Li Xiang, Yang Nan, Cheng Qi, Zhang Han, Liu Fen, Shang Yunxiao
Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, People's Republic of China.
J Asthma Allergy. 2021 May 18;14:513-524. doi: 10.2147/JAA.S307165. eCollection 2021.
Asthma is usually associated with airway inflammation and airway remodeling. Epithelial mesenchymal transition (EMT) often occurs in airway remodeling. The purpose of this study is to identify the effect of miR-21-5p and Smad7 signaling pathway in macrophage-derived exosomes on EMT of airway epithelial cells.
HE staining and Masson staining were used to verify the successful establishment of the asthma model. The levels of epithelial cell adhesion factor and stromal cell markers were detected by Western blot. The levels of miR-21-5p were detected by qRT-PCR. The expression of miR-21-5p in lung tissue was further verified by fluorescence in situ hybridization (FISH). Exosome morphology was observed by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Luciferase reporter assay was applied to analyze the interaction of miR-21-5p with Smad7.
The expression of miR-21-5p was upregulated in macrophages of rats in vivo with OVA-induced asthma. In vitro cultured alveolar macrophages stimulated by LPS could secrete exosomes with high levels of miR-21-5p. The exosome-derived miR-21-5p promotes EMT in rat tracheal epithelial cells through TGFβ1/Smad signaling pathway by downregulating Smad7. This process can be blocked by miR-21-5p inhibitor.
Rat alveolar macrophages produced high levels of miR-21-5p-containing exosomes, which transported miR-21-5p to tracheal epithelial cells, thus promoting EMT through TGF-β1/Smad signaling pathway by targeting Smad7.
哮喘通常与气道炎症和气道重塑相关。上皮-间质转化（EMT）常发生于气道重塑过程中。本研究旨在确定巨噬细胞来源的外泌体中miR-21-5p和Smad7信号通路对气道上皮细胞EMT的影响。
采用苏木精-伊红（HE）染色和Masson染色验证哮喘模型的成功建立。通过蛋白质免疫印迹法检测上皮细胞黏附因子和基质细胞标志物的水平。采用实时定量聚合酶链反应（qRT-PCR）检测miR-21-5p的水平。通过荧光原位杂交（FISH）进一步验证肺组织中miR-21-5p的表达。通过透射电子显微镜（TEM）和纳米颗粒跟踪分析（NTA）观察外泌体形态。应用荧光素酶报告基因检测法分析miR-21-5p与Smad7的相互作用。
在卵清蛋白（OVA）诱导的哮喘大鼠体内，巨噬细胞中miR-21-5p的表达上调。脂多糖（LPS）刺激体外培养的肺泡巨噬细胞可分泌高水平miR-21-5p的外泌体。外泌体来源的miR-21-5p通过下调Smad7，经转化生长因子β1（TGFβ1）/Smad信号通路促进大鼠气管上皮细胞的EMT。该过程可被miR-21-5p抑制剂阻断。
大鼠肺泡巨噬细胞产生高水平含miR-21-5p的外泌体，其将miR-21-5p转运至气管上皮细胞，从而通过靶向Smad7经TGF-β1/Smad信号通路促进EMT。
