Hydrogen sulfide ameliorates zinc-induced cell death in neuroblastoma SH-SY5Y cells
Hydrogen sulfide ameliorates zinc-induced cell death in neuroblastoma SH-SY5Y cells
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DOI：
10.1080/10715762.2017.1400666
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发表时间：
2017-11
影响因子：
3.3
通讯作者：
Megumi Shimoji;H. Hara;Tetsuro Kamiya;K. Okuda;T. Adachi
中科院分区：
文献类型：
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作者：
Megumi Shimoji;H. Hara;Tetsuro Kamiya;K. Okuda;T. Adachi
摘要以往的研究表明，脑缺血后神经末梢释放过量的锌离子可导致脑损伤。因此，锌离子在脑内的稳态失调被认为与神经毒性密切相关。最近，有报道称硫化氢(H_2S)是一种气体介质，可改善缺血性脑损伤。然而，其作用机制尚不完全清楚。在这项研究中，我们用人神经母细胞瘤SH-SY5Y细胞研究了硫化氢供体硫化钠(NaHS)对锌离子细胞毒性的保护作用。NaHS剂量依赖性地阻止了锌暴露引起的细胞死亡。在锌暴露前用NaHS处理细胞可以起到最有效的保护作用。锌离子诱导细胞内NAD+和ATP的丢失以及线粒体功能障碍，导致与能量产生失败相关的细胞毒性；然而，NaHS阻止了这些由锌离子诱导的事件。此外，NaHS还抑制依赖于锌离子的金属反应转录因子-1的激活和金属硫蛋白基因表达的诱导。用锌离子特异性荧光指示剂FluoZin-3进行的锌离子成像显示，NaHS抑制了锌离子暴露后细胞内锌离子水平的升高。这些结果表明，NaHS抑制了锌离子进入细胞内。以邻氟叠氮基罗丹明(Rho-N3F2)为探针测定NaHS生成的H_2S表明，在锌离子存在下，水溶液中的H_2S含量显著降低。这一发现表明，硫化氢可能直接与锌离子反应，降低细胞外锌离子水平。综上所述，我们得出结论：NaHS通过抑制锌离子进入SH-SY5Y细胞而发挥抗锌细胞毒性的作用。
Abstract Previous reports have demonstrated that excess zinc (Zn2+) released from nerve terminals following cerebral ischemia causes brain injury. Therefore, the disturbance of Zn2+ homeostasis in the brain is thought to be closely linked to neurotoxicity. Recently, hydrogen sulfide (H2S), a gaseous mediator, has been reported to ameliorate ischemic brain injury. However, its mechanism is not fully understood. In this study, we examined whether sodium hydrogen sulfide (NaHS), an H2S donor, protects against Zn2+ cytotoxicity using human neuroblastoma SH-SY5Y cells. NaHS dose-dependently prevented cell death caused by Zn2+ exposure. Treatment of cells with NaHS just before Zn2+ exposure exerted the most potent protection. Zn2+ induced loss of intracellular NAD+ and ATP and mitochondrial dysfunctions, resulting in cytotoxicity associated with failure of energy production; however, NaHS prevented these Zn2+-induced events. In addition, NaHS suppressed Zn2+-dependent activation of metal-responsive transcription factor-1 and induction of metallothionein gene expression. Zn2+ imaging with the Zn2+-specific fluorescent indicator FluoZin-3 revealed that NaHS abolished the elevation of intracellular Zn2+ levels after Zn2+ exposure. These results suggest that entry of Zn2+ into cells was suppressed by NaHS. The measurement of H2S derived from NaHS by o-fluorinated-azido-capped rhodamine (Rho-N3F2), a reaction-based H2S probe, revealed that H2S levels in aqueous solutions were markedly reduced in the presence of Zn2+. This finding suggests the possibility that H2S reacts directly with Zn2+ and decreases extracellular Zn2+ levels. Taken together, we conclude that the protection of NaHS against Zn2+ cytotoxicity is exerted by inhibiting entry of Zn2+ into SH-SY5Ycells.