Fig. 3

MSC-Exo cross the blood-brain barrier (BBB) through endocytosis and internalization by brain microvascular endothelial cells (ECs) or via the paracellular pathway. The complex components within MSC-Exo mediate and regulate neuroprotective factors such as pro-inflammatory factors, anti-inflammatory factors, Aβ-degrading enzymes, as well as damaging factors, which target different nerve cells to exert their functions. Consequently, they can reduce Aβ deposition and oxidative stress, regulate neuroinflammatory responses, promote mitochondrial autophagy, and ultimately achieve the effect of treating neurodegenerative diseases