Fig. 6.

Overview of sensory, nerve-mediated regulation of suture plasticity. The suture is maintained by a balance of expansive progenitor cell proliferation and inward closing mineralization along the bony plates. TrkA⁺ sensory nerves, guided to the cranial suture by NGF, secrete factors such as FSTL1, regulating progenitor activation and expansion and inhibiting BMP-mediated terminal differentiation. TrkA inhibition impairs sensory innervation and reduces suture mesenchyme expansion, resulting in premature suture closure.