Potent bactericidal activity of reduced cryptdin-4 derived from its hydrophobicity and mediated by bacterial membrane disruption
Potent bactericidal activity of reduced cryptdin-4 derived from its hydrophobicity and mediated by bacterial membrane disruption
复制标题
DOI：
10.1007/s00726-021-03115-3
复制
发表时间：
2022-01-17
期刊：
影响因子：
3.5
通讯作者：
Aizawa，Tomoyasu
中科院分区：
文献类型：
--
作者：
Sato，Yuji;Wang，Yi;Aizawa，Tomoyasu
防御素是一种富含半胱氨酸的抗菌肽，在正常氧化条件下具有三个二硫键。Cryptdin-4（Crp 4）是小鼠小肠Paneth细胞分泌的一种防御素，只有还原型Crp 4（Crp 4 red）显示出抗肠道细菌的活性，尽管氧化型Crp 4（Crp 4 ox）和Crp 4 red都可以杀死非肠道细菌。为了研究影响Crp 4 red有效抗菌活性的分子因素，评估了Crp 4 ox和Crp 4 red、所有Cys残基被Ser肽取代的Crp 4（6C/S-Crp 4）和所有巯基被N-乙基马来酰亚胺修饰的Crp 4（NEM-Crp 4）的杀菌活性。所有肽均显示出对非肠道细菌的杀菌活性，而Crp 4 red和NEM-Crp 4显示出对肠道细菌的杀菌活性。这些有效的肽表现出高疏水性，这是强烈相关的膜插入。有趣的是，Crp 4与细菌的膜表面形成静电相互作用，即使没有发挥杀菌活性。此外，氧化和还原形式的Crp 4的杀菌活性被废除的静电相互作用的抑制，这一发现表明，Crp 4 redtargets细菌膜。最后，针对从细菌中提取的脂质的脂质体渗漏测定证明与杀菌活性相关。这些结果表明，Crp 4 redis的有效杀菌活性来自其疏水性，杀菌机制涉及破坏细菌膜。这项研究的结果提供了一个更好的理解Crp 4 ox和Crp 4 red的杀菌机制。
Defensin is a cysteine-rich antimicrobial peptide with three disulphide bonds under normal oxidative conditions. Cryptdin-4 (Crp4) is a defensin secreted by Paneth cells in the small intestine of mice, and only reduced Crp4 (Crp4red) shows activity against enteric commensal bacteria, although both oxidised Crp4 (Crp4ox) and Crp4redcan kill non-commensal bacteria. To investigate the molecular factors that affect the potent antimicrobial activity of Crp4red, the bactericidal activities of Crp4oxand Crp4red, Crp4 with all Cys residues substituted with Ser peptide (6C/S-Crp4), and Crp4 with all thiol groups modified by N-ethylmaleimide (NEM-Crp4) were assessed. All peptides showed bactericidal activity against non-commensal bacteria, whereas Crp4redand NEM-Crp4 showed bactericidal activity against commensal bacteria. These potent peptides exhibited high hydrophobicity, which was strongly correlated with membrane insertion. Intriguingly, Crp4oxformed electrostatic interactions with the membrane surface of bacteria, even without exerting bactericidal activity. Moreover, the bactericidal activity of both oxidised and reduced forms of Crp4 was abolished by inhibition of electrostatic interactions; this finding suggests that Crp4redtargets bacterial membranes. Finally, a liposome leakage assay against lipids extracted from commensal bacteria demonstrated a correlation with bactericidal activity. These results suggest that the potent bactericidal activity of Crp4redis derived from its hydrophobicity, and the bactericidal mechanism involves disruption of the bacterial membrane. Findings from this study provide a better understanding of the bactericidal mechanism of both Crp4oxand Crp4red.