Hepatitis C and liver fibrosis

FoxD1 expression identifies a distinct subset of hepatic stellate cells involved in liver fibrosis

Hepatic stellate cells (HSCs) are pericytes of the liver responsible for liver fibrosis and cirrhosis, which are the end stages of chronic liver diseases. TGF-β activates HSCs, leading to the differentiation of myofibroblasts in the process of liver fibrosis. While the heterogeneity of HSCs is appreciated in the fibrotic liver, it remains elusive which HSC subsets mainly contribute to fibrosis. Here, we show that the expression of the pericyte marker FoxD1 specifically marks a subset of HSCs in FoxD1-fate tracer mice. HSCs fate-mapped by FoxD1 were preferentially localized in the portal and peripheral areas of both the homeostatic and fibrotic liver induced by carbon tetrachloride. Furthermore, the deletion of Cbfβ, which is necessary for TGF-β signaling, in FoxD1-expressing cells ameliorated liver fibrosis. Thus, we identified an HSC subset that preferentially responds to liver injuries.

Subpopulation composition of blood T-helpers in hepatitis C patients with genotype 1 or 3

Introduction. Despite advances in treatment, the problem of chronic viral hepatitis C (CVHC) remains very relevant for Russia. There is a debate about which of the most common genotypes in our country: 1 or 3, has a more aggressive course of CVHC. Patients with CVHC exhibit dysfunction of T-cell immunity, many aspects of which remain unclear.

Aim. To research the subpopulation composition of blood T-helpers in patients with genotypes 1 and 3 of chronic viral hepatitis C (CVHC) depending on the severity of clinical and morphological manifestations.

Materials and methods. Clinical, laboratory examination and determination of liver fibrosis by elastometry using the METAVIR scale were performed in 297 patients with CVHC genotype 1, 231 patients with CVHC genotype 3, and 20 healthy individuals in the control group. The study of the subpopulation composition of T-helpers in the blood by flow cytometry (Navios, Beckman Coulter, USA) with the determination of markers CD3, CD4, CD45R0 and CD62L was carried out in 74 patients with CVHC genotype 1, 70 patients with CVHC genotype 3 and 20 people in the control group.

Results. Naive T-helpers (CD3+CD4+CD45RO-CD62L+), T-helpers of central (CD3+CD4+CD45R0+CD62L+) and effector memory (CD3+CD4+CD45R0+CD62L–) in the blood decreased with an increase in the severity of fibrosis and inflammation activity in the liver in both examined groups. In patients with CVHC genotype 3, the content of TEMRA T-helpers (CD3+CD4+CD45R0-CD62L-) in the blood under these conditions sharply decreased (Kruskal – Wallis test, respectively, p = 0.04 and p = 0.02). In patients with CVHC genotype 1, no such patterns were registered (Kruskal – Wallis test, respectively, p = 0.8 and p = 0.87).

Conclusion. A direct correlation was determined between the deterioration of the indicators of the blood T-helpers subpopulation composition with an increase in the severity of fibrosis and inflammation activity in the liver in patients with chronic hepatitis C, which had some differences in patients with genotypes 1 and 3.

P2X4 receptors mediate induction of antioxidants, fibrogenic cytokines and ECM transcripts; in presence of replicating HCV in in vitro setting: An insight into role of P2X4 in fibrosis

Background & aims

Major HCV infections lead to chronic hepatitis, which results in progressive liver disease including fibrosis, cirrhosis and eventually hepatocellular carcinoma (HCC). P2X4 and P2X7 are most widely distributed receptors on hepatocytes.

Methods

Full length P2X4 (1.7kb) (Rattus norvegicus) was sub cloned in mammalian expression vector pcDNA3.1+. Two stable cell lines 293T/P2X4 (experimental) and 293T/ NV or null vector (control) were established. Both cell lines were inoculated with high viral titers human HCV sera and control human sera. Successfully infected cells harvested on day 5 and day 9 of post infection were used for further studies.

Results

The results revealed a significant increase in gene expression of P2X4 on day 5 and day 9 Post -infection in cells infected with HCV sera compared with cells inoculated with control sera. Quantitative real time PCR analysis revealed that HO-1 was significantly upregulated in presence of P2X4 in HCV infected cells (P2X4/HCV) when compared with control NV/HCV cells. A significant decrease was observed in expression of Cu/ZnSOD in presence of P2X4 in HCV infected cells compared to control NV/HCV cells. However, expression of both antioxidants was observed unaltered in cells harvested on day 9 post infection. Gene expression of angiotensin II significantly increased in HCV infected cells in presence of P2X4 on day 5 and day 9 of post infection when compared with control NV/HCV cells. A significant increase in gene expression of TNF-α and TGF-β was observed in HCV infected cells in presence of P2X4 on day 9 post infection in comparison with control (NV/HCV cells). However, gene expression of adipokine leptin was not affected in both experimental (P2X4/HCV) and control (NV/HCV) groups on day 5 and day 9 of post infection. Extracellular matrix proteins, laminin and elastin genes expression also significantly increased in presence of P2X4 (HCV/P2X4) on day 9 of post-infection compared to control group NV/HCV cells.

Conclusion

In conclusion, these findings constitute the evidence that P2X4 receptors in the presence of HCV play a significant role in the regulation of key antioxidant enzymes (HO-1, Cu/ZnSOD), in the induction of proinflammatory. cytokine (TNF-α), profibrotic cytokine (TGF-β) vasoactive cytokine (angiotensin II). P2X4 also increases the expression of extracellular matrix proteins (laminin and elastin) in the presence of HCV.

Cell-to-Cell Communications in Alcohol-Associated Liver Disease

This review covers some important new aspects of the alcohol-induced communications between liver parenchymal and non-parenchymal cells leading to liver injury development. The information exchange between various cell types may promote end-stage liver disease progression and involves multiple mechanisms, such as direct cell-to-cell interactions, extracellular vesicles (EVs) or chemokines, cytokines, and growth factors contained in extracellular fluids/cell culture supernatants. Here, we highlighted the role of EVs derived from alcohol-exposed hepatocytes (HCs) in activation of non-parenchymal cells, liver macrophages (LM), and hepatic stellate cells (HSC). The review also concentrates on EV-mediated crosstalk between liver parenchymal and non-parenchymal cells in the settings of HIV- and alcohol co-exposure. In addition, we overviewed the literature on the crosstalk between cell death pathways and inflammasome activation in alcohol-activated HCs and macrophages. Furthermore, we covered highly clinically relevant studies on the role of non-inflammatory factors, sinusoidal pressure (SP), and hepatic arterialization in alcohol-induced hepatic fibrogenesis. We strongly believe that the review will disclose major mechanisms of cell-to-cell communications pertained to alcohol-induced liver injury progression and will identify therapeutically important targets, which can be used for alcohol-associated liver disease (ALD) prevention.

Pulmonary inflammatory and fibrogenic response induced by graphitized multi-walled carbon nanotube involved in cGAS-STING signaling pathway

Graphitized multi-walled carbon nanotubes (GMWCNTs) are a new type of nanomaterial. Recently, their production and application in biological medicine have grown rapidly. However, GMWCNTs may cause adverse health effects, including the common occupational disease of pulmonary fibrosis. Pulmonary fibrosis is a serious progressive disease that often leads to lung failure, high mortality, and disability, and there is no effective therapy currently available. Therefore, identifying new biomarkers of the disease is important to better understand the disease mechanisms and explore new therapeutic strategies. In this study, 40 μg of GMWCNTs was used to treat mice in vivo by pharyngeal aspiration, and different genes were screened by transcriptome sequencing. Activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) signal pathway had an important effect on the development of pulmonary inflammation and fibrosis. GMWCNTs were then administered to the mice with a STING inhibitor (C-176). Inhibition of STING effectively decreased pulmonary inflammation and fibrosis in mice induced by GMWCNTs. Collectively, activation of the cGAS-STING signaling pathway is involved in GMWCNT-induced pulmonary inflammation and fibrosis in mice.

