BV2 Membrane‐Coated PEGylated‐Liposomes Delivered hFGF21 to Cortical and Hippocampal Microglia for Alzheimer's Disease Therapy

Abstract Microglia‐mediated inflammation is involved in the pathogenesis of Alzheimer's disease (AD), whereas human fibroblast growth factor 21 (hFGF21) has demonstrated the ability to regulate microglia activation in Parkinson's disease, indicating a potential therapeutic role in AD. However, challenges such as aggregation, rapid inactivation, and the blood–brain barrier hinder its effectiveness in treating AD. This study develops targeted delivery of hFGF21 to activated microglia using BV2 cell membrane‐coated PEGylated liposomes (hFGF21@BCM‐LIP), preserving the bioactivity of hFGF21. In vitro, hFGF21@BCM‐LIP specifically targets Aβ 1‐42 ‐induced BV2 cells, with uptake hindered by anti‐VCAM‐1 antibody, indicating the importance of VCAM‐1 and integrin α4/β1 interaction in targeted delivery to BV2 cells. In vivo, following subcutaneous injection near the lymph nodes of the neck, hFGF21@BCM‐LIP diffuses into lymph nodes and distributes along the meningeal lymphatic vasculature and brain parenchyma in amyloid‐beta (Aβ 1‐42 )‐induced mice. Furthermore, the administration of hFGF21@BCM‐LIP to activated microglia improves cognitive deficits caused by Aβ 1‐42 and reduces levels of tau, p‐Tau, and BACE1. It also decreases interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) release while increasing interleukin‐10 (IL‐10) release both in vivo and in vitro. These results indicate that hFGF21@BCM‐LIP can be a promising treatment for AD, by effectively crossing the blood–brain barrier and targeting delivery to brain microglia via the neck‐meningeal lymphatic vasculature‐brain parenchyma pathways.