Patterns of [Ca2+]i mobilization and cell response in human spermatozoa exposed to progesterone
Patterns of [Ca2+]i mobilization and cell response in human spermatozoa exposed to progesterone
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DOI：
10.1016/j.ydbio.2006.09.040
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发表时间：
2007-02-01
影响因子：
2.7
通讯作者：
Publicover, S. J.
中科院分区：
文献类型：
--
作者：
Bedu-Addo, K.;Barratt, C. L. R.;Publicover, S. J.
用黄体酮（卵丘的产物，因此在体内受精之前精子会遇到）刺激的人类精子显然会动员 Ca2+，并根据类固醇的呈现方式做出非常不同的反应。孕酮浓度梯度 (0-3 μM) 诱导 [Ca2+](i) 振荡（重复储存动员），从而改变鞭毛跳动，而微摩尔孕酮的推注应用会导致单个大瞬态（导致顶体反应），这显然依赖于 Ca2+ 流入。我们研究了暴露于 3 μM 黄体酮的人类精子的 Ca2+ 动员和功能反应。在 0 Ca2+ 培养基 (2 mM EGTA) 中孵育 4 分钟消除了对孕酮的 [Ca2+](i) 反应，但在名义上不含 Ca2+ 的培养基（未添加 Ca2+；0 EGTA）中，出现了较小且缓慢的反应。单细胞成像显示名义上不含 Ca2+ 的培养基具有类似的效果，并且即使在存在 EGTA 的情况下，大约 5% 的细胞也会产生小的瞬变。当细胞暴露于含有 EGTA 的盐水（5 分钟），然后在刺激前返回到名义上不含 Ca2+ 的培养基中时，与未接受 EGTA 预处理的细胞相比，[Ca2+](i) 瞬变大大延迟（约 50 秒），上升时间加倍。我们得出的结论是，储存的 Ca2+ 的动员对孕酮诱导的 [Ca2+](i) 瞬态贡献了一个“缓慢”的成分，并且在 EGTA 缓冲盐水中孵育能够快速耗尽该储存。对 3 μM 黄体酮诱导的鞭毛活性的分析表明，在 > 80% 的名义上不含 Ca2+ 的培养基中的细胞中，存在与 [Ca2+](i) 瞬态相关的效应（改良的跳动）。在经过 5 分钟 EGTA 预处理的细胞中，这种情况大大减少。存储介导的瞬态显示出与孕酮诱导的 [Ca2+](i) 振荡相似的药理学敏感性（与 SPCA 存储的填充一致），表明微摩尔孕酮诱导的瞬态是产生 Ca2+ 振荡的同一存储的“单次”激活。 (c) 2006 Elsevier Inc. 保留所有权利。
Human spermatozoa stimulated with progesterone (a product of the cumulus and thus encountered by sperm prior to fertilization in vivo) apparently mobilize Ca2+ and respond very differently according to the way in which the steroid is presented. A progesterone concentration ramp (0-3 mu M) induces [Ca2+](i) oscillations (repetitive store mobilization) which modify flagellar beating, whereas bolus application of micromolar progesterone causes a single large transient (causing acrosome reaction) which is apparently dependent upon Ca2+ influx. We have investigated Ca2+-mobilization and functional responses in human sperm exposed to 3 mu M progesterone. The [Ca2+](i) response to progesterone was abolished by 4 min incubation in 0 Ca2+ medium (2 mM EGTA) but in nominally Ca2+-free medium (no added Ca2+; 0 EGTA) a smaller, slow response occurred. Single cell imaging showed a similar effect of nominally Ca2+-free medium and approximate to 5% of cells generated a small transient even in the presence of EGTA. When cells were exposed to EGTA-containing saline (5 min) and then returned to nominally Ca2+-free medium before stimulation, the [Ca2+](i) transient was greatly delayed (approximate to 50 s) and rise time was doubled in comparison to cells not subjected to EGTA pretreatment. We conclude that mobilization of stored Ca2+ contributes a 'slow' component to the progesterone-induced [Ca2+](i) transient and that incubation in EGTA-buffered saline is able rapidly to deplete this store. Analysis of flagellar activity induced by 3 mu M progesterone showed an effect (modified beating) associated with the [Ca2+](i) transient, in > 80% of cells bathed in nominally Ca2+-free medium. This was reduced greatly in cells subjected to 5 min EGTA pre-treatment. The store-mediated transient showed a pharmacological sensitivity similar to that of progesterone-induced [Ca2+](i) oscillations (consistent with filling of the store by an SPCA) suggesting that the transient induced by micromolar progesterone is a 'single shot' activation of the same store that generates Ca2+ oscillations. (c) 2006 Elsevier Inc. All rights reserved.