title: Major histocompatibility complex class II transactivator inhibits cysteine-rich 61 expression in osteoblastic cells and its implication in the pathogenesis of periapical lesions.
abstract: BACKGROUND
  Osteoblastic expression of cysteine-rich 61 (Cyr61) correlates with the severity of periapical lesion-associated bone loss, but the regulatory mechanism of Cyr61 expression was not known.
  
  
  METHODS
  In the study we examined the effect of major histocompatibility complex class II transactivator (CIITA) on tumor necrosis factor (TNF)-alpha-induced Cyr61 synthesis in U2OS human osteoblastic cells by Western blot analysis. In a rat model of bacteria-induced apical periodontitis, we assessed the relation between osteoblastic expressions of CIITA/Cyr61 and disease progression by radiographic and immunohistochemistry studies.
  
  
  RESULTS
  We found that forced expression of CIITA suppressed Cyr61 synthesis in U2OS cells. In rat periapical lesions, osteoblastic CIITA decreased as the disease progressed, and expression of CIITA is negatively related to Cyr61 synthesis in osteoblasts.
  
  
  CONCLUSIONS
  Our data showed that CIITA is a repressor of Cyr61 synthesis in osteoblasts, and it might play a protective role in the pathogenesis of bone resorption in apical periodontitis, possibly through down-regulating the expression of Cyr61 in osteoblasts.
authors.affiliation: Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yuan-Ling
authors.initials: YL
authors.lastname: Lee
authors.forename: Sze-Kwan
authors.initials: SK
authors.lastname: Lin
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Hong
authors.forename: Juo-Song
authors.initials: JS
authors.lastname: Wang
authors.forename: Hsiang
authors.initials: H
authors.lastname: Yang
authors.forename: Eddie Hsiang-Hua
authors.initials: EH
authors.lastname: Lai
authors.forename: Mu-Hsiung
authors.initials: MH
authors.lastname: Chen
authors.forename: Sang-Heng
authors.initials: SH
authors.lastname: Kok
mesh_terms: D016301:Alveolar Bone Loss / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D055515:Cysteine-Rich Protein 61 / Q000037:antagonists & inhibitors* / Q000187:drug effects; D004195:Disease Models, Animal; D018450:Disease Progression; D004591:Electrophoresis, Polyacrylamide Gel; D005802:Genes, MHC Class II; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009687:Nuclear Proteins / Q000494:pharmacology*; D010006:Osteoblasts / Q000187:drug effects*; D010010:Osteoclasts / Q000473:pathology; D010485:Periapical Periodontitis / Q000382:microbiology / Q000503:physiopathology*; D019252:Radiography, Dental, Digital; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D015534:Trans-Activators / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D055515:Cysteine-Rich Protein 61; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha