Chitooligosaccharides accelarate myelin clearance by Wipi1 mediated Schwann cell autophagy promoting peripheral nerve regeneration

As the most feasible method to reconstruct long-distance peripheral nerve injuries, tissue-engineered nerves rely on biomaterials as a key driving factor. Chitooligosaccharides, intermediate products of chitosan degradation, have the ability to positively regulate nerve regeneration microenvironments. However, the impact of chitooligosaccharides on clearance of myelin debris during Wallerian degeneration is unrevealed. The focus is on exploring the role of chitooligosaccharides in myelin clearance, which is a crucial preparation stage for nerve regeneration. The effects of chitooligosaccharides on nerve regeneration were demonstrated through the morphological and functional evaluations. Then, the myelin lipids and proteins were analyzed using the morphological staining, and molecular and protein detection. The microstructure and ultrastructure observations of lysosomes and autophagosomes were performed. In addition, the proteomics and bioinformatics analysis of injured nerves treated with chitooligosaccharides. The interacting molecules and the regulatory network of Wipi1 were further predicted. On the basis of positive roles on peripheral nerve regeneration, it was illustrated that chitooligosaccharides accelerated the clearance of myelin. Furthermore chitooligosaccharides could regulate lysosomal and autophagic functions, and its role in promoting myelin clearance was mainly related to the enhanced autophagy of Schwann cells rather than macrophages. The big data analysis revealed that Wipi1 was notably upregulated in Schwann cells, mediating chitooligosaccharides to promote autophagy and myelin clearance. Meanwhile, as a potential therapeutic target, Wipi1 significantly accelerated myelin clearance and lipid metabolism after peripheral nerve injury. Our research deepens the comprehensive understanding of the positive regulatory role of chitosan and chitooligosaccharides; and it expands new content and ideas for designing and constructing better tissue-engineered nerves from the perspective of mutual communication and response between biomaterials and body tissues.