间充质干细胞通过干预NLRP3炎症小体介导的树突状细胞分化治疗肾脏缺血再灌注损伤的机制研究

Renal ischemia-reperfusion injury (IRI) is a major cause of acute renal injury, and the immune responses induced by dendritic cells (DCs) play a key role in renal IRI. In our preliminary study, we found that administration of mesenchymal stem cells (MSCs) may ameliorate renal IRI by inhibiting the maturation of DCs. However, deficiency of inducible nitric oxide synthase in MSCs may lead to decreased therapeutic effect, with the activation of NLRP3 inflammasome in renal DCs. Given that MSCs can induce the differentiation of regulatory DCs, and MSC-derived nitric oxide (NO) is an important inhibitor for the activation of NLRP3 inflammasome, we presume that NO released from MSCs may induce the differentiation of regulatory DCs by regulating the intracellular environment via inhibition of NLRP3 inflammasome activation, which ultimately suppress immune responses of renal IRI. In the present study, we will focus on the treatment of MSCs to renal IRI, and further investigate the mechanisms by which MSCs induce DC differentiation, as well as the important role of NLRP3 inflammasome in the differentiation of regulatory DCs after MSCs treatment. This project will provide a novel theoretical basis for MSC-based cellular immunotherapy.

肾脏缺血再灌注损伤（IRI）是引起急性肾损伤的重要因素，树突状细胞（DCs）引起的免疫应答在其中起关键作用。我们通过预实验发现，间充质干细胞（MSCs）可通过抑制DCs成熟治疗肾脏IRI，如MSCs缺失诱导型一氧化氮合酶，则其治疗肾脏IRI的效果明显减弱，并伴随肾脏DCs中NLRP3炎症小体的活化。鉴于MSCs可诱导调节性DCs的分化，且其所分泌的一氧化氮（NO）是抑制NLRP3炎症小体活化的重要因子，我们推测：MSCs可通过释放NO抑制DCs中NLRP3炎症小体的活化，从而改变DCs内环境，使其向调节性DCs分化，最终抑制肾脏IRI的免疫应答。因此，本项目拟以肾脏IRI中输注MSCs的治疗作用机制为主线，研究肾脏IRI中MSCs对DCs诱导分化的作用机理；NLRP3炎症小体介导调节性DCs分化的关键作用；MSCs抑制NLRP3炎症小体活化的分子机制，为MSCs的细胞免疫治疗提供理论依据。

肾脏缺血再灌注损伤（IRI）是引起急性肾损伤的重要因素，树突状细胞（DCs）引起的免疫应答在其中起关键作用。在该课题中，我们通过间充质干细胞（MSCs）对肾脏IRI进行治疗，发现了MSCs通过影响DCs分化进而改善IRI的重要机制。通过建立小鼠肾脏IRI模型并结合骨髓细胞诱导DCs的体外实验，我们发现MSCs的干预处理了抑制DCs中NLRP3炎症小体的活化，促进了MHCIIhiCD86lo调节性DCs的产生，通过释放TGF-β和IL-10，抑制了T细胞向肾脏中的迁移、活化以及Th2向Th1的转变，进而改善了肾脏IRI的病理损伤。进一步研究发现，MSCs来源的iNOS是其发挥免疫调节作用的重要因子，iNOS-/- MSCs对DCs中炎症小体的活化以IRI的发生并不显著抑制作用。这一研究使我们在一定程度上了解了输注MSCs在机体病理环境中的行为机理并发现了其重要调控靶点，初步掌握了通过免疫手段从而干预IRI发生的作用规律，为IRI的细胞免疫生物学治疗提供理论依据。