Study of extremely low frequency electromagnetic field (ELF-EMF) responses of human HaCaT keratinocytes: Control vs. ELF-EMF
ABSTRACT: Use DNA microarray technology to discover transciprtional insights of HaCaT for continuous exposure to ELF-EMF We used a loop design in this study (details in the 'loop_design.tiff' supplementary file), cDNA microarray experiment consisted of ten RNA samples, including ELF-EMF exposed, UVB irradiated (positive control), and sham exposed samples.
Project description:The potential health hazard of exposures to electromagnetic fields (EMF) continues to cause much public concern. However, the biological and health effects of exposures to EMF remain controversial and their biophysical mechanisms are unclear. In the present study, we used Saccharomyces cerevisiae to identify genes responding to extremely low frequency magnetic fields (ELF-MF) and to radiofrequency (RF) EMF exposures. The expression of genes was analyzed by microarray screening and confirmed by real-time reverse transcription -polymerase chain reaction. In confirmation experiments, we found that there was no statistically significant change in three of the ELF-MF responsive candidate genes (P>0.05). On the other hand, out of the forty genes that responded to RF-EMF, the confirmation experiments found that only five were affected: structural maintenance of chromosomes 3-gene (SMC3), aquaporin 2 –gene (AQY2), halotolerance protein 9 –gene (HAL9), yet another kinase 1 -gene (YAK1) and one of unknown function gene (open reading frame: YJL171C) (P<0.05). Overall, this study has demonstrated that the yeast cells did not respond to 50 Hz ELF-MF and that the response to RF-EMF is limited to only five genes. The biological consequences of the observed gene expression changes induced by RF-EMF await further investigation. The yeast cells were exposed to 0.4 mT 50 Hz ELF-MF or 1800 MHz RF-EMF at a specific absorption rate of 3.5 W/kg for 6 hours.
Project description:Aberrant miRNA expression has been related to the development of human germ cell tumors, but little is known about effect of ELF-EMFs on miRNA expression. ELF-EMFs may epigenetically modify cells, which may account for the adverse effects of ELF-EMFs on the male reproductive system. To identify miRNAs that were differentially expressed between the sham and ELF-EMF exposure groups, we performed an Affymetrix microarray analysis to establish the miRNA expression profiles. Mouse spermatocyte-derived GC-2 cells were intermittently exposed to a 50 Hz ELF-EMF for 72 h (5 min on/10 min off) at magnetic field intensities of 1 mT and 3 mT. miRNA expression was profiled using Affymetrix Mouse Genechip miRNA 3.0 arrays.
Project description:Consistent and independently replicated laboratory evidence to support a causative relationship between environmental exposure to extremely low frequency electromagnetic fields (ELF-EMF) at power line frequencies and the associated increase in risk of childhood leukaemia has not been obtained. In particular, although gene expression responses have been reported in a wide variety of cells, none have emerged as robust, widely replicated effects. DNA microarrays facilitate comprehensive searches for changes in gene expression without a requirement to select candidate responsive genes. To determine if gene expression changes occur in white blood cells of volunteers exposed to an ELF-EMF, each of 17 pairs of male volunteers age 20-30 was subjected either to a 50 Hz EMF exposure of 62.0 ± 7.1 μT for 2 h or to a sham exposure (0.21 ± 0.05 μT) at the same time (11:00-13:00). The alternative regime for each volunteer was repeated on the following day and the two-day sequence was repeated 6 days later except that a null exposure (0.085 ± 0.01 μT) replaced the sham exposure. Five blood samples (10 ml) were collected at 2 h intervals from 9:00 to 17:00 with five additional samples during the exposure and sham or null exposure periods on each study day at 11.05, 11.10, 11.20, 11.40 and 12.20. RNA samples were pooled for the same time points on each study day for the 17 volunteers that were subjected to the ELF-EMF exposure/sham or null exposure sequence and were analysed on Illumina microarrays. Time courses for 16 mammalian genes previously reported to be responsive to ELF-EMF exposure, including immediate early genes, stress response, cell proliferation and apoptotic genes were examined in detail. No genes or gene sets significantly expressed on the arrays showed consistent response profiles to repeated ELF-EMF exposures. A stress response was detected as a transient increase in plasma cortisol at the onset of either exposure or sham exposure on the first study day. The cortisol response diminished progressively on subsequent exposures or sham exposures and was attributable to mild stress associated with the experimental protocol. The study design described in the summary gave a total of 40 pooled RNA samples (10 for each study day) using equal amounts of RNA from the 17 volunteers exposed to ELF-EMF on study days 1 and 3, a sham exposure on study day 2 and a null exposures on study day 4. The pooled sample from 11:00 on Day1 (immediately prior to ELF-EMF exposure) was used as a reference sample that was amplified and labelled 4 times with the other samples from each of the 4 study days (titled as replicates 1 to 4). Each replicate was hybridised twice (titled replicates a and b for each day ( e.g. 1a, 1b) to give a total of 8 arrays from the reference RNA sample (Sample names 2 and 41-47, i.e.GSM879110-GSM879117).
Project description:Graphene-based substrate has efficient neuronal differentiation of hMSCs. Stimulatory effects of graphene on hMSCs neurogenesis can be enhanced by ELF-EMF exposure and it is mediated by enhancement of cell adhesion accompanied by intracellular signal pathway. We used microarrays to assess up-regulated genes in human gene expression profiles during neurogenesis induced by ELF-EMF exposure on graphene. 3 groups (HMSCs grown in neuronal medium on glass, graphene, graphene under ELF-EMF exposure) were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain total human gene expression. To that end, we hand-selected up-regulated gene involved in neurogenesis, extracellular matrix, and cell migration.
