Ramu Sangeetha, Calvén Jenny, Michaeloudes Charalambos, Menzel Mandy, Akbarshahi Hamid, Chung Kian Fan, Uller Lena
Dept of Experimental Medical Science, Lund University, Lund, Sweden.
These authors contributed equally.
ERJ Open Res. 2020 Oct 5;6(4). doi: 10.1183/23120541.00147-2020. eCollection 2020 Oct.
Asthma exacerbations are commonly associated with rhinovirus (RV) infection. Interleukin-33 (IL-33) plays an important role during exacerbation by enhancing Type 2 inflammation. Recently we showed that RV infects bronchial smooth muscle cells (BSMCs) triggering production of interferons and IL-33. Here we compared levels of RV-induced IL-33 in BSMCs from healthy and asthmatic subjects, and explored the involvement of pattern-recognition receptors (PRRs) and downstream signalling pathways in IL-33 expression.
BSMCs from healthy and severe and non-severe asthmatic patients were infected with RV1B or stimulated with the PRR agonists poly(I:C) (Toll-like receptor 3 (TLR3)), imiquimod (TLR7) and poly(I:C)/LyoVec (retinoic acid-inducible gene 1 (RIG-I)/melanoma differentiation-associated protein 5 (MDA5)). Knockdown of TLR3, RIG-I and MDA5 was performed, and inhibitors targeting TBK1, nuclear factor-κB (NF-κB) and transforming growth factor (TGF)-β-activated kinase 1 (TAK1) were used. Gene and protein expression were assessed.
RV triggered IL-33 gene and protein expression in BSMCs. BSMCs from patients with non-severe asthma showed higher baseline and RV-induced IL-33 gene expression compared to cells from patients with severe asthma and healthy controls. Furthermore, RV-induced IL-33 expression in BSMCs from healthy and asthmatic individuals was attenuated by knockdown of TLR3. Inhibition of TAK1, but not NF-κB or TBK1, limited RV-induced IL-33. The cytokine secretion profile showed higher production of IL-33 in BSMCs from patients with non-severe asthma compared to healthy controls upon RV infection. In addition, BSMCs from patients with non-severe asthma had higher levels of RV-induced IL-8, TNF-α, IL-1β, IL-17A, IL-5 and IL-13.
RV infection caused higher levels of IL-33 and increased pro-inflammatory and Type 2 cytokine release in BSMCs from patients with non-severe asthma. RV-induced IL-33 expression was mainly regulated by TLR3 and downstream TAK1. These signalling molecules represent potential therapeutic targets for treating asthma exacerbations.
哮喘急性发作通常与鼻病毒（RV）感染有关。白细胞介素-33（IL-33）通过增强2型炎症在急性发作期间发挥重要作用。最近我们发现RV感染支气管平滑肌细胞（BSMCs）会触发干扰素和IL-33的产生。在此，我们比较了健康人和哮喘患者的BSMCs中RV诱导的IL-33水平，并探讨了模式识别受体（PRRs）和下游信号通路在IL-33表达中的作用。
用RV1B感染健康人、重度和非重度哮喘患者的BSMCs，或用PRR激动剂聚肌胞苷酸（poly(I:C)）（Toll样受体3（TLR3））、咪喹莫特（TLR7）和聚肌胞苷酸/脂质体（维甲酸诱导基因1（RIG-I）/黑色素瘤分化相关蛋白5（MDA5））刺激。对TLR3、RIG-I和MDA5进行敲低，并使用靶向TBK1、核因子-κB（NF-κB）和转化生长因子（TGF）-β激活激酶1（TAK1）的抑制剂。评估基因和蛋白表达。
RV触发了BSMCs中IL-33基因和蛋白的表达。与重度哮喘患者和健康对照者的细胞相比，非重度哮喘患者的BSMCs显示出更高的基线和RV诱导的IL-33基因表达。此外，通过敲低TLR3可减弱健康人和哮喘患者的BSMCs中RV诱导的IL-33表达。抑制TAK1而非NF-κB或TBK1可限制RV诱导的IL-33。细胞因子分泌谱显示，RV感染后，非重度哮喘患者的BSMCs中IL-33的产生高于健康对照者。此外，非重度哮喘患者的BSMCs中RV诱导的IL-8、肿瘤坏死因子-α、白细胞介素-1β、白细胞介素-17A、白细胞介素-5和白细胞介素-13水平更高。
RV感染导致非重度哮喘患者的BSMCs中IL-33水平升高，并增加促炎和2型细胞因子的释放。RV诱导的IL-33表达主要受TLR3和下游TAK1调节。这些信号分子代表了治疗哮喘急性发作的潜在治疗靶点。
