Department of Pulmonary Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
Allergy. 2012 Jun;67(6):744-50. doi: 10.1111/j.1398-9995.2012.02825.x. Epub 2012 Apr 28.
IL-33 is clearly expressed in the airway of patients with asthma, but its role in asthma has not yet been fully understood. IL-17F is also involved in the pathogenesis of asthma. However, the regulatory mechanisms of IL-17F expression remain to be defined. To further indentify the role of IL-33 in asthma, we investigated the expression of IL-17F by IL-33 in bronchial epithelial cells and its signaling mechanisms.
Bronchial epithelial cells were stimulated with IL-33. The levels of IL-17F expression were analyzed using real-time PCR and ELISA. Next, the involvement of ST2, MAP kinases, and mitogen- and stress-activated protein kinase1 (MSK1) was determined by Western blot analyses. Various kinase inhibitors and anti-ST2 neutralizing Abs were added to the culture to identify the key signaling events leading to the expression of IL-17F, in conjunction with the use of short interfering RNAs (siRNAs) targeting MSK1.
IL-33 significantly induced IL-17F gene and protein expression. The receptor for IL-33, ST2, was expressed in bronchial epithelial cells. Among MAP kinases, IL-33 phosphorylated ERK1/2, but not p38MAPK and JNK. It was inhibited by the pretreatment of anti-ST2 neutralizing (blocking) Abs. MEK inhibitor significantly blocked IL-17F production. Moreover, IL-33 phosphorylated MSK1, and MEK inhibitor diminished its phosphorylation. Finally, MSK1 inhibitors and transfection of the siRNAs targeting MSK1 significantly blocked the IL-17F expression.
IL-33 induces IL-17F via ST2-ERK1/2-MSK1 signaling pathway in bronchial epithelial cells. These data suggest that the IL-33/IL-17F axis is involved in allergic airway inflammation and may be a novel therapeutic target.
IL-33 在哮喘患者的气道中明显表达，但它在哮喘中的作用尚未完全阐明。IL-17F 也参与哮喘的发病机制。然而，IL-17F 表达的调节机制仍有待确定。为了进一步明确 IL-33 在哮喘中的作用，我们研究了 IL-33 对支气管上皮细胞中 IL-17F 的表达及其信号机制。
用 IL-33 刺激支气管上皮细胞。采用实时 PCR 和 ELISA 分析 IL-17F 表达水平。然后，通过 Western blot 分析确定 ST2、MAP 激酶和丝裂原和应激激活蛋白激酶 1（MSK1）的参与。在培养物中加入各种激酶抑制剂和抗 ST2 中和 Ab，以确定导致 IL-17F 表达的关键信号事件，并结合使用针对 MSK1 的短干扰 RNA（siRNA）。
IL-33 显著诱导 IL-17F 基因和蛋白表达。IL-33 的受体 ST2 在支气管上皮细胞中表达。在 MAP 激酶中，IL-33 磷酸化 ERK1/2，但不磷酸化 p38MAPK 和 JNK。它被预处理的抗 ST2 中和（阻断）Ab 抑制。MEK 抑制剂显著阻断 IL-17F 的产生。此外，IL-33 磷酸化 MSK1，MEK 抑制剂减少其磷酸化。最后，MSK1 抑制剂和针对 MSK1 的 siRNA 转染显著阻断了 IL-17F 的表达。
IL-33 通过 ST2-ERK1/2-MSK1 信号通路诱导支气管上皮细胞中的 IL-17F。这些数据表明，IL-33/IL-17F 轴参与过敏气道炎症，可能是一种新的治疗靶点。
