Ultrasound Modulates Piezo1-Mediated Mechanotransduction in Neuro2A Cells

Abstract

Mechanotransduction has been demonstrated to play an important role in mediating cellular or tissue adaption. Ultrasound stimulation can trigger mechanosensing bioeffects in several biological systems through the mechanical pressure wave. It is well documented that the ultrasound-induced mechanosensing bioeffects have been widely applied for several kinds of noninvasive therapies, such as bone fracture healing, lithotripsy, nerve regeneration, deep-brain stimulation for brain disorder treatment, or noninvasive functional neurosurgery. However, the gene regulatory mechanism of ultrasound-induced mechanosensing bioeffects is not fully understood. Recently, Piezo1 was characterized as the mechanically activated ion channels through cell-attached patch clamp assay, poke assay, atomic force microscopy-based assay, high-pressure perfusion assay, or stretch assay. It also has been demonstrated that Piezo1 channel activity was mediated in a substrate stiffness-, shear stress-, osmotic pressure-, or compression-dependent manner. However, whether Piezo1 can play a role in ultrasound-induced mechanotransduction pathway is not clear. Here, we applied a technique by using focused ultrasound to deliver a non-contact mechanical stimulus to cells labeled fluorescent calcium dye. Our study demonstrated that the calcium influx was transiently increased in Piezo1-overexpressed Neuro2A cells following the ultrasound stimulation. Using siRNAs against Piezo1 in Neuro2A cells showed decreased calcium influx following the ultrasound stimulation. Compared to cells treated with or without ultrasound, cell viability was not affected. In conclusion, our study demonstrated that ultrasound could emerge as a way to deliver mechanical force to trigger Piezo1 channel activity by using our experimental system. The system can serve as a basis for further investigation of the Piezo1-mediated mechanotransduction mechanism in cells following ultrasound stimulation.