Next-Generation Sequencing Facilitates Quantitative Analysis of the Effects of Wnt Agonist Treatments on Palate Formation

Nonsyndromic clefts of the palate and/or lip are common birth defects arising in about 1/700 live births worldwide. They are caused by multiple genetic and environmental factors, can only be corrected surgically and require complex post-operative care that imposes significant burdens on individuals and society. Our understanding of the molecular networks that control palatogenesis has advanced through studies on mouse genetic models of cleft palate. In particular, the transcription factor Pax9 regulates palatogenesis through the Bmp, Fgf and Shh pathways in mice. But there is still much to learn about Pax9''s relationship with other signaling pathways in this process. Here we show alterations of Wnt expression and decreased Wnt activity in Pax9-/- palatal shelves are a likely result of Pax9''s ability to directly bind and repress the promoters of Dkk1 and Dkk2, proteins that antagonize Wnt signaling. We exploited this relationship by delivering small-molecule Dkk inhibitors into the tail-veins of pregnant Pax9+/- females from E10.5 to E14.5. Such therapies restored Wnt signaling, promoted cell proliferation, bone formation and fusion of palatal shelves in Pax9-/- embryos. These data uncover a connection between the roles of Pax9 and Wnt genes in palatogenesis and offer a new approach for treating human cleft palates. Overall design: E14 embryos of Pax9-/- and control littermates with or without WAY-262611 treatment, mouse embryos palate were micro-dissected, control and mutant samples were separated and individually lysed for the RNA extraction.

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Jia S, Zhou J, Fanelli C, Wee Y, Bonds J, Schneider P, Mues G, D'Souza RN