title: Obesity is associated with a decrease in expression but not with the hypermethylation of thermogenesis-related genes in adipose tissues.
abstract: BACKGROUND
  Impaired thermogenesis can promote obesity. Therefore, the aim of this study was to investigate whether the expression of thermogenesis-related genes is altered in adipose tissues of obese individuals and whether excessive methylation of their promoters is involved in this phenomenon.
  
  
  METHODS
  The expression of genes encoding β adrenergic receptors (ADRBs), thyroid hormone receptors (THRs), 5'-iodothyronine deiodinases (DIOs), and uncoupling proteins (UCPs) was measured by real-time PCR in visceral and in subcutaneous adipose tissues of 58 obese (BMI >40 kg/m(2)) and 50 slim (BMI 20-24.9 kg/m(2)) individuals. The methylation status of these genes was studied by the methylation-sensitive digestion/real-time PCR method.
  
  
  RESULTS
  The expression of ADRB2, ADRB3, THRA, THRB, DIO2, UCP2 was significantly lower in the adipose tissues of obese patients than in tissues of normal-weight individuals (P < 0.00001). In the obese, the expression of ADRB2, ADRB3, DIO2 was lower in visceral adipose tissue than in subcutaneous adipose tissue (P = 0.008, P = 0.002, P = 0.001, respectively). However, the mean methylation of CpG islands of these genes was similar in tissues with their high and low expression, and there was no correlation between the level of expression and the level of methylation.
  
  
  CONCLUSIONS
  Decreased expression of thermogenesis-related genes in adipose tissues of obese patients might result in the reduced reactivity to both hormonal and adrenergic stimuli and therefore in a lower potential to activate thermogenesis.
authors.affiliation: Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland. akurylowicz@imdik.pan.pl.
authors.forename: Alina
authors.initials: A
authors.lastname: Kurylowicz
authors.affiliation: Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland. martajonas@imdik.pan.pl.
authors.forename: Marta
authors.initials: M
authors.lastname: Jonas
authors.affiliation: Department of General and Transplantation Surgery, Medical University of Warsaw, 59 Nowogrodzka Street, 02-005, Warsaw, Poland. wojciech.lisik@wum.edu.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Lisik
authors.affiliation: Department of General and Transplantation Surgery, Medical University of Warsaw, 59 Nowogrodzka Street, 02-005, Warsaw, Poland. morjon@poczta.onet.pl.
authors.forename: Maurycy
authors.initials: M
authors.lastname: Jonas
authors.affiliation: Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland. zwicik@imdik.pan.pl.
authors.forename: Zofia Agnieszka
authors.initials: ZA
authors.lastname: Wicik
authors.affiliation: Department of General and Transplantation Surgery, Medical University of Warsaw, 59 Nowogrodzka Street, 02-005, Warsaw, Poland. zbigniew-wierzbicki@wp.pl.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Wierzbicki
authors.affiliation: Department of General and Transplantation Surgery, Medical University of Warsaw, 59 Nowogrodzka Street, 02-005, Warsaw, Poland. andrzejchmura@geil.pl.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Chmura
authors.affiliation: Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland. mpuzianowska@wum.edu.pl.|Department of Geriatrics and Gerontology, Medical Centre of Postgraduate Education, 99 Marymoncka Street, 01-813, Warsaw, Poland. mpuzianowska@wum.edu.pl.
authors.forename: Monika
authors.initials: M
authors.lastname: Puzianowska-Kuznicka
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D015992:Body Mass Index; D002763:Cholecystectomy; D019175:DNA Methylation; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007453:Iodide Peroxidase / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D024101:Mitochondrial Proteins / Q000378:metabolism; D009765:Obesity / Q000378:metabolism* / Q000628:therapy*; D060888:Real-Time Polymerase Chain Reaction; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D011988:Receptors, Thyroid Hormone / Q000378:metabolism; D011795:Surveys and Questionnaires; D022722:Thermogenesis; D000071256:Uncoupling Protein 1; D055815:Young Adult
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; D011943:Receptors, Adrenergic, beta; D011988:Receptors, Thyroid Hormone; D000071256:Uncoupling Protein 1; D007453:Iodide Peroxidase