Polarization of ADAM17-driven EGFR signalling in electric field-guided collective migration of epidermal sheets

Endogenous electric field is considered to play an important role in promoting collective migration of epidermis to the wound centre. However, most studies are focused on the effect of bioelectric field on the movement and migration of single epithelial cell; the molecular mechanisms about collective migration of epidermal monolayers remain unclear. Here, we found that EFs dramatically promoted the collective migration of HaCaT cells towards the anode, activated the sheddase activity of ADAM17 and increased the phosphorylation level of EGFR. Moreover, EGFR phosphorylation and HB-EGF shedding level were significantly decreased by the ADAM17 inhibitor TAPI-2 or siADAM17 under EFs, which subsequently attenuated the directed migration of HaCaT sheets. Notably, the inhibition of EF-regulated collective migration by siADAM17 was rescued by addition of recombinant HB-EGF. Furthermore, we observed that F-actin was dynamically polarized along the leading edge of the migrated sheets under EFs and that this polarization was regulated by ADAM17/HB-EGF/EGFR signalling. In conclusion, our study indicated that ADAM17 contributed to the collective directional movement of the epidermal monolayer by driving HB-EGF release and activating EGFR under EFs, and this pathway also mediated the polarization of F-actin in migrating sheets, which is essential in directional migration.