scholarly journals Downregulation of RIP3 Improves the Protective Effect of ATF6 in an Acute Liver Injury Model

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Mei-Ying Huang ◽  
Dian-Wei Wan ◽  
Jie Deng ◽  
Wen-Jie Guo ◽  
Yue Huang ◽  
...  
Keyword(s):  
Liver Injury ◽  
Er Stress ◽  
Acute Liver Injury ◽  
Recovery Process ◽  
Regulatory Relationship ◽  
Negative Feedback Regulation ◽  
Injury Model ◽  
The Impact

Background. Activating transcription factor 6 (ATF6) and receptor-interacting protein 3 (RIP3) are important signaling proteins in endoplasmic reticulum (ER) stress and necroptosis, respectively. However, their regulatory relationship and clinical significance are unknown. We investigate the impact of ATF6 on RIP3 expression, and its role in hepatocyte necroptosis in an acute liver injury model. Methods. In vivo and in vitro experiments were carried out. LO2 cells were treated with thapsigargin (TG). In vivo, male BALB/c mice were treated with carbon tetrachloride (CCl4, 1 mL/kg) or tunicamycin (TM, 2 mg/kg). Then, the impact of ATF6 or RIP3 silencing on liver injury, hepatocyte necroptosis, and ER stress-related protein expression was examined. Results. TG induced ER stress and necroptosis and ATF6 and RIP3 expression in LO2 cells. The knockdown of ATF6 significantly decreased RIP3 expression ( p < 0.05 ) and increased ER stress and necroptosis. The downregulation of RIP3 significantly reduced necroptosis and ER stress ( p < 0.05 ). Similar results were observed in CCl4 or the TM-induced mouse model. The knockdown of ATF6 significantly decreased CCl4-induced RIP3 expression and increased liver injury, necroptosis, and ER stress in mice livers ( p < 0.05 ). In contrast, the downregulation of RIP3 significantly reduced liver injury, hepatocyte necroptosis, and ER stress. Conclusions. Hepatocyte ATF6 has multiple roles in acute liver injury. It reduces hepatocyte necroptosis via negative feedback regulation of ER stress. In addition, ATF6 can upregulate the expression of RIP3, which is not helpful to the recovery process. However, downregulating RIP3 reduces hepatocyte necroptosis by promoting the alleviation of ER stress. The findings suggest that RIP3 could be a plausible target for the treatment of liver injury.

Salvianolic acid B exerts a protective effect in acute liver injury by regulating the Nrf2/HO-1 signaling pathway

2020 ◽  
Vol 98 (3) ◽  
pp. 162-168 ◽  
Author(s):  
Yong-mei Jin ◽  
Xiang-ming Tao ◽  
Yi-ning Shi ◽  
Youjin Lu ◽  
Jin-yu Mei
Keyword(s):  
Liver Injury ◽  
Signaling Pathway ◽  
Acute Liver Injury ◽  
Damage Model ◽  
Underlying Mechanism ◽  
Salvianolic Acid B ◽  
Salvianolic Acid ◽  
Injury Model

Salvianolic acid B (Sal B) exerts strong antioxidant activity and eliminates the free radical effect. However, how it affects the antioxidant pathway is not very clear. The objective of this study was to investigate the underlying mechanism of Sal B in CCl4-induced acute liver injury, especially its effect on the Nrf2/HO-1 signaling pathway. For the in vivo experiment, an acute liver injury model was induced using CCl4 and treated with Sal B. For the in vitro experiment, an oxidative damage model was established followed by Sal B treatment. Serum biochemical indicators and reactive oxygen species activity were detected using corresponding kits. Oxidant/antioxidant status was determined based on the levels of malondialdehyde, glutathione, and superoxide dismutase. Nrf2 and HO-1 levels were analyzed by Western blotting and immunohistochemical staining. Sal B treatment improved liver histology, decreased the aminotransferase levels, and attenuated oxidative stress in the acute liver injury model. Nrf2 and HO-1 levels were increased both in vivo and in vitro. Sal B suppresses acute liver injury and Nrf2/HO-1 signaling plays a key role in this process.

scholarly journals 5-O-Demethylnobiletin Alleviates CCl4-Induced Acute Liver Injury by Equilibrating ROS-Mediated Apoptosis and Autophagy Induction

2021 ◽  
Vol 22 (3) ◽  
pp. 1083
Author(s):  
Sukkum Ngullie Chang ◽  
Se Ho Kim ◽  
Debasish Kumar Dey ◽  
Seon Min Park ◽  
Omaima Nasif ◽  
...  
Keyword(s):  
Liver Injury ◽  
Acute Liver Injury ◽  
Elevated Serum ◽  
In Vitro Study ◽  
Biological Properties ◽  
Autophagic Flux ◽  
Serum Aminotransferase ◽  
Ccl4 Treatment

