Ionizing radiation causes increased tau phosphorylation in primary neurons

Area of Science:

• Neuroscience
• Radiation Oncology
• Molecular Biology

Background:

• Radiotherapy for brain tumors uses ionizing radiation, which can cause long-term neurological damage.
• Alzheimer's disease and related disorders are potential late effects of radiation exposure.
• Tau protein phosphorylation is a hallmark of Alzheimer's disease.

Purpose of the Study:

• To investigate if ionizing radiation induces tau phosphorylation in cultured neurons, mimicking Alzheimer's disease pathology.
• To identify the molecular pathways involved in radiation-induced tau phosphorylation.

Main Methods:

• Exposure of cultured primary neurons to varying doses (0.5 and 2 Gy) of gamma rays.
• Analysis of tau protein phosphorylation at specific sites.
• Assay of kinase activation (GSK3β, JNK, ERK) and assessment of inhibitor effects.
• Evaluation of the role of oxidative stress.

Main Results:

• Ionizing radiation significantly increased tau phosphorylation in a time- and dose-dependent manner.
• Radiation elevated the activity of GSK3β, JNK, and ERK kinases preceding tau phosphorylation.
• Kinase inhibitors largely prevented radiation-induced tau phosphorylation.
• Oxidative stress was implicated in radiation-induced tau phosphorylation via JNK and ERK activation.

Conclusions:

• Ionizing radiation promotes abnormal tau phosphorylation in neurons.
• The findings suggest a mechanism by which radiotherapy may increase the risk of developing Alzheimer's disease.
• Targeting specific kinases and oxidative stress pathways could mitigate radiation-induced neurodegeneration.