Boosting Sensory Nerve-to-Bone Interactions Enhances Hedgehog Mediated Calvarial Bone Repair

Area of Science:

• Skeletal biology
• Neuroscience
• Regenerative medicine

Background:

• Sensory neurons regulate bone repair through neuroregulatory signals.
• Previous studies focused on loss-of-function, limiting understanding of therapeutic potential.
• Boosting nerve-to-bone interactions is underexplored for bone healing.

Purpose of the Study:

• To investigate the therapeutic potential of pharmacologically activating TrkA to enhance bone healing.
• To elucidate the cellular and molecular mechanisms underlying TrkA-mediated bone regeneration.

Main Methods:

• Utilized a mouse calvarial bone defect model.
• Administered a small molecule partial agonist for TrkA.
• Performed single-cell RNA sequencing and pathway analysis.
• Generated conditional knockout mice for Smoothened (Smo) in PDGFRα+ cells.

Main Results:

• TrkA activation induced bone-associated nerve ingrowth and improved calvarial bone healing.
• Single-cell RNA sequencing revealed immune cell enrichment and enhanced osteoblast differentiation.
• Hedgehog signaling pathway activation was implicated in TrkA-mediated regeneration.
• Pro-regenerative effects were abolished in Smo conditional knockout mice.

Conclusions:

• Pharmacologic activation of sensory nerve signaling enhances membranous bone repair.
• Hedgehog pathway activation in osteoprogenitor cells is a key mechanism.
• Targeting nerve-to-bone interactions presents a promising therapeutic avenue for bone regeneration.