Environmental and Occupational Health Sciences Institute, Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA.
Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University Piscataway, NJ, USA.
Neuropharmacology. 2017 Oct;125:189-196. doi: 10.1016/j.neuropharm.2017.07.020. Epub 2017 Jul 22.
The dopamine transporter (DAT) is the key regulator of dopaminergic transmission and is a target of several xenobiotics, including pesticides and pharmacological agents. Previously, we identified a prominent role for histone deacetylases in the regulation of DAT expression. Here, we utilized a rat dopaminergic cell line (N27) to probe the responsiveness of DAT mRNA expression to inhibitors of histone acetylation. Inhibition of histone deacetylases (HDACs) by valproate, butyrate and Trichostatin A led to a 3-10-fold increase in DAT mRNA expression, a 50% increase in protein levels, which were accompanied by increased H3 acetylation levels. To confirm the mechanism of valproate-mediated increase in DAT mRNA, chromatin immunoprecipitation (ChIP) assays were used and demonstrated a significant increase in enrichment of acetylation of histone 3 on lysines 9 and 14 (H3K9/K14ac) in the DAT promoter. Expression of Nurr1 and Pitx3, key regulators of DAT expression, were increased following valproate treatment and Nurr1 binding was enriched in the DAT promoter. Together, these results indicate that histone acetylation and subsequent enhancement of transcription factor binding are plausible mechanisms for DAT regulation by valproate and, perhaps, by other xenobiotics.
多巴胺转运体（DAT）是多巴胺能传递的关键调节剂，也是包括农药和药理学制剂在内的几种外源化学物质的靶标。先前，我们发现组蛋白去乙酰化酶在 DAT 表达的调节中起着重要作用。在这里，我们利用大鼠多巴胺能细胞系（N27）来探究组蛋白乙酰化抑制剂对 DAT mRNA 表达的反应。丙戊酸钠、丁酸钠和 Trichostatin A 抑制组蛋白去乙酰化酶（HDACs）导致 DAT mRNA 表达增加 3-10 倍，蛋白水平增加 50%，同时伴随着 H3 乙酰化水平的增加。为了确认丙戊酸钠介导的 DAT mRNA 增加的机制，我们使用染色质免疫沉淀（ChIP）实验证明了 DAT 启动子上赖氨酸 9 和 14 上组蛋白 3 的乙酰化（H3K9/K14ac）的富集显著增加。丙戊酸钠处理后，Nurr1 和 Pitx3 的表达增加，DAT 启动子上的 Nurr1 结合增加。总之，这些结果表明组蛋白乙酰化和随后转录因子结合的增强是丙戊酸钠调节 DAT 的合理机制，也许是通过其他外源化学物质。
