Fibroblast exosomal TFAP2C induced by chitosan oligosaccharides promotes peripheral axon regeneration via the
Yahong Zhao1, Jina Liu1, Sha Liu1
1Key Laboratory of Neuroregeneration of Jiangsu Province and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19 Qixiu Road, Nantong, Jiangsu, 226001, China.
Abstract:
Chitosan and its degradation product, oligosaccharides, have been shown to facilitate peripheral nerve regeneration. However, the underlying mechanisms are not well understood. In this study, we analyzed the protein expression profiles in sciatic nerves after injury using proteomics. A group of proteins related to exosome packaging and transport is up-regulated by chitosan oligosaccharides (COS), implying that exosomes are involved in COS-induced peripheral nerve regeneration. In fact, exosomes derived from fibroblasts (f-EXOs) treated with COS significantly promoted axon extension and regeneration. Exosomal protein identification and functional studies, revealed that TFAP2C is a key factor in neurite outgrowth induced by COS-f-EXOs. Furthermore, we showed that TFAP2C targets the pri-miRNA-132 gene and represses miR-132-5p expression in dorsal root ganglion neurons. Camkk1 is a downstream substrate of miR-132-5p that positively affects axon extension. In rats, miR-132-5p antagomir stimulates CAMKK1 expression and improves axon regeneration and functional recovery in sciatic nerves after injury. Our data reveal the mechanism for COS in axon regeneration, that is COS induce fibroblasts to produce TFAP2C-enriched EXOs, which are then transferred into axons to promote axon regeneration via miR-132-5p/CAMKK1. Moreover, these results show a new facet of fibroblasts in axon regeneration in peripheral nerves.
Insights
Chitosan oligosaccharides (COS) promote peripheral nerve regeneration by enhancing fibroblast-derived exosomes. These exosomes deliver TFAP2C, which regulates miR-132-5p and CAMKK1, ultimately boosting axon regrowth.
Area of Science:
- Neuroscience
- Biochemistry
- Regenerative Medicine
Background:
- Chitosan and its derivatives are known to aid peripheral nerve regeneration.
- The precise molecular mechanisms driving this regeneration remain unclear.
Purpose of the Study:
- To elucidate the mechanism by which chitosan oligosaccharides (COS) promote peripheral nerve regeneration.
- To identify key molecular players involved in COS-mediated nerve repair.
Main Methods:
- Proteomic analysis of sciatic nerves post-injury.
- Treatment of fibroblasts with COS and analysis of derived exosomes (f-EXOs).
- In vitro and in vivo studies using f-EXOs, TFAP2C, miR-132-5p, and CAMKK1.
- Administration of miR-132-5p antagomir in a rat sciatic nerve injury model.
Main Results:
- COS up-regulated proteins involved in exosome packaging and transport.
- COS-treated f-EXOs significantly promoted axon extension and regeneration.
- TFAP2C in exosomes was identified as a key factor for neurite outgrowth.
- TFAP2C targets pri-miRNA-132, repressing miR-132-5p, which in turn regulates CAMKK1, a positive effector of axon extension.
- miR-132-5p inhibition in rats enhanced CAMKK1 expression and improved sciatic nerve regeneration and functional recovery.
Conclusions:
- COS induces fibroblasts to produce TFAP2C-enriched exosomes that promote axon regeneration via the miR-132-5p/CAMKK1 pathway.
- This study reveals a novel role for fibroblasts in peripheral nerve axon regeneration mediated by exosomes.
- TFAP2C and the miR-132-5p/CAMKK1 axis are critical components of COS-driven nerve repair.
