The epididymis-specific antimicrobial peptide beta-defensin 15 is required for sperm motility and male fertility in the rat

Recently, the achievements made by Prof. Yonglian Zhang’s group were published on Cellular and Molecular Life Sciences. The scientists find that the epididymis-specific antimicrobial peptide β-defensin 15 (Defb15) is required for sperm motility and male fertility in the rat.

 

Spermatozoa acquire forward motility and fertilizing capacity during their transit through the epididymis. The maturation process involves modifications of the sperm surface by different proteins that are secreted by a series of specialized regions in the epididymal epithelium. In this study, the researchers find that the rat epididymis-specific Defb15 exhibits an androgen-dependent expression pattern, which can bind to the acrosomal region of caput sperm. Coculture of caput spermatozoa with Defb15 antibody in vitro resulted in a significant decline in sperm motility. Moreover, the total and progressive motility of the spermatozoa dramatically decreased in rats when Defb15 was downregulated by lentivirus-mediated RNAi in vivo. Remarkably, knock down of Defb15 led to a reduction in fertility and embryonic development failure. In addition, the recombinant Defb15 showed antimicrobial activity in a dose-dependent fashion. These results indicate that Defb15 plays a dual role in both sperm maturation and pathogen defense in rat epididymis.

 

This research was supported by the Ministry of Science and Technology, National Natural Science Foundation of China, Shanghai Municipal Commission for Science and Technology, and Chinese Academy of Sciences.