Impact of HCV genetic differences on pathobiology of disease

Peroxisome proliferator-activated receptors: Key regulators of tumor progression and growth

One of the main causes of death on the globe is cancer. Peroxisome-proliferator-activated receptors (PPARs) are nuclear hormone receptors, including PPARα, PPARδ and PPARγ, which are important in regulating cancer cell proliferation, survival, apoptosis, and tumor growth. Activation of PPARs by endogenous or synthetic compounds regulates tumor progression in various tissues. Although each PPAR isotype suppresses or promotes tumor development depending on the specific tissues or ligands, the mechanism is still unclear. PPARs are receiving interest as possible therapeutic targets for a number of disorders. Numerous clinical studies are being conducted on PPARs as possible therapeutic targets for cancer. Therefore, this review will focus on the existing and future uses of PPARs agonists and antagonists in treating malignancies. PubMed, Science Direct, and Scopus databases were searched regarding the effect of PPARs on various types of cancers until the end of May 2023. The results of the review articles showed the therapeutic influence of PPARs on a wide range of cancer on in vitro, in vivo and clinical studies. However, further experimental and clinical studies are needed to be conducted on the influence of PPARs on various cancers.

Gender-Specific Differences in Serum Sphingomyelin Species in Patients with Hepatitis C Virus Infection-Sphingomyelin Species Are Related to the Model of End-Stage Liver Disease (MELD) Score in Male Patients

Hepatitis C virus (HCV) replication depends on cellular sphingomyelin (SM), but serum SM composition in chronic HCV infection has been hardly analyzed. In this work, 18 SM species could be quantified in the serum of 178 patients with chronic HCV infection before therapy with direct-acting antivirals (DAAs) and 12 weeks later, when therapy was completed. Six SM species were higher in the serum of females than males before therapy and nine at the end of therapy; thus, sex-specific analysis was performed. Type 2 diabetes was associated with lower serum levels of SM 36:2;O2 and 38:2;O2 in men. Serum SM species did not correlate with the viral load in both sexes. Of note, three SM species were lower in males infected with HCV genotype 3 in comparison to genotype 1 infection. These SM species normalized after viral cure. SM 38:1;O2, 40:1;O2, 41:1;O2, and 42:1;O2 (and, thus, total SM levels) were higher in the serum of both sexes at the end of therapy. In males, SM 39:1;O2 was induced in addition, and higher levels of all of these SM species were already detected at 4 weeks after therapy has been started. Serum lipids are related to liver disease severity, and in females 15 serum SM species were low in patients with liver cirrhosis before initiation of and after treatment with DAAs. The serum SM species did not correlate with the model of end-stage liver disease (MELD) score in the cirrhosis and the non-cirrhosis subgroups in females. In HCV-infected male patients, nine SM species were lower in the serum of patients with cirrhosis before DAA treatment and eleven at the end of the study. Most of the SM species showed strong negative correlations with the MELD score in the male cirrhosis patients before DAA treatment and at the end of therapy. Associations of SM species with the MELD score were not detected in the non-cirrhosis male subgroup. In summary, the current analysis identified sex-specific differences in the serum levels of SM species in HCV infection, in liver cirrhosis, and during DAA therapy. Correlations of SM species with the MELD score in male but not in female patients indicate a much closer association between SM metabolism and liver function in male patients.

Decoupled Glucose and Lipid Metabolic Recovery after Viral Clearance in Direct-Acting Antiviral-Treated HCV Patients: A 3-Year Prospective Cohort Study

BACKGROUND/AIM

The recovery pattern of hepatitis C virus (HCV)-associated metabolic alteration after sustained virological response (SVR) following direct-acting antivirals (DAAs) remains elusive.

METHODS

A prospective cohort study of chronic HCV-infected (CHC) patients (n = 415) receiving DAAs (n = 365) was conducted. Metabolic profiles were examined in SVR patients (n = 360) every 3-6 months after therapy and compared with those of sex- and age-matched controls (n = 470).

