Hedgehog signaling enhances the Schwann-like and nerve repair-supportive properties of ectomesenchymal stem cells.

INTRODUCTION

Peripheral nerve injury (PNI) is characterized by limited regenerative capacity and incomplete functional recovery. Schwann cells (SCs) are essential for nerve repair, but their clinical application is constrained by limited availability. Ectomesenchymal stem cells (EMSCs), derived from neural crest lineage, represent a promising alternative; however, their inefficient differentiation into SC-like cells remains a key limitation. This study investigated whether activation of Hedgehog signaling via Sonic hedgehog (Shh) could enhance SC-like differentiation and improve nerve regeneration.

METHODS

EMSCs were isolated from rat nasal mucosa and transduced with adenoviral vectors to overexpress Shh. SC-like differentiation was assessed using RT-qPCR, Western blot, immunofluorescence, and ELISA. Transcriptomic analysis compared EMSCs with primary SCs. A short-gap rat sciatic nerve defect model was established as an initial proof-of-concept in vivo model, and animals received vehicle, EMSCs, Shh-EMSCs, or autograft treatment. Functional recovery, electrophysiology, histology, and ultrastructural analyses were performed.

RESULTS

Transcriptomic analysis revealed that EMSCs possess a partial SC-related transcriptional profile but lack sufficient Hedgehog activation. Shh overexpression activated canonical Hedgehog signaling, evidenced by increased Gli1/2 expression and nuclear translocation. Shh-EMSCs showed enhanced expression of SCs markers (P75, GFAP, MBP, S100β), increased secretion of neurotrophic factors (BDNF, NT-3), and reduced inflammatory cytokines. In vivo, Shh-EMSCs significantly improved functional recovery, nerve conduction velocity, and gait performance compared with EMSCs alone. Histological and ultrastructural analyses demonstrated increased axonal regeneration, improved organization, and enhanced myelination compared with unmodified EMSCs, although autograft repair remained superior or more complete in several outcome measures.

CONCLUSION

Hedgehog signaling contributes to SC-like differentiation of EMSCs. Shh-mediated activation promotes a pro-regenerative phenotype and enhances nerve repair-related outcomes in a short-gap sciatic nerve defect model, suggesting that Shh-EMSCs may serve as a potential cell-based strategy for peripheral nerve repair.