Stem Cell-Derived Extracellular Vesicles Ameliorate the Neuron Mitochondrial Damage Induced by ROS-, LPS-Exposure: In Vitro Model of Neuron, Microglia, and Astrocyte Triple Co-Culture

Oxidative stress causes brain damage contributing to neurodegenerative and vascular diseases. In Alzheimer’s disease (AD), elevated oxidative stress and mitochondrial damage are closely linked to misfolded protein accumulation. ROS also plays a major role in ischemic brain injury, particularly during reperfusion, impairing the blood–brain barrier and highlighting the association between vascular pathology and AD. To investigate perturbations in brain cells occurring in mixed dementia (AD combined with vascular dementia components), we used a triple culture system comprising neurons, astrocytes, and microglia and induced neuronal injury by combining LPS and H2O2 exposures. Cell viability assays revealed that neuronal death occurred mainly through apoptosis and DNA damage. In neurons and astrocytes exposed to LPS+H2O2, the expression of NADPH oxidase isoform 2, a major source of ROS, increased, along with FOXO3 and SOD2, a key mitochondrial ROS scavenger. Indeed, these changes were accompanied by altered mitochondrial morphology and integrity, as well as reduced neurite extension and thickness. The treatment with extracellular vesicles (EVs) derived from amniotic fluid stem cells was tested due to their rich content of antioxidant molecules. Interestingly, EVs reversed the negative effects of LPS+H2O2, suggesting the protective role against neuronal injury in vitro may be mediated by the EV-cargo.