title: Ethanol induced acetylation of histone at G9a exon1 and G9a-mediated histone H3 dimethylation leads to neurodegeneration in neonatal mice.
abstract: The transient exposure of immature rodents to ethanol during postnatal day 7 (P7), comparable to a time point within the third trimester of human pregnancy, induces neurodegeneration. However, the molecular mechanisms underlying the deleterious effects of ethanol on the developing brain are poorly understood. In our previous study, we showed that a high dose administration of ethanol at P7 enhances G9a and leads to caspase-3-mediated degradation of dimethylated H3 on lysine 9 (H3K9me2). In this study, we investigated the potential role of epigenetic changes at G9a exon1, G9a-mediated H3 dimethylation on neurodegeneration and G9a-associated proteins in the P7 brain following exposure to a low dose of ethanol. We found that a low dose of ethanol induces mild neurodegeneration in P7 mice, enhances specific acetylation of H3 on lysine 14 (H3K14ace) at G9a exon1, G9a protein levels, augments the dimethylation of H3K9 and H3 lysine 27 (H3K27me2). However, neither dimethylated H3K9 nor K27 underwent degradation. Pharmacological inhibition of G9a activity prior to ethanol treatment prevented H3 dimethylation and neurodegeneration. Further, our immunoprecipitation data suggest that G9a directly associates with DNA methyltransferase (DNMT3A) and methyl-CpG-binding protein 2 (MeCP2). In addition, DNMT3A and MeCP2 protein levels were enhanced by a low dose of ethanol that was shown to induce mild neurodegeneration. Collectively, these epigenetic alterations lead to association of G9a, DNMT3A and MeCP2 to form a larger repressive complex and have a significant role in low-dose ethanol-induced neurodegeneration in the developing brain.
authors.affiliation: Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
authors.forename: S
authors.initials: S
authors.lastname: Subbanna
authors.affiliation: Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
authors.forename: N N
authors.initials: NN
authors.lastname: Nagre
authors.affiliation: Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
authors.forename: M
authors.initials: M
authors.lastname: Shivakumar
authors.affiliation: Vascular Biology Center, Georgia Regents University, Augusta, GA 30912, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Umapathy
authors.affiliation: Institute of Biosciences and Technology, Houston, Texas A&M University Health Science Center, Houston, TX 77030, USA.
authors.forename: D
authors.initials: D
authors.lastname: Psychoyos
authors.affiliation: Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; New York State Psychiatric Institute, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA. Electronic address: Basavaraj@nki.rfmh.org.
authors.forename: B S
authors.initials: BS
authors.lastname: Basavarajappa
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002492:Central Nervous System Depressants / Q000633:toxicity*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D000090205:DNA Methyltransferase 3A; D000431:Ethanol / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects; D011495:Histone-Lysine N-Methyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D051783:Methyl-CpG-Binding Protein 2 / Q000378:metabolism; D008745:Methylation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D019636:Neurodegenerative Diseases / Q000139:chemically induced* / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D002492:Central Nervous System Depressants; C000717967:DNMT3A protein, human; C000715535:Dnmt3a protein, mouse; D006657:Histones; C497393:Mecp2 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; D000431:Ethanol; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; C533711:G9a protein, mouse; D011495:Histone-Lysine N-Methyltransferase
keywords: ANOVA; BELs; CC3; ChIP; DNA methyltransferase; DNMT3A; FASD; G9a-related protein; GLP; H3K27me2; H3K9me2; IPs; MeCP2; analysis of variance; apoptosis; blood ethanol levels; cDNA; cTau; caspase 3-cleaved-tau; chromatin immunoprecipitation; cleaved caspase-3 (Asp175); complementary DNA; development; epigenetic; histone H3 lysine 27; histone H3 lysine 9; hprt; hypoxanthinephophoribosyltransferase; immunoprecipitates; methyl-CpG-binding protein 2; qPCR; quantitative real-time polymerase chain reaction