Abstract
We examined the possibility that p38 mitogen-activated protein kinase and caspase-3 would be activated for execution of apoptosis and excitotoxicity, the two major types of neuronal death underlying hypoxic- ischemic and neurodegenerative diseases. Mouse cortical cell cultures underwent widespread neuronal apoptosis 24 h following exposure to 10-30 nM calyculin A, a selective inhibitor of Ser/Thr phosphatase I and IIA. Activity of p38 was increased 2-4 h following exposure to 30 nM calyculin A. Addition of 3-10 μM PD169316, a selective p38 inhibitor, partially attenuated calyculin A neurotoxicity. Activity of caspase-3-like proteases was increased in cortical cell cultures exposed to 30 nM calyculin A for 8-16 h as shown by cleavage of DEVD-p-nitroanilide and phosphorylated tau. Proteolysis of tau was completely blocked by addition of 100 μM N-benzyloxycarbonyl-Val-Ala- Asp-fluoromethyl ketone (z-VAD-fmk), a broad-spectrum inhibitor of caspases, but incompletely by 10 μM PD169316. Calyculin A neurotoxicity was partially sensitive to 100 μM z-VAD-fmk. Cotreatment with 10 μM PD169316 and 100 μM z-VAD-fmk showed additive neuroprotection against calyculin A. Neither PD169316 nor z-VAD-fmk showed a beneficial effect against excitotoxic neuronal necrosis induced by exposure to 20 μM NMDA. Thus, caspase-3-like proteases and p38 likely contribute to calyculin A-induced neuronal apoptosis but not NMDA-induced neuronal necrosis.
Original language | English |
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Pages (from-to) | 2455-2461 |
Number of pages | 7 |
Journal | Journal of Neurochemistry |
Volume | 74 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2000 |
All Science Journal Classification (ASJC) codes
- Biochemistry
- Cellular and Molecular Neuroscience