Growing evidence suggests that interleukin (IL)-13, a Th2-type cytokine, plays a critical role in the development of bronchial hyper-responsiveness (BHR), an essential feature of asthma, although the underlying mechanisms remain unknown. In the present study, we investigated whether IL-13 directly affects airway smooth muscle (ASM) function. In murine tracheal rings, IL-13 (100 ng ml-1, 24 h) significantly increased both the carbachol- and KCl-induced maximal force generation without affecting ASM sensitivity. In cultured human ASM cells, IL-13 (50 ng ml-1, 24 h) also augmented cytosolic calcium levels to bradykinin, histamine and carbachol by 60, 35 and 26%, respectively. The present study demonstrates that IL-13 may promote BHR by directly modulating ASM contractility, an effect that may be due to enhanced G protein-coupled receptor (GPCR)-associated calcium signaling.
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机译：越来越多的证据表明，Th2型细胞因子白介素（IL）-13在支气管高反应性（BHR）（哮喘的基本特征）的发展中起着关键作用，尽管其潜在机制尚不清楚。在本研究中，我们调查了IL-13是否直接影响气道平滑肌（ASM）功能。在鼠气管环中，IL-13（100 ng ml-1，24 h）显着增加了卡巴胆碱和KCl诱导的最大力产生，而不会影响ASM敏感性。在培养的人ASM细胞中，IL-13（50 ng ml-1，24 h）也使缓激肽，组胺和卡巴胆碱的胞质钙水平分别增加了60％，35％和26％。本研究表明，IL-13可能通过直接调节ASM收缩力来促进BHR，这可能是由于增强的G蛋白偶联受体（GPCR）相关的钙信号传导所致。
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