Ethanol deregulates Mecp2/MeCP2 in differentiating neural stem cells via interplay between 5-methylcytosine and 5-hydroxymethylcytosine at the Mecp2 regulatory elements

Abstract

Methyl CpG Binding Protein 2 (MeCP2) is an important epigenetic factor in the brain. MeCP2 expression is affected by different environmental insults including alcohol exposure. Accumulating evidence supports the role of aberrant MeCP2 expression in ethanol exposureinduced neurological symptoms. However, the underlying molecular mechanisms of ethanolinduced MeCP2 deregulation remain elusive. To study the effect of ethanol on Mecp2/MeCP2 expression during neurodifferentiation, we established an in vitro model of ethanol exposure, using differentiating embryonic brain-derived neural stem cells (NSC). Previously, we demonstrated the impact of DNA methylation at the Mecp2 regulatory elements (REs) on Mecp2/ MeCP2 expression in vitro and in vivo. Here, we studied whether altered DNA methylation at these REs is associated with the Mecp2/MeCP2 misexpression induced by ethanol. Binge-like and continuous ethanol exposure upregulated Mecp2/MeCP2, while ethanol withdrawal downregulated its expression. DNA methylation analysis by methylated DNA immunoprecipitation indicated that increased 5-hydroxymethylcytosine (5hmC) and decreased 5-methylcytosine (5mC) enrichment at specific REs were associated with upregulated Mecp2/MeCP2 following continuous ethanol exposure. The reduced Mecp2/MeCP2 expression upon ethanol withdrawal was associated with reduced 5hmC and increased 5mC enrichment at these REs. Moreover, ethanol altered global DNA methylation (5mC and 5hmC). Under the tested conditions, ethanol had minimal effects on Authors' contributionsVichithra R.B. Liyanage: Conception and design, collection and assembly of data, data analysis and interpretation, manuscript writing, and final approval of manuscript. Robby M. Zachariah: Conception and design, collection and assembly of data, and final approval of manuscript. James R. Davie: Scientific input, manuscript revisions, and final approval of manuscript. Mojgan Rastegar: Conception and design, contributed reagents/materials/analysis tools, data analysis and interpretation, manuscript writing, and final approval of manuscript. Conflict of interest statement

Interactions between Early Life Stress, Nucleus Accumbens MeCP2 Expression, and Methamphetamine Self-Administration in Male Rats

“…Given that the brain tissue in our previous study was collected more than 2 weeks following the last METH exposure, it is possible that the observed decrease in MeCP2 expression was due to METH withdrawal rather than METH intake per se. This effect is consistent with previous findings (Liyanage et al, 2015), and METH withdrawal has been shown to alter the expression of several transcription factors (Cadet et al, 2014). In the present study, tissue was collected immediately following SA, and we did not observe a difference in NAc core MeCP2 expression between the ELS-exposed rats and handled controls in the METH condition.…”

“…In order to investigate potential epigenetic mechanisms underlying ELS-induced increased vulnerability, we focused on striatal MeCP2 because of its established role in drug reward and reinforcement (Deng et al, 2010;Im et al, 2010;Zhang et al, 2014;Liyanage et al, 2015;Hou et al, 2015). The present study replicated our previous findings of ELS-induced increases in METH SA (Lewis et al, 2013;Lewis et al, 2015), which is also consistent with other drugs of abuse (Vazquez et al, 2005;Moffett et al, 2007).…”

“…Cocaine administration increases MeCP2 expression in multiple brain regions in rats (Cassel et al, 2006;Host et al, 2011;Im et al, 2010). In addition, continuous ethanol exposure upregulates MeCP2 expression, whereas ethanol withdrawal downregulates expression in vitro (Liyanage et al, 2015). In turn, manipulation of MeCP2 expression in the striatum and central amygdala alters both psychostimulant-and morphine-abuse-related behavior, respectively (Deng et al, 2010;Im et al, 2010;Zhang et al, 2014;Hou et al, 2015).…”

DNA cytosine hydroxymethylation levels are distinct among non-overlapping classes of peripheral blood leukocytes

“…1) in various classes of leukocytes. The binding and activity of MeCP2 appears enhanced at promoter 5hmCG sites in the brain (Zhubi et al, 2014) and its activity is considered particularly important, because in the brain MeCP2 activity responds to external stimuli (e.g., cocaine, ethanol) (Pol Bodetto et al, 2013; Liyanage et al, 2015). MeCP2 binding in the brain to modified C residues can work to enhance transcription if bound to 5hmCG, or repress transcription if bound to 5mCG (Mellen et al, 2012).…”

Bioinformatic Analysis of DNA Methylation in Neural Progenitor Cell Models of Alcohol Abuse

“…An article by Liyanage and colleagues (2015) attempted to shed light on the discrepancies between studies on the effects of ethanol on methyl CpG binding protein 2 (MeCP2) expression (Gangisetty et al 2014) while also understanding the molecular mechanisms of DNA methylation at regulatory elements in the MeCP2 gene. Ethanol-induced alterations of methylation can contribute to deregulating MeCP2 expression (Liyanage, Rastegar 2014).…”