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Dual inhibition of protein phosphatase‐1/2A and calpain rescues nerve growth factor‐differentiated PC12 cells from oxygen‐glucose deprivation‐induced cell death
Author(s) -
Nakajima Takayuki,
Wakasa Takashi,
Okuma Yasunobu,
Inanami Osamu,
Nomura Yasuyuki,
Kuwabara Mikinori,
Kawahara Koichi
Publication year - 2005
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.20740
Subject(s) - calpain , creb , protein kinase b , programmed cell death , dephosphorylation , microbiology and biotechnology , apoptosis , phosphorylation , nerve growth factor , phosphatase , biology , chemistry , endocrinology , medicine , biochemistry , receptor , enzyme , transcription factor , gene
In the present study, we examined how the cell survival signaling via cyclic AMP‐responsive element binding protein (CREB) and Akt, and the cell death signaling via cystein proteases, calpain and caspase‐3, are involved in oxygen‐glucose deprivation (OGD) followed by reoxygenation (OGD/reoxygenation)‐induced cell death in nerve growth factor (NGF)‐differentiated PC12 cells. OGD/reoxygenation‐induced cell death was evaluated by LDH release into the culture medium. The level of LDH release was low (9.0% ± 4.1%) immediately after 4 hr of OGD (0 hr of reoxygenation), was significantly increased to 28.6% ± 6.6% at 3 hr of reoxygenation, and remained at similar levels at 6 and 20 hr of reoxygenation, suggesting that reoxygenation at least for 3 hr resulted in the loss of cell membrane integrity. After 4 hr of OGD followed by 3 hr of reoxygenation, dephosphorylation of phosphorylated CREB (pCREB), but not phosphorylated Akt (pAkt), was induced. Under these conditions, calpain‐ but not caspase‐3‐mediated α‐spectrin breakdown product was increased, indicating that OGD/reoxygenation also induced an increase in calpain activity. The restoration of pCREB by protein phosphatase (PP)‐1/2A inhibitors or the inhibition of excessive activation of calpain by calpain inhibitor did not reduce OGD/reoxygenation‐induced LDH release. Cotreatment with PP‐1/2A and calpain inhibitors reduced OGD/reoxygenation‐induced LDH release. The present study suggests that a balance in the phosphorylation and proteolytic signaling is involved in the survival of NGF‐differentiated PC12 cells. © 2005 Wiley‐Liss, Inc.