Microglial Zinc Uptake via Zinc Transporters Induces ATP Release and the Activation of Microglia
Microglial Zinc Uptake via Zinc Transporters Induces ATP Release and the Activation of Microglia
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DOI：
10.1002/glia.21235
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发表时间：
2011-12-01
期刊：
影响因子：
6.2
通讯作者：
Nagasawa, Kazuki
中科院分区：
文献类型：
--
作者：
Higashi, Youichirou;Segawa, Shohei;Nagasawa, Kazuki
以前，我们证明了细胞外锌通过依次激活NADPH氧化酶和聚（ADP-核糖）聚合酶（PARP）-1在短暂性全脑缺血诱导的小胶质细胞活化中起着关键作用。然而，目前尚不清楚锌如何引起小胶质细胞的顺序激活。在这里，我们研究转运蛋白介导的锌摄取是否是必要的小胶质细胞活化。向小胶质细胞施用锌通过活性氧（ROS）的产生和聚（ADP-核糖）（PAR）的形成激活它们，这通过用25 μ M TPEN（N，N，N '，N'-四（2-吡啶基甲基）乙二胺）或2 μ M BAPTA-AM（1，2-双（2-氨基苯氧基）乙烷-N，N，N '，N'-四乙酸-乙酰氧基甲酯）进行细胞内锌螯合而被抑制。小胶质细胞对Zn-65的摄取具有温度和剂量依赖性，并且可被金属阳离子阻断，但不被L-型钙通道阻断剂硝苯地平和尼莫地平阻断。在小胶质细胞中检测到Zrt-Irt样蛋白（ZIP）1（质膜型锌转运蛋白）的表达，并且镍（ZIP 1的相对敏感的底物/抑制剂）对Zn-65摄取表现出顺式和反式抑制作用。暴露于锌的小胶质细胞的细胞外ATP浓度增加，这是抑制细胞内锌螯合和抑制半通道。在小胶质细胞中检测到几种类型的P2受体的mRNA表达，并且选择性P2 x7受体拮抗剂高碘酸氧化ATP通过NADPH氧化酶和PARP-1减弱锌诱导的小胶质细胞活化。外源性ATP和2 '（3'）-O-（4-benzoyl-benzoyl）ATP也通过ROS的产生和PAR的形成引起小胶质细胞的活化。这些发现表明，ZIP 1介导的锌摄入会诱导ATP释放和P2 X（7）受体的自分泌/旁分泌激活，然后激活小胶质细胞，这表明锌转运蛋白介导的锌摄入是通过NADPH氧化酶和PARP-1途径激活小胶质细胞的触发因素。1途径。(C)2011 Wiley-Liss，Inc.
Previously, we demonstrated that extracellular zinc plays a key role in transient global ischemia-induced microglial activation through sequential activation of NADPH oxidase and poly(ADP-ribose) polymerase (PARP)-1. However, it remains unclear how zinc causes the sequential activation of microglia. Here, we examined whether transporter-mediated zinc uptake is necessary for microglial activation. Administration of zinc to microglia activated them through reactive oxygen species (ROS) generation and poly(ADP-ribose) (PAR) formation, which were suppressed by intracellular zinc chelation with 25 mu M TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine) or 2 mu M BAPTA-AM (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester). The Zn-65 uptake by microglia was temperature- and dose-dependent, and it was blocked by metal cations, but not by L-type calcium channel blockers nifedipine and nimodipine. Expression of Zrt-Irt-like protein (ZIP)1, a plasma membrane-type zinc transporter, was detected in microglia, and nickel, a relatively sensitive substrate/inhibitor of ZIP1, showed cis- and trans-inhibitory effects on the Zn-65 uptake. Exposure of microglia to zinc increased the extracellular ATP concentration, which was suppressed by intracellular zinc chelation and inhibition of hemichannels. mRNA expression of several types of P2 receptors was detected in microglia, and periodate-oxidized ATP, a selective P2x7 receptor antagonist, attenuated the zinc-induced microglial activation via NADPH oxidase and PARP-1. Exogenous ATP and 2'(3')-O-(4-benzoyl-benzoyl) ATP also caused microglial activation through ROS generation and PAR formation. These findings demonstrate that ZIP1-mediated uptake of zinc induces ATP release and autocrine/paracrine activation of P2X(7) receptors, and then activates microglia, suggesting that zinc transporter-mediated uptake of zinc is a trigger for microglial activation via the NADPH oxidase and PARP-1 pathway. (C) 2011 Wiley-Liss, Inc.