Hyperactivation is sufficient to release porcine sperm from immobilized oviduct glycans

Abstract

Fertilizing sperm are retained by adhesion to specific glycans on the epithelium of the oviduct forming a reservoir before sperm are released from the reservoir so fertilization can ensue. Capacitated sperm lose affinity for the oviduct epithelium but the components of capacitation that are important for sperm release are uncertain. One important correlate of capacitation is the development of hyperactivated motility. Hyperactivation is characterized by asymmetrical flagellar beating with high beat amplitude. We tested whether the development of full-type asymmetrical motility was sufficient to release sperm from immobilized oviduct glycans. Sperm hyperactivation was induced by four different compounds, a cell-permeable cAMP analog (cBiMPS), CatSper activators (4-aminopyridine and procaine), and an endogenous steroid (progesterone). Using standard analysis (CASA) and direct visualization with high-speed video microscopy, we first confirmed that all four compounds induced hyperactivation. Subsequently, sperm were allowed to bind to immobilized oviduct glycans, and compounds or vehicle controls were added. All compounds caused sperm release from immobilized glycans, demonstrating that hyperactivation was sufficient to release sperm from oviduct cells and immobilized glycans. Pharmacological inhibition of the non-genomic progesterone receptor and CatSper diminished sperm release from oviduct glycans. Inhibition of the proteolytic activities of the ubiquitin–proteasome system (UPS), implicated in the regulation of sperm capacitation, diminished sperm release in response to all hyperactivation inducers. In summary, induction of sperm hyperactivation was sufficient to induce sperm release from immobilized oviduct glycans and release was dependent on CatSper and the UPS.

Sperm Morphometry in Lusitu Pigs and the Motility Characteristics Post-incubation in Non-hyperactivating and Hyperactivating Media: A Comparison with the Large White Genotype

“…There are many different compounds known to induce hyperactivation, including Ca 2+ ionophore A23187, progesterone, and CatSper activators like 4-aminopyridine and procaine (Schmidt and Kamp 2004;Sharif et al 2022). When Ca 2+ ionophore A23187 was used in a previous study (Schmidt and Kamp 2004), approximately 60% of the incubated sperm switched from non-hyperactive to hyperactive motility.…”

Effects of CatSper Stimulation and Inhibition by Progesterone and NNC on Human Sperm

“…Sperm was attached to these specific glycans, forming a reservoir of sperm at the oviduct. Progesterone (80 nM) induced sperm release from oviduct glycans within 30 min [31].…”

The Ubiquitin-Proteasome System Participates in Sperm Surface Subproteome Remodeling during Boar Sperm Capacitation

“…Components of the UPS were shown to participate in capacitation events, such as degradation of protein kinase cAMP-dependent type I regulatory subunit alpha (PRKAR1) and A-kinase anchoring protein 3 (AKAP3) protein [ 39 , 40 , 41 ]; acrosomal remodeling, protein processing, and compartmentalization [ 42 , 43 , 44 ]; hyperactivation [ 41 , 45 ]; and spermadhesin de-aggregation from the sperm surface necessary for sperm detachment from the oviductal epithelium [ 46 ]. In an in vitro and ex vivo capacitation assay, the 26S proteasome is physiologically important for the detachment of spermatozoa from oviductal glycan beads and explants [ 47 , 48 ]. A recent computational study suggested the 26S proteasome to be one of two key regulators of mammalian sperm capacitation [ 49 ].…”