Millimeter Waves Modulate the Transcriptome in Human Fibroblasts

Millimetre-wave (MMW) frequencies of the electromagnetic spectrum are increasingly being adopted in modern technologies including mobile communications, networking, and security screening. These frequencies are absorbed by the outer layers of the skin, however the biological effects are not well characterised. Thus, as emerging technologies increase human exposure, understanding the effects of MMWs on biological material and cell biology in the skin is critical in determining safe exposure levels. Here, we report on the exposure of primary human dermal fibroblasts to MMWs; we find that the radiation triggers genomic and transcriptomic alterations. In particular, repeated 60 GHz MMW exposures at 2.6 mW cm-2, 46.8 J cm-2 doses, trigger a physiological response in human fibroblasts distinct from conventional cytokine-induced stimulation. Our results show that high dose MMWs induce non-thermal transcriptomic alterations with simultaneous changes in DNA structural dynamics including formation of G-quadruplex and i-motif secondary structures, but not DNA damage. Overall design: RNA-seq of primary human fibroblasts exposed to 60 GHz MMWs for 5 h/day for 2 days