The canonical bone morphogenetic protein (BMP) signaling pathway plays a crucial regulatory role in tooth development by activating Smad proteins to regulate gene expression. We previously identified an atypical canonical BMP signaling in dental mesenchyme that is Smad4-independent but Smad1/5-dependent. This study demonstrates that phosphorylated Smad1/5 (pSmad1/5) and Smad4 regulate distinct gene sets in murine dental mesenchyme. Real-time monitoring of BMP-Smad transcriptional activity revealed that Smad4-dependent canonical BMP signaling is restricted to neurovascular cells surrounding the condensed dental mesenchymal cells where pSmad1/5 is present. Notably, pSmad1/5 in dental mesenchymal cells form complexes with pSmad3 to prevent canonical BMP signaling. CUT&RUN assays revealed genome-wide co-occupancy of pSmad1/5 and pSmad3, indicating their function as transcriptional regulation units. Integrative analyses demonstrated that this atypical canonical BMP signaling regulates tooth sensory innervation and maintains odontogenic inductive potential in dental mesenchyme, enabling the identification of crucial genes for maintaining tooth inductive capability. Our findings elucidate the operating mechanism of atypical canonical BMP signaling in dental mesenchymal cells and clarify how BMP-Smad signaling exerts diverse functions across different cell types, informing future tooth bioengineering strategies.

Keywords:
Atypical canonical BMP-Smad signaling, Dental mesenchyme, Tooth sensory innervation, Odontogenic inductive potential, Mouse
Subjects:
Gene regulation, Regeneration, Signalling

Author contributions

Conceptualization: Q.T., L.L., Y.C.; Data curation: Q.T., L.L., Y.L., Y.C.; Formal analysis: Q.T., L.L., Y.L., Y.C.; Funding acquisition: Y.C.; Investigation: Q.T., L.L., A.W., H.L., L.W., C.G., Y.C.; Methodology: Q.T., L.L., A.W., H.L., L.W., C.G., Y.C.; Project administration: Q.T., L.L., A.W., H.L., L.W., C.G., Y.C.; Resources: H.-J.E.K., Y.C.; Supervision: H.-J.E.K., Y.C.; Validation: Q.T., L.L., Y.L., A.W., H.L., L.W., C.G., Y.C.; Visualization: Q.T.; Writing – original draft: Q.T., L.L., Y.L., A.W., J.-M.L., Z.W., H.-J.E.K., Y.C.; Writing – review & editing: Q.T., L.L., Y.L., A.W., J.-M.L., Z.W., H.-J.E.K., Y.C.

Funding

This research was supported by the National Institutes of Health (NIH) grants R01DE024152 to Y.C. and R01DE033085 to H.-J.E.K. Deposited in PMC for release after 12 months.

Data and resource availability

All the bulk RNA-seq, ChIP-seq and CUT&RUN datasets were deposited in GEO with SuperSeries accession number GSE297138. Our unpublished scRNA-seq dataset on E13.5 dental mesenchyme shown in Fig. S6 is available upon request to the corresponding author.

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2025
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