Morinda officinalis extract exhibits protective effects against atopic dermatitis by regulating the MALAT1/miR‐590‐5p/CCR7 axis

Abstract Background Atopic dermatitis (AD) is a chronic inflammatory skin disease with a genetic predisposition, and the traditional Chinese medicine Morinda officinalis and its roots are characterized with anti‐inflammatory effects and have been used for the treatment of various disease. However, it is still largely unknown whether Morinda officinalis extract (MOE) can be used for the treatment of AD. Objectives In our study we aimed to determine whether MOE could ameliorate 2,4‐dinitrochlorobenzene (DNCB)‐induced AD and elucidate molecular mechanisms. Methods We established an AD mouse model by using DNCB. Skin pathological analysis and ELISA assay were used to detect the effect of MOE on the inflammation of AD model mouse skin and the expression changes of inflammatory factors, and further functional verification was performed in TNF‐α/IFN‐γ‐induced HaCaT cells. Results Our in vivo experiments confirmed that MOE remarkably reduced DNCB‐induced AD lesions and symptoms, such as epidermal and dermal thickness and mast cell infiltration and inflammatory cytokines secretion in the mice models. In addition, the underlying mechanisms by which MOE ameliorated AD had been uncovered, and we verified that MOE inhibited MALAT1 expression in AD, resulting in attenuated expression of C‐C chemokine receptor type 7 (CCR7) regulated by MALAT1‐sponge miR‐590‐5p in a competing endogenous RNA (ceRNA) mechanisms‐dependent manner, thereby inhibiting TNF‐α/IFN‐γ‐induced cellular proliferation and inflammation.