title: DNA methylation profiling in different phases of temporomandibular joint osteoarthritis in rats.
abstract: OBJECTIVE
  Temporomandibular joint osteoarthritis (TMJOA) is a complex disease with strong genetic and epigenetic components in its pathogenesis. The aim of this study was to evaluate DNA methylation in mandibular head cartilage in different phases of experimentally-induced TMJOA in rats.
  
  
  METHODS
  DNA methylation was evaluated using microarrays in the mandibular head cartilage of early, intermediate and late stage experimentally-induced TMJOA, and of the normal age-matched control groups. Genes with differentially methylated CpG sites were analyzed to reveal the over-represented gene ontologies and pathways at different stages, and were compared with published expression profiles to assess their overlappings. The DNA methylation patterns of the target genes were validated by methylated DNA immunoprecipitation qPCR in additional independent cartilage samples and mRNA levels were analyzed by real-time PCR.
  
  
  RESULTS
  We observed 9489 differentially methylated regions between the TMJOA and controls. A total of 440 consistently altered genes were revealed in all three stages; most (80%) were hypomethylated and many were associated with cell cycle regulation. We also detected different DNA methylation changes in early and late stage TMJOA (Rearly=0.68, Rlate=0.47), while the differences between age-matched healthy cartilage were subtle. Strong inverse changes between methylation status and mRNA levels were confirmed in Adamts5, Chad, Cldn11 and Tnf.
  
  
  CONCLUSIONS
  Our data reveals dynamic DNA methylation patterns during the progression of TMJOA, with a different host of genes and pathways. The changes of cartilage DNA methylation patterns might contribute to understand the etiologic mechanisms of TMJOA epigenetically.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing 100081, PR China.
authors.forename: Jia-Ling
authors.initials: JL
authors.lastname: Xiao
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing 100081, PR China. Electronic address: jhmeng@aliyun.com.
authors.forename: Juan-Hong
authors.initials: JH
authors.lastname: Meng
authors.affiliation: Center for Temporomandibular Joint Disorder and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, PR China. Electronic address: kqyehuagan@bjmu.edu.cn.
authors.forename: Ye-Hua
authors.initials: YH
authors.lastname: Gan
authors.affiliation: Department of Dermatology and Venereology, Peking University First Hospital, Beijing 100034, PR China.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Peking University School of Basic Medical Sciences, Beijing 100191, PR China.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Zhou
authors.affiliation: Center for Temporomandibular Joint Disorder and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing 100081, PR China.
authors.forename: Xu-Chen
authors.initials: XC
authors.lastname: Ma
mesh_terms: D000071116:ADAMTS5 Protein; D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000235:genetics; D057167:Claudins; D016172:DNA Fingerprinting; D019175:DNA Methylation; D004195:Disease Models, Animal; D018450:Disease Progression; D008297:Male; D008334:Mandible / Q000473:pathology; D053858:Metabolic Networks and Pathways; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010003:Osteoarthritis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D013704:Temporomandibular Joint / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D013705:Temporomandibular Joint Disorders / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
chemical_list: D057167:Claudins; C492353:Cldn11 protein, rat; D012333:RNA, Messenger; D000071116:ADAMTS5 Protein; C518696:Adamts5 protein, rat
keywords: Claudin11; DNA methylation; Osteoarthritis; Temporomandibular joint