MicroRNA-205 promotes keratinocyte migration via the lipid phosphatase SHIP2.

microRNA-205 (miR-205) and miR-184 coordinately regulate the lipid phosphatase SHIP2 for Akt survival signaling in keratinocytes. As the PI3K-Akt pathway has also been implicated in regulating the actin cytoskeleton and cell motility, we investigated the role that these 2 miRNAs play in keratinocyte migration. We used antagomirs (antago) to reduce the levels of miR-205 and miR-184 in primary human epidermal keratinocytes (HEKs) and corneal epithelial keratinocytes (HCEKs) as well as direct SHIP2 silencing using siRNA oligos. Treatment of HEKs and HCEKs with antago-205 increased SHIP2 levels and impaired the ability of these cells to seal linear scratch wounds compared with untreated or irrelevant-antago treatments. In contrast, AKT signaling was enhanced and wounds sealed faster in HCEKs where miR-184 was suppressed, enabling miR-205 to inhibit SHIP2. Similar increases in migration were observed following direct SHIP2 silencing in HEKs. Furthermore, down-regulation of miR-205 resulted in an increase in Rho-ROCKI activity, phosphorylation of the actin severing protein cofilin, and a corresponding diminution of filamentous actin. The connection among miR-205, RhoA-ROCKI-cofilin inactivation, and the actin cytoskeleton represents a novel post-translational mechanism for the regulation of normal human keratinocyte migration.