Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada (C.F.R., M.O.A., M.M.M., S.V.S., D.Y., M.A.G., R.N.); Department of Zoology, Sohag University, Sohag, Egypt (M.O.A.); Department of Medicine, National Jewish Health, Denver, Colorado (S.S., A.N.G.); and Bioscience, Respiratory, Inflammation, and Autoimmunity, IMED Biotech Unit (M.L.M., C.K.-M.), and Respiratory GMed (A.M.-L.), AstraZeneca, Gothenburg, Molndal, Sweden.
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada (C.F.R., M.O.A., M.M.M., S.V.S., D.Y., M.A.G., R.N.); Department of Zoology, Sohag University, Sohag, Egypt (M.O.A.); Department of Medicine, National Jewish Health, Denver, Colorado (S.S., A.N.G.); and Bioscience, Respiratory, Inflammation, and Autoimmunity, IMED Biotech Unit (M.L.M., C.K.-M.), and Respiratory GMed (A.M.-L.), AstraZeneca, Gothenburg, Molndal, Sweden
Mol Pharmacol. 2018 Sep;94(3):1031-1046. doi: 10.1124/mol.118.112755. Epub 2018 Jun 29.
In asthma, the clinical efficacy of inhaled corticosteroids (ICSs) is enhanced by long-acting -adrenoceptor agonists (LABAs). ICSs, or more accurately, glucocorticoids, promote therapeutically relevant changes in gene expression, and, in primary human bronchial epithelial cells (pHBECs) and airway smooth muscle cells, this genomic effect can be enhanced by a LABA. Modeling this interaction in human bronchial airway epithelial BEAS-2B cells transfected with a 2× glucocorticoid response element (2×GRE)-driven luciferase reporter showed glucocorticoid-induced transcription to be enhanced 2- to 3-fold by LABA. This glucocorticoid receptor (GR; NR3C1)-dependent effect occurred rapidly, was insensitive to protein synthesis inhibition, and was maximal when glucocorticoid and LABA were added concurrently. The ability of LABA to enhance GR-mediated transcription was not associated with changes in GR expression, serine (Ser, Ser, Ser) phosphorylation, ligand affinity, or nuclear translocation. Chromatin immunoprecipitation demonstrated that glucocorticoid-induced recruitment of GR to the integrated 2×GRE reporter and multiple gene loci, whose mRNAs were unaffected or enhanced by LABA, was also unchanged by LABA. Transcriptomic analysis revealed glucocorticoid-induced mRNAs were variably enhanced, unaffected, or repressed by LABA. Thus, events leading to GR binding at target genes are not the primary explanation for how LABAs modulate GR-mediated transcription. As many glucocorticoid-induced genes are independently induced by LABA, gene-specific control by GR- and LABA-activated transcription factors may explain these observations. Because LABAs promote similar effects in pHBECs, therapeutic relevance is likely. These data illustrate the need to understand gene function(s), and the mechanisms leading to gene-specific induction, if existing ICS/LABA combination therapies are to be improved.
在哮喘中，长效β-肾上腺素能受体激动剂（LABA）增强吸入皮质类固醇（ICS）的临床疗效。ICS，或者更准确地说，糖皮质激素，促进治疗相关的基因表达变化，并且在原代人支气管上皮细胞（pHBECs）和气道平滑肌细胞中，这种基因组效应可以被 LABA 增强。在转染了 2×糖皮质激素反应元件（2×GRE）驱动的荧光素酶报告基因的人支气管气道上皮 BEAS-2B 细胞中模拟这种相互作用表明，LABA 增强了糖皮质激素诱导的转录，增强了 2-3 倍。这种糖皮质激素受体（GR；NR3C1）依赖性效应发生迅速，对蛋白质合成抑制不敏感，并且当糖皮质激素和 LABA 同时添加时达到最大值。LABA 增强 GR 介导的转录的能力与 GR 表达、丝氨酸（Ser、Ser、Ser）磷酸化、配体亲和力或核易位的变化无关。染色质免疫沉淀表明，糖皮质激素诱导的 GR 募集到整合的 2×GRE 报告基因和多个基因座，其 mRNA 不受 LABA 影响或增强，也不受 LABA 影响。转录组分析显示，糖皮质激素诱导的 mRNA 被 LABA 不同程度地增强、不受影响或抑制。因此，导致 GR 结合靶基因的事件不是 LABA 调节 GR 介导的转录的主要解释。由于许多糖皮质激素诱导的基因被 LABA 独立诱导，GR 和 LABA 激活的转录因子的基因特异性控制可能解释了这些观察结果。由于 LABAs 在 pHBECs 中也能促进类似的效应，因此具有治疗相关性。这些数据表明，如果要改进现有的 ICS/LABA 联合疗法，就需要了解基因功能和导致基因特异性诱导的机制。
