清道夫受体A调控中性粒细胞诱导补体活化在暴发性肝炎发生发展中的作用研究
发布时间：2018-08-31 18:44
【摘要】：暴发性肝炎(Fulminant hepatitis,FH)是一种罕见的急性疾病,伴随肝功能急速恶化,肝细胞大面积坏死甚至肝性脑病等特征。尽管近年来对FH的治疗方法有所进步,但其仍可导致较高的死亡率。临床证据表明,在人类FH进程中纤维蛋白大量沉积和微脉管血栓形成是造成肝细胞损伤的重要原因。此外,免疫细胞的激活和后续产生的促炎细胞因子(例如TNF-α,IL-1β,IL-6和IFN-γ)也在促进FH疾病进展中发挥重要作用。因此,探讨FH的免疫学发病机制将为研究FH更普遍和有效的治疗提供思路。清道夫受体A(ScavengerReceptor A,SRA)主要表达在髓系细胞表面,如巨噬细胞和树突状细胞。Ozment等发现SRA也能表达在循环和骨髓中的中性粒细胞表面,并在受到TLR2激动剂刺激后表达上调。SRA作为天然免疫中的模式识别受体(pattern recognition receptor,PRR),能够识别广泛的“自己”和“非己”配体,在机体抵御病原微生物的侵入和维持免疫稳态中发挥重要作用。越来越多的研究表明,SRA还可作为免疫调控分子参与多种炎症性疾病的发病进程,其免疫调控作用可能与其内吞作用相互独立。我们发现SRA在HBV感染的暴发型肝炎病人的肝组织中高表达。然而,目前尚未见SRA在暴发性肝炎中的免疫调节作用研究。鼠肝炎病毒(Mouse hepatitis virus,MHV)是单正链RNA病毒,可用于构建敏感小鼠的肝炎、肠炎或脑炎模型。Balb/c和C57/BL6小鼠腹腔感染嗜肝性MHV病毒(如MHV-3和MHV-A59)后可在肝血窦形成血栓,肝细胞大量坏死,因此可以作为研究人类FH的有效模型。与野生型(wild-type,WT)小鼠相比,SRA-/-小鼠对MHV-A59诱导的暴发性肝炎耐受,并伴随着肝脏炎症反应的减轻和血清中纤维介素(fibrinogen-like protein 2,Fgl2)下降;使用C5aR拮抗剂后,小鼠肝损伤明显减轻,并且WT小鼠与SRA-/-小鼠肝脏炎症反应和肝损伤差异消失,这表明在FH进程中SRA通过上调C5a表达加剧MHV的炎症效应和肝损伤。研究发现,中性粒细胞表达的SRA调控WT小鼠与SRA-/-小鼠病毒感染所致肝损伤的差异;SRA通过促进MHV-A59刺激中性粒细胞内TAK1磷酸化上调ERK的激活进而影响中性粒细胞胞外诱捕网(neutrophil extracellular traps,NETs)的形成和中性粒细胞弹性蛋白酶(neutrophil elastase,NE)的释放,随后,NE诱导C5裂解为C5a发挥促炎效应;小鼠体内使用NE的抑制剂西维来司钠后,病毒感染WT小鼠和SRA--小鼠所致肝损伤和C5a的表达量无显著性差异;并且我们发现阻断SRA可以减轻MHV-A59所致的肝损伤。综上,SRA调控MHV-A59诱导的中性粒细胞NET形成,进而促进C5a产生和后续的肝损伤。抑制SRA可能为FH免疫学治疗提供新的策略。
[Abstract]:Fulminant hepatitis (Fulminant hepatitis,FH) is a rare acute disease characterized by rapid deterioration of liver function, massive necrosis of hepatocytes and even hepatic encephalopathy. Despite advances in treatment of FH in recent years, it can lead to higher mortality. Clinical evidence shows that fibrin deposition and microvascular thrombosis are important causes of hepatocyte injury in human FH process. In addition, the activation of immune cells and the subsequent production of pro-inflammatory cytokines (such as TNF- 伪, IL-1 尾, IL-6 and IFN- 纬) also play an important role in promoting the progression of FH. Therefore, the study of immunological pathogenesis of FH will provide ideas for the study of more general and effective treatment of FH. Scavenger receptor A (ScavengerReceptor Agna was mainly expressed on the surface of myeloid cells, such as macrophages and dendritic cells. Ozment found that SRA could also be expressed on the surface of neutrophils in circulation and bone marrow. After stimulation with TLR2 agonists, the expression of. SRA was up-regulated as a pattern recognition receptor (pattern recognition receptor,PRR) in innate immunity, which could recognize a wide range of "self" and "non-hexane" ligands. It plays an important role in resisting the invasion of pathogenic microorganisms and maintaining immune homeostasis. More and more studies have shown that SRA can also participate in the pathogenesis of various inflammatory diseases as an immunomodulator, and its immune regulation may be independent of its endocytosis. We found high expression of SRA in liver tissues of HBV infected fulminant hepatitis patients. However, the immunomodulatory effect of SRA in fulminant hepatitis has not been studied. Murine hepatitis virus (Mouse hepatitis virus,MHV) is a single positive strand RNA virus. It can be used to construct hepatitis, enteritis or encephalitis model. Balb / c and C57/BL6 mice are infected with hepatophilic MHV virus (such as MHV-3 and MHV-A59). Therefore, it can be used as an effective model for the study of human FH. Compared with the wild-type (wild-type,WT) mice, SRA-r- mice were resistant to fulminant hepatitis induced by MHV-A59, accompanied by the reduction of inflammatory reaction in the liver and the decrease of fibrinogen-like protein _ 2 Fgl2 in serum, and the liver injury was significantly alleviated by the use of C5aR antagonist. Moreover, the difference between WT mice and SRA-/- mice in liver inflammation and liver injury disappeared, which indicated that SRA increased the inflammatory effect and liver injury of MHV by up-regulating C5a expression during the FH process. The study found that, The difference of SRA expression of neutrophils in regulating liver injury induced by virus infection in WT mice and SRA-/- mice. SRA promotes MHV-A59 stimulation of TAK1 phosphorylation in neutrophilic granulocytes to up-regulate the activation of ERK, thereby affecting the extracellular neutrophil trapping network (neutrophil extracellular The formation of traps,NETs and the release of neutrophil elastase (neutrophil elastase,NE). Ne-induced C _ 5 cleavage to C _ 5a played a pro-inflammatory effect, and there was no significant difference in liver injury and C5a expression between WT mice and SRA-- mice after the use of sivelestat sodium, an inhibitor of NE, in vivo. And we found that blocking SRA can alleviate liver injury induced by MHV-A59. SRA regulates neutrophil NET formation induced by MHV-A59 and promotes C5a production and subsequent liver injury. Inhibition of SRA may provide a new strategy for immunotherapy of FH.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R575.1
