Transplantation of peripheral nerve tissueoid based on a decellularized optic nerve scaffold to restore rat hindlimb sensory and movement functions
Zhaowei Zhu, Ge Li, Guanggeng Wu, Yujing Zhang, Yu‐Rong Bai, Bi‐Qin Lai, Ying Ding, Xiang Zeng, Yuan‐Huan Ma, Shu Liu, Rui Wang, Jing-Hua Liang, Yangbin Xu, Bo He, Yuan‐Shan Zeng
Abstract
Peripheral nerve injury (PNI) involving the loss of sensory and motor functions is challenging to repair. Although the gold standard of PNI repair is still the use of autologous nerve grafts, the destruction of the donor side is inevitable. In the present study, peripheral nerve tissueoids (PNTs) composed of a Schwann cell (SC)-based neurotrophin-3 (NT-3) delivery system and a decellularized optic nerve (DON) with naturally oriented channels were engineered to investigate the mechanism of PNTs in nerve regeneration. Proteomic analysis and mRNA sequencing revealed that PNTs have the advantage of promoting nerve regeneration by the three mechanisms of chemotaxis, adhesion and intrinsic mobilisation. The results demonstrated that a local NT-3-enriched pool was constructed by laminin γ3 (LAMC3) in PNTs, creating a niche for the colonization of TrkC-positive SCs, attraction of axons to the defect/graft area, and remyelination. In addition, LAMC3 in PNTs can rapidly promote axon adhesion through integrin aVβ6 and can precisely guide long projecting axons to target tissues. Furthermore, the interactions among the NT-3/TrkC, LAMC3/integrin aVβ6 and the scaffold synergistically activate the PI3K-AKT signalling pathway in damaged neurons, further stimulating the intrinsic regenerative drive within the neurons to ultimately achieve the rapid reinnervation and the improvement of sensory and movement functions in the hindlimb. A schematic diagram showing that 1.) LN (or LAMC3) on the PNT channel wall can bind to NT-3 to form a pool of local NT-3 enrichment, creating a ecological niche conducive to the colonization and growth of TrkC + SCs and the remyelination of regenerated axons. In addition, the continuous secretion of NT-3 by PNT can regulate the expression of TrkC on sensory neurons and promote the extension of their axons to the defect/graft area. 2.) When axons regenerated into the defect/graft area, LAMC3 in PNT can interact directly with integrin aVβ6 on the axons to guide them through the defect/graft area. 3.) The interaction of NT-3/TrkC with LAMC3/integrin aVβ6 in PNT can synergistically activate the PI3K-AKT signaling pathway in the neurons, resulting in continuous extension and growth of their axons.