Copper regulates the interactions of antimicrobial piscidin peptides from fish mast cells with formyl peptide receptors and heparin
Copper regulates the interactions of antimicrobial piscidin peptides from fish mast cells with formyl peptide receptors and heparin
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DOI：
10.1074/jbc.ra118.001904
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发表时间：
2018-10-05
影响因子：
4.8
通讯作者：
Cotten, Myriam L.
中科院分区：
文献类型：
--
作者：
Kim, So Young;Zhang, Fuming;Cotten, Myriam L.
鱼类的吞噬细胞分泌抗菌肽（AMP），如鱼素、糖胺聚糖（如肝素）和铜离子，作为一线免疫防御。最近，我们确定了 piscidins 1 (P1) 和 3 (P3) 与 Cu2+ 的配位增强了它们对膜和 DNA 的抗菌活性。有趣的是，我们注意到piscidins和其他AMP之间存在物理化学相似性，它们与肝素相互作用并通过参与先天免疫的甲酰肽受体（FPR）诱导免疫细胞趋化性。因此，我们假设 P1 和 P3 与肝素和 FPR 相互作用，但这些相互作用明显依赖于 Cu2+。在这里，我们研究了 piscidins、肝素、FPR 和 Cu2+ 增强的相互作用组。利用 FPR 转染的细胞和中性粒细胞，我们证明两种 piscidin 都专门使用 FPR1 和 FPR2 来诱导趋化性，而 Cu2+ 会降低其趋化性诱导。 P1 比 P3 和其他已知的 AMP 配体更有效地激活 FPR1。此外，这两种肽均下调中性粒细胞表面 Fpr2 的表达。肽的铜缀合不会进一步增加下调，表明金属诱导的构象变化转化为降低的 FPR 功效而不改变结合亲和力。利用表面等离振子共振，我们发现鱼素-肝素相互作用是 Cu2+ 依赖性的，并且在吞噬体的酸性 pH 下会减弱。虽然肝素会降低P3-Cu2+的抗菌活性，但并不影响P1-Cu2+对细菌的杀灭作用。铜对调节两种 piscidin 与 FPR 和肝素的微摩尔范围相互作用的作用表明，这些不同免疫剂的相互作用组在先天免疫中发挥着重要作用。这里发现的不同宿主防御分子之间的相互作用可能有助于设计治疗免疫相关疾病的新疗法。
Phagocytic cells in fish secrete antimicrobial peptides (AMPs) such as piscidins, glycosaminoglycans such as heparin, and copper ions as first-line immune defenses. Recently, we established that Cu2+ coordination by piscidins 1 (P1) and 3 (P3) enhances their antibacterial activity against membranes and DNA. Interestingly, we noted that physicochemical similarities exist between both piscidins and other AMPs that interact with heparin and induce immune-cell chemotaxis through formyl peptide receptors (FPRs) involved in innate immunity. Thus, we postulated that P1 and P3 interact with heparin and FPRs but that these interactions distinctively depend on Cu2+. Here, we investigate the interactome potentiated by piscidins, heparin, FPR, and Cu2+. Utilizing FPR-transfected cells and neutrophils, we demonstrate that both piscidins exclusively use FPR1 and FPR2 to induce chemotaxis and that Cu2+ reduces their chemotaxis induction. P1 is more effective at activating FPR1 than P3 and other known AMP ligands. Furthermore, the expression of Fpr2 on the surface of neutrophils is down-regulated by both peptides. Copper conjugation of the peptides does not further increase down-regulation, suggesting that the conformational changes induced by the metal translate into reduced FPR efficacy without altering the binding affinity. Using surface plasmon resonance, we show that piscidin-heparin interactions are Cu2+-dependent and reduced at the acidic pH of phagosomes. Although heparin decreases the antimicrobial activity of P3-Cu2+, it does not affect bacterial killing by P1-Cu2+. Copper's effects on modulating the micromolar-range interactions of both piscidins with FPR and heparin suggest that the interactome of these distinct immune agents plays an important role in innate immunity. The interactions between diverse host-defense molecules uncovered here may help inform the design of novel therapeutics to treat immune-related diseases.