Asian Sand Dust Up-Regulates MUC4 Expression in Human Upper Airway Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Asian sand dust (ASD) is a meteorological phenomenon that occurs in spring time in Korea. ASD is composed of various organic and inorganic materials, which induce airway inflammation. MUC4 is an important membrane-bound mucin gene in the human airway, and its expression is increased in pathologic proliferative lesions such as nasal polyps. However, the effect of ASD on MUC4 in human airway epithelial cells is unclear. Therefore, this study aimed to investigate the effect and signaling pathway of ASD on MUC4 expressions in human airway epithelial cells. METERIALS AND METHOD: The effect and signaling pathway of ASD on MUC4 expressions were investigated in NCI-H292 cells and in the primary cultures of human nasal epithelial cells using reverse transcription-polymerase chain reaction, real-time polymerase chain reaction, enzyme immunoassay, and immunoblot analysis with several specific inhibitors and small interfering ribonucleic acid (siRNA). RESULTS: ASD induced MUC4 expression and the activated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK). An ERK1/2 MAPK inhibitor and a p38 MAPK inhibitor inhibited the ASD-induced MUC4 expression. In addition, the knockdowns of ERK1, ERK2 and p38 MAPK by the respective siRNA blocked the ASD-induced MUC4 mRNA expression. ASD induced toll-like receptor 4 (TLR4) mRNA expression. The knockdown of TLR4 by TLR4 siRNA blocked the phosphorylation of ERK1/2 and p38 MAPK, and the ASD-induced MUC4 mRNA expression. CONCLUSION: These results show that ASD induces MUC4 expressions via TLR4-dependent ERK1/2 and p38 MAPK signaling pathway in human airway epithelial cells.

Effect of Betulinic Acid on MUC5AC and MUC5B Expression in Airway Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: MUC5AC and MUC5B are representative secretory mucin genes in the human airway, whose expressions are increased by a variety of inflammatory mediators. Betulinic acid, a naturally occurring pentacyclic triterpenoid, is known to have an anti-inflammatory property. However, the effects of betulinic acid on mucin secretion of airway epithelial cells still have not been reported. Therefore, in this study, the effect of betulinic acid on inflammatory mediators-induced MUC5AC and MUC5B expressions was investigated in human airway epithelial cells. SUBJECTS AND METHOD: In the mucin-producing human NCI-H292 airway epithelial cells, the effects of betulinic acid on interleukin-1beta (IL-1beta)-, lipopolysaccharide (LPS)-, and phorbol myristate acetate (PMA)-induced MUC5AC and MUC5B expressions were analyzed by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: Betulinic acid attenuated IL-1beta-, LPS-, and PMA-induced MUC5B mRNA and glycoprotein expression in NCI-H292 cells. On the other hand, betulinic acid did not attenuate IL-1beta-, and LPS-, but induced PMA-induced MUC5AC mRNA and glycoprotein expressions in NCI-H292 cells. CONCLUSION: These results suggest that betulinic acid attenuates IL-1beta-, LPS-, and PMA-induced MUC5B expression in the airway epithelial cells. Therefore, betulinic acid may modulate a control of mucus-hypersecretion in airway inflammatory diseases.

Roflumilast Attenuates MUC5AC and MUC5B Expression in Airway Epithelial Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Roflumilast, a selective inhibitor of phosphodiesterase type 4, has an anti-inflammatory property. It has been used in the treatment of chronic inflammatory airway diseases such as chronic obstructive pulmonary disease and asthma. However, the effect of roflumilast on mucus secretion in inflammatory airway epithelial cells has not been reported. Therefore, this study was aimed at investigating the effects of roflumilast on the inflammatory mediator-induced MUC5AC and MUC5B expression in human airway epithelial cells. MATERIALS AND METHOD: In human mucin-producing NCI-H292 airway epithelial cells and primary cultures of nasal epithelial cells, the effects of roflumilast on lipopolysaccharide (LPS)- and phorbl-12-myrsitate-13-acetate (PMA)-induced MUC5AC and MUC5B expression were analyzed by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: Roflumilast attenuated LPS-induced MUC5AC and MUC5B mRNA and glycoprotein expression in NCI-H292 cells. And roflumilast attenuated PMA-induced MUC5AC and MUC5B mRNA and glycoprotein expression in NCI-H292 cells. In addition, roflumilast attenuated LPS and PMA-induced MUC5AC and MUC5B mRNA expression in the primary cultures of nasal epithelial cells. CONCLUSION: These results suggest that roflumilast attenuates MUC5AC and MUC5B expressions in airway epithelial cells. Roflumilast may be a potentially ideal therapeutic agent for the control of mucus-hypersecretion in treating chronic inflammatory airway diseases.