Ufbp1, a Key Player of Ufm1 Conjugation System, Protects Against Ketosis-Induced Liver Injury via Suppressing Smad3 Activation

The dairy cattle suffer from severe liver dysfunction during the pathogenesis of ketosis. The Ufm1 conjugation system is crucial for liver development and homeostasis. Ufm1 binding protein (Ufbp1) is a putative Ufm1 target and an integral component, but its role in ketosis-induced liver injury is unclear so far. The purpose of this study is to explore the key role of Ufbp1 in liver fibrosis caused by ketosis in vivo and in vitro. Liver tissues were collected from ketotic cows and Ufbp1 conditional knockout (CKO) mice in vivo. However, Ufbp1^–/– mouse embryonic fibroblast cells and Hela cells were used for in vitro validation. Subsequently, various assays were performed to reveal the underlying molecular mechanisms of the Ufbp1 protective effect. In this study, hepatic fibrosis, endoplasmic reticulum (ER) stress, and apoptosis were reported in the liver of ketotic cows, fibrotic markers (alpha-smooth muscle actin, Collagen1) and ER stress markers (glucose-regulated protein 78, CEBP homologous protein) were upregulated remarkably, and the apoptosis-related genes (Bcl2, Bax) were in line with expectations. Interestingly, Ufbp1 expression was almost disappeared, and Smad2/Smad3 protein was largely phosphorylated in the liver of ketotic cows, but Ufbp1 deletion caused Smad3 phosphorylation apparently, rather than Smad2, and elevated ER stress was observed in the CKO mice model. At the cellular level, Ufbp1 deficiency led to serious fibrotic and ER stress response, Smad3 was activated by phosphorylation significantly and then was translocated into the nucleus, whereas p-Smad2 was largely unaffected in embryonic fibroblast cells. Ufbp1 overexpression obviously suppressed Smad3 phosphorylation in Hela cells. Ufbp1 was found to be in full combination with Smad3 using endogenous immunoprecipitation. Taken together, our findings suggest that downregulation or ablation of Ufbp1 leads to Smad3 activation, elevated ER stress, and hepatocyte apoptosis, which in turn causes liver fibrosis. Ufbp1 plays a protective role in ketosis-induced liver injury.

Chitinase 3-like-1, Tolloid-like protein 1, and intergenic gene polymorphisms are predictors for hepatocellular carcinoma development after hepatitis C virus eradication by direct-acting antivirals

Hepatocellular carcinoma (HCC) is a major cause of cancer death in Egypt. There is still a risk for HCC development even after eradicating hepatitis C virus (HCV) by direct-acting antivirals (DAAs). Chitinase-3-like-protein-1 (CHI3L1), a biomarker for predicting many diseases, plays an essential role in inflammation, angiogenesis, and antiapoptosis. Tolloid-like protein 1 (TLL1) may be involved in hepatic fibrogenesis and carcinogenesis. This study aimed to determine the role and combined effect of CHI3L1 (rs880633), TLL1 (rs1503298), and an intergenic (rs597533) polymorphisms on the risk of developing HCC in Egyptian patients after achieving sustained virological response (SVR) by DAAs. Blood samples were collected from 68 HCC patients, 77 non-HCC subjects, and 80 healthy controls. The DNA was extracted and analyzed for rs880633, rs1503298, and rs597533 using Genotyping TaqMan™ assay. The result of the present study showed a significant difference in genotypes and alleles frequencies in both (rs880633) and (rs597533) in HCC group as compared to healthy control and also as compared to the non-HCC group. However, regarding to (rs1503298) genotypes and alleles between the HCC and non-HCC groups, there were no significant differences. Combined polymorphism in more than one gene simultaneously showed a higher risk to HCC after SVR than an individual locus. Both allelic and genotypic variations of the CHI3L1 gene (rs880633) and an intergenic (rs597533) seemed to be significant predictors confirming a great risk for HCC susceptibility in Egyptian patients achieved SVR. Patients with a polymorphism in more than one gene showed an increased risk to HCC after SVR rather than individual locus.

Long-term outcomes after curative resection of HCV-positive versus non-hepatitis related hepatocellular carcinoma: an international multi-institutional analysis

BACKGROUND

To define the chronological changes of long-term survival among patients with non-hepatitis-related hepatocellular carcinoma (Non-Hep-HCC) versus hepatitis C-related HCC (HCV-HCC) over the last two decades.

METHODS

Patients who underwent curative-intent resection for HCC between 2000 and 2017 were identified from an international multi-institutional database. Overall (OS) and recurrence-free survival (RFS) were analyzed and compared among Non-Hep-HCC versus HCV-HCC patients. Propensity score matching (PSM) was utilized to mitigate residual bias.

RESULTS

Among 617 patients, 196 (31.8%) patients had HCV-HCC, whereas 421 (68.2%) patients had Non-Hep-HCC. While patients with HCV-HCC had an improvement in OS over time (5-year OS, 2000-2009 55% vs. 2010-2017 67%, p = 0.034), OS among patients with Non-Hep-HCC remain unchanged (5-year OS, 2000-2009 53% vs. 2010-2017 52%, p = 0.905). In the matched cohort, patients with HCV-HCC had a worse OS versus patients with Non-Hep-HCC during 2000 and 2009 (5-year OS, 12% vs. 63%, p = 0.029), but significantly better OS from 2010 to 2017 than patients with Non-Hep-HCC (5-year OS, 86% vs. 73%, p = 0.035). The recurrence timing, patterns and re-treatments were comparable among Non-Hep-HCC and HCV-HCC patients.

CONCLUSION

While OS of patients with HCV-HCC improved over time, the long-term survival of patients with Non-Hep-HCC patients remained unchanged and was more unfavorable.

Deltamethrin induces liver fibrosis in quails via activation of the TGF-β1/Smad signaling pathway

Deltamethrin (DLM) is an important member of the pyrethroid pesticide family, and its widespread use has led to serious environmental and health problems. Exposure to DLM causes pathological changes in the liver of animals and humans and can lead to liver fibrosis. However, the mechanism of DLM-induced liver fibrosis remains unclear. Therefore, to address its potential molecular mechanisms, we used both in vivo and in vitro methods. Quails were treated in vivo by intragastric administration of different concentrations of DLM (0, 15, 30, or 45 mg kg^-1), and the chicken liver cancer cell line LMH was treated in vitro with various doses of DLM (0, 50, 200, or 800 μg mL^-1). We found that DLM treatment in vivo induced liver fibrosis in a dose-dependent manner through the promotion of oxidative stress, activation of transforming growth factor-β1 (TGF-β1) and phosphorylation of Smad2/3. Treatment of LMH cells with different concentrations of DLM similarly induced oxidative stress and also decreased cell viability. Collectively, our study demonstrates that DLM-induced liver fibrosis in quails occurs via activation of the TGF-β1/Smad signaling pathway.

Origin and role of hepatic myofibroblasts in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the second leading cause of cancer-related death worldwide. Fibrosis and cirrhosis are important risk factors for the development of HCC. Hepatic myofibroblasts are the cells responsible for extracellular matrix deposition, which is the hallmark of liver fibrosis. It is believed that myofibroblasts are predominantly derived from hepatic stellate cells (HSCs), also known as Ito cells. Nevertheless, depending on the nature of insult to the liver, it is thought that myofibroblasts may also originate from a variety of other cell types such as the portal fibroblasts (PFs), fibrocytes, hepatocytes, hepatic progenitor cells (HPCs), and mesothelial cells. Liver myofibroblasts are believed to transform into cancer-associated fibroblasts (CAFs) while HCC is developing. There is substantial evidence suggesting that activated HSCs (aHSCs)/cancer-associated fibroblasts (CAFs) may play an important role in HCC initiation and progression. In this paper, we aim to review current literature on cellular origins of myofibroblasts with a focus on hepatitis B virus (HBV)- and hepatitis C virus (HCV)-induced hepatic fibrosis. We also address the role of aHSCs/CAFs in HCC progression through the regulation of immune cells as well as mechanisms of evolvement of drug resistance.