RESULTS

At baseline, of 415, 168 (40.5%) had insulin resistance (IR). The following were associated: levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TGs), HCV RNA, fibrosis-4 score, and interferon-λ3-rs12979860 genotype with total cholesterol (TC) levels; and TG levels and BMI with HOMA-IR. Over a 3-year follow-up, in SVR patients, BMI and TC levels and TG/HDL-C ratios increased from baseline, while HOMA-IR trended downward by 72 weeks after therapy and then increased. The increased HDL-C levels began to decrease after 72 weeks after therapy. TC and HOMA-IR were negatively associated with each other until 24 weeks after therapy. Earlier increases in BMI and decreases in HOMA-IR were noted in SVR patients with than in those without baseline IR. Compared with controls, in the subgroup without baseline IR, SVR patients had increased BMI and HOMA-IR levels. Metabolic profiles were similar between SVR patients and controls in the subgroup with baseline IR.

CONCLUSIONS

In SVR patients treated with DAAs, the recovery of altered lipid and glucose metabolism was not coupled until 72-week post-therapy, when HOMA-IR reached its nadir. SVR patients with baseline IR recovered from HCV-associated metabolic alterations earlier than those without baseline IR.

Trends of Late Presentation to Care in Patients with Chronic Hepatitis C during a 10-Year Period in Croatia

Late presentation to care is the major obstacle to receiving treatment for chronic hepatitis C (CHC). Our aim was to analyze the prevalence and trends of late presenters (LP) at first consultations in Croatia during a 10-year period. This retrospective cross-sectional study included all adult CHC patients (n = 854) entering specialist medical care at the University Hospital for Infectious Diseases Zagreb between 2009 and 2018. LP was defined as liver stiffness measurement ≥ 9.5 kPa or biopsy METAVIR F ≥ 3. During the study period, mean patients' age increased from 37 to 52 years while HCV genotype distribution changed leading to the replacement of genotype 1b with 1a (g1b 32% to 21%; g1a 19% to 38%). A total of 320 (37.4%) were LP; they were older (47.5, IQR 40.5-57.6), and more commonly infected with g1b (34.1%) and g3 (42.5%). The prevalence of LP significantly increased from 31.9% in 2009 to 46.5% in 2018. Late presentation for care of CHC is increasing in Croatia suggesting a gap of diagnosing strategies in patients over 50 years.

The Circadian Clock, the Immune System, and Viral Infections: The Intricate Relationship Between Biological Time and Host-Virus Interaction

Living beings spend their lives and carry out their daily activities interacting with environmental situations that present space-time variations and that involve contact with other life forms, which may behave as commensals or as invaders and/or parasites. The characteristics of the environment, as well as the processes that support the maintenance of life and that characterize the execution of activities of daily life generally present periodic variations, which are mostly synchronized with the light–dark cycle determined by Earth’s rotation on its axis. These rhythms with 24-h periodicity, defined as circadian, influence events linked to the interaction between hosts and hosted microorganisms and can dramatically determine the outcome of this interplay. As for the various pathological conditions resulting from host–microorganism interactions, a particularly interesting scenario concerns infections by viruses. When a viral agent enters the body, it alters the biological processes of the infected cells in order to favour its replication and to spread to various tissues. Though our knowledge concerning the mutual influence between the biological clock and viruses is still limited, recent studies start to unravel interesting aspects of the clock–virus molecular interplay. Three different aspects of this interplay are addressed in this mini-review and include the circadian regulation of both innate and adaptive immune systems, the impact of the biological clock on viral infection itself, and finally the putative perturbations that the virus may confer to the clock leading to its deregulation.

An update on hepatitis C virus genotype distribution in Jordan: a 12-year retrospective study from a tertiary care teaching hospital in Amman

Background

Nucleic acid hybridization (NAH) of hepatitis C virus (HCV) is a practical and reliable tool for virus genotyping. Genotype assignment is an important factor in the prediction of treatment success in chronic hepatitis C patients. The aim of this study was to determine the genotype distribution among HCV clinical isolates in Jordan between 2007 and 2018.

Methods

Electronic and paper-based clinical data registry records from 2007 to 2018 at the Jordan University Hospital (JUH) were retrospectively examined for individuals with HCV genotype, HCV viral load, and alanine aminotransferase (ALT) testing results. Genotype determination was based on NAH technique using the HCV 5′ untranslated region (5′ UTR) with 386 requests available from 342 unique individuals.

