DNA methylation and gene expression can be altered by early life stress (ELS) and/or ethanol consumption. The present study aimed to investigate whether DNA methylation of the Vesicular Glutamate Transporters (Vglut)1–3 is related to previously observed Vglut1-3 transcriptional differences in the ventral tegmental area (VTA), nucleus accumbens (Acb), dorsal striatum (dStr) and medial prefrontal cortex (mPFC) of adult rats exposed to ELS, modelled by maternal separation, and voluntary ethanol consumption. Targeted next-generation bisulfite sequencing was performed to identify the methylation levels on 61 5′-cytosine-phosphate-guanosine-3′ sites (CpGs) in potential regulatory regions of Vglut1, 53 for Vglut2, and 51 for Vglut3. In the VTA, ELS in ethanol-drinking rats was associated with Vglut1-2 CpG-specific hypomethylation, whereas bidirectional Vglut2 methylation differences at single CpGs were associated with ELS alone. Exposure to both ELS and ethanol, in the Acb, was associated with lower promoter and higher intronic Vglut3 methylation; and in the dStr, with higher and lower methylation in 26% and 43% of the analyzed Vglut1 CpGs, respectively. In the mPFC, lower Vglut2 methylation was observed upon ELS- or ethanol-only. The present findings suggest Vglut1-3 CpG-specific methylation signatures of ELS and ethanol drinking, underlying previously reported Vglut1-3 transcriptional differences in the mesocorticolimbic brain.
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Competing interest reported. : LY is key shareholder of EpigenDx; all genetic analyses were performed in a blind manner. The other authors have no conflict of interest to declare.
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Supplementary Material
Table 1. Correlations between CpG methylation and gene expression as well as blood corticosterone levels for Slc17a7/Vglut1 and Slc17a6/Vglut2 genes in the VTA by group. The color bar indicates the Spearman´s rho coefficient; * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001
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Posted 11 Mar, 2021
Received 05 Apr, 2021
On 19 Mar, 2021
On 19 Mar, 2021
On 19 Mar, 2021
Invitations sent on 19 Mar, 2021
On 15 Mar, 2021
On 03 Mar, 2021
On 03 Mar, 2021
On 26 Feb, 2021
Posted 11 Mar, 2021
Received 05 Apr, 2021
On 19 Mar, 2021
On 19 Mar, 2021
On 19 Mar, 2021
Invitations sent on 19 Mar, 2021
On 15 Mar, 2021
On 03 Mar, 2021
On 03 Mar, 2021
On 26 Feb, 2021
DNA methylation and gene expression can be altered by early life stress (ELS) and/or ethanol consumption. The present study aimed to investigate whether DNA methylation of the Vesicular Glutamate Transporters (Vglut)1–3 is related to previously observed Vglut1-3 transcriptional differences in the ventral tegmental area (VTA), nucleus accumbens (Acb), dorsal striatum (dStr) and medial prefrontal cortex (mPFC) of adult rats exposed to ELS, modelled by maternal separation, and voluntary ethanol consumption. Targeted next-generation bisulfite sequencing was performed to identify the methylation levels on 61 5′-cytosine-phosphate-guanosine-3′ sites (CpGs) in potential regulatory regions of Vglut1, 53 for Vglut2, and 51 for Vglut3. In the VTA, ELS in ethanol-drinking rats was associated with Vglut1-2 CpG-specific hypomethylation, whereas bidirectional Vglut2 methylation differences at single CpGs were associated with ELS alone. Exposure to both ELS and ethanol, in the Acb, was associated with lower promoter and higher intronic Vglut3 methylation; and in the dStr, with higher and lower methylation in 26% and 43% of the analyzed Vglut1 CpGs, respectively. In the mPFC, lower Vglut2 methylation was observed upon ELS- or ethanol-only. The present findings suggest Vglut1-3 CpG-specific methylation signatures of ELS and ethanol drinking, underlying previously reported Vglut1-3 transcriptional differences in the mesocorticolimbic brain.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
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