Some characteristics of membrane Cd^<2+> transport in rat thymocytes: An analysis using Fluo-3
Some characteristics of membrane Cd^<2+> transport in rat thymocytes: An analysis using Fluo-3
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大鼠胸腺细胞膜 Cd^2 > 转运的一些特征：使用 Fluo-3 的分析
DOI：
10.1007/s10534-011-9444-3
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发表时间：
2011
期刊：
影响因子：
3.5
通讯作者：
Yasuo Oyama
中科院分区：
文献类型：
--
作者：
Takuya Kawanai;Masahiro Fujinaga;Kazuki Koizumi;Isao Kurotani;Erika Hashimoto;Masaya Satoh;Shoji Imai;Norikazu Miyoshi;Yasuo Oyama
虽然镉诱导淋巴细胞凋亡是镉免疫毒性的共同特征之一，但细胞内镉积累的膜途径尚未完全阐明。为了表征大鼠胸腺细胞膜Cd 2+转运，在细胞内Cd 2+浓度的变化在各种条件下进行了检查，通过使用Fluo-3，一种荧光探针，用于监测细胞内二价金属离子浓度的变化。膜Cd 2+运输的估计由增加Fluo-3荧光诱导浴应用CdCl 2。降低温度强烈抑制CdCl 2对Fluo-3荧光的增强作用，表明代谢过程可能参与了膜Cd 2+的转运。外部酸化（降低pH值）和膜去极化，通过添加KCl衰减的增强，表明电化学驱动力的要求膜Cd 2+运输到细胞。CaCl 2和ZnCl 2的浴施同样降低了增强，表明它们与Cd 2+在膜运输中的竞争。CdCl 2的增强作用在用N-乙基马来酰亚胺处理的细胞中较小，诱导细胞硫醇的化学消耗。结果表明巯基对膜Cd ~（2+）转运有贡献。综上所述，这表明细胞具有温度敏感的膜Cd 2+途径，由Cd 2+的电化学梯度和跨膜电位驱动，具有竞争性结合位点。基于上述特征，大鼠胸腺细胞的膜Cd 2+转运不太可能归因于单一转运系统，尽管其具有与二价阳离子转运蛋白1相似的特征。
Although cadmium-induced apoptosis of lymphocytes is one of common features in the immunotoxicity of cadmium, the membrane pathway for intracellular cadmium accumulation is not fully elucidated. To characterize membrane Cd2+transport of rat thymocytes, the change in intracellular Cd2+concentration under various conditions was examined by the use of Fluo-3, a fluorescent probe for monitoring the change in intracellular concentration of divalent metal cations. The membrane Cd2+transport was estimated by the augmentation of Fluo-3 fluorescence induced by bath application of CdCl2. Lowering temperature strongly suppressed the augmentation of Fluo-3 fluorescence by CdCl2, suggesting that the metabolic process can be involved in membrane Cd2+transport. External acidification (decreasing pH) and membrane depolarization by adding KCl attenuated the augmentation, indicating the requirement of electrochemical driving force for membrane Cd2+transport into the cells. Bath application of CaCl2and ZnCl2equally decreased the augmentation, suggesting their competition with Cd2+at the membrane transport. The augmentation by CdCl2was lesser in the cells treated with N-ethylmaleimide inducing chemical depletion of cellular thiols. The result suggests the contribution of sulfhydryl groups to membrane Cd2+transport. Taken together, it is suggested that the cells possess a temperature-sensitive membrane Cd2+pathway, driven by electrochemical gradient of Cd2+and transmembrane potential, with competitive binding site. Based on the characteristics described above, it is unlikely that the membrane Cd2+transport in rat thymocytes is attributed to a single transport system although it has characteristics that are similar to those of divalent cation transporter 1.