scholarly journals The Endothelium as a Driver of Liver Fibrosis and Regeneration

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 929 ◽  
Author(s):  
Erica Lafoz ◽  
Maria Ruart ◽  
Aina Anton ◽  
Anna Oncins ◽  
Virginia Hernández-Gea
Keyword(s):  
Endothelial Cells ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Stellate Cell ◽  
Public Health Problem ◽  
Cell Types ◽  
Regenerative Process ◽  
Research Field ◽  
Major Public Health Problem ◽  
Liver Sinusoidal Endothelial Cells

Liver fibrosis is a common feature of sustained liver injury and represents a major public health problem worldwide. Fibrosis is an active research field and discoveries in the last years have contributed to the development of new antifibrotic drugs, although none of them have been approved yet. Liver sinusoidal endothelial cells (LSEC) are highly specialized endothelial cells localized at the interface between the blood and other liver cell types. They lack a basement membrane and display open channels (fenestrae), making them exceptionally permeable. LSEC are the first cells affected by any kind of liver injury orchestrating the liver response to damage. LSEC govern the regenerative process initiation, but aberrant LSEC activation in chronic liver injury induces fibrosis. LSEC are also main players in fibrosis resolution. They maintain liver homeostasis and keep hepatic stellate cell and Kupffer cell quiescence. After sustained hepatic injury, they lose their phenotype and protective properties, promoting angiogenesis and vasoconstriction and contributing to inflammation and fibrosis. Therefore, improving LSEC phenotype is a promising strategy to prevent liver injury progression and complications. This review focuses on changes occurring in LSEC after liver injury and their consequences on fibrosis progression, liver regeneration, and resolution. Finally, a synopsis of the available strategies for LSEC-specific targeting is provided.

scholarly journals SECs (Sinusoidal Endothelial Cells), Liver Microenvironment, and Fibrosis

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Vaishaali Natarajan ◽  
Edward N. Harris ◽  
Srivatsan Kidambi
Keyword(s):  
Endothelial Cells ◽  
Liver Fibrosis ◽  
Cell Activation ◽  
Stellate Cell ◽  
Protein Profile ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells ◽  
Fibrotic Liver ◽  
Nonalcoholic Fatty Liver ◽  
Functional Features

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.

scholarly journals Angiocrine signaling in the hepatic sinusoids in health and disease

2016 ◽  
Vol 311 (2) ◽  
pp. G246-G251 ◽  
Author(s):  
Enis Kostallari ◽  
Vijay H. Shah
Keyword(s):  
Endothelial Cells ◽  
Cell Activation ◽  
Stellate Cell ◽  
Cell Types ◽  
Hepatocyte Proliferation ◽  
Liver Sinusoidal Endothelial Cells ◽  
Functional Changes ◽  
Liver Zonation ◽  
Health And Disease ◽  
Short Synthesis

The capillary network irrigating the liver is important not only for nutrient and oxygen delivery, but also for the signals distributed to other hepatic cell types necessary to maintain liver homeostasis. During development, endothelial cells are a key component in liver zonation. In adulthood, they maintain hepatic stellate cells and hepatocytes in quiescence. Their importance in pathobiology is highlighted in liver regeneration and chronic liver diseases, where they coordinate paracrine cell behavior. During regeneration, liver sinusoidal endothelial cells induce hepatocyte proliferation and angiogenesis. During fibrogenesis, they undergo morphological and functional changes, which are reflected by their role in hepatic stellate cell activation, inflammation, and distorted sinusoidal structure. Therapeutic strategies to target angiocrine signaling are in progress but are in the early stages. Here, we offer a short synthesis of recent studies on angiocrine signaling in liver homeostasis, regeneration, and fibrogenesis.

Targeting ER protein TXNDC5 in hepatic stellate cell mitigates liver fibrosis by repressing non-canonical TGFβ signalling

Gut ◽  
2021 ◽  
pp. gutjnl-2021-325065
Author(s):  
Chen-Ting Hung ◽  
Tung-Hung Su ◽  
Yen-Ting Chen ◽  
Yueh-Feng Wu ◽  
You-Tzung Chen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Transforming Growth Factor ◽  
Stellate Cell ◽  
Transforming Growth Factor Β1 ◽  
Duct Ligation ◽  
Extracellular Matrix Production ◽  
Matrix Production

