PIEZO1 Channel is Involved in Electric Field Guided Cell Migration / 生物化学与生物物理进展

ObjectiveDisruption of epithelial layer may instantaneously induce the generation of endogenous electric fields, which was proved to play an important role in guiding the cell migration and promoting wound healing. PIEZO1 is a kind of mechanic sensitive channel, may be regulated by voltage, is proved to involve in chemotactic migration of cells and play an important role in the process of wound healing. In this paper, the role of PIEZO1 and its downstream proteins FAK and integrin β1 in the electric field guided cell migration were investigated by HaCaT cells (human immortalized keratinocyte). MethodsCell migration was tracked by Living Cell Imaging System in directed current (DC) electric field (EF). Inhibitors and RNAi techniques were applied to study the function of PIEZO1 and other related proteins in electric fields. Western blot was used to detect the expression and phosphorylation levels of integrin β1 and FAK in electric field guided migration under EF stimulation. ResultsPiezo1 RNAi as well as Ruthenium red and GsMTx4 treatment all significantly inhibited the electrotaxis of HaCaT cells. Electric field stimulation with GsMTx4 treatment alone increased FAK phosphorylation level and the expression of integrin β1. Electric field promoted the expression level of integrin β1 and the phosphorylation level of FAK. Inhibiting the expression of PIEZO1 by RNAi significantly attenuated the phosphorylation level of FAK under EF stimulation. Inhibition of integrin β1 and FAK by inhibitor significantly decrease the electric field guided cell migration. ConclusionPIEZO1 as well as integrin β1 and FAK are involved in the electric field guided cell migration of HaCaT cells. Electric field signals regulate the expression of integrin β1 and the activation of FAK through PIEZO1-mediated signal pathway to orchestrate cell migration.

Phosphatidylinositol 3-kinases Play a Suppressive Role in Electrotaxis of Dictyostelium Cells Through Akt and ERK / 生物化学与生物物理进展

ObjectivePhosphatidylinositol 3 kinases (PI3Ks) play an important role in cell directional movement by regulating F-actin. However, the structure and function of PI3Ks are complex. The role of PI3Ks in cell electrotaxis is not fully understood. Therefore, in this study, the model organism Dictyostelium discoideum cells were used as experimental materials to explore the role of PI3K1 and PI3K2 in electrotaxis. MethodsFirstly, PI3K1 coding gene pikA knockout mutant and PI3K2 coding gene pikB knockout mutant were constructed by CRISPR/Cas9 system. Secondly, two mutants were placed in a DC electric field with a strength of 12 V/cm and the electrotaxis were analyzed. ResultsData analysis showed that the direction index of wild-type cells in DC electric field was (0.86±0.03), while the direction index of pikA- and pikB- mutants in DC electric field was (0.95±0.02) and (0.94±0.03), respectively. In addition, the average trajectory speed of wild-type cells in the electric field was (3.34±0.08) μm/min, while the average trajectory speed of pikA- and pikB- mutants were (4.85±0.20) μm/min and (5.48±0.15) μm/min, respectively. The t test showed that there were significant differences in the directedness index and speed between the mutant and wild type. Western blot results showed that both phosphorylated Akt and phosphorylated ERK were significantly increased in pikA- and pikB- mutants. ConclusionPI3K1 and PI3K2 may inhibit the electrotaxis of Dictyostelium discoideum cells by increasing the activity of Akt and ERK.

Electrotaxis of alveolar epithelial cells in direct-current electric fields / 中华创伤杂志(英文版)

PURPOSE@#This study aims to elucidate the electrotaxis response of alveolar epithelial cells (AECs) in direct-current electric fields (EFs), explore the impact of EFs on the cell fate of AECs, and lay the foundation for future exploitation of EFs for the treatment of acute lung injury.@*METHODS@#AECs were extracted from rat lung tissues using magnetic-activated cell sorting. To elucidate the electrotaxis responses of AECs, different voltages of EFs (0, 50, 100, and 200 mV/mm) were applied to two types of AECs, respectively. Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs. Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration. To further demonstrate the impact of EFs on the pulmonary tissue, the human bronchial epithelial cells transformed with Ad12-SV40 2B (BEAS-2B cells) were obtained and experimented under the same conditions as AECs. To determine the influence on cell fate, cells underwent electric stimulation were collected to perform Western blot analysis.@*RESULTS@#The successful separation and culturing of AECs were confirmed through immunofluorescence staining. Compared with the control, AECs in EFs demonstrated a significant directionality in a voltage-dependent way. In general, type Ⅰ alveolar epithelial cells migrated faster than type Ⅱ alveolar epithelial cells, and under EFs, these two types of cells exhibited different response threshold. For type Ⅱ alveolar epithelial cells, only EFs at 200 mV/mm resulted a significant difference to the velocity, whereas for, EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference. Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11.@*CONCLUSION@#EFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects, which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

A simple microfluidic chip technology for assaying electrotaxis of cancer cells / 军事医学

Objective To develop a simple microfluidic chip technology for analyzing the electrotaxis of cancer cells . Methods The basic structure of the proposed microfluidic electrotaxis chip included a straight microchannel and liquid storage pools located on both sides of the microchannel .Two platinum electrodes were inserted into the liquid pools to create a controllable direct current ( DC ) field in the microchannel .The distribution and strength of the DC field in the microchannel was analyzed by the finite element analysis software COMSOL multiphysics and experiment tests .Finally, the electrotactic behavior of the rhabdomyosarcoma RD cells in the DC field of different strength was characterized using the accumulated distance, average velocity, x forward migration index ( xFMI) and y forward migration index ( yFMI) as quantitative parameters.Results The results of element analysis and experiments showed that the structure of the designed microfluidic electrotaxis chip was able to guarantee a uniform and strength-controllable DC field in the microchannel .The experiment of cell electrotaxis showed that the RD cells migrated toward the anode of the DC field .Meanwhile , the values of xFMI and accumulated distance for RD cells increased with the enlargement of the DC field , with the strength ranging from 188 to 1320 V/m.Conclusion The microfluidic chip technology developed in this paper for assaying the electrotaxis of cancer cells is simple and easily implementable , and it can be used for studies of the electrotactic behavior and underlying mechanisms of various cancer cells and normal cells in the future .