Acute activation of hippocampal glucocorticoid receptors results in different waves of gene expression throughout time
Acute activation of hippocampal glucocorticoid receptors results in different waves of gene expression throughout time
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DOI：
10.1111/j.1365-2826.2006.01413.x
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发表时间：
2006-04-01
影响因子：
3.2
通讯作者：
Datson, NA
中科院分区：
文献类型：
--
作者：
Morsink, MC;Steenbergen, PJ;Datson, NA
海马细胞功能的几个方面受到肾上腺分泌的糖皮质激素的延迟，基因组的方式。在此之前，我们使用基因表达系列分析来确定在固定时间点糖皮质激素受体（GR）诱导的海马转录变化。然而，由于mRNA水平的变化是短暂的，并且很可能先于对海马细胞功能的影响，因此本研究的目的是通过生成GR介导的基因表达变化的时间曲线来评估更宽时间窗内的转录变化。因此，我们使用从肾上腺切除大鼠获得的大鼠海马切片，在体内用低皮质酮颗粒替代，主要占据海马盐皮质激素受体。为了激活GR，在体外用高剂量（100 nM）的皮质酮处理切片，并在GR激活后1、3和5 h对基因表达进行分析。使用Affyssin基因芯片，观察到不同波的基因表达的惊人模式，从GR激活后1小时的完全下调的基因转移到GR激活后3小时的上调和下调的基因。5小时后，反应几乎恢复到基线。此外，实时定量聚合酶链反应用于验证选择的响应基因，包括参与神经传递和突触可塑性的基因，如促肾上腺皮质激素释放激素受体1，单胺氧化酶A，LIMK 1和钙调蛋白2。这允许确认18个选择的基因中的15个的GR响应性。总之，直接激活海马脑片中的GR导致基因表达的瞬时变化。基因表达被调节的模式表明，糖皮质激素的快速基因组效应可能是通过反式阻遏实现的，在反式激活的后期波之前。此外，我们确定了一些有趣的候选基因，这可能是糖皮质激素介导的海马细胞功能的影响。
Several aspects of hippocampal cell function are influenced by adrenal-secreted glucocorticoids in a delayed, genomic fashion. Previously, we used Serial Analysis of Gene Expression to identify glucocorticoid receptor (GR)-induced transcriptional changes in the hippocampus at a fixed time point. However, because changes in mRNA levels are transient and most likely precede the effects on hippocampal cell function, the aim of the current study was to assess the transcriptional changes in a broader time window by generating a time curve of GR-mediated gene expression changes. Therefore, we used rat hippocampal slices obtained from adrenalectomised rats, substituted in vivo with low corticosterone pellets, predominantly occupying the hippocampal mineralocorticoid receptors. To activate GR, slices were treated in vitro with a high (100 nM) dose of corticosterone and gene expression was profiled 1, 3 and 5 h after GR-activation. Using Affymetrix GeneChips, a striking pattern with different waves of gene expression was observed, shifting from exclusively down-regulated genes 1 h after GR-activation to both up and down regulated genes 3 h after GR-activation. After 5 h, the response was almost back to baseline. Additionally, real-time quantitative polymerase chain reaction was used for validation of a selection of responsive genes including genes involved in neurotransmission and synaptic plasticity such as the corticotropin releasing hormone receptor 1, monoamine oxidase A, LIMK1 and calmodulin 2. This permitted confirmation of GR-responsiveness of 15 out of 18 selected genes. In conclusion, direct activation of GR in hippocampal slices results in transient changes in gene expression. The pattern in which gene expression was modulated suggests that the fast genomic effects of glucocorticoids may be realised via transrepression, preceding a later wave of transactivation. Furthermore, we identified a number of interesting candidate genes which may underlie the glucocorticoid-mediated effects on hippocampal cell function.