Epididymal Protein Targets: A Brief History of the Development of Epididymal Protease Inhibitor as a Contraceptive
Epididymal Protein Targets: A Brief History of the Development of Epididymal Protease Inhibitor as a Contraceptive
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DOI：
10.2164/jandrol.110.012781
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发表时间：
2011-11-01
影响因子：
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通讯作者：
Richardson, Richard T.
中科院分区：
文献类型：
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作者：
O'Rand, Michael G.;Widgren, Esther E.;Richardson, Richard T.
位于查佩尔山的北卡罗来纳州大学的生殖生物学实验室开始与人类基因组科学（Rockville，马里兰州）合作，对人类附睾文库进行测序并鉴定附睾特异性基因。在从人类基因组科学获得的第一个克隆中，有一个EPPIN的克隆（官方符号，SPINLW 1）。我们的实验室已经描述了EPPIN（附睾蛋白酶抑制剂）作为人类染色体20 q12 -13.2上的新基因，其编码富含半胱氨酸的蛋白质，该蛋白质含有Kunitz型和WAP型4-二硫键核心共有序列，其特征在于其为蛋白酶抑制剂。EPPIN表达3种mRNA剪接变体，编码睾丸和附睾中发现的2种蛋白质亚型。在2种亚型中，1种是分泌型，1种缺乏分泌信号片段。EPPIN主要是二聚体，尽管经常存在多聚体，并且在其天然形式中，EPPIN在精子表面上与乳转铁蛋白和丛生蛋白复合。在射精过程中，来自精囊的精液凝固蛋白与EPPIN蛋白复合物结合，启动一系列事件，定义EPPIN的功能：调节前列腺特异性抗原（PSA）活性，提供抗菌保护，并结合精液凝固蛋白，从而抑制精子活力。当PSA水解精液凝块中的精液凝固蛋白时，精子获得前向运动能力。使用免疫作为研究抗原功能的工具，我们证明了EPPIN对生育力是必不可少的，因为用重组EPPIN免疫雄性猴子会导致完全但可逆的避孕。为了利用我们对EPPIN功能的理解，我们开发了一种高通量筛选来寻找抑制EPPIN-精液凝固蛋白相互作用和模拟抗EPPIN的化合物，从而抑制精子活力。这些化合物现在正被开发成一种非激素男性避孕药。
The Laboratories for Reproductive Biology at the University of North Carolina at Chapel Hill began collaboration with Human Genome Sciences (Rockville, Maryland) to sequence a human epididymal library and identify epididymal-specific genes. Among the first clones obtained from Human Genome Sciences was a clone for EPPIN (official symbol, SPINLW1). Our laboratory has described EPPIN (epididymal protease inhibitor) as a novel gene on human chromosome 20q12-13.2 that encodes a cysteine-rich protein containing both Kunitz-type and WAP-type 4-disulfide core consensus sequences that characterize it as a protease inhibitor. EPPIN expresses 3 mRNA splice variants that encode 2 protein isoforms found in the testis and epididymis. Of the 2 isoforms, 1 is secreted and 1 lacks a secretory signal piece. EPPIN is predominantly a dimer, although multiples often exist, and in its native form, EPPIN is found on the sperm surface complexed with lactotransferrin and clusterin. During ejaculation, semenogelin from the seminal vesicles is bound to the EPPIN protein complex, initiating a series of events that define EPPIN's function: modulating prostate-specific antigen (PSA) activity, providing antimicrobial protection, and binding semenogelin, thereby inhibiting sperm motility. As PSA hydrolyzes semenogelin in the ejaculate coagulum, spermatozoa gain progressive motility. Using immunization as a tool to study antigen function, we demonstrated that EPPIN is essential for fertility because immunization of male monkeys with recombinant EPPIN results in complete, but reversible, contraception. To exploit our understanding of EPPIN's function, we have developed a high-throughput screen to look for compounds that inhibit EPPIN-semenogelin interaction and mimic anti-EPPIN, inhibiting sperm motility. These compounds are now being developed into a nonhormonal male contraceptive.