Role of the Na+/Ca2+ exchanger in calcium homeostasis and human sperm motility regulation
Role of the Na+/Ca2+ exchanger in calcium homeostasis and human sperm motility regulation
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DOI：
10.1002/cm.20108
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发表时间：
2006-02-01
影响因子：
--
通讯作者：
Márián, T
中科院分区：
文献类型：
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作者：
Krasznai, Z;Krasznai, ZT;Márián, T
许多细胞功能，如鞭毛跳动、游动速度、顶体反应等，都是由Ca2+穿过细胞膜的内流触发的。为了适当的生理功能，活动的人类精子将细胞内游离钙浓度（[Ca2+](i)）维持在亚微摩尔水平。本研究的目的是确定Na+/Ca2+交换器（NCX）在维持[Ca2+](i)在人类精子中的作用。在含有>= 1 μ M Ca2+的细胞外培养基中维持的精子表现出与对照组相似的运动性。除了前面描述的几种钙转运机制外，我们提供的证据表明NCX在维持[Ca2+]中起着至关重要的作用(i)。三种化学上不相关的NCX抑制剂（bepridil， DCB（3',4'-盐酸二氯苯甲胺）和KB-87943）均以剂量和孵育时间依赖的方式阻断人类精子活力。bepridil、DCB和KB-87943的IC50值分别为16.2、9.8和5.3 μ M。用上述阻滞剂治疗导致[Ca2+](i)升高和[Na+](i)降低。储存操作钙通道（SOCC）抑制剂SKF 96365也能抑制精子运动（IC50 = 2.44 μ M）。通过流式细胞术、共聚焦激光扫描显微镜和免疫印迹技术证实了NCX抗原在人精子中的存在。人类精子的钙稳态是由几种转运蛋白维持的，其中SOCC和NCX可能起主要作用。
A number of cell functions, such as flagellar beating, swimming velocity, acrosome reaction, etc., are triggered by a Ca2+ influx across the cell membrane. For appropriate physiological functions, the motile human sperm maintains the intracellular free calcium concentration ([Ca2+](i)) at a Submicromolar level. The objective of this study was to determine the role of the Na+/Ca2+ exchanger (NCX) in the maintenance of [Ca2+](i) in human spermatozoa. Spermatozoa maintained in extracellular medium containing >= 1 mu M Ca2+ exhibited motility similar to that of the control. In addition to several calcium transport mechanisms described earlier, we provide evidence that the NCX plays a crucial role in the maintenance of [Ca2+](i). Three chemically unrelated inhibitors of the NCX (bepridil, DCB (3',4'-dichlorobenzamil hydrochloride), and KB-87943) all blocked human sperm motility in a dose and incubation time dependent manner. The IC50 values for bepridil, DCB, and KB-87943 were 16.2, 9.8, and 5.3 mu M, respectively. The treatment with the above-mentioned blockers resulted in an elevated [Ca2+](i) and a decreased [Na+](i). The store-operated calcium channel (SOCC) inhibitor SKF 96365 also blocked the sperm motility (IC50 = 2.44 mu M). The presence of the NCX antigen in the human spermatozoa was proven by flow cytometry, confocal laser scanning microscopy, and immunoblotting techniques. Calcium homeostasis of human spermatozoa is maintained by several transport proteins among which the SOCC and the NCX may play a major role.