miR-155 deficiency alleviates mouse skin inflammation through inhibiting the function of epidermal Langerhans cells / 中华微生物学和免疫学杂志

ABSTRACT

Objective@#To study the role of miR-155 in the development of allergic contact dermatitis in mice.@*Methods@#A mouse model of allergic contact dermatitis was induced by dinitrofluorobenzene (DNFB). Ear swelling was measured by caliper. Inflammatory changes in ears were observed with hematoxylin-eosin (HE) staining. Percentages of epidermal Langerhans cells (LC) and γδT cells in wild type (WT) and miR-155 knockout (miR-155KO) mice were detected by flow cytometry (FCM). Expression of major histocompatibility complex class Ⅱ (MHCⅡ) and costimulatory molecules on epidermal LC was tested by FCM to evaluate the maturation of LC in WT and miR-155KO mice. Fluorescein isothiocyanate-labeled Dextran (FITC-Dextran) was used to evaluate the phagocytotic abilities of LC by analyzing the percentages of FITC+ cells and mean fluorescence intensities (MFI) with FCM. Purified LC were co-cultured with antigen-specific CD4+ T cells sorted from OT Ⅱ mice for 72 h to analyze T cell proliferation by analyzing split peaks of CFSE. The co-culture system was stimulated with PMA and ionomycine, and blocked by Golgi stop at the same time to evaluate CD4+ T differentiation by analyzing the levels of IFN-γ and IL-17.@*Results@#Compared with WT mice, ear swelling was alleviated in miR-155KO mice. miR-155 deficiency had no significant influence on epidermal LC and γδT cells, but inhibited the maturation of in vitro-cultured LC through down-regulating the expression of MHC Ⅱ and costimulatory molecules. miR-155 deficiency did not affect the phagocytotic ability of LC, but inhibited the antigen-presenting ability of LC that could stimulate CD4+ T cell proliferation and differentiation.@*Conclusion@#miR-155 might play an important role in allergic contact dermatitis by enhancing the maturation and function of epidermal LC in mice.