Expression of the CXCR3 ligand I-TAC by hepatocytes in chronic hepatitis C and its correlation with hepatic inflammation

The Role of CXCL11 and its Receptors in Cancer: Prospective but Challenging Clinical Targets

Chemokine ligand 11 is a member of the CXC chemokine family and exerts its biological function mainly through binding to CXCR3 and CXCR7. The CXCL11 gene is ubiquitously overexpressed in various human malignant tumors; however, its specific mechanisms vary among different cancer types. Recent studies have found that CXCL11 is involved in the activation of multiple oncogenic signaling pathways and is closely related to tumorigenesis, progression, chemotherapy tolerance, immunotherapy efficacy, and poor prognosis. Depending on the specific expression of its receptor subtype, CXCL11 also has a complex 2-fold role in tumours; therefore, directly targeting the structure-function of CXCL11 and its receptors may be a challenging task. In this review, we summarize the biological functions of CXCL11 and its receptors and their roles in various types of malignant tumors and point out the directions for clinical applications.

Fueling HCC Dynamics: Interplay Between Tumor Microenvironment and Tumor Initiating Cells

Liver cancer (hepatocellular carcinoma) is a common cancer worldwide. It is an aggressive cancer, with high rates of tumor relapse and metastasis, high chemoresistance, and poor prognosis. Liver tumor-initiating cells (LTICs) are a distinctive subset of liver cancer cells with self-renewal and differentiation capacities that contribute to intratumoral heterogeneity, tumor recurrence, metastasis, and chemo-drug resistance. LTICs, marked by different TIC markers, have high plasticity and use diverse signaling pathways to promote tumorigenesis and tumor progression. LTICs are nurtured in the tumor microenvironment (TME), where noncellular and cellular components participate to build an immunosuppressive and tumor-promoting niche. As a result, the TME has emerged as a promising anticancer therapeutic target, as exemplified by some successful applications of tumor immunotherapy. In this review, we discuss the plasticity of LTICs in terms of cellular differentiation, epithelial-mesenchymal transition, and cellular metabolism. We also discuss the various components of the TME, including its noncellular and cellular components. Thereafter, we discuss the mutual interactions between TME and LTICs, including recently reported molecular mechanisms. Lastly, we summarize and describe new ideas concerning novel approaches and strategies for liver cancer therapy.

IFNβ-Induced CXCL10 Chemokine Expression Is Regulated by Pellino3 Ligase in Monocytes and Macrophages

IFN-I is the key regulatory component activating and modulating the response of innate and adaptive immune system to bacterial as well as viral pathogens. IFN-I promotes the expression of IFN-induced genes (ISG) and, consequently, the production of chemokines, e.g., CXCL10. Those chemokines control migration and localization of immune cells in tissues, and, thus, are critical to the function of the innate immune system during infection. Consequently, the regulation of IFN-I signaling is essential for the proper induction of an immune response. Our previous study has shown that E3 ubiquitin ligase Pellino3 positively regulates IFNβ expression and secretion. Herein, we examined the role of Pellino3 ligase in regulating CXCL10 expression in response to IFNβ stimulation. Our experiments were carried out on murine macrophage cell line (BMDM) and human monocytes cell line (THP-1) using IFNβ as a IFNAR ligand. We demonstrate that Pellino3 is important for IFNβ-induced phosphorylation and nuclear translocation of STAT1/STAT2/IRF9 complex which interacts with CXCL10 promoter and enhances its expression. In this study, we characterize a novel molecular mechanism allowing Pellino3-dependent modulation of the IFNβ-induced response in BMDM and THP-1 cell lines.

CXCL10 Chemokine: A Critical Player in RNA and DNA Viral Infections

Chemokines constitute a group of small, secreted proteins that regulate leukocyte migration and contribute to their activation. Chemokines are crucial inflammatory mediators that play a key role in managing viral infections, during which the profile of chemokine expression helps shape the immune response and regulate viral clearance, improving clinical outcome. In particular, the chemokine ligand CXCL10 and its receptor CXCR3 were explored in a plethora of RNA and DNA viral infections. In this review, we highlight the expression profile and role of the CXCL10/CXCR3 axis in the host defense against a variety of RNA and DNA viral infections. We also discuss the interactions among viruses and host cells that trigger CXCL10 expression, as well as the signaling cascades induced in CXCR3 positive cells.

Mechanism of cancer stemness maintenance in human liver cancer

Primary liver cancer mainly includes the following four types: hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), hepatoblastoma (HB), and combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CCA). Recent studies have indicated that there are differences in cancer stem cell (CSC) properties among different types of liver cancer. Liver cancer stem cells (LCSCs), also called liver tumor-initiating cells, have been viewed as drivers of tumor initiation and metastasis. Many mechanisms and factors, such as mitophagy, mitochondrial dynamics, epigenetic modifications, the tumor microenvironment, and tumor plasticity, are involved in the regulation of cancer stemness in liver cancer. In this review, we analyze cancer stemness in different liver cancer types. Moreover, we further evaluate the mechanism of cancer stemness maintenance of LCSCs and discuss promising treatments for eradicating LCSCs.

Prediction of hepatic inflammation in chronic hepatitis B patients with a random forest-backward feature elimination algorithm

BACKGROUND

Persistent liver inflammatory damage is the main risk factor for developing liver fibrosis, cirrhosis, and even hepatocellular carcinoma in chronic hepatitis B (CHB) patients. Thus, accurate prediction of the degree of liver inflammation is a high priority and a growing medical need.

AIM

To build an effective and robust non-invasive model for predicting hepatitis B-related hepatic inflammation.

METHODS

A total of 650 treatment-naïve CHB (402 HBeAg-positive and 248 HBeAg-negative) patients who underwent liver biopsy were enrolled in this study. Histological inflammation grading was assessed by the Ishak scoring system. Serum quantitative hepatitis B core antibody (qAnti-HBc) levels and 21 immune-related inflammatory factors were measured quantitatively using a chemiluminescent microparticle immunoassay. A backward feature elimination (BFE) algorithm utilizing random forest (RF) was used to select optional features and construct a combined model. The diagnostic abilities of the model or variables were evaluated based on the estimated area under the receiver operating characteristics curve (AUROC) and compared using the DeLong test.

RESULTS

Four features were selected to predict moderate-to-severe inflammation in CHB patients using the RF-BFE method. These predictive features included qAnti-HBc, ALT, AST, and CXCL11. Spearman’s correlation analysis indicated that serum qAnti-HBc, ALT, AST, and CXCL11 levels were positively correlated with the histology activity index (HAI) score. These selected features were incorporated into the model to establish a novel model named I-3A index. The AUROC [0.822; 95% confidence interval (CI): 0.790-0.851] of the I-3A index was significantly increased compared with qAnti-HBc alone (0.760, 95%CI: 0.724-0.792, P < 0.0001) in all CHB patients. The use of an I-3A index cutoff value of 0.41 produced a sensitivity of 69.17%, specificity of 81.44%, and accuracy of 73.8%. Additionally, the I-3A index showed significantly improved diagnostic performance for predicting moderate-to-severe inflammation in HBeAg-positive and HBeAg-negative CHB patients (0.829, 95%CI: 0.789-0.865 and 0.810, 95%CI: 0.755-0.857, respectively).

CONCLUSION

The selected features of the I-3A index constructed using the RF-BFE algorithm can effectively predict moderate-to-severe liver inflammation in CHB patients.

Cancer-associated fibroblast-derived CXCL11 modulates hepatocellular carcinoma cell migration and tumor metastasis through the circUBAP2/miR-4756/IFIT1/3 axis

Cancer-associated fibroblasts (CAFs) are commonly acquired activated extracellular matrix (ECM)-producing myofibroblasts, a phenotypes with multiple roles in hepatic fibrogenesis and carcinogenesis via crosstalk with cohabitating stromal/cancer cells. Here, we discovered a mechanism whereby CAF-derived cytokines enhance hepatocellular carcinoma (HCC) progression and metastasis by activating the circRNA-miRNA-mRNA axis in tumor cells. CAFs secreted significantly higher levels of CXCL11 than normal fibroblasts (NFs), and CXCL11 also had comparatively higher expressions in HCC tissues, particularly in metastatic tissues, than para-carcinoma tissues. Both CAF-derived and experimentally introduced CXCL11 promoted HCC cell migration. Likewise, CAFs promoted tumor migration in orthotopic models, as shown by an increased number of tumor nodules, whereas CXCL11 silencing triggered a decrease of it. CXCL11 stimulation upregulated circUBAP2 expression, which was significantly higher in HCC tissues than para-carcinoma tissues. Silencing circUBAP2 reversed the effects of CXCL11 on the expression of IL-1β/IL-17 and HCC cell migration. Further downstream, the IFIT1 and IFIT3 levels were significantly upregulated in HCC cells upon CXCL11 stimulation, but downregulated upon circUBAP2 silencing. IFIT1 or IFIT3 silencing reduced the expression of IL-17 and IL-1β, and attenuated the migration capability of HCC cells. Herein, circUBAP2 counteracted miR-4756-mediated inhibition on IFIT1/3 via sponging miR-4756. miR-4756 inhibition reversed the effects induced by circUBAP2 silencing on the IL-17 and IL-1β levels and HCC cell migration. In orthotopic models, miR-4756 inhibition also reversed the effects on metastatic progression induced by silencing circUBAP2.

