外泌体运载miRNA-150靶向TREM-1信号通路调节DCs的功能及在SLE中的作用和机制

Over-activation of dendritic cells (DCs) is the main cause of occurrence and development of systemic lupus erythematosus (SLE). We previously found that TREM-1 was highly expressed in DCs of SLE-like mice, which triggered the over-activation of DCs and was closely related to SLE. Nevertheless, the level of miRNA-150 was significantly down-regulated in SLE. Upregulation of miRNA-150 can regulate TREM-1 expression, but the specific molecular mechanism is still unclear. MicroRNAs can be easily removed and destroyed in vivo, which is the bottleneck restricting their clinical application. Exosomes can be used as an effective tool to deliver miRNAs in vivo. We intend to reveal the molecular mechanisms of TREM-1 expression in DCs regulated by miRNA-150. By modifying DCs with miRNA-150, exosomes encapsulating miRNA-150 (Exo-miRNA-150) derived from DCs will be isolated and purified, and their therapeutical effects and mechanisms in SLE-like mice will be explored. Furthermore, the correlation of Exo-miRNA-150 and TREM-1 as well as their pivotal roles in SLE will be detected and analyzed by combining clinical samples. This could provide new insights for the application of exosome-loaded miRNAs and the clinical treatment of SLE.

树突状细胞（DCs）的过度活化是系统性红斑狼疮（SLE）发生和发展的重要原因。我们前期发现SLE样小鼠体内DCs高表达TREM-1，该通路触发DCs过度活化并和SLE病情密切相关。而miRNA-150在SLE中则明显下调，上调miRNA-150后能调控TREM-1的表达，但具体的分子机制尚不清楚。miRNA在体内易被清除和破坏，是限制其临床应用的瓶颈，外泌体（exosomes）可作为体内传递miRNA的有效工具。本课题拟揭示miRNA-150调控DCs中TREM-1表达的分子机制；通过miRNA-150修饰DCs，分离纯化DCs来源的包裹miRNA-150的外泌体（Exo-miRNA-150），探究其对SLE样小鼠的治疗效果和机制；并结合临床样本检测和分析Exo-miRNA-150/TREM-1的相关性及在SLE中的重要作用，为外泌体运载miRNA的应用开发和SLE的临床治疗提供新的依据。

前期研究发现髓系细胞触发受体-1（TREM-1）参与多种炎症性自身免疫性疾病的发生发展。尽管如此，详细的潜在机制和靶向治疗效果仍未清楚，尤其是其在髓系树突状细胞（mDCs）和系统性红斑狼疮（SLE）中的研究尚待探索。在本研究中，我们筛选出TREM-1作为与SLE进展密切相关的关键基因之一，并鉴定出血清可溶性TREM-1（sTREM-1）作为SLE的有价值的诊断生物标志物。此外，TREM-1的激动剂激活可促进mDCs的活化和趋化能力，增加炎性细胞因子和趋化因子的产生，包括IL-6、TNF-α和MCP-1的表达升高。包括非编码RNA在内的表观遗传调控过程的紊乱会促进SLE的进展并产生复杂的临床表现。本研究中，我们发现狼疮小鼠的脾脏中显示出独特的miRNAs表达特征，其中miR-150是可以靶向TREM-1且表达变化最显著的miRNA。miRNA-150-5p模拟物的转染通过与TREM-1的3' UTR结合直接抑制TREM-1表达。研究发现，外泌体，特别是DCs衍生的外泌体（Dex），是针对自身免疫性疾病的有前途的诊断和治疗工具。我们获得了能够靶向和调节TREM-1通路的人工定向修饰的Dex（Dex-150），通过体内实验首次证明，Dex-150能有效改善狼疮症状。有趣的是，Dex-150通过TREM-1信号通路抑制淋巴器官和肾组织中mDCs的过度激活。总之，TREM-1是一个潜在的新治疗靶点，我们将Dex-150确定为减轻狼疮疾病的有效途径之一，这可归因于通过TREM-1信号通路抑制mDC的激活。我们的结果为TREM-1信号通路重塑树突状细胞的功能提供了新的见解，并为SLE的治疗提供了新策略。该项目已发表四篇SCI论文，并获得了两项专利的授权。