Siglec-2调控肝Kupffer细胞TLR信号通路及其在肝脏缺血再灌注损伤中的作用和机制研究

Activation of Kupffer cells and production of inflammatory cytokines play important roles in the ischemia-reperfusion injury during liver transplantation. The regulation of Kupffer cells activation is an important question in the research of liver ischemia-reperfusion injury and liver transplantation. Siglec family members are important regulators in innate immune system, for example, Siglec-1 and Siglec-G can regulate host antiviral immune response. However, their roles in the regulation of Kupffer cell activation and liver ischemia-reperfusion injury are still unkonwn up to now. Hence, we screened the expression of Siglec family members in Kupffer cells, and found that Siglec-2 expression was significantly induced by liver ischemia-reperfusion injury. We then constrcued Siglec-2 conditional knockout mice, and hybridized with LyzM-Cre mice, thus generating macrophage specific Siglec-2 knockout mice. In these mice, liver inflammation and ischemia-reperfusion injury was significantly increased as compared with that of control mice, suggesting that Siglec-2 in Kupffer cells promotes liver ischemia-reperfusion injury. Based on these results, we intend to investigate the roles and underlying mechanisms of Siglec-2 in the regulation of liver ischemia-reperfusion injury, so as to suggest new mechanisms and therapeutic targets for liver transplantation.

肝脏Kupffer细胞的活化和炎症因子表达在肝脏缺血再灌注损伤(IRI)中发挥关键作用。Siglec家族在这一过程中可能发挥重要调节作用。我们前期利用基因芯片筛选发现Siglec-2对肝脏IRI具有较大影响，肝脏IR后肝Kupffer细胞中Siglec-2的表达显著增高。我们据此构建了肝Kupffer细胞特异性Siglec-2敲除小鼠，进一步研究发现Siglec-2肝Kupffer细胞敲除显著促进了肝脏IR损伤，并且与Toll样受体通路联系紧密。据此，本工作拟继续探寻小鼠肝脏IR模型中Kupffer细胞Siglec-2表达上调的分子机制，分析Siglec-2与TLR信号通路信号分子间的互相作用和对促炎细胞因子及趋化因子表达的调节作用；揭示Siglec-2对TLR下游信号通路调控作用的分子机制，为临床减轻肝缺血再灌注损伤、增加移植肝保存时间筛选新的靶标。

肝脏Kupffer细胞的活化和炎症因子表达在缺血再灌注损伤(IRI)中发挥关键作用。Siglec家族在这一过程中可能发挥重要调节作用。我们前期利用基因芯片筛选发现Siglec-2对肝脏IRI具有较大影响，肝脏IR后肝Kupffer细胞中Siglec-2的表达显著增高。我们据此构建了肝Kupffer细胞特异性Siglec-2敲除小鼠，进一步研究发现Siglec-2通过抑制TLR4信号激活在肝缺血再灌注损伤过程中发挥保护作用，揭示Siglec-2对TLR下游信号通路调控作用的分子机制，为临床减轻肝缺血再灌注损伤、增加移植肝保存时间筛选新的靶标。另外在研究过程中，我们亦发现冷诱导RNA结合蛋白(CIRP)通过调控铁死亡参与了调控器官IRI，进一步研究发现CIRP可通过ELAVL1调节铁死亡在肾缺血再灌注中发挥调节作用，阐明CIRP的具体作用机制，为缓解、治疗器官缺血引起的肾损伤提供一定的理论依据。目前形成了已经标注的论文4篇（SCI1篇和核心期刊论文3篇），资助3项专利（2项实用新型1项发明专利），硕士研究生2名（均已毕业）。本课题揭示了Siglec-2对TLR下游信号通路调控作用的分子机制，为临床减轻器官缺血再灌注损伤、促进修复、增加移植物存活时间筛选新的靶标，以及建立有效的治疗策略打下基础；另我们已经证实CIRB可能通过调节铁死亡参与肾缺血再灌注损伤，并且明确了CIRP通过调控ELAVL1参与铁死亡调节肾缺血再灌注的分子机制，为临床诊疗提供理论依据。