Hdac4 Modulates Cranial Neural Crest Mesenchymal Cells In Intramembranous Ossification

Congenital craniofacial developmental defects refer to congenital abnormalities in the bones or soft tissues of the head and face, accounting for one-third of all congenital defects.The specific pathogenic mechanisms involve transcription factors, signaling molecules, and epigenetic regulatory factors. Among these, histone deacetylase 4 (HDAC4) plays a crucial regulatory role. However, further research is needed to clarify the molecular mechanisms regulating the development of bones in different regions. In this study, we investigated the spatiotemporal expression pattern of Hdac4 during craniofacial development using immunohistochemical staining, immunofluorescence staining, and whole-mount in situ hybridization. Additionally, we established in vitro cell models combined with RNA-seq and Cut&Tag techniques to further explore the molecular mechanisms underlying Hdac4 regulation. We examined the spatiotemporal expression patterns of Hdac4 in the craniofacial skeletons of wild-type and Hdac4fl/fl; Wnt1-Cre mice at different stages of embryonic development, demonstrating that Hdac4 is involved in craniofacial skeletal development. Postnatal Hdac4fl/fl; Wnt1-Cre mice exhibited microcephaly and malocclusion. Immunofluorescence staining combined with in vitro cell line studies revealed that Hdac4 knockdown led to reduced osteoblast proliferation. Additionally, RNA-seq, Cut-tag, and Co-IP analyses suggested potential interactions between Hdac4 and cell cycle regulatory. This study marks the first demonstration of the expression patterns and regulatory roles of Hdac4 in craniofacial development. It significantly enhances our understanding of Hdac4′s involvement in skeletal system development and provides crucial insights for further exploration of the molecular mechanisms by which Hdac4 regulates tooth development.