基于胞外囊泡-线粒体途径探讨hUC-MSC在调节NETs形成减轻肝脏IRI中的作用机制研究

肝脏缺血再灌注损伤（HIRI）是影响肝移植术后患者预后以及移植物存活的重要因素，HIRI防治仍是移植领域急需解决的问题和挑战。既往研究表明肝脏浸润中性粒细胞胞外诱捕网（NETs）形成是造成HIRI的始动因素，抑制NETs可有效减轻肝脏损伤。我们前期已明确间充质干细胞（MSC）可调节中性粒细胞功能，减轻HIRI（Cell Death Dis, 2020; Adv Sci, 2020），申请人进一步通过预实验发现MSC可经胞外囊泡转运线粒体，调节中性粒细胞极性，抑制NETs形成。故由此提出科学假设：MSC是否通过胞外囊泡途径传递线粒体，重建应激状态下中性粒细胞内线粒体稳态，抑制中性粒细胞向N1炎性亚型极化，从而抑制NETs形成，改善小鼠HIRI？本课题拟通过体内、体外实验，从细胞器功能修复的新视角进一步阐明MSC防治HIRI的分子机制，为MSC治疗在肝移植器官保护中的临床转化提供理论依据。

Liver ischemia-reperfusion injury (HIRI) is an important factor affecting the prognosis of patients after liver transplantation and the survival of the graft. HIRI prevention and treatment is still an urgent problem and challenge to be solved in the field of transplantation. Previous studies have shown that the formation of hepatic infiltrating neutrophils extracellular trap NETs (NETS) is the initiating factor of HIRI, and inhibition of NETS can effectively reduce liver injury. We previously demonstrated that mesenchymal stem cells (MSC) modulate the neutrophil function and alleviate HIRI Cell Death Dis, 2020; Adv Sci, 2020), but the deep mechanics are still unclear. The applicant found that MSC could transport mitochondria through extracellular vesicles, regulate neutrophil polarity and inhibit the formation of NETS through preliminary experiments..Therefore, a scientific hypothesis is proposed: whether MSC can transfer mitochondria through extracellular vesicle pathway, reestablish mitochondrial homeostasis in neutrophils under stress state, inhibit neutrophils' polarization to N1 inflammatory subtype, thereby inhibiting the formation of NETS and improving HIRI in mice? This study intends to further clarify the molecular mechanism of MSC prevention and treatment of HIRI from a new perspective of organelle function repair through in vivo and in vitro experiments, so as to provide a theoretical basis for the clinical transformation of MSC treatment in the protection of liver transplantation organs.