Impact of 60-GHz millimeter waves on stress and pain-related protein expression in differentiating neuron-like cells

International audienceMillimeter waves (MMW) will be increasingly used for future wireless telecommunications. Previous studies on skin keratinocytes showed that MMW could impact the mRNA expression of Transient Receptor Potential cation channel subfamily Vanilloid, member 2 (TRPV2). Here, we investigated the effect of MMW exposure on this marker, as well as on other membrane receptors such as Transient Receptor Potential cation channel subfamily Vanilloid, member 1 (TRPV1) and purinergic receptor P2X, ligand-gated ion channel, 3 (P2 × 3). We exposed the Neuroscreen-1 cell line (a PC12 subclone), in order to evaluate if acute MMW exposures could impact expression of these membrane receptors at the protein level. Proteotoxic stress-related chaperone protein Heat Shock Protein 70 (HSP70) expression level was also assessed. We used an original high-content screening approach, based on fluorescence microscopy, to allow cell-by-cell analysis and to detect any cell sub-population responding to exposure. Immunocytochemistry was done after 24 h MMW exposure of cells at 60.4 GHz, with an incident power density of 10 mW/cm2. Our results showed no impact of MMW exposure on protein expressions of HSP70, TRPV1, TRPV2, and P2 × 3. Moreover, no specific cell sub-populations were found to express one of the studied markers at a different level, compared to the rest of the cell populations. However, a slight insignificant increase in HSP70 expression and an increase in protein expression variability within cell population were observed in exposed cells, but controls showed that this was related to thermal effect. Bioelectromagnetics. 37:444–454, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc

Eukaryotic conditional expression system

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Steroidogenic factor 1 and estradiol receptor act in synergism to regulate the expression of the salmon gonadotropin IIβ subunit gene

The orphan nuclear receptor steroidogenic factor-1 (SF-1) regulates the expression of several genes involved in the reproductive function and development of the adrenal, the gonads, and the pituitary gonadotropes. It also confers the gonadotrope-specific expression of the glycoprotein hormone α subunit gene by the binding to a gonadotrope-specific element (GSE). In this study, we have shown that SF-1 transactivates the salmon gonadotropin IIβ subunit (sGTHIIβ) gene expression. SF-1 alone offered a slight but significant enhancement on sGTHIIβ promoter activity (7.2 ± 0.6 fold). However, it stimulated sGTHIIβ gene expression dramatically (127 ± 37 fold) when combined with the estrogen receptor (ER). This synergistic interaction was specific for sGTHIIβ promoter as well as for both SF-1 and ER and was estradiol-dose dependent. 5'-Deletion studies of the sGTHIIβ promoter identified two putative SF-1 binding sites (GSE) and one previously identified proximal estrogen-responsive element (pERE) at -274 bp involved in this activation. The two GSE sequences located at -354 bp (sGSE 3) and -162 bp (sGSE 2) upstream of the transcription site, although imperfect as compared with the consensus GSE, bound specifically to the in vitro- translated mouse SF-1 protein. 5'-Deletion studies, competition experiments, and site-directed mutagenesis showed that binding to pERE and GSE 2 were necessary for the SF-1/ER synergistic effect. These studies suggest that the synergistic interaction of SF-1 and ER, possibly through cooperative binding or protein-protein interaction, is essential in conferring a cell type- specific expression of the GTHIIβ subunit gene.published_or_final_versio

Electromagnetic fields: from dosimetry to human health. State of knowledge on biological effects at 40-60 GHz

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Effect of acute millimeter wave exposure on dopamine metabolism of NGF-treated PC12 cells

International audienceSeveral forthcoming wireless telecommunication systems will use electromagnetic frequencies at millimeter waves (MMWs), and technologies developed around the 60-GHz band will soon know a widespread distribution. Free nerve endings within the skin have been suggested to be the targets of MMW therapy which has been used in the former Soviet Union. So far, no studies have assessed the impact of MMW exposure on neuronal metabolism. Here, we investigated the effects of a 24-h MMW exposure at 60.4 GHz, with an incident power density (IPD) of 5 mW/cm2, on the dopaminergic turnover of NGF-treated PC12 cells. After MMW exposure, both intracellular and extracellular contents of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were studied using high performance liquid chromatography. Impact of exposure on the dopamine transporter (DAT) expression was also assessed by immunocytochemistry. We analyzed the dopamine turnover by assessing the ratio of DOPAC to DA, and measuring DOPAC accumulation in the medium. Neither dopamine turnover nor DAT protein expression level were impacted by MMW exposure. However, extracellular accumulation of DOPAC was found to be slightly increased, but not significantly. This result was related to the thermal effect, and overall, no evidence of non-thermal effects of MMW exposure were observed on dopamine metabolism. © 2017 The Author. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology

Electromagnetic fields: from dosimetry to human health. State of knowledge on biological effects at 40-60 GHz

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Experimental set-up for exposure of cell cultures in vitro to pulse-modulated RF signals of ultra high field MRI

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