Results

A total of 263 out of 342 unique individuals (76.9%) had genotyping results available for final analysis with 259 individuals each having a single genotyping result. The most common HCV genotypes in the study were: genotype 4 (n = 142, 54.0%), genotype 1 (n = 87, 33.1%), genotype 3 (n = 16, 6.1%), genotype 2 (n = 9, 3.4%), other undetermined genotypes (n = 5, 1.9%) and mixed infections (n = 4, 1.5%). Sub-genotyping results were available for 46 individuals as follows: sub-genotype 4c/d (n = 13, 28.3%), sub-genotype 1a (n = 11, 23.9%), sub-genotype 1b (n = 10, 21.7%), sub-genotype 4a (n = 8, 17.4%), sub-genotype 3a (n = 2, 4.3%), sub-genotypes 2a/c and 4 h (n = 1, 2.2% for both). Individuals infected with genotype 1 showed higher viral load when compared to those infected with genotype 4 (p = 0.048, t-test). Younger HCV-infected individuals (< 52 years) had higher ALT levels compared to older individuals (p = 0.036, t-test). Self-reported risk factors for HCV acquisition included: history of previous surgery, invasive dental procedures, and blood transfusion, delivery at home, circumcision at home and wet cupping therapy (hijama).

Conclusions

High genetic diversity of HCV was found in Jordan, with genotypes 4 and 1 as the most prevalent genotypes co-circulating in the country. Potential impact of virus genotype on disease markers (viral load, ALT) was detected and needs further assessment. The study can be helpful to plan for future prevention and management of HCV infection in Jordan.

Large Outbreak of Hepatitis C Virus Associated With Drug Diversion by a Healthcare Technician

Background

In May 2012, the New Hampshire (NH) Division of Public Health Services (DPHS) was notified of 4 persons with newly diagnosed hepatitis C virus (HCV) infection at hospital X. Initial investigation suggested a common link to the hospital cardiac catheterization laboratory (CCL) because the infected persons included 3 CCL patients and a CCL technician. NH DPHS initiated an investigation to determine the source and control the outbreak.

Methods

NH DPHS conducted site visits, case patient and employee interviews, medical record and medication use review, and employee and patient HCV testing using enzyme immunoassay for anti-HCV, reverse-transcription polymerase chain reaction for HCV RNA, nonstructural 5B (NS5B) and hypervariable region 1 (HVR1) sequencing, and quasispecies analysis.

Results

HCV HVR1 analysis of the first 4 cases confirmed a common source of infection. HCV testing identified 32 of 1074 CCL patients infected with the outbreak strain, including 3 patients coinfected with >1 HCV strain. The epidemiologic investigation revealed evidence of drug diversion by the HCV-infected technician, evidenced by gaps in controlled medication control, higher fentanyl use during procedures for confirmed cases, and building card key access records documenting the presence of the technician during days when transmission occurred. The employee's status as a traveling technician led to a multistate investigation, which identified additional cases at prior employment sites.

Conclusions

This is the largest laboratory-confirmed drug diversion-associated HCV outbreak published to date. Recommendations to reduce drug diversion risk and to conduct outbreak investigations are provided.

Hepatitis C Virus Infection: Host⁻Virus Interaction and Mechanisms of Viral Persistence

Hepatitis C (HCV) is a major cause of liver disease, in which a third of individuals with chronic HCV infections may develop liver cirrhosis. In a chronic HCV infection, host immune factors along with the actions of HCV proteins that promote viral persistence and dysregulation of the immune system have an impact on immunopathogenesis of HCV-induced hepatitis. The genome of HCV encodes a single polyprotein, which is translated and processed into structural and nonstructural proteins. These HCV proteins are the target of the innate and adaptive immune system of the host. Retinoic acid-inducible gene-I (RIG-I)-like receptors and Toll-like receptors are the main pattern recognition receptors that recognize HCV pathogen-associated molecular patterns. This interaction results in a downstream cascade that generates antiviral cytokines including interferons. The cytolysis of HCV-infected hepatocytes is mediated by perforin and granzyme B secreted by cytotoxic T lymphocyte (CTL) and natural killer (NK) cells, whereas noncytolytic HCV clearance is mediated by interferon gamma (IFN-γ) secreted by CTL and NK cells. A host-HCV interaction determines whether the acute phase of an HCV infection will undergo complete resolution or progress to the development of viral persistence with a consequential progression to chronic HCV infection. Furthermore, these host-HCV interactions could pose a challenge to developing an HCV vaccine. This review will focus on the role of the innate and adaptive immunity in HCV infection, the failure of the immune response to clear an HCV infection, and the factors that promote viral persistence.

