IL-1beta Induces Lysozyme Overexpression through a Mechanism Involving ERK/p38 Mitogen Activated Protein Kinase Activation in Human Airway Epithelial Cells

BACKGROUND AND OBJECTIVES: Lysozyme, a major serous component of airway epithelial secretions, plays an important role in airway defense. However, little is understood about the regulation of its expression and the associated signaling pathway. The object of this study is to investigate the regulation of lysozyme expression, the downstream signaling pathway of lysozyme expression, and the related protein kinases under inflammatory conditions using the IL-1beta, which acts as a significant cytokine in many airway inflammations. MATERIALS AND METHODS: After the IL-1beta treatment of normal human nasal epithelial cells (NHNE), lysozyme mRNA expression was determined by RT-PCR. Expressed levels of ERK/p38 kinase were determined by Western blot analysis. RESULTS: IL-1beta treated NHNEcells had over-expressed lysozyme compared to the control group. Activated ERK/p38 kinase level showed marked increment by treating NHNE with IL-1beta. Lysozyme expression and ERK/p38 kinase levels decreased when inhibitors of ERK/p38 MAP kinases were added to the IL-1beta treated cells. Finally, expression of lysozyme and activated level of ERK/p38 MAP kinases decreased in a dominant-negative cell line even when treated with IL-1beta. CONCLUSION: From these results, we concluded that IL-1beta induces over-expression of lysozyme via ERK/p38 MAP kinase signaling pathways in airway epithelial cells.

Expression and regulation of MUC8 & MUC5AC by various cytokines in normal human nasal epithelial cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Sinusitis is one of the most commonly reported diseases in the world. A network of inflammatory mediators is known to be involved in the pathogenesis of chronic sinusitis and nasal mucus secretion may also be under the control of an inflammatory mediator network. To date, 12 human mucin genes have been identified; however, the regulation of MUC8 has not yet been found out. In this study, we described the regulation of the MUC8 mRNA expression by inflammatory mediators and investigated its cellular location. MATERIALS AND METHOD: MUC8 mRNA and MUC5AC mRNA were detected in culture using passage-2 normal human nasal epithelial (NHNE) cells after the treatment with a mixture of following inflammatory mediators; TNF-alpha, IL-1beta, LPS, IL-4, PAF. The translocation of MUC8 mRNA from the nucleus to the cytoplasm was investigated by treating the inflammatory mediators with in situ hybridization. RESULTS: We found that a mixture of inflammatory mediators increased the MUC8 mRNA expression but decreased the MUC5AC mRNA expression in cultured normal human nasal epithelial cells. Among the inflammatory mediators, Interleukin-4 was responsible for the decrease in the MUC5AC mRNA expression and the MUC5AC mucin secretion. We also found that MUC8 mRNA resides in the nucleus of goblet cells and is transported into the cytoplasm following the treatment with inflammatory mediators. CONCLUSION: These results indicate that MUC8 may play an important role in the pathogenesis of mucus hypersecretion in chronic sinusitis.

Comparison of Mucin and Lysozyme Expression between Human in vivo Nasal Epithelial Cells and Cultured Nasal Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to compare the expression of mucin and lysozyme in passage-2 normal human nasal epithelial (NHNE) cells with those in human in vivo nasal epithelium and human tracheal RNA. MATERIALS AND METHODS: Cell lysates and total RNA from passage-2 NHNE cells, and human in vivo nasal epithelial cells were obtained. The amount of mucin and lysozyme protein was measured by immunoblotting. and qualitative RT-PCR was done to investigate the expression of mucin mRNAs and lysozyme mRNA. RESULTS: Passage-2 NHNE cells contained 16% of mucin and 76% of lysozyme when compared to the amount of intracellular mucin and lysozyme of normal in vivo nasal epithelial cells. MUC4, MUC5AC, MUC7, MUC8 and lysozyme mRNAs were expressed in passage-2 NHNE cells. However, MUC2 and MUC5B mRNAs were not expressed. CONCLUSION: Passage-2 NHNE cells contain enough amount of mucin and lysozyme protein and express most mRNAs of secretory genes which are known to be expressed in the human airway. Thus, we find passage-2 NHNE cells to be suitable for conducting studies on secretions in the human upper airway.

Secretory Differentiation of Serially Passaged Normal Human Nasal Epithelial (NHNE) Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to subculture normal human nasal epithelial (NHNE)cells without compromising their ability to differentiate into secretory and ciliated cells and to study the effect of retinoic acid (RA)on mucous and serous secretions in each passaged cells. MATERIALS AND METHOD: Freshly isolated nasal epithelial cells from normal inferior turbinates were subcultured repeatedly in serum-free medium on plastic tissue culture dishes. The subcultured cells were tested after every passage for secretory differentiation in air-liquid interface (ALI) cultures. The apical secretion of cultured NHNE cells was characterized by immunoblotting and Western blotting. RESULTS: Cultured NHNE cells secreted mucin and lysozyme. RA was essential for mucociliary and secretory differentiation. The epithelium became squamous and mucin secretion decreased when RA was deleted from the culture media. Cells from passage 1(P-1) through passage-2 (P-2) remained competent to differentiate into mucous and squamous cells when grown in air-liquid interface culture. CONCLUSION: P-2 NHNE cell cultures retained many important features of normal epithelium and were suitable for conducting many studies of upper airway cell biology with an expanded cell pool.