Thioacetamide-induced norepinephrine production by hepatocytes is associated with hepatic stellate cell activation and liver fibrosis

2021 ◽  
Vol 14 ◽  
Author(s):  
Wei-Chien Tang ◽  
Ya-Wen Tang ◽  
Mingtian Che ◽  
Mei-Hui Wang ◽  
Keith K. Lai ◽  
...  

Background: Collagen production by activated hepatic stellate cells (HSCs) to encapsulate injury is part of the natural wound-healing response in injured liver. However, persistent activation of HSCs can lead to pathological fibrogenesis. Such persistent HSC activation could be mediated by norepinephrine (NE), a reaction product of dopamine beta-hydroxylase (DBH). Objective: To investigate the potential paracrine role of NE in hepatotoxin thioacetamide (TAA)-induced liver fibrosis. Methods/Results: In TAA-treated mice, fibrotic liver tissue showed significant increases in the mRNA expression of DBH up to 14-fold and collagen up to 7-fold. Immunohistochemical staining showed increased DBH protein expression in fibrotic liver tissue. Parenchymal hepatocyte cell line HepG2 expressed DBH and secreted NE, and the conditioned medium of HepG2 cells promoted collagenesis in nonparenchymal HSC cell line LX-2. TAA treatment increased DBH expression by 170% in HepG2 cells, as well as increased NE by 120% in the conditioned medium of HepG2 cells. The conditioned medium of TAA-treated HepG2 cells was used to culture LX-2 cells, and was found to increase collagen expression by 80% in LX-2 cells. Collagen expression was reduced by pre-treating HepG2 cells with siRNA targeting DBH or by adding NE antagonists to the conditioned medium. Finally, TAA-induced oxidative stress in HepG2 cells was associated with induction of DBH expression. Conclusion: Collectively, our results suggest a potential role for DBH/NE-mediated crosstalk between hepatocytes and HSCs in fibrogenesis. From a therapeutic standpoint, antagonism of DBH/NE induction in hepatocytes might be a useful strategy to suppress pathological fibrogenesis.

2021 ◽  
Vol 21 ◽  
Author(s):  
Fahim Rejanur Tasin ◽  
Debasish Halder ◽  
Chanchal Mandal

: Liver fibrosis is one of the leading causes for cirrhotic liver disease and the lack of therapies to treat fibrotic liver is a major concern. Liver fibrosis is mainly occurred by activation of hepatic stellate cells and some stem cell therapies had previously reported for treatment. However, due to some problems with cell-based treatment, a safe therapeutic agent is vehemently sought by the researchers. Extracellular vesicles are cell-derived nanoparticles that are employed in several therapeutic approaches, including fibrosis, for their ability to transfer specific molecules in the target cells. In this review the possibilities of extracellular vesicles to inactivate stellate cells are summarized and discussed. According to several studies, extracellular vesicles from different sources can either put beneficial or detrimental effects by regulating the activation of stellate cells. Therefore, targeting extracellular vesicles for maximizing or inhibiting their production is a potential approach for fibrotic liver treatment. Extracellular vesicles from different cells can also inactivate stellate cells by carrying out the paracrine effects of those cells, working as the agents. They are also implicated as smart carrier of anti-fibrotic molecules when their respective parent cells are engineered to produce specific stellate cell-regulating substances. A number of studies showed stellate cell activation can be regulated by up/downregulation of specific proteins, and extracellular vesicle-based therapies can be an effective move to exploit these mechanisms. In conclusion, EVs are advantageous nano-carriers with the potential to treat fibrotic liver by inactivating activated stellate cells by various mechanisms.