Hepatitis B, C and D virus genotypes detected in HBsAg- or anti-HCV-positive people from the Republic of Moldova

In the Republic of Moldova, little is known about hepatitis B, C and D virus (HBV, HCV, HDV) genotypes, although the genetic variant may influence the course and outcome of disease. For HBV genotyping, 301 hepatitis B surface antigen (HBsAg)-positive sera collected in 2010 and 2011 from drug users, prison inmates, commercial sex workers, and the general population in different geographical regions were investigated. The 31 HBsAg-positive sera collected in 2011 were also tested for HDV. Eighty-eight anti-HCV-positive sera collected between 2010 and 2011 from the general population and health care workers were used for HCV genotyping. Phylogenetic analysis of 84 HBV sequences showed that most of the viruses belonged to genotype D (n = 82, 97.6%), predominantly to the subgenotype D1/D2 cluster (n = 75/82, 91.5%). One sequence (74110) clustered as an outlier to this cluster, and six sequences belonged to subgenotype D3. Only two subgenotype A2 sequences were found. Cloning of six samples with ambiguous sequence chromatogram signals showed no mixed infections. Phylogenetic analysis of HCV sequences from 66 patients showed a predominance of subtype 1b (n = 63, 95.5%). Two sequences belonged to subtype 3a, and one to subtype 2a. HDV RNA belonging to genotype 1 was found in two sera (2/31, 6.5%). Thus, genotypes prevalent in Europe were detected for all three hepatitis viruses. For both HBV and HCV, one genotype was dominant, while occasional other variants seem to be restricted to certain cohorts and/or transmission routes.

Subtyping of hepatitis C virus with high resolution mass spectrometry

A proteotyping approach using high resolution mass spectrometry has been applied, for the first time, to subtype the hepatitis C virus based upon detection of one or more signature peptides derived from the E1 and E2 envelope glycoproteins. These signature peptides represent conserved peptide segments within these proteins for particular subtypes of the virus that are found to be unique in mass when compared with the theoretical masses for all peptide segments of translated HCV proteins within a specifically constructed database. The successful application of the approach to three different subtypes of the virus (i.e., 1a, 1b and 2b) is demonstrated for protein and whole virus proteolytic digests. The approach has the potential to replace existing PCR-based subtyping by offering a more direct and cost comparable strategy that is not challenged by mixed infection scenarios.

Hepatitis C genotype distribution in patient and blood donor samples in South Africa for the period 2008-2012

There are limited molecular epidemiological studies of hepatitis C at a national level in South Africa. The introduction of newer treatment modalities for hepatitis C requires knowledge of the genotypes as these may have different prognostic and therapeutic implications. This retrospective study describes genotype distributions of patients attending specialist clinics and a blood donor group studied during the period 2008-2012 in South Africa. Residual samples from diagnostic viral load testing from specialist clinics in South Africa (n=941) and from the South African National Blood Service (n=294) were analysed quantitatively by real-time PCR and genotyped using the Versant line probe assay or sequencing. Genotype 1 was predominant in blood donors (34%), whilst genotype 5a was prevalent in patients (36%). In the blood donor group, genotype 4 was detected for the first time. Genotype 2 was rare in the patient group and not detected in blood donors. Genotype 1 was the predominant genotype in the younger age groups (less than 30 years), whereas genotype 5a was found at higher proportions in the older age groups for both the patient and blood donor groups, comprising more than 60% of genotypes in those older than 50 years. Genotypes 1 and 5 were at highest proportions across all provinces compared to other genotypes. In blood donors, genotype 1 was predominant among Caucasians (43%) and genotype 5a among Blacks (54%). Such information is required for planning the impact on the health sector with regard to newly emerging therapies for hepatitis C and burden of disease.

