Oleic acid enhances keratinocytes differentiation via the upregulation of miR-203 in human epidermal keratinocytes

Background Oleic acid (OA) is an unsaturated free fatty acid (FFA) constituent of sebum. FFAs modulate keratinocyte differentiation. In this study, we determined whether OA affects keratinocyte differentiation in neonatal human epidermal keratinocytes (HEKn). Methods HEKn was grown in EpiLife medium. The cells were treated with various concentrations of OA. The expression levels of keratin 10 and involucrin were determined using Western blotting (for the proteins) and quantitative real time polymerase chain reaction (qRT-PCR) (for the mRNAs). Cytoskeletal changes were investigated by immunofluorescent staining. The levels of microRNA (miR)-203 were determined by stem-loop qRT-PCR. The effect of miR-203 on keratinocyte differentiation was evaluated using anti-miR-203. Results Treatment with OA promoted the expression of keratin 10 and involucrin, which are markers of spinous and granular layer keratinocytes, respectively. Treatment with OA also induced cell stratification and cytoskeletal changes such as the concentric ring organization of actin, a loss of planar polarity, and increased localization of epithelial cadherin (E-cadherin) at cell-cell contacts. OA increased the expression of miR-203, which is associated with keratinocyte differentiation, and reduced the expression of p63, a target of miR-203, in HEKn. Furthermore, transfection with anti-miR-203 suppressed the OA-induced expression of involucrin. Conclusions Oleic acid accelerates keratinocyte differentiation via the upregulation of miR-203 in HEKn under sub-confluent conditions.