Palatogenesis is tightly regulated at cellular and molecular levels. Cranial neural crest cells (CNCCs), multipotent stem cells that generate most palatal mesenchyme, self-renew, decide fate, and differentiate under cues from their stem cell niche. Orofacial clefts (OFC), among the most common congenital birth defects, arise when CNCC-mediated palate formation is disturbed. Here we review genes, epigenetic machineries, and environmental insults regulating secondary palate development, focusing on CNCC stem cell biology and translational perspectives in tissue engineering, gene therapy, and regenerative medicine for OFC. Canonical signaling pathways regulating palatal shelf proliferation, growth, elevation, and fusion, including Tgf-beta superfamily and Bmp, Fgf, Wnt, and Shh, function as morphogens directing tissue morphogenesis and as regulators of the progenitor niche derived from neural crest cells, balancing proliferation and differentiation. We also overview debated topics such as signaling crosstalk and dissolution of MES. DNA methylation, histone marks, and noncoding RNAs comprise the epigenetic machinery preserving CNCC identity and plasticity. Environmental exposures including smoking, alcohol consumption, and folate deficiency disrupt genetic and epigenetic programs, perturb normal palate development, and elevate OFC risk. Finally, we discuss emerging technologies including single-cell multi-omics, organoids, and CRISPR-based epigenome editing. We propose an integrative conceptual model that places CNCC state transitions at the center of a complex regulatory network. This model emphasizes that disruption at any level, whether arising from niche interactions, epigenetic programming, or environmental exposures, can precipitate cleft palate pathogenesis.
Won et al. (Mon,) studied this question.