Integrin β1 subunit signaling is involved in the directed migration of human retinal pigment epithelial cells following electric field stimulation

Aims: Direct current electric fields (EFs) can induce directed cell migration in a wide variety of cells, and this has been proven to be of importance in wound healing. Here we observed the effects of EFs on cultured human retinal pigment epithelial (RPE) cells and explored the possible involvement of integrin β1 subunit signaling in the process.

Methods: Cultured human RPE cells were exposed to an EF at 5 V/cm for 3 h. The rate and directionality of cell migration were quantified. The distribution of integrin β1 subunit was measured by immunohistochemistry and the expression of integrin β1 subunit and phosphorylated focal adhesion kinase (FAK) was determined by PCR and Western blotting. Experiments were performed in the presence or absence of anti-integrin β1 subunit antibody.

Results: During exposure to an EF at 5 V/cm for 3 h, the separated human RPE cells and wounded RPE monolayer demonstrated a cathodal-directed migration. The distribution of integrin β1 subunit in the cells was also polarized to the cathode, and the expression in mRNA and its protein level were obviously increased. Furthermore, exposure to EFs of 5 V/cm triggered the phosphorylation of FAK in human RPE cells. In contrast, blocking of integrin β1 subunit suppressed the directed migration of RPE cells and reduced the activation of FAK in EFs.

Conclusions: These findings indicate that EF exposure results in directed migration of the separated RPE cells and RPE monolayer. These effects may partially act through the activation of integrin β1 subunit signaling.