Yeast-Produced Sleep Peptide Crosses Brain Barrier, Effectively Treats Insomnia in Mice

Insomnia is a pervasive global health issue affecting millions, characterized by difficulty falling or staying asleep, leading to significant daytime impairment and increased risk of chronic diseases. Current pharmacological treatments often come with undesirable side effects, tolerance development, and dependency concerns. Delta sleep-inducing peptide (DSIP) is a naturally occurring neuropeptide with sleep-promoting properties, but its therapeutic application is severely limited by its poor ability to cross the blood-brain barrier (BBB), the protective physiological barrier that restricts substances from entering the brain. This study addresses the critical challenge of delivering therapeutic peptides like DSIP to the brain by engineering a novel fusion peptide produced by yeast, aiming to enhance BBB penetration and improve sleep outcomes in an insomnia model.

The engineered DSIP fusion peptide demonstrated remarkable success in traversing the blood-brain barrier, achieving brain concentrations that were 2.8-fold higher than those observed with native DSIP (p<0.001). This enhanced delivery translated into significant improvements in sleep metrics in the insomnia models. > Mice treated with the 1.0 mg/kg dose of the DSIP fusion peptide exhibited a substantial 48% increase in total sleep time and a 38% reduction in sleep latency (the time taken to fall asleep) compared to saline-treated controls (p<0.001). The lower dose of 0.5 mg/kg also significantly improved sleep, increasing total sleep time by 32% and reducing sleep latency by 25% (p<0.01). Furthermore, the fusion peptide restored normal sleep architecture, increasing REM sleep by 20% and non-REM sleep by 25% compared to untreated controls (p<0.05), indicating a more natural sleep pattern.