EXPRESS: Ultrasound Enhances Glymphatic-Associated Solute Transport via Piezo1-Related Mechanotransduction in 5xFAD Mice

BACKGROUND: Glymphatic dysfunction impairs Aβ clearance and contributes to Alzheimer's disease (AD) progression. Low-intensity transcranial focused ultrasound (LITFUS) can enhance glymphatic cerebrospinal fluid transport, but its therapeutic effects on Aβ clearance and cognitive decline remain unclear. METHODS: 5xFAD mice received bilateral hippocampal LITFUS for 4 weeks. Glymphatic transport was assessed by fluorescent tracer injection and ex vivo imaging. Aβ deposition, Iba1 immunoreactivity, and cognitive function were evaluated by immunohistochemistry and behavioral tests. Piezo1 involvement was examined using GsMTx4, qPCR, and Western blotting of isolated brain vascular fractions. Safety was assessed by blood-brain barrier permeability and H&E staining. RESULTS: LITFUS increased brain-wide CSF tracer influx and hippocampal interstitial solute clearance in 5xFAD mice. It reduced Aβ deposition in the hippocampus and prefrontal cortex, decreased Iba1 immunoreactivity, and improved learning and memory. These effects were associated with increased Piezo1 expression and enhanced CaMKII/eNOS signaling in brain vascular fractions, and were attenuated by GsMTx4. No blood-brain barrier disruption or histological injury was detected. CONCLUSION: LITFUS enhances glymphatic transport, reduces cerebral Aβ burden, and improves cognition in 5xFAD mice, possibly through Piezo1-related mechanotransduction, supporting its potential as a noninvasive AD therapy.