Background and objectivesLiver fibrosis (LF) occurs following chronic liver injuries. Currently, there is no effective therapy for LF. Recently, we identified thioredoxin domain containing 5 (TXNDC5), an ER protein disulfide isomerase (PDI), as a critical mediator of cardiac and lung fibrosis. We aimed to determine if TXNDC5 also contributes to LF and its potential as a therapeutic target for LF.DesignHistological and transcriptome analyses on human cirrhotic livers were performed. Col1a1-GFPTg, Alb-Cre;Rosa26-tdTomato and Tie2-Cre/ERT2;Rosa26-tdTomato mice were used to determine the cell type(s) where TXNDC5 was induced following liver injury. In vitro investigations were conducted in human hepatic stellate cells (HSCs). Col1a2-Cre/ERT2;Txndc5fl/fl (Txndc5cKO) and Alb-Cre;Txndc5fl/fl (Txndc5Hep-cKO) mice were generated to delete TXNDC5 in HSCs and hepatocytes, respectively. Carbon tetrachloride treatment and bile duct ligation surgery were employed to induce liver injury/fibrosis in mice. The extent of LF was quantified using histological, imaging and biochemical analyses.ResultsTXNDC5 was upregulated markedly in human and mouse fibrotic livers, particularly in activated HSC at the fibrotic foci. TXNDC5 was induced by transforming growth factor β1 (TGFβ1) in HSCs and it was both required and sufficient for the activation, proliferation, survival and extracellular matrix production of HSC. Mechanistically, TGFβ1 induces TXNDC5 expression through increased ER stress and ATF6-mediated transcriptional regulation. In addition, TXNDC5 promotes LF by redox-dependent JNK and signal transducer and activator of transcription 3 activation in HSCs through its PDI activity, activating HSCs and making them resistant to apoptosis. HSC-specific deletion of Txndc5 reverted established LF in mice.ConclusionsER protein TXNDC5 promotes LF through redox-dependent HSC activation, proliferation and excessive extracellular matrix production. Targeting TXNDC5, therefore, could be a potential novel therapeutic strategy to ameliorate LF.

scholarly journals α2-Adrenergic Receptor in Liver Fibrosis: Implications for the Adrenoblocker Mesedin

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 456 ◽  
Author(s):  
Ute A. Schwinghammer ◽  
Magda M. Melkonyan ◽  
Lilit Hunanyan ◽  
Roman Tremmel ◽  
Ralf Weiskirchen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Transforming Growth Factor Β ◽  
Liver Sinusoidal Endothelial Cells ◽  
Mediated Effects ◽  
Liver Sinusoids ◽  
Endothelial Nitric Oxide

The noradrenergic system is proposed to play a prominent role in the pathogenesis of liver fibrosis. While α1- and β-adrenergic receptors (ARs) are suggested to be involved in a multitude of profibrogenic actions, little is known about α2-AR-mediated effects and their expression pattern during liver fibrosis and cirrhosis. We explored the expression of α2-AR in two models of experimental liver fibrosis. We further evaluated the capacity of the α2-AR blocker mesedin to deactivate hepatic stellate cells (HSCs) and to increase the permeability of human liver sinusoidal endothelial cells (hLSECs). The mRNA of α2a-, α2b-, and α2c-AR subtypes was uniformly upregulated in carbon tetrachloride-treated mice vs the controls, while in bile duct-ligated mice, only α2b-AR increased in response to liver injury. In murine HSCs, mesedin led to a decrease in α-smooth muscle actin, transforming growth factor-β and α2a-AR expression, which was indicated by RT-qPCR, immunocytochemistry, and Western blot analyses. In a hLSEC line, an increased expression of endothelial nitric oxide synthase was detected along with downregulated transforming growth factor-β. In conclusion, we suggest that the α2-AR blockade alleviates the activation of HSCs and may increase the permeability of liver sinusoids during liver injury.

scholarly journals Hepatic Stellate Cell–Macrophage Crosstalk in Liver Fibrosis and Carcinogenesis

2020 ◽  
Vol 40 (03) ◽  
pp. 307-320
Author(s):  
Michitaka Matsuda ◽  
Ekihiro Seki
Keyword(s):  
Liver Fibrosis ◽  
Liver Injury ◽  
Cell Activation ◽  
Stellate Cell ◽  
Tumor Development ◽  
Mesenchymal Cell ◽  
Chronic Liver ◽  
Health Concern ◽  
Chronic Liver Injury ◽  
Fibrotic Liver

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.

scholarly journals Transcriptome and proteome profiling reveal complementary scavenger and immune features of rat liver sinusoidal endothelial cells and liver macrophages

2020 ◽  
Author(s):  
Sabin Bhandari ◽  
Ruomei Li ◽  
Jaione Simón-Santamaría ◽  
Peter McCourt ◽  
Steinar Daae Johansen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Antigen Processing ◽  
Constitutive Expression ◽  
Cell Types ◽  
The Body ◽  
Male Rats ◽  
Molecular Profile ◽  
Immune Functions ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells

