Intranasal Treatment of Stem Cell-derived Extracellular Vesicles for Alzheimer's Disease - Project Summary This project's principal goal is to develop a non-invasive, extracellular vesicle (EV) based therapeutic strategy for improving brain function in Alzheimer's disease (AD). A novel approach that investigates the efficacy of intranasal (IN) administration of therapeutic EVs generated from human induced pluripotent stem cell (hiPSC)- derived neural stem cells (NSCs) in mouse models of AD are proposed. The scientific premise is that hNSC- derived EVs (hNSC-EVs) carrying a cargo of beneficial miRNAs and neuroprotective proteins can activate advantageous signaling pathways in target cells, positively modulate the brain microenvironment, microglia, and neurogenesis in the brain, and improve brain function after injury or disease. Notably, preliminary studies have shown that IN administration of hNSC-EVs results in their incorporation by neurons and microglia in virtually all brain regions in 5XFAD mice and leads to better cognitive and mood function, higher levels of hippocampal neurogenesis, and reductions in oxidative stress, neuroinflammation, and amyloid deposits. This project, using mouse models of AD, will test the hypothesis that IN administration of hNSC derived EVs: (i) in the early stage of AD will maintain better cognitive and mood function; and (ii) in the advanced stage of AD will reverse cognitive and mood dysfunction with significant modulation of neuropathology. Studies in Specific Aim 1 will employ 5XFAD mice and investigate whether intervention with hNSC-EVs in the early stage of AD would maintain better cognitive and mood function and whether such positive effects persist for prolonged periods. Investigations in Specific Aim 2, using both 5XFAD and A-beta-Knock-in mice, will test whether IN administration of hNSC-EVs in the advanced stage of AD would reverse cognitive and mood dysfunction. Specific Aim 3 studies will ascertain the role of microglial modulation in hNSC-EV mediated improvements in cognitive and mood function in 5XFAD mice through selective microglia depletion using PLX5622 introduced through diet. Studies in Specific Aim 4 will first examine changes in the antiinflammatory property of hNSC-EVs with knock-down or overexpression of specific miRNAs and proteins, using hiPSC-derived microglia cultures. Next, the effects of IN administration of hNSC-EVs overexpressing the select miRNA and/or protein having robust antiinflammatory activity will be tested in 6 months old 5XFAD mice to determine whether such a strategy would improve the therapeutic benefits of hNSC-EVs in the advanced stage of AD. Both male and female mice will be employed. The hippocampus and the medial prefrontal cortex will be rigorously examined for the various cellular and molecular changes mediated by hNSC-EVs in all Aims. Particularly whether functional improvements with hNSC-EV treatment would comprise the suppression of oxidative stress and neuroinflammation, a higher level of hippocampal neurogenesis, and reductions in amyloid-beta deposits, p-tau, synapse loss, and neurodegeneration will be ascertained. The proposed translational research studies are highly conducive to developing an allogeneic hNSC-EV therapy for AD.
