摘要目的:探讨小分子miR-146a对表皮朗格汉斯细胞(Langerhans cells，LCs)稳态和功能的调控作用。方法:流式细胞术(flow cytometry, FCM)分选纯化新鲜分离及体外培养成熟后的表皮LCs，荧光定量PCR(quantitative PCR, qPCR)分析LCs中miR-146a的表达水平。FCM分析野生型和miR-146a条件性敲除(miR-146a conditional knockout，miR-146a cKO)小鼠表皮LCs数量差异。FCM分析组织相容性复合体Ⅱ(major histocompatibility complex Ⅱ，MHCⅡ)分子和共刺激分子(CD86、CD80)表达水平以及LCs吞噬Dextran-FITC的阳性细胞比例以评价miR-146a对LCs成熟和吞噬功能的影响。采用体内外试验分析miR-146a缺失的LCs刺激CD8 +OT-Ⅰ T细胞和CD4 +OT-Ⅱ T细胞增殖的能力以评价其对LCs的抗原提呈能力的影响。 结果:与新鲜分离的LCs比较，miR-146a在成熟LCs中表达水平显著上调。与野生型组比较，miR-146a缺失不影响表皮LCs的数量。分离表皮细胞在体外培养48 h后，miR-146a cKO小鼠与野生小鼠表皮LCs中MHCⅡ、CD86及CD80分子表达水平差异无统计学意义，且miR-146a缺失不影响LCs摄取抗原的能力，但miR-146a cKO小鼠表皮LCs刺激OVA蛋白特异性CD8 +OT-Ⅰ T细胞和CD4 +OT-Ⅱ T细胞增殖的能力显著增强。 结论:miR-146a不影响表皮LCs稳态、成熟及吞噬能力，但抑制LCs的抗原提呈功能。

abstractsObjective:To investigate the role of miR-146a in regulating the homeostasis and function of epidermal Langerhans cells (LCs).Methods:Fresh and in vitro cultured epidermal LCs were isolated and purified by flow cytometry (FCM). The expression of miR-146a in LCs was detected by quantitative PCR (qPCR). The percentages of epidermal LCs in wild-type (WT) and miR-146a conventional knockout (miR-146a cKO) mice were analyzed by FCM. The expression of major histocompatibility complex Ⅱ (MHCⅡ) and co-stimulatory molecules (CD86 and CD80) was analyzed by FCM to evaluate the effect of miR-146a on the maturation of LCs. The percentage of Dextran-FITC + LCs was detected by FCM to evaluate the effect of miR-146a on the phagocytic function of LCs. In vitro and in vivo experiments were used to analyze the ability of miR-146a-deficient and -sufficient LCs to stimulate the proliferation of CD8 + OT-ⅠT cells and CD4 + OT-Ⅱ T cells. Results:The expression of miR-146a was significantly increased in mature LCs than in the freshly isolated LCs. There was no significant difference in the number of epidermal LCs between wild-type (WT) and miR-146a cKO mice. After a 48 h culture in vitro, the expression of MHCⅡ, CD86 and CD80 in the epidermal LCs of miR-146a cKO mice was similar to that of WT mice. Moreover, miR-146a deletion had no significant influence on antigen uptake by LCs. However, miR-146a deficiency enhanced the antigen-presenting ability of LCs that could stimulate the proliferation of OVA-specific CD8 + OT-Ⅰ T cells and CD4 + OT-Ⅱ T cells. Conclusions:miR-146a had no influence on the homeostasis, maturation and phagocytosis of LCs, but enhanced the antigen-presenting function.