Disease progression in Chinese patients with hepatitis C virus RNA-positive infection via blood transfusion

The majority of patients with hepatitis C virus (HCV) in China were infected via blood transfusion prior to the year 1996. In this systematic retrospective cohort study, disease progression in 804 consecutive patients with transfusion-acquired HCV is investigated. In addition, the occurrence of compensated cirrhosis, decompensated cirrhosis and hepatocellular carcinoma (HCC) is analyzed among these patients, along with the risk factors for disease progression. Patients with cirrhosis or HCC were classified as the serious development group (SD group) and the remaining patients with chronic hepatitis were classified as the hepatitis group (H group). Significant differences were found between the two groups in age at the time of infection, duration of infection and age at the time of observation. SD group patients were significantly older at the time of transfusion (33.73 vs. 23.56 years; P<0.001), with a significantly longer mean duration of HCV infection (21.88 vs. 21.15 years; P=0.029) compared with that in the H group. Male gender and age at the time of transfusion were significant risk factors for HCC (OR=2.48, P=0.031 and OR=1.07, P=0.002, respectively). Age was a significant risk factor for disease progression in older Chinese patients with transfusion-acquired HCV, and there were significant differences in the prevalence of compensated cirrhosis, decompensated cirrhosis and HCC between the age groups (P<0.001), suggesting that more patients with HCV may develop cirrhosis or HCC in their third and fourth decades of infection. Results of the present study will be helpful for predicting disease progression in Chinese patients with HCV infected via blood transfusion.

Hepatitis C virus relies on lipoproteins for its life cycle

Hepatitis C virus (HCV) infects over 150 million people worldwide. In most cases, HCV infection becomes chronic causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. Viral persistence and pathogenesis are due to the ability of HCV to deregulate specific host processes, mainly lipid metabolism and innate immunity. In particular, HCV exploits the lipoprotein machineries for almost all steps of its life cycle. The aim of this review is to summarize current knowledge concerning the interplay between HCV and lipoprotein metabolism. We discuss the role played by members of lipoproteins in HCV entry, replication and virion production.

Hepatitis viruses exploitation of host DNA methyltransferases functions

Hepatitis B virus (HBV), hepatitis C virus (HCV) and Delta (HDV) infections are a global health burden. With different routes of infection and biology, HBV, HCV and HDV are capable to induce liver cirrhosis and cancer by impinging on epigenetic mechanisms altering host cell's pathways. In the present manuscript, we reviewed the published studies taking into account the relationship between the hepatitis viruses and the DNA methyltransferases proteins.

A Multiantigenic DNA Vaccine That Induces Broad Hepatitis C Virus-Specific T-Cell Responses in Mice

There are 3 to 4 million new hepatitis C virus (HCV) infections annually around the world, but no vaccine is available. Robust T-cell mediated responses are necessary for effective clearance of the virus, and DNA vaccines result in a cell-mediated bias. Adjuvants are often required for effective vaccination, but during natural lytic viral infections damage-associated molecular patterns (DAMPs) are released, which act as natural adjuvants. Hence, a vaccine that induces cell necrosis and releases DAMPs will result in cell-mediated immunity (CMI), similar to that resulting from natural lytic viral infection. We have generated a DNA vaccine with the ability to elicit strong CMI against the HCV nonstructural (NS) proteins (3, 4A, 4B, and 5B) by encoding a cytolytic protein, perforin (PRF), and the antigens on a single plasmid. We examined the efficacy of the vaccines in C57BL/6 mice, as determined by gamma interferon enzyme-linked immunosorbent spot assay, cell proliferation studies, and intracellular cytokine production. Initially, we showed that encoding the NS4A protein in a vaccine which encoded only NS3 reduced the immunogenicity of NS3, whereas including PRF increased NS3 immunogenicity. In contrast, the inclusion of NS4A increased the immunogenicity of the NS3, NS4B, andNS5B proteins, when encoded in a DNA vaccine that also encoded PRF. Finally, vaccines that also encoded PRF elicited similar levels of CMI against each protein after vaccination with DNA encoding NS3, NS4A, NS4B, and NS5B compared to mice vaccinated with DNA encoding only NS3 or NS4B/5B. Thus, we have developed a promising "multiantigen" vaccine that elicits robust CMI.

IMPORTANCE

Since their development, vaccines have reduced the global burden of disease. One strategy for vaccine development is to use commercially viable DNA technology, which has the potential to generate robust immune responses. Hepatitis C virus causes chronic liver infection and is a leading cause of liver cancer. To date, no vaccine is currently available, and treatment is costly and often results in side effects, limiting the number of patients who are treated. Despite recent advances in treatment, prevention remains the key to efficient control and elimination of this virus. Here, we describe a novel DNA vaccine against hepatitis C virus that is capable of inducing robust cell-mediated immune responses in mice and is a promising vaccine candidate for humans.

Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture

BACKGROUND

Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α)-based combination therapy in chronic hepatitis C virus (HCV) infection. Previously, we reported that free fatty acid (FFA)-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1), which is why the antiviral activity of IFN-α against HCV is impaired.

AIM

To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment.

METHOD

HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate) and unsaturated (oleate) long-chain free fatty acids (FFA). Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α) and Type III IFN (IFN-λ) was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA) in the FFA-treated HCV cell culture model was investigated.

RESULTS

FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ), which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture. Pharmacological inhibitors of lysosomal degradation, such as ammonium chloride and bafilomycin, prevented IFNAR1 degradation in FFA-treated HCV cell culture. Activators of chaperone-mediated autophagy, including 6-aminonicotinamide and nutrient starvation, decreased IFNAR1 levels in Huh-7.5 cells. Co-immunoprecipitation, colocalization and siRNA knockdown experiments revealed that IFNAR1 but not IFNLR1 interacts with HSC70 and LAMP2A, which are core components of chaperone-mediated autophagy (CMA).

CONCLUSION

Our study presents evidence indicating that chaperone-mediated autophagy targets IFNAR1 degradation in the lysosome in FFA-treated HCV cell culture. These results provide a mechanism for why HCV induced autophagy response selectively degrades type I but not the type III IFNAR1.

Hepatitis C virus molecular evolution: Transmission, disease progression and antiviral therapy

Hepatitis C virus (HCV) infection represents an important public health problem worldwide. Reduction of HCV morbidity and mortality is a current challenge owned to several viral and host factors. Virus molecular evolution plays an important role in HCV transmission, disease progression and therapy outcome. The high degree of genetic heterogeneity characteristic of HCV is a key element for the rapid adaptation of the intrahost viral population to different selection pressures (e.g., host immune responses and antiviral therapy). HCV molecular evolution is shaped by different mechanisms including a high mutation rate, genetic bottlenecks, genetic drift, recombination, temporal variations and compartmentalization. These evolutionary processes constantly rearrange the composition of the HCV intrahost population in a staging manner. Remarkable advances in the understanding of the molecular mechanism controlling HCV replication have facilitated the development of a plethora of direct-acting antiviral agents against HCV. As a result, superior sustained viral responses have been attained. The rapidly evolving field of anti-HCV therapy is expected to broad its landscape even further with newer, more potent antivirals, bringing us one step closer to the interferon-free era.

Selective inhibition of hepatitis C virus infection by hydroxyzine and benztropine

Hepatitis C virus (HCV) infection is a major biomedical problem worldwide as it causes severe liver disease in millions of humans around the world. Despite the recent approval of specific drugs targeting HCV replication to be used in combination with alpha interferon (IFN-α) and ribavirin, there is still an urgent need for pangenotypic, interferon-free therapies to fight this genetically diverse group of viruses. In this study, we used an unbiased screening cell culture assay to interrogate a chemical library of compounds approved for clinical use in humans. This system enables identifying nontoxic antiviral compounds targeting every aspect of the viral life cycle, be the target viral or cellular. The aim of this study was to identify drugs approved for other therapeutic applications in humans that could be effective components of combination therapies against HCV. As a result of this analysis, we identified 12 compounds with antiviral activity in cell culture, some of which had previously been identified as HCV inhibitors with antiviral activity in cell culture and had been shown to be effective in patients. We selected two novel HCV antivirals, hydroxyzine and benztropine, to characterize them by determining their specificity and genotype spectrum as well as by defining the step of the replication cycle targeted by these compounds. We found that both compounds effectively inhibited viral entry at a postbinding step of genotypes 1, 2, 3, and 4 without affecting entry of other viruses.

Unfolded protein response in hepatitis C virus infection

Hepatitis C virus (HCV) is a single-stranded, positive-sense RNA virus of clinical importance. The virus establishes a chronic infection and can progress from chronic hepatitis, steatosis to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The mechanisms of viral persistence and pathogenesis are poorly understood. Recently the unfolded protein response (UPR), a cellular homeostatic response to endoplasmic reticulum (ER) stress, has emerged to be a major contributing factor in many human diseases. It is also evident that viruses interact with the host UPR in many different ways and the outcome could be pro-viral, anti-viral or pathogenic, depending on the particular type of infection. Here we present evidence for the elicitation of chronic ER stress in HCV infection. We analyze the UPR signaling pathways involved in HCV infection, the various levels of UPR regulation by different viral proteins and finally, we propose several mechanisms by which the virus provokes the UPR.

