Electric Fields Guided HaCaT Cell Migration Are Mediated By EGFR Through P38MAPK/Akt Pathway

Background Cells may sense small directed current electric fields（EFs）,generated by interruption of trans-epithelial potential in wound,and migrate toward the wound center to promote wound healing.The phenomenon that cells may sense small directed electrical fields and migrate toward cathode or anode along electric field is called electrotaxis.The molecular mechanism behind electrotaxis remains unclear.The epidermal growth factor receptor（EGFR）,one of the receptor tyrosine kinases（RTKs）,is a member of the ErbB/HER family which play an important role in wound healing.Previous studies have shown that electric fields may upregulate EGFR expression and polarize its distribution in cells.In this study,the signaling transduction involved EGFR,p38MAPK and Akt were investigated with HaCaT cell.The role of Ca²⁺channel STIM1（stromal interaction molecule 1）,in electrotaxis was studied as well.Methods The small directed EF with the physiological strength was applied to mimic the endogenous electric field.The cell migration was recorded by image system.The AG1478,SB203580 and MK-2206 were used to investigate the roles of the EGFR,p38MAPK and Akt in cell electrotaxis;Western blot was applied to examine the expression and activation of EGFR,p38MAPK,and Akt in response to electric field.The siRNA technique was applied to explore the effect of STIM1 on cell electrotaxis.Results 1)HaCaT cell migrated toward the anode under electric field（100m V/mm）;2)The inhibition of EGFR by AG1478 obviously impaired（P<0.001）the directedness of HaCaT cell migration under EFs,while the migration speed were not affected.3)Inhibition of both p38MAPK and Akt activity impaired the electrotaxis of HaCaT cell（P<0.001）;4)Western blot results showed that EGFR may upregulated the phosphorylation of Akt by activating of p38MAPK during cell migration under EF treatment;5)Knock-down of STIM1 expression using siRNA had no significant effect on the electrotaxis of HaCaT cell.Conclusions Electric fields guided HaCaT cell migration are mediated by EGFR through p38MAPK/Akt pathway,and interfering with STIM1 expression does not affect the electrotaxis of HaCaT cell.