半乳糖凝集素9介导MSCs抑制SLE NETosis的机制研究

Neutrophils (Neu) release neutrophil extracellular traps (NETs) via NETosis. NETs, as autoantigens, induce autoantibody production, which play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Previous study showed that reduced NETs production and death of SLE Neu after coculturing with MSCs, implying that MSCs remarkably prevented SLE Neu undergoing NETosis. Yet the underlying mechanisms are not clear. Our preliminary experiments found that significantly higher galectin-9 (Gal-9) was detected in MSCs after coculturing with SLE neutrophils. Besides, neutrophils expressed the receptors of Gal-9. Therefore, we hypothesize that Gal-9 mediates MSC suppression of SLE NETosis，thus reducing autoantibody production and ameliorating SLE. In this study, the role of Gal-9/Gal-9 receptor pathway mediated suppression of NETosis by MSCs will be clarified through in vitro and in vivo experiments. Furthermore, we will explore the effects of Gal-9/Gal-9 receptor on NETosis related pathways. This study will not only reveal the molecular mechanism of MSCs regulating NETosis, but also provide novel theoretical basis for the clinical application of MSC treatment in SLE.

中性粒细胞（Neu）通过NETosis释放含多种自身抗原成分的胞外诱捕网（NETs），诱导自身抗体产生，在系统性红斑狼疮（SLE）发病过程中起重要作用。前期发现SLE患者Neu与间充质干细胞（MSCs）共培养后，NETs的产生及Neu的死亡明显减少，提示MSCs能抑制SLE NETosis发生，但具体机制不清楚。我们检测共培养后MSCs中半乳糖凝集素9（Gal-9）表达显著增加，且Neu高表达Gal-9受体。基于此提出科学假说：Gal-9介导MSCs抑制SLE NETosis，从而减少自身抗体产生缓解SLE病情。本项目将通过体内外实验，探究MSCs通过Gal-9/Gal-9受体通路对SLE NETosis的抑制作用，解析Gal-9/Gal-9受体对SLE NETosis相关通路的影响。本研究揭示MSCs抑制SLE NETosis的分子机制，为临床MSCs移植治疗SLE提供新的理论基础。

中性粒细胞（Neu）死亡增多，释放含多种自身抗原成分，诱导自身抗体产生，在系统性红斑狼疮（SLE）发病过程中起重要作用。间充质干细胞（MSC）治疗SLE有效，但对SLE Neu死亡是否有调控作用及具体机理尚不明确。本项目中，我们发现MSC体外可显著减少SLE患者Neu的死亡，并抑制髓过氧化物酶（MPO）的表达；结合前期研究，我们筛选出半乳糖凝集素9（Gal-9）可能参与MSC调控SLE Neu；沉默MSC中Gal-9的表达或在共培养体系中加入Gal-9的拮抗剂，MSC对SLE患者Neu死亡的抑制作用显著减弱；动物体内实验发现，MSC移植狼疮鼠可显著减少外周血及脾脏Neu的死亡，并减少肺脏及肾脏Neu的浸润，而Gal-9沉默的MSC（siGal-9 MSC）则不能抑制Neu的死亡，也不能减少其在器官中的浸润；siGal-9 MSC也不能显著减少狼疮鼠尿蛋白的水平和改善肾脏病理损伤。这些结果表明MSC体内外均可通过Gal-9抑制SLE Neu死亡，从而发挥治疗作用。本研究揭示了MSC通过调控Neu死亡治疗SLE的新机制，为临床MSCs移植治疗SLE提供了新的理论基础。