Bae Chang Hoon, Na Hyung Gyun, Choi Yoon Seok, Song Si-Youn, Kim Yong-Dae
Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Daegu, Korea.
Regional Center for Respiratory Diseases, Yeungnam University Medical Center, Daegu, Korea.
Clin Exp Otorhinolaryngol. 2018 Jun;11(2):124-132. doi: 10.21053/ceo.2017.00493. Epub 2018 Jan 11.
Clusterin (CLU) is known as apolipoprotein J, and has three isoforms with different biological functions. CLU is associated with various diseases such as Alzheimer disease, atherosclerosis, and some malignancies. Recent studies report an association of CLU with inflammation and immune response in inflammatory airway diseases. However, the effect of CLU on mucin secretion of airway epithelial cells has not yet been understood. Therefore, the effect and brief signaling pathway of CLU on MUC5AC (as a major secreted mucin) expression were investigated in human airway epithelial cells.
In the tissues of nasal polyp and normal inferior turbinate, the presence of MUC5AC and CLU was investigated using immunohistochemical stain and Western blot analysis. In mucin-producing human NCI-H292 airway epithelial cells and primary cultures of normal nasal epithelial cells, the effect and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway of CLU on MUC5AC expression were investigated using immunohistochemical stain, reverse transcription-polymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and Western blot analysis.
In the nasal polyps, MUC5AC and CLU were abundantly present in the epithelium on immunohistochemical stain, and nuclear CLU (nCLU) was strongly detected on Western blot analysis. In human NCI-H292 airway epithelial cells or the primary cultures of normal nasal epithelial cells, recombinant nCLU increased MUC5AC expression, and significantly activated phosphorylation of NF-κB. And BAY 11-7085 (a specific NF-κB inhibitor) and knockdown of NF-κB by NF-κB siRNA (small interfering RNA) significantly attenuated recombinant nCLU-induced MUC5AC expression.
These results suggest that nCLU induces MUC5AC expression via the activation of NF-κB signaling pathway in human airway epithelial cells.
簇集素（CLU）亦称为载脂蛋白J，有三种具有不同生物学功能的异构体。CLU与多种疾病相关，如阿尔茨海默病、动脉粥样硬化和某些恶性肿瘤。近期研究报道了CLU与炎症性气道疾病中的炎症和免疫反应有关。然而，CLU对气道上皮细胞黏蛋白分泌的影响尚不清楚。因此，在人气道上皮细胞中研究了CLU对MUC5AC（作为主要分泌性黏蛋白）表达的影响及其简要信号通路。
在鼻息肉和正常下鼻甲组织中，采用免疫组织化学染色和蛋白质印迹分析检测MUC5AC和CLU的存在情况。在产生黏蛋白的人NCI-H292气道上皮细胞和正常鼻上皮细胞原代培养物中，采用免疫组织化学染色、逆转录-聚合酶链反应、实时聚合酶链反应、酶免疫测定和蛋白质印迹分析研究CLU对MUC5AC表达的影响及其核因子κB（NF-κB）信号通路。
在鼻息肉中，免疫组织化学染色显示上皮中大量存在MUC5AC和CLU，蛋白质印迹分析强烈检测到核CLU（nCLU）。在人NCI-H292气道上皮细胞或正常鼻上皮细胞原代培养物中，重组nCLU增加MUC5AC表达，并显著激活NF-κB的磷酸化。而BAY 11-7085（一种特异性NF-κB抑制剂）和NF-κB小干扰RNA（siRNA）敲低NF-κB可显著减弱重组nCLU诱导的MUC5AC表达。
这些结果表明，nCLU通过激活人气道上皮细胞中的NF-κB信号通路诱导MUC5AC表达。
