Claudin‐2 in hyperproliferative migrating keratinocytes and migration inhibition via siRNA knockdown

Abstract

AbstractClaudin‐2 is a tight junction protein found in various tissues including the epidermis of the skin. Intracellular signalling via claudin‐2 may have an effect on cell proliferation and migration. While the role of claudin‐2 in the epidermis has not been established, here we show an increase in claudin‐2 expression in hyperproliferative archival skin samples. To further examine the role of claudin‐2 in cell migration we examined its expression in cultured keratinocytes and found it was increased in wound margins in an in vitro scratch test assay. We then used a claudin‐2 knockdown assay using small interfering ribonucleic acid (siRNA) with a 77% transfection efficiency and decrease in claudin‐2 protein via Western blot analysis to examine cell migration, which was inhibited following claudin‐2 knockdown over a 5‐day period. Cells transfected with claudin‐2 siRNA also showed a decreased size compared to controls and a more diffuse staining pattern. Lastly we examined claudin‐2 expression in migrating keratinocytes by Western blot analysis and found a significant decrease in protein staining in scratch‐test assay cultures after 4 h, followed by a significant increase in claudin‐2 protein after 24 h. Taken together these results indicate a role for claudin‐2 signalling in proliferation and cell migration in the epidermis of the skin.