背景:气道上皮屏障功能障碍已被证明有助于哮喘2型炎症的发展。白细胞介素(IL)-37是免疫应答和过敏性气道炎症的负调节因子。然而,IL-37是否对气道上皮屏障有影响尚不清楚.
方法:我们评估了IL-37在小鼠模型和培养的16HBE细胞中的作用。组织学和ELISA测定用于评估气道炎症。FITC-葡聚糖通透性测定用于评估气道上皮屏障功能。免疫荧光,采用westernblot和实时荧光定量PCR(RT-PCR)方法检测紧密连接蛋白的分布和表达。RT-PCR和Ca2荧光测量用于评估存储操作钙进入(SOCE)的mRNA表达和活性。
结果:与哮喘小鼠相比,IL-37抑制了屋尘螨(HDM)诱导的气道炎症,并降低了血清中IgE和支气管肺泡灌洗液(BALF)中2型细胞因子的水平。IL-37对HDM诱导的气道上皮屏障功能障碍具有保护作用,包括减少FITC-葡聚糖的泄漏,增强TJ蛋白的表达,并恢复了TJ蛋白的膜分布。此外,IL-37降低哮喘小鼠的BALF和HDM处理的16HBE细胞的上清液中IL-33的水平。IL-37降低了thapsigargin和HDM诱导的Ca2荧光峰值水平,并抑制Orai1的mRNA表达,提示IL-37对气道上皮细胞SOCE的抑制作用。
结论:IL-37通过抑制SOCE在气道炎症和HDM诱导的气道上皮屏障功能障碍中起保护作用。
BACKGROUND: Airway epithelial barrier dysfunction has been proved to contribute to the development of type 2 inflammation of asthma. Interleukin (IL)-37 is a negative regulator of immune responses and allergic airway inflammation. However, whether IL-37 has any effect on airway epithelial barrier has been unknown.
METHODS: We evaluated the role of IL-37 in both mouse model and cultured 16HBE cells. Histology and ELISA assays were used to evaluate airway inflammation. FITC-dextran permeability assay was used to evaluate the airway epithelial barrier function. Immunofluorescence, western blot and quantitative Real-Time PCR (RT-PCR) were used to evaluate the distribution and expression of tight junction proteins. RT-PCR and Ca2+ fluorescence measurement were used to evaluate the mRNA expression and activity of store-operated calcium entry (SOCE).
RESULTS: IL-37 inhibited house dust mite (HDM)-induced airway inflammation and decreased the levels of IgE in serum and type 2 cytokines in bronchoalveolar lavage fluid (BALF) compared to asthmatic mice. IL-37 protected against HDM-induced airway epithelial barrier dysfunction, including reduced leakage of FITC-dextran, enhanced expression of TJ proteins, and restored the membrane distribution of TJ proteins. Moreover, IL-37 decreased the level of IL-33 in the BALF of asthmatic mice and the supernatants of HDM-treated 16HBE cells. IL-37 decreased the peak level of Ca2+ fluorescence induced by thapsigargin and HDM, and inhibited the mRNA expression of Orai1, suggesting an inhibiting effect of IL-37 on SOCE in airway epithelial cells.
CONCLUSIONS: IL-37 plays a protective role in airway inflammation and HDM-induced airway epithelial barrier dysfunction by inhibiting SOCE.