IntroductionThis study aimed to investigate the impact of miR-137-3p on the pathogenesis of Alzheimer's disease (AD) and develop a pioneering in vivo delivery method for its therapeutic potential. MethodsThis study was initiated by quantifying the levels of miR-137-3p in both human neuroblastoma cells and a mouse model of AD. Our focus was on elucidating its effects on microtubule (MT) stability, tau protein hyperphosphorylation, synaptic damage, and other hallmark features of AD. To circumvent the risks associated with direct brain injections, a novel drug delivery system was engineered, employing lipid nanoparticles (LNPs) functionalized with rabies virus glycoprotein to facilitate the transcytosis of miR-137-3p across the blood-brain barrier and target its delivery directly to neurons. ResultsThe results confirmed miR-137-3p deficiency in both AD cells and animal models. A protective effect of miR-137-3p on MT stability in the AD model was first observed in SH-SY5Y. We validated that the delivery system could effectively penetrate the blood-brain barrier and target neurons, resulting in a significant increase in miR-137-3p levels in the hippocampus of APP/PS1 mice. Glycogen synthase kinase-3 beta expression in the hippocampus of AD mice was inhibited, suggesting successful treatment of AD in this animal model. DiscussionThis study verified a new mechanism of action of miR-137-3p in AD pathogenesis in cells. By developing an LNPs-based miR-137-3p delivery system, this study offers a novel avenue for treating AD, highlighting miR-137-3p as a key factor in AD pathogenesis and its therapeutic application.