Role of TGF-β3 in Regulating Neural Crest Cell Fate and Craniofacial Development: Insights From Zebrafish Models

Background: Craniofacial malformations, caused by dysregulated neural crest cell (NCC) differentiation, affect approximately one-third of newborns worldwide. Although TGFB3 mutations were recently associated with human coronoid process hypertrophy (CPH) and other craniofacial disorders, the mechanisms by which TGF-β3 regulates NCC fate determination through cell-cell communication remains unknown. Methods: A zebrafish model was used to investigate the impact of tgfb3 on craniofacial cartilage and bone development. Additionally, Tgfb3 was knocked down in neural crest stem cells (NCSCs) in vitro to observe cellular changes and effects on chondrogenic and osteogenic differentiation. Results: Knockdown of tgfb3 in zebrafish resulted in impaired cartilage development and bone formation, which was associated with the TGF-β signaling pathway. A reduction in the expression of markers for neural crest cell formation, migration, and differentiation was observed. Although Tgfb3 knockdown did not affect the proliferation capacity of NCSCs, it led to increased apoptosis, reduced migration, and decreased chondrogenic and osteogenic differentiation. The expression of osteogenesis-related proteins and TGF-β/Smad pathway-related proteins was also reduced in NCSCs to varying degrees. Conclusion: Silencing the Tgfb3 gene in zebrafish led to significant impairment in craniofacial cartilage and bone development, clearly highlighting the critical role of TGF-β3 in regulating NCSC fate. These findings underscore the importance of TGF-β3 in maintaining NCSC migration and differentiation.