Polymethoxyflavanoids (PMFs) have exhibited a vast array of therapeutic biological properties. 5-O-Demethylnobiletin (5-DN) is one such PMF having anti-inflammatory activity, yet its role in hepatoprotection has not been studied before. Results from in vitro study revealed that 5-DN did not exert a high level of cytotoxicity on HepG2 cells at 40 μM, and it was able to rescue HepG2 cell death induced by carbon tetrachloride (CCl4). Subsequently, we investigated acute liver injury on BALB/c mice induced by CCl4 through the intraperitoneal injection of 1 mL/kg CCl4 and co-administration of 5-DN at (1 and 2 mg/kg) by oral gavage for 15 days. The results illustrated that treatment with 5-DN attenuated CCl4-induced elevated serum aminotransferase (AST)/alanine aminotransferase (ALT) ratio and significantly ameliorated severe hepatic damage such as inflammation and fibrosis evidenced through lesser aberrations in the liver histology of 5-DN dose groups. Additionally, 5-DN efficiently counteracted and equilibrated the production of ROS accelerated by CCl4 and dramatically downregulated the expression of CYP2E1 vitally involved in converting CCl4 to toxic free radicals and also enhanced the antioxidant enzymes. 5-DN treatment also inhibited cell proliferation and inflammatory pathway abnormally regulated by CCl4 treatment. Furthermore, the apoptotic response induced by CCl4 treatment was remarkably reduced by enhanced Bcl-2 expression and noticeable reduction in Bax, Bid, cleaved caspase 3, caspase 9, and apaf-1 expression. 5-DN treatment also induced the conversion of LC3 and promoted the autophagic flux. Conclusively, 5-DN exhibited hepatoprotective effects in vitro and in vivo and prevented liver fibrosis induced by CCl4.

scholarly journals Mechanism of KLF4 Protection against Acute Liver Injury via Inhibition of Apelin Signaling

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Weitao Ji ◽  
Hongyun Shi ◽  
Hailin Shen ◽  
Jing Kong ◽  
Jiayi Song ◽  
...  
Keyword(s):  
Liver Injury ◽  
Signaling Pathway ◽  
Acute Liver Injury ◽  
Control Group ◽  
Necrosis Factor Alpha ◽  
Protein Levels ◽  
Klf4 Expression ◽  
Mrna And Protein Expression

Krüppel-like factor 4 (KLF4) is a key transcription factor that regulates genes involved in the proliferation or differentiation in different tissues. Apelin plays roles in cardiovascular functions, metabolic disease, and homeostatic disorder. However, the biological function of apelin in liver disease is still ongoing. In this study, we investigated the mechanism of KLF4-mediated protection against acute liver injury via the inhibition of the apelin signaling pathway. Mice were intraperitoneally injected with carbon tetrachloride (CCl4; 0.2 mL dissolved in 100 mL olive oil, 10 mL/kg) to establish an acute liver injury model. A KLF4 expression plasmid was injected through the tail vein 48 h before CCl4 treatment. In cultured LX-2 cells, pAd-KLF4 or siRNA KLF4 was overexpressed or knockdown, and the mRNA and protein levels of apelin were determined. The results showed that the apelin serum level in the CCl4-injected group was higher than that of control group, and the expression of apelin in the liver tissues was elevated while KLF4 expression was decreased in the CCl4-injected group compared to the KLF4-plasmid-injected group. HE staining revealed serious hepatocellular steatosis in the CCl4-injected mice, and KLF4 alleviated this steatosis in the mice injected with KLF4 plasmid. In vitro experiments showed that tumor necrosis factor-alpha (TNF-α) could downregulate the transcription and translation levels of apelin in LX-2 cells and also upregulate KLF4 mRNA and protein expression. RT-PCR and Western blotting showed that the overexpression of KLF4 markedly decreased basal apelin expression, but knockdown of KLF4 restored apelin expression in TNF-α-treated LX-2 cells. These in vivo and in vitro experiments suggest that KLF4 plays a key role in inhibiting hepatocellular steatosis in acute liver injury, and that its mechanism might be the inhibition of the apelin signaling pathway.

scholarly journals Protective Effect of Eckol against Acute Hepatic Injury Induced by Carbon Tetrachloride in Mice

Marine Drugs ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. 300 ◽  
Author(s):  
Shulan Li ◽  
Juan Liu ◽  
Mengya Zhang ◽  
Yuan Chen ◽  
Tianxing Zhu ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Liver Injury ◽  
Protective Effect ◽  
Acute Liver Injury ◽  
Treated Group ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Enhanced Expression ◽  
Pre Treatment