Origin and role of hepatic myofibroblasts in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the second leading cause of cancer-related death worldwide. Fibrosis and cirrhosis are important risk factors for the development of HCC. Hepatic myofibroblasts are the cells responsible for extracellular matrix deposition, which is the hallmark of liver fibrosis. It is believed that myofibroblasts are predominantly derived from hepatic stellate cells (HSCs), also known as Ito cells. Nevertheless, depending on the nature of insult to the liver, it is thought that myofibroblasts may also originate from a variety of other cell types such as the portal fibroblasts (PFs), fibrocytes, hepatocytes, hepatic progenitor cells (HPCs), and mesothelial cells. Liver myofibroblasts are believed to transform into cancer-associated fibroblasts (CAFs) while HCC is developing. There is substantial evidence suggesting that activated HSCs (aHSCs)/cancer-associated fibroblasts (CAFs) may play an important role in HCC initiation and progression. In this paper, we aim to review current literature on cellular origins of myofibroblasts with a focus on hepatitis B virus (HBV)- and hepatitis C virus (HCV)-induced hepatic fibrosis. We also address the role of aHSCs/CAFs in HCC progression through the regulation of immune cells as well as mechanisms of evolvement of drug resistance.

A Newly Established Murine Cell Line as a Model for Hepatocellular Cancer in Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) has become a major risk factor for hepatocellular cancer (HCC) due to the worldwide increasing prevalence of obesity. However, the pathophysiology of NASH and its progression to HCC is incompletely understood. Thus, the aim of this study was to generate a model specific NASH-derived HCC cell line. A murine NASH-HCC model was conducted and the obtained cancer cells (N-HCC25) were investigated towards chromosomal aberrations, the expression of cell type-specific markers, dependency on nutrients, and functional importance of mTOR. N-HCC25 exhibited several chromosomal aberrations as compared to healthy hepatocytes. Hepatocytic (HNF4), EMT (Twist, Snail), and cancer stem cell markers (CD44, EpCAM, CK19, Sox9) were simultaneously expressed in these cells. Proliferation highly depended on the supply of glucose and FBS, but not glutamine. Treatment with a second generation mTOR inhibitor (KU-0063794) resulted in a strong decrease of cell growth in a dose-dependent manner. In contrast, a first generation mTOR inhibitor (Everolimus) only slightly reduced cell proliferation. Cell cycle analyses revealed that the observed growth reduction was most likely due to G₁/G₀ cell cycle arrest. These results indicate that N-HCC25 is a highly proliferative HCC cell line from a NASH background, which might serve as a suitable in vitro model for future investigations of NASH-derived HCC.

Association of TGF-ß1 polymorphisms and chronic hepatitis C infection: a Meta-analysis

Background

Although several researches have reported the connection between the transforming growth factor-beta 1 (TGF-β1) gene polymorphisms and chronic hepatitis C virus (HCV) infection, the conclusions of these studies were not always consistent. Here, this paper proposed a meta-analysis to evaluate whether the TGF-ß1 gene polymorphisms, −509C/T (rs1800469), codon 10 T/C (rs1982073) and codon 25G/C (rs1800471), were associated with chronic HCV infection.

Methods

The summary odds ratios (ORs) of chronic HCV infected patients and controls with all SNPs were obtained by adaptive fixed or random effect model. A series of statistical tools were employed to guarantee the accuracy of related pooling ORs, including the Hardy-Weinberg equilibrium (HWE) test, sensitivity analysis and publication bias test.

Results

This paper analyzed 18 case-control studies in 17 articles which totally contains 2718 chronic HCV infection cases corresponding to 1964 controls. The results of the meta-analysis indicated that the −509C/T polymorphism effected an increased risk of chronic HCV infection in all gene models. More specifically by ethnicity stratification, the Egyptians shared the similar association with the above overall study. Moreover, the meta-fusion of healthy control studies showed that − 509 T allele carriers (TT + TA) had nearly 2.00 and 3.36 fold higher risk of chronic HCV infection in the total and Egyptian populations, respectively (OR = 2.004, 95% CI = 1.138–3.528, P = 0.016; OR = 3.363, 95% CI = 1.477–7.655, P = 0.004, respectively). However, our meta-analysis did not find any significant association between the codon 10 T/C or codon 25G/C polymorphisms and chronic HCV infection.

Conclusions

Our results suggested that the TGF-ß1–509C/T polymorphism may effect an increased risk of chronic HCV infection, especially in Egyptian population.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4390-8) contains supplementary material, which is available to authorized users.

Fibrogenic Gene Expression in Hepatic Stellate Cells Induced by HCV and HIV Replication in a Three Cell Co-Culture Model System

Retrospective studies indicate that co-infection of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) accelerates hepatic fibrosis progression. We have developed a co-culture system (MLH) comprising primary macrophages, hepatic stellate cells (HSC, LX-2), and hepatocytes (Huh-7), permissive for active replication of HCV and HIV, and assessed the effect of these viral infections on the phenotypic changes and fibrogenic gene expression in LX-2 cells. We detected distinct morphological changes in LX-2 cells within 24 hr post-infection with HCV, HIV or HCV/HIV in MLH co-cultures, with migration enhancement phenotypes. Human fibrosis microarrays conducted using LX-2 cell RNA derived from MLH co-culture conditions, with or without HCV and HIV infection, revealed novel insights regarding the roles of these viral infections on fibrogenic gene expression in LX-2 cells. We found that HIV mono-infection in MLH co-culture had no impact on fibrogenic gene expression in LX-2 cells. HCV infection of MLH co-culture resulted in upregulation (>1.9x) of five fibrogenic genes including CCL2, IL1A, IL1B, IL13RA2 and MMP1. These genes were upregulated by HCV/HIV co-infection but in a greater magnitude. Conclusion: Our results indicate that HIV-infected macrophages accelerate hepatic fibrosis during HCV/HIV co-infection by amplifying the expression of HCV-dependent fibrogenic genes in HSC.

Tolloid-like 1 genetic variants determine fibrosis regression in chronic hepatitis C patients with curative antivirals

Hepatitis C virus (HCV) eradication by antivirals promote fibrosis modification. Whether host genetics determined fibrosis regression in chronic hepatitis C (CHC) patients with sustained virological response (SVR) is to be determined. One hundred and fifty-six SVR patients with paired liver biopsy before and after antivirals were enrolled. Host genetic factors including single nucleotide polymorphism rs17047200 of tolloid-like 1(TLL-1) were analyzed for their association with fibrosis modification. The proportions of improved, unchanged and worsening fibrotic stags were 39.1% (n = 61), 39.1% (n = 61), and 21.8% (n = 34), respectively. The rate of annual fibrotic improvement was 0.16 ± 0.79. There was a significant trend of increased fibrotic improvement rate in patients from F01 to F4 (P < 0.001). However, the rate of improvement seemed more limited in cirrhotic patients among those with advanced liver disease. Patients with fibrotic improvement had a significantly higher proportion of TLL-1 rs17047200 AA genotype compared to those without (92.5% vs. 79.3%, p = 0.039). Logistic regression analysis revealed that the TLL-1 rs17047200 AA genotype was the only independent factor associated with fibrosis improvement (odds ratio/95% confidence intervals: 3.2/1.01-10.12, p = 0.047). Compared with TLL-1 rs17047200 non-AA carriers, a significantly higher proportion of fibrosis improvement in AA genotype carriers was observed among patients with F0-2 (33.3% vs. 0%, p = 0.005) but not with F34 (70% vs. 80%, p = 1). We concluded that TLL-1 genetic variants determined fibrotic improvement in CHC with curative antivirals, particularly in patients with mild liver disease.

Genetic diversity of Hepatitis C Virus in Pakistan using Next Generation Sequencing

BACKGROUND

In Pakistan, HCV disease is considered a major public health issue with about 10-17 million people suffering with this infection and rate is increasing every day without any hindrance. The currently available Pyrosequencing approach used to analyze complex viral genomes as it can determine minor variants. It is crucial to understand viral evolution and quasispecies diversity in complex viral strains.

OBJECTIVES

To assess genetic diversity in patients with HCV using Next Generation Sequencing (NGS) and compare nucleotide diversity of genotype 3a with respect to other genotypes.

STUDY DESIGN

Intra-host viral diversity of HCV was determined using NGS from 13 chronically HCV infected individuals. NGS of three different regions (E2 (HVR1), NS3 and NS5B) of HCV-3a allowed for a comprehensive analysis of the viral population.

RESULT

Phylogenetic analysis of different HCV genes revealed great variability within the Pakistani population. The average nucleotide diversity for HVR1, NS3 and NS5B was 0.029, 0.011 and 0.010 respectively.

