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Okadaic acid induced cyclin B1 expression and mitotic catastrophe in rat cortex
Bo Chen1, Min Cheng, Dao-Jun Hong
1National Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai, PR China.
Neuroscience Letters
|August 22, 2006
Summary
Okadaic acid (OA) forces adult neurons into cell division, causing mitotic catastrophe and potentially contributing to Alzheimer's disease pathogenesis. This study demonstrates OA's role in neuronal cell cycle re-entry and subsequent cell death.
Area of Science:
- Neuroscience
- Cell Biology
- Pathology
Background:
- Aberrant cell cycle re-entry in neurons is implicated in Alzheimer's disease (AD).
- The mechanisms driving neuronal cell cycle re-entry and subsequent cell death remain unclear.
- Okadaic acid (OA), a phosphatase inhibitor, induces AD-like changes and mitotic events in neuroblastoma cells.
Purpose of the Study:
- To investigate the in vivo effects of OA on neuronal cell cycle progression and mitotic catastrophe.
- To determine if OA can induce cell cycle re-entry and death in differentiated neurons.
Main Methods:
- Intracortical injection of OA into adult rat brains.
- Immunohistochemistry for cyclin B1 and phosphorylated tau.
- Cell morphology analysis using toluidine blue, Giemsa dye, and propidium iodide staining.
- Detection of neuron-specific enolase.
Main Results:
- OA injection significantly increased cyclin B1 expression and tau phosphorylation in adult neurons.
- OA induced mitotic and mitotic catastrophe-like morphological changes in some neurons.
- Cyclin B1 expression correlated with mitotic catastrophe, suggesting its role in G2 to M phase transition.
- Neuron-specific enolase confirmed that affected cells were neurons.
Conclusions:
- Disturbance of the protein kinase-phosphatase system by OA is sufficient to induce neuronal cell cycle re-entry.
- OA forces neurons into mitosis, leading to mitotic catastrophe.
- These findings suggest a potential mechanism contributing to Alzheimer's disease pathogenesis.
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