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Updated: Mar 26, 2026
Isolation and Culture of Embryonic Mouse Neural Stem Cells
Published on: November 11, 2018
Ionizing Radiation Induces Altered Neuronal Differentiation by mGluR1 through PI3K-STAT3 Signaling in C17.2 Mouse
Hyeon Soo Eom1,2, Hae Ran Park1,3, Sung Kee Jo1,3
1Radiation Biotechnology Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea.
Abstract:
Most studies of IR effects on neural cells and tissues in the brain are still focused on loss of neural stem cells. On the other hand, the effects of IR on neuronal differentiation and its implication in IR-induced brain damage are not well defined. To investigate the effects of IR on C17.2 mouse neural stem-like cells and mouse primary neural stem cells, neurite outgrowth and expression of neuronal markers and neuronal function-related genes were examined. To understand this process, the signaling pathways including PI3K, STAT3, metabotrophic glutamate receptor 1 (mGluR1) and p53 were investigated. In C17.2 cells, irradiation significantly increased the neurite outgrowth, a morphological hallmark of neuronal differentiation, in a dose-dependent manner. Also, the expression levels of neuronal marker proteins, β-III tubulin were increased by IR. To investigate whether IR-induced differentiation is normal, the expression of neuronal function-related genes including synaptophysin, a synaptic vesicle forming proteins, synaptotagmin1, a calcium ion sensor, γ-aminobutyric acid (GABA) receptors, inhibitory neurotransmitter receptors and glutamate receptors, excitatory neurotransmitter receptors was examined and compared to that of neurotrophin-stimulated differentiation. IR increased the expression of synaptophysin, synaptotagmin1 and GABA receptors mRNA similarly to normal differentiation by stimulation of neurotrophin. Interestingly, the overall expression of glutamate receptors was significantly higher in irradiated group than normal differentiation group, suggesting that the IR-induced neuronal differentiation may cause altered neuronal function in C17.2 cells. Next, the molecular mechanism of the altered neuronal differentiation induced by IR was studied by investigating signaling pathways including p53, mGluR1, STAT3 and PI3K. Increases of neurite outgrowth, neuronal marker and neuronal function-related gene expressions by IR were abolished by inhibition of p53, mGluR-1, STAT3 or PI3K. The inhibition of PI3K blocked both p53 signaling and STAT3-mGluR1 signaling but inhibition of p53 did not affect STAT3-mGluR1 signaling in irradiated C17.2 cells. Finally, these results of the IR-induced altered differentiation in C17.2 cells were verified in ex vivo experiments using mouse primary neural stem cells. In conclusion, the results of this study demonstrated that IR is able to trigger the altered neuronal differentiation in undifferentiated neural stem-like cells through PI3K-STAT3-mGluR1 and PI3K-p53 signaling. It is suggested that the IR-induced altered neuronal differentiation may play a role in the brain dysfunction caused by IR.
Insights
Ionizing radiation (IR) promotes neurite outgrowth and neuronal marker expression in neural stem cells. This IR-induced differentiation may alter neuronal function and contribute to brain damage via PI3K-STAT3-mGluR1 and PI3K-p53 signaling pathways.
Area of Science:
- Neuroscience
- Cell Biology
- Radiation Biology
Background:
- Research on ionizing radiation (IR) effects on brain cells primarily focuses on neural stem cell loss.
- The impact of IR on neuronal differentiation and its role in IR-induced brain damage remain poorly understood.
- Understanding IR's influence on neural stem cell differentiation is crucial for assessing potential brain damage.
Purpose of the Study:
- To investigate the effects of IR on neuronal differentiation in C17.2 mouse neural stem-like cells and primary mouse neural stem cells.
- To examine the molecular mechanisms, including signaling pathways (PI3K, STAT3, mGluR1, p53), underlying IR-induced neuronal differentiation.
- To determine if IR-induced neuronal differentiation leads to altered neuronal function.
Main Methods:
- Assessed neurite outgrowth and expression of neuronal markers (e.g., β-III tubulin) in irradiated C17.2 cells.
- Examined the expression of neuronal function-related genes (synaptophysin, synaptotagmin1, GABA receptors, glutamate receptors).
- Investigated the roles of PI3K, STAT3, mGluR1, and p53 signaling pathways in IR-induced differentiation using inhibitors.
- Validated findings in ex vivo experiments with mouse primary neural stem cells.
Main Results:
- Irradiation significantly increased neurite outgrowth and β-III tubulin expression in C17.2 cells in a dose-dependent manner.
- IR upregulated synaptophysin, synaptotagmin1, and GABA receptor mRNA, similar to neurotrophin-induced differentiation.
- Glutamate receptor expression was significantly higher in IR-treated cells compared to neurotrophin-treated cells, suggesting altered neuronal function.
- Inhibition of p53, mGluR1, STAT3, or PI3K abolished IR-induced increases in differentiation markers.
- PI3K inhibition affected both p53 and STAT3-mGluR1 signaling, while p53 inhibition did not affect STAT3-mGluR1 signaling.
Conclusions:
- Ionizing radiation triggers altered neuronal differentiation in neural stem-like cells via PI3K-STAT3-mGluR1 and PI3K-p53 signaling pathways.
- IR-induced neuronal differentiation may contribute to brain dysfunction following radiation exposure.
- These findings highlight a novel mechanism of IR-induced neural alterations beyond stem cell loss.
