Involvement of cAMP efflux, through MRP4 transporter, in the acquisition of fertilizing ability of mouse spermatozoa

RAQUEL LOTTERO-LECONTE, ZOILO J VERNAZ, SILVINA PEREZ MARTINEZ; MARÍA GRACIA GERVASI; NICOLÁS DI SIERVI, CARLOS DAVIO; LUQUE GUILLERMINA M, BUFFONE M ; CARLOS AGUSTÍN ISIDRO ALONSO

Quebec

Simposio; Symposium de la Réseau Québecois en Reproduction; 2019

Involvement of cAMP efflux, through MRP4 transporter, in the acquisition of fertilizing ability of mouse spermatozoaCarlos Agustín Isidro Alonso1, Raquel Lottero-Leconte2, Luque Guillermina M3,Zoilo J Vernaz2, Nicolás Di Siervi4, María Gracia Gervasi5, Mariano G Buffone3,Carlos Davio4, Silvina Perez Martinez12e Symposium du RQR ? 12th RQR Symposium- Pagina 31.-To fertilize the oocyte mammalian spermatozoa must undergo a series of biochemicalchanges, altogether known as capacitation. Levels of cAMP are tightly regulated duringthis process by the ratio between its synthesis and degradation. However, in other celltypes, cAMP efflux through the Multidrug Resistance Protein 4 (ABCC4/MRP4)contributes to modulate the availability of this nucleotide and provides cAMP to theextracellular space. We previously demonstrated that bovine spermatozoa possessfunctional MRP4 and the pharmacological blockade of MRP4 inhibits capacitationrelated events, whereas addition of extracellular cAMP (ecAMP) restores capacitation.In the present work we aim to further describe the role of MRP4 in mammalian spermphysiology, hence we investigated its participation in mouse sperm capacitation.Results showed that mouse spermatozoa possess MRP4 and incubation with MK571(50 μM), an MRP4 inhibitor, resulted in accumulation of intracellular cAMP and a decrease in ecAMP. Inhibition of MRP4 also produced a decrease in tyrosine phosphorylation, sperm motility, hyperactivation and in vitro fertilization, and addition ofecAMP (1 nM) failed to restore capacitation. However, unlike bovine, mouse spermatozoa showed increased Ca2+ levels with the MRP4 inhibitor. Furthermore, the absence of Ca2+ salts in the medium prevented the loss of motility induced by MK571.A similar response was observed in spermatozoa from CatSper KO mouse, supporting the association between MRP4 and Ca2+ homeostasis in this species. Altogether, our results suggest that MRP4 plays a critical role in mammalian sperm capacitation, although the signaling pathways associated to this transporter differbetween murine and bovine spermatozoa.