2021 ◽  
Author(s):  
Peng Qi ◽  
Ming-Ze Ma ◽  
Jing-Hua Kuai

Abstract Aim:To elucidate the inhibitory role of growth differentiation factor 15 (GDF15) in liver fibrosis and its possible activation mechanism in hepatic stellate cells of mice.Methods:We generated a GDF15-neutralizing antibody that can inhibit TGF-β1-induced activation of the TGF-β/Smad2/3 pathway in LX-2 cells. All the mice in this study were induced by carbon tetrachloride and thioacetamide. In addition, primary hepatic stellate cells from mice were isolated from fresh livers using Nycodenz density gradient separation. The severity and extent of liver fibrosis in mice were evaluated by Sirius Red and Masson staining. The effect of GDF15 on the activation of the TGF-β pathway was detected using dual-luciferase reporter assays and Western blotting assays.Results:The expression of GDF15 in cirrhotic liver tissue was higher than that in normal liver tissue. Blocking GDF15 with a neutralizing antibody resulted in a delay in primary hepatic stellate cell activation and remission of liver fibrosis induced by carbon tetrachloride or thioacetamide. Meanwhile, TGF-β pathway activation was partly inhibited by a GDF15-neutralizing antibody in primary hepatic stellate cells. These results indicated that GDF15 plays an important role in regulating HSC activation and liver fibrosis progression.Conclusions:The inhibition of GDF15 attenuates chemical-inducible liver fibrosis and delays hepatic stellate cell activation, and this effect is probably mainly attributed to its regulatory role in TGF-β signalling.


2020 ◽  
Vol 40 (03) ◽  
pp. 307-320
Author(s):  
Michitaka Matsuda ◽  
Ekihiro Seki

AbstractChronic liver injury due to viral hepatitis, alcohol abuse, and metabolic disorders is a worldwide health concern. Insufficient treatment of chronic liver injury leads to fibrosis, causing liver dysfunction and carcinogenesis. Most cases of hepatocellular carcinoma (HCC) develop in the fibrotic liver. Pathological features of liver fibrosis include extracellular matrix (ECM) accumulation, mesenchymal cell activation, immune deregulation, and angiogenesis, all of which contribute to the precancerous environment, supporting tumor development. Among liver cells, hepatic stellate cells (HSCs) and macrophages play critical roles in fibrosis and HCC. These two cell types interplay and remodel the ECM and immune microenvironment in the fibrotic liver. Once HCC develops, HCC-derived factors influence HSCs and macrophages to switch to protumorigenic cell populations, cancer-associated fibroblasts and tumor-associated macrophages, respectively. This review aims to summarize currently available data on the roles of HSCs and macrophages in liver fibrosis and HCC, with a focus on their interaction.


2015 ◽  
Vol 35 (3) ◽  
pp. 885-898 ◽  
Author(s):  
Xudong Zhang ◽  
Zhongming Tan ◽  
Youjing Wang ◽  
Junwei Tang ◽  
Runjiu Jiang ◽  
...  

Background/Aims: PTPRO (protein tyrosine phosphatase, receptor type O) is implicated in diverse physiological and pathological processes in cancer and hepatic ischemia/reperfusion injury, although little is known about its role in hepatic fibrosis. Methods: Here, by using genetically deficient mice, we reported that PTPRO knockout (PTPRO-/-) significantly attenuated liver injury, release of inflammatory factors, tissue remodeling, and liver fibrosis in two experimental mouse models of fibrogenesis induced by bile-duct ligation or carbon tetrachloride administration. Results: However, we proved that PTPRO expression was strongly downregulated in clinical and experimental liver fibrosis specimens. Further investigations revealed that stimulation of primary hepatic stellate cells (HSCs) and hepatocytes with specific activator platelet-derived growth factor (PDGF)-BB increased PTPRO transcription in HSCs but had the opposite effect in primary hepatocytes. More importantly, synthetic short hairpin RNA targeting PTPRO significantly neutralized PDGF-BB-induced HSC proliferation and myofibroblast marker expression through downregulated phosphorylation of extracellular signal-regulated kinase (ERK) and AKT. Conclusion: These observations confirm that PTPRO plays a critical role in liver fibrogenesis by affecting PDGF signaling in HSC activation and might be developed into a feasible therapeutic approach for the treatment of chronic fibrotic liver diseases.


2021 ◽  
Author(s):  
Ning Wang ◽  
Xiajing Li ◽  
Zhiyong Zhong ◽  
Yaqi Qiu ◽  
Shoupei Liu ◽  
...  

