Changes in signalling pathways in the palatal cleft in CL/Fr mice

Cleft palate is one of the most common congenital diseases. Therefore, elucidating the molecular mechanisms of palate development is crucial for basic science and the clinical field. Cleft palate in mouse with targeted gene mutation is an excellent experimental model for clarifying the mechanisms driving palate development. Cleft palate occurs in two forms: a cleft between the primary and secondary palates (primary cleft palate) and a cleft between the secondary palates (secondary cleft palate). It remains unclear whether primary palate development is under similar molecular control as secondary palate formation, since most of studies have focused on secondary palate development using mutant mice. CL/Fraser (CL/Fr) is a mouse strain that often exhibits spontaneous primary cleft palate; however, the molecular changes in primary cleft palate in CL/Fr mice are not fully understood. Several signaling pathways, including Shh, Fgf, Bmp, and Wnt signaling, have been shown to play key roles in secondary palate development. In the present study, we found that Shh and Wnt signaling pathways were downregulated in the primary cleft palate region in CL/Fr mice.