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

Specific Commensal Bacterium Critically Regulates Gut Microbiota Osteoimmunomodulatory Actions During Normal Postpubertal Skeletal Growth and Maturation

The commensal gut microbiota critically regulates immunomodulatory processes that influence normal skeletal growth and maturation. However, the influence of specific microbes on commensal gut microbiota osteoimmunoregulatory actions is unknown. We have shown previously that the commensal gut microbiota enhances T_H17/IL17A immune response effects in marrow and liver that have procatabolic/antianabolic actions in the skeleton. Segmented filamentous bacteria (SFB), a specific commensal gut bacterium within phylum Firmicutes, potently induces T_H17/IL17A‐mediated immunity. The study purpose was to delineate the influence of SFB on commensal gut microbiota immunomodulatory actions regulating normal postpubertal skeletal development. Two murine models were utilized: SFB‐monoassociated mice versus germ‐free (GF) mice and specific‐pathogen‐free (SPF) mice +/− SFB. SFB colonization was validated by 16S rDNA analysis, and SFB‐induced T_H17/IL17A immunity was confirmed by upregulation of Il17a in ileum and IL17A in serum. SFB‐colonized mice had an osteopenic trabecular bone phenotype, which was attributed to SFB actions suppressing osteoblastogenesis and enhancing osteoclastogenesis. Intriguingly, SFB‐colonized mice had increased expression of proinflammatory chemokines and acute‐phase reactants in the liver. Lipocalin‐2 (LCN2), an acute‐phase reactant and antimicrobial peptide, was substantially elevated in the liver and serum of SFB‐colonized mice, which supports the notion that SFB regulation of commensal gut microbiota osteoimmunomodulatory actions are mediated in part through a gut–liver–bone axis. Proinflammatory T_H17 and T_H1 cells were increased in liver‐draining lymph nodes of SFB‐colonized mice, which further substantiates that SFB osteoimmune‐response effects may be mediated through the liver. SFB‐induction of Il17a in the gut and Lcn2 in the liver resulted in increased circulating levels of IL17A and LCN2. Recognizing that IL17A and LCN2 support osteoclastogenesis/suppress osteoblastogenesis, SFB actions impairing postpubertal skeletal development appear to be mediated through immunomodulatory effects in both the gut and liver. This research reveals that specific microbes critically impact commensal gut microbiota immunomodulatory actions regulating normal postpubertal skeletal growth and maturation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Role of chemokines in Parkinson's disease

Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder with an increasing incidence year by year, particularly as the population ages. The most common neuropathologic manifestation in patients with Parkinson's disease is dopamine neurons degeneration and loss in substantia nigra of middle brain. The main neurochemistry problem is the lack of the neurotransmitter dopamine. Clinically, PD patients may also have higher levels of glutamate, gamma-aminobutyric acid, acetylcholine and other neurotransmitters. At present, many data have shown that some chemokines are involved in regulating the release and transmission of neurotransmitters, and the growth and development of related neurons. In recent years, most of the studies relative to PD is based on immune and inflammatory mechanisms, and chemokines is also the focus on this mechanism. Chemokines are a class of cytokines that have definite chemotaxis effects on the different target cells. They might be involved in the pathogenesis of PD by inducing neuronal apoptosis and microglia activation. Clinical data has shown that the levels of chemokines in plasma and cerebrospinal fluid of PD patients have corresponding changes compared with the healthy persons. This review summarizes recent studies on chemokines and their receptors in Parkinson's disease: (i) to explore the role of chemokines in Parkinson's disease; (ii) to provide new indicators for clinical diagnosis of PD; (iii) to provide new targets for drug research and development in the treatment of Parkinson's disease.

Circulating levels of CXCL11 and CXCL12 are biomarkers of cirrhosis in patients with chronic hepatitis C infection

BACKGROUND & AIMS

The chemokines CXCL10 (interferon ϒ-inducible protein 10 [IP-10]), CXCL11 (Human interferon inducible T cell alpha chemokine [I-TAC]), and CXCL12 (stromal cell derived factor 1 [SDF-1]) contribute to cell recruitment, migration, activation, and homing in liver diseases and their serum levels have been shown to be associated with the degree of liver inflammation or fibrosis in various etiologies. However, the data may be contradictory or insufficient, particularly for CXCL12, in the field of chronic HCV infection. Here, we aimed to provide evidence for these chemokines as biomarkers for chronic HCV infection.

METHODS

We analyzed the serum concentration of the three chemokines in healthy donors (n = 39) and patients (n = 87) with chronic HCV infection. Chemokine serum levels were compared to the stage of liver inflammation and fibrosis obtained from liver biopsies.

RESULTS

Serum CXCL10 and CXCL11 levels were higher at advanced stages of liver inflammation than at earlier stages, but the results were only of medium significance. Both serum CXCL11 and CXCL12 levels were significantly higher in cirrhotic patients than those with low or medium stages of fibrosis. The AUROCs were 0.8167 and 0.8574, respectively, for the diagnosis of cirrhotic patients.

CONCLUSION

These data provide evidence for the value of CXCL10, CXCL11, and CXCL12 as biomarkers of liver inflammation and fibrosis during chronic HCV infection. Serum CXCL10 and CXCL11 levels were associated with liver inflammation, but the level of significance was insufficient. However, serum CXCL11 and CXCL12 levels were elevated in cirrhotic patients, showing equivalent diagnostic accuracy as the existing established single serum fibrosis markers or algorithms.

CXCL11 promotes self-renewal and tumorigenicity of α2δ1+ liver tumor-initiating cells through CXCR3/ERK1/2 signaling

Tumor-initiating cells (TICs), which are responsible for sustaining tumor growth and recurrence, rely on several regulatory factors. However, the mechanism of inflammation-related molecules in the acquisition and maintenance of TIC properties in hepatocellular carcinoma (HCC) remains elusive. We previously demonstrated that the voltage-gated calcium channel α2δ1 subunit is a functional surface marker of HCC TICs. Here, we found that the expression of an inflammation-related molecule C-X-C motif chemokine 11 (CXCL11) was significantly upregulated in α2δ1⁺ HCC TICs and that CXCL11 induced the expression of stem cell-related genes, such as BMI1, NANOG, MDR1, ABCG2, and CACNA2D1. Furthermore, CXCL11 could promote the acquisition and maintenance of self-renewal, tumorigenic, and chemoresistance properties of α2δ1⁺ HCC TICs by activating the extracellular signal-regulated kinase (ERK1/2) through its affinity receptor CXCR3. Collectively, our results suggest that CXCL11 may positively regulate the stemness of α2δ1⁺ HCC TICs via ERK1/2 activation through an autocrine signaling pathway.

COMMD7 activates CXCL10 production by regulating NF-κB and the production of reactive oxygen species

While >80% of the incidence occurs in sub‑Saharan Africa and East Asia, cases of hepatocellular carcinoma (HCC) have been rapidly increasing in Western countries. Despite its global importance, HCC is relatively under‑researched compared with other lethal cancer types, which is possibly due to the high complexity and heterogeneity of HCC. It has been reported previously that COMM domain‑containing protein 7 (COMMD7) is upregulated in HCC and promotes HCC cell proliferation by triggering C‑X‑C motif chemokine 10 (CXCL10) production. However, the value of targeting CXCL10 signal transduction in treating COMMD7‑positive tumors, or the molecular mechanisms underlying COMMD7‑mediated CXCL10 expression, has not been completely addressed. In the present study, it was demonstrated that disruption of the CXCL10/C‑X‑C chemokine receptor type 3 axis reduces COMMD7‑mediated HCC cell proliferation. Furthermore, COMMD7 modulates CXCL10 production by activating nuclear factor (NF)‑κB. Additionally, it was demonstrated that intracellular reactive oxygen species (ROS) are required for NF‑κB activation and CXCL10 production. In conclusion, COMMD7 activates CXCL10 production by regulating NF‑κB and the production of ROS. The present study highlighted the role of COMMD7 in the development of HCC, and provides novel options for anticancer drug design.

