AsianScientist (Feb. 9, 2018) – A research group in Japan has discovered that sound affects the gene expression of cells. They published their findings in PLOS ONE.
Cells, the fundamental units of life, are equipped with a variety of environmental recognition systems. Aside from substances such as chemical signals, they can recognize and respond to pressure, gravity, temperature and light. Although much research has been performed on specialized cells, little is known about cellular responses to audible sound.
In this study, scientists from Kyoto University’s Graduate School of Biostudies in Japan have shown that certain ‘mechanosensitive’ genes are suppressed when subjected to audible sound. Moreover, these effects vary depending on cell type.
The team conducted their experiments by exposing a variety of cells types to different sounds and performed gene expression analyses over time. Series of cells were placed in an incubator outfitted with a full-range loudspeaker. After several hours of exposure to sounds with specific frequencies, the expression levels of the target genes were analyzed.
“One such gene we examined helps in bone formation, and is known to be upregulated with low-intensity ultrasound pulses,” said Dr. Masahiro Kumeta of Kyoto University who led the study. “The other genes were associated with wound healing and the extracellular matrix.”
The team found that these mechanosensitive genes were suppressed by up to 40 percent after only one to two hours of exposure. Moreover, after the genes were suppressed, the downregulation of gene expression persisted for at least four hours.
The cellular responses were also dependent on waveforms and decibel levels. When exposing the cells to square or triangle waves, gene suppression was not as significant compared to sine waves on any tested frequency. Additionally, some genes did not show compounded suppression at higher decibels, while others were reduced even further. This indicated to the researchers that sound stimulation induces different responses in the cell.
The scientists also showed that such stimulations affect cells differently according to cell type. Cells that would eventually become bone or skeletal muscle showed the most suppression, while cells that had already differentiated had almost no response.
“Our research has found that audible sound stimulation leads to specific genetic responses,” said Professor Shige H. Yoshimura of Kyoto University who is a senior author of the study. “These data also show that at least two mechanisms are involved: transcriptional control and RNA degradation. Both are key players in controlling how much proteins are made in the cell.”
The team is planning to continue testing their hypotheses, at the same time searching for other genes that have been affected, such as ones that may have been upregulated by audio stimulation.
“Further studies using different sounds, cells and experimental setups are sure to uncover more of this novel relationship between life and sound,” added Kumeta.
“In addition to the cellular level, we will also focus on tissue- and organism-level effects to investigate the biological significance of sound response in living systems,” said Yoshimura.
The article can be found at: Kumeta et al. (2018) Cell Type-specific Suppression of Mechanosensitive Genes by Audible Sound Stimulation.
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Source: Kyoto University; Photo: Eiri Ono.
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