Nerve-Derived Extracellular Matrix Promotes Neural Differentiation of Bone Marrow Stromal Cells and Enhances Interleukin-4 Efficacy for Advanced Nerve Regeneration.

Facilitating neuronal differentiation of stem cells and microenvironment remodeling are the key challenges in cell-based transplantation strategies for central nervous system regeneration. Herein, the study harnesses the intrinsic pro-neural differentiation potential of nerve-derived extracellular matrix (NDEM) and its specific affinity for cytokines to develop an NDEM-gelatin methacryloyl(gelMA)-based bifunctional hydrogel delivery system for stem cells and cytokines. This system promotes the neural differentiation of bone marrow stromal cells (BMSCs) and optimizes the therapeutic index of Interleukin-4 (IL-4) for spinal cord injury (SCI) treatment. It is observed that incorporating NDEM into the hydrogel system intrinsically promotes BMSC differentiation into neuron-like cells and effectively regulates IL-4 release kinetics to match the neural reconstructing timeframe. Further analysis reveals that trace amounts of endogenous basic fibroblast growth factor (bFGF) detected in NDEM exhibit a potent effect in promoting neural differentiation. The sustained release of IL-4 from the NDEM significantly encourages macrophage polarization toward the M2 phase, optimizing the transplant microenvironment throughout the reconstruction process. This study demonstrates an NDEM-based optimization strategy for hybrid hydrogel to achieve synchronized delivery of stem cells and cytokines in regenerative medicine applications.