Antimicrobial activity of human EPPIN, an androgen-regulated, sperm-bound protein with a whey acidic protein motif
Antimicrobial activity of human EPPIN, an androgen-regulated, sperm-bound protein with a whey acidic protein motif
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DOI：
10.1095/biolreprod.104.031567
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发表时间：
2004-11-01
影响因子：
3.6
通讯作者：
Hall, SH
中科院分区：
文献类型：
--
作者：
Yenugu, S;Richardson, RT;Hall, SH
附睾精子结合蛋白除了在精子成熟中的作用外，在生殖道免疫中的作用也得到了广泛的认识。精子在通过附睾的过程中获得前向运动能力和可复性能力，在附睾中获得属于不同类别的各种蛋白质。以前，我们证明，EPPIN（附睾蛋白酶抑制剂），雄激素调节，精子结合蛋白含有蛋白酶抑制基序，是在睾丸和附睾特异性表达。本实验研究了EPPIN对大肠杆菌的抗菌活性及其作用机制。EPPIN具有剂量和时间依赖性的抗菌活性，对盐相对不敏感。然而，EPPIN在其半胱氨酸的还原和烷基化后完全失去其抗菌活性，表明二硫键对其活性的重要性。EPPIN可使E. coli中，这与其诱导大肠杆菌显著形态学改变的能力相一致。大肠杆菌膜，如扫描电子显微镜所示。在大鼠红细胞溶血试验中，EPPIN没有引起真核细胞膜的破坏。本研究结果表明，EPPIN在人附睾先天免疫系统中具有一定的作用。
The role of epididymal sperm-binding proteins in reproductive tract immunity is now well recognized in addition to their role in sperm maturation. Spermatozoa acquire forward motility and fertilizing ability during their passage through the epididymis, where they acquire a wide variety of proteins belonging to different classes. Previously, we demonstrated that EPPIN (epididymal protease inhibitor), an androgen-regulated, sperm-binding protein containing protease-inhibitory motifs, is expressed specifically in the testis and epididymis. In the present study, we investigated the antibacterial activity of EPPIN against Escherichia coli and the mechanism of antimicrobial action. EPPIN exhibited dose- and time-dependent antibacterial activity that was relatively insensitive to salt. However, EPPIN lost its antibacterial activity completely on reduction and alkylation of its cysteines, indicating the importance of disulfide bonds for its activity. EPPIN permeabilized the outer and inner membranes of E. coli, which is consistent with its ability to induce striking morphological alterations of E. coli membranes as shown by scanning electron microscopy. EPPIN did not cause disruption of eukaryotic membranes in the rat erythrocyte hemolytic assay. The present results indicate that EPPIN has a role in the innate immune system of human epididymis.