Dynamic molecular landscape in dorsal root ganglion for peripheral nerve regeneration promoted by tissue engineered nerve graft.

Introduction: The limited regenerative capacity of the nervous system represents a significant clinical challenge in the context of peripheral nerve injuries. An innovative strategy for sciatic nerve repair has been developed using tissue-engineered nerve grafts (TENGs) composed of skin-derived precursor Schwann-like cells (SKP-SCs) and a silk fibroin-chitosan scaffold. However, the reason why SKP-SCs-TENG demonstrated superior enhanced nerve regeneration compared to the autograft and scaffold groups remains unclear.

Objectives: The present work aims to elucidate the superiority and molecular mechanisms underlying TENG repairs.

Methods: We conducted a comprehensive transcriptomic analysis of the rat dorsal root ganglia (DRG, L4-L6). A range of key processes were examined, including apoptosis, proliferation, migration, inflammation, the immune response, axonal outgrowth and myelination. To further elucidate the mechanism, LC-MS/MS analysis of SKP-SCs conditioned medium and RNA sequencing of cocultured DRG neurons were carried out.

Results: Post-implantation analyses demonstrated enhanced nerve regeneration, as evidenced by molecular data from gene set enrichment analysis and real-time PCR. A bioinformatics analysis including causal network analysis, upstream regulators prediction, and protein-protein interaction network analysis identified several candidate secreted proteins, including neurotrophic and pro-regenerative factors, which were mapped to key signaling pathways implicated in nerve repair. The results of the co-culture experiments with DRG neurons provided direct evidence of the paracrine effects of SKP-SCs, which enhanced neuronal survival and outgrowth. Bioinformatics analysis on RNA sequencing of DRG neurons further highlighted the molecular pathways that were modulated by the secreted factors of SKP-SCs.

Conclusion: This integrated approach demonstrates the potential of combining biomaterial scaffolds, cellular therapy, and omics technologies for developing effective strategies to repair peripheral nerve injuries. The findings provide a robust preclinical foundation for advancing TENG-based therapies toward clinical application.