c-Kit signaling regulates tooth development by the PI3K-Creb3l2 signaling pathway

c-Kit signaling plays a crucial role in various developmental processes, yet its specific function and mechanistic underpinnings in tooth morphogenesis remain incompletely understood. This study aimed to elucidate the role of c-Kit-mediated signaling in regulating tooth development. We first confirmed the spatiotemporal expression pattern of c-Kit and its associated signaling components in the mouse embryonic tooth germ via RNA single molecule colocalization assay (RNAscope) staining, noting its prominent presence in the dental epithelium (DE). To investigate its functional significance, we generated an epithelial-specific Kit conditional knockout mouse model (Kit-cKO). HE staining revealed that the loss of epithelial c-Kit led to significant developmental delays and profound morphological abnormalities. To unravel the molecular mechanisms downstream of c-Kit ablation, we performed RNA sequencing (RNA-seq) on control and kit-cKO tooth germs. We identified a significant downregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway, a key cascade known to be activated by c-Kit. Further analysis pinpointed a pronounced decrease in the expression of Creb3l2, a transcription factor implicated as a direct effector of PI3K signaling. This downregulation suggested a novel c-Kit/PI3K/Creb3l2 axis in tooth development. Furthermore, the RNA-seq data and subsequent functional assays revealed a concurrent reduction in the expression of key stem cell markers and a significant decrease in epithelial cell proliferation within the Kit-cKO tooth germ. This indicates that the c-Kit-PI3K-Creb3l2 pathway is critically involved in maintaining the progenitor cell pool and driving proliferative expansion necessary for proper organogenesis.