title: [Glycyrrhizin inhibits human neutrophil elastase-induced mucin 5AC overproduction in human bronchial epithelial cells].
abstract: OBJECTIVE
  To investigate the effect of glycyrrhizin (Gly) on human neutrophil elastase (HNE)- induced mucin (MUC) 5AC overproduction in human bronchial epithelial cells (16HBE), and the potential signaling pathway involved in this process.
  
  
  METHODS
  The cultured cells were divided into 3 groups: a control group, cultured in serum-free DMEM medium; an HNE group, pretreated with HNE alone; and a Gly group, incubated with HNE and Gly. After stimulation with a variety of Gly concentrations, the cytotoxicity was assessed by methyl thiazolyl tetrazolium method. The mRNA expressions of p38, nuclear factor κB (NF-κB) p65, inhibitory κBα (IκBα) and MUC5AC were detected by real-time PCR. The phosphorylation levels of p38 (p-p38), NF-κB p65 (p-NF-κB p65) and IκBα (p-IκBα) were measured by Western blot while the levels of MUC5AC protein were analyzed by emzyme-linked immunosorbent assay and immunofluorescence.
  
  
  RESULTS
  Compared with the control group, the expression levels of MUC5AC mRNA and protein in the HNE group were both significantly increased. There was a significant increase in p-p38 and p-NF-κB p65, while the production of IκBα was much lower than that in the control group. Gly significantly inhibited the increase of MUC5AC, p38 and NF-κB p65, but increased the activity of IκBα.
  
  
  CONCLUSIONS
  Glycyrrhizin can inhibit MUC5AC overproduction via p38-NF-κB p65/IκBα signaling pathway.
authors.affiliation: Department of Respiration, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
authors.forename: Qingrong
authors.initials: Q
authors.lastname: Xiao
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Zhou
mesh_terms: D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D004847:Epithelial Cells / Q000378:metabolism*; D019695:Glycyrrhizic Acid / Q000494:pharmacology*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D019272:Leukocyte Elastase / Q000378:metabolism*; D055271:Mucin 5AC / Q000096:biosynthesis*; D000072000:NF-KappaB Inhibitor alpha; D010766:Phosphorylation; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D051996:Transcription Factor RelA / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D020672:I-kappa B Proteins; D055271:Mucin 5AC; C000606204:NFKBIA protein, human; C498143:RELA protein, human; D051996:Transcription Factor RelA; D000072000:NF-KappaB Inhibitor alpha; D019695:Glycyrrhizic Acid; D048051:p38 Mitogen-Activated Protein Kinases; D019272:Leukocyte Elastase