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.

粘蛋白 5AC (MUC5AC) 是一种高度 O-糖基化的粘蛋白，由人类支气管上皮细胞在肺部炎症性疾病期间分泌。T 抗原是 MUC5AC 聚糖的组成部分，是 O-糖基化转移酶 T-合酶及其分子伴侣 Cosmc 的产物。由于 Cosmc 的表达是由影响粘蛋白 O-糖基化的信号通路和炎症因子介导的，我们分析了中性粒细胞弹性蛋白酶 (NE) 介导的 Cosmc 和 T 抗原表达对源自人支气管上皮细胞的 BEAS-2B 细胞的影响。Cosmc和T抗原在人肺组织中的表达通过免疫组织化学分析。细胞免疫组织化学和蛋白质印迹分析表明 NE 刺激后 BEAS-2B 细胞中 T 抗原的表达升高。通过共聚焦显微镜、蛋白质印迹分析和定量 RT-PCR 分析了 NE 刺激后 BEAS-2B 细胞中改变的 Cosmc 表达。为了评估 NE 刺激后 Cosmc 功能对 T 合酶活性和 T 抗原合成的生物学意义，用 shRNA 转染 BEAS-2B 细胞以沉默 Cosmc 的表达。通过蛋白质印迹分析信号通路的变化。Cosmc 和 T 抗原在暴露于慢性炎症的肺组织中的表达增加。Cosmc 和 T 抗原的表达在 NE 刺激的 BEAS-2B 细胞中增加。NE 诱导表达 Cosmc 的 BEAS-2B 细胞中 T 抗原表达和 T 合酶转移酶活性增加，突出了 Cosmc 在 NE 和 T 抗原之间的关系中的重要性。