Cell Survival - drug effects; Cytokine induction; Cytotoxicity; Defensin; Defensins - pharmacology; Epithelial Cells - drug effects; Human defensins; Human neutrophil peptide-1; Humans; Interleukin-8 - biosynthesis; Interleukin-8 induction; Microbial Sensitivity Tests; Normal human bronchial epithelial cell; Normal human lung fibroblast; Peptides - pharmacology; Plectasin; Protein Biosynthesis - drug effects; RNA, Messenger - biosynthesis; Streptococcus pneumoniae; Streptococcus pneumoniae - drug effects; A549 cell; Cytokine induction; Normal human bronchial epithelial cell; Interleukin-8 induction; Plectasin; Normal human lung fibroblast; Antibacterial activity; Cytotoxicity; Human neutrophil peptide-1; Human defensins; Defensin
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2008.07.093

Animals and plants express endogenous peptide antibiotics called defensins. Defensins show broad-spectrum antimicrobial activity, even against bacteria that have resistance to conventional antibiotics, which has made them viable candidates for new antibiotics. However, human defensins have failed to reach the market because of their cytotoxic effects and non-antimicrobial bioactivities. Plectasin is a defensin that has shown promise but has not had its potentially negative effects clarified. To address this issue, we examined plectasin’s cytotoxicity in human cells using an AlamarBlue reduction assay, its interleukin (IL)-8-inducing capacity using real-time PCR and ELISA, and measured its MIC against bacteria. We confirmed that plectasin has specific antibacterial activity against Streptococcus pneumoniae. Plectasin showed no cytotoxicity to A549 cells, normal human bronchial epithelial cells, or lung fibroblasts, and it did not induce IL-8 transcription or production in A549 cells. Our results suggest that plectasin could be an inoffensive alternative antibiotic for clinical application.