Jayanthi Subramaniam, McCoy Michael T, Chen Billy, Britt Jonathan P, Kourrich Saїd, Yau Hau-Jie, Ladenheim Bruce, Krasnova Irina N, Bonci Antonello, Cadet Jean Lud
Molecular Neuropsychiatry Research Branch, US Department of Health and Human Services/National Institutes of Health/National Institute on Drug Abuse/Intramural Research Program, Baltimore, MD.
Synaptic Plasticity Section, US Department of Health and Human Services/National Institutes of Health/National Institute on Drug Abuse/Intramural Research Program, Baltimore, MD.
Biol Psychiatry. 2014 Jul 1;76(1):47-56. doi: 10.1016/j.biopsych.2013.09.034. Epub 2013 Oct 16.
Chronic methamphetamine (METH) exposure causes neuroadaptations at glutamatergic synapses.
To identify the METH-induced epigenetic underpinnings of these neuroadaptations, we injected increasing METH doses to rats for 2 weeks and measured striatal glutamate receptor expression. We then quantified the effects of METH exposure on histone acetylation. We also measured METH-induced changes in DNA methylation and DNA hydroxymethylation.
Chronic METH decreased transcript and protein expression of GluA1 and GluA2 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) and GluN1 N-methyl-D-aspartate receptor subunits. These changes were associated with altered electrophysiological glutamatergic responses in striatal neurons. Chromatin immunoprecipitation-polymerase chain reaction revealed that METH decreased enrichment of acetylated histone H4 on GluA1, GluA2, and GluN1 promoters. Methamphetamine exposure also increased repressor element-1 silencing transcription factor (REST) corepressor 1, methylated CpG binding protein 2, and histone deacetylase 2 enrichment, but not of sirtuin 1 or sirtuin 2, onto GluA1 and GluA2 gene sequences. Moreover, METH caused interactions of REST corepressor 1 and methylated CpG binding protein 2 with histone deacetylase 2 and of REST with histone deacetylase 1. Surprisingly, methylated DNA immunoprecipitation and hydroxymethylated DNA immunoprecipitation-polymerase chain reaction revealed METH-induced decreased enrichment of 5-methylcytosine and 5-hydroxymethylcytosine at GluA1 and GluA2 promoter sequences. Importantly, the histone deacetylase inhibitor, valproic acid, blocked METH-induced decreased expression of AMPAR and N-methyl-D-aspartate receptor subunits. Finally, valproic acid also attenuated METH-induced decrease H4K16Ac recruitment on AMPAR gene sequences.
These observations suggest that histone H4 hypoacetylation may be the main determinant of METH-induced decreased striatal glutamate receptor expression.
长期暴露于甲基苯丙胺（METH）会导致谷氨酸能突触发生神经适应性变化。
为了确定这些神经适应性变化的METH诱导的表观遗传学基础，我们给大鼠注射递增剂量的METH，持续2周，并测量纹状体谷氨酸受体的表达。然后我们量化了METH暴露对组蛋白乙酰化的影响。我们还测量了METH诱导的DNA甲基化和DNA羟甲基化的变化。
长期METH降低了α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体（AMPAR）的GluA1和GluA2亚基以及N-甲基-D-天冬氨酸受体亚基GluN1的转录本和蛋白表达。这些变化与纹状体神经元中电生理谷氨酸能反应的改变有关。染色质免疫沉淀-聚合酶链反应显示，METH降低了GluA1、GluA2和GluN1启动子上乙酰化组蛋白H4的富集。甲基苯丙胺暴露还增加了抑制元件-1沉默转录因子（REST）共抑制因子1、甲基化CpG结合蛋白2和组蛋白去乙酰化酶2在GluA基因序列上的富集，但未增加沉默调节蛋白1或沉默调节蛋白2的富集。此外，METH导致REST共抑制因子1和甲基化CpG结合蛋白2与组蛋白去乙酰化酶2相互作用，以及REST与组蛋白去乙酰化酶1相互作用。令人惊讶的是，甲基化DNA免疫沉淀和羟甲基化DNA免疫沉淀-聚合酶链反应显示，METH诱导GluA1和GluA2启动子序列上5-甲基胞嘧啶和5-羟甲基胞嘧啶的富集减少。重要的是，组蛋白去乙酰化酶抑制剂丙戊酸可阻断METH诱导的AMPAR和N-甲基-D-天冬氨酸受体亚基表达降低。最后，丙戊酸还减弱了METH诱导的AMPAR基因序列上H4K16Ac募集的减少。
这些观察结果表明，组蛋白H4低乙酰化可能是METH诱导纹状体谷氨酸受体表达降低的主要决定因素。