Abstract BackgroundExosomes secreted from stem cells exerted salutary effects on the fibrotic liver. Herein, the roles of exosomes derived from human embryonic stem cell (hESC) in anti-fibrosis were extensively investigated. Compared with two-dimensional (2D) culture, the clinical and biological relevance of three-dimensional (3D) cell spheroids were greater because of their higher regeneration potential since they behave more like cells in vivo. In our study, exosomes derived from 3D human embryonic stem cells (hESC) spheroids and the monolayer (2D) hESCs were collected and compared the therapeutic potential for fibrotic liver in vitro and in vivo. ResultsIn vitro, PKH26 labled-hESC-Exosomes were shown to be internalized and integrated into TGFβ-activated-LX2 cells, and reduced the expression of profibrogenic markers, thereby regulating cellular phenotypes. TPEF imaging indicated that PKH26-labled-3D-hESC-Exsomes possessed an enhanced capacity to accumulate in the livers and exhibited more dramatic therapeutic potential in the injured livers of fibrosis mouse model. 3D-hESC-Exosomes decreased profibrogenic markers and liver injury markers, and improved the level of liver functioning proteins, eventually restoring liver function of fibrosis mice. miRNA array revealed a significant enrichment of miR-6766-3p in 3D-hESC-Exosomes, moreover, bioinformatics and dual luciferase reporter assay identified and confirmed the TGFβRII gene as the target of miR-6766-3p. Furthermore, the delivery of miR-6766-3p into activated-LX2 cells decreased cell proliferation, chemotaxis and profibrotic effects, and further investigation demonstrated that the expression of target gene TGFβRII and its downstream SMADs proteins, especially phosphorylated protein p-SMAD2/3 was also notably down-regulated by miR-6766-3p. These findings unveiled that miR-6766-3p in 3D-hESC-Exosomes inactivated SMADs signaling by inhibiting TGFβRII expression, consequently attenuating stellate cell activation and suppressing liver fibrosis. ConclusionsOur results showed that miR-6766-3p in the 3D-hESC-Exosomes inactivates smads signaling by restraining TGFβRII expression, attenuated LX2 cell activation and suppressed liver fibrosis, suggesting that 3D-hESC-Exosome enriched-miR6766-3p is a novel anti-fibrotic therapeutics for treating chronic liver disease. These results also proposed a significant strategy that 3D-Exo could be used as natural nanoparticles to rescue liver injury via delivering antifibrotic miR-6766-3p.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Vaishaali Natarajan ◽  
Edward N. Harris ◽  
Srivatsan Kidambi

Liver fibrosis is a wound-healing response to chronic liver injury such as alcoholic/nonalcoholic fatty liver disease and viral hepatitis with no FDA-approved treatments. Liver fibrosis results in a continual accumulation of extracellular matrix (ECM) proteins and paves the way for replacement of parenchyma with nonfunctional scar tissue. The fibrotic condition results in drastic changes in the local mechanical, chemical, and biological microenvironment of the tissue. Liver parenchyma is supported by an efficient network of vasculature lined by liver sinusoidal endothelial cells (LSECs). These nonparenchymal cells are highly specialized resident endothelial cell type with characteristic morphological and functional features. Alterations in LSECs phenotype including lack of LSEC fenestration, capillarization, and formation of an organized basement membrane have been shown to precede fibrosis and promote hepatic stellate cell activation. Here, we review the interplay of LSECs with the dynamic changes in the fibrotic liver microenvironment such as matrix rigidity, altered ECM protein profile, and cell-cell interactions to provide insight into the pivotal changes in LSEC physiology and the extent to which it mediates the progression of liver fibrosis. Establishing the molecular aspects of LSECs in the light of fibrotic microenvironment is valuable towards development of novel therapeutic and diagnostic targets of liver fibrosis.


Author(s):  
Yiming Zhu ◽  
Chihao Zhang ◽  
Mingzhe Huang ◽  
Jiayun Lin ◽  
Xiao Fan ◽  
...  

Hepatic stellate cells (HSCs) are activated by inflammatory mediators to secrete extracellular matrix for collagen deposition, leading to liver fibrosis. Ferroptosis is iron- and lipid hydroperoxide-dependent programmed cell death, which has recently been targeted for inhibiting liver fibrogenic processes. Tripartite motif-containing protein 26 (TRIM26) is an E3 ubiquitin ligase that functions as a tumor suppressor in hepatocellular carcinoma, while little is known about its function in liver fibrosis. In the present study, the differential expression of TRIM26 in normal and fibrotic liver tissues was examined based on both online databases and specimens collected from patient cohort. The effects of TRIM26 on HSCs ferroptosis were examined in vitro through evaluating cell proliferation, lipid peroxidation, and expression of key ferroptosis-related factors. In vivo function of TRIM26 in liver fibrosis was examined based on CCl4-induced mice model. We found that TRIM26 was downregulated in fibrotic liver tissues. The overexpression of TRIM26 inhibited HSCs proliferation, promoted lipid peroxidation, manipulated ferroptosis-related factor expressions, and counteracted the effect of iron inhibitor deferoxamine. Moreover, TRIM26 physically interacted with solute carrier family-7 member-11 (SLC7A11), a critical protein for lipid reactive oxygen species (ROS) scavenging, and mediated its ubiquitination. In addition, TRIM26 overexpression induced HSCs ferroptosis and mitigated CCl4-induced liver fibrosis in mice. In conclusion, TRIM26 promotes HSCs ferroptosis to suppress liver fibrosis through mediating the ubiquitination of SLC7A11. The TRIM26-targeted SLC7A11 suppression can be a novel therapeutic strategy for liver fibrosis.


