Molecular and biophysical characterization of cultured DRG neurons in response to focused ultrasound
Elena Brunet, Thibaud Parpaite, Sungjae Yoo, Eric Debieu, Khaled Metwally, Serge Mensah, Pascale Malapert, Andrew Saurin, Olivier Macherey, Emilie Franceschini, Aziz Moqrich
Scientific Reports 2026 · 10.1038/s41598-025-34579-y
Abstract
Dorsal root ganglion (DRG) neurons have a wide range of functions, including touch, pain and itch. These neurons have recently emerged as promising targets for non-invasive focused ultrasound (FUS) neuromodulation. However, our understanding of the molecular and physical mechanisms underlying FUS-evoked responses in DRG neurons remains limited. Here, we explore the neuromodulatory effects of FUS on cultured DRG neurons using calcium imaging to track neural responses. We find that a 20-MHz FUS burst of 1-ms duration at an acoustic pressure of 5 MPa elicited calcium responses in 52% of DRG neurons. Single-cell RNA sequencing reveals that more than half of FUS-sensitive neurons belong to two subsets: the TH-expressing C low-threshold mechanoreceptors (C-LTMRs) and the MRGPRD-expressing C high-threshold mechanoreceptors (C-HTMRs), both of which express the Gαi-interacting protein (GINIP). This finding was further confirmed by using a ginip mouse model. We demonstrate that FUS excites both GINIP + and GINIP- neurons through membrane deformation, likely mediated by mechanosensitive ion channels. Our findings identify specific FUS parameters that activate distinct subsets of DRG neurons, opening new possibilities for using FUS to modulate DRG neuron activity.
Abstract via europepmc.
Exposures
Exposure 1: FUS stimulation of cultured DRG neurons (pressure/duration mapping; optimal stimulus = 5 MPa, 1 ms)
Target: dorsal root ganglion culture — “cultured dorsal root ganglion (DRG) neurons”
Device: Olympus / Panametrics · Olympus · V317-SM ✓
| Waveform | continuous | |
|---|---|---|
| Fundamental frequency (kHz) | 20,000 | ✓✓✓ |
| Pulse duration (ms) | not applicable | |
| Pulse repetition frequency (Hz) | not applicable | |
| Duty cycle (%) | not applicable | ⚑ |
| Sonication duration (s) | 0.0001, 0.001swept | ✓✓✓⚑ |
| Free-field pressure (kPa) | 4,000, 5,000swept | ✓✓✓ |
|---|---|---|
| Free-field Isppa (W/cm²) | 346, 536swept | ✓✓✓ |
| Free-field Ispta (W/cm²) | not reported | |
| 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 |
Each DRG neuron was sonicated with a single, uninterrupted 20-MHz sinusoidal tone burst (no internal pulsing/PRF) of positive pressure 4-5 MPa and duration 0.1-1 ms; each cell received only one such stimulus to avoid cumulative effects. The stimulus of 5 MPa/1 ms ('optimal FUS stimulus') activated 52% of DRG neurons (N=192 cells) and was used for downstream sc-RNA-seq and GINIP-mCherry experiments; a repeated series of 6-7 consecutive stimuli (varying pressure or duration) was used separately for high-speed deformation imaging.
Flags from extraction
n_subjects— The 14-mice cohort is used for the main pressure/duration dose-response mapping (Fig.1E-F); a separate cohort of 8 mice was used for single-cell RNA-seq, and additional unspecified numbers of mice were used for GINIP-mCherry and cell-deformation experiments; no single study-wide total is given.subject_unit— Ultrasound was delivered to individual cultured neurons (each receiving a single stimulus); subject_unit is recorded as 'animal' using the explicitly stated total mouse count for the main dose-response experiment, since no single total culture/dish or cell count spans the whole study.exposures[0].unspecified_domain.pressure_kpa— Value given as peak positive pressure p+ (4-5 MPa); the paper also reports peak negative pressure (e.g. -2.6 to -3.2 MPa in Table 1) for the same conditions, but only p+ is recorded here as the parameter the text uses to describe the dose-response sweep.exposures[0].timing.sonication_duration_s— Stimulus duration (0.1-1 ms) is reported as a single uninterrupted continuous-wave tone burst per cell; converted to seconds per the continuous-wave/single-burst convention, giving an unusually small sonication_duration_s range.exposures[0].timing.duty_cycle_pct— No PRF or repeated-pulse structure is used (single continuous tone burst per cell), so duty_cycle_pct is recorded as null rather than 100, since the concept of duty cycle does not straightforwardly apply to a one-off burst.