Abstract：
Mycoplasma pneumoniae is the most common pathogen of respiratory tract infection in children and adults. Clinical observation shows that M. pneumoniae infection can cause massive mucus secretion in the respiratory tract, which makes the breathing of patients difficult. Studies have shown that M. pneumoniae infection can cause massive secretion of mucin 5AC (MUC5AC). Adhesin P1 plays an important role in the pathogenesis of M. pneumoniae infection by mediating the adhesion of pathogens to host cells, and the C-terminal residues of P1 (P1-C) are immunogenic. This study investigated the molecular mechanism of Wnt/β-catenin signaling pathway inhibitor Dickkopf-1 (DKK1) in the secretion of MUC5AC in mouse airway epithelial cells (MAECs) induced by P1-C. Scanning electron microscope and hematoxylin-eosin staining were used to observe the effect of P1-C on mucus secretion of MAECs. Protein chip was used to detect the secretion of cytokines and analyse the enrichment of related signaling pathways induced by P1-C in MAECs. Periodic acid schiff stain (PAS) staining, Tunel staining and Masson staining were used to detect the damage of the lungs of mouse exposed to P1-C. Immunohistochemistry was used to detect the secretion of MUC5AC expression, and Western blotting was used to reveal the molecular mechanism of DKK1-regulated secretion of MUC5AC induced by P1-C protein in MACES. The results showed that P1-C induced the massive secretion of mucus and inflammatory factors in MAECs. During P1-C infection, DKK1 down-regulated janus kinase 2 (JAK2), phosphorylation signaling and transcription activator 1 (p-STAT1) and phosphorylation signaling and activator of transcription 3 (p-STAT3) expression. Overexpression of DKK1 significantly up-regulated the expression of MUC5AC repressor transcription factor fork-head box protein A2 (FOXA2). At the same time, the expression of MUC5AC induced by P1-C was inhibited significantly. It is speculated that DKK1 can effectively reduce the secretion of MUC5AC in MAECs induced by P1-C by inhibiting the JAK/STAT1-STAT3 signaling pathway and up-regulating the expression of FOXA2.
摘要：
肺炎支原体是儿童和成人呼吸道感染最常见的病原体。临床观察表明肺炎支原体感染可引起呼吸道粘液大量分泌,这使得患者呼吸困难。研究表明,肺炎支原体感染可引起粘蛋白5AC(MUC5AC)的大量分泌。黏附素P1通过介导病原体与宿主细胞的粘附,在肺炎支原体感染的发病机制中发挥重要作用,并且P1(P1-C)的C末端残基具有免疫原性。本研究探讨了Wnt/β-catenin信号通路抑制剂Dickkopf-1(DKK1)在P1-C诱导的小鼠气道上皮细胞(MAECs)分泌MUC5AC的分子机制。扫描电子显微镜和苏木精-伊红染色观察P1-C对MAECs粘液分泌的影响。采用蛋白芯片检测MAECs中细胞因子的分泌情况,分析P1-C诱导的相关信号通路的富集情况。周期性酸性希夫染色（PAS）染色，Tunel染色和Masson染色用于检测暴露于P1-C的小鼠的肺损伤。免疫组化法检测MUC5AC的分泌表达,蛋白质印迹法揭示了DKK1调节MACES中P1-C蛋白诱导MUC5AC分泌的分子机制。结果表明，P1-C诱导MAECs中粘液和炎症因子的大量分泌。在P1-C感染期间，DKK1下调janus激酶2（JAK2），磷酸化信号和转录激活因子1(p-STAT1)和磷酸化信号和转录激活因子3(p-STAT3)表达。DKK1的过表达显著上调MUC5AC阻遏物转录因子叉头框蛋白A2(FOXA2)的表达。同时,P1-C诱导的MUC5AC表达受到显著抑制。推测DKK1可通过抑制JAK/STAT1-STAT3信号通路,上调FOXA2的表达,有效降低P1-C诱导的MAECs中MUC5AC的分泌。
