Role of GSK-3β in the osteogenic differentiation of palatal mesenchyme

Emily R. Nelson, Benjamin Levi, Michael Sorkin, Aaron W. James, Karen J. Liu, Natalina Quarto, Michael T. Longaker

Research output: Contribution to journalArticlepeer-review

Abstract

Introduction: The function of Glycogen Synthase Kinases 3β (GSK-3β) has previously been shown to be necessary for normal secondary palate development. Using GSK-3ß null mouse embryos, we examine the potential coordinate roles of Wnt and Hedgehog signaling on palatal ossification. Methods: Palates were harvested from GSK-3β, embryonic days 15.0-18.5 (e15.0-e18.5), and e15.5 Indian Hedgehog (Ihh) null embryos, and their wild-type littermates. The phenotype of GSK-3β null embryos was analyzed with skeletal whole mount and pentachrome stains. Spatiotemporal regulation of osteogenic gene expression, in addition to Wnt and Hedgehog signaling activity, were examined in vivo on GSK-3β and Ihh +/+ and -/- e15.5 embryos using in situ hybridization and immunohistochemistry. To corroborate these results, expression of the same molecular targets were assessed by qRT-PCR of e15.5 palates, or e13.5 palate cultures treated with both Wnt and Hedgehog agonists and anatagonists. Results: GSK-3β null embryos displayed a 48 percent decrease (*p&0.05) in palatine bone formation compared to wild-type littermates. GSK-3β null embryos also exhibited decreased osteogenic gene expression that was associated with increased Wnt and decreased Hedgehog signaling. e13.5 palate culture studies demonstrated that Wnt signaling negatively regulates both osteogenic gene expression and Hedgehog signaling activity, while inhibition of Wnt signaling augments both osteogenic gene expression and Hedgehog signaling activity. In addition, no differences in Wnt signaling activity were noted in Ihh null embryos, suggesting that canonical Wnt may be upstream of Hedgehog in secondary palate development. Lastly, we found that GSK-3β -/- palate cultures were "rescued" with the Wnt inhibitor, Dkk-1. Conclusions: Here, we identify a critical role for GSK-3β in palatogenesis through its direct regulation of canonical Wnt signaling. These findings shed light on critical developmental pathways involved in palatogenesis and may lead to novel molecular targets to prevent cleft palate formation.

Original languageEnglish (US)
Article numbere25847
JournalPloS one
Volume6
Issue number10
DOIs
StatePublished - 2011

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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