Haase Hajo, Hebel Silke, Engelhardt Gabriela, Rink Lothar
Institute of Immunology, RWTH Aachen University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany.
Cell Calcium. 2009 Feb;45(2):185-91. doi: 10.1016/j.ceca.2008.09.003. Epub 2008 Nov 1.
Most fluorescent probes for the investigation of calcium signaling also detect zinc ions. Consequently, changes in the intracellular zinc concentration could be mistaken for calcium signals. Thimerosal (TMS) is used as a calcium-mobilizing agent and we analyzed the contribution of zinc ions to the signal observed with fluorescent calcium probes after TMS stimulation. Our findings show that the fluorescent signal in lymphocytes is entirely due to zinc release. Experiments in the T lymphocyte cell line Jurkat and primary human lymphocytes show that TMS and its active metabolite, ethyl mercury, cause an increase in signal intensity with probes designed for the detection of either calcium or zinc ions. The TMS/ethyl mercury-induced signal of the calcium probes Fluo-4 and FURA-2 was completely absent when the zinc chelator TPEN [N,N,N',N'-tetrakis-(2-pyridyl-methyl)ethylenediamine] was added. In contrast, the signal caused by thapsigargin-induced release of calcium from the endoplasmic reticulum was unaffected by TPEN. In light of these observations, zinc may also contribute to calcium signals caused by mercury-containing compounds other than TMS, and a potential involvement of zinc release in the immunomodulatory effects of these substances should be considered.
大多数用于研究钙信号传导的荧光探针也能检测锌离子。因此，细胞内锌浓度的变化可能会被误认为是钙信号。硫柳汞（TMS）用作钙动员剂，我们分析了锌离子对TMS刺激后用荧光钙探针观察到的信号的贡献。我们的研究结果表明，淋巴细胞中的荧光信号完全是由于锌的释放。在T淋巴细胞系Jurkat和原代人淋巴细胞中进行的实验表明，TMS及其活性代谢物乙基汞会导致设计用于检测钙或锌离子的探针的信号强度增加。当添加锌螯合剂TPEN [N,N,N',N'-四（2-吡啶基甲基）乙二胺]时，钙探针Fluo-4和FURA-2的TMS/乙基汞诱导信号完全消失。相比之下，毒胡萝卜素诱导的内质网钙释放所引起的信号不受TPEN的影响。鉴于这些观察结果，锌也可能导致除TMS之外的含汞化合物引起的钙信号，并且应该考虑锌释放可能参与这些物质的免疫调节作用。
