Aging
Navigate
Submit an Article
Research Paper|Volume 3, Issue 12|pp 1213—1223

GSTT1 is upregulated by oxidative stress through p38-MK2 signaling pathway in human granulosa cells: possible association with mitochondrial activity

Megumu Ito1, Misa Imai2, Miho Muraki3, Kenji Miyado4, Junwen Qin5, Shigeru Kyuwa3, Yasuhiro Yoshikawa3, Yoshihiko Hosoi6, Hidekazu Saito1, Yuji Takahashi1,4
  • 1Division of Reproductive Medicine, Department of Perinatal Medicine and Maternal Care, National Center for Child Health and Development, Tokyo 157-8535, Japan
  • 2Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA
  • 3Department of Biomedical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
  • 4Department of Reproductive Biology, National Center for Child Health and Development, Tokyo 157-8535, Japan
  • 5Institute of Reproductive Immunology and Key Laboratory for Regenerative Medicine, Ministry of Education, Jinan University, Guangzhou 510632, China
  • 6Division of Biological Science, Graduate School of Biology-Oriented Science and Technology, Kinki University, Wakayama, 649-6493 Japan
Received: December 26, 2011Accepted: December 27, 2011Published: December 28, 2011
https://doi.org/10.18632/aging.100418

Copyright: © 2011 Ito et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

We previously reported that GSTT1 was upregulated in human granulosa cells during aging and that activation and localization of p38 MAPK was changed in parallel. Although oxidative stress is responsible for these changes, the age-associated expression of GSTT1 regulated by MAPKs and the role of GSTT1 in aged granulosa cells remain unclear. Therefore, we examined the relationship between the expression of GSTT1 and MAPK signaling pathways using human granulosa-like KGN cells stimulated with H2O2 in the presence or absence of various MAPK inhibitors. Interestingly, H2O2-induced GSTT1 was only inhibited by a p38 inhibitor. An inhibitor of MK2, a downstream regulator of p38, also diminished H2O2-induced GSTT1 upregulation. Notably, both p38 and MK2 were significantly inactivated in cells carrying an shRNA construct of GSTT1 (ΔGSTT1 cells), suggesting that the p38-MK2 pathway is essential for age-associated upregulation of GSTT1. The relevance of GSTT1 in mitochondrial activity was then determined. ΔGSTT1 cells displayed enhanced polarization of mitochondrial membrane potential without increasing the apoptosis, suggesting that the age-associated upregulation of GSTT1 may influence the mitochondrial activity of granulosa cells.

Collectively, it appears that the age-associated expression of GSTT1 is induced through the p38 signaling pathway and GSTT1 influences homeostatic activities in granulosa cells.