Emerging Role of One-Carbon Metabolism and DNA Methylation Enrichment on δ-Containing GABAA Receptor Expression in the Cerebellum of Subjects with Alcohol Use Disorders (AUD)
Emerging Role of One-Carbon Metabolism and DNA Methylation Enrichment on δ-Containing GABAA Receptor Expression in the Cerebellum of Subjects with Alcohol Use Disorders (AUD)
复制标题
DOI：
10.1093/ijnp/pyx075
复制
发表时间：
2017-12-01
影响因子：
4.8
通讯作者：
Guidotti, Alessandro
中科院分区：
文献类型：
--
作者：
Gatta, Eleonora;Auta, James;Guidotti, Alessandro
背景：小脑是大脑的一个区域，对急性和慢性饮酒的影响特别敏感。酒精暴露通过增加高尔基细胞向位于谷氨酸能颗粒细胞上的突触外含 α(6)/δ 的 GABA(A) 受体的 GABA 释放来减少小脑浦肯野细胞的输出。在这里，我们研究了长期饮酒是否会引起 GABA(A) 受体亚基表达的变化，以及这些变化是否与 DNA 甲基化引起的表观遗传机制的改变有关。 方法：我们使用了一组来自对照组和慢性酗酒者的死后小脑，这里定义为酒精使用障碍受试者（n = 25/组）。通过高效液相色谱法测定S-腺苷-甲硫氨酸/S-腺苷-高半胱氨酸。通过逆转录酶定量聚合酶链反应评估各种基因的mRNA水平。使用甲基化DNA免疫沉淀和羟甲基化DNA免疫沉淀测定评估启动子甲基化富集。结果：编码决定S-腺苷甲硫氨酸/S-腺苷同型半胱氨酸比率的1-碳代谢关键酶的mRNA增加，表明酒精使用障碍受试者的“甲基化指数”较高。我们发现，δ亚基 GABA(A) 受体启动子甲基化的增加与酒精使用障碍受试者小脑中 mRNA 和蛋白质水平的降低有关。含有 α(1) 或 α(6) 的 GABA(A) 受体亚基没有观察到变化。 DNA 甲基转移酶（1、3A 和 3B）的表达未改变，而参与 DNA 去甲基化途径的 TET1 的 mRNA 水平降低。因此，δ 亚基 GABA(A) 受体启动子甲基化的增加可能是由于酒精诱导的 DNA 去甲基化减少所致。结论： 总之，这些结果支持异常 DNA 甲基化途径可能参与酒精中毒小脑病理生理学的假设。此外，这项工作为DNA甲基化机制在酒精诱导的人类小脑GABA(A)受体功能的神经适应性变化中的核心作用提供了新的证据。
Background: Cerebellum is an area of the brain particularly sensitive to the effects of acute and chronic alcohol consumption. Alcohol exposure decreases cerebellar Purkinje cell output by increasing GABA release from Golgi cells onto extrasynaptic alpha(6)/delta-containing GABA(A) receptors located on glutamatergic granule cells. Here, we studied whether chronic alcohol consumption induces changes in GABA(A) receptor subunit expression and whether these changes are associated with alterations in epigenetic mechanisms via DNA methylation.Methods: We used a cohort of postmortem cerebellum from control and chronic alcoholics, here defined as alcohol use disorders subjects (n = 25/group). S-adenosyl-methionine/S-adenosyl-homocysteine were measured by high-performance liquid chromatography. mRNA levels of various genes were assessed by reverse transcriptase-quantitative polymerase chain reaction. Promoter methylation enrichment was assessed using methylated DNA immunoprecipitation and hydroxymethylated DNA immunoprecipitation assays.Results: mRNAs encoding key enzymes of 1-carbon metabolism that determine the S-adenosyl-methionine/S-adenosylhomocysteine ratio were increased, indicating higher "methylation index" in alcohol use disorder subjects. We found that increased methylation of the promoter of the delta subunit GABA(A) receptor was associated with reduced mRNA and protein levels in the cerebellum of alcohol use disorder subjects. No changes were observed in alpha(1)- or alpha(6)-containing GABA(A) receptor subunits. The expression of DNA-methyltransferases (1, 3A, and 3B) was unaltered, whereas the mRNA level of TET1, which participates in the DNA demethylation pathway, was decreased. Hence, increased methylation of the delta subunit GABA(A) receptor promoter may result from alcohol-induced reduction of DNA demethylation.Conclusion: Together, these results support the hypothesis that aberrant DNA methylation pathways may be involved in cerebellar pathophysiology of alcoholism. Furthermore, this work provides novel evidence for a central role of DNA methylation mechanisms in the alcohol-induced neuroadaptive changes of human cerebellar GABA(A) receptor function.