CONCLUSION

Our findings clearly indicate that patient-2 greater quasispecies heterogeneity than other patients of same genotype-3a using phylogenetic and one step network analyses. Initially phylogenetic analysis of these three genes showed that genotype 3a samples have greater genetic diversity. However, no significant difference was determined when nucleotide variability of genotype 3a compared with other genotypes (1a, 1b, 2a & 4a).

The balancing act of the liver: tissue regeneration versus fibrosis

Epithelial cell loss alters a tissue's optimal function and awakens evolutionarily adapted healing mechanisms to reestablish homeostasis. Although adult mammalian organs have a limited regeneration potential, the liver stands out as one remarkable exception. Following injury, the liver mounts a dynamic multicellular response wherein stromal cells are activated in situ and/or recruited from the bloodstream, the extracellular matrix (ECM) is remodeled, and epithelial cells expand to replenish their lost numbers. Chronic damage makes this response persistent instead of transient, tipping the system into an abnormal steady state known as fibrosis, in which ECM accumulates excessively and tissue function degenerates. Here we explore the cellular and molecular switches that balance hepatic regeneration and fibrosis, with a focus on uncovering avenues of disease modeling and therapeutic intervention.

Activation of hepatic stellate cells by the ubiquitin C-terminal hydrolase 1 protein secreted from hepatitis C virus-infected hepatocytes

Hepatitis C virus (HCV) infection of hepatocytes promotes liver fibrosis by activation of hepatic stellate cells (HSCs) and excessive deposition of extracellular matrix in liver tissue. Whether or not host factors released from the HCV-infected hepatocytes play role in HSCs activation is unclear. In this study, HSCs were activated by the conditioned medium derived from HCV replicon cells. Secretomic profiling of HCV replicon cells and the parental Huh7 cells revealed ubiquitin carboxy-terminal hydrolase L1 (UCHL1) as a novel secreted protein from HCV-infected hepatocytes. UCHL1 expression in hepatocytes was induced by HCV infection. UCHL1 was expressed in the liver and found in the plasma of patients with chronic hepatitis C. Molecular analysis by use of the anti-UCHL1 neutralization antibody and purified UCHL1 protein showed that secreted UCHL1 protein was bound to the cell surface of HSCs and activated JNK signaling leading to overexpression of alpha-smooth muscle actin and the activation of HSCs. These results provide further for understanding the underlying mechanism in HCV-mediated hepatic fibrogenesis.

Signalome-wide assessment of host cell response to hepatitis C virus

Host cell signalling during infection with intracellular pathogens remains poorly understood. Here we report on the use of antibody microarray technology to detect variations in the expression levels and phosphorylation status of host cell signalling proteins during hepatitis C virus (HCV) replication. Following transfection with HCV RNA, the JNK and NF-κB pathways are suppressed, while the JAK/STAT5 pathway is activated; furthermore, components of the apoptosis and cell cycle control machineries are affected in the expression and/or phosphorylation status. RNAi-based hit validation identifies components of the JAK/STAT, NF-κB, MAPK and calcium-induced pathways as modulators of HCV replication. Selective chemical inhibition of one of the identified targets, the JNK activator kinase MAP4K2, does impair HCV replication. Thus this study provides a comprehensive picture of host cell pathway mobilization by HCV and uncovers potential therapeutic targets. The strategy of identifying targets for anti-infective intervention within the host cell signalome can be applied to any intracellular pathogen.

Development of antiviral strategies depends on an understanding of virus–host interactions. Here, using HCV, Haqshenas et al. show that antibody microarray combined with a targeted siRNA screen can be a powerful tool to identify cellular signalling pathways that are important for virus replication.

Genome-Wide Association Study Identifies TLL1 Variant Associated With Development of Hepatocellular Carcinoma After Eradication of Hepatitis C Virus Infection

BACKGROUND & AIMS

There is still a risk for hepatocellular carcinoma (HCC) development after eradication of hepatitis C virus (HCV) infection with antiviral agents. We investigated genetic factors associated with the development of HCC in patients with a sustained virologic response (SVR) to treatment for chronic HCV infection.

METHODS

We obtained genomic DNA from 457 patients in Japan with a SVR to interferon-based treatment for chronic HCV infection from 2007 through 2015. We conducted a genome-wide association study (GWAS), followed by a replication analysis of 79 candidate single nucleotide polymorphisms (SNPs) in an independent set of 486 patients in Japan. The study end point was HCC diagnosis or confirmation of lack of HCC (at follow-up examinations until December 2014 in the GWAS cohort, and until January 2016 in the replication cohort). We collected clinical and laboratory data from all patients. We analyzed expression levels of candidate gene variants in human hepatic stellate cells, rats with steatohepatitis caused by a choline-deficient L-amino acid-defined diet, and a mouse model of liver injury caused by administration of carbon tetrachloride. We also analyzed expression levels in liver tissues of patients with chronic HCV infection with different stages of fibrosis or tumors vs patients without HCV infection (controls).

RESULTS

We found a strong association between the SNP rs17047200, located within the intron of the tolloid like 1 gene (TLL1) on chromosome 4, and development of HCC; there was a genome-wide level of significance when the results of the GWAS and replication study were combined (odds ratio, 2.37; P = 2.66 × 10^-8). Multivariate analysis showed rs17047200 AT/TT to be an independent risk factor for HCC (hazard ratio, 1.78; P = .008), along with male sex, older age, lower level of albumin, advanced stage of hepatic fibrosis, presence of diabetes, and higher post-treatment level of α-fetoprotein. Combining the rs17047200 genotype with other factors, we developed prediction models for HCC development in patients with mild or advanced hepatic fibrosis. Levels of TLL1 messenger RNA (mRNA) in human hepatic stellate cells increased with activation. Levels of Tll1 mRNA increased in liver tissues of rodents with hepatic fibrogenesis compared with controls. Levels of TLL1 mRNA increased in liver tissues of patients with progression of fibrosis. Gene expression levels of TLL1 short variants, including isoform 2, were higher in patients with rs17047200 AT/TT.

CONCLUSIONS

In a GWAS, we identified the association between the SNP rs17047200, within the intron of TLL1, and development of HCC in patients who achieved an SVR to treatment for chronic HCV infection. We found levels of Tll1/TLL1 mRNA to be increased in rodent models of liver injury and liver tissues of patients with fibrosis, compared with controls. We propose that this SNP might affect splicing of TLL1 mRNA, yielding short variants with high catalytic activity that accelerates hepatic fibrogenesis and carcinogenesis. Further studies are needed to determine how rs17047200 affects TLL1 mRNA levels, splicing, and translation, as well as the prevalence of this variant among other patients with HCC. Tests for the TLL1 SNP might be used to identify patients at risk for HCC after an SVR to treatment of HCV infection.

APASL consensus statements and recommendations for hepatitis C prevention, epidemiology, and laboratory testing

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on "APASL consensus statements and recommendations for management of hepatitis C" in March 2015 to revise the "APASL consensus statements and management algorithms for hepatitis C virus infection" (Hepatol Int 6:409-435, 2012). The working party consisted of expert hepatologists from the Asian-Pacific region gathered at the Istanbul Congress Center, Istanbul, Turkey on 13 March 2015. New data were presented, discussed, and debated during the course of drafting a revision. Participants of the consensus meeting assessed the quality of the cited studies. The finalized recommendations for hepatitis C prevention, epidemiology, and laboratory testing are presented in this review.

Circulating let-7 levels in plasma and extracellular vesicles correlate with hepatic fibrosis progression in chronic hepatitis C

The goal of this study was to determine whether an association exists between circulating microRNA (miRNA) levels and disease progression in chronic hepatitis C (CHC), whether plasma or extracellular vesicles (EVs) were optimal for miRNA measurement and their correlation with hepatic miRNA expression, and the mechanistic plausibility of this association. We studied 130 CHC patients prospectively followed over several decades. A comprehensive miRNA profile in plasma using microarray with 2578 probe sets showed 323 miRNAs differentially expressed between healthy individuals and CHC patients, but only six that distinguished patients with mild versus severe chronic hepatitis. Eventually, let-7a/7c/7d-5p and miR-122-5p were identified as candidate predictors of disease progression. Cross-sectional analyses at the time of initial liver biopsy showed that reduced levels of let-7a/7c/7d-5p (let-7s) in plasma were correlated with advanced histological hepatic fibrosis stage and other fibrotic markers, whereas miR-122-5p levels in plasma were positively correlated with inflammatory activity, but not fibrosis. Measuring let-7s levels in EVs was not superior to intact plasma for discriminating significant hepatic fibrosis. Longitudinal analyses in 60 patients with paired liver biopsies showed that let-7s levels in plasma markedly declined over time in parallel with fibrosis progression. However, circulating let-7s levels did not parallel those in the liver.

