title: Leucine-rich amelogenin peptide induces osteogenesis by activation of the Wnt pathway.
abstract: We previously showed that one of the amelogenin splicing isoforms, Leucine-rich amelogenin peptide (LRAP), induced osteogenic differentiation of mouse embryonic stem cells; however, the signaling pathway(s) activated by LRAP remained unknown. Here, we demonstrated that the canonical Wnt/beta-catenin signaling is activated upon LRAP treatment, as evidenced by elevated beta-catenin level and increased Wnt reporter gene activity. Furthermore, a specific Wnt inhibitor sFRP-1 completely blocks the LRAP-mediated Wnt signaling. However, exogenous recombinant Wnt3a alone was less effective at osteogenic induction of mouse ES cells in comparison to LRAP. Using a quantitative real-time PCR array, we discovered that LRAP treatment up-regulated the expression of Wnt agonists and down-regulated the expression of Wnt antagonists. We conclude that LRAP activates the canonical Wnt signaling pathway to induce osteogenic differentiation of mouse ES cells through the concerted regulation of Wnt agonists and antagonists.
authors.affiliation: University of Southern California School of Dentistry, Center for Craniofacial Molecular Biology, 2250 Alcazar Street, Los Angeles, CA 90033, USA.
authors.forename: Rungnapa
authors.initials: R
authors.lastname: Warotayanont
authors.forename: Baruch
authors.initials: B
authors.lastname: Frenkel
authors.forename: Malcolm L
authors.initials: ML
authors.lastname: Snead
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000818:Animals; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D010012:Osteogenesis / Q000235:genetics; D051153:Wnt Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D051176:beta Catenin / Q000378:metabolism; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D003746:Dental Enamel Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051153:Wnt Proteins; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D051176:beta Catenin; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C555510:WNT3A protein, human; C555511:Wnt3a protein, mouse; C067432:leucine-rich amelogenin peptide