Antimicrobial activity of trout hepcidin
Antimicrobial activity of trout hepcidin
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DOI：
10.1016/j.fsi.2014.04.013
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发表时间：
2014-11-01
影响因子：
4.7
通讯作者：
Mercado, Luis
中科院分区：
文献类型：
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作者：
Alvarez, Claudio A.;Guzman, Fanny;Mercado, Luis
铁调素是一种抗微生物肽，也是一种主要由肝脏产生的激素。它是一种富含半胱氨酸的肽，具有高度保守的β折叠结构。最近，我们描述了铁调素在虹鳟鱼肝脏中的表达以及铁超载和脂多糖（LPS）对铁调素表达的诱导。因此，在这项工作中，我们专注于分析与其氧化状态相关的肽构象在抗微生物活性中的重要性。该肽在还原状态下显示α-螺旋构象，在氧化状态下显示特征性β-折叠构象。抗微生物活性测定表明，氧化肽比还原肽更有效地对抗大肠杆菌和重要的鲑鱼病原体Piscirickettsia salmonis。此外，对暴露于与罗丹明偶联的鳟鱼铁调素的鲑鱼P. salmonis培养物的共聚焦分析揭示了该肽的细胞内位置，并且Sytox渗透测定表明膜破坏不是其抗微生物作用的机制。此外，在该肽的N-末端检测到保守的ATCUN基序。这个序列被描述为一个小的金属结合位点，与DNA切割有关。在这项工作中，我们证明，这种肽是能够诱导DNA水解抗坏血酸和CuCl 2的存在下。当使用具有截短的N-末端的变体进行相同的实验时，没有观察到DNA水解。我们的研究结果表明，铁调素的正确折叠是必需的，其抗菌活性和最有可能的金属结合位点（ATCUN基序）存在于其N-末端参与氧化损伤的大分子。(C)2014爱思唯尔有限公司版权所有。
Hepcidin is an antimicrobial peptide and a hormone produced mostly the liver. It is a cysteine-rich peptide with a highly conserved beta-sheet structure. Recently, we described the hepcidin expression in liver of rainbow trout and its inducibility by iron overloading and lipopolysaccharide (LPS). Thus, in this work, we focused in analyzing the importance of the peptide conformation associated to its oxidative state in the antimicrobial activity. This peptide showed a a-helix conformation in reduced state and the characteristic beta-sheet conformation in the oxidized state. Antimicrobial activity assays showed that the oxidized peptide is more effective than the reduced peptide against Escherichia coli and the important salmon fish pathogen Piscirickettsia salmonis. In addition, confocal analysis of P. salmonis culture exposed to trout hepcidin coupled with rhodamine revealed the intracellular location of this peptide and Sytox permeation assay showed that membrane disruption is not the mechanism of its antimicrobial action. Moreover, a conserved ATCUN motif was detected in the N-terminus of this peptide. This sequence has been described as a small metal-binding site that has been implicated in DNA cleavage. In this work we proved that this peptide is able to induce DNA hydrolysis in the presence of ascorbate and CuCl2. When the same experiments were carried out using a variant with truncated N-terminus no DNA hydrolysis was observed. Our results suggest that correct folding of hepcidin is required for its antimicrobial activity and most likely the metal-binding site (ATCUN motif) present in its N-terminus is involved in the oxidative damage to macromolecules. (C) 2014 Elsevier Ltd. All rights reserved.