From the epididymis to the egg: participation of CRISP proteins in mammalian fertilization

CUASNICÚ PS

Copenhague

Congreso; 11th International Congress of Andrology; 2017

 .Fertilizationis a key process involving a series of coordinated interactions between thegametes. However, the mechanisms underlying this process still remain to beelucidated. Our laboratory has been dedicated to underpin the molecularmechanisms involved in both the acquisition of sperm fertilizing ability duringmaturation and fertilization using CRISP proteins as model molecules.Epididymal protein CRISP1, the first described member of the evolutionarilyconserved CRISP (Cystein-Rich Secretory Protein) family, associates with thesperm surface during maturation. Whereas the loosely bound CRISP1 is releasedduring capacitation having been proposed as a decapacitating factor,substantial evidence obtained using in vitro assays and knockout (KO) modelsshows that the strongly bound population still present in capacitated spermparticipates in different stages of fertilization. These observations can beextended to human as our findings show that the human homologue of CRISP1(hCRISP1) also associates with sperm during maturation and participates infertilization. Recent observations revealed that CRISP1 is also expressed bythe cumulus cells that surround the egg and participates in fertilization bymodulating sperm orientation and hyperactivation through its ability toregulate CatSper, a key sperm Ca(2+) channel essential for male fertility.Together, these observations support the idea that CRISP1 escorts both the maleand female gametes and it is a multifunctional protein playing key roles duringthe fertilization process. We believe these results provide importantinformation for a better mechanistic understanding of both sperm maturation andmammalian fertilization and will contribute to future research on infertilityand contraception.