Project description:The ami of this study was to investigate the possible biological effects of ELF-EMF by cDNA microarray. Keywords: ELF-EMF, cDNA microarray, keratinocyte, cytoskeleton Overall design: We used a loop design for the microarray study. In this design, there are five sample sets introduced: a sample set without treatment (Ctrl), two identical sample sets with ELF-EMF exposure (EMF), a sample set with UVB irradiation (UV), and a sample set with UVB irradiation followed by ELF-EMF exposure (UE). We hybridized each slide with labeled RNA from two sample sets, the RNA of one sample was labeled with Cy3 and the RNA of the other sample was labeled with Cy5.
Project description:Clinical evidence has shown that electromagnetic fields produce a benefical therapeutic result for wounds, however little is still known about their exact mechanism of action. Moreover, clinical results concerning skin tissue restoration are still debated. In the present study, we carried out gene expression profiling of a human keratinocyte line (HaCaT) submitted to 1 hour of ELF-EMF (frequency 50Hz, intensity 1 mT) in order to identify up- and downregulated genes by this stimulus, and to verify the presence of specific molecular pathways activation. Most of the genes modulated were involved in mechanisms such as protein synthesis. In particular, these genes are related to Mammalian target of Rapamycin (mTOR), which has been identified as a kinase with a pivotal role in cellular proliferation and survival in mammals. In this study, we analyzed the expression profiles of 3 biological replicates of HaCaT cells exposed to ELF-EMF (frequency 50Hz, intensity 1 mT) for 1 hour. All HaCaT cells exposed to ELF-EMF RNAs were hybridized against control sham-exposed HaCaT cells RNAs. Each biological sample was repeated with a technical replicate (extraction-labeling) and a dye-swap experiment.
Project description:The potential health hazard of exposures to electromagnetic fields (EMF) continues to cause much public concern. However, the biological and health effects of exposures to EMF remain controversial and their biophysical mechanisms are unclear. In the present study, we used Saccharomyces cerevisiae to identify genes responding to extremely low frequency magnetic fields (ELF-MF) and to radiofrequency (RF) EMF exposures. The expression of genes was analyzed by microarray screening and confirmed by real-time reverse transcription -polymerase chain reaction. In confirmation experiments, we found that there was no statistically significant change in three of the ELF-MF responsive candidate genes (P>0.05). On the other hand, out of the forty genes that responded to RF-EMF, the confirmation experiments found that only five were affected: structural maintenance of chromosomes 3-gene (SMC3), aquaporin 2 –gene (AQY2), halotolerance protein 9 –gene (HAL9), yet another kinase 1 -gene (YAK1) and one of unknown function gene (open reading frame: YJL171C) (P<0.05). Overall, this study has demonstrated that the yeast cells did not respond to 50 Hz ELF-MF and that the response to RF-EMF is limited to only five genes. The biological consequences of the observed gene expression changes induced by RF-EMF await further investigation. Overall design: The yeast cells were exposed to 0.4 mT 50 Hz ELF-MF or 1800 MHz RF-EMF at a specific absorption rate of 3.5 W/kg for 6 hours.
Project description:Previous studies showed that SV40 transformed cells have unique DNA damage responses; further inspecting these responses by microarray provides an opportunity to discover transciprtional insights of DNA damage responses after UVB irradiation. This study is used to comapre to GSE7589, our previous study of human normal lung fibroblast after UVB irradiation. We used a loop design in this study, cDNA microarray experiment consisted of eight RNA samples, including UVB-irradiated samples and their corresponding controls of 4 time points after UV irradiation.
Project description:Variance in microarray studies has been widely discussed as a critical topic of the identification of differentially expressed gene; however, few studies have addressed the influence of estimating variance. To break intra- and inter-individual variance in clinical studies down to three levels: technical, anatomic, and individual, we designed experiments and algorithms to investigate three forms of variances. As a case study, a group of “inter-individual variable genes” were identified to exemplify the influence of underestimated variance on the statistical and biological aspects in identification of differentially expressed genes. Our results showed that inadequate estimation of variance inevitably led to the inclusion of non-statistically significant genes into those listed as significant, thereby interfering with the correct prediction of biological functions. Applying a higher cutoff value of fold changes in the selection of significant genes reduce/eliminate the effects of underestimated variance. Our data demonstrates that an appropriate evaluation of variance is critical in selecting significant genes of differential expression. If the estimation of precise variance has not been adequately considered in the experimental design, using a higher fold change criteria is one possible solution to overcome the difficulties associated with the identification of significant genes, but it paid by losing the number of selected genes. A total of 11 normal placenta tissues obtained from 9 healthy individuals with term pregnancies, whom underwent cesarean section without labor pain. The first sample group (G1) was composed of samples 1 to 9 of nine individuals. The second sample group (G2) contained 8-1, 8-2 and 8-3, which were three different placental tissues taken from the same individual. The third sample group (G3) consisted of two technical replicates, 8-3_1 and 8-3_2, using the identical RNA pool. Sample 8-3 is estimated by sample 8-3_1 and 8-3_2. Sample 8 is estimated by sample 8-1, 8-2 and 8-3.
Project description:We investigated whether biomarker analysis in endobronchial epithelial lining fluid (ELF) collected by bronchoscopic microsampling may be useful for a definitive preoperative diagnosis. Therefore we compared ELF samples close to nodule and from the contralateral site from patients with malignant or benign diagnosis. ELF samples have been derived from early stage NSCLC patients and controls. Wilcox Test was performed to identify differentially expressed genes associated to a malignant diagnosis. key words: disease subtype analysis