mAChR拮抗通过调控Nr4a1/miR-124/IL-4Rα信号通路在变应性鼻炎中的作用和机制

Our previous studies demomstrated that the symptoms of allergic rhinitis (AR) and Th2 inflammation of nasal mucosa were be attenuated after inhibition of mAChR and vidian neurectomy. We have already applied the miRNAs and mRNAs microarray assay to detect the miRNAs and mRNAs profiles of nasal mucosa of AR mice model treated by anticholinergic drugs, and verified by quantitative RT-PCR. The results showed that expression of Nr4a1 and miR-124 was 73- and 22-fold increase, respectively, and expression of IL-4Rα was 23-fold decrease compared with controls. The hypothesis was proposed as "mAChR antagonist plays an anti-allergic inflammation by regulating the Nr4a1/miR-124/IL-4Rα signals in allergic rhinitis". This proposal is going to sort the CD4+ T cells, B cells, and dendritic cells of AR patients, and detect the expression level of mAChR, Nr4a1, miR-124, and IL-4α in these cells. Expression of IL-4α and downstream genes will be observed after activation and inhibition of mAChR, Nr4a1, miR-124 in cells. The interaction of these genes will be further confirmed by establishing the AR mice models of Nr4a1 and mAChR knockout mice and miR-124 transgenic mice. These experimental results will provide very strong evidences to elucidate the neuro-immuno modulatory mechanism of AR.

前期研究显示，乙酰胆碱受体(mAChR)抑制可显著减轻变应性鼻炎(AR)症状，减弱鼻粘膜Th2炎症反应。使用miRNA和mRNA微阵列芯片等技术对AR鼻粘膜进行研究发现，AR鼠模型鼻粘膜经抗胆碱药物处理2周，Nr4a1和miR-124表达上调了73倍和22倍，而IL-4Rα表达下调了23倍，提出“mAChR拮抗通过调控Nr4a1/miR-124/IL-4Rα及下游信号分子而发挥抗炎作用”的假说。本项目将以AR患者的CD4+T细胞、B细胞、树突状细胞及鼠AR模型为研究对象，观察AR患者这些免疫细胞的mAChR, Nr4a1, miR-124,IL-4Rα等基因的表达水平，分别以mAChR, Nr4a1, miR-124为靶基因，观察其被活化或抑制后，IL-4Rα及下游分子的表达变化。应用基因敲除及过表达小鼠模型诱发AR鼠模型，证实这些信号分子的相互关系。为阐述AR的神经免疫机制提供实验依据。

前期研究提示抑制乙酰胆碱受体3（m3）可减轻变应性鼻炎（AR）小鼠症状及鼻粘膜2型炎症反应，并使用miRNA和mRNA芯片技术筛选出miR-124-3p及IL4Rα基因。本项目拟研究miR-124-3p在AR中的作用及调控机制。体外细胞实验发现miR-124-3p模拟物显著降低小鼠脾脏淋巴细胞和人外周血PBMCs中IL-4Rα、p-STAT6及2型细胞因子水平，动物实验证实miR-124-3p激动剂和拮抗剂分别增加和降低IL-4Rα、IL-4表达水平，且miR-124-3p激动剂干预后AR小鼠脾脏淋巴细胞Th2百分比显著降低，AR小鼠的喷嚏和挠鼻数目显著降低，血清HDM特异性IgE（sIgE）水平下降，鼻粘膜嗜酸性粒细胞炎症反应显著减轻。本项目研究结果表明miR-124-3p可能通过IL-4Rα信号通路下调AR小鼠2型炎症反应，为变应性鼻炎的靶向治疗提供新的靶点。