title: Simvastatin suppresses osteoblastic expression of Cyr61 and progression of apical periodontitis through enhancement of the transcription factor Forkhead/winged helix box protein O3a.
abstract: BACKGROUND
  In this study, the role of transcription factor Forkhead/winged helix box protein O3a (FoxO3a) in Cyr61 expression and its modulation by simvastatin were investigated in cultured murine osteoblasts and a rat model of induced apical periodontitis. We also examined the effects of simvastatin on the synthesis of chemokine CCL2 and chemotaxis of macrophages in vitro.
  
  
  METHODS
  We assessed tumor necrosis factor (TNF)-α-stimulated expression of Cyr61 and phosphorylated inactive FoxO3a (p-FoxO3a) in MC3T3-E1 murine osteoblasts by Western analysis. Forced expression of FoxO3a by lentiviral-based gene transduction was performed, and its effect on Cyr61 expression was evaluated. The modulation of CCL2 secretion and macrophage chemotaxis by simvastatin were examined by enzyme-linked immunosorbent assay and transwell migration assay, respectively. In a rat model of induced apical periodontitis, the relation between disease progression and osteoblastic expression of Cyr61, p-FoxO3a, and CCL2 and macrophage recruitment were studied by radiographic and immunohistochemistry analyses.
  
  
  RESULTS
  Western blot analysis showed enhanced expression of Cyr61 and p-FoxO3a after TNF-α treatment in a time-dependent manner. Simvastatin significantly counteracted the actions of TNF-α. Forced expression of FoxO3a reduced TNF-α-stimulated Cyr61 synthesis. Simvastatin and FoxO3a diminished TNF-α-induced CCL2 secretion and macrophage recruitment, whereas Cyr61 partially restored the stimulating action. In rat periapical lesions, simvastatin significantly attenuated bone resorption, reduced osteoblastic expressions of Cyr61, p-FoxO3a, and CCL2, and suppressed macrophage recruitment.
  
  
  CONCLUSIONS
  Simvastatin may alleviate periapical lesions by enhancing FoxO3a activity to suppress the synthesis of Cyr61 in osteoblasts. Moreover, the downstream effector mechanism of Cyr61 may involve CCL2 production and macrophage recruitment.
authors.affiliation: School of Dentistry, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Li-Deh
authors.initials: LD
authors.lastname: Lin
authors.forename: Sze-Kwan
authors.initials: SK
authors.lastname: Lin
authors.forename: Yueh-Ling
authors.initials: YL
authors.lastname: Chao
authors.forename: Sang-Heng
authors.initials: SH
authors.lastname: Kok
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Hong
authors.forename: Kuo-Liang
authors.initials: KL
authors.lastname: Hou
authors.forename: Eddie Hsiang-Hua
authors.initials: EH
authors.lastname: Lai
authors.forename: Hsiang
authors.initials: H
authors.lastname: Yang
authors.forename: Ming-Shu
authors.initials: MS
authors.lastname: Lee
authors.forename: Juo-Song
authors.initials: JS
authors.lastname: Wang
mesh_terms: D016475:3T3 Cells; D016301:Alveolar Bone Loss / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D002460:Cell Line; D018932:Chemokine CCL2 / Q000187:drug effects; D002633:Chemotaxis / Q000187:drug effects; D055515:Cysteine-Rich Protein 61 / Q000037:antagonists & inhibitors*; D004195:Disease Models, Animal; D018450:Disease Progression; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000187:drug effects*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000473:pathology; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000473:pathology; D010485:Periapical Periodontitis / Q000473:pathology / Q000503:physiopathology*; D019252:Radiography, Dental, Digital; D051381:Rats; D017207:Rats, Sprague-Dawley; D019821:Simvastatin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: C491850:CCN1 protein, mouse; C501849:CCN1 protein, rat; D018932:Chemokine CCL2; D055515:Cysteine-Rich Protein 61; C499515:FOXO3 protein, rat; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; C474033:FoxO3 protein, mouse; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D019821:Simvastatin