The Peptide Sequence of Diacyl Lipopeptides Determines Dendritic Cell TLR2-Mediated NK Activation
The Peptide Sequence of Diacyl Lipopeptides Determines Dendritic Cell TLR2-Mediated NK Activation
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DOI：
10.1371/journal.pone.0012550
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发表时间：
2010-09-02
期刊：
影响因子：
3.7
通讯作者：
Seya, Tsukasa
中科院分区：
文献类型：
--
作者：
Azuma, Masahiro;Sawahata, Ryoko;Seya, Tsukasa
自然杀伤 (NK) 细胞是淋巴细胞效应细胞，被激活以控制某些微生物感染和肿瘤。许多 NK 激活和调节受体参与调节 NK 细胞功能。此外，幼稚 NK 细胞的激活从根本上是由细胞因子或髓样树突状细胞 (mDC) 以各种模式触发的。在这项研究中，我们合成了 16 个 S[2,3-双（棕榈酰）丙基]半胱氨酸（Pam2Cys）脂肽，其序列是根据金黄色葡萄球菌脂蛋白设计的，并使用小鼠（C57BL/6）骨髓来源的 DC（BMDC）和 NK 细胞评估了它们的功能特性。 NK 细胞活化通过三个标准进行评估：IFN-γ 产生、NK 活化标记物和细胞因子的上调以及 NK 靶标（B16D8 细胞）细胞毒性。二酰化脂肽充当 TLR2 配体，诱导 CD25/CD69/CD86、IL-6 和 IL-12p40 上调，这代表 BMDC 的成熟。引人注目的是，Pam2Cys 脂肽根据这些标准诱导小鼠 NK 细胞活化。 Pam2Cys 肽刺激的 BMDC 和 NK 细胞进行细胞间接触，而不是受刺激的 BMDC 释放的可溶性介体诱导 NK 细胞的激活。对于大多数脂肽来说，BMDC TLR2/MyD88 通路负责驱动 NK 激活，而一些脂肽则通过 NK 细胞中的 TLR2/MyD88 通路轻微诱导 NK 细胞直接激活。 NK 激活的潜力受到肽一级序列的严格调节。靠近 N 末端脂质部分的疏水性或含脯氨酸序列会干扰脂肽诱导 BMDC 介导的 NK 激活的能力。这种 NK 激活模式与 PolyI:C 诱导的激活模式明显不同，后者与 BMDC 的 I 型 IFN 诱导途径密切相关。这些结果表明 BMDC 的 MyD88 途径控制着另一种 NK 激活途径，其中 TLR2 激动性脂肽的肽序列严重影响 NK 激活的潜力。
Natural killer (NK) cells are lymphocyte effectors that are activated to control certain microbial infections and tumors. Many NK-activating and regulating receptors are involved in regulating NK cell function. In addition, activation of naive NK cells is fundamentally triggered by cytokines or myeloid dendritic cells (mDC) in various modes. In this study, we synthesized 16 S[ 2,3-bis(palmitoyl) propyl] cysteine (Pam2Cys) lipopeptides with sequences designed from lipoproteins of Staphylococcus aureus, and assessed their functional properties using mouse (C57BL/6) bone marrow-derived DC (BMDC) and NK cells. NK cell activation was evaluated by three criteria: IFN-gamma production, up-regulation of NK activation markers and cytokines, and NK target (B16D8 cell) cytotoxicity. The diacylated lipopeptides acted as TLR2 ligands, inducing up-regulation of CD25/CD69/CD86, IL-6, and IL-12p40, which represent maturation of BMDC. Strikingly, the Pam2Cys lipopeptides induced mouse NK cell activation based on these criteria. Cell-cell contact by Pam2Cys peptide-stimulated BMDC and NK cells rather than soluble mediators released by stimulated BMDC induced activation of NK cells. For most lipopeptides, the BMDC TLR2/MyD88 pathway was responsible for driving NK activation, while some slightly induced direct activation of NK cells via the TLR2/MyD88 pathway in NK cells. The potential for NK activation was critically regulated by the peptide primary sequence. Hydrophobic or proline-containing sequences proximal to the N-terminal lipid moiety interfered with the ability of lipopeptides to induce BMDC-mediated NK activation. This mode of NK activation is distinctly different from that induced by polyI:C, which is closely associated with type I IFN-inducing pathways of BMDC. These results imply that the MyD88 pathway of BMDC governs an alternative NK-activating pathway in which the peptide sequence of TLR2-agonistic lipopeptides critically affects the potential for NK activation.