MiRNA‐224‐5p regulates the defective permeability barrier in sensitive skin by targeting claudin‐5

Background Sensitive skin is hypersensitive to various external stimuli and a defective epidermal permeability barrier is an important clinical feature of sensitive skin. Claudin‐5 (CLDN5) expression levels decrease in sensitive skin. This study aimed to explore the impact of CLDN5 deficiency on the permeability barrier in sensitive skin and the regulatory role of miRNAs in CLDN5 expression. Materials and methods A total of 26 patients were retrospectively enrolled, and the CLDN5 expression and permeability barrier dysfunction in vitro were assessed. Then miRNA‐224‐5p expression was also assessed in sensitive skin. Results Immunofluorescence and electron microscopy revealed reduced CLDN5 expression, increased miR‐224‐5p expression, and disrupted intercellular junctions in sensitive skin. CLDN5 knockdown was associated with lower transepithelial electrical resistance (TEER) and Lucifer yellow penetration in keratinocytes and organotypic skin models. The RNA‐seq and qRT‐PCR results indicated elevated miR‐224‐5p expression in sensitive skin; MiR‐224‐5p directly interacted with the 3`UTR of CLDN5, resulting in CLDN5 deficiency in the luciferase reporter assay. Finally, miR‐224‐5p reduced TEER in keratinocyte cultures. Conclusion These results suggest that the miR‐224‐5p‐induced reduction in CLDN5 expression leads to impaired permeability barrier function, and that miR‐224‐5p could be a potential therapeutic target for sensitive skin.