Molecular Neuropsychiatry Research Branch, NIH/NIDA Intramural Research Program, Baltimore, Maryland, United States of America.
PLoS One. 2012;7(3):e34236. doi: 10.1371/journal.pone.0034236. Epub 2012 Mar 28.
Methamphetamine (METH) addiction is associated with several neuropsychiatric symptoms. Little is known about the effects of METH on gene expression and epigenetic modifications in the rat nucleus accumbens (NAC). Our study investigated the effects of a non-toxic METH injection (20 mg/kg) on gene expression, histone acetylation, and the expression of the histone acetyltransferase (HAT), ATF2, and of the histone deacetylases (HDACs), HDAC1 and HDAC2, in that structure. Microarray analyses done at 1, 8, 16 and 24 hrs after the METH injection identified METH-induced changes in the expression of genes previously implicated in the acute and longterm effects of psychostimulants, including immediate early genes and corticotropin-releasing factor (Crf). In contrast, the METH injection caused time-dependent decreases in the expression of other genes including Npas4 and cholecystokinin (Cck). Pathway analyses showed that genes with altered expression participated in behavioral performance, cell-to-cell signaling, and regulation of gene expression. PCR analyses confirmed the changes in the expression of c-fos, fosB, Crf, Cck, and Npas4 transcripts. To determine if the METH injection caused post-translational changes in histone markers, we used western blot analyses and identified METH-mediated decreases in histone H3 acetylated at lysine 9 (H3K9ac) and lysine 18 (H3K18ac) in nuclear sub-fractions. In contrast, the METH injection caused time-dependent increases in acetylated H4K5 and H4K8. The changes in histone acetylation were accompanied by decreased expression of HDAC1 but increased expression of HDAC2 protein levels. The histone acetyltransferase, ATF2, showed significant METH-induced increased in protein expression. These results suggest that METH-induced alterations in global gene expression seen in rat NAC might be related, in part, to METH-induced changes in histone acetylation secondary to changes in HAT and HDAC expression. The causal role that HATs and HDACs might play in METH-induced gene expression needs to be investigated further.
甲基苯丙胺（METH）成瘾与多种神经精神症状有关。关于 METH 对大鼠伏隔核（NAC）中基因表达和表观遗传修饰的影响知之甚少。我们的研究调查了非毒性 METH 注射（20mg/kg）对该结构中基因表达、组蛋白乙酰化以及组蛋白乙酰转移酶（HAT）、ATF2 和组蛋白去乙酰化酶（HDACs）、HDAC1 和 HDAC2 表达的影响。METH 注射后 1、8、16 和 24 小时进行的微阵列分析确定了 METH 诱导的先前涉及精神兴奋剂的急性和长期作用的基因表达变化，包括即刻早期基因和促肾上腺皮质释放因子（Crf）。相比之下，METH 注射导致其他基因的表达随时间减少，包括 Npas4 和胆囊收缩素（Cck）。途径分析表明，表达改变的基因参与行为表现、细胞间信号传递和基因表达调控。PCR 分析证实了 c-fos、fosB、Crf、Cck 和 Npas4 转录物表达的变化。为了确定 METH 注射是否导致组蛋白标记物的翻译后变化，我们使用 Western blot 分析并鉴定了 METH 介导的核亚部分中赖氨酸 9（H3K9ac）和赖氨酸 18（H3K18ac）的组蛋白 H3 乙酰化减少。相比之下，METH 注射导致乙酰化 H4K5 和 H4K8 随时间增加。组蛋白乙酰化的变化伴随着 HDAC1 表达水平降低和 HDAC2 蛋白水平增加。组蛋白乙酰转移酶 ATF2 的蛋白表达显著增加。这些结果表明，大鼠 NAC 中观察到的 METH 诱导的整体基因表达改变可能部分与 METH 诱导的组蛋白乙酰化改变有关，这是由于 HAT 和 HDAC 表达的改变导致的。需要进一步研究 HAT 和 HDAC 在 METH 诱导基因表达中可能发挥的因果作用。
