title: Assessing the combined effect of extremely low-frequency magnetic field exposure and oxidative stress on LINE-1 promoter methylation in human neural cells.
abstract: Extremely low frequency magnetic fields (ELF-MF) have been classified as "possibly carcinogenic", but their genotoxic effects are still unclear. Recent findings indicate that epigenetic mechanisms contribute to the genome dysfunction and it is well known that they are affected by environmental factors. To our knowledge, to date the question of whether exposure to ELF-MF can influence epigenetic modifications has been poorly addressed. In this paper, we investigated whether exposure to ELF-MF alone and in combination with oxidative stress (OS) can affect DNA methylation, which is one of the most often studied epigenetic modification. To this end, we analyzed the DNA methylation levels of the 5'untranslated region (5'UTR) of long interspersed nuclear element-1s (LINE-1 or L1), which are commonly used to evaluate the global genome methylation level. Human neural cells (BE(2)C) were exposed for 24 and 48 h to extremely low frequency pulsed magnetic field (PMF; 50 Hz, 1 mT) in combination with OS. The methylation levels of CpGs located in L1 5'UTR region were measured by MassARRAY EpiTYPER. The results indicate that exposures to the single agents PMF and OS induced weak decreases and increases of DNA methylation levels at different CpGs. However, the combined exposure to PMF and OS lead to significant decrease of DNA methylation levels at different CpG sites. Most of the changes were transient, suggesting that cells can restore homeostatic DNA methylation patterns. The results are discussed and future research directions outlined.
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Giorgi
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, via S. Giacomo 12, 40126, Bologna, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Pirazzini
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, via S. Giacomo 12, 40126, Bologna, Italy.
authors.forename: Maria Giulia
authors.initials: MG
authors.lastname: Bacalini
authors.affiliation: Department of Biological, Geological and Environmental Sciences (BiGeA), Centre for Genome Biology, University of Bologna, via Selmi 3, 40126, Bologna, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Giuliani
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, via S. Giacomo 12, 40126, Bologna, Italy.|CIG-Interdepartmental Centre "L. Galvani" for Bioinformatics, Biophysics and Biocomplexity, Piazza di Porta San Donato 1, 40126, Bologna, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Garagnani
authors.affiliation: Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, via S. Giacomo 12, 40126, Bologna, Italy.|CIG-Interdepartmental Centre "L. Galvani" for Bioinformatics, Biophysics and Biocomplexity, Piazza di Porta San Donato 1, 40126, Bologna, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Capri
authors.affiliation: DIFA Department of Physics and Astronomy, University of Bologna, via Berti Pichat 6/2, 40127, Bologna, Italy.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Bersani
authors.affiliation: Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, via Selmi 3, 40126, Bologna, Italy. brunella.delre@unibo.it.
authors.forename: Brunella
authors.initials: B
authors.lastname: Del Re
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D019175:DNA Methylation; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D060526:Magnetic Fields; D009474:Neurons / Q000378:metabolism*; D018384:Oxidative Stress; D011401:Promoter Regions, Genetic / Q000235:genetics*; D013997:Time Factors
keywords: DNA methylation; Epigenetics; Extremely low frequency magnetic field; LINE-1; Oxidative stress; Retrotransposition