Ultrasonic repression of TRPA1-dependent astrocyte reactivity confers neuroprotection in models of Lewy body dementia
Ji Hun Kim, Keunhyung Lee, Minseok Koo, Doeun Kim, Jin Kyung Hong, Jeong-Yun Choi, Han Seok Ko, Joo-Ho Shin, Joo Min Park, Jinhyoung Park, Yunjong Lee
Translational Neurodegeneration 2026, 15 · 10.1186/s40035-026-00544-6
Abstract
Background The pathology of Lewy body dementia (LBD) features neuronal α-synuclein (α-syn) accumulation and astrocytic hyperactivation in cognitive brain circuits. Ultra-low-intensity ultrasound (ULIUS) modulates astrocyte function via transient receptor potential ankyrin 1 (TRPA1) and has been investigated for therapeutic applications in neurodegenerative diseases. Methods The therapeutic efficacy and mechanisms of ULIUS were evaluated in primary cultured astrocytes and neuron-glia cocultures treated with α-syn preformed fibrils (PFFs), as well as in an LBD model induced by hippocampal α-syn PFF injection into neuronal α-syn-A53T transgenic mice. Astrocytic TRPA1 was modulated under pathologic conditions with ULIUS or a pharmacologic TRPA1 antagonist to determine calcium responses and transcriptional regulation of Trpa1 and inflammation-related genes. Neuropathological analyses for Lewy-like inclusions, neurodegeneration, and inflammation were performed in LBD mouse brains, with or without ULIUS. Spatial learning and memory were assessed using the Barnes maze. Results Repeated transcranial ULIUS application was safe in long-term use and, unlike prolonged stronger ultrasound, did not cause hippocampal inflammation or neurodegeneration. It also prevented neuroinflammation and Lewy-like pathologies, rescuing cognitive impairment in LBD mice. ULIUS abolished α-syn-induced elevation of TRPA1, toll-like receptors-2 (TLR2), interleukin-1β, and tumor necrosis factor-α in LBD mouse brains. Mechanistically, both ULIUS and TRPA1 inhibitor blocked the sustained TRPA1-dependent calcium increase and the expression of inflammation-associated transcripts in α-syn PFF-treated astrocytes. Conclusions Our findings provide mechanistic insights into the reciprocal TRPA1-TLR2 signaling pathway in α-syn-induced astrocyte pathology and underscore the disease-modifying potential of focused transcranial ULIUSm on astrocytes for the treatment of LBD. This study establishes a novel therapeutic strategy to alleviate neuroinflammation and cognitive decline associated with LBD. The demonstration of its long-term safety further supports ULIUS as a promising therapeutic strategy.
Abstract via europepmc.
Exposures
Exposure 1: In vitro ultrasound stimulation of primary cortical neuron-glia co-culture and primary astrocyte culture (Ultrasonocoverslip)
Target: cultured neurons, cultured glia — “primary cortical neuron-glia co-culture and primary astrocyte culture on Ultrasonocoverslip”
Device: custom-built · Ultrasonocoverslip (PVDF-TrFE piezoelectric transducer integrated with glass coverslip)
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 6,000 | ✓✓✓⚑ |
| Pulse duration (ms) | 0.333 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1,500 | ✓✓✓ |
| Duty cycle (%) | 50pulse duration × PRF gives 49.95% | ✓✓✓ |
| Sonication duration (s) | 0.5 | ✓✓✓ |
| Free-field pressure (kPa) | 110 | ✓✓✓ |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | 0.2 | ✓✓✓ |
| In-situ estimate | not applicable | |
| In-situ pressure (kPa) | not applicable | |
| In-situ Isppa (W/cm²) | not applicable | |
| In-situ Ispta (W/cm²) | not applicable |
Cells received three trials of ultrasound stimulation with 2-min intervals in a single day; this session was repeated every 2 days for three sessions total (astrocyte cultures) or every other day for three sessions (neuron-glia co-culture).
Exposure 2: Transcranial ultrasound stimulation of hippocampus (dentate gyrus) in vivo
Target: dentate gyrus — “hippocampus (dentate gyrus, α-syn PFF injection site)”
Device: custom-built · custom-made 1 MHz focused single-element transducer, focal distance 3 mm
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓ |
| Pulse duration (ms) | 0.333 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 1,500 | ✓✓✓ |
| Duty cycle (%) | 50pulse duration × PRF gives 49.95% | ✓✓✓ |
| Sonication duration (s) | 0.5 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | measurementsingle value | |
| In-situ pressure (kPa) | 110 | ✓✓✓ |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Ispta, domain unspecified (W/cm²) | 0.2 | ✓✓✓ |
Ultrasound was delivered to the injected hippocampal region across the intact skull three times per day with 2-min intervals; this session was repeated every 3 days for 1 month, for a total of 10 sessions, under 1% isoflurane anaesthesia. A separate safety comparison in wild-type mice used a stronger paradigm (2.5 W/cm2, 10 sessions over one month) alongside the main 0.2 W/cm2 paradigm.
Flags from extraction
exposures[0].fundamental_frequency_khz— Methods state the stimulation used '333-μs-long 6-MHz bursts', but the Results section separately states 'the operational frequency of the transducer was 6.1 MHz'; recorded as 6 MHz (6000 kHz) per the stimulation-protocol sentence, minor discrepancy with the 6.1 MHz figure-caption value.n_subjects— Multiple cohorts (wild-type safety mice, alpha-syn transgenic LBD mice, littermate controls) and multiple assays with different per-group n (e.g. n=10 for Barnes maze, n=5 for immunohistochemistry, n=3 for western blot) are reported; no single total number of ultrasound-exposed animals is stated.exposures[1].unspecified_domain.isppa_w_cm2— 0.2 W/cm2 is the main therapeutic ISPTA used throughout; 2.5 W/cm2 is a separate higher-intensity paradigm tested only for safety comparison in wild-type mice, not used in the LBD therapeutic experiments; domain (pre- vs post-cranial) not stated for either intensity value.exposures[0].target.terms— In vitro experiments used both a neuron-glia-microglia co-culture and a purified primary astrocyte culture under the same ultrasound protocol; both target terms are listed for this single exposure.exposures[0].in_situ— In vitro exposure is a cell-culture dish with no skull/tissue path; in_situ fields would ideally be null, but the paper's overall model_system also includes an in-vivo rodent exposure, so in_situ is recorded as not_reported rather than a value.