In vitro investigation of miR-206-3p-loaded extracellular vesicles as modulators of Aβ-induced neurodegeneration

In this study, we investigated the therapeutic potential of miR-206-3p delivered via small extracellular vesicles (sEVs) in an in vitro Alzheimer's disease model using SH-SY5Y human neuroblastoma cells treated with amyloid beta (Aβ). The sEV–miR-206-3p complexes were successfully loaded with miR-206-3p (∼0.001 copies per particle) without disrupting vesicle integrity or inducing cytotoxicity at the optimized concentration of 5 μg/mL. Aβ treatment significantly increased oxidative stress markers (ROS, MDA, LDH) and decreased antioxidant enzyme activity (SOD), while GPX1 showed an opposite trend. Furthermore, Aβ elevated proinflammatory gene expression (ICAM1, TNF-α) and reduced neuroprotective BDNF levels, induced mitochondrial dysfunction (increased Cyt-c, PINK1, DNM1L; decreased TFAM), impaired synaptic proteins (CPLX2, ROR1), and promoted tau phosphorylation and Aβ accumulation. Treatment with sEV–miR-206-3p effectively mitigated these alterations, reducing oxidative stress, suppressing neuroinflammatory responses, restoring mitochondrial function and synaptic protein levels, and attenuating tau and Aβ pathology. These findings demonstrate that miR-206-3p-loaded sEVs protect neuroblastoma cells from Aβ-induced neurodegenerative processes, highlighting their potential as a novel drug delivery system for neuroprotection.