S. epidermidis Rescues Allergic Contact Dermatitis in Sphingosine 1-Phosphate Receptor 2-Deficient Skin.

Recent studies have identified a subtype of the S1P-receptor family called sphingosine-1-phosphate receptor 2 (S1PR2), which plays a crucial role in maintaining the skin barrier. It has been observed that S1PR2 and Staphylococcus epidermidis (S. epidermidis) work together to regulate the skin barrier. However, the interaction between these two factors is still unclear. To investigate this, a study was conducted on healthy skin and allergic contact dermatitis (ACD) using 3,4-Dibutoxy-3-cyclobutene-1,2-dione (SADBE) on the ears of S1pr2fl/fl and S1pr2fl/flK14-Cre mice and using 1 × 106 CFU of S. epidermidis to examine its effects on the skin. The results showed that in S. epidermidis-conditioned ACD, the ear thickness of S1pr2fl/flK14-Cre mice was lower than that of S1pr2fl/fl mice, and mRNA expressions of Il-1β and Cxcl2 of S1pr2fl/flK14-Cre mice were lower than that of S1pr2fl/fl mice in ACD with S. epidermidis. Furthermore, the gene expression of Claudin-1 and Occludin in S1pr2fl/flK14-Cre mice was higher than that of S1pr2fl/fl mice in ACD with S. epidermidis. The study concludes that S. epidermidis colonization improves the skin barrier and prevents ACD even when S1P signaling malfunctions.