Abstract

Ectomesenchymal stem cells (EMSCs) are critical for craniofacial bone development, and low-affinity nerve growth factor receptor (LNGFR) is closely associated with their stemness. However, the specific role of LNGFR in EMSC osteogenesis remains unclear. Here, we investigated this using Lngfr knockout ( lngfr -/- ) mice and demonstrated that lngfr -/- EMSCs exhibited decreased proliferation, migration, and osteogenic differentiation capacities in vitro. Furthermore, impaired skeletal development and reduced mineralization were observed in lngfr -/- fetal mice in vivo. Circular RNA (circRNA) sequencing identified the growth hormone (GH) pathway as a key factor involved in LNGFR-regulated osteogenesis of EMSCs. Co-immunoprecipitation (Co-IP) assays further confirmed the interaction between LNGFR and growth hormone receptor (GHR). lngfr -/- suppressed GHR expression and Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) phosphorylation, leading to downregulation of the GH/insulin-like growth factor 1 (IGF-1) signaling pathway. Modulation of the JAK/STAT pathway affected osteogenesis, while exogenous GH rescued the osteogenic defects via the GHR/JAK-STAT/IGF-1 axis. Collectively, these findings demonstrated that LNGFR promoted EMSC osteogenesis by activating the GHR/JAK-STAT/GH-IGF-1 signaling axis, providing new insights into craniofacial development and regenerative medicine.