The effect of Repetitive Magnetic stimulation on Gene Expression in Neuronal Cells

Abstract

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and painless tool that can be used to various neuropychiatric and neurorehabilitation disorders. Although rTMS is widely used in clinical field, precise biological mechanism and effectiveness is not well known. Therefore, the current study examined the temporal changes in global gene expression pattern depending on differential effects of repetitive magnetic stimulation (rMS) in neuronal cell to generate a comprehensive view of the mechanisms. Neuro 2a (mouse neuroblastoma cell line) cells were used as the cell model in this study. Dishes of cultured cells were randomly divided into three groups : sham, low-frequency (0.5 Hz) and high-frequency (10 Hz) and were stimulated for 3 days. Three groups were systematically characterized the transcriptome analysis. Differentially expressed genes (DEG), the result of transcriptome analysis, were then analyzed by a program Database of Annotation Visualization and Integrated Discovery (DAVID), which yielded Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. DEG was validated by qRT-PCR & western blot. Comparing between low-frequency and high-frequency of rMS, long-term potentiation, neurotrophin signaling pathway, cholinergic synapse, dopaminergic synapse were shown as the enriched significant pathways. Grin1, Camk2d and Camk2a were increased, and Camk2g was decreased. These genes can activate the Ca2+-CaMKII-CREB pathway. Furthermore, high frequency of rMS increased phosphorylation of cAMP-response element binding protein (p-CREB), BDNF transcription and synaptic marker protein expression via activation of CaMKII-CREB pathway in neuro 2a cells. Taken together, these data established the mechanisms of Ca2+-CaMKII-CREB signaling pathway, which can be regulated by rMS in neuro 2a cells depending on different frequencies. These findings might help clarify further therapeutic mechanisms of rTMS.