The Critical Role of Tryptophan in the Antimicrobial Activity and Cell Toxicity of the Duck Antimicrobial Peptide DCATH
The Critical Role of Tryptophan in the Antimicrobial Activity and Cell Toxicity of the Duck Antimicrobial Peptide DCATH
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色氨酸在鸭抗菌肽 dCATH 抗菌活性和细胞毒性中的关键作用
DOI：
10.3389/fmicb.2020.01146
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发表时间：
2020-05-28
影响因子：
5.2
通讯作者：
Liu, Yueying
中科院分区：
文献类型：
--
作者：
Feng, Xingjun;Jin, Sanjun;Liu, Yueying
抗菌肽（AMP）因其潜在的新抗生素药物候选者而受到更多关注。 dCATH作为一种新鉴定的来自鸭的抗菌素AMP，具有广谱抗菌活性，但具有明显的毒性。为了探索具有降低细胞毒性和提高细胞选择性的 dCATH 衍生 AMP，设计了一系列 dCATH 的截短和色氨酸取代的肽。 dCATH的4位和17位（W4和W17）两个色氨酸（Trp）残基之一含有其中之一的截短肽dCATH（1-16）和dCATH（5-20）显示出较强的抗菌活性，但没有表现出明显的溶血活性和细胞毒性。不含Trp的衍生肽不具有明显的抗菌活性，其溶血和细胞毒作用也减弱。 Trp荧光实验也证明W4和W17的存在对于dCATH的抗菌活性、溶血和细胞毒性至关重要，并且这两个Trp残基之一对于保留其抗菌活性是有能力和必要的。抗菌机制分析表明dCATH(1-16)和dCATH(5-20)通过增加通透性并导致膜完整性丧失来杀死细菌细胞。 dCATH(1-16) 和 dCATH(5-20) 对用 LPS 处理的 RAW 264.7 细胞中的 IL-6、TNF-α 和 NO 水平具有微弱的抑制活性。在体内，腹膜内施用这两种肽可显着降低死亡率，并为接受致死剂量 LPS 攻击的小鼠提供针对 LPS 诱导的炎症的保护。 dCATH(1-16)和dCATH(5-20)这两种肽具有较高的抗菌活性和细胞选择性，可能预示着未来作为新型抗菌剂的发展前景。
Antimicrobial peptides (AMPs) have attracted more attention for their potential candidates for new antibiotic drugs. As a novel identified cathelicidin AMP from duck, dCATH owns broad-spectrum antimicrobial activities but with a noticeable toxicity. To explore dCATH-derived AMPs with reduced cell toxicity and improved cell selectivity, a series of truncated and tryptophan-replaced peptides of dCATH were designed. Two truncated peptides containing one of the two tryptophan (Trp) residues at the positions of 4 and 17 (W4 and W17) of dCATH, dCATH(1-16) and dCATH(5-20), showed strong antibacterial activity, but didn't show obvious hemolytic activity and cytotoxicity. The derived peptides not containing Trp didn't possess obvious antimicrobial activity, and their hemolytic and cytotoxic effect was also diminished. Also as evidence by Trp fluorescence experiment that existence of W4 and W17 was crucially important to the antimicrobial activity, hemolysis and cytotoxicity of dCATH, and one of the two Trp residues was competent and necessary to retain its antimicrobial activity. Antibacterial mechanism analysis showed that dCATH(1-16) and dCATH(5-20) killed bacterial cells by increasing permeability and causing a loss of membrane integrity. dCATH(1-16) and dCATH(5-20) possessed insignificant inhibitory activity against levels of IL-6, TNF-alpha, and NO in RAW 264.7 cells treated with LPS.In vivo, intraperitoneal administration of the two peptides significantly decreased mortality and provided protection against LPS-induced inflammation in mice challenged with lethal dose of LPS. The two peptides, dCATH(1-16) and dCATH(5-20), which possessed high antibacterial activity and cell selectivity, may herald development prospects as new antibacterial agents in the future.