Alterations in the Protein Kinase C Signaling Activated by a Parthenogenetic Agent in Oocytes From Reproductively Old Mice

作者：Carbone M C; Tatone C^*

来源：Molecular Reproduction and Development, 2009, 76(2): 122-131.

DOI：10.1002/mrd.20923

To investigate the effect of female age on oocyte developmental competence, we focused on protein kinase C (PKC), a major component of the signalling pathway involved in oocyte activation, and put forward the hypothesis that, as it occurs in many organs and tissues, aging affects PKC function in mouse oocytes. Biochemical activity of PKC along with the expression and subcellular distribution of some PKC isoforms were monitored in young and old mouse oocytes parthenogenetically activated by SrCl(2). We found that PKC activity increased reaching a level that was lower in old compared to young oocytes in association with an incomplete translocation of PKC beta 1 to the plasma membrane. Moreover, old oocytes exhibited a reduced expression of PKC beta 1 and PKC alpha at the protein level, without significant effects on the expression of the Ca(2 )-independent PKC delta. Detectable amounts of PKC beta 1 mRNA were observed in young and old oocytes at GV stage with no difference between the two groups of age. When meiotic progression to anaphase II up to first cleavage were analyzed, a delay in meiosis resumption and significantly lower rates of pronuclei formation and first cleavage were observed in old compared to young oocytes. Moreover, we found that, in contrast to SrCl(2), PMA (12-O-tetradecanoyl phorbol-13-acetate), a PKC agonist, was ineffective in activating old oocytes. Present findings provide evidence that aging affects the correct storage and activation of some PKCs, functional components of the machinery involved in oocyte activation, and suggest that these changes may negatively influence the activation competence of old oocytes.

• 出版日期2009-2