title: TLR4 Overexpression Inhibits Endothelial PAS Domain-Containing Protein 1 Expression in the Lower Respiratory Tract of Patients with Chronic COPD.
abstract: OBJECTIVE
  The study was designed to explore the potential relationship of TLR4 and endothelial PAS domain-containing protein 1 (EPAS1) in vivo and vitro experiments.
  
  
  METHODS
  Bronchoalveolar lavage fluid (BALF) samples were collected from 55 chronic obstructive pulmonary disease (COPD) patients and 25 healthy subjects. The differential cell count was performed using Wright-Giemsa staining. The expression levels of TLR4 and TLR5 were detected by RT-qPCR. The levels of methylation and mRNA expression of EPAS1 were assayed by bisulfite sequencing PCR and real-time PCR. The correlation of TLR4 and EPAS1 was also analyzed in TLR 4-overexpressing endothelial cells.
  
  
  RESULTS
  The results showed that the number of neutrophils, lymphocytes and macrophages and expression of TLR 4 were significantly increased in lower respiratory tract of COPD patients. Moreover, decreased EPAS1 mRNA and increased EPAS1 promoter methylation were detected in COPD, which were closely associated with increased TLR4 expression. According to in vitro experiments, TLR 4 inhibited EPAS1 mRNA expression and promoted promoter methylation in endothelial cells.
  
  
  CONCLUSIONS
  These findings suggest that TLR4 over-expression decreased EPAS1expression which contributes to the progress of COPD.
authors.affiliation: Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Yang
authors.forename: Fei-Yan
authors.initials: FY
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Ning
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Sun
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D015153:Blotting, Western; D002452:Cell Count; D019175:DNA Methylation; D005786:Gene Expression Regulation; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000378:metabolism; D012137:Respiratory System / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000235:genetics*; D051198:Toll-Like Receptor 5 / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D048051:p38 Mitogen-Activated Protein Kinases; D000099162:Endothelial PAS Domain-Containing Protein 1; C495346:TLR5 protein, human