Background and aims Skin injury is the second most common clinical manifestation in patients with systemic lupus erythematosus (SLE). Oestrogen may affect the onset and development of SLE. This study was undertaken to elucidate the role of oestrogen in the development of SLE skin injury.

Methods We investigated the role of oestrogen and its membrane receptor GPER1 in SLE-related skin injury in mice treated with SLE serum in vivo, and monocytes from mouse spleen in vitro.

Results We found that skin injury induced by SLE serum was more severe in female mice and required monocytes. E2 promoted these effects through the membrane receptor GPER1 located in lipid rafts and that inhibition of lipid rafts and GPER1 suppressed SLE serum-induced skin inflammation and expression of inflammatory molecules.

Conclusions We conclude that oestrogen promotes the development of skin injury induced by SLE serum through the membrane receptor GPER1 and that lipid rafts play an important role in the regulatory effect of GPER1 in SLE skin inflammation.