Mammalian stem cells respond to terahertz radiation with changes in gene expression

We report that extended exposure to broad-spectrum terahertz radiation results in specific changes in cellular functions that are closely related to DNA-directed gene transcription. Our gene chip survey of gene expression shows that whereas 89% of the protein coding genes in mouse stem cells do not respond to the applied teraherz radiation, certain genes are activated, while other are repressed. RT-PCR experiments with selected gene probes corresponding to transcripts in the three groups of genes detail the gene specific effect. The response was not only gene specific but also irradiation conditions dependent. Our findings suggest that the applied terahertz irradiation accelerates cell differentiation toward adipose phenotype by activating the transcription factor peroxisome proliferator-activated receptor gamma (PPARG). Finally, our molecular dynamics computer simulations indicate that the local breathing dynamics of the PPARG promoter DNA coincides with the gene specific response to the THz radiation. We propose that THz radiation is a potential tool for cellular reprogramming. Growing in petri dish mouse mesenchymal stem cell culture is irradiated with THz radiation for 9 hours. Nonirradiated cells are used as a control. Immediately after irradiation total RNA is isolated from both THz treated and untreated cells. We used miroarrays to identify genes that are changing cellular level in response to THz radiation.