IBYME   02675
INSTITUTO DE BIOLOGIA Y MEDICINA EXPERIMENTAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
STUDY OF THE MECHANISMS INVOLVED IN Crisp2-/- SPERM FERTILIZING DEFECTS
Autor/es:
BRUKMAN NG; CUASNICÚ P; CARVAJAL G; DA ROS VG
Lugar:
Buenos Aires
Reunión:
Jornada; XVIII Jornadas Anuales Multidisciplinarias de la Sociedad Argentina de Biología (SAB); 2016
Institución organizadora:
Sociedad Argentina de Biología
Resumen:
Testicular Cysteine-RIch Secretory Protein 2 (CRISP2) is present in sperm and participates in gamete fusion and penetration of both zona pellucida (ZP) and cumulus oophorus during fertilization. In addition, Crisp2-/- sperm exhibit lower percentages of hyperactivation, a vigorous motility required for the penetration of the egg coats, and higher intracellular Ca2+(iCa2+) levels after capacitation, compared to controls. In the present work, we further investigated the mechanisms underlying these Crisp2-/- sperm defects. ZP-intact eggs treated with reduced glutathione to destabilize the ZP prior to their insemination, produced a significant increase in the fertilization levels corresponding to Crisp2-/- sperm, supporting that the lower fertilizing ability of these cells is linked to their lower levels of hyperactivation. We then evaluated iCa2+levels by flow cytometry in mutant sperm incubated in capacitating media containing either an inhibitor of CatSper, the main sperm membrane Ca2+ channel, or lower concentration of CaCl2. Exposure of sperm to any of these conditions produced a reversion of the deregulated iCa2+ of Crisp2-/- cells, indicating that the higher iCa2+ levels of the mutant sperm are dependent on extracellular Ca2+. However, when these treated sperm exhibiting normal iCa2+were subjected to in vitro fertilization, no improvement in the fertilization rates was observed. Together, these observations support the relevance of CRISP2 for the regulation of the complex and fine-tuned Ca2+ regulating system operating in the fertilizing sperm.