Department of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Department of Respiratory Medicine, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China; Department of Respiratory Medicine, Affiliated Hospital of Hainan Medical University, Haikou, 570102, China; Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, 570102, China.
Respir Physiol Neurobiol. 2020 Oct;281:103496. doi: 10.1016/j.resp.2020.103496. Epub 2020 Jul 16.
Mucin 5AC (MUC5AC) is a highly O-glycosylated mucin secreted by human bronchial epithelial cells during pulmonary inflammatory diseases. T antigen, a component of the MUC5AC glycans, is the product of the O-glycosylation transferase T-synthase and its chaperone Cosmc. Since the expression of Cosmc is mediated by signaling pathways and inflammatory factors affecting mucin O-glycosylation, we analyzed the impact of neutrophil elastase (NE)-mediated Cosmc and T antigen expression in BEAS-2B cells derived from human bronchial epithelial cells. The expression of Cosmc and T antigen in human lung tissue was analyzed by immunohistochemistry. Cellular immunohistochemistry and western blot analysis demonstrated elevated expression of T antigen in BEAS-2B cells after NE stimulation. Altered Cosmc expression in BEAS-2B cells after NE stimulation was analyzed by confocal microscopy, western blot analysis and quantitative RT-PCR. To assess the biological implications of Cosmc function for T-synthase activity and T antigen synthesis after NE stimulation, BEAS-2B cells were transfected with shRNA to silence the expression of Cosmc. The changes in signaling pathways were analyzed by western blotting. The expression of Cosmc and T antigen increased in lung tissue exposed to chronic inflammation. The expression of Cosmc and T antigen increased in NE-stimulated BEAS-2B cells. NE induced increases in T antigen expression and T-synthase transferase activity in BEAS-2B cells expressing Cosmc, highlighting the importance of Cosmc in the relationship between NE and T antigen. Cosmc and phosphatidylinositol-3-kinase (PI3K) played important roles in the signaling pathway that stimulated hyperexpression of T antigen.
黏蛋白 5AC（MUC5AC）是一种高度 O-糖基化的黏蛋白，由人支气管上皮细胞在肺部炎症性疾病期间分泌。T 抗原是 MUC5AC 聚糖的成分之一，是 O-糖基转移酶 T-合成酶及其伴侣 Cosmc 的产物。由于 Cosmc 的表达受影响黏蛋白 O-糖基化的信号通路和炎症因子调节，我们分析了中性粒细胞弹性蛋白酶 (NE) 介导的 Cosmc 和 T 抗原在人支气管上皮细胞衍生的 BEAS-2B 细胞中的表达。通过免疫组织化学分析人肺组织中 Cosmc 和 T 抗原的表达。细胞免疫组织化学和 Western blot 分析表明，NE 刺激后 BEAS-2B 细胞中 T 抗原的表达增加。通过共聚焦显微镜、Western blot 分析和定量 RT-PCR 分析 NE 刺激后 BEAS-2B 细胞中 Cosmc 的表达变化。为了评估 Cosmc 功能对 T-合成酶活性和 T 抗原合成的生物学意义，我们用 shRNA 转染 BEAS-2B 细胞以沉默 Cosmc 的表达。通过 Western blot 分析来分析信号通路的变化。慢性炎症暴露的肺组织中 Cosmc 和 T 抗原的表达增加。NE 刺激的 BEAS-2B 细胞中 Cosmc 和 T 抗原的表达增加。NE 诱导 Cosmc 表达的增加和 T 抗原在表达 Cosmc 的 BEAS-2B 细胞中的 T-合成酶转移酶活性增加，突出了 Cosmc 在 NE 与 T 抗原之间关系中的重要性。Cosmc 和磷脂酰肌醇-3-激酶 (PI3K) 在刺激 T 抗原过度表达的信号通路中发挥重要作用。