Abstract Background: Liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs; liver resident macrophages) form the body´s most effective scavenger cell system for the removal of harmful blood-borne substances, ranging from modified self-proteins to pathogens and xenobiotics. Controversies in the literature regarding the LSEC phenotype pose a challenge when determining distinct functionalities of KCs and LSECs. This may be due to overlapping functions of the two cells, insufficient purification and/or identification of the cells, rapid dedifferentiation of LSECs in vitro, or species differences. We therefore characterized and quantitatively compared expressed gene products of freshly isolated, highly pure LSECs (fenestrated SE-1/FcgRIIb2+) and KCs (CD11b/c+) from Sprague Dawley, Crl:CD(SD), male rats using high throughput mRNA-sequencing and label-free proteomics.Results: We observed a robust correlation between the proteomes and transcriptomes of the two cell types. Integrative analysis of the global molecular profile demonstrated the immunological aspects of LSECs. The constitutive expression of several immune genes and corresponding proteins of LSECs bore some resemblance with the expression in macrophages. LSECs and KCs both expressed high levels of scavenger receptors (SR) and C-type lectins. Equivalent expression of SR-A1 (Msr1), mannose receptor (Mrc1), SR-B1 (Scarb1), and SR-B3 (Scarb2) suggested functional similarity between the two cell types, while functional distinction between the cells was evidenced by LSEC-specific expression of the SRs stabilin-1 (Stab1) and stabilin-2 (Stab2), and the C-type lectins LSECtin (Clec4g) and DC-SIGNR (Clec4m). Many immune regulatory factors were differentially expressed in LSECs and KCs, with one cell predominantly expressing a specific cytokine/chemokine and the other cell the cognate receptor, illustrating the complex cytokine milieu of the sinusoids. Both cells expressed genes and proteins involved in antigen processing and presentation, and lymphocyte co-stimulation. Conclusions: Our findings support complementary and partly overlapping scavenging and immune functions of LSECs and KCs. This highlights the importance of including LSECs in studies of liver immunity, and liver clearance and toxicity of large molecule drugs and nano-formulations.

scholarly journals Inhibition of liver sinusoidal endothelial cells in rats with hepatic fibrosis by injection of VEGF 165 via the inferior vena cava

2021 ◽  
Author(s):  
Zhigang Sun ◽  
Tianyi Dong ◽  
Zhun Zhang ◽  
Tiantian Wang ◽  
Chenyu Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endothelial Cells ◽  
Liver Fibrosis ◽  
Serum Level ◽  
Basement Membranes ◽  
Liver Sinusoidal Endothelial Cells ◽  
Sinusoidal Endothelial Cells ◽  
Transmission Electron

Abstract Background Although VEGF can maintain the normal phenotype of liver sinusoidal endothelial cells (LSECs), it has also been reported that VEGF exacerbates cirrhosis. The role of VEGF in the progression and recovery of cirrhosis has still remained controversial.Methods We established a cirrhotic rat model by thioacetamide that was used as drinking water; besides, 0, 1, 2, and 4 μg VEGF165 were then continuously injected into the rats. The serum level of hyaluronic acid was measured by ELISA at 0, 1, and 4 weeks, separately. Serum levels of ALT, AST, direct bilirubin, indirect bilirubin, and ALB were detected by an automatic biochemical analyzer. In addition, the levels of VEGF165, CD44, MMP9, MMP2, HIF-1α, and endothelin were detected by Western blotting. The expression level of CD44 in LSECs was detected by immunohistochemistry. Changes of fenestrations of LSECs and basement membranes of blood vessels were observed by transmission electron microscopy. Results With the increase of dosage and duration of VEGF treatment, the levels of liver function markers in the serum, the levels of CD44, HIF-1α, hydroxyproline and endothelin were significantly improved. With determination of the serum level of hydroxyproline in the blood, it was disclosed that the mentioned level was markedly decreased. In the Sirius Red staining, the stained red area was gradually reduced. Images captured by transmission electron microscopy also confirmed that the ultrastructure of LSECs tended to be normal.Conclusion VEGF165 can accelerate the resolution of liver fibrosis by promoting fenestration structure formation in LSECs, as well as promoting material exchange between sinusoids and hepatocytes. Our findings may provide a new insight for the study of the role of VEGF in liver fibrosis.

scholarly journals 3D hESC exosomes enriched with miR-6766-3p ameliorates liver fibrosis by attenuating activated stellate cells through targeting the TGFβRII-SMADS pathway

2021 ◽  
Author(s):  
Ning Wang ◽  
Xiajing Li ◽  
Zhiyong Zhong ◽  
Yaqi Qiu ◽  
Shoupei Liu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Cell Activation ◽  
Therapeutic Potential ◽  
Stellate Cell ◽  
Embryonic Stem ◽  
Luciferase Reporter ◽  
Fibrotic Liver

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.

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