title: Lithium inhibits palatal fusion and osteogenic differentiation in palatal shelves in vitro.
abstract: OBJECTIVE
  Glycogen synthase kinase-3β (Gsk-3β)/β-catenin signaling regulates development of the secondary palate. It has been unclear about the effects of Gsk-3β/β-catenin signaling on palatal fusion and osteogenic differentiation in palatal shelves.
  
  
  METHODS
  In this study, palatal shelves from mouse embryonic day 13 (E13) were cultured in vitro with or without lithium chloride (LiCl). Palatal fusion was evaluated by haematoxylin-eosin staining. The expression of osteogenic markers in palatal shelves was measured by quantitative PCR, and immunohistochemical staining. Cell proliferation and apoptosis were examined by Ki-67 immunohistochemical and TUNEL staining, respectively. Gsk-3β expression was evaluated by quantitative PCR and Western blotting. β-catenin protein expression was evaluated by Western blotting.
  
  
  RESULTS
  After the treatment with 10 mM LiCl, palatal shelves failed to fuse, and the mRNA and protein levels of osteogenic markers were reduced compared with controls. The number of Ki67-positive cell in the palatal osteoid was significantly higher in the LiCl group than in the controls. The apoptotic cells in the midline epithelial seam were reduced by LiCl. Gsk-3β mRNA and protein expression levels decreased and β-catenin protein expression levels increased by treatment of LiCl.
  
  
  CONCLUSIONS
  Our findings show that LiCl-mediated GSK3β inhibition prevents palatal fusion and osteogenic differentiation in palatal shelves by increased β-catenin signaling. It indicated that overactivation of canonical Wnt signaling might impair the fusion of the secondary palate.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University Luoyu Road 237, 430079 Wuhan, Hubei, PR China; Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Liuyan
authors.initials: L
authors.lastname: Meng
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University Luoyu Road 237, 430079 Wuhan, Hubei, PR China.
authors.forename: Xinhuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Tumor Immunology, Nijmegen Center for Molecular Life Science, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Ruurd
authors.initials: R
authors.lastname: Torensma
authors.affiliation: Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: h.vondenhoff@radboudumc.nl.
authors.forename: Johannes W
authors.initials: JW
authors.lastname: Von den Hoff
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University Luoyu Road 237, 430079 Wuhan, Hubei, PR China. Electronic address: kqyywjtx@hotmail.com.
authors.forename: Zhuan
authors.initials: Z
authors.lastname: Bian
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002972:Cleft Palate / Q000139:chemically induced*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D018021:Lithium Chloride / Q000633:toxicity*; D051379:Mice; D010012:Osteogenesis / Q000187:drug effects*; D010159:Palate / Q000187:drug effects* / Q000196:embryology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D051153:Wnt Proteins / Q000187:drug effects; D051176:beta Catenin / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D051153:Wnt Proteins; D051176:beta Catenin; D018021:Lithium Chloride
keywords: Gsk3β; LiCl; Osteogenic differentiation; Palatal fusion