Ultrasound Stimulation Suppresses LPS-Induced Proinflammatory Responses by Regulating NF-κB and CREB Activation in Microglial Cells
Jia-Wei Chang, Meng-Ting Wu, Wen-Shin Song, Feng-Yi Yang
Cerebral Cortex 2020 · 10.1093/cercor/bhaa062
Abstract
The purpose of this study was to investigate the effects and underlying mechanisms of low-intensity pulsed ultrasound (LIPUS) against lipopolysaccharide (LPS)-induced neuroinflammation. BV-2 microglia subjected to LPS administration (1 μg/mL) were treated with LIPUS stimulation. The levels of inflammatory mediators and brain-derived neurotrophic factor (BDNF) were quantified using the western blot. The results showed that LIPUS stimulation promoted the associated cAMP response element-binding protein (CREB)/BDNF expression in the LPS-treated microglia. Meanwhile, LIPUS treatment effectively suppressed the LPS-induced production of tumor necrosis factor-α, interleukin-1β, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 in the microglial cells, in addition to inhibiting the LPS-induced expressions of toll-like receptor 4 and myeloid differentiation factor 88, as well as the LPS-induced activation of c-Jun N-terminal kinase and nuclear factor kappa B. Furthermore, LIPUS significantly decreased the Bax/Bcl-2 ratio in the microglia following LPS treatment. Our data indicated that LIPUS attenuated the proinflammatory responses as well as the decline in BDNF in LPS-treated microglia. This study provides a better understanding of how LIPUS stimulation regulates anti-inflammatory actions in microglia, providing further evidence suggesting that such stimulation may be regarded as a novel strategy for the treatment of neuroinflammation.
Abstract via crossref.
Exposures
Exposure 1: LIPUS stimulation of BV-2 microglia (and comparison astrocyte culture)
Target: cultured glia — “BV-2 microglial cells (cultured); CTX TNA2 astrocytes (cultured, comparison)”
Device: Mettler · Mettler Electronics · ME740 generator with ME7410 1-MHz plane transducer ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 1,000 | ✓✓✓ |
| Pulse duration (ms) | 5 | ✓✓✓ |
| Pulse repetition frequency (Hz) | 100 | ✓✓✓ |
| Duty cycle (%) | 50pulse duration × PRF gives 50% | ✓✓✓ |
| Sonication duration (s) | 300 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | 0.01, 0.02, 0.03swept | ✓✓✓⚑ |
| 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 sample of microglial cells was treated with multiple LIPUS stimulations by triple sonication. Each sonication lasted 5 min, with a 5-min interval between the first and second and between the second and third sonications, for a total sonication time of 15 min.
Flags from extraction
exposures[0].free_field.ispta_w_cm2— Paper states this as 'spatial average intensity' (SATA, averaged over the transducer face), not a spatial-peak measure; placed in ispta_w_cm2 as the closest schema field but the domain/measure type does not exactly match ISPTA.n_subjects— Paper reports only technical/biological replicate counts per assay (n=6 for most figures, n=4 for inhibitor experiments in Fig. 5) and never a total number of independent culture preparations for the study.