title: Effect of High Glucose on MUC5B expression in Human Airway Epithelial Cells.
abstract: OBJECTIVE
  Excessive production of mucus results in plugging of the airway tract, which can increase morbidity and mortality in affected patients. In patients with diabetes, inflammatory airway disease appears with more frequent relapse and longer duration of symptoms. However, the effects of high glucose (HG) on the secretion of mucin in inflammatory respiratory diseases are not clear. Therefore, this study was conducted in order to investigate the effect and the brief signaling pathway of HG on MUC5B expression in human airway epithelial cells.
  
  
  METHODS
  The effect and signaling pathway of HG on MUC5B expression were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with specific inhibitors and small interfering RNA.
  
  
  RESULTS
  HG increased MUC5B expression and epidermal growth factor receptor (EGFR) expression, and activated the phosphorylation of EGFR and p38 mitogen-activated protein kinase (MAPK). Pretreatment with EGFR inhibitor significantly attenuated the HG-induced phosphorylation of p38 MAPK, and pretreatments with p38 inhibitor or EGFR inhibitor significantly attenuated HG-induced MUC5B expression. In addition, knockdown of p38 MAPK by p38 MAPK siRNA significantly blocked HG-induced MUC5B expression.
  
  
  CONCLUSIONS
  These findings suggest that HG induces MUC5B expressionviathe sequential activations of the EGFR/p38 MAPK signaling pathway in human airway epithelial cells.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Sang Baik
authors.initials: SB
authors.lastname: Ye
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Yoon Seok
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Yo Han
authors.initials: YH
authors.lastname: Choi
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Bae
authors.affiliation: Department of Physiology, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Yong-Woon
authors.initials: YW
authors.lastname: Kim
authors.affiliation: Department of Physiology, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: So-Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.
authors.forename: Si-Youn
authors.initials: SY
authors.lastname: Song
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Yeungnam University College of Medicine, Gyeongsan, Korea.|Regional Center for Respiratory Diseases, Yeungnam University Medical Center, Daegu, Korea.
authors.forename: Yong-Dae
authors.initials: YD
authors.lastname: Kim
keywords: Epithelial Cell; Glucose; MUC5B Protein; Receptor, Epidermal Growth Factor; p38 Mitogen-Activated Protein Kinases