Cistrome-based Cooperation between Airway Epithelial Glucocorticoid Receptor and NF-κB Orchestrates Anti-inflammatory Effects
Cistrome-based Cooperation between Airway Epithelial Glucocorticoid Receptor and NF-κB Orchestrates Anti-inflammatory Effects
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DOI：
10.1074/jbc.m116.721217
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发表时间：
2016-06-10
影响因子：
4.8
通讯作者：
Gerber, Anthony N.
中科院分区：
文献类型：
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作者：
Kadiyala, Vineela;Sasse, Sarah K.;Gerber, Anthony N.
单体糖皮质激素受体（GR）对促炎性转录因子的拮抗作用长期以来被认为是糖皮质激素（GC）疗效的核心。然而，GC在哮喘等疾病中发挥治疗作用的机制和靶点仍不完全清楚。我们先前定义了GR和NF-κ B之间令人惊讶的协同相互作用，其增强了NF-κ B的有效抑制剂A20（TNFAIP 3）的表达。在这里，我们扩展了这一观察，以建立A20所需的最大细胞因子抑制GC。为了确定GR和NF-κ B合作的全球范围，我们使用染色质免疫沉淀法，然后进行深度测序，测定了经地塞米松、TNF或两者处理的气道上皮细胞中GR、NF-κ B的p65亚基和RNA聚合酶II的全基因组占有率。我们发现GR将p65募集到整个基因组的二聚体GR结合位点，并发现了GR-p65合作增强基因表达的其他调控元件。由这种机制调节的GR靶点包括关键的抗炎和损伤反应基因，如编码α 1抗胰蛋白酶的SERPINA 1和粘液产生抑制剂FOXP 4。虽然地塞米松治疗减少了RNA聚合酶II占用的TNF目标，如IL 8和TNFAIP 2，我们无法关联的GR或占用模式的抑制作用转录的特异性结合序列。我们的研究结果表明，GR和p65的协同抗炎基因调控有助于GC疗效，而GR和p65之间的相互作用并不普遍需要GC为基础的基因抑制。
Antagonism of pro-inflammatory transcription factors by monomeric glucocorticoid receptor (GR) has long been viewed as central to glucocorticoid (GC) efficacy. However, the mechanisms and targets through which GCs exert therapeutic effects in diseases such as asthma remain incompletely understood. We previously defined a surprising cooperative interaction between GR and NF-kappa B that enhanced expression of A20 (TNFAIP3), a potent inhibitor of NF-kappa B. Here we extend this observation to establish that A20 is required for maximal cytokine repression by GCs. To ascertain the global extent of GR and NF-kappa B cooperation, we determined genome-wide occupancy of GR, the p65 subunit of NF-kappa B, and RNA polymerase II in airway epithelial cells treated with dexamethasone, TNF, or both using chromatin immunoprecipitation followed by deep sequencing. We found that GR recruits p65 to dimeric GR binding sites across the genome and discovered additional regulatory elements in which GR-p65 cooperation augments gene expression. GR targets regulated by this mechanism include key anti-inflammatory and injury response genes such as SERPINA1, which encodes alpha 1 antitrypsin, and FOXP4, an inhibitor of mucus production. Although dexamethasone treatment reduced RNA polymerase II occupancy of TNF targets such as IL8 and TNFAIP2, we were unable to correlate specific binding sequences for GR or occupancy patterns with repressive effects on transcription. Our results suggest that cooperative anti-inflammatory gene regulation by GR and p65 contributes to GC efficacy, whereas tethering interactions between GR and p65 are not universally required for GC-based gene repression.