miR-146b抑制白介素10缺陷小鼠自发肠炎的作用机制

MiR-146b suppresses enteritis induced by IL-10 deficiency in mouse model

目的探讨miR-146b在小鼠IBD模型中的作用和机制,我们以白介素10(IL-10)敲除小鼠自发肠炎为模型,通过向小鼠腹腔内注射miR-146b mimic,评价miR-146b对IL-10^(-/-)缺陷小鼠自发肠炎的治疗效果。方法提取野生型(WT)和IL-10^(-/-)小鼠骨髓细胞,采用GM-CSF诱导成为巨噬细胞。首先用qPCR和原位杂交方法评估miR-146b在WT和IL-10^(-/-)巨噬细胞中的表达。将13周龄IL10^(-/-)小鼠分为scramble及治疗组,腹腔内注射scramble或miR-146b mimic。饲养4周后处死小鼠并取材做相应检测,用病理切片的方法评估病理炎症评分;采用流式细胞术、qPCR等方法检测各种炎症相关因子的变化。结果和WT小鼠相比,miR-146b在IL-10^(-/-)小鼠的表达明显下降(P<0.05);治疗组小鼠和scramble小鼠相比体重上升明显(P<0.05);miR-146b mimic可以明显改善小鼠肠道炎症(P<0.05);流式细胞术分析显示miR-146b mimic显著抑制肠系膜淋巴结和肠道固有层Th1细胞群、Th17细胞群的激活以及M1巨噬细胞的分化。结论 IL-10缺失导致miR-146b表达减少;miR-146b可以减轻IL10^(-/-)缺陷引起的自发性肠炎,其机制可能是通过抑制肠道M1型巨噬细胞分化而进一步减少Th1和Th17细胞激活。

Objective AimTo investigate the effects of miR-146b in inflammatory bowel disease, we successfully induced spontaneous enteritis by using IL-10 knockou （IL- 1 0 -’-） mice model. miR-146b mimics was injected intraperitoneally, in order to evaluate therapeutic effects of miR-146b for the spontaneous enteritis. Methods Bone marrow cells were isolated from wild-type （WT） and IL- 1 0 -’- mice, and differentiated by GM-CSF induction to macrophages. Hybridization in situ （ ISH） and qPCR were performed to detect miR-146b expression in the indicated. Female 13-week-old IL-10-/-mice were divided into 2 groups and injected with miR-146b mimics and scramble respectively. Mice were sacrificed at 4 weeks after injection. Severity of bowel inflammation was assessed by histopathological scoring. Flow cytometry and qPCR were performed to detect the level of inflammatory cytokines re-lated. Results Compared to WT mice, miR-146b expression in macrophages derived from IL-10-/- mice was significantly decreased （P 〈 0.05） . Individual weight of mouse by miR-146b mimics treatment was elevated markedly while no influence on scramble injection mice was observed. miR-146b treatment had significant effects on suppressing intestinal inflammation under microscope, compared with scramble injection （P 〈 0.05） . By flow cytometry analysis, miR-146b treatment could inhibit the activation of Th1 and Th17 cell populations, as well as the differentiation of M1 macrophages. Conclusion miR-146b is decreased in case of IL-10 deficiency. miR-146b treatment by intraperitoneal injection could suppress spontaneous enteritis induced by IL-10 deficiency, through inhibiting M1 macrophages differentiation to reduce activation of T1 and T17 cells.