载脂蛋白 A5 通过抑制 TLR4 介导的 NF-κB 通路缓解 LPS/D-GalN 诱导的小鼠暴发性肝衰竭。
Apolipoprotein A5 alleviates LPS/D-GalN-induced fulminant liver failure in mice by inhibiting TLR4-mediated NF-κB pathway.
机构信息
Center of Infectious Diseases, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Wuhou District, Chengdu, 610041, China.
Division of Infectious Diseases, National Key Laboratory of Biotherapy (Sichuan University), West China Hospital of Sichuan University, Chengdu, 610041, China.
出版信息
J Transl Med. 2019 May 10;17(1):151. doi: 10.1186/s12967-019-1900-9.
BACKGROUND
Fulminant liver failure (FHF) is a serious clinical problem and liver transplantation is the major intervention. But the overall survival rate of FHF is low owing to the donated organ shortage. Apolipoprotein A-V (ApoA5) is a regulator of triglyceride metabolism and has been reported to act as a predictor for remnant liver growth after preoperative portal vein embolization and liver surgery. This study aimed to investigate the therapeutic effect of ApoA5 on lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced fulminant liver failure in mice.
METHODS
FHF mouse model was established using LPS/D-GalN and ApoA5 plasmid was injected by tail vein prior to LPS/D-GalN treatment. The expressions of ApoA5, toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B p65 (NF-κBp65) were assessed by real-time PCR and western blotting. Serum alanine aminotransferase (ALT) and tumor necrosis factor-α (TNF-α) levels were measured using automatic biochemical analyzer. Histological assessment and immunohistochemical (IHC) staining were conducted. Survival rate after LPS/D-GalN administration was also determined with Kaplan-Meier curve. Meanwhile, the expression of ApoA5 in injured huh7 cells was tested. Cell apoptosis analysis was performed after huh7 cells were transfected with ApoA5 plasmid and stimulated with LPS.
RESULTS
The expressions of ApoA5 decreased both in injured huh7 cells and FHF mice. ApoA5 overexpression reduced cell death rate using flow cytometry. ApoA5 not only decreased the serum ALT and TNF-α levels but also attenuated hepatic damage in hematoxylin-eosin (HE)-stained liver section. The protein expressions of TLR4, MyD88 and NF-κBp65 were inhibited when ApoA5 overexpressed. But the inhibitory effect would weaken with the increasing concentration of LPS in spite of ApoA5 overexpression. Besides, ApoA5 improved liver injury in a dose-dependent manner and the survival rate in FHF mice increased with increasing concentration of ApoA5.
CONCLUSION
ApoA5 had a protective effect against LPS/D-GalN-induced fulminant liver failure in mice within a certain range by inhibiting TLR4-mediated NF-κB pathway.
背景
暴发性肝衰竭（FHF）是一种严重的临床问题，肝移植是主要干预措施。但是，由于供体器官短缺，FHF 的总体存活率仍然很低。载脂蛋白 A-V（ApoA5）是甘油三酯代谢的调节剂，并且据报道，它可以作为术前门静脉栓塞和肝手术后残余肝脏生长的预测因子。本研究旨在探讨 ApoA5 对脂多糖/半乳糖胺（LPS/D-GalN）诱导的小鼠暴发性肝衰竭的治疗作用。
方法
使用 LPS/D-GalN 建立 FHF 小鼠模型，并在 LPS/D-GalN 处理前通过尾静脉注射 ApoA5 质粒。通过实时 PCR 和 Western blot 检测 ApoA5、Toll 样受体 4（TLR4）、髓样分化因子 88（MyD88）和核因子 kappa B p65（NF-κBp65）的表达。使用自动生化分析仪测量血清丙氨酸氨基转移酶（ALT）和肿瘤坏死因子-α（TNF-α）水平。进行组织学评估和免疫组织化学（IHC）染色。还通过 Kaplan-Meier 曲线确定 LPS/D-GalN 给药后的存活率。同时，检测受损 huh7 细胞中的 ApoA5 表达。用 LPS 刺激转染 ApoA5 质粒后的 huh7 细胞后进行细胞凋亡分析。
结果
ApoA5 在受损的 huh7 细胞和 FHF 小鼠中均表达降低。ApoA5 过表达通过流式细胞术降低细胞死亡率。ApoA5 不仅降低了血清 ALT 和 TNF-α 水平，而且减轻了苏木精-伊红（HE）染色肝切片中的肝损伤。过表达 ApoA5 时，TLR4、MyD88 和 NF-κBp65 的蛋白表达受到抑制。但是，尽管过表达 ApoA5，随着 LPS 浓度的增加，抑制作用会减弱。此外，ApoA5 以剂量依赖性方式改善肝损伤，并且 FHF 小鼠的存活率随着 ApoA5 浓度的增加而增加。
结论
在一定范围内，ApoA5 通过抑制 TLR4 介导的 NF-κB 通路对 LPS/D-GalN 诱导的小鼠暴发性肝衰竭具有保护作用。
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