While IκB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its up-regulation by inflammatory cytokines remains under-explored. Since airway epithelial cells respond to airborne insults and potentiate inflammation, IKKε expression was characterized in pulmonary epithelial cell lines (A549, BEAS-2B) and primary human bronchial epithelial cells grown as submersion or differentiated air-liquid interface cultures. IKKε expression was up-regulated by the pro-inflammatory cytokines, interleukin-1β (IL-1β) and tumour necrosis factor-α (TNFα). Thus, mechanistic interrogations in A549 cells were used to demonstrate the NF-κB dependence of cytokine-induced IKKε. Furthermore, chromatin immunoprecipitation in A549 and BEAS-2B cells revealed robust recruitment of the NF-κB subunit, p65, to one 5' and two intronic regions within the IKKε locus (IKBKE). In addition, IL-1β and TNFα induced strong RNA polymerase 2 recruitment to the 5' region, the first intron, and the transcription start site. Stable transfection of the p65-binding regions into A549 cells revealed IL-1β- and TNFα-inducible reporter activity that required NF-κB, but was not repressed by glucocorticoid. While critical NF-κB motifs were identified in the 5' and downstream intronic regions, the first intronic region did not contain functional NF-κB motifs. Thus, IL-1β- and TNFα-induced IKKε expression involves three NF-κB-binding regions, containing multiple functional NF-κB motifs, and potentially other mechanisms of p65 binding through non-classical NF-κB binding motifs. By enhancing IKKε expression, IL-1β may prime, or potentiate, responses to alternative stimuli, as modelled by IKKε phosphorylation induced by phorbol 12-myristate 13-acetate. However, since IKKε expression was only partially repressed by glucocorticoid, IKKε-dependent responses could contribute to glucocorticoid-resistant disease.

中文翻译：

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IκB-激酶ε的诱导基因表达依赖于人肺上皮细胞中的核因子-κB。


虽然 IκB-激酶-ε (IKKε) 在病毒刺激后诱导免疫调节基因，但炎症细胞因子对它的上调作用仍未得到充分研究。由于气道上皮细胞对空气传播的损伤做出反应并加剧炎症，因此在肺上皮细胞系（A549、BEAS-2B）和作为浸没或分化的气液界面培养物生长的原代人支气管上皮细胞中对 IKKε 表达进行了表征。 IKKε 表达受到促炎细胞因子、白细胞介素-1β (IL-1β) 和肿瘤坏死因子-α (TNFα) 的上调。因此，A549 细胞中的机械询问被用来证明细胞因子诱导的 IKKε 的 NF-κB 依赖性。此外，A549 和 BEAS-2B 细胞中的染色质免疫沉淀显示 NF-κB 亚基 p65 被大量招募到 IKKε 位点 (IKBKE) 内的一个 5' 和两个内含子区域。此外，IL-1β 和 TNFα 诱导 RNA 聚合酶 2 强烈募集至 5' 区域、第一个内含子和转录起始位点。将 p65 结合区稳定转染到 A549 细胞中，揭示了 IL-1β 和 TNFα 诱导的报告活性需要 NF-κB，但不受糖皮质激素抑制。虽然在 5' 和下游内含子区域中鉴定出了关键的 NF-κB 基序，但第一个内含子区域不包含功能性 NF-κB 基序。因此，IL-1β和TNFα诱导的IKKε表达涉及三个NF-κB结合区，包含多个功能性NF-κB基序，以及通过非经典NF-κB结合基序进行p65结合的潜在其他机制。通过增强 IKKε 表达，IL-1β 可以引发或增强对替代刺激的反应，正如佛波醇 12-肉豆蔻酸酯 13-乙酸酯诱导的 IKKε 磷酸化所模拟的那样。 然而，由于糖皮质激素仅部分抑制 IKKε 表达，因此 IKKε 依赖性反应可能导致糖皮质激素耐药性疾病。