Restoration of autophagy-lysosomal function via transcranial focused ultrasound stimulation ameliorates β-amyloid pathology and cognitive deficits in an Alzheimer's disease model.

Transcranial focused ultrasound (FUS) is a non-invasive neuromodulation technique that regulates intracellular functions and treats brain disorders. In Alzheimer's disease (AD), impaired autophagy-lysosomal pathway (ALP) function leads to the accumulation of β-amyloid (Aβ). However, the potential of FUS alone to alleviate AD pathology by restoring ALP function remains unexplored. In this study, sixteen male transgenic mice with five familial Alzheimer's disease mutations (5×FAD) received bilateral FUS targeting the hippocampus and were compared with sixteen age-matched untreated male 5×FAD mice. Cognitive function was evaluated using behavioral tests, and Aβ pathology was analyzed by immunofluorescence. RNA sequencing, western blotting, and electron microscopy were employed to assess the effects of FUS on the ALP. The results indicated that FUS reduced Aβ deposition and ameliorated cognitive deficits. Compared with the AD group, FUS treatment significantly reduced escape latency by 40.9% (p = 0.010), increased the novel object recognition index by 38.2% (p = 0.016), and increased spontaneous alternation by 18.2% (p = 0.009). Critically, FUS enhanced lysosomal biogenesis and improved autophagosome-lysosome fusion, increasing colocalization efficiency from 28.07 ± 3.73% to 53.22 ± 4.85% in the cortex (p = 0.009) and from 31.95 ± 3.65% to 48.00 ± 2.18% in the hippocampus (p = 0.026). It also promoted the nuclear translocation of transcription factor EB (TFEB). Moreover, the ALP antagonist chloroquine (CQ) suppressed the beneficial effects of FUS, indicating that FUS exerts therapeutic effects in an ALP-dependent manner. Our findings demonstrate that restoring ALP via FUS is a crucial mechanism for mitigating Aβ pathology.