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Effect of 50 Hz Extremely Low-Frequency Electromagnetic Fields on the DNA Methylation and DNA Methyltransferases in Mouse Spermatocyte-Derived Cell Line GC-2.

Liu Y, Liu WB, Liu KJ, Ao L, Zhong JL, Cao J, Liu JY - Biomed Res Int (2015)

Bottom Line: However, the biological effects and molecular mechanism are largely unclear.Our study was designed to elucidate the epigenetic effects of 50 Hz ELF-EMF in vitro.The expression of DNMT1 and DNMT3b was decreased at 1 mT, and 50 Hz ELF-EMF can increase the expression of DNMT1 and DNMT3b of GC-2 cells at 3 mT.

View Article: PubMed Central - PubMed

Affiliation: College of Bioengineering, Chongqing University, Chongqing 400044, China ; Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, China.

ABSTRACT
Previous studies have shown that the male reproductive system is one of the most sensitive organs to electromagnetic radiation. However, the biological effects and molecular mechanism are largely unclear. Our study was designed to elucidate the epigenetic effects of 50 Hz ELF-EMF in vitro. Mouse spermatocyte-derived GC-2 cell line was exposed to 50 Hz ELF-EMF (5 min on and 10 min off) at magnetic field intensity of 1 mT, 2 mT, and 3 mT with an intermittent exposure for 72 h. We found that 50 Hz ELF-EMF exposure decreased genome-wide methylation at 1 mT, but global methylation was higher at 3 mT compared with the controls. The expression of DNMT1 and DNMT3b was decreased at 1 mT, and 50 Hz ELF-EMF can increase the expression of DNMT1 and DNMT3b of GC-2 cells at 3 mT. However, 50 Hz ELF-EMF had little influence on the expression of DNMT3a. Then, we established DNA methylation and gene expression profiling and validated some genes with aberrant DNA methylation and expression at different intensity of 50 Hz ELF-EMF. These results suggest that the alterations of genome-wide methylation and DNMTs expression may play an important role in the biological effects of 50 Hz ELF-EMF exposure.

No MeSH data available.


Related in: MedlinePlus

Differentially methylated genes verified with methylation-specific PCR and real-time PCR in 50 Hz ELF-EMF exposure. (a) Representative MSP results of the three genes (Fut11, Olfr969A, and Tagln) methylation in GC-2 cells at magnetic field intensity of 1.0 mT. M: methylated primers; U: unmethylated primers. (b) Validation of mRNA expression of the three genes (Fut11, Olfr969A, and Tagln) by real-time PCR. (c) Representative MSP results of the three genes (Fut11, Olfr969B, and Lrrc9) methylation in GC-2 cells at magnetic intensity of 3.0 mT. (d) Validation of mRNA expression of the three genes (Fut11, Olfr969B, and Lrrc9) by real-time PCR.
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fig3: Differentially methylated genes verified with methylation-specific PCR and real-time PCR in 50 Hz ELF-EMF exposure. (a) Representative MSP results of the three genes (Fut11, Olfr969A, and Tagln) methylation in GC-2 cells at magnetic field intensity of 1.0 mT. M: methylated primers; U: unmethylated primers. (b) Validation of mRNA expression of the three genes (Fut11, Olfr969A, and Tagln) by real-time PCR. (c) Representative MSP results of the three genes (Fut11, Olfr969B, and Lrrc9) methylation in GC-2 cells at magnetic intensity of 3.0 mT. (d) Validation of mRNA expression of the three genes (Fut11, Olfr969B, and Lrrc9) by real-time PCR.

Mentions: In order to investigate the potential mechanism, we screened differential methylated sites in detail using Affymetrix Mouse promoter 1.0R Array. Genome-wide methylation profiling across 50 Hz ELF-EMF exposure and control group were shown in Figure 3. Array analysis revealed that thousands of gene acquired aberrant methylation exposed to 50 Hz ELF-EMF exposure (fold change > 2). Through DNA methylation chip analysis, there were a total of 296 differentially methylated sites (including 166 hypermethylation and 130 hypomethylation) in the 1 mT exposed group compared with the control group. In 3 mT group, there were only 70 differentially methylated sites, including 11 hypermethylated and 59 hypomethylated sites. The methylation status of differential methylation sites was confirmed by methylation-specific PCR and the mRNA expression of genes was validated by real-time PCR in Figure 3. As shown in Figure 3(a), we found that Fut11, Olfr969A, and Tagln showed hypermethylation in GC-2 cells at magnetic field intensity of 1.0 mT. The mRNA expression of those three genes was downregulated at 1.0 mT as shown in Figure 3(b). At the same time, Fut11 was hypermethylated, whereas Olfr969B and Lrrc9 were hypomethylated in GC-2 cells at magnetic intensity of 3.0 mT as shown in Figure 3(c). The mRNA expression of Fut11 showed downregulation and the expression level of Olfr969B and Lrrc9 was upregulated in GC-2 cells at magnetic field intensity of 3.0 mT (Figure 3(d)). These results suggest that the methylation status of these genes was inversely correlated with the mRNA expression in GC-2 cells exposed to 50 Hz ELF-EMF.


