• Molecules and Cells
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• v.44 no.1
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• pp.38-49
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• 2021

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of the gel-forming MUC5AC protein, are significant risk factors for patients with asthma and chronic obstructive pulmonary disease (COPD). The transforming growth factor β (TGFβ) signaling pathway negatively regulates MUC5AC expression; however, the underlying molecular mechanism is not fully understood. Here, we showed that TGFβ significantly reduces the expression of MUC5AC mRNA and its protein in NCI-H292 cells, a human mucoepidermoid carcinoma cell line. This reduced MUC5AC expression was restored by a TGFβ receptor inhibitor (SB431542), but not by the inhibition of NF-κB (BAY11-7082 or Triptolide) or PI3K (LY294002) activities. TGFβ-activated Smad3 dose-dependently bound to MUC5AC promoter. Notably, TGFβ-activated Smad3 recruited HDAC2 and facilitated nuclear translocation of HDAC2, thereby inducing the deacetylation of NF-κB at K310, which is essential for a reduction in NF-κB transcriptional activity. Both TGFβ-induced nuclear translocation of Smad3/HDAC2 and deacetylation of NF-κB at K310 were suppressed by a Smad3 inhibitor (SIS3). These results suggest that the TGFβ-activated Smad3/HDAC2 complex is an essential negative regulator for MUC5AC expression and an epigenetic regulator for NF-κB acetylation. Therefore, these results collectively suggest that modulation of the TGFβ1/Smad3/HDAC2/NF-κB pathway axis can be a promising way to improve lung function as a treatment strategy for asthma and COPD.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1454-1463
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• 2023

Evaluating the antioxidant efficacy using Potentillae Chinensis Herba extract, the anti-inflammatory efficacy was tested in respiratory mucosal epithelium, RAW264.7 cells, and zebrafish. As a result, antioxidant activity increased in a concentration-dependent manner in DPPH free radical scavenging and ABTS+ cation radical activities. As a result of MTT assay for cell experiments, the survival rate of NCI-H292 cells was reduced to less than 70% when treated at each concentration of 100 ㎍/ml, subsequent experiments were conducted at 50 ㎍/ml. Anti-inflammatory efficacy evaluation, NO production, TNF-𝛼, IL-1𝛽, and PGE₂ decreased, and COX-2 also decreased significantly at 50 ㎍/ml. The mucin protein expression of Potentillae Chinensis Herba extract and bioconverted extract, it was observed that MUC5AC expression was significantly reduced. In the zebrafish toxicity evaluation, concentrations below 50 ㎍/ml did not show embryotoxicity and showed anti-inflammatory efficacy by reducing NO production due to LPS. The above results are valid to be valuable for use as a functional material that suppresses inflammation by helping the expression of Potentillae Chinensis Herba's respiratory mucus proteins.

• Tuberculosis and Respiratory Diseases
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• v.64 no.5
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• pp.347-355
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• 2008

Background: IPF is characterized by chronic, fibrosing inflammatory lung disease of unknown etiology. Typical symptoms of IPF are exertional dyspnea with nonproductive cough. Why patients with typical IPF have dry cough rather than productive cough, is unknown. IP-10 plays an important regulatory role in leukocyte trafficking into the lung. The present study investigated the effect of IP-10 in the pathogenesis of dry cough rather than productive cough in IPF patients. Methods: IP-10 concentration was measured by ELISA from BALF of IPF patients. To evaluate the role of IP-10 in mucin expression, the expression of the MUC5AC mucin gene was measured in NCI-H292 cells, a human pulmonary mucoepidermoid carcinoma cell line, after stimulation by TNF-${\alpha}$ with or without IP-10 pretreatment. EGFR-MAPK expression was also examined as a possible mechanism. Results: IP-10 levels were significantly higher in the BALF of IPF patients compared to healthy controls. IP-10 pretreatment reduced TNF-${\alpha}$ induced MUC5AC mucin expression by inhibiting the EGFR-MAPK signal transduction pathway in NCI-H292 cells. Conclusion: These findings suggest that little mucus production in IPF patients might be attributable to IP-10 overproduction, which inhibits the EGFR-MAPK signal transduction pathway required for MUC5AC mucin gene expression.