The effect of quercetin on human neutrophil elastase-induced mucin5AC expression in human airway epithelial cells

Division of Respiratory Medicine, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
International immunopharmacology (Impact Factor: 2.47). 07/2012; 14(2):195-201. DOI: 10.1016/j.intimp.2012.07.008
Source: PubMed


Quercetin, a plant flavonoid, is a potent antioxidant and anti-inflammatory agent. Mucus hypersecretion is a common pathological change in chronic inflammatory diseases of the airway. We investigated the effect of quercetin on mucin 5AC (MUC5AC) expression induced by human neutrophil elastase (HNE) in airway epithelial cells and its molecular mechanisms. Human airway epithelial (HBE16) cells were pretreated with quercetin and were treated with HNE. We found that HNE induced a significant increase in the levels of MUC5AC and EGFR in cells treated only with HNE. Quercetin suppressed gene transcription and protein expression of MUC5AC in a dose-dependent manner, with significant inhibition from 40 μM. mRNA and protein expressions of EGFR decreased markedly when pretreated with quercetin. Among three MAPK proteins, only phosphorylated ERK1/2 protein expression increased significantly after treatment with HNE alone and decreased significantly after pretreatment with quercetin. HNE also activated phosphorylated PKC protein expression which was attenuated when pretreated with quercetin. These results suggest that quercetin can inhibit HNE-induced MUC5AC expression in human airway epithelial cells through PKC/EGFR/ERK signal transduction pathway. In the future, quercetin might be a valuable treatment for mucin hypersecretion in chronic inflammatory airway diseases in clinic.

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    • "Several studies have also revealed its anti-inflammatory potential in airway pathologies that are usually associated with mucus hypersecretion. Using airway epithelial cells (HBE16), quercetin treatment was shown to reduce neutrophil elastase induced MUC5AC expression both at RNA and protein level through PKC/EGFR/ERK signal transduction pathway [130]. In addition, quercetin also attenuated IL-1b-induced MUC5AC expression by modulating ERK and p38 MAPK phosphorylation [131]. "
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    • "All of these effects are beneficial for the prevention and treatment of pulmonary diseases. Theaflavins, exocarpium citri grandis, Forsythia, breviscapine, naringenin, farrerol and quercetin are typical clinically used flavonoids and flavonoid-containing therapeutic agents (55–57). Due to their low costs and high availability from natural sources, these medicines have great potential for development as medicines for chronic inflammatory airway diseases. "
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