Proliferative capacity exhibited by human liver-resident CD49a+CD25+ NK cells

The recruitment and retention of Natural Killer (NK) cells in the liver are thought to play an important role during hepatotropic infections and liver cirrhosis. The aims of this study were to determine differences between liver-derived and peripheral blood-derived NK cells in the context of liver inflammation and cirrhosis. We conducted a prospective dual-center cross-sectional study in patients undergoing liver transplantation or tumor-free liver resections, in which both liver tissue and peripheral blood samples were obtained from each consenting study participants. Intrahepatic lymphocytes and PBMCs were stained, fixed and analyzed by flow cytometry. Our results showed that, within cirrhotic liver samples, intrahepatic NK cells were particularly enriched for CD49a+ NK cells when compared to tumor-free liver resection samples. CD49a+ liver-derived NK cells included populations of cells expressing CD25, CD34 and CXCR3. Moreover, CD49a+CD25+ liver-derived NK cells exhibited high proliferative capacity in vitro in response to low doses of IL-2. Our study identified a specific subset of CD49a+CD25+ NK cells in cirrhotic livers bearing functional features of proliferation.

CXCL10 is produced in hepatitis A virus-infected cells in an IRF3-dependent but IFN-independent manner

Acute hepatitis A caused by hepatitis A virus (HAV) infection is accompanied by severe liver injury in adult patients, and the liver injury is associated with the production of chemokines. Herein, we investigated the mechanism of how HAV infection induces the production of CXCR3 and CCR5 chemokines, such as CXCL10, CCL4 and CCL5. The production of CXCL10, CCL4 and CCL5 was markedly increased by HAV (HM-175/18f) infection in the culture of primary human hepatocytes and HepG2 cells. In particular, CXCL10 was produced in HAV-infected cells, not in neighboring uninfected cells. Moreover, these chemokines were significantly increased in the sera of acute hepatitis A patients. The production of IFN-λs was also robustly induced by HAV infection, and the blocking of secreted IFN-λs partially abrogated the production of CCL4 and CCL5 in HAV-infected cells. However, CXCL10 production was not decreased by the blocking of IFN-λs. Instead, CXCL10 production was reduced by silencing the expression of RIG-I-like receptor (RLR) signal molecules, such as mitochondrial antiviral signaling protein and interferon regulatory factor 3, in HAV-infected cells. In conclusion, HAV infection strongly induces the production of helper 1 T cell-associated chemokines, particularly CXCL10 via RLR signaling, even without secreted IFNs.

Predictive Value of Serum IFN-γ inducible Protein-10 and IFN-γ/IL-4 Ratio for Liver Fibrosis Progression in CHB Patients

Noninvasive serum markers for assessment of liver fibrosis in chronic hepatitis B (CHB) patients have not been well-studied. The present study was to evaluate the predictive value of serum interferon gamma-inducible protein-10 (IP-10/CXCL10) and the interferon (IFN)-γ/interleukin (IL)-4 ratio for liver fibrosis progression in CHB patients. A total of 180 CHB patients were categorized into four groups: no fibrosis, mild fibrosis, moderate fibrosis, and severe fibrosis. Serum and intrahepatic levels of IP-10, IFN-γ, and IL-4 were examined, from which the IFN-γ/IL-4 ratio was calculated. We found that the serum IP-10 levels were positively correlated with the severity of liver fibrosis, whereas the IFN-γ/IL-4 ratio was negatively associated with the progression of hepatic fibrosis. Multivariate logistic regression analysis revealed that the serum IP-10 was an independent predictor for significant fibrosis. For predicting significant fibrosis, the IP-10 cut-off value of 300 ng/mL had a sensitivity of 92.7% and a specificity of 68.6%. When the IP-10 level was combined with the IFN-γ/IL-4 ratio, the specificity and positive predictive value were 93.8% and 94.6%, respectively; thus, the discriminatory ability was much improved. In conclusion, the serum IP-10 level and the IFN-γ/IL-4 ratio have great potential to predict significant fibrosis among CHB patients.

Acute Liver Damage Associated with Innate Immune Activation in a Small Nonhuman Primate Model of Hepacivirus Infection

Despite its importance in shaping adaptive immune responses, viral clearance, and immune-based inflammation, tissue-specific innate immunity remains poorly characterized for hepatitis C virus (HCV) infection due to the lack of access to acutely infected tissues. In this study, we evaluated the impact of natural killer (NK) cells and myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells on control of virus replication and virus-induced pathology caused by another, more rapidly resolving hepacivirus, GB virus B (GBV-B), in infections of common marmosets. High plasma and liver viral loads and robust hepatitis characterized acute GBV-B infection, and while viremia was generally cleared by 2 to 3 months postinfection, hepatitis and liver fibrosis persisted after clearance. Coinciding with peak viral loads and liver pathology, the levels of NK cells, mDCs, and pDCs in the liver increased up to 3-fold. Although no obvious numerical changes in peripheral innate cells occurred, circulating NK cells exhibited increased perforin and Ki67 expression levels and increased surface expression of CXCR3. These data suggested that increased NK cell arming and proliferation as well as tissue trafficking may be associated with influx into the liver during acute infection. Indeed, NK cell frequencies in the liver positively correlated with plasma (R = 0.698; P = 0.015) and liver (R = 0.567; P = 0.057) viral loads. Finally, soluble factors associated with NK cells and DCs, including gamma interferon (IFN-γ) and RANTES, were increased in acute infection and also were associated with viral loads and hepatitis. Collectively, the findings showed that mobilization of local and circulating innate immune responses was linked to acute virus-induced hepatitis, and potentially to resolution of GBV-B infection, and our results may provide insight into similar mechanisms in HCV infection.

IMPORTANCE

Hepatitis C virus (HCV) infection has created a global health crisis, and despite new effective antivirals, it is still a leading cause of liver disease and death worldwide. Recent evidence suggests that innate immunity may be a potential therapeutic target for HCV, but it may also be a correlate of increased disease. Due to a lack of access to human tissues with acute HCV infection, in this study we evaluated the role of innate immunity in resolving infection with a hepacivirus, GBV-B, in common marmosets. Collectively, our data suggest that NK cell and DC mobilization in acute hepacivirus infection can dampen virus replication but also regulate acute and chronic liver damage. How these two opposing effects on the host may be modulated in future therapeutic and vaccine approaches warrants further study.

Up-regulation of Plasma Hexosylceramide (d18: 1/18: 1) Contributes to Genotype 2 Virus Replication in Chronic Hepatitis C: A 20-Year Cohort Study

The aim of the present study was to explore the relationship between plasma sphingolipids and hepatitis C virus (HCV) replication in chronic hepatitis C (CHC) patients.A cohort of 120 treatment-naïve CHC patients was included. Liver biopsies and the Scheuer scoring system were used to assess hepatic inflammatory activity. Blood biochemical indicators, HCV-RNA load, and immunological markers were also measured. Forty-four plasma sphingolipids were identified and quantified using high-performance liquid chromatography-tandem mass spectrometry.The hexosylceramide (HexCer) (d18:1/18:1) level was significantly different between patients with a low HCV load (<10 IU/mL) and a high HCV load (≥10 IU/mL), and it was positively correlated with the HCV-RNA load (r = 0.337, P = 0.001) in CHC patients. Additionally, the plasma HexCer (d18:1/18:1) level (odds ratio 1.302, 95% confidence interval 1.129-1.502) was an independent factor for a high HCV-RNA load. For patients with hepatic inflammation grade ≤2 or HCV genotype 2, HexCer (d18:1/18:1) was independently related to a high HCV-RNA load.Plasma HexCer (d18:1/18:1) might be involved in the high viral replication level in chronic HCV infection, especially for CHC patients with genotype 2.

Association of IL28B Genotypes and Baseline Serum Interferon-γ-Inducible- Protein-10 Levels with Treatment Response in Hepatitis C Virus Patients in China

BACKGROUND/AIMS

Several studies have demonstrated that serum interferon-γ-inducible-protein-10 (IP-10) levels at baseline and single nucleotide polymorphisms (SNPs) near the IL28B gene were associated with viral response and treatment outcomes. Our purpose was to assess the combination of pretreatment IP-10 levels with IL28B SNPs as predictors of treatment response to pegylated interferon α-2a plus ribavirin in patients infected with genotype 1 hepatitis C virus in China.

METHODS

Seventy-two patients with chronic hepatitis C without fibrosis/cirrhosis were enrolled in the study. The virologic parameters and baseline serum IP-10 levels were determined. IL-28B genotypes were determined by sequencing.