CONCLUSION

Of all miRNAs screened, the let-7 family showed the best correlation with hepatic fibrosis in CHC. A single determination of let-7s levels in plasma did not have superior predictive value for significant hepatic fibrosis compared with that of fibrosis-4 index, but the rate of let-7s decline in paired longitudinal samples correlated well with fibrosis progression. Pathway analysis suggested that low levels of let-7 may influence hepatic fibrogenesis through activation of transforming growth factor β signaling in hepatic stellate cells. (Hepatology 2016;64:732-745).

Effects of recombinant human adenovirus-p53 on the regression of hepatic fibrosis

Hepatic fibrosis is a scarring process that may progress to hepatic cirrhosis and even hepatic carcinoma if left untreated. Hepatic stellate cells (HSCs) play essential roles in the development of hepatic fibrosis. The tumor suppressor protein p53 is a transcription factor that is involved in cell proliferation, cell cycle regulation, apoptosis and DNA repair. Recombinant human adenovirus-p53 (Ad-p53) has been demonstrated to act as a promising antitumor gene therapy in various types of cancer. However, there is limited infomration regarding the therapeutic effect of Ad-p53 on the regression of hepatic fibrosis. In order to examine the underlying molecular mechanism responsible for the effects of Ad-p53 on HSCs, a rat model of hepatic fibrosis was established and HSC-T₆ cells were cultured under different conditions. The expression of p53, transforming growth factor (TGF-β1) and α-smooth muscle actin (α-SMA), which is a marker of activated HSCs, was detected by immunohistochemical assays and RT-qPCR. In vitro, five different concentrations (1×10⁶, 5×10⁶, 1×10⁷, 2×10⁷ and 5×10⁷ PFU/ml) of Ad-p53 were selected for use in the MTT assay to analyze the proliferation of HSCs at 0, 24, 48 and 72 h. Flow cytometric analysis was applied to determine the effect of three different concentrations of Ad-p53 (5×10⁶, 1×10⁷ and 2×10⁷ PFU/ml) on the cell cycle and the apoptosis of HSC-T₆ cells at 24 and 48 h. The results of immunohistochemical studies and RT-qPCR showed that Ad-p53 upregulated the expression of p53, and downregulated the expression of TGF-β1 and α-SMA. The MTT assay revealed that when treated with various doses of Ad-p53, the proliferation of HSCs was inhibited within a certain range of concentrations and time periods. Analysis of flow cytometric data showed that Ad-p53 arrested the cell cycle in G1 phase and significantly induced apoptosis. Taken together, these findings suggest that Ad-p53 promotes apoptosis and inhibits the proliferation of HSCs in a time- and dose-dependent manner by modulating the expression of p53, TGF-β1 and α-SMA.

Cancer-associated fibroblasts in hepatocellular carcinoma

The hepatic stellate cells in the liver are stimulated sustainably by chronic injury of the hepatocytes, activating myofibroblasts, which produce abundant collagen. Myofibroblasts are the major source of extracellular proteins during fibrogenesis, and may directly, or secreted products, contribute to carcinogenesis and tumor progression. Cancer-associated fibroblasts (CAFs) are one of the components of the tumor microenvironment that promote the proliferation and invasion of cancer cells by secreting various growth factors and cytokines. CAFs crosstalk with cancer cells stimulates tumor progression by creating a favorable microenvironment for progression, invasion, and metastasis through the epithelial-mesenchymal transition. Basic studies on CAFs have advanced, and the role of CAFs in tumors has been elucidated. In particular, for hepatocellular carcinoma, carcinogenesis from cirrhosis is a known fact, and participation of CAFs in carcinogenesis is supported. In this review, we discuss the current literature on the role of CAFs and CAF-related signaling in carcinogenesis, crosstalk with cancer cells, immunosuppressive effects, angiogenesis, therapeutic targets, and resistance to chemotherapy. The role of CAFs is important in cancer initiation and progression. CAFtargeted therapy may be effective for suppression not only of fibrosis but also cancer progression.

HCV derived from sera of HCV-infected patients induces pro-fibrotic effects in human primary fibroblasts by activating GLI2

Hepatitis C virus (HCV) infection is a leading cause of liver fibrosis, especially in developing countries. The process is characterized by the excess accumulation of ECM that may lead, over time, to hepatic cirrhosis, liver failure and also to hepatocarcinoma. The direct role of HCV in promoting fibroblasts trans-differentiation into myofibroblasts, the major fibrogenic cells, has not been fully clarified. In this study, we found that HCV derived from HCV-infected patients infected and directly induced the trans-differentiation of human primary fibroblasts into myofibroblasts, promoting fibrogenesis. This effect correlated with the activation of GLI2, one of the targets of Hedgehog signaling pathway previously reported to be involved in myofibroblast generation. Moreover, GLI2 activation by HCV correlated with a reduction of autophagy in fibroblasts, that may further promoted fibrosis. GLI2 inhibition by Gant 61 counteracted the pro-fibrotic effects and autophagy inhibition mediated by HCV, suggesting that targeting HH/GLI2 pathway might represent a promising strategy to reduce the HCV-induced fibrosis.

Diagnostic value of optimised real-time sonoelastography in the assessment of liver fibrosis in chronic hepatitis B and C

Aim

To optimise the method of real-time elastography (RTE) in the assessment of liver fibrosis using an in-house prepared method for elastogram analysis, as well as a semiquantitative analysis based on newly introduced parameters.

Material and methods

Sonoelastography was performed in 94 patients with various degrees of liver fibrosis and also in 25 healthy volunteers. As a reference method for diagnostic efficacy of sonoelastography-based parameters used for the assessment of fibrosis degree in patients with chronic B and C hepatitis, a liver biopsy was used. Patient’s elastograms were analysed using in-house prepared software, Pixel Count, calculating two semiquantitative parameters: mean stiffness fraction (MSF%) and intrinsic stiffness ratio (ISR).

Results

Statistically significant differences between distributions of the above presented parameters for different degrees of liver fibrosis were revealed. Indices of diagnostic efficacy for detection of significant liver fibrosis (F ≥ 2) using MSF% amounted to: sensitivity – 76%, specificity – 87% and ISR: 81% and 87%, respectively. Sensitivity of both parameters in detection of cirrhosis (F = 4) was equal to 88% and specificity amounted to: for MSF% – 84% and ISR – 86%. Interobserver reproducibility determined for both of the above parameters was high, intraclass correlation coefficients (ICC) were 0.91 for MSF% and 0.93 for ISR.

Conclusions

Real-time elastography applied in this study, using in-house prepared Pixel Count software, provided good reproducibility and diagnostic efficacy, especially specificity, in the assessment of liver fibrosis degree.

Hepatitis C virus infection stimulates transforming growth factor-β1 expression through up-regulating miR-192

The objective of this study was to determine the molecular mechanisms underlying chronic liver injury and fibrosis caused by hepatitis C virus (HCV). This study revealed that miR-192 expreßsion was induced by HCV infection without affecting viral replication. However, viral-induced miR-192 up-regulated transforming growth factor-ß1 (TGF-ß1) expreßsion in liver cells at transcriptional level. TGF-ß1 stimulation by HCV-induced miR-192 was caused through ZEB1 down-regulation and TGF-ß1 increased miR-192 level via positive feedback pathway. Increase in miR-192 expreßsion by HCV infection was due to HCV core protein released and/or expressed by viral infection. TGF-ß1 promoter activity was also increased by HCV core protein in liver cells. Taken together, HCV infection resulted in increased TGF-ß1 transcription in hepatocytes through ZEB1 down-regulation by HCV core-mediated miR-192 stimulation. Importantly, miR-192 inhibition with anti-miR-192 rescued ZEB1 expression down-regulated by HCV infection, thus reducing the level of TGF-ß1 expression increased by HCV infection in hepatocytes. These results suggest a novel mechanism of HCV-mediated liver fibrogenesis with miR-192 being a potential molecular target to ameliorate viral pathogenesis.