Several in vitro studies have shown the potential hepatoprotective properties of eckol, a natural phlorotannin derived from the brown alga. However, the in vivo hepatoprotective potential of eckol has not been determined. In this study, we performed an in vivo study to investigate the protective effect of eckol and its possible mechanisms on the carbon tetrachloride (CCl4)-induced acute liver injury model in mice. Results revealed that eckol pre-treatment at the dose of 0.5 and 1.0 mg/kg/day for 7 days significantly suppressed the CCl4-induced increases of alanine transaminase (ALT) and aspartate aminotransferase (AST) levels in serum and meliorated morphological liver injury. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) analysis showed that the number of positive apoptotic hepatocytes in the eckol-treated group was lower than that in the CCl4 model group. Western blotting analysis also demonstrated the enhanced expression of bcl-2 and suppressed expression of cleaved caspase-3 by eckol. The CCl4-induced oxidative stress in liver was significantly ameliorated by eckol, which was characterized by reduced malondialdehyde (MDA) formations, and enhanced superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and glutathione (GSH) content. Moreover, the CCl4-induced elevations of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were markedly suppressed in the eckol-treated group. However, eckol enhanced the level of IL-10, a potent anti-inflammatory cytokine, and recruited CD11c+ dendritic cells into the liver tissues of CCl4-treated mice. These results indicated that eckol has the protective effect on CCl4-induced acute liver injury via multiple mechanisms including anti-apoptosis, anti-oxidation, anti-inflammation and immune regulation.

scholarly journals Comparative Proteomic Identification of Protein Disulphide Isomerase A6 Associated with Tert-Butylhydroperoxide-Induced Liver Injury in Rat Hepatocytes

2018 ◽  
Vol 45 (5) ◽  
pp. 1915-1926 ◽  
Author(s):  
Chien-Heng Shen ◽  
Shui-Yi Tung ◽  
Wen-Shih Huang ◽  
Kam-Fai Lee ◽  
Yung-Yu Hsieh ◽  
...  
Keyword(s):  
Liver Injury ◽  
Cell Viability ◽  
Er Stress ◽  
Primary Cultures ◽  
Liver Cells ◽  
Cytochrome C Release ◽  
Dapi Staining ◽  
Tert Butylhydroperoxide

Background/Aims: Oxidants are important human toxicants. They have been implicated in the occurrence and development of liver diseases. Increased intracellular tert-butylhydroperoxide (t-BHP) may be critical for oxidant toxicity, and is commonly used for evaluating mechanisms involving oxidative stress, but the method remains controversial. Methods: Primary cultures of hepatocytes as well as human Hep G2 and mouse FL83B liver cells were obtained. Cell viability was measured by annexin V–FITC/propidium iodide and DAPI staining to determine the effects of t-BHP treatment on acute liver injury. A proteomic assay provided information that was used to identify the differentially expressed proteins following t-BHP treatment; immunohistochemistry and western blotting were performed to detect the expression of PDIA6 activity in apoptotic and endoplasmic reticulum (ER) stress pathways. Results: Our results demonstrate that t-BHP treatment of liver cells increased cell cytotoxicity and the generation of reactive oxygen species. This treatment also increased the level of PDIA6; this was validated in vitro and in vivo based on a comparison of t-BHP-treated and -untreated groups. Treatment of mouse liver FL83B cells with t-BHP activated caspase 3, increased the expression of apoptotic molecules, caused cytochrome c release, and induced Bcl-2, Bax and IRE1α/TRAF2 complex formation. t-BHP-dependent induction of apoptosis was accompanied by sustained phosphorylation of the IRE1α/ASK1/JNK1/2/p38 pathways and PDIA6 expression. Furthermore, t-BHP induced liver FL83B cell viability and apoptosis by upregulating the levels of PDIA6; this process could be involved in the activation of the IRE1α/ASK1/JNK1/2/p38 signalling pathways. Conclusions: We conclude that t-BHP induced an apoptosis cascade and ER stress in hepatocytes by upregulation of PDIA6, providing a new mechanism underlying the effects of t-BHP on liver injury.

