title: Connexin 43 Affects Osteogenic Differentiation of the Posterior Longitudinal Ligament Cells via Regulation of ERK Activity by Stabilizing Runx2 in Ossification.
abstract: OBJECTIVE
  Connexin 43 is one of the most potent gap junction proteins related to osteoblast differentiation and bone formation. We hypothesized that Connexin 43 is a significant factor in osteogenic differentiation in the posterior longitudinal ligament through the regulation of extracellular signal-regulated kinases (ERK) activity by converging on Runt-related transcription factor 2 (Runx2) activity. In this study, we mapped the activity of Connexin 43 to ERK and Runx2 by extracting longitudinal ligament cell for culture and silencing Connexin expression in addition to dexamethasone treatment in vitro.
  
  
  METHODS
  qRT-PCR, Western Blot, and Runx2-responsive Luciferase Reporter Assay were performed to detect the activity of ERK, Runx2 and the expression levels of osseous genes under Connexin 43 modification.
  
  
  RESULTS
  Downregulation of Connexin 43 resulted in suppression of dexamethasone-induced osteogenic differentiation, inhibition of the ERK and Runx2 activity, and reduction of osseous gene expression.
  
  
  CONCLUSIONS
  these data support that Connexin 43 significantly regulates osteogenic differentiation in the cells from posterior longitudinal ligament by altering the activity of ERK, and subsequently causing the modification of Runx2.
authors.affiliation: Department of Orthopedics, Changzheng Hospital, Shanghai, China.
authors.forename: Haisong
authors.initials: H
authors.lastname: Yang
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.forename: Guodong
authors.initials: G
authors.lastname: Shi
authors.forename: Yongfei
authors.initials: Y
authors.lastname: Guo
authors.forename: Dechun
authors.initials: D
authors.lastname: Chen
authors.forename: Deyu
authors.initials: D
authors.lastname: Chen
authors.forename: Jiangang
authors.initials: J
authors.lastname: Shi
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D002070:Butadienes / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D018031:Connexin 43 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D017846:Longitudinal Ligaments / Q000166:cytology* / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D017887:Ossification of Posterior Longitudinal Ligament / Q000378:metabolism / Q000473:pathology; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D002070:Butadienes; D024042:Collagen Type I; D018031:Connexin 43; D050659:Core Binding Factor Alpha 1 Subunit; D009570:Nitriles; D034741:RNA, Small Interfering; C493709:RUNX2 protein, human; C113580:U 0126; D015675:Osteocalcin; D003907:Dexamethasone; D048049:Extracellular Signal-Regulated MAP Kinases; D000469:Alkaline Phosphatase