RESULTS

In this cohort, serum baseline IP-10 levels lower than 426.7 pg/mL could predict rapid virological response/ sustained virological response (SVR). Patients carrying favorable IL28B SNP genotypes had higher SVRs than did those carrying unfavorable variants (IL28B rs12979860, p=0.002; IL28B rs8099917, p=0.020). Combining both baseline IP- 10 and IL28B SNPs could improve the prediction of SVR in favorable allele carriers of IL28B, rs12979860 CC and rs8099917 TT. Serum baseline IP-10 levels and IL28B genotypes were independent predictors of SVR.

CONCLUSIONS

Our study shows that the combination of baseline serum IP-10 levels and the determination of IL28B SNPs increase the predictability of SVR rates in this cohort. (Gut Liver 2016;10446-455).

Comparative Analysis of Liver Injury-Associated Cytokines in Acute Hepatitis A and B

PURPOSE

Acute hepatitis A (AHA) and acute hepatitis B (AHB) are caused by an acute infection of the hepatitis A virus and the hepatitis B virus, respectively. In both AHA and AHB, liver injury is known to be mediated by immune cells and cytokines. In this study, we measured serum levels of various cytokines and T-cell cytotoxic proteins in patients with AHA or AHB to identify liver injury-associated cytokines.

MATERIALS AND METHODS

Forty-six patients with AHA, 16 patients with AHB, and 14 healthy adults were enrolled in the study. Serum levels of 17 cytokines and T-cell cytotoxic proteins were measured by enzyme-linked immunosorbent assays or cytometric bead arrays and analyzed for correlation with serum alanine aminotransferase (ALT) levels.

RESULTS

Interleukin (IL)-18, IL-8, CXCL9, and CXCL10 were significantly elevated in both AHA and AHB. IL-6, IL-22, granzyme B, and soluble Fas ligand (sFasL) were elevated in AHA but not in AHB. In both AHA and AHB, the serum level of CXCL10 significantly correlated with the peak ALT level. Additionally, the serum level of granzyme B in AHA and the serum level of sFasL in AHB correlated with the peak ALT level.

CONCLUSION

We identified cytokines and T-cell cytotoxic proteins associated with liver injury in AHA and AHB. These findings deepen the existing understanding of immunological mechanisms responsible for liver injury in acute viral hepatitis.

Chemokine receptor CXCR3 in turbot (Scophthalmus maximus): cloning, characterization and its responses to lipopolysaccharide

Chemokine (C-X-C motif) receptor 3, a member of the G protein-coupled receptors superfamily, regulates the responses of many immune responses. In this experiment, we cloned and characterized the cDNA of CXCR3 in Scophthalmus maximus (turbot). A 5'-UTR of 216-bp, a 259-bp 3'-UTR with a poly (A) tail and a 1089-bp CDS encoding 362 amino acids form the cDNA of CXCR3, which is 1564-bp long. Phylogenetic analyses indicated that turbot CXCR3 shared a high similarity with other CXCR3s and shared more similarity with CXCR5 than the other subfamilies of chemokines. The CXCR3 protein in turbot showed the highest similarity with the CXCR3b from rainbow trout (44.5%), which indicated that this CXCR3 gene/protein may be a CXCR3b isoform. Quantitative real-time PCR analysis showed that CXCR3 transcripts were constitutively expressed in all the tissues of the non-injected turbot used in this study, with the highest expression occurring in blood. Several immune-related tissues of fish, such as the spleen, head kidney, liver and blood, tissues, which were abundant of lymphocyte, were investigated in this study. CXCR3 gene was expressed at the highest level in blood than the other tested tissues. The injection experiment suggested that the CXCR3 expression level after LPS injection was significantly up-regulated in all immune-related tissues in turbot. These results improve our understanding of the functions of CXCR3 in the turbot immune response.

Chemokine (C-X-C motif) ligand 11 levels predict survival in cirrhotic patients with transjugular intrahepatic portosystemic shunt

BACKGROUND & AIMS

Chemokines, such as CXCR3-ligands, have been identified to play an important role during hepatic injury, inflammation and fibrosis. While CXCL9 is associated with survival in patients receiving transjugular intrahepatic portosystemic shunt (TIPS), the role of CXCL11 in severe portal hypertension remains unknown.

METHODS

CXCL11-levels were measured in 136 patients with liver diseases, and 63 healthy controls. In further 47 cirrhotic patients receiving TIPS, CXCL11 levels were measured in portal and hepatic veins at TIPS insertion by cytometric bead array. CXCL11-levels were measured in 23 patients in cubital vein and right atrium, whereas in 24 patients in portal and hepatic blood at an invasive reevaluation.

RESULTS

CXCL11-levels were increased with the severity of liver fibrosis. CXCL11-levels from portal, hepatic and cubital veins and right atrium showed a highly significant correlation among each other in these patients. Furthermore, levels of CXCL11 from the right atrium were significantly higher than those from cubital vein. Interestingly, patients with alcoholic cirrhosis had significantly lower CXCL11-levels, than other aetiologies of cirrhosis. After TIPS, CXCL11 levels correlated with the degree of portal pressure and patients with higher CXCL11-levels in portal and hepatic veins showed higher mortality. Multivariate analysis revealed hepatic CXCL11-levels before TIPS, creatinine and age as independent predictors for survival in TIPS patients, whereas MELD score and low portal CXCL11-levels after TIPS predicted long-term survival.

CONCLUSION

CXCL11 levels are mainly increased in patients with non-alcoholic cirrhosis and high portal pressure. Moreover, levels of CXCL11 might predict long-time survival of cirrhotic patients bearing TIPS.

High MIG (CXCL9) plasma levels favours response to peginterferon and ribavirin in HCV-infected patients regardless of DPP4 activity

BACKGROUND & AIMS

Sustained virological response (SVR) following peginterferon (pegIFN) and ribavirin (RBV) treatment in hepatitis C virus (HCV)-infected patients has been linked with the IL28B genotype and lower peripheral levels of the CXCR3-binding chemokine IP-10 (CXCL10). To further improve the understanding of these biomarkers we investigated plasma levels of the other CXCR3-binding chemokines and activity of the dipeptidyl peptidase IV (DPP4, CD26) protease, which cleaves IP-10, in relation to treatment response.

METHODS

African-American and Caucasian HCV genotype 1-infected patients (n = 401) were treated with pegIFN/RBV for 48 weeks (ViraHep-C cohort). Pretreatment plasma levels of MIG (CXCL9), I-TAC (CXCL11) and the type III interferon IL29 were investigated by Luminex and DPP4 activity by using a luciferase assay.

RESULTS

Patients achieving SVR had higher baseline MIG plasma levels and lower DPP4 activity than non-SVR patients. MIG was higher in Caucasians, IL28B CC (rs1297860) genotype carriers and patients with higher ALT levels. MIG correlated with IP-10 in SVR patients, but not in non-SVRs. A high DPP4 activity correlated with higher IP-10 levels, while DPP4 activity was not associated with MIG or I-TAC levels.

CONCLUSIONS

The associations of MIG with SVR status and IL28B genotype imply that higher MIG plasma levels could reflect a beneficial immunological state for response to pegIFN/RBV treatment. The correlation between MIG and IP-10 observed only in SVR patients may contribute to a better treatment response, whereas this MIG/IP-10 balance might be disrupted in non-SVR patients because of the increased DPP4 cleavage of IP-10 into a dysfunctional form.

Alanine aminotransferase, HCV RNA levels and pro-inflammatory and pro-fibrogenic cytokines/chemokines during acute hepatitis C virus infection

Background

This study assessed the association of alanine-aminotransferase (ALT) and hepatitis C virus (HCV) RNA levels with pro-inflammatory and pro-fibrogenic cytokines and chemokines during acute HCV infection to provide further insight into the potential HCV immunopathogenesis.

Methods

Participants in the ATAHC study, a prospective study of recent HCV infection, with detectable HCV RNA at the time of HCV detection were included. Plasma levels of 27 cytokines and chemokines were measured and their correlation with ALT and HCV RNA levels were assessed. Log₁₀ transformed cytokines and ALT values were used in the analysis.

Results

Among 117 individuals, the plasma levels of interferon-gamma inducible protein-10 (IP-10) and macrophage inflammatory protein-1beta (MIP-1β) were positively correlated with ALT levels (IP-10: r = 0.42, P < 0.001; MIP-1β: r = 0.29, P = 0.001) and HCV RNA levels (IP-10: rs = 0.44, P < 0.001; MIP-1β: rs = 0.43, P < 0.001). Using linear regression, after adjusting for sex, age, infection duration, symptomatic infection, HIV co-infection, interferon-lambda rs12979860 genotype, HCV genotype, and assay run, higher ALT levels (β = 0.20; 95 % CI: 0.07, 0.32; P = 0.002) and HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; β = 0.16; 95 % CI: 0.03, 0.28; P = 0.014) were independently associated with higher IP-10 levels. HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; β = 0.16; 95 % CI: 0.01, 0.31; P = 0.036) were associated with higher MIP-1β levels.

