Netrin-1 engineered endothelial cell exosomes induce the formation of pre-regenerative niche to accelerate peripheral nerve repair [miRNA-seq]

The formation of vascular niche is pivotal during the early stage of peripheral nerve regeneration. This antecedent angiogenesis meets the nutrient requirements for subsequent rapid axon regeneration and remyelination. Nevertheless, the mechanisms of vascular niche in the regulation of peripheral nerve remain unclear. The axon guidance molecule Netrin-1 (NTN1) is widely expressed in peripheral nerves and particularly was found up-regulated in sciatic nerve stump after peripheral nerve injury (PNI). Herein, we demonstrated that NTN1-high endothelial cells (NTN1+ECs) were the critical component of vascular niche, fostering angiogenesis, axon regeneration and repair-related phenotypes. And we also found that NTN1+ECs derived exosomes (NTN1 EC-EXO) were involved in the formation of vascular niche as a critical role. Multi-omics analysis further verified that NTN1 EC-EXO carried a low-level expression of let7a-5p and activated key pathways associated with niche formation including focal adhesion, axon guidance, PI3K-AKT signaling pathway and mTOR signaling pathway. Taken together, our findings suggested the potential construction of a pre-regenerative niche induced by NTN1 EC-EXO, thereby establishing a conductive microenvironment for nerve repair and facilitating the functional recovery after PNI in the early injury phase. Overall design: 6 samples from PC12 cells