日本血吸虫虫卵外泌体Sja-miR-71a通过平衡Th17/Treg抗纤维化的作用及机制研究

Exosomes are extracellular vesicles secreted by living cells, carrying miRNAs that are involved in the occurrence and development of a variety of diseases. However, the role of immune regulation and liver fibrosis in schistosomiasis japonica are still unknown. Recently, we found that the exosomes derived from schistosoma japonicum egg can inhibit the activation of hepatic stellate cell, and this inhibition is related to the high expression of sja-miR-71a. Furthermore, sja-miR-71a can balance host Th17/Treg. Therefore, we propose that the high expression of sja-miR-71a in the exosomes of schistosoma japonicum egg play a role in anti-fibrosis by balancing Th17/Treg, leading to immune escape and persistent infection. This project will explore the role of sja-miR-71a balanced Th17/Treg in the anti-schistosomiasis liver fibrosis from in vivo and in vitro by Foxp3 knockout mice, exosomes were modified, recombinant adeno-associated virus, Real-time PCR Array, RNA interference and chromatin immunoprecipitation. Moreover, the target protein and regulated signal pathway of sja-miR-71a will clirafied to explore the molecular mechanism. This project will provide a new theoretical basis and therapeutic target for the treatment of schistosomiasis japonicum.

外泌体（exosomes）是活细胞分泌的一种胞外囊泡，其携带miRNA参与多种疾病的发生发展，但在日本血吸虫病免疫调节和肝纤维化中的作用及机制尚不明了。最近，我们发现日本血吸虫虫卵外泌体可以抑制肝星状细胞活化，该抑制作用与其高表达的Sja-miR-71a密切相关。进一步实验显示，Sja-miR-71a能够平衡宿主Th17/Treg。由此，我们推测虫卵外泌体Sja-miR-71a通过平衡Th17/Treg，发挥抗纤维化作用，从而逃避宿主免疫攻击，确保持续感染。本项目拟采用Foxp3敲除小鼠及外泌体改造、重组腺相关病毒、Real-time PCR芯片、RNA干扰、ChIP等技术，从体内外水平探讨Sja-miR-71a平衡Th17/Treg在抗肝纤维化中的作用，并进一步明确Sja-miR-71a的靶蛋白及参与调控的信号通路，深入探讨其分子机制，为血吸虫病的治疗提供新的理论依据和治疗靶点。

外泌体（exosomes）是活细胞分泌的一种胞外囊泡，其携带miRNA参与多种疾病的发生发展，但在日本血吸虫病免疫调节和肝纤维化中的作用及机制尚不明了。本项目中我们发现Sja-miR-71a高度富集于血吸虫虫卵外泌体， Sja-miR-71a具有抑制宿主纤维化反应的作用。进一步，我们阐明了Sja-miR-71a具有明显抑制宿主肝星状细胞激活，从而抑制宿主纤维化反应的作用，最终使日本血吸虫达到逃避宿主攻击的目的。同时，我们通过生物信息学分析，筛选了Sja-miR-71a相关靶基因。证实日本血吸虫虫卵来源外泌体Sja-miR-71a直接靶向Sema4D，日本血吸虫虫卵来源外泌体Sja-miR-71a通过抑制肝星状细胞活化从而抑制肝纤维化的作用是通过抑制Sema4D表达。同时，我们证实Sema4D的表达与α-SMA正相关， Sja-miR-71a通过Sema4D/TGF-β1 axis 及Sema4D/IL-13 axis抑制肝纤维化。进而阐明Sja-miR-71a调节Th1、Th2、Th17、及Treg细胞平衡，进而抑制肝纤维化。进一步，我们观察到日本血吸虫感染肝组织胞外囊泡（IL-EV）能够诱导中性粒细胞外捕获网（Neutrophil Extracellular Traps， NETs）形成，进而抑制血吸虫的生长发育，最终缓解病理进程并减轻肝纤维化，该作用与其高丰度表达的miR-142a-3p密切相关；而日本血吸虫可以分泌特异性抗原抑制NETs形成。本研究为进一步阐明宿主对血吸虫的杀伤机制及血吸虫免疫调节机制提供全新的科学观点。同时，也可为血吸虫病分子诊断及药物作用靶点提供新的分子标志物，为血吸虫病人的治疗提供新的途径。