本文编号：2215845
[Abstract]:Fulminant hepatitis (Fulminant hepatitis,FH) is a rare acute disease characterized by rapid deterioration of liver function, massive necrosis of hepatocytes and even hepatic encephalopathy. Despite advances in treatment of FH in recent years, it can lead to higher mortality. Clinical evidence shows that fibrin deposition and microvascular thrombosis are important causes of hepatocyte injury in human FH process. In addition, the activation of immune cells and the subsequent production of pro-inflammatory cytokines (such as TNF- 伪, IL-1 尾, IL-6 and IFN- 纬) also play an important role in promoting the progression of FH. Therefore, the study of immunological pathogenesis of FH will provide ideas for the study of more general and effective treatment of FH. Scavenger receptor A (ScavengerReceptor Agna was mainly expressed on the surface of myeloid cells, such as macrophages and dendritic cells. Ozment found that SRA could also be expressed on the surface of neutrophils in circulation and bone marrow. After stimulation with TLR2 agonists, the expression of. SRA was up-regulated as a pattern recognition receptor (pattern recognition receptor,PRR) in innate immunity, which could recognize a wide range of "self" and "non-hexane" ligands. It plays an important role in resisting the invasion of pathogenic microorganisms and maintaining immune homeostasis. More and more studies have shown that SRA can also participate in the pathogenesis of various inflammatory diseases as an immunomodulator, and its immune regulation may be independent of its endocytosis. We found high expression of SRA in liver tissues of HBV infected fulminant hepatitis patients. However, the immunomodulatory effect of SRA in fulminant hepatitis has not been studied. Murine hepatitis virus (Mouse hepatitis virus,MHV) is a single positive strand RNA virus. It can be used to construct hepatitis, enteritis or encephalitis model. Balb / c and C57/BL6 mice are infected with hepatophilic MHV virus (such as MHV-3 and MHV-A59). Therefore, it can be used as an effective model for the study of human FH. Compared with the wild-type (wild-type,WT) mice, SRA-r- mice were resistant to fulminant hepatitis induced by MHV-A59, accompanied by the reduction of inflammatory reaction in the liver and the decrease of fibrinogen-like protein _ 2 Fgl2 in serum, and the liver injury was significantly alleviated by the use of C5aR antagonist. Moreover, the difference between WT mice and SRA-/- mice in liver inflammation and liver injury disappeared, which indicated that SRA increased the inflammatory effect and liver injury of MHV by up-regulating C5a expression during the FH process. The study found that, The difference of SRA expression of neutrophils in regulating liver injury induced by virus infection in WT mice and SRA-/- mice. SRA promotes MHV-A59 stimulation of TAK1 phosphorylation in neutrophilic granulocytes to up-regulate the activation of ERK, thereby affecting the extracellular neutrophil trapping network (neutrophil extracellular The formation of traps,NETs and the release of neutrophil elastase (neutrophil elastase,NE). Ne-induced C _ 5 cleavage to C _ 5a played a pro-inflammatory effect, and there was no significant difference in liver injury and C5a expression between WT mice and SRA-- mice after the use of sivelestat sodium, an inhibitor of NE, in vivo. And we found that blocking SRA can alleviate liver injury induced by MHV-A59. SRA regulates neutrophil NET formation induced by MHV-A59 and promotes C5a production and subsequent liver injury. Inhibition of SRA may provide a new strategy for immunotherapy of FH.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R575.1
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2 ;Detection of serum TNF-α,IFN-γ,IL-6 and IL-8 in patients with hepatitis B[J];世界胃肠病学杂志;1999年01期
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