Dendrobium officinale polysaccharides protected against ethanol-induced acute liver injury in vivo and in vitro via the TLR4/NF-κB signaling pathway

Cytokine ◽  
2020 ◽  
Vol 130 ◽  
pp. 155058 ◽  
Author(s):  
Ke Yang ◽  
Lianghui Zhan ◽  
Tingting Lu ◽  
Cong Zhou ◽  
Xue Chen ◽  
...  
Keyword(s):  
Liver Injury ◽  
Signaling Pathway ◽  
Acute Liver Injury ◽  
Dendrobium Officinale

scholarly journals Graptopetalum paraguayense Inhibits Liver Fibrosis by Blocking TGF-β Signaling In Vivo and In Vitro

2019 ◽  
Vol 20 (10) ◽  
pp. 2592 ◽  
Author(s):  
Wei-Hsiang Hsu ◽  
Se-Chun Liao ◽  
Yau-Jan Chyan ◽  
Kai-Wen Huang ◽  
Shih-Lan Hsu ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Rat Liver ◽  
Injury Model ◽  
Ethanol Extracts ◽  
And Migration ◽  
Tgf Β1

Background and Aims: Liver fibrosis is the excessive accumulation of extracellular matrix proteins, including collagen, which occurs in most types of chronic liver diseases. Advanced liver fibrosis results in cirrhosis, liver failure, and portal hypertension. Activated hepatic perivascular stellate cells, portal fibroblasts, and myofibroblasts of bone marrow origin have been identified as major collagen-producing cells in the injured liver. These cells are activated by fibrogenic cytokines, such as TGF-β1. The inhibition of TGF-β1 function or synthesis is a major target for the development of antifibrotic therapies. Our previous study showed that the water and ethanol extracts of Graptopetalum paraguayense (GP), a Chinese herbal medicine, can prevent dimethylnitrosamine (DMN)-induced hepatic inflammation and fibrosis in rats. Methods: We used rat hepatic stellate HSC-T6 cells and a diethylnitrosamine (DEN)-induced rat liver injury model to test the potential mechanism of GP extracts and its fraction, HH-F3. Results: We demonstrated that GP extracts and HH-F3 downregulated the expression levels of extracellular matrix (ECM) proteins and inhibited the proliferation and migration via suppression of the TGF-β1 pathway in rat hepatic stellate HSC-T6 cells. Moreover, the HH-F3 fraction decreased hepatic collagen content and reduced plasma AST, ALT, and γ-GT activities in a DEN-induced rat liver injury model, suggesting that GP/HH-F3 has hepatoprotective effects against DEN-induced liver fibrosis. Conclusion: These findings indicate that GP/HH-F3 may be a potential therapeutic agent for the treatment of liver fibrosis. The inhibition of TGF-β-mediated fibrogenesis may be a central mechanism by which GP/HH-F3 protects the liver from injury.

Endoplasmic Reticulum Stress Increases Multidrug-resistance Protein 2 Expression and Mitigates Acute Liver Injury

2020 ◽  
Vol 20 (7) ◽  
pp. 548-557
Author(s):  
Wen-Ge Huang ◽  
Jun Wang ◽  
Yu-Juan Liu ◽  
Hong-Xia Wang ◽  
Si-Zhen Zhou ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Multidrug Resistance ◽  
Liver Injury ◽  
Protein Expression ◽  
Er Stress ◽  
Acute Liver Injury ◽  
Multidrug Resistance Protein ◽  
Functional Involvement ◽  
Resistance Protein ◽  
The Impact

Background: Multidrug-resistance protein (MRP) 2 is a key membrane transporter that is expressed on hepatocytes and regulated by nuclear factor kappa B (NF-κB). Interestingly, endoplasmic reticulum (ER) stress is closely associated with liver injury and the activation of NF-κB signaling. Objective: Here, we investigated the impact of ER stress on MRP2 expression and the functional involvement of MRP2 in acute liver injury. Methods: ER stress, MRP2 expression, and hepatocyte injury were analyzed in a carbon tetrachloride (CCl4)-induced mouse model of acute liver injury and in a thapsigargin (TG)-induced model of ER stress. Results: CCl4 and TG induced significant ER stress, MRP2 protein expression and NF- κB activation in mice and LO2 cells (P < 0.05). Pretreatment with ER stress inhibitor 4- phenyl butyric acid (PBA) significantly mitigated CCl4 and TG-induced ER stress and MRP2 protein expression (P < 0.05). Moreover, pretreatment with pyrrolidine dithiocarbamic acid (PDTC; NF-κB inhibitor) significantly inhibited CCl4-induced NF-κB activation and reduced MRP2 protein expression (1±0.097 vs. 0.623±0.054; P < 0.05). Furthermore, hepatic downregulation of MRP2 expression significantly increased CCl4- induced ER stress, apoptosis, and liver injury. Conclusion: ER stress enhances intrahepatic MRP2 protein expression by activating NF-κB. This increase in MRP2 expression mitigates ER stress and acute liver injury.

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