Epithelial-mesenchymal transition: molecular pathways of hepatitis viruses-induced hepatocellular carcinoma progression

Hepatocellular carcinoma is the fifth most common tumor and the third cause of death for cancer in the world. Among the main causative agents of this tumor is the chronic infection by hepatitis viruses B and C, which establish a context of chronic inflammation degenerating in fibrosis, cirrhosis, and, finally, cancer. Recent findings, however, indicate that hepatitis viruses are not only responsible for cancer onset but also for its progression towards metastasis. Indeed, they are able to promote epithelial-mesenchymal transition, a process of cellular reprogramming underlying tumor spread. In this manuscript, we review the currently known molecular mechanisms by which hepatitis viruses induce epithelial-mesenchymal transition and, thus, hepatocellular carcinoma progression.

Hepatitis C virus dysregulates glucose homeostasis by a dual mechanism involving induction of PGC1α and dephosphorylation of FoxO1

The maintenance of glucose homeostasis is a complex process in which the insulin signalling pathway plays a major role. Disruption of insulin-regulated glucose homeostasis is frequently observed in chronic hepatitis C (CHC) infection and might potentially contribute to type 2 diabetes mellitus (T2DM) development. Presently, the mechanism that links HCV infection to insulin resistance remains unclear. Previously, we have reported that HCV protein expression in HCV transgenic mice (B6HCV) leads to an overexpression of protein phosphatase 2A (PP2A) through an ER stress response. In the present work, we describe an association of FoxO1 hypophosphorylation and upregulation of both PGC-1α and G6Pase to phenotypic hyperglycaemia and insulin resistance in B6HCV mice. In vitro, we observed that PGC1α is concomitantly induced with PP2A. Moreover, we show that the enhanced PP2A expression is sufficient to inhibit insulin-induced FoxO1 phosphorylation via blockade of insulin-mediated Akt activation or/and through direct association and dephosphorylation of pS-FoxO1. Consequently, we found that the gluconeogenic gene glucose-6-phosphatase is upregulated. These observations were confirmed in liver biopsies obtained from CHC patients. In summary, our results show that HCV-mediated upregulation of PP2A catalytic subunit alters signalling pathways that control hepatic glucose homeostasis by inhibiting Akt and dephosphorylation of FoxO1.

Exploitation of host clock gene machinery by hepatitis viruses B and C

Many aspects of cellular physiology display circadian (approximately 24-h) rhythms. Dysfunction of the circadian clock molecular circuitry is associated with human health derangements, including neurodegeneration, increased risk of cancer, cardiovascular diseases and the metabolic syndrome. Viruses triggering hepatitis depend tightly on the host cell synthesis machinery for their own replication, survival and spreading. Recent evidences support a link between the circadian clock circuitry and viruses’ biological cycle within host cells. Currently, in vitro models for chronobiological studies of cells infected with viruses need to be implemented. The establishment of such in vitro models would be helpful to better understand the link between the clock gene machinery and viral replication/viral persistence in order to develop specifically targeted therapeutic regimens. Here we review the recent literature dealing with the interplay between hepatitis B and C viruses and clock genes.

Affinity analysis of differentially expressed genes in hepatocytes expressing HCV core genotype 1b or 3a

Chronic hepatitis C patients display many genotype-specific clinical features of HCV infection. The core proteins encoded by different genotypes dysregulate numerous sets of distinct host genes. In this study we tested the hypothesis that HCV core proteins 1b and 3a would actually act on a limited number of independent cellular players, as well as on several functionally linked gene products. Structural and functional tests identified a core set of host genes dysregulated by HCV core genotypes 1b and 3a. The core proteins of HCV genotypes 1b and 3a target specifically limited sets of functionally related gene products, which may be responsible for the variations in the clinical spectra associated with HCV infection.

Predictors of alcohol use among rural drug users after disclosure of hepatitis C virus status

OBJECTIVE

Alcohol consumption dramatically increases the risk of liver damage among those with hepatitis C virus (HCV) infection, yet the impact of HCV status disclosure and standard informational counseling on alcohol use among rural drug users remains poorly understood.

