p38 mitogen-activated protein kinase-induced glucocorticoid receptor phosphorylation reduces its activity: Role in steroid-insensitive asthma
p38 mitogen-activated protein kinase-induced glucocorticoid receptor phosphorylation reduces its activity: Role in steroid-insensitive asthma
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DOI：
10.1067/mai.2002.122465
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发表时间：
2002-04-01
影响因子：
14.2
通讯作者：
Adcock, IM
中科院分区：
文献类型：
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作者：
Irusen, E;Matthews, JG;Adcock, IM
背景资料：虽然糖皮质激素是治疗慢性炎症性疾病（如哮喘）最有效的方法，但有些患者的反应很差。IL-2和IL-4联合应用可以改变糖皮质激素受体（GR）配体结合亲和力，调节糖皮质激素的功能。目的：我们试图证实一组激素依赖性哮喘患者GR配体结合亲和力的改变，并研究IL-2和IL-4改变GR配体结合亲和力的机制。我们使用地塞米松结合试验和GR和磷酸化活化转录因子2表达的Western印迹分析检测了健康受试者、轻度哮喘受试者和重度哮喘类固醇依赖受试者的PBMC。GR磷酸化后测定正磷酸盐标记和免疫沉淀和细胞因子的生产通过ELISA.Results：GR配体结合亲和力减少，但在细胞质中的类固醇依赖性哮喘患者相比，在健康受试者（解离常数，39.8 +/- 4.6与6.79 +/- 0.8 nmol/L）。这种配体结合亲和力的差异可以通过IL-2和IL-4共处理来模拟，并被p38丝裂原活化激酶（MAPK）抑制剂SB 203580阻断。如通过活化的转录因子2的磷酸化所示，IL-2和IL-4对p38 MAPK的活化导致GR磷酸化，并降低地塞米松对LPS刺激的GM-CSF释放的抑制。CD 2 + T细胞p38 MAPK磷酸化发生在丝氨酸残基上。地塞米松调节IL-10释放的能力也被IL-2和IL-4共处理抑制。结论：p38 MAPK抑制剂有可能逆转重度哮喘患者对糖皮质激素的不敏感性，重建糖皮质激素的有益作用。
Background: Although glucocorticoids are the most effective treatment for chronic inflammatory diseases, such as asthma, some patients show a poor response. IL-2 combined with IL-4 can alter glucocorticoid receptor (GR) ligand-binding affinity and modulate glueocorticoid function.Objective: We sought to confirm the altered ligand-binding affinity in a distinct group of steroid-dependent asthmatic subjects and examine the mechanism by which IL-2 and IL-4 modify the ligand-binding affinity of the GR.Methods: We examined PBMCs from healthy subjects, subjects with mild asthma, and steroid-dependent subjects with severe asthma using dexamethasone-binding assays and Western blot analysis of GR and phosphorylated activated transcription factor 2 expression. GR phosphorylation was measured after orthophosphate labeling and immunoprecipitation and cytokine production by means of ELISA.Results: GR ligand-binding affinity was reduced in the nucleus but not in the cytoplasm of steroid-dependent asthmatic subjects compared with that seen in healthy subjects (dissociation constant, 39.8 +/- 4.6 vs 6.79 +/- 0.8 nmol/L). This difference in ligand-binding affinity could be mimicked by IL-2 and IL-4 cotreatment and was blocked by the p38 mitogen-activated kinase (MAPK) inhibitor SB203580. Activation of p38 MAPK by IL-2 and IL-4, as shown by means of phosphorylation of activated transcription factor 2, resulted in GR phosphorylation and reduced dexamethasone repression of LPS-stimulated GM-CSF release. p38 MAPK phosphorylation of CD2+ T cells occurred on serine residues. The ability of dexamethasone to modulate IL-10 release was also inhibited by IL-2 and IL-4 cotreatment. These effects were also inhibited by SB203580.Conclusion: These data show that p38 MAPK inhibitors may have potential in reversing glucocorticoid insensitivity and reestablishing the beneficial effects of glucocorticoids in patients with severe asthma.