Delivery of HSP70 mRNA via exosomes ameliorates sleep deprivation-induced cognitive impairments in mice

Chronic sleep deprivation impairs cognition and triggers neuroinflammation, but effective molecular therapies are lacking. Heat shock protein 70 (HSP70) offers neuroprotection, though its delivery across the blood-brain barrier remains a challenge. This study investigates exosomes as a vehicle to enhance brain delivery of HSP70 for treating chronic sleep deprivation. We engineered HEK293T cells to stably express HSP70 mRNA and the brain-targeting RVG-Lamp2b fusion protein, generating HSP70@Exo^RVG exosomes. These were characterized via transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. In vitro uptake and HSP70 expression were assessed in neural progenitor cells (NPCs). In vivo efficacy was evaluated in a sleep-deprived mouse model using behavioral tests and molecular analyses of inflammatory and neurotrophic markers. HSP70@Exo^RVG exosomes efficiently delivered HSP70 mRNA to NPCs, increasing intracellular HSP70 protein. In vivo, systemic administration restored memory performance, reduced hippocampal TNF-α, IL-6, and IL-1β levels, and increased IL-10. Treatment also elevated brain-derived neurotrophic factor and phosphorylated CREB, indicating enhanced neurotrophic signaling. These effects surpassed those of non-targeted or empty exosomes. Engineered exosomes enabled effective brain-targeted HSP70 mRNA delivery, reversing cognitive and inflammatory consequences of sleep deprivation. To our knowledge, this is the first demonstration of RVG-modified exosomes successfully delivering mRNA (rather than siRNA or miRNA) for the treatment of sleep deprivation-induced deficits. HSP70@Exo^RVG offers a promising, noninvasive therapeutic strategy for sleep-related neurodegenerative conditions and highlights the potential of exosome-based mRNA delivery systems.