Endoplasmic reticulum stress/XBP1 promotes airway mucin secretion under the influence of neutrophil elastase.
Endoplasmic reticulum stress/XBP1 promotes airway mucin secretion under the influence of neutrophil elastase.
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DOI：
10.3892/ijmm.2021.4914
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发表时间：
2021-05
影响因子：
5.4
通讯作者：
Cheng Z
中科院分区：
文献类型：
--
作者：
Xu X;Li Q;Li L;Zeng M;Zhou X;Cheng Z
内质网（Endoplasmic reticulum， ER）应激是气道上皮细胞对各种刺激的重要反应，也可能参与粘蛋白的分泌过程。本研究探讨内质网应激对人气道上皮细胞中性粒细胞弹性蛋白酶（NE）诱导的粘蛋白（MUC）5AC产生的影响。采用活性氧（ROS）抑制剂n -乙酰半胱氨酸（NAC）或内质网应激化学抑制剂4-苯基丁酸（4-PBA）对16hbe14 -气道上皮细胞进行培养和预处理，或分别用肌醇要求激酶1α (IRE1α)小干扰RNA （siRNA）或x- box结合蛋白1 (XBP1) siRNA转染细胞，然后用NE孵育。结果显示，NE增加了16hbe14o细胞中ROS的产生，并显著增加了内质网应激相关蛋白的水平，如葡萄糖调节蛋白78 （GRP78）、激活转录因子6 （ATF6）、磷酸化蛋白激酶r样内质网激酶（pPERK）和磷酸化(p)IRE1α。剪接的XBP1蛋白和mRNA水平也升高，MUC5AC蛋白水平显著升高。研究发现，ROS清除剂NAC和内质网应激抑制剂4-PBA可降低内质网应激相关蛋白的表达和MUC5AC的产生和分泌。进一步的分析表明，IRE1α和XBP1 sirna也会减弱MUC5AC的分泌，同时剪接的XBP1 mRNA表达也会下降。综上所述，这些结果表明NE通过促进16hbe14 -气道上皮细胞中ROS的产生来诱导内质网应激，从而通过IRE1α和XBP1信号通路导致MUC5AC蛋白的产生和分泌增加。
Endoplasmic reticulum (ER) stress is an important reaction of airway epithelial cells in response to various stimuli, and may also be involved in the mucin secretion process. In the present study, the effect of ER stress on neutrophil elastase (NE)-induced mucin (MUC)5AC production in human airway epithelial cells was explored. 16HBE14o-airway epithelial cells were cultured and pre-treated with the reactive oxygen species (ROS) inhibitor, N-acetylcysteine (NAC), or the ER stress chemical inhibitor, 4-phenylbutyric acid (4-PBA), or the cells were transfected with inositol-requiring kinase 1α (IRE1α) small interfering RNA (siRNA) or X-box-binding protein 1 (XBP1) siRNA, respectively, and subsequently incubated with NE. The results obtained revealed that NE increased ROS production in the 16HBE14o-cells, with marked increases in the levels of ER stress-associated proteins, such as glucose-regulated protein 78 (GRP78), activating transcription factor 6 (ATF6), phosphorylated protein kinase R-like endoplasmic reticulum kinase (pPERK) and phosphorylated (p)IRE1α. The protein and mRNA levels of spliced XBP1 were also increased, and the level of MUC5AC protein was notably increased. The ROS scavenger NAC and ER stress inhibitor 4-PBA were found to reduce ER stress-associated protein expression and MUC5AC production and secretion. Further analyses revealed that MUC5AC secretion was also attenuated by IRE1α and XBP1 siRNAs, accompanied by a decreased mRNA expression of spliced XBP1. Taken together, these results demonstrate that NE induces ER stress by promoting ROS production in 16HBE14o-airway epithelial cells, leading to increases in MUC5AC protein production and secretion via the IRE1α and XBP1 signaling pathways.