Effect of 50 Hz Extremely Low-Frequency Electromagnetic Fields on the DNA Methylation and DNA Methyltransferases in Mouse Spermatocyte-Derived Cell Line GC-2.

Liu Y, Liu WB, Liu KJ, Ao L, Zhong JL, Cao J, Liu JY - Biomed Res Int (2015)

Differentially methylated genes verified with methylation-specific PCR and real-time PCR in 50 Hz ELF-EMF exposure. (a) Representative MSP results of the three genes (Fut11, Olfr969A, and Tagln) methylation in GC-2 cells at magnetic field intensity of 1.0 mT. M: methylated primers; U: unmethylated primers. (b) Validation of mRNA expression of the three genes (Fut11, Olfr969A, and Tagln) by real-time PCR. (c) Representative MSP results of the three genes (Fut11, Olfr969B, and Lrrc9) methylation in GC-2 cells at magnetic intensity of 3.0 mT. (d) Validation of mRNA expression of the three genes (Fut11, Olfr969B, and Lrrc9) by real-time PCR.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4538330&req=5

fig3: Differentially methylated genes verified with methylation-specific PCR and real-time PCR in 50 Hz ELF-EMF exposure. (a) Representative MSP results of the three genes (Fut11, Olfr969A, and Tagln) methylation in GC-2 cells at magnetic field intensity of 1.0 mT. M: methylated primers; U: unmethylated primers. (b) Validation of mRNA expression of the three genes (Fut11, Olfr969A, and Tagln) by real-time PCR. (c) Representative MSP results of the three genes (Fut11, Olfr969B, and Lrrc9) methylation in GC-2 cells at magnetic intensity of 3.0 mT. (d) Validation of mRNA expression of the three genes (Fut11, Olfr969B, and Lrrc9) by real-time PCR.
Mentions: In order to investigate the potential mechanism, we screened differential methylated sites in detail using Affymetrix Mouse promoter 1.0R Array. Genome-wide methylation profiling across 50 Hz ELF-EMF exposure and control group were shown in Figure 3. Array analysis revealed that thousands of gene acquired aberrant methylation exposed to 50 Hz ELF-EMF exposure (fold change > 2). Through DNA methylation chip analysis, there were a total of 296 differentially methylated sites (including 166 hypermethylation and 130 hypomethylation) in the 1 mT exposed group compared with the control group. In 3 mT group, there were only 70 differentially methylated sites, including 11 hypermethylated and 59 hypomethylated sites. The methylation status of differential methylation sites was confirmed by methylation-specific PCR and the mRNA expression of genes was validated by real-time PCR in Figure 3. As shown in Figure 3(a), we found that Fut11, Olfr969A, and Tagln showed hypermethylation in GC-2 cells at magnetic field intensity of 1.0 mT. The mRNA expression of those three genes was downregulated at 1.0 mT as shown in Figure 3(b). At the same time, Fut11 was hypermethylated, whereas Olfr969B and Lrrc9 were hypomethylated in GC-2 cells at magnetic intensity of 3.0 mT as shown in Figure 3(c). The mRNA expression of Fut11 showed downregulation and the expression level of Olfr969B and Lrrc9 was upregulated in GC-2 cells at magnetic field intensity of 3.0 mT (Figure 3(d)). These results suggest that the methylation status of these genes was inversely correlated with the mRNA expression in GC-2 cells exposed to 50 Hz ELF-EMF.

Bottom Line: However, the biological effects and molecular mechanism are largely unclear.Our study was designed to elucidate the epigenetic effects of 50 Hz ELF-EMF in vitro.The expression of DNMT1 and DNMT3b was decreased at 1 mT, and 50 Hz ELF-EMF can increase the expression of DNMT1 and DNMT3b of GC-2 cells at 3 mT.

View Article: PubMed Central - PubMed

Affiliation: College of Bioengineering, Chongqing University, Chongqing 400044, China ; Institute of Toxicology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, China.

ABSTRACT
Previous studies have shown that the male reproductive system is one of the most sensitive organs to electromagnetic radiation. However, the biological effects and molecular mechanism are largely unclear. Our study was designed to elucidate the epigenetic effects of 50 Hz ELF-EMF in vitro. Mouse spermatocyte-derived GC-2 cell line was exposed to 50 Hz ELF-EMF (5 min on and 10 min off) at magnetic field intensity of 1 mT, 2 mT, and 3 mT with an intermittent exposure for 72 h. We found that 50 Hz ELF-EMF exposure decreased genome-wide methylation at 1 mT, but global methylation was higher at 3 mT compared with the controls. The expression of DNMT1 and DNMT3b was decreased at 1 mT, and 50 Hz ELF-EMF can increase the expression of DNMT1 and DNMT3b of GC-2 cells at 3 mT. However, 50 Hz ELF-EMF had little influence on the expression of DNMT3a. Then, we established DNA methylation and gene expression profiling and validated some genes with aberrant DNA methylation and expression at different intensity of 50 Hz ELF-EMF. These results suggest that the alterations of genome-wide methylation and DNMTs expression may play an important role in the biological effects of 50 Hz ELF-EMF exposure.

No MeSH data available.


Related in: MedlinePlus