Emu oil alleviates atopic dermatitis-like responses by inhibiting Cdc42 signaling of keratinocyte

Emu oil is the oil extracted from the body fat of the Australian bird emu. Although previous studies have reported that emu oil has anti-inflammatory effects, the effect and mechanism of emu oil on the treatment of atopic dermatitis have not been reported. Here, 2, 4-dinitrofluorobenzene was used to induce atopic dermatitis-like appearance on the back skin of C57BL/6 mice. And then, the effect of emu oil in the atopic dermatitis treatment was evaluated. We found that emu oil reduced the transdermal water loss in the atopic dermatitis model. Additionally, the epidermal thickness treated with emu oil was significantly thinner. The number of mast cells and inflammatory cells were significantly decreased. The thymic stromal lymphopoietin (TSLP), which is secreted by keratinocyte, was decreased significantly after treatment. Moreover, the serum levels of cytokines TSLP, interleukin-4, interleukin-13, and immunoglobulin (Ig) E were decreased after emu oil treatment. Surprisingly, we found that the high level of Cdc42 expression in the atopic dermatitis, which was decreased after emu oil treatment. To detect the role of Cdc42 in atopic dermatitis, we constructed atopic dermatitis model in mice with sustained activation of Cdc42 signaling. Furthermore, we have confirmed that emu oil demonstrates anti-inflammatory effects in atopic dermatitis by inhibiting the expression of Cdc42 signaling in keratinocytes. In conclusion, we discovered a new role of Cdc42 in the development of atopic dermatitis, which mediated the therapeutic effect of emu oil on atopic dermatitis.