Gene Engineering Laboratory, Feed Research Institute, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie St., Haidian District, Beijing, 100081, People's Republic of China.
Key Laboratory of Feed Biotechnology, Ministry of Agriculture and Rural Affairs, Beijing, 100081, People's Republic of China.
Appl Microbiol Biotechnol. 2021 Aug;105(14-15):5845-5859. doi: 10.1007/s00253-021-11454-0. Epub 2021 Jul 28.
There is an urgent need to explore new antimicrobial agents due to the looming threat of bacteria resistance. Bovine lactoferricin (LfcinB), as a multifunctional peptide, has the potential to be a new active drug in the future. In this study, it aims to investigate the effect of fatty acid conjugation on antimicrobial peptide activity and topical therapeutic efficacy in a mouse model infected with Staphylococcus hyicus. Both Lfcin4 and Lfcin5 were conjugated with the unsaturated fatty acid linoleic acid (18-C) at their N-terminus and modified by acylation at the C-terminus. The derived peptides of Lin-Lf4NH2 and Lin-Lf5NH2 showed better antibacterial activity (MICs of 3.27 to 6.64 μM) than their parent peptides (MICs of 1.83 to 59.57 μM). Lin-Lf4NH2 (63.2%, 5 min) and Lin-Lf5NH2 (35.8%, 5 min) could more rapidly penetrate bacterial membrane than Lf4NH2 (2.34%, 5 min) and Lf5NH2 (1.94%, 5 min), which further confirmed by the laser scanning confocal microscopy (LSCM). Electron microscopy observations showed Lin-Lf4NH2 and Lin-Lf5NH2 disrupted S. hyicus cell membranes and led to the leakage of contents. Furthermore, after treatment with Lin-Lf4NH2 and Lin-Lf5NH2, the abscess symptoms of mice were significantly alleviated; the recovery rate of abscesses scope of Lin-Lf4NH2 (73.25%) and Lin-Lf5NH2 (71.71%) were 38.8 and 37.9-fold higher than that of untreated group (1.89%), respectively, and superior to Lf4NH2 (46.87%) and Lf5NH2 (58.75%). They significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and chemokine (MCP-1) in S. hyicus skin lesions. This study provides evidence that conjugation of a fatty acid to antimicrobial peptides can improve the activity and have potential for topical therapeutic of S. hyicus skin infections. KEY POINTS: • Lin-Lfcin4NH2/Lfcin5NH2 showed stronger antimicrobial activity than parent peptides. • Lin-Lfcin4NH2/Lfcin5NH2 had a more effective ability to destroy bacterial membranes. • Lin-Lfcin4NH2/Lfcin5NH2 showed a topically higher efficacy than parent peptides.
由于细菌耐药性的迫在眉睫的威胁，迫切需要探索新的抗菌剂。牛乳铁蛋白（LfcinB）作为一种多功能肽，具有成为未来新型活性药物的潜力。本研究旨在探讨脂肪酸缀合对金黄色葡萄球菌感染小鼠模型中抗菌肽活性和局部治疗效果的影响。Lfcin4 和 Lfcin5 均在其 N 末端与不饱和脂肪酸亚油酸（18-C）缀合，并在 C 末端通过酰化修饰。衍生的肽 Lin-Lf4NH2 和 Lin-Lf5NH2 显示出比其母体肽（MIC 为 1.83 至 59.57 μM）更强的抗菌活性（MIC 为 3.27 至 6.64 μM）。Lin-Lf4NH2（63.2%，5 分钟）和 Lin-Lf5NH2（35.8%，5 分钟）比 Lf4NH2（2.34%，5 分钟）和 Lf5NH2（1.94%，5 分钟）更快地穿透细菌膜，这进一步通过激光扫描共聚焦显微镜（LSCM）得到证实。电子显微镜观察显示，Lin-Lf4NH2 和 Lin-Lf5NH2 破坏了金黄色葡萄球菌的细胞膜，并导致内容物泄漏。此外，用 Lin-Lf4NH2 和 Lin-Lf5NH2 处理后，小鼠的脓肿症状明显缓解；Lin-Lf4NH2（73.25%）和 Lin-Lf5NH2（71.71%）的脓肿范围恢复率分别比未处理组（1.89%）高 38.8 和 37.9 倍，优于 Lf4NH2（46.87%）和 Lf5NH2（58.75%）。它们显著降低了金黄色葡萄球菌皮肤病变中的细菌负荷和促炎细胞因子（TNF-α、IL-6 和 IL-1β）和趋化因子（MCP-1）的水平。本研究提供的证据表明，将脂肪酸与抗菌肽缀合可以提高活性，并具有金黄色葡萄球菌皮肤感染的局部治疗潜力。关键点： • Lin-Lfcin4NH2/Lfcin5NH2 比亲本肽显示出更强的抗菌活性。 • Lin-Lfcin4NH2/Lfcin5NH2 具有更强的破坏细菌膜的能力。 • Lin-Lfcin4NH2/Lfcin5NH2 比亲本肽具有更高的局部疗效。
