The role of brain-derived neurotrophic factor in mouse oocyte maturation in vitro involves activation of protein kinase B

Zhang, L.; Liang, Y.; Liu, Y.; Xiong, C.-L.

doi:10.1016/j.theriogenology.2010.01.009

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Volume 73, Issue 8 , Pages 1096-1103, May 2010

The role of brain-derived neurotrophic factor in mouse oocyte maturation in vitro involves activation of protein kinase B

L. Zhang
- Family Planning Research Institute and Centre for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
Y. Liang
- Department of Social Medicine, Public Health School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
Y. Liu
- Family Planning Research Institute and Centre for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
C.-L. Xiong
- Family Planning Research Institute and Centre for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
- Corresponding author. Tel.: +86 27 83692651; fax: +86 27 83692651.

Received 13 July 2009; received in revised form 24 December 2009; accepted 9 January 2010. published online 22 February 2010.

Abstract

Brain-derived neurotrophic factor (BDNF) can promote developmental competence in mammalian oocytes during in vitro maturation, but the signal transduction pathways are not clear. In this study, we investigated (using western blots) the effects of BDNF on the phosphorylation of protein kinase B (PKB) and mitogen-activated protein kinase (MAPK) in mouse oocytes and cumulus cells cultured in vitro. Treatment with BDNF enhanced phosphorylation of PKB in oocytes at 2h (P=0.0006) and 3h (P<0.0001) of in vitro maturation, compared with control oocytes. However, the pan-specific tyrosine kinase (Trk) inhibitor K252a together with BDNF completely inhibited phosphorylation of PKB in the oocytes. Furthermore, BDNF increased phosphorylation of MAPK in oocytes at 16h of in vitro maturation (P=0.0041), but K252a together with BDNF did not reduce phosphorylation of MAPK in the oocytes. For cumulus cells, BDNF significantly prolonged the phosphorylation of PKB and MAPK and increased the total amounts of PKB and MAPK proteins after 16h of in vitro maturation. However, BDNF did not affect apoptosis of the cumulus cells during oocyte maturation in vitro. In conclusion, the PKB pathway is likely to be one signaling cascade activated by BDNF in combination with the TrkB receptor, whereas the MAPK pathway is not involved. These findings may have relevance for BDNF-induced promotion of developmental capacity of in vitro-matured oocytes.