title: Roles of notch signalling in mandibular condylar cartilage.
abstract: OBJECTIVE
  Notch proteins are cell surface transmembrane spanning receptors which mediate critically important cellular functions through direct cell-cell contact. Interactions between Notch receptors and their ligands regulate cell fate decisions such differentiation, proliferation and apoptosis in numerous tissues. We have previously shown using immunohistochemistry that Notch1 is localized primarily to the prechondroblastic (chondroprogenitor) layer of the mandibular condylar cartilage (MCC).
  
  
  OBJECTIVE
  To test if Notch signalling changes patterns of proliferation and differentiation in the MCC and to investigate if Notch signalling acts downstream of Fibroblast Growth Factor 2 (FGF-2).
  
  
  METHODS
  Condylar cartilage explants were cultured over serum-free DMEM containing either 0 or 50nM DAPT, a Notch signal inhibitor. Explants were used for RNA extraction and immunohistochemistry.
  
  
  RESULTS
  Analysis of gene array data demonstrated that the perichondrial layer of the MCC is rich in Notch receptors (Notch 3 and 4) and Notch ligands (Jagged and Delta) as well as various downstream facilitators of Notch signalling. Disruption of Notch signalling in MCC explants decreased proliferation (Cyclin B1 expression) and increased chondrocyte differentiation (Sox9 expression). Moreover, we found that the actions of FGF-2 in MCC are mediated in part by Notch signalling.
  
  
  CONCLUSIONS
  These data suggest that Notch signalling contributes to the regulation of proliferation and differentiation in the MCC.
authors.affiliation: Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, USA. Electronic address: mserrano@bcd.tamhsc.edu.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Serrano
authors.affiliation: Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: So
authors.affiliation: Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hinton
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002356:Cartilage / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D007150:Immunohistochemistry; D008335:Mandibular Condyle / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D060888:Real-Time Polymerase Chain Reaction; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D008565:Membrane Proteins; D051881:Receptor, Notch1; D016222:Fibroblast Growth Factor 2
keywords: Condylar cartilage; Fibroblast growth factor; Gene array; Notch; Temporomandibular joint