Stress Hormone Cortisol Damages the Skin Barrier by Regulating Tight Junctions

Psychological stress can affect the physiological condition of the skin and cause various cutaneous disorders. The stress hormone cortisol is secreted by various skin cells such as fibroblasts, keratinocytes, and melanocytes. Tight junctions (TJs) are cell–cell junctions that form a barrier in the stratum granulosum of mammalian skin. TJs can also affect other skin barriers and are affected by chemical, microbial, or immunological barriers. Stress can cause damage to the skin barrier. Interestingly, to our knowledge, there has not been any research demonstrating the involvement of TJs in this process. In this study, cortisol was used to treat keratinocytes to determine its role in regulating TJs. We found that cortisol damaged skin barrier function by regulating the gene expression and structure of TJ components. Cortisol also inhibited the development of the granular layer in a skin equivalent model. These results suggest that cortisol affects the skin barrier function by the regulation of TJs.