Serine protease inhibitor disrupts sperm motility leading to reduced fertility in female mice†

Abstract

Inhibition of the sperm transport process in the female reproductive tract could lead to infertility. We previously showed that a pan-serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), blocked semen liquefaction in vivo and resulted in a drastic decrease in the number of sperm in the oviduct of female mice. In this study, we used a mouse model to test the efficacy of AEBSF as a reversible contraceptive, a sperm motility inhibitor, and a spermicide. Additionally, this study evaluated the toxicity of AEBSF on mouse vaginal tissues in vivo and human endocervical cells in vitro. We found that female mice treated with AEBSF had significantly less pups born per litter as well as fertilization rates in vivo compared to the vehicle control. We then showed that AEBSF reduced sperm motility and fertilization capability in vitro in a dose-dependent manner. Furthermore, AEBSF also exhibited spermicidal effects. Lastly, AEBSF treatment in female mice for 10 min or 3 consecutive days did not alter vaginal cell viability in vivo, similar to that of the vehicle and non-treated controls. However, AEBSF decreased cell viability of human ectocervical (ECT) cell line in vitro, suggesting that cells in the lower reproductive tract in mice and humans responded differently to AEBSF. In summary, our study showed that AEBSF can be used as a prototype compound for the further development of novel non-hormonal contraceptives for women by targeting sperm transport in the female reproductive tract.

The oocyte cumulus complex regulates mouse sperm migration in the oviduct

“…The entire mount oviduct was used for transcriptomic analysis since there is a potential interaction between the stromal cells and epithelial cells 25 . In Tgfbr2 cKO mice, the upregulation of Has1 and the downregulation of Cemip may prevent sperm migration in the oviduct by increasing hyaluronan levels 37 , and the upregulation of Serpina1e may impair the spermatozoa motility by inhibiting serine proteases 38 . The activation of cell adhesion and NF-kappa B signaling in the oviductal cells of Tgfbr2 cKO mice may impair spermatozoa moving out of the isthmic reservoir 39 .…”

Rhox8 homeobox gene ablation leads to rete testis abnormality and male subfertility in mice

“…And then, motile and non-motile sperm were counted under a dark-field microscope to determine sperm concentration and motility. For more sophisticated and automated analysis, sperm samples were incubated at 37 • C for 15 min and analyzed using computer-assisted sperm analysis (CASA) (SCA CASA system; Fertility Technology Resources, Inc.) following the manufacturer's instructions as previously described [14,15].…”

Male contraceptive development: A medicinal chemistry perspective

“…Pan-serine protease inhibitor, 4-(2aminoethyl)benzenesulfonyl fluoride (AEBSF) shown in Scheme 1, [88] has also been shown to negatively affect sperm motility and viability at millimolar concentrations, in a mouse model of contraception. [89] However, in vitro toxicity testing also demonstrated that at doses of 1 and 5 mM, AEBSF significantly decreased human ectocervical cell (ECT) viability. Consequently, a small fragment-like molecule with a covalent warhead, may interact with many different proteins and both the contraceptive and toxic effects observed may be due to the inhibition of multiple protein targets.…”