Immunohistochemical study of hepatic fibropoiesis associated with canine visceral leishmaniasis

Hepatic fibropoiesis has been confirmed in canine visceral leishmaniasis. In fibrotic disease, hepatic stellate cells (HSC) play an important role in fibropoiesis, undergoing activation by TGF-β to acquire characteristics of myofibroblasts. These cells show extensive capacity for proliferation, motility, contractility, collagen synthesis and extracellular matrix component synthesis. The aim of this work was to identify markers of HSC activation in 10 symptomatic and 10 asymptomatic dogs naturally infected with Leishmania (Leishmania) infantum. Eight uninfected dogs were used as controls. Alpha-actin (α-SMA), vimentin and cytokeratin were investigated by immunohistochemistry as HSC markers. The cytokine TGF-β in tissue was also evaluated by immunohistochemistry. All infected dogs showed higher numbers of reticular fibres than controls. Fibropoiesis found in infected dogs was always associated with the presence of parasites and chronic granulomatous hepatitis. Positive correlation was found among fibropoiesis, parasite tissue load and expression of α-SMA. There was no correlation between fibropoiesis, vimentin and cytokeratin markers. The expression of cytokine TGF-β was higher in infected dogs than in controls, but not significantly different between symptomatic and asymptomatic dogs. These results confirm previous work describing the intense hepatic fibropoiesis in dogs naturally infected with Leishmania infantum, but now associated them with overexpression of TGF-β, where α-SMA may be a superior marker for activated HSC cells in CVL.

Effect of Antiviral Therapy on Serum Activity of Angiotensin Converting Enzyme in Patients with Chronic Hepatitis C

Introduction:

Renin-angiotenzin system (RAS) is frequently activated in patients with chronic liver disease. Angiotenzin - II (AT-II), produced by angiotenzin converting enzyme (ACE), has many physiological effects, including an important role in liver fibrogenesis. Combined antiviral therapy with PEG-IFN and ribavirin besides its antiviral effect also leads to a reduction in liver parenchyma fibrosis.

Aim of the study:

Determining the value of ACE in serum of patients with chronic hepatitis C before and after combined antiviral therapy, as well as the value of ACE activities in sera of the control group.

Materials and methods:

We studied 50 patients treated at Gastroenterohepatology Department, in the time-period of four years. Value of ACE in serum was determined by Olympus AU 400 device, with application of kit “Infinity TN ACE Liquid Stable Reagent”. HCV RNA levels in sera were measured by real time PCR. HCV RNA test was performed with modular analysis of AMPLICOR and COBAS AMPLICOR HCV MONITOR test v2.0, which has proved infection and was used for quantification of the viruses and monitoring of the patients’ response to therapy. Liver histology was evaluated in accordance with the level of necroinflammation activity and stage of fibrosis.

Results:

Serum activities of ACE in chronic hepatitis C patients is statistically higher than the values in the control group (p=0.02). Antiviral therapy in chronic hepatitis C patients statistically decreases serum activities of ACE (p= 0.02) and indirectly affects fibrogenesis of the liver parenchyma. Correlation between ACE and ALT activity after the therapy was proved (0.3934).

Conclusion:

Our findings suggest that the activity of ACE in serum is a good indirect parameter of the liver damage, and could be used as an indirect prognostic factor of the level of liver parenchyma damage. Serum activity of ACE can be used as a parameter for non-invasive assessment of intensity of liver damage.

Hepatitis C Virus-Induced Monocyte Differentiation Into Polarized M2 Macrophages Promotes Stellate Cell Activation via TGF-β

BACKGROUND & AIMS

Monocyte and macrophage (MΦ) activation contributes to the pathogenesis of chronic hepatitis C virus (HCV) infection. Disease pathogenesis is regulated by both liver-resident MΦs and monocytes recruited as precursors of MΦs into the damaged liver. Monocytes differentiate into M1 (classic/proinflammatory) or M2 (alternative/anti-inflammatory) polarized MΦs in response to tissue microenvironment. We hypothesized that HCV-infected hepatoma cells (infected with Japanese fulminant hepatitis-1 [Huh7.5/JFH-1]) induce monocyte differentiation into polarized MΦs.

METHODS

Healthy human monocytes were co-cultured with Huh7.5/JFH-1 cells or cell-free virus for 7 days and analyzed for MΦ markers and cytokine levels. A similar analysis was performed on circulating monocytes and liver MΦs from HCV-infected patients and controls.

RESULTS

Huh7.5/JFH-1 cells induced monocytes to differentiate into MΦs with increased expression of CD14 and CD68. HCV-MΦs showed M2 surface markers (CD206, CD163, and Dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN)) and produced both proinflammatory and anti-inflammatory cytokines. HCV-induced early interleukin 1β production promoted transforming growth factor (TGF)β production and MΦ polarization to an M2 phenotype. TGF-β secreted by M2-MΦ led to hepatic stellate cell activation indicated by increased expression of collagen, tissue inhibitor of metalloproteinase 1, and α-smooth muscle actin. In vivo, we observed a significant increase in M2 marker (CD206) expression on circulating monocytes and in the liver of chronic HCV-infected patients. Furthermore, we observed the presence of a unique collagen-expressing CD14⁺CD206⁺ monocyte population in HCV patients that correlated with liver fibrosis.

CONCLUSIONS

We show an important role for HCV in induction of monocyte differentiation into MΦs with a mixed M1/M2 cytokine profile and M2 surface phenotype that promote stellate cell activation via TGF-β. We also identified circulating monocytes expressing M2 marker and collagen in chronic HCV infection that can be explored as a biomarker.

Common Variants of the Prostaglandin-Endoperoxide Synthase 2 Gene and Hepatocellular Carcinoma Susceptibility

Hepatocellular carcinoma (HCC) is a heterogeneous disease with substantial genetic constitution. Previous work has evaluated the effect of prostaglandin-endoperoxide synthase 2 (PTGS2) variants (-765G/C, -1195A/G, and +8473T/C) on the development of HCC, but the conclusions are inconsistent. We conducted a meta-analysis in this work. Data from 7 case-control studies were combined to assess the association between PTGS2 variants and HCC. The risk of HCC (OR and 95% CI) was estimated using either the fixed- or the random-effects model according to the Q test. No significant association was identified for -765G/C and +8473T/C. However, we identified a significantly decreased risk in relation to the GG genotype of -1195A/G (OR = 0.70, 95% CI = 0.50-0.98 for GG versus AA). We also observed a similar decrease (OR = 0.47, 95% CI = 0.23-0.95 for GG versus AA) in Caucasian samples. Variant -1195A/G in the promoter PTGS2 may protect against the malignant progression of HCC. This significant association suggests that -1195A/G could be used as a biomarker of HCC.

Human hepatic stellate cells are not permissive for hepatitis C virus entry and replication

BACKGROUND

Chronic HCV infection is associated with the development of hepatic fibrosis. The direct role of HCV in the fibrogenic process is unknown. Specifically, whether HCV is able to infect hepatic stellate cells (HSCs) is debated.

OBJECTIVE

To assess whether human HSCs are susceptible to HCV infection.

DESIGN

We combined a set of original HCV models, including the infectious genotype 2a JFH1 model (HCVcc), retroviral pseudoparticles expressing the folded HCV genotype 1b envelope glycoproteins (HCVpp) and a subgenomic genotype 1b HCV replicon, and two relevant cellular models, primary human HSCs from different patients and the LX-2 cell line, to assess whether HCV can infect/replicate in HSCs.

RESULTS

In contrast with the hepatocyte cell line Huh-7, neither infectious HCVcc nor HCVpp infected primary human HSCs or LX-2 cells. The cellular expression of host cellular factors required for HCV entry was high in Huh-7 cells but low in HSCs and LX-2 cells, with the exception of CD81. Finally, replication of a genotype 2a full-length RNA genome and a genotype 1b subgenomic replicon was impaired in primary human HSCs and LX-2 cells, which expressed low levels of cellular factors known to play a key role in the HCV life-cycle, suggesting that human HSCs are not permissive for HCV replication.

