Asthma Research Chair and Prince Naif Center for Immunology Research, King Saud University, Riyadh, Saudi Arabia.
J Clin Immunol. 2013 Feb;33(2):466-78. doi: 10.1007/s10875-012-9828-3. Epub 2012 Nov 16.
Most asthmatic patients have well controlled symptoms with regular treatment, but some require much higher doses of inhaled and oral corticosteroids, or in rare cases fail to respond; these patients may present Th-17 cell infiltration and associated cytokines (IL-17A and -F) in the airways, sputum and peripheral blood. Because glucocorticoid receptor-beta (GR-beta) is associated with corticosteroid resistance, we investigated whether Th-17 associated cytokines induce steroid insensitivity in PBMCs via GR-beta up-regulation.
GR-alpha, GR-beta, GILZ and IL-6 expression were analyzed in PBMCs stimulated with IL-2/IL-4, IL-17A/IL-17F and IL-23 cytokines by quantitative RT-PCR. Dexamethasone-inhibition of PHA-induced proliferation and Dexamethasone-induced apoptosis were determined by either (3)H-thymidine or CFSE-labelled cells and by Annexin-V staining and flow cytometry.
IL-17 and IL-23 cytokines significantly increased GR-beta expression. IL-2/IL-4 significantly decreased GR-alpha expression without affecting GR-beta. IL17, IL-23 and IL2 + 4 stimulations significantly hampered Dexamethasone-inhibition of proliferation (Dex EC(50) for: IL-17A + F = 251 nM; IL-23 = 435 nM; IL2 + 4 = 950 nM; Medium = 90 nM). IL2 + 4 and IL17A + F but not IL-23, significantly hampered Dexamethasone-induced apoptosis (1400 and 320 nM Dex, respectively). Dexamethasone's trans-activation of GILZ and trans-repression of NF-kB-driven IL-6 expression were both inhibited by IL2 + 4; IL17 + IL23 antagonized Dex trans-repression in PBMC from asthmatics.
GR-beta up-regulation by IL-17/IL-23 cytokines is associated with induced steroid insensitivity in PBMCs, observed as diminished Dexamethasone's effects on cell proliferation, apoptosis and gene regulation. Steroid resistance induced by IL-2/IL-4 was associated with decreased GR-alpha expression. This study supports the possibility that Th-17 lymphocytes and associated cytokines play a role in the mechanism of steroid hypo-responsiveness in severe asthmatics.
大多数哮喘患者通过常规治疗可有效控制症状，但部分患者需要使用更高剂量的吸入和口服皮质类固醇治疗，或极少数患者对治疗无反应；这些患者的气道、痰液和外周血中可能存在 Th-17 细胞浸润和相关细胞因子（IL-17A 和 -F）。由于糖皮质激素受体-β（GR-β）与皮质类固醇抵抗有关，我们研究了 Th-17 相关细胞因子是否通过 GR-β 上调诱导 PBMC 中的类固醇不敏感性。
通过定量 RT-PCR 分析 IL-2/IL-4、IL-17A/IL-17F 和 IL-23 细胞因子刺激 PBMC 后 GR-α、GR-β、GILZ 和 IL-6 的表达。通过（3）H-胸苷或 CFSE 标记细胞和 Annexin-V 染色和流式细胞术测定地塞米松抑制 PHA 诱导的增殖和地塞米松诱导的细胞凋亡。
IL-17 和 IL-23 细胞因子显著增加了 GR-β 的表达。IL-2/IL-4 显著降低了 GR-α 的表达而不影响 GR-β。IL17、IL-23 和 IL2+4 刺激显著阻碍了地塞米松抑制增殖（IL-17A+F 的 Dex EC（50）=251 nM；IL-23=435 nM；IL2+4=950 nM；培养基=90 nM）。IL2+4 和 IL17A+F 但不是 IL-23，显著阻碍了地塞米松诱导的细胞凋亡（分别为 1400 和 320 nM 地塞米松）。地塞米松对 GILZ 的转录激活和对 NF-kB 驱动的 IL-6 表达的转录抑制均被 IL2+4 抑制；IL17+IL23 拮抗了地塞米松对来自哮喘患者的 PBMC 的转录抑制。
IL-17/IL-23 细胞因子诱导的 GR-β 上调与 PBMC 中类固醇不敏感性有关，表现为地塞米松对细胞增殖、凋亡和基因调节的作用减弱。IL-2/IL-4 诱导的类固醇抵抗与 GR-α 表达减少有关。这项研究支持 Th-17 淋巴细胞及其相关细胞因子在严重哮喘患者类固醇低反应性机制中发挥作用的可能性。
