Physiological basis of contraceptive function of a GSK3α-selective inhibitor, manifested during epididymal sperm maturation

ABSTRACT: Glycogen synthase kinase 3 alpha (GSK3α) has emerged as a prospective target to develop male contraceptives. The GSK3α paralog is highly conserved and present in the sperm of placental mammals. Global or testis-specific loss of GSK3α, but not GSK3β, results in male infertility. A preliminary study showed that in vivo administration of the GSK3α-specific inhibitor, BRD0705, to heterozygous (Gsk3a +/-) male mice results in reversible male infertility. Previous studies demonstrated that the GSK3α-selective inhibitor BRD0705 induces reversible infertility in heterozygous mice. Here, we show that the treatment of BRD0705 in wild-type male mice also results in equally effective male sterility. Here, we show that BRD0705 induces similar infertility in wild-type male mice. Superovulation in female mice does not alter fertility outcomes when mated with BRD0705-treated males. Further, no evidence of fetal resorption was observed in these females. Sperm numbers in treated mice were not altered; however, morphological defects appeared during their passage through the epididymis. The reversibility of BRD0705 treatment was also established by performing a 3-month in vivo fertilisation study in male mice after cessation of BRD0705 treatment. The GSK3α inhibitor affected pathways related to the enzyme's catalytic activity in epididymal sperm. Phospho-proteome analysis of sperm from inhibitor-treated mice showed that phosphorylation of over 50 proteins involved in motility, metabolism and fertility, among others, was Phosphoproteome analysis of sperm from inhibitor-treated mice showed that phosphorylation of over 50 proteins involved in motility, metabolism, and fertility, among others, was significantly altered. Among the highly hypophosphorylated proteins, four are likely substrates of GSK3 (viz., AKAP4, NT5C1B, SPATA18, and TRA2B), as they show reduced phosphorylation within the consensus GSK3 phosphorylation sequence. Analysis of the seminiferous tubules of BRD0705-treated mice showed normal spermatogenesis, suggesting that the drug did not affect developing spermatogenic cells. However, in vitro exposure of post-meiotic germ cells demonstrated their susceptibility to this inhibitor. These findings support GSK3α inhibition via BRD0705 as a non-hormonal, on-demand, and reversible male contraceptive strategy.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Testis, Sperm

DISEASE(S): Male Infertility

SUBMITTER: Belinda Willard  

LAB HEAD: Srinivasan Vijayaraghavan, PhD

PROVIDER: PXD079474 | Pride | 2026-07-29

REPOSITORIES: Pride