Conclusions

During acute HCV infection, high ALT and HCV RNA levels were associated with increased IP-10 levels, while high HCV RNA levels were also associated with increased MIP-1β levels. These data suggest that IP-10 and MIP-1β may have a role in HCV immuno-pathogenesis starting early in acute HCV infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0482-x) contains supplementary material, which is available to authorized users.

PRMT5-Mediated Methylation of NF-κB p65 at Arg174 Is Required for Endothelial CXCL11 Gene Induction in Response to TNF-α and IFN-γ Costimulation

Inflammatory agonists differentially activate gene expression of the chemokine family of proteins in endothelial cells (EC). TNF is a weak inducer of the chemokine CXCL11, while TNF and IFN-γ costimulation results in potent CXCL11 induction. The molecular mechanisms underlying TNF plus IFN-γ-mediated CXCL11 induction are not fully understood. We have previously reported that the protein arginine methyltransferase PRMT5 catalyzes symmetrical dimethylation of the NF-κB subunit p65 in EC at multiple arginine residues. Methylation of Arg30 and Arg35 on p65 is critical for TNF induction of CXCL10 in EC. Here we show that PRMT5-mediated methylation of p65 at Arg174 is required for induction of CXCL11 when EC are costimulated with TNF and IFN-γ. Knockdown of PRMT5 by RNAi reduced CXCL11 mRNA and protein levels in costimulated cells. Reconstitution of p65 Arg174Ala or Arg174Lys mutants into EC that were depleted of endogenous p65 blunted TNF plus IFN-γ-mediated CXCL11 induction. Mass spectrometric analyses showed that p65 Arg174 arginine methylation is enhanced by TNF plus IFN-γ costimulation, and is catalyzed by PRMT5. Chromatin immunoprecipitation assays (ChIP) demonstrated that PRMT5 is necessary for p65 association with the CXCL11 promoter in response to TNF plus IFN-γ. Further, reconstitution of p65 Arg174Lys mutant in EC abrogated this p65 association with the CXCL11 promoter. Finally, ChIP and Re-ChIP assays revealed that symmetrical dimethylarginine-containing proteins complexed with the CXCL11 promoter were diminished in p65 Arg174Lys-reconstituted EC stimulated with TNF and IFN-γ. In total, these results indicate that PRMT5-mediated p65 methylation at Arg174 is essential for TNF plus IFN-γ-mediated CXCL11 gene induction. We therefore suggest that the use of recently developed small molecule inhibitors of PRMT5 may present a therapeutic approach to moderating chronic inflammatory pathologies.

The Interferon-induced Transmembrane Proteins, IFITM1, IFITM2, and IFITM3 Inhibit Hepatitis C Virus Entry

The interferon-induced transmembrane (IFITM) family of proteins have recently been identified as important host effector molecules of the type I interferon response against viruses. IFITM1 has been identified as a potent antiviral effector against hepatitis C virus (HCV), whereas the related family members IFITM2 and IFITM3 have been described to have antiviral effects against a broad range of RNA viruses. Here, we demonstrate that IFITM2 and IFITM3 play an integral role in the interferon response against HCV and act at the level of late entry stages of HCV infection. We have established that in hepatocytes, IFITM2 and IFITM3 localize to the late and early endosomes, respectively, as well as the lysosome. Furthermore, we have demonstrated that S-palmitoylation of all three IFITM proteins is essential for anti-HCV activity, whereas the conserved tyrosine residue in the N-terminal domain of IFITM2 and IFITM3 plays a significant role in protein localization. However, this tyrosine was found to be dispensable for anti-HCV activity, with mutation of the tyrosine resulting in an IFITM1-like phenotype with the retention of anti-HCV activity and co-localization of IFITM2 and IFITM3 with CD81. In conclusion, we propose that the IFITM proteins act in a coordinated manner to restrict HCV infection by targeting the endocytosed HCV virion for lysosomal degradation and demonstrate that the actions of the IFITM proteins are indeed virus and cell-type specific.

Chemokines and their receptors play important roles in the development of hepatocellular carcinoma

The chemokine system consists of four different subclasses with over 50 chemokines and 19 receptors. Their functions in the immune system have been well elucidated and research during the last decades unveils their new roles in hepatocellular carcinoma (HCC). The chemokines and their receptors in the microenvironment influence the development of HCC by several aspects including: inflammation, effects on immune cells, angiogenesis, and direct effects on HCC cells. Regarding these aspects, pre-clinical research by targeting the chemokine system has yielded promising data, and these findings bring us new clues in the chemokine-based therapies for HCC.

Single nucleotide polymorphisms of CXCL9-11 chemokines are associated with liver fibrosis in HIV/HCV-coinfected patients

BACKGROUND

CXCR3A-associated chemokines (CXCL9-11) are implicated in the pathogenesis of hepatitis C virus (HCV) infection. We analyzed the association between CXCL9-11 polymorphisms and significant liver fibrosis in human immunodeficiency virus (HIV)/HCV-coinfected patients.

METHODS

We performed a cross-sectional study in 220 patients who were genotyped for CXCL9-11 polymorphisms (CXCL9 rs10336, CXCL10 rs3921, and CXCL11 rs4619915) using GoldenGate assay. Three outcome variables related to liver fibrosis were studied: (1) F ≥ 2; (2) APRI ≥ 2; and (3) FIB-4 ≥ 3.25.

RESULTS

The percentage of patients with significant liver fibrosis (F ≥ 2, APRI ≥ 2, and FIB-4 ≥ 3.25) was significantly higher for CXCL9 rs10336 TT (P = 0.046, P = 0.010, and P = 0.046, respectively), CXCL10 rs3921 GG (P = 0.046, P = 0.011, and P = 0.049, respectively), and CXCL11 rs4619915 AA (P = 0.035, P = 0.014, and P = 0.057, respectively) genotypes. Moreover, the greater likelihood of having significant liver fibrosis (F ≥ 2, APRI ≥ 2, and FIB-4 ≥ 3.25) was found in carriers of CXCL9 rs10336 TT and CXCL10 rs3921 GG [adjusted odds ratio (aOR) > 2 (P < 0.05)]. These trends were significantly more pronounced in patients infected with HCV-genotype 1 (GT1) [aOR > 3 (P < 0.05)]. Moreover, TGA haplotype showed higher odds for having values of APRI ≥ 2 (aOR = 2.4; P = 0.012) when we considered all patients. This elevated risk for significant liver fibrosis was better represented in patients infected with HCV-GT1, where TGA haplotype had increased odds for having values of F ≥ 2 (aOR = 1.9; P = 0.045), APRI ≥ 2 (aOR = 3.2; P = 0.009), and FIB-4 ≥ 3.25 (aOR = 3.3; P = 0.026).

CONCLUSIONS

The homozygosity for the minor alleles CXCL9 rs10336 (T), CXCL10 rs3921 (G), and CXCL11 rs4619915 (A) is associated with the higher likelihood of significant liver fibrosis in HIV-infected patients coinfected with HCV-GT1.

Common variants of chemokine receptor gene CXCR3 and its ligands CXCL10 and CXCL11 associated with vascular permeability of dengue infection in peninsular Malaysia

Dengue causes significantly more human disease than any other arboviruses. It causes a spectrum of illness, ranging from mild self-limited fever, to severe and fatal dengue hemorrhagic fever, as evidenced by vascular leakage and multifactorial hemostatic abnormalities. There is no specific treatment available till date. Evidence shows that chemokines CXCL10, CXCL11 and their receptor CXCR3 are involved in severity of dengue, but their genetic association with the susceptibility of vascular leakage during dengue infection has not been reported. We genotyped 14 common variants of these candidate genes in 176 patients infected with dengue. rs4859584 and rs8878 (CXCL10) were significantly associated with vascular permeability of dengue infection (P < 0.05); while variants of CXCL11 showed moderate significance of association (P = 0.0527). Haplotype blocks were constructed for genes CXCL10 and CXCL11 (5 and 7 common variants respectively). Haplotype association tests performed revealed that, “CCCCA” of gene CXCL10 and “AGTTTAC” of CXCL11 were found to be significantly associated with vascular leakage (P = 0.0154 and 0.0366 respectively). In summary, our association study further strengthens the evidence of the involvement of CXCL10 and CXCL11 in the pathogenesis of dengue infection.

CXCL9 is a prognostic marker in patients with liver cirrhosis receiving transjugular intrahepatic portosystemic shunt

BACKGROUND & AIMS

Inflammation, collagen deposition and tissue remodelling are involved in the pathogenesis and complications of cirrhosis with portal hypertension. CXCL9 and other chemokines play an important role in these processes and have been associated with liver injury and complications of liver disease in humans. However, their predictive value in patients with cirrhosis and portal hypertension remains to be established.

