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Kainic acid-induced neuronal loss and glial changes in the hippocampal CA3 of p53-deficient mouse
Y Kitamura1, T Ota, Y Matsuoka
1Department of Neurobiology, Kyoto Pharmaceutical University, Japan.
Abstract:
We examined kainic acid (KA)-induced neuronal death and changes in glial cells in p53-deficient (p53-/-) and wild-type (p53+/+) mice which were CBA and C57BL/6 background. The p53-/- mouse exhibited a KA-induced loss of CA3 pyramidal neurons similar to that in wild-type mouse. Before neuronal death, c-Jun protein was expressed, phosphorylated and translocated into several nuclei of CA3 pyramidal neurons. In p53-/- mouse, microglial activation was slightly faster and more continuous after 1-7 days than that in p53+/+ mouse. On the other hand, p53-/- astrocytes were relatively resistant to KA cytotoxicity, and marked astrocytosis also occurred after 7 days. These observations suggest that p53-null mutation may influence the activation and proliferation of glial cells rather than neuronal death.
Insights
The p53 gene mutation did not affect kainic acid-induced neuronal death but altered glial cell responses. p53-deficient mice showed faster microglial activation and resistant astrocytes, suggesting p53 influences glial cell activity.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Kainic acid (KA) is a neurotoxin that induces excitotoxicity and neuronal death, particularly in the hippocampus.
- The p53 protein is a tumor suppressor involved in cellular responses to stress, including DNA damage and apoptosis.
- Glial cells, including microglia and astrocytes, play critical roles in neuroinflammation and neuronal support.
Purpose of the Study:
- To investigate the role of the p53 gene in kainic acid-induced neuronal death.
- To examine the impact of p53 deficiency on glial cell activation and proliferation following KA administration.
- To compare the responses of p53-deficient and wild-type mice to KA-induced neurotoxicity.
Main Methods:
- Kainic acid (KA) was administered to p53-deficient (p53-/-) and wild-type (p53+/+) mice on CBA and C57BL/6 backgrounds.
- Neuronal death in the CA3 region of the hippocampus was assessed.
- Expression, phosphorylation, and nuclear translocation of c-Jun protein were examined.
- Microglial activation and astrocytosis were evaluated at various time points post-KA administration.
Main Results:
- p53-/- mice exhibited KA-induced CA3 pyramidal neuron loss comparable to wild-type mice.
- c-Jun protein expression, phosphorylation, and nuclear translocation preceded neuronal death.
- Microglial activation was more rapid and sustained in p53-/- mice compared to p53+/+ mice.
- p53-/- astrocytes demonstrated relative resistance to KA cytotoxicity, with significant astrocytosis observed after 7 days.
Conclusions:
- The p53-null mutation does not significantly alter KA-induced neuronal death.
- p53 deficiency appears to modulate the activation and proliferation dynamics of microglial cells and astrocytes.
- These findings suggest that p53 plays a role in regulating glial cell responses to excitotoxic injury.