Effects of antioxidants on calcium influx through TRPM2 channels in transfected cells activated by hydrogen peroxide
Effects of antioxidants on calcium influx through TRPM2 channels in transfected cells activated by hydrogen peroxide
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DOI：
10.1016/j.jns.2008.03.003
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发表时间：
2008-07-15
影响因子：
4.4
通讯作者：
Lueckhoff, Andreas
中科院分区：
文献类型：
--
作者：
Naziroglu, Mustafa;Lueckhoff, Andreas
类褪黑激素瞬时受体电位 2 (TRPM2) 通道是一种氧化还原敏感的 Ca(2+) 可渗透阳离子通道，可通过与通道的酶 Nudix 结构域结合的 H(2)O(2) 进行门控。由于导致 TRPM2 响应 H(2)O(2) 的作用机制尚不清楚，我们在转染的中国仓鼠卵巢 (CHO) 细胞中检查了各种抗氧化剂对 H(2)O(2) 诱导的 TRPM2 阳离子通道电流的影响。CHO 细胞用编码 TRPM2 的 cDNA 转染。使用传统的全细胞膜片钳技术测量膜电流。细胞内溶液含有乙二胺四乙酸（EDTA）作为Ca（2+）和重金属离子的螯合剂，而不是乙二醇四乙酸（EGTA）。此外，我们选择的细胞内Ca(2+)浓度计算在1μM范围内。H(2)O(2)(10mM)在细胞外添加到浴室中。在这些条件下，我们能够诱发与 H(2)O(2) 一致的 TRPM2 电流。接下来我们测试了在细胞外或细胞内应用维生素 C 和 E 或谷胱甘肽 (GSH) 是否会阻止或减弱 H(2)O(2) 对 TRPM2 电流的诱导。出乎意料的是，施用这些抗氧化剂并没有抑制H(2)O(2)对TRPM2的激活。总之，TRPM2通道被H(2)O(2)组成型激活，尽管我们没有检测到抗氧化剂的任何抑制作用。对 CHO 细胞中 H(2)O(2) 诱导的 TRPM2 阳离子通道电流的影响。 (c) 2008 Elsevier B.V. 保留所有权利。
Melastatin-like transient receptor potential 2 (TRPM2) channel is a redox sensitive Ca(2+)-permeable cation channel that can be gated by H(2)O(2) binding to the channel's enzymatic Nudix domain. Since the mechanisms that lead to TRPM2 action in response to H(2)O(2) are not understood, we examined the effects of various antioxidants on H(2)O(2)-induced TRPM2 cation channel cur-rents in transfected Chinese hamster ovary (CHO) cells.The CHO cells were transfected with cDNA coding for TRPM2. Membrane currents were measured with the conventional whole cell patch-clamp technique. The intracellular solution contained ethylenediamine tetraacetic acid (EDTA) as a chelator for Ca(2+) and heavy metal ions instead of ethylene glycol tetraacetic acid (EGTA). Moreover, we chose an intracellular Ca(2+) concentration calculated to be in the range of 1 mu M. H(2)O(2) (10 mM) was added extracellularly to the bath chamber. With these conditions, we were able to evoke TRPM2 currents consistently with H(2)O(2). We next tested whether vitamins C and E or glutathione (GSH) would prevent or attenuate the induction of TRPM2 currents by H(2)O(2) when applied extracellularly or intracellularly. Unexpectedly, administration of these antioxidants did not inhibit activation of TRPM2 by H(2)O(2).In conclusion, TRPM2 channels were constitutively activated by H(2)O(2) although we could not detect any inhibitory effect of the antioxidants. on H(2)O(2)-induced TRPM2 cation channel currents in CHO cells. (c) 2008 Elsevier B.V. All rights reserved.