Studies on the participation of neural cadherin in adhesion events during gamete interation

MARIN BRIGGILER, CI; DEL POZO, M; VEIGA, MARíA FLORENCIA; VAZQUEZ LEVIN, M

Plymouth, New Hampshire

Congreso; Gordon Research Conference: Fertilization and activation of development; 2011

Neural cadherin (Ncad) is a transmembrane glycoprotein involved in Ca2+-dependent cellular adhesion and signalling. Evidence from our laboratory has shown that Ncad is expressed in human oocytes and spermatozoa, in regions involved in gamete interaction. The aim of the present work was to evaluate Ncad participation in spermoolemma interaction. The zona pellucida (ZP)-free hamster egg penetration assay (SPA) using human spermatozoa was done in the presence or absence of monoclonal and polyclonal anti Ncad antibodies; in addition, gametes were incubated with specific active and inactive cyclic peptides towards Ncad. Incubation with both monoclonal and polyclonal anti Ncad antibodies (200 and 20 ìg/ml, respectively) resulted in a significant (P<0.01) reduction in the percentaje of penetrated oocytes. Oocyte preincubation with the active peptide (5 mM) but not with the inactive one enhanced human sperm penetration to hamster oocytes (P<0.05); such effect was not observed when oocytes were washed before insemination, suggesting the need of the peptide presence during gamete interaction. No difference in the number of spermatozoa bound to the oolemma, the percentage of motile and acrosome-reacted spermatozoa or the percentage of viable oocytes was found between treated and control conditions. In conjunction, these results support the participation of Ncad in gamete adhesion/fusion events; further studies will help elucidating the molecular mechanisms underlying Ncad role(s) in fertilization.