BackgroundHistone deacetylase-3 (HDAC3) promotes neurodegeneration in various cell culture and in vivo models of neurodegeneration but the mechanism by which HDAC3 exerts neurotoxicity is not known. HDAC3 is known to be a transcriptional co-repressor. The goal of this study was to identify transcriptional targets of HDAC3 in an attempt to understand how it promotes neurodegeneration.ResultsWe used chromatin immunoprecipitation analysis coupled with deep sequencing (ChIP-Seq) to identify potential targets of HDAC3 in cerebellar granule neurons. One of the genes identified was the activity-dependent and neuroprotective transcription factor, Neuronal PAS Domain Protein 4 (Npas4). We confirmed using ChIP that in healthy neurons HDAC3 associates weakly with the Npas4 promoter, however, this association is robustly increased in neurons primed to die. We find that HDAC3 also associates differentially with the brain-derived neurotrophic factor (Bdnf) gene promoter, with higher association in dying neurons. In contrast, association of HDAC3 with the promoters of other neuroprotective genes, including those encoding c-Fos, FoxP1 and Stat3, was barely detectable in both healthy and dying neurons. Overexpression of HDAC3 leads to a suppression of Npas4 and Bdnf expression in cortical neurons and treatment with RGFP966, a chemical inhibitor of HDAC3, resulted in upregulation of their expression. Expression of HDAC3 also repressed Npas4 and Bdnf promoter activity.ConclusionOur results suggest that Bdnf and Npas4 are transcriptional targets of Hdac3-mediated repression. HDAC3 inhibitors have been shown to protect against behavioral deficits and neuronal loss in mouse models of neurodegeneration and it is possible that these inhibitors work by upregulating neuroprotective genes like Bdnf and Npas4.

中文翻译：

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Bdnf 和 Npas4 基因是 HDAC3 介导的转录抑制的目标

背景组蛋白去乙酰化酶 3 (HDAC3) 在各种细胞培养和体内神经变性模型中促进神经变性，但 HDAC3 发挥神经毒性的机制尚不清楚。已知 HDAC3 是一种转录共阻遏物。本研究的目的是确定 HDAC3 的转录靶点，试图了解它如何促进神经变性。结果我们使用染色质免疫沉淀分析结合深度测序 (ChIP-Seq) 来确定小脑颗粒神经元中 HDAC3 的潜在靶点。鉴定出的基因之一是活性依赖性和神经保护性转录因子，神经元 PAS 结构域蛋白 4 (Npas4)。我们使用 ChIP 证实，在健康神经元中，HDAC3 与 Npas4 启动子的关联较弱，但是，这种关联在准备死亡的神经元中显着增加。我们发现 HDAC3 还与脑源性神经营养因子 (Bdnf) 基因启动子存在差异，在垂死的神经元中具有更高的关联。相比之下，HDAC3 与其他神经保护基因的启动子（包括编码 c-Fos、FoxP1 和 Stat3 的基因）的关联，在健康和垂死的神经元中几乎检测不到。HDAC3 的过表达导致皮质神经元中 Npas4 和 Bdnf 表达的抑制，用 HDAC3 的化学抑制剂 RGFP966 处理导致它们表达的上调。HDAC3 的表达也抑制了 Npas4 和 Bdnf 启动子的活性。结论我们的结果表明 Bdnf 和 Npas4 是 Hdac3 介导的抑制的转录靶点。