Zeb2/Axin2-Enriched BMSC-Derived Exosomes Promote Post-Stroke Functional Recovery by Enhancing Neurogenesis and Neural Plasticity

Abstract

Exosomes harvested from bone marrow-derived mesenchymal stromal cells (BMSCs) have shown treatment potential in many diseases. In vitro, Zeb2/Axin2 stimulated endogenous neurogenesis, which induced functional recovery after stroke. Here, we investigated whether the Zeb2/Axin2-enriched exosomes harvested from BMSCs transfected with a Zeb2/Axin2 overexpression plasmid would enhance neurological recovery. Compared with the control, both exosome treatments significantly improved functional recovery, and Zeb2/Axin2-enriched exosomes had significantly more improved effects on neurological function, neurogenesis, and neurite remodeling/neuronal dendrite plasticity than the control BMSC exosome treatment in a middle cerebral artery occlusion MCAO rat model. After stimulation with Zeb2/Axin2-enriched BMSC exosomes, the spatial memory and nerve function of MCAO rats showed marked recovery. The number of neurons was increased in the subventricular zone (SVZ), hippocampus, and cortex area, while the expression of nerve growth factors (NGF, BDNF, etc.) was upregulated. In the ischemic boundary zone, Zeb2/Axin2-enriched exosomes promoted synaptic remodeling by increasing the number of synapses and reversed the axonal loss of phosphorylated neurofilament (SMI-31) and synaptophysin (SYN) caused by ischemic injury, thus alleviating axonal demise and promoting synaptic proliferation. In vitro, Zeb2/Axin2-enriched exosomes significantly increased neurite branching and elongation of cultured cortical embryonic rat neurons under oxygen- and glucose-deprived (OGD) conditions. Moreover, Ex-Zeb2/Axin2-enriched exosomes downregulated the protein level of SOX10, endothelin-3/EDNRB, and Wnt/β-catenin expression. In conclusion, exosomes harvested from Ex-Zeb2/Axin2 BMSC could improve post-stroke neuroplasticity and functional recovery in MCAO rats by promoting proliferation and differentiation of neural stem cells. The mechanism may be related to the SOX10, Wnt/β-catenin, and endothelin-3/EDNRB pathways.

Keywords: Axin2; BMSCs; Exosomes; MCAO; Neurological recovery; Zeb2.