Engineered extracellular vesicles-mediated curcumin delivery in brain microenvironment modulating lysosomes, mitochondria, and microglia reprogram for parkinson’s disease therapy

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons, aggregation of α-synuclein (α-Syn), lysosomal dysfunction, and mitochondrial impairment. Curcumin has demonstrated neuroprotective effects against PD pathology; however, its poor bioavailability, rapid systemic clearance, and limited blood-brain barrier permeability remain significant challenges to be overcome. An extracellular vesicle (EV)-based dopamine transporter (DAT)-targeted drug delivery system, derived from genetically engineered HEK293T cells, expressing DAT-targeting single-chain variable fragments (scFv) on the EV surface, is developed. Curcumin is encapsulated into the DAT-targeting EVs (αDAT EVs) for precise delivery into dopaminergic neurons. In the PD cell model, significant EV uptake is observed, with a reduced accumulation of α-Syn, alongside restored expression of DJ-1, TH, and PARKIN following treatment with curcumin-loaded DAT-targeting EVs (Cur@αDAT EVs). In a 6-hydroxydopamine (6-OHDA)-induced PD rat model, Cur@αDAT EVs significantly enhanced motor and cognitive function, protected dopaminergic neurons, and attenuated neuroinflammation, with microglial activation considered a downstream paracrine/bystander effect following neuronal rescue. Accumulation of curcumin in the substantia nigra and ventral tegmental area confirms precise αDAT-EV-mediated delivery, addressing the pharmacokinetic challenges of free curcumin. Overall, DAT-targeting EVs represent a promising precision delivery platform for combating PD.