Periderm Fate during Palatogenesis: TGF-β and Periderm Dedifferentiation

Area of Science:

• Developmental Biology
• Genetics
• Cell Biology

Background:

• Cleft palate, a common congenital disability, arises from failed palatogenesis.
• Successful secondary palate fusion requires proper medial edge epithelial adherence, dependent on periderm elimination.
• Lack of periderm-specific genetic tools has limited understanding of periderm's role in palatal fusion.

Purpose of the Study:

• To develop periderm-specific Cre driver mouse lines for in vivo analysis of periderm fate during palatogenesis.
• To investigate the cellular mechanisms and signaling pathways governing periderm behavior during palate fusion.
• To elucidate the role of transforming growth factor-beta (TGF-β) signaling in periderm function.

Main Methods:

• Generation of constitutive and inducible periderm-specific Cre driver mouse lines using the cytokeratin-6A (Krt-6a) locus.
• In vivo analysis of periderm cell fate and phenotype during palatogenesis using these novel mouse models.
• Genetic manipulation of transforming growth factor-beta type I receptor (Tgfbr1) in periderm to assess its role in palatal fusion.

Main Results:

• Developed Krt6a-driven Cre driver lines enabling spatial and temporal control of periderm manipulation.
• Observed periderm cells dedifferentiating into cuboidal cells prior to palatal shelf contact.
• Demonstrated that 33% of embryos lacking Tgfbr1 in the periderm exhibit complete cleft secondary palate, with failed periderm dedifferentiation.

Conclusions:

• Periderm cell fate during palatogenesis involves dedifferentiation into a basal epithelial-like state.
• TGF-β signaling is critical for periderm dedifferentiation, a necessary step for palatal epithelial adhesion and fusion.
• Novel periderm-specific mouse models facilitate detailed study of palatogenesis and associated congenital disabilities.