title: Yin Yang 1 expression and localisation in quadriceps muscle in COPD.
abstract: BACKGROUND
  Yin Yang 1 (YY1) is a transcriptional repressor that inhibits muscle gene expression and myogenesis. YY1 has not previously been investigated in the skeletal muscle of patients with COPD. The aims of this study were to investigate YY1 expression and localisation in the quadriceps muscle of COPD patients compared to healthy age-matched controls, and examine the relationship between YY1 expression and localisation and quadriceps muscle fibre cross-sectional area (CSA) in COPD patients.
  
  
  METHODS
  15 COPD patients and 8 age-matched controls underwent lung and quadriceps function assessments and a percutaneous quadriceps biopsy. Quadriceps muscle fibre CSA and fibre proportions and YY1 localisation were determined by immunofluorescence. YY1 was immunoprecipitated from muscle and YY1 levels assessed by western blotting.
  
  
  RESULTS
  YY1 levels were inversely correlated with type IIx and type I fibre CSA in patients and controls, though YY1 levels were not significantly different between the groups. Nuclear localisation of YY1 was demonstrated in the patients but not in controls.
  
  
  CONCLUSIONS
  YY1 expression is associated with smaller quadriceps fibre CSA in COPD and nuclear localisation of YY1 was found in muscle of patients but not controls. Regulation of YY1 appears altered in COPD and may be implicated in COPD-related muscle atrophy.
authors.affiliation: NIHR Respiratory Biomedical Research Unit, Royal Brompton Hospital & National Heart and Lung Institute, Imperial College London, United Kingdom. s.sathyapala@imperial.ac.uk
authors.forename: Samantha Amanda
authors.initials: SA
authors.lastname: Natanek
authors.forename: Joanna
authors.initials: J
authors.lastname: Riddoch-Contreras
authors.forename: Gemma Sarah
authors.initials: GS
authors.lastname: Marsh
authors.forename: Nicholas Stephen
authors.initials: NS
authors.lastname: Hopkinson
authors.forename: William D-C
authors.initials: WD
authors.lastname: Man
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Michael Iain
authors.initials: MI
authors.lastname: Polkey
authors.forename: Paul Robert
authors.initials: PR
authors.lastname: Kemp
mesh_terms: D000368:Aged; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics* / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000737:chemistry / Q000378:metabolism*; D050986:YY1 Transcription Factor / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D050986:YY1 Transcription Factor