CONCLUSIONS

Human HSCs are refractory to HCV infection. Both HCV entry and replication are deficient in these cells, regardless of the HCV genotype and origin of the cells. Thus, HCV infection of HSCs does not play a role in liver fibrosis. These results do not rule out a direct role of HCV infection of hepatocytes in the fibrogenic process.

Hepatitis C Virus Nonstructural 3/4A Protein Dampens Inflammation and Contributes to Slow Fibrosis Progression during Chronic Fibrosis In Vivo

HCV infection typically induces liver injury and inflammation, which appears to be responsible for the associated fibrogenesis. To date, the mechanism underlying the different rates of disease progression remains unclear. The aim of the study is to understand the possible role of the HCV non-structural (NS) 3/4A protein in the fibrosis progression. We used NS3/4A-expressing transgenic mice (NS3/4A-Tg) to accomplish the goals of the study. Different stages of liver fibrosis were induced in wild-type and NS3/4A-Tg mice by single carbon tetrachloride (acute) or multiple injections for 4 (intermediate) or 8 (chronic) weeks. Fibrotic parameters, inflammatory responses and hepatocyte turnover were extensively examined. Hepatic expression of HCV NS3/4A did not induce spontaneous liver damage. However, NS3/4A expression exerted contrasting effects during acute and chronic liver damage. During early fibrogenesis and intermediate fibrosis (4 weeks), NS3/4A-Tg mice exhibited enhanced liver damage whereas reduced fibrosis was observed in NS3/4A-Tg during chronic liver fibrosis (8 weeks). Furthermore, attenuated inflammation was observed in NS3/4A-Tg during chronic fibrosis with increase in M2 macrophages, hepatocyte proliferation, decreased hepatocyte apoptosis and decreased ductular reaction. In conclusion, during early fibrogenesis, HCV NS3/4A contributes to liver damage. While, during chronic liver fibrosis, NS3/4A dampens inflammation and induces hepatocyte regeneration thereby contributing to slow fibrosis progression to promote its survival or persistence.

MicroRNAs: Role in Hepatitis C Virus pathogenesis

Hepatitis C virus (HCV) is a global health burden with an estimated 170-200 million peoples chronically infected worldwide. HCV infection remains as an independent risk factor for chronic hepatitis, liver cirrhosis, hepatocellular carcinoma, and a major reason for liver transplantation. Discovery of direct acting antiviral (DAA) drugs have shown promising results with more than 90% success rate in clearing the HCV RNA in patients, although long-term consequences remain to be evaluated. microRNAs (miRNAs) are important players in establishment of HCV infection and target crucial host cellular factors needed for productive HCV replication and augmented cell growth. Altered expression of miRNAs is involved in the pathogenesis associated with HCV infection by controlling signaling pathways such as immune response, proliferation and apoptosis. miRNA is emerging as a means of communication between various cell types inside the liver. There is likely possibility of developing circulating miRNAs as biomarkers of disease progression and can also serve as diagnostic tool with potential of early therapeutic intervention in HCV associated end stage liver disease. This review focuses on recent studies highlighting the contribution of miRNAs in HCV life cycle and their coordinated regulation in HCV mediated liver disease progression.

Recurrent HCV after liver transplantation-mechanisms, assessment and therapy

Chronic HCV infection is the leading indication for liver transplantation. However, as a result of HCV recurrence, patient and graft survival after liver transplantation are inferior compared with other indications for transplantation. HCV recurrence after liver transplantation is associated with considerable mortality and morbidity. The development of HCV-related fibrosis is accelerated after liver transplantation, which is influenced by a combination of factors related to the virus, donor, recipient, surgery and immunosuppression. Successful antiviral therapy is the only treatment that can attenuate fibrosis. The advent of direct-acting antiviral agents (DAAs) has changed the therapeutic landscape for the treatment of patients with HCV. DAAs have improved tolerability, and can potentially be used without PEG-IFN for a shorter time than previous therapies, which should result in better outcomes. In this Review, we describe the important risk factors that influence HCV recurrence after liver transplantation, highlighting the mechanisms of fibrosis and the integral role of hepatic stellate cells. Indirect and direct assessment of fibrosis, in addition to new antiviral therapies, are also discussed.

Hepatitis C virus-associated cancer

Hepatitis C virus (HCV) is one of the major etiologic agents of liver cancer. HCV is an RNA virus that, unlike hepatitis B virus, is unable to integrate into the host genome. Through complex interactions between viral and host proteins that induce host responses and promote inflammation, fibrosis, and ultimately cirrhosis, HCV infection can result in the development of hepatocellular carcinoma (HCC). The HCV oncogenic process involves genetic and epigenetic alterations and oncogenic effects mediated by viral proteins in the activation of cellular oncogenes, inactivation of tumor-suppressor genes, and dysregulation of multiple signal-transduction pathways. Advances in genetics and gene expression profiling have enhanced our current understanding of the pathways involved in HCV-associated liver cancer development. In this review, we summarize the current understanding of mechanisms of hepatocarcinogenesis induced by HCV infection.

Treatment options in patients with decompensated cirrhosis, pre- and post-transplantation

Interferon-based treatments have a poor safety profile and limited efficacy in patients with advanced liver disease and in patients with hepatitis C (HCV) recurrence after liver transplantation (LT). Despite the recent approval of the first interferon-free regimen, which will be followed by several other interferon-free combinations in 2014 and 2015, data in patients with advanced cirrhosis and hepatitis C after LT are still limited. One study has already proven the concept that graft HCV infection can be prevented in a significant proportion of patients by treating them with sofosbuvir and ribavirin while awaiting LT. Two interferon-free regimens have also demonstrated a high efficacy in patients with hepatitis C recurrence after transplantation. Before these treatment strategies can be implemented in clinical practice, a few issues need to be addressed: (1) safety and efficacy of new antivirals in patients with decompensated cirrhosis, (2) the impact of viral clearance on liver function, (3) the potential consequences of virological failure (and the selection of multi-drug resistant HCV strains) in patients with decompensated cirrhosis or with severe hepatitis C recurrence after LT, and (4) drug-drug interactions (DDI) profiles. Finally, in the transplant setting it is also relevant to learn which strategy is most cost-effective in minimizing the negative impact of hepatitis C: preventing graft infection by treating patients before transplantation or treating hepatitis C recurrence after LT.

Inhibition of tyrosine kinase receptor Tie2 reverts HCV-induced hepatic stellate cell activation

Background

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease (CLD) and is frequently linked to intrahepatic microvascular disorders. Activation of hepatic stellate cells (HSC) is a central event in liver damage, due to their contribution to hepatic renewal and to the development of fibrosis and hepatocarcinoma. During the progression of CLDs, HSC attempt to restore injured tissue by stimulating repair processes, such as fibrosis and angiogenesis. Because HSC express the key vascular receptor Tie2, among other angiogenic receptors and mediators, we analyzed its involvement in the development of CLD.

Methods

Tie2 expression was monitored in HSC cultures that were exposed to media from HCV-expressing cells (replicons). The effects of Tie2 blockade on HSC activation by either neutralizing antibody or specific signaling inhibitors were also examined.

Results

Media from HCV-replicons enhanced HSC activation and invasion and upregulated Tie2 expression. Notably, the blockade of Tie2 receptor (by a specific neutralizing antibody) or signaling (by selective AKT and MAPK inhibitors) significantly reduced alpha-smooth muscle actin (α-SMA) expression and the invasive potential of HCV-conditioned HSC.

Conclusions

These findings ascribe a novel profibrogenic function to Tie2 receptor in the progression of chronic hepatitis C, highlighting the significance of its dysregulation in the evolution of CLDs and its potential as a novel therapeutic target.

