摘要
Mechanobiological stimuli,such as low-intensity pulsed ultrasound(LIPUS),have been shown to promote bone regeneration and fresh fracture repair,but the fundamental biophysical mechanisms involved remain elusive.Here,we propose that a mechanosensitive ion channel of Piezo1 plays a pivotal role in the noninvasive ultrasound-induced mechanical transduction pathway to trigger downstream cellular signal processes.This study aims to investigate the expression and role of Piezo1 in MC3T3-E1 cells after LIPUS treatment.Immunofluorescence analysis shows that Piezo1 was present on MC3T3-E1 cells and could be ablated by shRNA transfection.MC3T3-E1 cell migration and proliferation were significantly increased by LIPUS stimulation,and knockdown of Piezo1 restricted the increase in cell migration and proliferation.After labeling with Fluo-8,MC3T3-E1 cells exhibited fluorescence intensity traces with several high peaks compared with the baseline during LIPUS stimulation.No obvious change in the fluorescence intensity tendency was observed after LIPUS stimulation in shRNA-Piezo1 cells,which was similar to the results in the GsMTx4-treated group.The phosphorylation ratio of ERK1/2 in MC3T3-E1 cells was significantly increased(P<0.01)after LIPUS stimulation.In addition,Phalloidin-iFluor-labeled F-actin filaments immediately accumulated in the perinuclear region after LIPUS stimulation,continued for 5 min,and then returned to their initial levels at 30 min.These results suggest that Piezo1 can transduce LIPUS-induced mechanical signals into intracellular calcium.The influx of Ca2+serves as a second messenger to activate ERK1/2 phosphorylation and perinuclear F-actin filament polymerization,which regulate the proliferation of MC3T3-E1 cells.
基金
supported by the National Institute of Health(R01AR052379 and R01AR61821,YXQ)
GZ is partially supported by a fellowship from the Dental School of the Chinese Medical University during his studies at Stony Brook University.