METHODS

103 patients with liver cirrhosis who had received TIPS (transjugular intrahepatic portosystemic shunt) were included into this study. The TIPS indication was either refractory ascites or recurrent bleeding. Before and after the TIPS procedure portal and hepatic venous blood samples were obtained in 78 patients. In 25 patients blood samples were obtained from the portal vein, hepatic vein, right atrium and cubital vein at TIPS insertion. Serum levels of CXCL9 were measured by cytometric bead array and correlated with clinical parameters and overall outcome.

RESULTS

Portal venous levels of CXCL9 decreased after TIPS. Child-Pugh score, refractory ascites, renal dysfunction and alcoholic aetiology of cirrhosis were associated with increased CXCL9 levels. Importantly, low levels of CXCL9 in portal and hepatic vein samples were prognostic factors for the survival of patients receiving TIPS during long-time follow-up.

CONCLUSIONS

The CXCR3 ligand CXCL9 affects the liver and/or is released by the liver and thereby might contribute to hepatic and extrahepatic organ dysfunction. Elevated levels of CXCL9 are associated with shorter survival in cirrhotic patients with severe portal hypertension receiving TIPS. This chemokine should be further evaluated as a novel biomarker for the outcome in patients with cirrhosis and portal hypertension and its modulation as a new therapeutic strategy.

Fatty Acids Induce a Pro-Inflammatory Gene Expression Profile in Huh-7 Cells That Attenuates the Anti-HCV Action of Interferon

The pathogenesis of nonalcoholic steatohepatitis is primarily an immune-driven disease and a known factor associated with treatment failure of chronic hepatitis C with interferon (IFN) and ribavirin. We studied the hepatocyte response in a model of steatosis at the transcriptome level and the antiviral action of IFN against hepatitis C virus (HCV) in this setting. In this study, we have shown that lipid loading (oleic acid and palmitic acid, OA:PA) of Huh-7 cells leads to increased expression of classical interferon-stimulated genes (ISGs) and NF-κβ-dependent pro-inflammatory genes. A selective blocker of Toll-like receptor (TLR)2 signaling suppressed NF-κβ promoter activity by OA:PA, suggesting that free fatty acids (FFAs) act as a TLR2 pathogen-associated molecular pattern. Furthermore, in the presence of OA:PA, IFN stimulation and HCV infection (Jc1) increased ISG expression. Somewhat counterintuitive to the increase in ISGs, the anti-HCV activity of IFN was attenuated in the presence of OA:PA. Interestingly, the combination of OA:PA, HCV, and IFN-α stimulation resulted in a significant increase in CXCL8 protein production, a cytokine known to have anti-IFN modulating activity. Thus, in an in vitro model of steatosis, the FFAs OA and PA drive an NF-κβ-dependent inflammatory and ISG gene expression profile via TLR2 activation. Furthermore, FFA synergistically increases IFN-driven gene expression that may account for HCV treatment failure in vivo.

A zebrafish model for subgenomic hepatitis C virus replication

Persistent infection with hepatitis C virus (HCV) is a major risk factor in the development of hepatocellular carcinoma. The elucidation of the pathogenesis of HCV-associated liver disease is hampered by the absence of an appropriate small animal model. Zebrafish exhibits high genetic homology to mammals, and is easily manipulated experimentally. In this study, we describe the use of a zebrafish model for the analysis of HCV replication mechanisms. As the 5' untranslated region (UTR), the core protein, the non-structural protein 5B (NS5B) and the 3'UTR are essential for HCV replication, we constructed a HCV sub-replicon gene construct including the 4 gene sequences and the enhanced green fluorescent protein (EGFP) reporter gene; these genes were transcribed through the mouse hepatocyte nuclear factor 4 (mHNF4) promoter. By microinjection of the subgenomic replicon vector into zebrafish larvae, the virus was easily detected by observing EGFP fluorescence in the liver. The positive core and NS5B signals showed positive expression of the HCV gene construct in zebrafish by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. Importantly, the negative strand sequence of the HCV subgenomic RNA was detected by RT-PCR and hybridization in situ, demonstrating that the HCV sub-replicon has positive replication activity. Furthermore, the hybridization signal mainly appeared in the liver region of larvae, as detected by the sense probe of the core protein or NS5B, which confirmed that the sub-replicon amplification occurred in the zebrafish liver. The amplification of the sub-replicon caused alterations in the expression of certain genes, which is similar to HCV infection in human liver cells. To verify the use of this zebrafish model in drug evaluation, two drugs against HCV used in clinical practice, ribavirin and oxymatrine, were tested and these drugs showed significant inhibition of replication of the HCV sub-replicon in the larvae. In conclusion, this zebrafish model of HCV may prove to be a novel and simple in vivo model for the study of the mechanisms of HCV replication and may also prove useful in the disovery of new anti-HCV drugs.

Pretreatment serum macrophage inflammatory protein (MIP)-1 levels predict sustained virological responses to re-treatment in patients with chronic hepatitis C virus infection

BACKGROUND

There are few predictors of the virological response in patients who are re-treated with antiviral therapies. In this study, we evaluated the levels of chemokines that bind to C-C chemokine receptor type 5 (CCR5) and their impact on combination therapy in both treatment-naïve and treatment-experienced patients chronically infected with hepatitis C virus (HCV).

METHODS

Longitudinal analysis of CCR5 chemokines was performed using the multiplex Bio-Rad 27-plex assay in 56 treatment-naïve and 24 treatment-experienced patients with chronic HCV infection during combination therapy with peginterferon alfa and ribavirin. A group of healthy donors was included as the control (n=11).

RESULTS

The pretreatment level of macrophage inflammatory protein 1 (MIP-1) was determined to be an independent predictor, with an ideal predictive threshold for sustained virological response of 95.23 pg/ml. A rapid decline in HCV RNA was observed in patients with a pretreatment MIP-1 level of <95.23 pg/ml, while a slow reduction was measured in patients with levels of ≥95.23 pg/ml (p=0.014). Of note, the dynamics of MIP-1 further indicated that a lower level at baseline and at treatment week 12 was significantly associated with a favorable outcome of antiviral therapy (p=0.014), especially in treatment-experienced patients (p=0.04), while a higher level of MIP-1beta correlated with the elevation of transaminases.

CONCLUSIONS

Serum MIP-1 is an independent and effective predictor of early and sustained virological response in chronically HCV-infected patients undergoing re-treatment.

Detection of allele specific differences in IFNL3 (IL28B) mRNA expression

BACKGROUND

Variants of the interferon-lambda3 (IFNL3) gene have been associated with both spontaneous and treatment induced clearance of HCV infection. Attempts to link polymorphisms of the IFNL3 gene with variation in the level of IFNL3 expression have been inconclusive. This is partially due to the difficulty to design assays distinguishing IFNL3 from IFNL2.

METHODS

In this study an allele specific real-time PCR (RT-PCR) assay was developed which allows the relative quantification of the two IFNL3 transcripts in cells heterozygous for SNP IFNL3.rs4803217 in the 3'UTR of the IFNL3 gene. This SNP is in strong linkage disequilibrium (LD) with the predictive marker rs12979860.

RESULTS

Raji cells showed two-fold increased levels of IFNL3.rs4803217 C-allele expression. In peripheral blood mononuclear cells (PBMCs) of eight uninfected donors, two donors showed increased IFNL3.rs4803217 C-allele expression.

CONCLUSION

This indicates that allele specific differences in IFNL3 expression vary between individuals and might contribute to the variety of outcomes in HCV infected patients.

Osteopontin is an important mediator of alcoholic liver disease via hepatic stellate cell activation

AIM: To investigate over-expression of Osteopontin (OPN) pathway expression and mechanisms of action in human alcoholic liver disease (ALD), in vivo and in vitro acute alcohol models.

METHODS: OPN pathway was evaluated in livers from patients with progressive stages of human ALD and serum from drinkers with and without liver cirrhosis. In vitro stellate LX2 cells exposed to acute alcohol and in vivo in acute alcoholic steatosis mouse models were also investigated for OPN pathway expression and function. WT and OPN^-/- mice were administered an acute dose of alcohol and extent of liver injury was examined by histopathology and liver biochemistry after 16-24 h. The causative role of OPN was studied in OPN knockout animals and in vitro in stellate LX2 cells, utilizing siRNA, aptamer and neutralizing antibodies to block OPN and OPN pathway. OPN pathway expression and downstream functional consequences were measured for signaling by Western blotting, plasmin activation by spectrophotometric assays and cell migration by confocal imaging and quantitation.

