The extracellular calcium-sensing receptor is expressed in the cumulus-oocyte complex in mammals and modulates oocyte meiotic maturation.
Reproduction
; 138(3): 439-52, 2009 Sep.
Article
en En
| MEDLINE
| ID: mdl-19494043
ABSTRACT
The extracellular calcium-sensing receptor (CASR) plays an important role in cells involved in calcium (Ca2+) homeostasis by directly sensing changes in the extracellular Ca2+ ion concentration. We previously reported the localization and quantitative expression of CASR protein in human oocytes. In this study, we examined the expression and the functional role of CASR during oocyte meiotic maturation in a large mammal animal model, the horse. As in humans, CASR protein was found to be expressed in equine oocytes and cumulus cells. Western-blot analysis revealed a single 130 kDa band in denuded oocytes and a doublet of 130-120 kDa in cumulus cells. CASR labeling was observed by confocal microscopy in cumulus cells and in oocytes on the plasma membrane and within the cytoplasm at all examined stages of meiosis. Functionally, the CASR allosteric effector NPS R-467, in the presence of 2.92 mM external Ca2+, increased oocyte maturation rate in a dose-dependent manner and its stimulatory effect was attenuated by pre-treatment with the CASR antagonist NPS 2390. NPS R-467 had no effect in suboptimal external Ca2+ (0.5 mM), indicating that it requires higher external Ca2+ to promote oocyte maturation. In oocytes treated with NPS R-467, CASR staining increased at the plasmalemma and was reduced in the cytosol. Moreover, NPS R-467 increased the activity of MAPK, also called ERK, in cumulus cells and oocytes. These results provide evidence of a novel signal transduction pathway modulating oocyte meiotic maturation in mammals in addition to the well-known systemic hormones.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Oocitos
/
Receptores Sensibles al Calcio
/
Células del Cúmulo
/
Meiosis
Límite:
Animals
Idioma:
En
Revista:
Reproduction
Asunto de la revista:
MEDICINA REPRODUTIVA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Italia