Loss of Calcium in Human Spermatozoa via EPPIN, the Semenogelin Receptor
Loss of Calcium in Human Spermatozoa via EPPIN, the Semenogelin Receptor
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DOI：
10.1095/biolreprod.111.094227
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发表时间：
2012-02-01
影响因子：
3.6
通讯作者：
Widgren, Esther E.
中科院分区：
文献类型：
--
作者：
O'Rand, Michael G.;Widgren, Esther E.
开发一种新的男性避孕药需要从动物模型过渡到人类模型，并了解靶点抑制人类精子生育力的机制。我们现在报告，精液凝固蛋白（SEMG 1）和抗EPPIN抗体的21个氨基酸的C端上的一个定义的目标网站的EPPIN引起细胞内钙的损失，通过Fluo-4测量。细胞内钙离子的丢失解释了我们先前的观察结果，即当精子用SEMG 1或抗EPPIN抗体处理时，最初的前向运动力丧失，最终运动力完全丧失。噻吗替林可以挽救SEMG 1对运动性的影响，这意味着钙的内部储存没有耗尽。此外，精子的SEMG 1处理降低了细胞内pH，并且可以通过氯化铵来拯救运动性。本研究的结果表明，EPPIN通过结合SEMG 1控制精液中的精子活力，导致钙的损失，最有可能是通过干扰内部pH值和抑制摄取机制。然而，EPPIN-SEMG 1复合物对内部钙水平发挥作用的确切步骤尚不清楚。抗EPPIN抗体可以替代SEMG 1，因此，模拟抗EPPIN结合的小分子量化合物应该能够替代SEMG 1，为非抗体、非激素男性避孕药提供基础。
The development of a new male contraceptive requires a transition from animal model to human and an understanding of the mechanisms involved in the target's inhibition of human spermatozoan fertility. We now report that semenogelin (SEMG1) and anti-EPPIN antibodies to a defined target site of 21 amino acids on the C terminal of EPPIN cause the loss of intracellular calcium, as measured by Fluo-4. The loss of intracellular calcium explains our previous observations of an initial loss of progressive motility and eventually the complete loss of motility when spermatozoa are treated with SEMG1 or anti-EPPIN antibodies. Thimerosal can rescue the effects of SEMG1 on motility, implying that internal stores of calcium are not depleted. Additionally, SEMG1 treatment of spermatozoa decreases the intracellular pH, and motility can be rescued by ammonium chloride. The results of this study demonstrate that EPPIN controls sperm motility in the ejaculate by binding SEMG1, resulting in the loss of calcium, most likely through a disturbance of internal pH and an inhibition of uptake mechanisms. However, the exact steps through which the EPPIN-SEMG1 complex exerts its effect on internal calcium levels are unknown. Anti-EPPIN antibodies can substitute for SEMG1, and, therefore, small-molecular weight compounds that mimic anti-EPPIN binding should be able to substitute for SEMG1, providing the basis for a nonantibody, nonhormonal male contraceptive.