重度哮喘患者气道上皮细胞Axl表达降低与嗜酸性炎症相关
2022/07/19
摘要
背景：气道上皮来源的细胞因子在哮喘中引发和延续2型炎症中是至关重要的。然而，对于这种上皮细胞驱动的炎症反应是如何被负调控的，认识仍然有限。我们之前报道过Axl受体酪氨酸激酶在气道上皮基底细胞中表达，并在确定其干细胞身份中起作用。然而，Axl是否以及如何调节气道2型炎症仍不清楚。
方法：我们采用免疫荧光染色法比较了非哮喘组、轻中度哮喘组和重度哮喘组气道上皮中Axl的表达。我们通过查询支气管活检中全球基因表达的公共数据库来证实这一结果。然后，我们用家尘螨提取物(HDM)鼻内处理野生型或Axl敲除小鼠，并对其气管内浸润的嗜酸性粒细胞数量进行定量。利用靶向Axl的siRNA进一步进行了基于细胞的分析，以识别参与Axl介导炎症调节的分子。
结果：组织学和转录组分析显示重度哮喘患者气道基底细胞中Axl蛋白和mRNA表达降低。重度哮喘患者Axl表达减少与嗜酸性粒细胞和肥大细胞浸润有关。重复HDM给药后，Axl敲除小鼠气管内嗜酸性粒细胞浸润更为明显。siRNA介导的Axl敲低提高了支气管上皮细胞中粒细胞巨噬细胞集落刺激因子(GM-CSF)的mRNA和蛋白表达。
结论：基底细胞表达的Axl激酶可能通过抑制气道GM-CSF抑制过度的嗜酸性炎症反应。Axl减少对严重哮喘的发病具有临床意义。
Decreased expression of airway epithelial Axl is associated with eosinophilic inflammation in severe asthma
Itakura K, Fujino N, Kamide Y, et al.
Abstract
BACKGROUND:Airway epithelium-derived cytokines are critical to provoke and perpetuate type 2 inflammation in asthma. Yet it is poorly understood how this epithelial cell-driven inflammatory response is negatively regulated. We previously reported that Axl receptor tyrosine kinase was expressed by basal cells in the airway epithelium and had a role in defining their stem cell identity. However, whether and how Axl regulates airway type 2 inflammation remains unknown.
METHODS:We performed immunofluorescence staining to compare Axl expression in airway epithelium between non-asthmatic subjects, mild-moderate asthma and severe asthma. We confirmed this result by interrogating public databases of global gene expression in endobronchial biopsies. We then quantified eosinophil numbers infiltrating into the trachea of wild-type or Axl-knockout mice that were intranasally treated with house dust mite extracts (HDM). Cell-based assays using siRNA targeting Axl were further performed to identify molecules involved in Axl-mediated regulation of inflammation.
RESULTS: Histological assessments and transcriptome analyses revealed decreases in protein and mRNA of Axl in airway basal cells of severe asthmatics. This reduction of Axl expression was correlated with infiltration of eosinophils and mast cells in severe asthmatics. Eosinophil infiltration was more evident in the trachea of Axl-knockout mice in response to repetitive HDM administration. siRNA-mediated knockdown of Axl increased mRNA and protein expression of granulocyte macrophage-colony stimulating factor (GM-CSF) in human bronchial epithelial cells.
CONCLUSIONS: Axl kinase expressed by basal cells may suppress excessive eosinophilic inflammation via inhibition of GM-CSF in the airway. Axl reduction has clinical implications for the pathogenesis of severe asthma.
背景：气道上皮来源的细胞因子在哮喘中引发和延续2型炎症中是至关重要的。然而，对于这种上皮细胞驱动的炎症反应是如何被负调控的，认识仍然有限。我们之前报道过Axl受体酪氨酸激酶在气道上皮基底细胞中表达，并在确定其干细胞身份中起作用。然而，Axl是否以及如何调节气道2型炎症仍不清楚。
方法：我们采用免疫荧光染色法比较了非哮喘组、轻中度哮喘组和重度哮喘组气道上皮中Axl的表达。我们通过查询支气管活检中全球基因表达的公共数据库来证实这一结果。然后，我们用家尘螨提取物(HDM)鼻内处理野生型或Axl敲除小鼠，并对其气管内浸润的嗜酸性粒细胞数量进行定量。利用靶向Axl的siRNA进一步进行了基于细胞的分析，以识别参与Axl介导炎症调节的分子。
结果：组织学和转录组分析显示重度哮喘患者气道基底细胞中Axl蛋白和mRNA表达降低。重度哮喘患者Axl表达减少与嗜酸性粒细胞和肥大细胞浸润有关。重复HDM给药后，Axl敲除小鼠气管内嗜酸性粒细胞浸润更为明显。siRNA介导的Axl敲低提高了支气管上皮细胞中粒细胞巨噬细胞集落刺激因子(GM-CSF)的mRNA和蛋白表达。
结论：基底细胞表达的Axl激酶可能通过抑制气道GM-CSF抑制过度的嗜酸性炎症反应。Axl减少对严重哮喘的发病具有临床意义。
（中日友好医院呼吸与危重症医学科 李春晓 摘译 林江涛 审校）
（Allergol Int, 2022, 71(3): 383-394. doi: 10.1016/j.alit.2022.02.010）
（Allergol Int, 2022, 71(3): 383-394. doi: 10.1016/j.alit.2022.02.010）
Decreased expression of airway epithelial Axl is associated with eosinophilic inflammation in severe asthma
Itakura K, Fujino N, Kamide Y, et al.
Abstract
BACKGROUND:Airway epithelium-derived cytokines are critical to provoke and perpetuate type 2 inflammation in asthma. Yet it is poorly understood how this epithelial cell-driven inflammatory response is negatively regulated. We previously reported that Axl receptor tyrosine kinase was expressed by basal cells in the airway epithelium and had a role in defining their stem cell identity. However, whether and how Axl regulates airway type 2 inflammation remains unknown.
METHODS:We performed immunofluorescence staining to compare Axl expression in airway epithelium between non-asthmatic subjects, mild-moderate asthma and severe asthma. We confirmed this result by interrogating public databases of global gene expression in endobronchial biopsies. We then quantified eosinophil numbers infiltrating into the trachea of wild-type or Axl-knockout mice that were intranasally treated with house dust mite extracts (HDM). Cell-based assays using siRNA targeting Axl were further performed to identify molecules involved in Axl-mediated regulation of inflammation.
RESULTS: Histological assessments and transcriptome analyses revealed decreases in protein and mRNA of Axl in airway basal cells of severe asthmatics. This reduction of Axl expression was correlated with infiltration of eosinophils and mast cells in severe asthmatics. Eosinophil infiltration was more evident in the trachea of Axl-knockout mice in response to repetitive HDM administration. siRNA-mediated knockdown of Axl increased mRNA and protein expression of granulocyte macrophage-colony stimulating factor (GM-CSF) in human bronchial epithelial cells.
CONCLUSIONS: Axl kinase expressed by basal cells may suppress excessive eosinophilic inflammation via inhibition of GM-CSF in the airway. Axl reduction has clinical implications for the pathogenesis of severe asthma.
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Liproxstatin-1通过抑制铁死亡减轻LPS/IL-13诱导的小鼠支气管上皮细胞损伤和中性粒细胞性哮喘
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