Clara Cell 10 kDa Protein Alleviates Murine Hepatitis Virus Strain 3-Induced Fulminant Hepatitis by Inhibiting Fibrinogen-Like Protein 2 Expression
Clara Cell 10 kDa Protein Alleviates Murine Hepatitis Virus Strain 3-Induced Fulminant Hepatitis by Inhibiting Fibrinogen-Like Protein 2 Expression
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DOI：
10.3389/fimmu.2018.02935
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发表时间：
2018-12
影响因子：
7.3
通讯作者：
Hai-jing Yu;Yang Liu;Hongwu Wang;Xiaoyang Wan;Jiaquan Huang;Weiming Yan;D. Xi;Xiaoping Luo
中科院分区：
文献类型：
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作者：
Hai-jing Yu;Yang Liu;Hongwu Wang;Xiaoyang Wan;Jiaquan Huang;Weiming Yan;D. Xi;Xiaoping Luo
背景：暴发性肝炎（FH）是一种严重威胁人类生命的疾病，伴有大量快速的坏死性炎症。枯否细胞是参与先天免疫应答的主要免疫细胞群，被认为是FH的核心。纤维蛋白原样蛋白2（Fgl 2）是在病毒感染时在巨噬细胞中基本上被诱导的促凝血蛋白，并且Fgl 2耗竭抑制鼠肝炎病毒株3（MHV-3）感染。Clara细胞10 kDa（CC 10）蛋白是一种分泌性蛋白，在变应性鼻炎和哮喘中具有抗炎特性。但其作用机制及在其他疾病中的致病作用尚不清楚。在这项研究中，我们旨在确定CC 10在FH中的作用以及CC 10对Fgl 2的调节。方法：腹腔注射MHV-3建立小鼠FH模型。在病毒感染前，小鼠通过尾静脉注射CC 10蛋白。检测存活率、肝功能、肝组织学、纤维蛋白沉积和坏死。用THP-1细胞和小鼠腹腔巨噬细胞体外研究CC 10对Fgl 2表达的调节作用。结果如下：在MHV-3诱导的小鼠FH模型中，与仅生理盐水对照组相比，CC 10组的存活率从0增加至12.5%。同时，能显著降低血清ALT、AST水平，减轻肝损害。此外，CC 10蛋白可明显下调肝Fgl 2、TNF-α和IL-1β的表达，并伴有纤维蛋白沉积，减少肝细胞凋亡。体外实验中，CC 10可显著抑制IFN-γ处理的THP-1细胞和MHV-3感染的小鼠腹腔巨噬细胞中Fgl 2的表达。然而，如免疫共沉淀所示，CC 10和Fgl 2之间没有直接相互作用。基因芯片研究表明，HMG盒转录因子1（HBP 1）在CC 10处理和IFN-γ致敏的THP-1细胞中显著降低。HBP 1-siRNA处理消除了CC 10对人脐静脉内皮细胞（HUVECs）中Fgl 2表达的抑制作用。结论：CC 10通过抑制巨噬细胞Fgl 2的表达而对MHV-3诱导的FH具有保护作用。这种作用可能是由转录因子HBP 1介导的。
Background: Fulminant hepatitis (FH) is a serious threat to human life, accompanied by massive and rapid necroinflammation. Kupffer cells, the major immune cell population involved in innate immune responses, are considered to be central for FH. Fibrinogen-like protein 2 (Fgl2) is a pro-coagulant protein that is substantially induced in macrophages upon viral infection, and Fgl2 depletion represses murine hepatitis virus strain 3 (MHV-3) infection. Clara cell 10 kDa (CC10) protein is a secretory protein with anti-inflammatory properties in allergic rhinitis and asthma. However, its mechanisms of action and pathogenic roles in other disease are still unclear. In this study, we aimed to determine the role of CC10 in FH and the regulation of Fgl2 by CC10. Methods: A mouse FH model was established by peritoneal injection of MHV-3. The mice received CC10 protein through tail vein injection before viral infection. Survival rate, liver function, liver histology, fibrin deposition, and necrosis were examined. The regulatory effect of CC10 on Fgl2 expression was investigated using THP-1 cells and mouse peritoneal macrophages in vitro. Results: In the mouse FH model induced by MHV-3, the survival rate increased from 0 to 12.5% in the CC10 group compared to that in the saline-only control group. Meanwhile, the levels of ALT and AST in serum were significantly decreased and liver damage was reduced. Furthermore, hepatic Fgl2, TNF-α, and IL-1β expression was obviously downregulated together with fibrin deposition, and hepatocyte apoptosis was reduced after administration of CC10 protein. In vitro, CC10 was found to significantly inhibit the expression of Fgl2 in IFN-γ-treated THP-1 cells and MHV-3-infected mouse peritoneal macrophages by western blot and real-time PCR. However, there was no direct interaction between CC10 and Fgl2 as shown by co-immunoprecipitation. Microarray investigations suggested that HMG-box transcription factor 1 (HBP1) was significantly low in CC10-treated and IFN-γ-primed THP-1 cells. HBP1-siRNA treatment abrogated the inhibitory effect of CC10 on Fgl2 expression in Human Umbilical Vein Endothelial cells (HUVECs). Conclusion:CC10 protects against MHV-3-induced FH via suppression of Fgl2 expression in macrophages. Such effects may be mediated by the transcription factor HBP1.