Prediction of fibrosis progression in chronic viral hepatitis

Prediction of liver fibrosis progression has a key role in the management of chronic viral hepatitis, as it will be translated into the future risk of cirrhosis and its various complications including hepatocellular carcinoma. Both hepatitis B and C viruses mainly lead to fibrogenesis induced by chronic inflammation and a continuous wound healing response. At the same time direct and indirect profibrogenic responses are also elicited by the viral infection. There are a handful of well-established risk factors for fibrosis progression including older age, male gender, alcohol use, high viral load and co-infection with other viruses. Metabolic syndrome is an evolving risk factor of fibrosis progression. The new notion of regression of advanced fibrosis or even cirrhosis is now strongly supported various clinical studies. Even liver biopsy retains its important role in the assessment of fibrosis progression, various non-invasive assessments have been adopted widely because of their non-invasiveness, which facilitates serial applications in large cohorts of subjects. Transient elastography is one of the most validated tools which has both diagnostic and prognostic role. As there is no single perfect test for liver fibrosis assessment, algorithms combining the most validated noninvasive methods should be considered as initial screening tools.

GIV/Girdin is a central hub for profibrogenic signalling networks during liver fibrosis

Progressive liver fibrosis is characterized by the deposition of collagen by activated hepatic stellate cells (HSCs). Activation of HSCs is a multiple receptor-driven process in which profibrotic signals are enhanced, and anti-fibrotic pathways are suppressed. Here we report the discovery of a novel signaling platform comprised of G protein subunit, Gαi and GIV, its guanine exchange factor (GEF), which serves as a central hub within the fibrogenic signalling network initiated by diverse classes of receptors. GIV is expressed in the liver after fibrogenic injury and is required for HSC activation. Once expressed, GIV enhances the profibrotic (PI3K-Akt-FoxO1 and TGFβ-SMAD) and inhibits the anti-fibrotic (cAMP-PKA-pCREB) pathways to skew the signalling network in favor of fibrosis, all via activation of Gαi. We also provide evidence that GIV may serve as a biomarker for progression of fibrosis after liver injury and a therapeutic target for arresting and/or reversing HSC activation during liver fibrosis.

Nrf2 ameliorates diabetic nephropathy progression by transcriptional repression of TGFβ1 through interactions with c-Jun and SP1

Diabetic nephropathy (DN) is one of the major complications in diabetes patients. Reactive oxygen species (ROS) play key roles in DN progression. As a primary transcription factor, Nrf2 controls the antioxidant response to maintain cellular redox homeostasis. Herein we systemically examined the role of Nrf2 in DN progression and its regulatory mechanism in a mouse model bearing type II diabetes and in cultured human renal mesangial cells (HRMCs). We found that Nrf2 could ameliorate DN progression by transcriptional repression of TGFβ1 in vivo and in vitro. Moreover, Nrf2 bound to the specific region in TGFβ1 promoter by interactions with transcription factors c-Jun and SP1. Significant abolishment of Nrf2-mediated TGFβ1 transcriptional repression could be accomplished by knockdown of either c-Jun or SP1, and site-directed mutagenesis of c-Jun and SP1 binding sites in the TGFβ1 promoter specific region. Moreover, after interacting with c-Jun and SP1, Nrf2 inhibited c-Jun and SP1 activations, and thus reversed c-Jun- and SP1-promoted TGFβ1 transcription. In all, Nrf2 could slow down DN progression by repression of TGFβ1 in a c-Jun and SP1-dependent way. Our findings may provide novel clues for DN preventions and interventions in clinic.

Pathogenesis of liver cirrhosis

Liver cirrhosis is the final pathological result of various chronic liver diseases, and fibrosis is the precursor of cirrhosis. Many types of cells, cytokines and miRNAs are involved in the initiation and progression of liver fibrosis and cirrhosis. Activation of hepatic stellate cells (HSCs) is a pivotal event in fibrosis. Defenestration and capillarization of liver sinusoidal endothelial cells are major contributing factors to hepatic dysfunction in liver cirrhosis. Activated Kupffer cells destroy hepatocytes and stimulate the activation of HSCs. Repeated cycles of apoptosis and regeneration of hepatocytes contribute to pathogenesis of cirrhosis. At the molecular level, many cytokines are involved in mediation of signaling pathways that regulate activation of HSCs and fibrogenesis. Recently, miRNAs as a post-transcriptional regulator have been found to play a key role in fibrosis and cirrhosis. Robust animal models of liver fibrosis and cirrhosis, as well as the recently identified critical cellular and molecular factors involved in the development of liver fibrosis and cirrhosis will facilitate the development of more effective therapeutic approaches for these conditions.

A Chinese herbal medicine, jia-wei-xiao-yao-san, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

Jia-wei-xiao-yao-san (JWXYS) is a traditional Chinese herbal medicine that is widely used to treat neuropsychological disorders. Only a few of the hepatoprotective effects of JWXYS have been studied. The aim of this study was to investigate the hepatoprotective effects of JWXYS on dimethylnitrosamine- (DMN-) induced chronic hepatitis and hepatic fibrosis in rats and to clarify the mechanism through which JWXYS exerts these effects. After the rats were treated with DMN for 3 weeks, serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) levels were significantly elevated, whereas the albumin level decreased. Although DMN was continually administered, after the 3 doses of JWXYS were orally administered, the SGOT and SGPT levels significantly decreased and the albumin level was significantly elevated. In addition, JWXYS treatment prevented liver fibrosis induced by DMN. JWXYS exhibited superoxide-dismutase-like activity and dose-dependently inhibited DMN-induced lipid peroxidation and xanthine oxidase activity in the liver of rats. Our findings suggest that JWXYS exerts antifibrotic effects against DMN-induced chronic hepatic injury. The possible mechanism is at least partially attributable to the ability of JWXYS to inhibit reactive-oxygen-species-induced membrane lipid peroxidation.

El-Aziz LF, Abdel kawy HS, AbdEl-Samad AA, El-Kharashi OA. Hepatoprotective effects of early pentoxifylline administration on hepatic injury induced by concanavalin A in rat

Tumor necrosis factor alpha (TNF-α) plays an important role in the pathogensis of hepatitis C virus (HCV) infection induced liver injury. This study aimed to evaluate the effects of TNF-α inhibition with pentoxifylline (PTX) on concanavalin A (Con A)-induced hepatic injury in rats. The rats were distributed among 3 groups: (i) control group (1 mL saline·week–1 by intravenous injection (i.v.)); (ii) Con A treatment group (20 mg Con A·(kg body mass)–1·week–1, i.v.), and (iii) rats treated with Con A and with PTX (200 mg PTX·(kg body mass)–1·day–1, per oral) group. Blood samples and livers were collected at the end of weeks 1, 2, 4, and 8 of Con A treatment. Portal pressure (PP) was measured at the end of week 8. The administration of PTX was found to confer significant protection against the injurious effects of Con A on the liver, by reducing serum levels of aspartate aminotransferase, alanine aminotransferase, hepatic TNF-α, and malondialdehyde. Histopathological examination revealed that treatment with PTX significantly suppressed early inflammation, reduced alpha smooth muscle actin, and the apoptosis of hepatocytes induced by Con A. Moreover, PTX significantly (P < 0.05) reduced PP, and quantitative analyses of the area of fibrosis induced by treatment with Con A showed a significant reduction at the end of week 8. We conclude that rats treated with PTX revealed a more or less normal hepatocyte architecture as well as marked improvement in fibrosis and PP.

Degradation of AIMP1/p43 induced by hepatitis C virus E2 leads to upregulation of TGF-β signaling and increase in surface expression of gp96

Hepatitis C virus (HCV) causes chronic hepatitis leading to liver fibrosis and autoimmune diseases. AIMP1/p43 is a multifunctional protein initially known as a cofactor of aminoacyl tRNA synthetase complex. Its function includes negative regulation of TGF-β signaling and suppression of Lupus-like autoimmune disease by inhibition of surface expression of gp96. HCV E2 was shown to directly interact with AIMP1/p43 by GST pulldown assay and coimmunoprecipitation. Their subcellular colocalization was observed in an immunofluorescence confocal microscopy. We showed that HCV E2 led to degradation of AIMP1/p43 in two ways. First, in the presence of HCV E2, endogenous AIMP1/p43 was shown to be degraded in an ubiquitin-dependent proteasome pathway. Second, grp78, an ER chaperone, was shown to interact with and stabilize AIMP1/p43. And HCV E2 inhibited this interaction leading to reduction of cellular AIMP1/p43. The degradation of AIMP1/p43 by HCV E2 resulted in increase of TGF-β signaling and cell surface expression of gp96. Thus we suggest that these are novel mechanisms responsible for liver fibrosis and autoimmune diseases caused by HCV.