RESULTS: OPN expression positively correlated with disease severity in patients with progressive stages of ALD. In vivo, associated with alcoholic steatosis, a single dose of acute alcohol significantly increased hepatic OPN mRNA and protein, and a cleaved OPN form in a dose dependent manner. OPN mRNA and secreted OPN also increased in parallel with activation of LX2 stellate cells within 4 h of a single dose of alcohol. Expression of OPN receptors, αvβ3-integrin and CD44, increased in human ALD, and in vivo and in vitro with alcohol administration. This was accompanied by downstream phosphorylation of Akt and Erk, increased mRNA expression of several fibrogenesis, fibrinolysis and extracellular matrix pathway genes, plasmin activation and hepatic stellate cell (HSC) migration. Inhibition of OPN and OPN-receptor mediated signaling partially inhibited alcohol-induced HSC activation, plasmin activity and cell migration.

CONCLUSION: OPN is a key mediator of the alcohol-induced effects on hepatic stellate cell functions and liver fibrogenesis.

Adaptive immune response during hepatitis C virus infection

Hepatitis C virus (HCV) infection affects about 170 million people worldwide and it is a major cause of liver cirrhosis and hepatocellular carcinoma. HCV is a hepatotropic non-cytopathic virus able to persist in a great percentage of infected hosts due to its ability to escape from the immune control. Liver damage and disease progression during HCV infection are driven by both viral and host factors. Specifically, adaptive immune response carries out an essential task in controlling non-cytopathic viruses because of its ability to recognize infected cells and to destroy them by cytopathic mechanisms and to eliminate the virus by non-cytolytic machinery. HCV is able to impair this response by several means such as developing escape mutations in neutralizing antibodies and in T cell receptor viral epitope recognition sites and inducing HCV-specific cytotoxic T cell anergy and deletion. To impair HCV-specific T cell reactivity, HCV affects effector T cell regulation by modulating T helper and Treg response and by impairing the balance between positive and negative co-stimulatory molecules and between pro- and anti-apoptotic proteins. In this review, the role of adaptive immune response in controlling HCV infection and the HCV mechanisms to evade this response are reviewed.

Positioning of leukocyte subsets in the portal and lobular compartments of hepatitis C virus-infected liver correlates with local chemokine expression

BACKGROUND AND AIM

Chronic hepatitis C virus infection is characterized by infiltration of a mixed population of leukocytes into portal tracts and infiltration almost exclusively by CD8+ T cells into lobules of the liver. This pattern of leukocyte recruitment is likely to be orchestrated in a cell-specific fashion by local chemokine expression.

METHODS

Portal or lobular tissues were isolated by laser capture microdissection from 17 liver biopsy specimens to examine regional gene expression of a panel of chemokine ligands and receptors. The biopsies were also stained immunohistochemically to enumerate regional cell numbers.

RESULTS

Expression of multiple chemokine ligands and receptors was evident, although few correlated with leukocyte numbers. In the lobule, expression of CXCL10 correlated with T-cell subsets (CD3+, P = 0.0002; CD4+, P = 0.0053; and CD8+, P = 0.0061), as did CCL5 (CD3+, P = 0.0005; CD8+, P = 0.0199) and CCL3 (CD3+, P = 0.0016; CD8+, P = 0.008). In the portal tracts, expression of CXCL10 and CCL5 was correlated with CD8+ T-cell numbers (P = 0.0040 and P = 0.0114, respectively), whereas CXCL13 was strongly correlated with CD20+ B-cell numbers (P < 0.0001). CXCR3 expression correlated with CD3+ and CD4+ T cells (P < 0.0001 and P = 0.0208, respectively), CCR5 with CD8+ T cells (P < 0.0001), and CXCR5 with CD20+ B-cell infiltration (P = 0.0022).

CONCLUSION

CXCR3, CCR5, and CXCR5 and their ligands form key elements of the "zip code" responsible for regional localization of specific lymphocyte subsets in the HCV-infected liver.

The role of chemokines in hepatitis C virus-mediated liver disease

The hepatitis C virus (HCV) is a global health problem affecting more than 170 million people. A chronic HCV infection is associated with liver fibrosis, liver cirrhosis and hepatocellular carcinoma. To enable viral persistence, HCV has developed mechanisms to modulate both innate and adaptive immunity. The recruitment of antiviral immune cells in the liver is mainly dependent on the release of specific chemokines. Thus, the modulation of their expression could represent an efficient viral escape mechanism to hamper specific immune cell migration to the liver during the acute phase of the infection. HCV-mediated changes in hepatic immune cell chemotaxis during the chronic phase of the infection are significantly affecting antiviral immunity and tissue damage and thus influence survival of both the host and the virus. This review summarizes our current understanding of the HCV-mediated modulation of chemokine expression and of its impact on the development of liver disease. A profound knowledge of the strategies used by HCV to interfere with the host's immune response and the pro-fibrotic and pro-carcinogenic activities of HCV is essential to be able to design effective immunotherapies against HCV and HCV-mediated liver diseases.

Listr1 locus regulates innate immunity against Listeria monocytogenes infection in the mouse liver possibly through Cxcl11 polymorphism

Inbred stains of mice display differential susceptibility to infection with the common foodborne pathogen Listeria monocytogenes (Lm). Previously, Listr1 and Listr2, two genetic loci that control differential sensitivity to Lm infection between BALB/cByJ and C57BL/6ByJ mice, were identified. To analyze the role of Listr1 in innate immune responses, we employed congenic mice (C.B6By-Listr1/Rag2 (-/-) ) bearing the C57BL/6ByJ-derived Listr1 locus on a BALB/c-Rag2 (-/-) background. Consistent with the results of a previous genetic analysis, the congenic mice showed increased susceptibility to Lm infection. The bacterial burden in the liver between the congenic and control lines was significantly different (P < 0.05) from 24 h postinfection with Lm. Analysis of genes within the Listr1 locus identified a frameshift mutation in the Cxcl11 gene of the C57BL/6 strain that prevents production of the mature chemokine CXCL11. No differences in inflammatory cell infiltration or cells expressing CXCR3 and CXCR7 which are the receptors of CXCL11 occurred because of CXCL11 deficiency in the congenic mice spleens. However, these mice lacked a distinct population of CD14(+) positive resident mononuclear cells that express intermediate levels of CXCR3 and CXCR7 in the liver. There were fewer microabscesses in the liver of CXCL11-deficient mice during the early stage of infection, which is consistent with their decreased ability to resist Lm. Our results, when taken together, show that the Listr1 locus plays an important role in early control of Lm infection in the mouse liver and that Cxcl11 is a candidate gene for disease severity within this locus.

Signal transducer and activator of transcription 3 is a proviral host factor for hepatitis C virus

Host factors play an important role in all facets of the hepatitis C virus (HCV) life cycle and one such host factor is signal transducer and activator of transcription 3 (STAT3). The HCV core protein has been shown to directly interact with and activate STAT3, while oxidative stress generated during HCV replication in a replicon-based model also induced STAT3 activation. However, despite these findings the precise role of STAT3 in the HCV life cycle remains unknown. We have established that STAT3 is actively phosphorylated in the presence of replicating HCV. Furthermore, expression of a constitutively active form of STAT3 leads to marked increases in HCV replication, whereas, conversely, chemical inhibition and small interfering RNA (siRNA) knockdown of STAT3 leads to significant decreases in HCV RNA levels. This strongly implicates STAT3 as a proviral host factor. As STAT3 is a transcription factor, up-regulation of a distinct set of STAT3-dependent genes may create an environment that is favorable for HCV replication. However, STAT3 has recently been demonstrated to positively regulate microtubule (MT) dynamics, by way of a direct sequestration of the MT depolymerizing protein Stathmin 1 (STMN1), and we provide evidence that STAT3 may exert its effect on the HCV life cycle by way of positive regulation of MT dynamics.

CONCLUSION

We have demonstrated that STAT3 plays a role in the life cycle of HCV and have clarified the role of STAT3 as a proviral host factor.

The role of chemokines in acute and chronic hepatitis C infection

Hepatitis C imposes a significant burden on global healthcare. Chronic infection is associated with progressive inflammation of the liver which typically manifests in cirrhosis, organ failure and cancer. By virtue of elaborate evasion strategies, hepatitis C virus (HCV) succeeds as a persistent human virus. It has an extraordinary capacity to subvert the immune response enabling it to establish chronic infections and associated liver disease. Chemokines are low molecular weight chemotactic peptides that mediate the recruitment of inflammatory cells into tissues and back into the lymphatics and peripheral blood. Thus, they are central to the temporal and spatial distribution of effector and regulatory immune cells. The interactions between chemokines and their cognate receptors help shape the immune response and therefore, have a major influence on the outcome of infection. However, chemokines represent a target for modulation by viruses including the HCV. HCV is known to modulate chemokine expression in vitro and may therefore enable its survival by subverting the immune response in vivo through altered leukocyte chemotaxis resulting in impaired viral clearance and the establishment of chronic low-grade inflammation. In this review, the roles of chemokines in acute and chronic HCV infection are described with a particular emphasis placed on chemokine modulation as a means of immune subversion. We provide an in depth discussion of the part played by chemokines in mediating hepatic fibrosis while addressing the potential applications for these chemoattractants in prognostic medicine.

