Laboratory of Regulatory Biology, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa, 214-8571, Japan.
Laboratory of Proteomics, Department of Life Sciences, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa, 214-8571, Japan.
J Reprod Immunol. 2021 Nov;148:103436. doi: 10.1016/j.jri.2021.103436. Epub 2021 Oct 19.
In both men and women, pathogenic bacteria enter the reproductive tract and cause harmful symptoms. Intrauterine and oviductal inflammation after copulation may have severe effects, such as infertility, implantation failure, oviduct obstruction, and robust life-threatening bacterial infection. Human seminal plasma is considered to be protective against bacterial infection. Among its components, Semenogelin-I/-II proteins are digested to function as bactericidal factors; however, their sequences are not conserved in mammals. Therefore, alternative antibacterial (bactericidal and/or bacteriostatic) systems may exist across mammals. In this study, we examined the antibacterial activity in the seminal plasma of mice lacking a gene cluster encoding Semenogelin-I/-II counterparts. Even in the absence of the majority of seminal proteins, antibacterial activity remained in the seminal plasma. Moreover, a combination of gel chromatography and liquid chromatography coupled with tandem mass spectrometry revealed that the prostate and testis expressed 4 protein as a novel antibacterial (specifically, bacteriostatic) protein, the sequence of which is broadly conserved across mammals. Our results provide the first evidence of a bacteriostatic protein that is widely present in the mammalian seminal plasma.
在男性和女性中，致病菌进入生殖系统并引起有害症状。性交后子宫和输卵管内的炎症可能会产生严重影响，如不孕、着床失败、输卵管阻塞和严重威胁生命的细菌感染。人类精液被认为可以预防细菌感染。在其成分中，精囊蛋白 I/-II 被消化为杀菌因子；然而，它们在哺乳动物中的序列并不保守。因此，哺乳动物之间可能存在替代的抗菌（杀菌和/或抑菌）系统。在这项研究中，我们检查了缺乏编码精囊蛋白 I/-II 对应物的基因簇的小鼠精液中的抗菌活性。即使在缺乏大多数精液蛋白的情况下，精液中仍存在抗菌活性。此外，凝胶色谱和液相色谱与串联质谱联用的组合揭示了前列腺和睾丸表达了 4 种作为新型抗菌（特别是抑菌）蛋白的蛋白，其序列在哺乳动物中广泛保守。我们的结果提供了广泛存在于哺乳动物精液中的抑菌蛋白的首个证据。
