Endogenous animal toxin-like human β-defensin 2 inhibits own K+ channels through interaction with channel extracellular pore region
Endogenous animal toxin-like human β-defensin 2 inhibits own K+ channels through interaction with channel extracellular pore region
复制标题
内源性动物毒素样人β-防御素 2 通过与通道细胞外孔区域相互作用抑制自身 K 通道
DOI：
10.1007/s00018-014-1715-z
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发表时间：
2015-02-01
影响因子：
8
通讯作者：
Wu, Yingliang
中科院分区：
文献类型：
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作者：
Yang, Weishan;Feng, Jing;Wu, Yingliang
人类钾离子通道被来自有毒动物的肽毒素广泛抑制。然而，迄今尚未发现人内源性肽抑制剂。在这项研究中，我们首次使用电生理技术证明，内源性人β-防御素2（hBD 2）能够选择性和剂量依赖性地抑制人电压门控Kv1.3通道在皮摩尔肽浓度。免疫共沉淀试验进一步支持hBD 2与Kv1.3通道的选择性结合。通过突变实验，我们发现Kv1.3通道的外孔结构域是hBD 2的结合位点，这与动物毒素抑制剂识别的Kv1.3通道的相互作用位点相似。hBD 2能够通过抑制人Jurkat细胞中的Kv1.3通道电流来抑制IL-2的产生，这进一步通过在这些细胞中Kv1.3敲低后hBD 2对IL-2产生的活性的缺乏来证实。更有趣的是，hBD 2也被发现有效地抑制Kv1.3通道电流，并抑制人原代CD 3（+）T细胞和健康供体或银屑病患者外周血单核细胞中IL-2的产生。我们的研究结果不仅证明hBD 2是第一个被鉴定的人钾通道内源性肽抑制剂，而且为研究新发现的hBD 2作为Kv1.3通道抑制剂在免疫系统和其他领域的功能奠定了基础。
Human potassium channels are widely inhibited by peptide toxins from venomous animals. However, no human endogenous peptide inhibitor has been discovered so far. In this study, we demonstrate for the first time using electrophysiological techniques, that endogenous human beta-defensin 2 (hBD2) is able to selectively and dose-dependently inhibit the human voltage-gated Kv1.3 channel at picomolar peptide concentration. The co-immunoprecipitation assays further supported the selective binding of hBD2 to Kv1.3 channel. Using mutagenesis experiments, we found that the outer pore domain of Kv1.3 channel was the binding site of hBD2, which is similar to the interacting site of Kv1.3 channel recognized by animal toxin inhibitors. The hBD2 was able to suppress IL-2 production through inhibition of Kv1.3 channel currents in human Jurkat cells, which was further confirmed by the lack of hBD2 activity on IL-2 production after Kv1.3 knockdown in these cells. More interestingly, hBD2 was also found to efficiently inhibit Kv1.3 channel currents and suppress IL-2 production in both human primary CD3(+) T cells and peripheral mononuclear cells from either healthy donors or psoriasis patients. Our findings not only evidenced hBD2 as the first characterized endogenous peptide inhibitor of human potassium channels, but also paved a promising avenue to investigate newly discovered function of hBD2 as Kv1.3 channel inhibitor in the immune system and other fields.