Modulating autophagic flux via ROS-responsive targeted micelles to restore neuronal proteostasis in Alzheimer's disease

Compromised autophagy and defective lysosomal clearance significantly contribute to impaired neuronal proteostasis, which represents a hallmark of Alzheimer's disease (AD) and other age-related neurodegenerative disorders. Growing evidence has implicated that modulating autophagic flux, instead of inducing autophagosome formation alone, would be more reliable to rescue neuronal proteostasis. Concurrently, selectively enhancing drug concentrations in the leision areas, instead of the whole brain, will maximize therapeutic efficacy while reduing non-selective autophagy induction. Herein, we design a ROS-responsive targeted micelle system (TT-NM/Rapa) to enhance the delivery efficiency of rapamycin to neurons in AD lesions guided by the fusion peptide TPL, and facilitate its intracellular release via ROS-mediated disassembly of micelles, thereby maximizing autophagic flux modulating efficacy of rapamycin in neurons. Consequently, it promotes the efficient clearance of intracellular neurotoxic proteins, β-amyloid and hyperphosphorylated tau proteins, and ameliorates memory defects and neuronal damage in 3 × Tg-AD transgenic mice. Our studies demonstrate a promising strategy to restore autophagic flux and improve neuronal proteostasis by rationally-engineered nano-systems for delaying the progression of AD.