MSC通过miR-30a调控DCs产生IFN-α的机制研究

Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease and characterized by the production of autoantibodies and immune complexes that affects multiple organs. IFN-α plays a significant role in the occurrence and development of SLE and inhibiting the production of IFN-α can relieve the disease conditiion of SLE. Dendritic cells (DCs) is the most powerful professional antigen presenting cell in organism. Many studies have shown that the phenotypic and function of DCs are abnormal in SLE patients and lupus mice. Circulating dendritic cells mainly include myeloid DC (mDC) and plasmacytoid DC (pDC). Over the past two decades, numerous studies have suggested that IFN-α is mainly produced by pDC, but mDC can produce IFN-α too. In our previous study, MSC transplantion can alleviate the disease condition of SLE and reduce the level of IFN-α . MSC can suppress the differentiation and function of DCs. Many studies reported that MSC could secret many soluble factors, among which PGE2 plays a key role in MSC mediated the inhibition of production of IFN-α by DCs. We have found that the expression of miR-30a was lower in MSC of SLE patients than that of healthy people. miR-30a can upregulate the expression of COX2 which can promote the synthesis of PGE2. Also miR-30a can target the 3'UTR of IFNAR2 which is essential for the activition of IFN-I signaling pathway. However the mechanism on MSC regulates the synthesis of PGE2 is still unclear so far. Whether miR-30a secreted by MSC can target the IFNAR2 of DCs? This study will clarify the mechanism that how MSC affect the secretion of IFN-α by DCs via miR-30a and provide new theory for MSC transplantation in the treatment of SLE.

阻滞IFN-α的产生被认为可缓解SLE的发生及发展。循环的树突状细胞（DCs）主要包括髓系DC（mDC）和浆细胞样DC（pDC），pDC是主要产生IFN-α的细胞。我们前期发现SLE的间充质干细胞（MSC）低表达miR-30a，外源性正常的MSC高表达miR-30a，且能降低DCs表达IFN-α；miR-30a能上调MSC自身的PGE2合成基因COX2的表达，还可靶向IFNAR2。已知PGE2是MSC发挥免疫调节的关键因素，IFNAR2对DCs的IFN-α通路活化至关重要。推测miR-30a可通过PGE2和IFNAR2影响DCs产生IFN-α。可是迄今还不完全清楚miR-30a如何调节MSC产生PGE2？MSC分泌的miR-30a是否通过IFNAR2调控DCs产生IFN-α及其自反馈作用？本研究将探索MSC通过miR-30a调控DCs的机制，提出MSC改善自身免疫病的新理论。

本研究试图探索间充质干细胞（MSCs）通过 miR-30a 调控DCs的机制，提出MSCs 改善自身免疫病的新理论。我们发现高表达miR-30a不影响MSCs的表型、活力和凋亡，但能抑制CCNE2的表达，使细胞周期阻滞在G0/G1期；高表达miR-30a的MSCs能明显抑制DCs的成熟。进一步发现IL-1β能够明显上调IL-6、COX2和IL-8等的表达水平，而高表达miR-30a则显著抑制MSCs中这些因子的表达。miR-30a可结合到转化生长因子β激活激酶1结合蛋白3（TAB3）的3’UTR区，降低TAB3的mRNA和蛋白水平表达；高表达miR-30a能显著抑制IL-1β介导的NF-κB通路的活化，提示miR-30a可通过抑制TAB3的表达来调控MSCs的免疫调节功能。我们还发现IL-1β预处理MSCs具有有效缓解炎症性及免疫性疾病的作用，且IL-1β预处理MSCs（βMSCs）产生的外泌体与其母细胞MSCs的作用类似；βMSCs发挥免疫抑制功能的重要载体是MSCs分泌的外泌体；miR-146a是βMSCs外泌体发挥免疫抑制功能的关键分子。已知 SLE 患者易于罹患非霍奇金淋巴瘤（NHL），其中大部分为B淋巴瘤。我们发现非霍奇金淋巴瘤小鼠的脾脏及骨髓中G-MDSC和M-MDSC的显著升高，并且非霍奇金淋巴瘤的MDSC高表达miR-30a。我们证实 miR-30a 在 B细胞非霍奇金淋巴瘤中促进MDSC的分化及免疫抑制功能。此外，我们发现miR-494抑制MSCs对血管生成的调控潜能； MSCs通过调节Treg细胞降低AOM/DSS诱导的结肠炎相关结肠癌的发生；B淋巴细胞IFN-a中JAK1-STAT1通路过度活化与SLE发生发展的关系。综上所述，该研究明确了SLE患者MSCs的miR-30a表达，并分析其与DCs的关系，分析了miR-30a调控MSCs的机制；发现IL-1β预处理MSCs发挥免疫抑制功能的重要载体是其分泌的外泌体，且评价了IL-1β预处理MSCs分泌的外泌体对炎症性疾病的疗效，对于MSCs移植应用于临床提供了重要的理论依据。该项目发表论文14篇，其中SCI收录13篇。

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