2020 ◽  
Vol 10 (17) ◽  
pp. 5941
Author(s):  
Yi-Jen Liao ◽  
Yuan-Hsi Wang ◽  
Chao-Lien Liu ◽  
Cheng-Chieh Fang ◽  
Ming-Hua Hsu ◽  
...  

Liver fibrosis initiates the progression of cirrhosis, and, finally, hepatocellular carcinoma (HCC). The increased proliferation and activation of hepatic stellate cells (HSCs) are crucial for hepatic fibrogenesis. Paeonol is the major vigorous component of Cortex Moutan, a traditional herbal medicine widely used for treating various diseases. Here, we identified a novel paeonol derivative (4-methoxy sulfonyl paeonol, 4-MSP) that inhibits TGF-β1-induced Smad2/3 phosphorylation and collagen expression in HSCs. 4-MSP pretreatment suppressed the PDGF-BB–induced phosphorylation of MAPK pathway members (MEK/ERK, p38, JNK), Akt/p70S6K, and HSC proliferation. However, 4-MSP treatment had no effect on the induction of apoptosis in HSCs. The microarray experiments showed that 4-MSP treatment affects the TGF-β signaling, MAPK cascade, and other pathways related to HSCs activation and proliferation. The administration of 4-MSP to a liver fibrosis mouse model induced by CCl4 significantly decreased the expression of hepatic fibrosis markers (α-SMA, col1A2, TGF-β, and MMP2), and attenuated hepatic collagen deposition and liver damage. In addition, no adverse effects were observed in 4-MSP exposed mice. In conclusion, this novel paeonol-phenylsulfonyl derivative prevents the progression of liver fibrosis through blocking TGF-β1/Smad, PDGF-BB/MAPK, and Akt signaling, which suggests its use as a novel therapeutic against liver fibrosis.


2020 ◽  
Vol 40 (3) ◽  
Author(s):  
Jianjian Zhao ◽  
Yueping Jiang ◽  
Xueguo Sun ◽  
Xishuang Liu ◽  
Fuguo Liu ◽  
...  

Abstract Background: The activation of hepatic stellate cells (HSCs) plays a central role in liver fibrosis. α-ketoglutarate is a natural metabolite and previous studies have shown that increase in intracellular α-ketoglutarate can inhibit HSC activation. Aim: The aim of the present study is to determine the changes and role of intracellular α-ketoglutarate in HSC activation and clarify its mechanism of action. Methods: A human HSC cell line (LX-2) and the primary mouse HSC were used in the present study. We detected the changes of intracellular α-ketoglutarate levels and the expression of enzymes involved in the metabolic processes during HSC activation. We used siRNA to determine the role of intracellular α-ketoglutarate in HSC activation and elucidate the mechanism of the metabolic changes. Results: Our results demonstrated that intracellular α-ketoglutarate levels decreased with an HSC cell line and primary mouse HSC activation, as well as the expression of isocitrate dehydrogenase 2 (IDH2), an enzyme that catalyzes the production of α-ketoglutarate. In addition, knockdown of IDH2 efficiently promoted the activation of HSCs, which was able to be reversed by introduction of an α-ketoglutarate analogue. Furthermore, we demonstrated that α-ketoglutarate regulated HSC activation is independent of transforming growth factor-β1 (TGF-β1). Conclusions: Our findings demonstrated that decrease in IDH2 expression limits the production of α-ketoglutarate during HSC activation and in turn promotes the activation of HSCs through a TGF-β1 independent pathway. The present study suggests that IDH2 and α-ketoglutarate may be potential new targets for the prevention and treatment of liver fibrosis.


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