Lactoferrin-modified MSC-derived extracellular vesicles facilitate BBB penetration and enhance gastrodin-induced neuroprotection in Parkinson's disease: involvement of mitophagy.

BACKGROUND

The blood-brain barrier (BBB) severely impedes neuroprotective agent delivery to the brain in Parkinson's disease (PD). Although gastrodin (Gas) possesses neuroprotective properties, its efficacy is limited by poor BBB permeability. This study aimed to develop a brain-targeted extracellular vesicle (EV) delivery system for Gas and elucidate its neuroprotective mechanisms.

METHODS

A brain-targeted EV delivery system was developed using mesenchymal stem cell-derived EVs modified with lactoferrin (Lf). Gas was loaded into Lf-EVs via sonication to construct Lf-EVs-Gas nanocomplexes. The nanocomplexes were characterized by transmission electron microscopy, western blotting, and nano-flow cytometry. Trans-Barrier transport was evaluated using an in vitro Transwell BBB model (hCMEC/D3 cells), while therapeutic efficacy and biodistribution were assessed in an MPTP-induced PD mouse model.

RESULTS

Lf-EVs-Gas exhibited a typical cup-shaped morphology, with a mean size of 79.08 nm and a drug loading efficiency of 47.08 ± 4.63%. Lf functionalization significantly enhanced BBB transport, achieving a brain Gas concentration of 10.34 ± 2.7 ng/g in PD mice versus undetectable levels for free Gas. The targeted system demonstrated superior brain accumulation versus non-targeted vesicles. In 6-OHDA-treated SH-SY5Y cells and MPTP-induced PD mice, the system upregulated tyrosine hydroxylase, reduced α-synuclein aggregation, inhibited neuronal apoptosis, and improved motor function. Mechanistically, these protective effects of Lf-EVs-Gas were associated with activation of PINK1-related mitophagy, as evidenced by elevated LC3-II/LC3-I ratio and increased TOMM20/LC3 colocalization.

CONCLUSION

Lf-EVs-Gas enhanced the brain delivery of Gas and produced neuroprotective effects in cellular and mouse toxin-based models of PD. These effects were associated with the activation of PINK1-related mitophagy, supporting Lf-modified EVs as a promising brain-targeted delivery platform for Gas. Further studies establishing mechanistic causality, long-term safety, and efficacy in progressive PD models are warranted.