HIV and co-infections

Despite significant reductions in morbidity and mortality secondary to availability of effective combination anti-retroviral therapy (cART), human immunodeficiency virus (HIV) infection still accounts for 1.5 million deaths annually. The majority of deaths occur in sub-Saharan Africa where rates of opportunistic co-infections are disproportionately high. In this review, we discuss the immunopathogenesis of five common infections that cause significant morbidity in HIV-infected patients globally. These include co-infection with Mycobacterium tuberculosis, Cryptococcus neoformans, hepatitis B virus, hepatitis C virus, and Plasmodium falciparum. Specifically, we review the natural history of each co-infection in the setting of HIV, the specific immune defects induced by HIV, the effects of cART on the immune response to the co-infection, the pathogenesis of immune restoration disease (IRD) associated with each infection, and advances in the areas of prevention of each co-infection via vaccination. Finally, we discuss the opportunities and gaps in knowledge for future research.

High Circulating Chemokines (C-X-C Motif) Ligand 9, and (C-X-C Motif) Ligand 11, in Hepatitis C-Associated Cryoglobulinemia

(C-X-C motif) ligand 9 and (C-X-C motif) ligand 11 (CXCL9 and CXCL11), are potent chemoattractants for activated T cells, and play an important role in T helper 1 (Th) 1 cell recruitment in chronic hepatitis C. No study has evaluated CXCL9, together with CXCL11, circulating levels in patients with mixed cryoglobulinemia and hepatitis C (MC+HCV-p). The aim of the present study therefore was to measure serum CXCL9, and CXCL11 levels, in MC+HCV-p, and to relate the findings to the clinical phenotype. Serum CXCL9 and CXCL11 were measured in 71 MC+HCV-p and in matched controls. MC+HCV-p showed significantly higher mean CXCL9 and CXCL11 levels than controls (P < 0.001, for both), in particular, in 32 patients with active vasculitis (P < 0.001). By defining high CXCL9 or CXCL11 level as a value of at least 2 SD above the mean value of the control group (> 100 pg/mL): 89% MC+HCV-p and 5% controls had high CXCL9 (P < 0.0001, chi-square); 90% MC+HCV-p and 6% controls had high CXCL11 (P < 0.0001, chi-square). In a multiple linear regression model of CXCL9 vs age, ALT, CXCL11, only CXCL11 was significantly (r = 0.452, P < 0.0001) and independently related to CXCL9. Our study demonstrates in MC+HCV-p vs controls: (i) high serum CXCL9, and CXCL11, significantly associated with the presence of active vasculitis; (ii) a strong relationship between circulating CXCL9 and CXCL11. Future studies on a larger cohort of patients are needed to evaluate the relevance of serum CXCL9 and CXCL11 determination as clinico-prognostic marker of MC+HCV.

Osteopontin increases hepatocellular carcinoma cell growth in a CD44 dependant manner

AIM: To investigate the role of osteopontin (OPN) and its splice variants in the proliferation of hepatocellular carcinoma (HCC).

METHODS: The expression of OPN variants in HCC cell lines as well as HCC tissue samples and non-tumour tissue was studied using polymerase chain reaction. OPN variant cDNAs were cloned into a mammalian expression vector allowing both transient expression and the production of stable OPN expressing cell lines. OPN expression was studied in these cells using Western blotting, immunofluoresnce and enzyme linked immunosorbent assay. A CD44 blocking antibody and siRNA targeting of CD44 were used to examine the role of this receptor in the OPN stimulated cell growth observed in culture. Huh-7 cells stably expressing either OPN-A, -B or -C were injected subcutaneously into the flanks of nude mice to observe in vivo tumour growth. Expression of OPN mRNA and protein in these tumours was examined using reverse transcription-polymerase chain reaction and immunohistochemistry.

RESULTS: OPN is expressed in HCC in 3 forms, the full length OPN-A and 2 splice variants OPN-B and -C. OPN variant expression was noted in HCC tissue as well as cognate surrounding cirrhotic liver tissue. Expression of these OPN variants in the HCC derived cell line Huh-7 resulted in secretion of OPN into the culture medium. Transfer of OPN conditioned media to naïve Huh-7 and HepG2 cells resulted in significant cell growth suggesting that all OPN variants can modulate cell proliferation in a paracrine manner. Furthermore the OPN mediated increase in cellular proliferation was dependent on CD44 as only CD44 positive cell lines responded to OPN conditioned media while siRNA knockdown of CD44 blocked the proliferative effect. OPN expression also increased the proliferation of Huh-7 cells in a subcutaneous nude mouse tumour model, with Huh-7 cells expressing OPN-A showing the greatest proliferative effect.

CONCLUSION: This study demonstrates that OPN plays a significant role in the proliferation of HCC through interaction with the cell surface receptor CD44. Modulation of this interaction could represent a novel strategy for the control of HCC.

The CXCR3(+)CD56Bright phenotype characterizes a distinct NK cell subset with anti-fibrotic potential that shows dys-regulated activity in hepatitis C

BACKGROUND

In mouse models, natural killer (NK) cells have been shown to exert anti-fibrotic activity via killing of activated hepatic stellate cells (HSC). Chemokines and chemokine receptors critically modulate hepatic recruitment of NK cells. In hepatitis C, the chemokine receptor CXCR3 and its ligands have been shown to be associated with stage of fibrosis suggesting a role of these chemokines in HCV associated liver damage by yet incompletely understood mechanisms. Here, we analyzed phenotype and function of CXCR3 expressing NK cells in chronic hepatitis C.

METHODS

Circulating NK cells from HCV-infected patients (n = 57) and healthy controls (n = 27) were analyzed with respect to CXCR3 and co-expression of different maturation markers. Degranulation and interferon-γ secretion of CXCR3(+) and CXCR3(-) NK cell subsets were studied after co-incubation with primary human hepatic stellate cells (HSC). In addition, intra-hepatic frequency of CXCR3(+) NK cells was correlated with stage of liver fibrosis (n = 15).

RESULTS

We show that distinct NK cell subsets can be distinguished based on CXCR3 surface expression. In healthy controls CXCR3(+)CD56Bright NK cells displayed strongest activity against HSC. Chronic hepatitis C was associated with a significantly increased frequency of CXCR3(+)CD56Bright NK cells which showed impaired degranulation and impaired IFN-γ secretion in response to HSC. Of note, we observed intra-hepatic accumulation of this NK cell subset in advanced stages of liver fibrosis.

CONCLUSION

We show that distinct NK cell subsets can be distinguished based on CXCR3 surface expression. Intra-hepatic accumulation of the functionally impaired CXCR3(+)CD56Bright NK cell subset might be involved in HCV-induced liver fibrosis.

CD44 participates in IP-10 induction in cells in which hepatitis C virus RNA is replicating, through an interaction with Toll-like receptor 2 and hyaluronan

The mechanisms of induction of liver injury during chronic infection with hepatitis C virus (HCV) are not well understood. Gamma interferon (IFN-γ)-inducible protein 10 (IP-10), a member of the CXC chemokine family, is expressed in the liver of chronic hepatitis C (CHC) patients and selectively recruits activated T cells to the sites of inflammation. Recently, it was shown that a low plasma concentration of IP-10 in CHC patients was closely associated with the outcome of antiviral therapy. In this study, we examined the role of the Toll-like receptor (TLR) pathway on IP-10 production in cells replicating HCV. Among the CXC chemokines, the expression of IP-10 was specifically increased in cells replicating HCV upon stimulation with conventional TLR2 ligands. The enhancement of IP-10 production upon stimulation with TLR2 ligands in cells replicating HCV induced CD44 expression. CD44 is a broadly distributed type I transmembrane glycoprotein and a receptor for the glycosaminoglycan hyaluronan (HA). In CHC patients, the expression of HA in serum has been shown to increase in accord with the progression of liver fibrosis, and HA also works as a ligand for TLR2. In the present study, IP-10 production upon HA stimulation was dependent on the expression of TLR2 and CD44, and a direct association between TLR2 and CD44 was observed. These results suggest that endogenous expression of HA in hepatocytes in CHC patients participates in IP-10 production through an engagement of TLR2 and CD44.