Microvesicles Derived from Coagulase-Negative Staphylococci Promote the Gene Expression of Cornified Envelope Formation Factors in Human Epidermal Keratinocytes

Human skin provides a home to the skin commensal bacteria. They live symbiotically on the skin in a variety of roles. Therefore, the study of skin commensal bacteria has become a new target in the field of cosmetics. There are many publications about unbeneficial bacteria such as Cutibacterium acnes and Staphylococcus aureus. Recently several studies have been reported on microvesicles (MVs) derived from commensal bacteria. These reports strongly suggest that MVs are very important for understanding the functional nature of skin commensal bacteria. In this study, we focused on the coagulase-negative staphylococci (CoNS), which is thought to be beneficial to skin, including Staphylococcus epidermidis. We evaluated the effects of MVs derived from CoNS (CNS-MVs) on human epidermal keratinocytes. We found that the CNS-MVs were incorporated into keratinocytes and promoted gene expression of cornified envelope formation factors. These results suggest that CoNS improves the barrier function of epidermal keratinocytes via MVs. S. aureus-derived MVs (SA-MVs) induced gene expression of TNFα as an inflammatory mediator on keratinocytes, while CNS-MVs showed little effect. These data strongly suggest that MVs of CoNS can be considered as a potential active component of microbiome based topical skin care ingredients which support skin barrier improvement.