인간 기도 상피세포에서 IKK/IκBα/NF-κB p65 신호전달 경로를 경유한 호흡기 MUC5AC 뮤신 유전자의 발현에 미치는 올레아놀산의 영향

Effect of Oleanolic Acid on the Gene Expression of Pulmonary MUC5AC Mucin through IKK/IκBα/NF-κB p65 in Human Airway Epithelial Cells

In the present study, we investigated whether oleanolic acid, an anti-inflammatory natural product, significantly affects the phorbol 12-myristate 13-acetate (PMA)-induced gene expression of airway MUC5AC mucin. Confluent NCIH292 cells were pretreated with oleanolic acid for 30 min and then stimulated with PMA for 24 h or the indicated periods. The MUC5AC mucin mRNA expression was measured by RT-PCR. Production of MUC5AC mucin protein was measured by ELISA. To elucidate the action mechanism of oleanolic acid, effect of oleanolic acid on PMA-induced NF-B signaling pathway was investigated by western blot analysis. The results were as follows: (1) Oleanolic acid significantly inhibited the production of MUC5AC mucin protein and down-regulated the expression of MUC5AC mucin mRNA; (2) Oleanolic acid inhibited PMA-induced activation (phosphorylation) of inhibitory kappa B kinase (IKK), and thus phosphorylation and degradation of inhibitory kappa Ba (IB); (3) Oleanolic acid inhibited PMA-induced nuclear translocation of nuclear factor kappa B (NF-B) p65, led to the down-regulation of MUC5AC mucin gene expression in NCI-H292 cells. These results suggest that oleanolic acid can regulate the gene expression of mucin by acting on airway epithelial cells through regulation of NF-B signaling pathway.