GDNF and early-onset autosomal dominant Alzheimer disease: Facilitating neuronal repair: Neural stem cell-derived exosomes containing BDNF, NGF, and miR-132 enhance neuronal survival in ischemic stroke models. Delivering neurotrophic factors: MSC-derived exosomes transport cargo like GDNF, improving dopaminergic neuron survival in Parkinson’s disease. Reducing neuroinflammation: Exosomes carrying miR-124 suppress microglial activation, reducing neuroinflammatory damage in Alzheimer’s disease. Promoting remyelination: Oligodendrocyte-derived exosomes deliver MBP and PLP, supporting remyelination in multiple sclerosis models