title: Increased type II deiodinase protein in OA-affected cartilage and allelic imbalance of OA risk polymorphism rs225014 at DIO2 in human OA joint tissues.
abstract: OBJECTIVE
  Genetic variation at the type II deiodinase (D2) gene (DIO2) was previously identified as osteoarthritis (OA) risk factor. To investigate mechanisms possibly underlying this association, we assessed D2 protein in healthy and OA-affected cartilage and investigated allelic balance of the OA risk polymorphism rs225014 at DIO2 in human OA joints.
  
  
  METHODS
  Immunohistochemical staining of healthy and OA-affected cartilage was performed for D2. We then assessed allelic balance of DIO2 mRNA within OA-affected cartilage both at and away from the lesion, ligaments and subchondral bone. Allelic balance was measured by the amount of alleles 'C' and 'T' of the intragenic OA risk polymorphism rs225014 in heterozygous carriers.
  
  
  RESULTS
  A markedly higher amount of D2 positive cells and staining intensity was observed in OA cartilage. A significant, 1.3-fold higher presence was observed for the OA-associated rs225014 'C' allele relative to the 'T' allele of DIO2, which was significant in 28 of 31 donors.
  
  
  CONCLUSIONS
  In OA cartilage, D2 protein presence is increased. The allelic imbalance of the DIO2 mRNA transcript, with the OA risk allele 'C' of rs225014 more abundant than the wild-type 'T' allele in heterozygote carriers provides a possible mechanism by which genetic variation at DIO2 confers OA risk.
authors.affiliation: LUMC, Molecular Epidemiology, Einthovenweg 20, Leiden 2333 ZC, The Netherlands. s.bos@lumc.nl
authors.forename: Steffan D
authors.initials: SD
authors.lastname: Bos
authors.forename: Judith V M G
authors.initials: JV
authors.lastname: Bovée
authors.forename: Bouke J
authors.initials: BJ
authors.lastname: Duijnisveld
authors.forename: Emma V A
authors.initials: EV
authors.lastname: Raine
authors.forename: Wouter J
authors.initials: WJ
authors.lastname: van Dalen
authors.forename: Yolande F M
authors.initials: YF
authors.lastname: Ramos
authors.forename: Ruud
authors.initials: R
authors.lastname: van der Breggen
authors.forename: Rob G H H
authors.initials: RG
authors.lastname: Nelissen
authors.forename: P Eline
authors.initials: PE
authors.lastname: Slagboom
authors.forename: John
authors.initials: J
authors.lastname: Loughlin
authors.forename: Ingrid
authors.initials: I
authors.lastname: Meulenbelt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000201:enzymology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D007453:Iodide Peroxidase / Q000235:genetics* / Q000378:metabolism; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D020370:Osteoarthritis, Knee / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D012720:Severity of Illness Index; D000097564:Iodothyronine Deiodinase Type II
chemical_list: D007453:Iodide Peroxidase; D000097564:Iodothyronine Deiodinase Type II