Inhibition of TNF-α-induced MUC5AC mucin gene expression and production by wogonin through the inactivation of NF-κB signaling in airway epithelial cells.

In this study, we investigated whether wogonin significantly affects MUC5AC mucin gene expression and production in human airway epithelial cells. Confluent NCI-H292 cells were pretreated with wogonin for 30 min and then stimulated with tumor necrosis factor-α (TNF-α) for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by RT-PCR and ELISA, respectively. We found that incubation of NCI-H292 cells with wogonin significantly inhibited mucin production and down-regulated MUC5AC gene expression induced by TNF-α in a dose-dependent fashion. To elucidate the action mechanism of wogonin, effect of wogonin on TNF-α-induced NF-κB signaling pathway was investigated by western blot analysis. Wogonin inhibited NF-κB activation induced by TNF-α. Inhibition of IKK by wogonin led to the suppression of IκB phosphorylation and degradation, p65 nuclear translocation and NF-κB-regulated gene expression. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Wogonin also inhibited the gene products involved in cell survival (Bcl-2) and proliferation (cyclooxygenase-2). These results suggest that wogonin inhibits the NF-κB signaling pathway, which may explain its role in the inhibition of MUC5AC mucin gene expression and production.

Sikder MA ，Lee HJ ，Mia MZ ，Park SH ，Ryu J ，Kim JH ，Min SY ，Hong JH ，Seok JH ，Lee CJ ... -  《-》

Obtusifolin isolated from the seeds of Cassia obtusifolia regulates the gene expression and production of MUC5AC mucin in airway epithelial cells via affecting NF-κB pathway.

We investigated whether obtusin, obtusifolin, and cassiaside isolated from the seeds of Cassia obtusifolia inhibit the gene expression and production of airway mucin 5AC (MUC5AC). Confluent NCI-H292 cells were pretreated with obtusin, obtusifolin, or cassiaside for 30 min and then stimulated with epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA), or tumor necrosis factor-α (TNF-α) for 24 hr. The MUC5AC mucin gene expression was measured by reverse transcription-polymerase chain reaction. Production of MUC5AC mucin protein was measured by enzyme-linked immunosorbent assay. To elucidate the action mechanism of obtusifolin, effect of obtusifolin on PMA-induced nuclear factor kappa B (NF-κB) signaling pathway was investigated by western blot analysis. Obtusin, obtusifolin, or cassiaside inhibited the expression of MUC5AC mucin gene and the production of MUC5AC mucin protein, induced by EGF, PMA, or TNF-α. Obtusifolin inhibited PMA-induced activation (phosphorylation) of inhibitory kappa B kinase, and thus phosphorylation and degradation of inhibitory kappa B alpha. Obtusifolin inhibited PMA-induced nuclear translocation of NF-κB p65. These results suggest that obtusifolin can regulate the production and gene expression of mucin by acting on airway epithelial cells through regulation of NF-κB signaling pathway.

Choi BS ，Kim YJ ，Choi JS ，Lee HJ ，Lee CJ ... -  《-》

Verproside inhibits TNF-α-induced MUC5AC expression through suppression of the TNF-α/NF-κB pathway in human airway epithelial cells.

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of MUC5AC, are significant risk factors in asthma and chronic obstructive pulmonary disease (COPD) patients. Previously, we reported that verproside, a catalpol derivative iridoid glycoside isolated from Pseudolysimachion rotundum var. subintegrum, is a potent anti-asthmatic candidate drug in vivo. However, the molecular mechanisms underlying the pharmacological actions of verproside remain unknown. Here, we found that verproside significantly reduces the expression levels of tumor necrosis factor alpha (TNF-α)-induced MUC5AC mRNA and protein by inhibiting both nuclear factor kappa B (NF-κB) transcriptional activity and the phosphorylation of its upstream effectors such as IκB kinase (IKK)β, IκBα, and TGF-β-activated kinase 1 (TAK1) in NCI-H292 cells. Moreover, verproside attenuated TNF-α-induced MUC5AC transcription more effectively when combined with an IKK (BAY11-7082) or a TAK1 (5z-7-oxozeaenol) inhibitor than when administered alone. Importantly, we demonstrated that verproside negatively modulates the formation of the TNF-α-receptor (TNFR) 1 signaling complex [TNF-RSC; TNFR1-recruited TNFR1-associated death domain protein (TRADD), TNFR-associated factor 2 (TRAF2), receptor-interacting protein kinase 1 (RIP1), and TAK1], the most upstream signaling factor of NF-κB signaling. In silico molecular docking studies show that verproside binds between TRADD and TRAF2 subunits. Altogether, these results suggest that verproside could be a good therapeutic candidate for treatment of inflammatory airway diseases such as asthma and COPD by blocking the TNF-α/NF-κB signaling pathway.

