Gadd45b and N -Methyl- d -Aspartate Induced DNA Demethylation in Postmitotic Neurons

Abstract

Aim In nondividing neurons examine the role of Gadd45b in active 5-methylcytosine (5MC) and 5-hydroxymethylcytosine (5HMC) removal at a gene promoter highly implicated in mental illnesses and cognition, Bdnf. Materials & methods Mouse primary cortical neuronal cultures with and without Gadd45b siRNA transfection were treated with N-methyl-D-aspartate (NMDA). Expression changes of genes reportedly involved in DNA demethylation, Bdnf mRNA and protein and 5MC and 5HMC at Bdnf promoters were measured. Results Gadd45b siRNA transfection in neurons abolishes the NMDA-induced increase in Bdnf IXa mRNA and reductions in 5MC and 5HMC at the Bdnf IXa promoter. Conclusion These results contribute to our understanding of DNA demethylation mechanisms in neurons, and its role in regulating NMDA responsive genes implicated in mental illnesses.

Ethanol-induced changes in poly (ADP ribose) polymerase and neuronal developmental gene expression

“…MeDIP and hMeDIP were conducted as per our recent publications (Gavin et al, 2012; Gavin et al, 2015). Primary cortical neuronal culture samples were sonicated to 200–500 bp segments in SDS lysis buffer.…”

Role of Growth Arrest and DNA Damage‐Inducible, Beta in Alcohol‐Drinking Behaviors

“…GADD45b has been shown to be involved in demethylating the Bdnf9a promoter (Ma et al, 2009; Gavin et al, 2015). We measured 5-hydroxymethylcytosine (5HMC) and 5-methylcytosine (5MC) at the Bdnf9a promoter in C57 and DBA mice.…”

“…As perhaps a downstream consequence of lower NAc GADD45b and g we also found lower Bdnf9a mRNA expression in the NAc shell. GADD45b has been documented to play an important role in DNA demethylation at the Bdnf9a promoter, thereby having a positive modulatory function (Gavin et al, 2012; Ma et al, 2009; Gavin et al, 2015). In agreement with this reported role we found higher 5HMC and 5MC at the Bdnf9a promoter in the NAc of C57 mice as compared with DBA.…”

“…We also found that acute ethanol injection increased NAc histone acetylation and reduced 5HMC at the Bdnf gene in the NAc of C57 mice without producing any effects in DBA mice. We recently reported in primary neuron cultures 5HMC is highly responsive to exogenous stimuli (Gavin et al, 2015). Further, the ability of an HDAC inhibitor, in this case acute ethanol, to induce DNA demethylation has been previously documented (Detich et al, 2003; Dong et al, 2007).…”

“…MeDIP and hMeDIP were performed as previously published by our group (Gavin et al, 2015; Gavin et al, 2012). Tissue samples were sonicated to 200–500 bp segments in SDS lysis buffer.…”