Zhu Xin, Shan Anshan, Ma Zhi, Xu Wei, Wang Jiajun, Chou Shuli, Cheng Baojing
Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China.
Institute of Animal Nutrition, Northeast Agricultural University, Harbin, China
Antimicrob Agents Chemother. 2015;59(6):3008-17. doi: 10.1128/AAC.04830-14. Epub 2015 Mar 9.
The antipseudomonal efficiency and mechanism of action of a novel engineered antimicrobial peptide, T9W, were evaluated in this study. T9W displayed high activity, with a lethal concentration (LC) of 1 to 4 μM against Pseudomonas aeruginosa, including against ciprofloxacin-, gentamicin-, and ceftazidime-resistant strains, even in the presence of 50 to 300 mM NaCl, 1 to 5 mM Ca(2+), or 0.5 to 2 mM Mg(2+). The time-kill curve (TKC) analysis demonstrated concentration-dependent activity, with T9W achieving complete killing in less than 30 min at 1× LC and in less than 5 min at 4× LC. Combination TKC analyses additionally demonstrated a synergistic effect with ciprofloxacin and gentamicin. The selectivity of T9W was further supported by its ability to specifically eliminate P. aeruginosa in a coculture with macrophages without toxicity to the mammalian cells. The results from fluorescent measurement indicated that T9W bound to lipopolysaccharide (LPS) and induced P. aeruginosa membrane depolarization, and microscopic observations and flow cytometry further indicated that T9W targeted the P. aeruginosa cell membrane and disrupted cytoplasmic membrane integrity, thereby causing cellular content release leading to cell death. This study revealed the potential usefulness of T9W as a novel antimicrobial agent against P. aeruginosa.
本研究评估了一种新型工程抗菌肽T9W的抗铜绿假单胞菌效率及作用机制。T9W表现出高活性，对铜绿假单胞菌的致死浓度（LC）为1至4 μM，包括对环丙沙星、庆大霉素和头孢他啶耐药菌株，即使在存在50至300 mM NaCl、1至5 mM Ca(2+)或0.5至2 mM Mg(2+)的情况下也是如此。时间-杀菌曲线（TKC）分析表明其具有浓度依赖性活性，T9W在1×LC时不到30分钟即可实现完全杀菌，在4×LC时不到5分钟即可实现完全杀菌。联合TKC分析还表明T9W与环丙沙星和庆大霉素具有协同作用。T9W能够在与巨噬细胞的共培养物中特异性消除铜绿假单胞菌而对哺乳动物细胞无毒性，这进一步支持了其选择性。荧光测量结果表明T9W与脂多糖（LPS）结合并诱导铜绿假单胞菌膜去极化，显微镜观察和流式细胞术进一步表明T9W靶向铜绿假单胞菌细胞膜并破坏细胞质膜完整性，从而导致细胞内容物释放，进而导致细胞死亡。本研究揭示了T9W作为一种新型抗铜绿假单胞菌抗菌剂的潜在用途。