Lee SU ，Sung MH ，Ryu HW ，Lee J ，Kim HS ，In HJ ，Ahn KS ，Lee HJ ，Lee HK ，Shin DH ，Lee Y ，Hong ST ，Oh SR ... -  《-》

Luteolin inhibited the gene expression, production and secretion of MUC5AC mucin via regulation of nuclear factor kappa B signaling pathway in human airway epithelial cells.

Luteolin, a flavonoidal compound derived from Lonicera japonica Thunb. and Chrysanthemum indicum L., has been reported to show anti-inflammatory, anti-oxidative and anti-carcinogenic effects. In this study, we investigated whether luteolin significantly affects the secretion, production and gene expression of airway mucin. Confluent NCI-H292 cells were pretreated with luteolin for 30 min and then stimulated with EGF (epidermal growth factor) or PMA (phorbol 12-myristate 13-acetate) for 24 h or the indicated periods. The MUC5AC mucin gene expression was measured by RT-PCR. Production and secretion of MUC5AC mucin protein were measured by ELISA. To elucidate the action mechanism of luteolin, effect of luteolin on PMA-induced NF-κB signaling pathway was investigated by western blot analysis. The results were as follows: (1) Luteolin inhibited the secretion of MUC5AC mucin protein induced by EGF or PMA; (2) Luteolin inhibited the production of MUC5AC mucin protein and the expression of MUC5AC mucin gene induced by EGF or PMA; (3) Luteolin inhibited PMA-induced phosphorylation and degradation of inhibitory kappa Bα (IκBα); (4) Luteolin inhibited PMA-induced phosphorylation and nuclear translocation of nuclear factor kappa B (NF-κB) p65. This result suggests that luteolin can regulate the secretion, production and gene expression of mucin by acting on airway epithelial cells via regulation of NF-kB signaling pathway.

Lee HJ ，Seo HS ，Ryu J ，Yoon YP ，Park SH ，Lee CJ ... -  《-》

Silibinin regulates gene expression, production and secretion of mucin from cultured airway epithelial cells.

We investigated whether silibinin significantly affects gene expression, production and secretion of mucin from cultured airway epithelial cells. Confluent NCI-H292 cells were pretreated with silibinin for 30 min and then stimulated with epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA) or TNF-α for 24 h. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The effect of silibinin on TNF-α-induced activation of NF-κB p65 was also examined. Confluent primary rat tracheal surface epithelial (RTSE) cells were pretreated with adenosine triphosphate (ATP) for 5 min and then treated for 30 min in the presence of silibinin to assess the effect on mucin secretion using ELISA. The results were as follows: (i) silibinin inhibited the expression of the MUC5AC mucin gene induced by EGF, PMA or TNF-α from NCI-H292 cells; (ii) silibinin also inhibited the production of MUC5AC mucin protein induced by the same inducers from NCI-H292 cells; (iii) silibinin inhibited the activation of NF-κB p65 by TNF-α in NCI-H292 cells; (iv) silibinin significantly decreased ATP-induced mucin secretion from cultured RTSE cells. This result suggests that silibinin can regulate gene expression, production and secretion of mucin by directly acting on airway epithelial cells.

Kim KD ，Lee HJ ，Lim SP ，Sikder A ，Lee SY ，Lee CJ ... -  《-》