Tailored brain metastatic tumor cells-derived apoptotic bodies ameliorate Alzheimer's disease by promoting microglia efferocytosis and neuroinflammation mitigation.

Neuroinflammation, characterized by microglial overactivation and oxidative stress, plays a critical role in the initiation and progression of Alzheimer's disease (AD). In this study, we focus on simulating the natural efferocytosis process to reprogram microglial and mitigate chronic neuroinflammation for combinational AD therapy. To achieve this goal, engineered apoptotic bodies derived from brain metastatic tumor cells (LAbs) are successfully developed. Specifically, LAbs-based nanocomposites were fabricated by hybridizing LAbs with liposomes co-loaded with manganese dioxide nanoenzyme (BMn) and autophagy-activating rapamycin (Rapa), referred to as LAbs@Lip@BMn/Rapa. LAbs@Lip@BMn/Rapa exhibits efficient BBB penetration via LAbs-associated brain metastasis propensity of apoptotic bodies. Within the AD microenvironment, oxygen produced through BMn catalyzation in response to H₂O₂ triggers the structural disintegration of LAbs-camouflaged liposomes and their reassembly into ultra-small vesicles, thereby significantly enhancing intracranial delivery efficiency. In vitro and in vivo experiments confirm that this multi-target strategy effectively normalizes microglia toward anti-inflammatory M2 phenotype, scavenges reactive oxide species (ROS) accumulation, promotes β-amyloid and phosphorylated tau clearance through synergistic intervention, restores the pathological microenvironment in the brain, and enhances cognitive functions in AD model mice. This study demonstrates a novel LAbs-based biomimetic construction strategy that effectively penetrates the BBB and regulates microglia functions, offering a promising approach for AD treatment.