减轻脂肪肝缺血再灌注损伤的方法研究——基于库弗细胞内质网应激信号的调节

In recent years, with the shortage of donor, marginal liver was increased in the number of applications for transplantation, which led to liver protection related topics on the agenda. Fatty liver represented the main type of marginal donor and was sensitive to ischemia-reperfusion injury (IRI). So it was appreciated to find the effective approach to reduce fatty liver IRI. In our previous study, it was found that endoplasmic reticulum (ER)-stress in kupffer cells (KCs) was induced by IRI and then the activation of KCs promoted the transfer of IRI from metabolic injury to immune injury. In addition, based on the critical role of ER-stress in hepatic steatosis and the protective role of unfolded protein responses (UPR), it was speculated that ER-stress induced by steatosis resulted in activation of KCs, which worsened the following fatty liver IRI. However, UPR, slight ER-stress, was found to enhance cellular adaptive ability for resistance injury. So we also raised the hypothesis that the factors in ER-stress signal pass ways played various roles in fatty liver IRI. The study will address on investigating the effect of ER-stress in KCs on fatty liver IRI and finding the approach to attenuated IRI. The conclusions will be supported by positive and negative contrast argument based on vitro and vivo studies. This study will provide the step stone for the clinical application of protecting fatty liver from IRI in transplation.

近年随着供肝短缺，边缘供肝的应用增多，肝保护相关话题被提上日程。脂肪肝为边缘肝中主要类型，其对缺血再灌注损伤较为敏感，相关的保护方法甚少。我们的前期研究发现在肝缺血再灌注损伤中，内质网应激被激活，使库弗细胞活化，促进代谢性损伤转化为免疫性损伤。同时由于内质网应激在肝脂肪变过程中起重要作用。因此我们推测脂肪肝内库弗细胞在缺血再灌注损伤发生前已经处于内质网应激状态，这种改变可能提前激活库弗细胞，从而加重随之的缺血再灌注损伤。但理论上，轻度的内质网应激可增强细胞的适应能力，因此我们同时推测不同的内质网应激信号在脂肪肝缺血再灌注损伤中的作用不一样。本项目采用体内体外实验相结合，正反对比论证的方法，进行动物实验研究，旨在阐明库弗细胞内质网应激在脂肪肝缺血再灌注损伤中的作用，并通过干预内质网应激的信号通路，寻求减轻脂肪肝缺血再灌注损伤的方法，为防治肝移植过程中脂肪肝的缺血再灌注损伤奠定基础。

近年随着供肝短缺，边缘供肝的应用增多，肝保护相关话题被提上日程。脂肪肝为边缘肝中主要类型，其对缺血再灌注损伤较为敏感，相关的保护方法甚少。我们的前期研究发现在肝缺血再灌注损伤中，内质网应激被激活，使库弗细胞活化，促进代谢性损伤转化为免疫性损伤。同时由于内质网应激在肝脂肪变过程中起重要作用。因此我们推测脂肪肝内库弗细胞在缺血再灌注损伤发生前已经处于内质网应激状态，这种改变可能提前激活库弗细胞，从而加重随之的缺血再灌注损伤。但理论上，轻度的内质网应激可增强细胞的适应能力，因此我们同时推测不同的内质网应激信号在脂肪肝缺血再灌注损伤中的作用不一样。本项目采用体内体外实验相结合，正反对比论证的方法，进行动物实验研究。我们研究发现ER-stress三大主要信号通路中，IRE1α可促进KCs极性转化，即促进炎性KCs分化，加重肝炎性损伤。我们在研究脂肪肝缺血再灌注损伤时，发现脂肪肝组织中KCs处于ER-stress状态，加重脂肪肝对缺血再灌注损伤的敏感性，阻断IRE1α信号，抑制KCs向促进炎性KCs极性转化，减轻脂肪肝缺血再灌注损伤。研究ATF6信号通路时，发现ATF6激活可促进KCs分泌多种促炎细胞因子，阻断ATF6信号可以减轻肝损伤，同时也减轻急性肝损伤后肝纤维化发生，进一步研究发现，ATF6信号主要是通过抑制KCs分泌IL-1α，减轻肝星状细胞的活化起作用。了解KCs内ER-stress这一代谢信号对其活性的调控机制，有助于深入认识在急性肝损伤早期，代谢损伤信号向免疫损伤信号转化的机制。为开发新的干预手段提供理论依据。