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Apigenin Inhibits Tumor Necrosis Factor-α-Induced Production and Gene Expression of Mucin through Regulating Nuclear Factor-Kappa B Signaling Pathway in Airway Epithelial Cells.

Seo HS, Sikder MA, Lee HJ, Ryu J, Lee CJ - Biomol Ther (Seoul) (2014)

Bottom Line: Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells.To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis.Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1).

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, School of Medicine, Chungnam National University, Daejeon 301-131, Republic of Korea.

ABSTRACT
In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-α (TNF-α)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-α for 24 h or the indicated periods. 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), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-κB activation induced by TNF-α. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha (IκBα) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-κB signaling pathway in airway epithelial cells.

No MeSH data available.


Related in: MedlinePlus

Effect of apigenin on adaptor proteins of TNF receptor (TNFR) 1 signaling. NCI-H292 cells, either untreated or pretreated with 20 μM apigenin for 24 h, were treated with 25 ng/mL TNF-α for the indicated periods. Whole cell lysates were prepared and analyzed by western blotting using antibodies against RIP1, TRAF2 and TRADD. The results shown are representative of three independent experiments. Equal protein loading was evaluated by β-actin. *significantly different from TNF-α alone at each time point (p<0.05, Student’s t-test) (cont: control, Api: apigenin, TNF: TNF-α).
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f4-bt-22-525: Effect of apigenin on adaptor proteins of TNF receptor (TNFR) 1 signaling. NCI-H292 cells, either untreated or pretreated with 20 μM apigenin for 24 h, were treated with 25 ng/mL TNF-α for the indicated periods. Whole cell lysates were prepared and analyzed by western blotting using antibodies against RIP1, TRAF2 and TRADD. The results shown are representative of three independent experiments. Equal protein loading was evaluated by β-actin. *significantly different from TNF-α alone at each time point (p<0.05, Student’s t-test) (cont: control, Api: apigenin, TNF: TNF-α).

Mentions: Binding of TNF-α to TNFR1 induces receptor trimerization and recruitment of several downstream signaling proteins to their cytoplasmic domains (Hsu et al., 1995). TNFR1 interacts with the signaling protein TNFR1-associated death domain protein (TRADD), which recruits the adaptor protein, TNF receptor-associated factor 2 (TRAF2) (Hsu et al., 1996), receptor interacting protein (RIP1) (Stanger et al., 1995) and Fas associated protein with death domain (FADD) (Chinnaiyan et al., 1995). Subsequently, RIP1 is mainly polyubiquitinated and induces the recruitment to the TNFR1 and activation of IKK complex. For this reason, we investigated whether apigenin affects the adaptor protein expression of TNFR1 signaling pathway. As shown in Fig. 4, it was found that apigenin affected the expression of RIP1.


Apigenin Inhibits Tumor Necrosis Factor-α-Induced Production and Gene Expression of Mucin through Regulating Nuclear Factor-Kappa B Signaling Pathway in Airway Epithelial Cells.

Seo HS, Sikder MA, Lee HJ, Ryu J, Lee CJ - Biomol Ther (Seoul) (2014)

Effect of apigenin on adaptor proteins of TNF receptor (TNFR) 1 signaling. NCI-H292 cells, either untreated or pretreated with 20 μM apigenin for 24 h, were treated with 25 ng/mL TNF-α for the indicated periods. Whole cell lysates were prepared and analyzed by western blotting using antibodies against RIP1, TRAF2 and TRADD. The results shown are representative of three independent experiments. Equal protein loading was evaluated by β-actin. *significantly different from TNF-α alone at each time point (p<0.05, Student’s t-test) (cont: control, Api: apigenin, TNF: TNF-α).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256032&req=5

f4-bt-22-525: Effect of apigenin on adaptor proteins of TNF receptor (TNFR) 1 signaling. NCI-H292 cells, either untreated or pretreated with 20 μM apigenin for 24 h, were treated with 25 ng/mL TNF-α for the indicated periods. Whole cell lysates were prepared and analyzed by western blotting using antibodies against RIP1, TRAF2 and TRADD. The results shown are representative of three independent experiments. Equal protein loading was evaluated by β-actin. *significantly different from TNF-α alone at each time point (p<0.05, Student’s t-test) (cont: control, Api: apigenin, TNF: TNF-α).
Mentions: Binding of TNF-α to TNFR1 induces receptor trimerization and recruitment of several downstream signaling proteins to their cytoplasmic domains (Hsu et al., 1995). TNFR1 interacts with the signaling protein TNFR1-associated death domain protein (TRADD), which recruits the adaptor protein, TNF receptor-associated factor 2 (TRAF2) (Hsu et al., 1996), receptor interacting protein (RIP1) (Stanger et al., 1995) and Fas associated protein with death domain (FADD) (Chinnaiyan et al., 1995). Subsequently, RIP1 is mainly polyubiquitinated and induces the recruitment to the TNFR1 and activation of IKK complex. For this reason, we investigated whether apigenin affects the adaptor protein expression of TNFR1 signaling pathway. As shown in Fig. 4, it was found that apigenin affected the expression of RIP1.

Bottom Line: Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells.To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis.Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1).

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, School of Medicine, Chungnam National University, Daejeon 301-131, Republic of Korea.

ABSTRACT
In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-α (TNF-α)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-α for 24 h or the indicated periods. 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), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-κB activation induced by TNF-α. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha (IκBα) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-κB signaling pathway in airway epithelial cells.

No MeSH data available.


Related in: MedlinePlus