Su Linlin, Zhang Yufei, Cheng Yan C, Lee Will M, Ye Keping, Hu Dahai
Department of Burns and Cutaneous Surgery, Xijing Hospital, the Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
Heilongjiang Key Laboratory of Anti-fibrosis Biotherapy, Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, China.
Sci Rep. 2015 Nov 5;5:16271. doi: 10.1038/srep16271.
Spermiation and BTB restructuring, two critical cellular events that occur across seminiferous epithelium in mammalian testis during spermatogenesis, are tightly coordinated by biologically active peptides released from laminin chains. Our earlier study reported that F5-peptide, synthesized based on a stretch of 50 amino acids within laminin-γ3 domain IV, could reversibly induce the impairment of spermatogenesis, disruption of BTB integrity, and germ cell loss, and thus is a promising male contraceptive. However, how F5-peptide when administered intratesticularly enters seminiferous tubules and exerts effects beyond BTB is currently unknown. Here we demonstrated that Slc15a1, a peptide transporter also known as Pept1, was predominantly present in peritubular myoid cells, interstitial Leydig cells, vascular endothelial cells and germ cells, while absent in Sertoli cells or BTB site. The steady-state protein level of Slc15a1 in adult rat testis was not affected by F5-peptide treatment. Knockdown of Slc15a1 by in vivo RNAi in rat testis was shown to prevent F5-peptide induced disruptive effects on spermatogenesis. This study suggests that Slc15a1 is involved in the transport of synthetic F5-peptide into seminiferous epithelium, and thus Slc15a1 is a novel target in testis that could be genetically modified to improve the bioavailability of F5-peptide as a prospective male contraceptive.
精子释放和血睾屏障重组是哺乳动物睾丸生精过程中发生在生精上皮的两个关键细胞事件，它们由层粘连蛋白链释放的生物活性肽紧密协调。我们早期的研究报告称，基于层粘连蛋白γ3结构域IV内一段50个氨基酸合成的F5肽，可可逆地诱导生精障碍、破坏血睾屏障完整性并导致生殖细胞丢失，因此是一种有前景的男性避孕药。然而，目前尚不清楚睾丸内注射F5肽后如何进入生精小管并在血睾屏障之外发挥作用。在此我们证明，肽转运体Slc15a1（也称为Pept1）主要存在于睾丸肌样细胞、间质Leydig细胞、血管内皮细胞和生殖细胞中，而在支持细胞或血睾屏障部位不存在。成年大鼠睾丸中Slc15a1的稳态蛋白水平不受F5肽处理的影响。在大鼠睾丸中通过体内RNA干扰敲低Slc15a1可防止F5肽对生精的破坏作用。本研究表明，Slc15a1参与将合成的F5肽转运到生精上皮中，因此Slc15a1是睾丸中的一个新靶点，可通过基因改造来提高F5肽作为一种潜在男性避孕药的生物利用度。