METHOD

In this prospective study, 503 rural Appalachian drug users were recruited using respondent-driven sampling. Participants were tested for HCV antibodies, and data on sociodemographic characteristics, lifetime and past-30-day drug and alcohol use, and psychiatric disorders were collected by interviewer-administered questionnaires. A total of 470 participants returned after 6 months for follow-up; however,4 of those had no history of alcohol use, thus leaving a final sample size of 466. Multivariate negative binomial regression was used to determine the effect of disclosure of HCV status and posttest counseling on alcohol consumption at follow-up.

RESULTS

Despite an overall decrease in drinking frequency in the cohort, those who were HCV-positive were drinking at a frequency similar to their HCV-negative counterparts at follow-up, despite posttest counseling informing them of the risks of alcohol use with an HCV diagnosis (adjusted incidence rate ratio = 1.07, 95% CI [0.72, 1.61]). Significant predictors of increased days of alcohol use after 6 months included baseline alcohol use, baseline marijuana use, and meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for antisocial personality disorder. Those using OxyContin at baseline had significantly fewer days of alcohol use at follow-up.

CONCLUSIONS

HCV status disclosure and standard informational counseling alone do not curtail drinking among HCV-positive drug users in the rural setting. Targeted interventions with regard to alcohol use are warranted in order to mitigate the damage of the HCV epidemic.

Mutual antagonism between circadian protein period 2 and hepatitis C virus replication in hepatocytes

BACKGROUND

Hepatitis C virus (HCV) infects approximately 3% of the world population and is the leading cause of liver disease, impacting hepatocyte metabolism, depending on virus genotype. Hepatic metabolic functions show rhythmic fluctuations with 24-h periodicity (circadian), driven by molecular clockworks ticking through translational-transcriptional feedback loops, operated by a set of genes, called clock genes, encoding circadian proteins. Disruption of biologic clocks is implicated in a variety of disorders including fatty liver disease, obesity and diabetes. The relation between HCV replication and the circadian clock is unknown.

METHODS

We investigated the relationship between HCV core infection and viral replication and the expression of clock genes (Rev-Erbα, Rorα, ARNTL, ARNTL2, CLOCK, PER1, PER2, PER3, CRY1 and CRY2) in two cellular models, the Huh-7 cells transiently expressing the HCV core protein genotypes 1b or 3a, and the OR6 cells stably harboring the full-length hepatitis C genotype 1b replicon, and in human liver biopsies, using qRT-PCR, immunoblotting, luciferase assays and immunohistochemistry.

RESULTS

In Huh-7 cells expressing the HCV core protein genotype 1b, but not 3a, and in OR6 cells, transcript and protein levels of PER2 and CRY2 were downregulated. Overexpression of PER2 led to a consistent decrease in HCV RNA replicating levels and restoration of altered expression pattern of a subset of interferon stimulated genes (ISGs) in OR6 cells. Furthermore, in liver biopsies from HCV genotype 1b infected patients, PER2 was markedly localized to the nucleus, consistent with an auto-inhibitory transcriptional feedback loop.

CONCLUSIONS

HCV can modulate hepatic clock gene machinery, and the circadian protein PER2 counteracts viral replication. Further understanding of circadian regulation of HCV replication and rhythmic patterns of host-hosted relationship may improve the effectiveness of HCV antiviral therapy. This would extend to hepatic viral infections the current spectrum of chronotherapies, implemented to treat metabolic, immune related and neoplastic disease.

Mutations in different regions of the genome of hepatitis C virus genotype 1b and association with response to interferon therapy

The aim of this study was to investigate the association of mutations in the E2/NS1 [hypervariable regions 1 and 2 (HVR1 and HVR2)] and NS5A regions of the hepatitis C virus (HCV) genome and the effectiveness of interferon (IFN) therapy, and assess whether the degree of heterogeneity of HCV quasispecies predicts response to IFN treatment. Fourteen patients infected with HCV genotype 1b (HCV-1b) who were treated with pegylated IFN-α-2a and ribavirin for 24 weeks, were studied. E2/NS1 and NS5A gene segments were amplified by reverse-transcription polymerase chain reaction. HCV quasispecies heterogeneity in the E2/NS1 region was determined by cloning and sequencing. Mutations in the NS5A region were detected by direct sequencing. The heterogeneity of HCV quasispecies in the HVR1 was significantly greater in the non-responder group than in the responder group, but was not significant for HVR2 or NS5A. The correlation between mutations in IFN sensitivity-determining region (ISDR, NS5A2209-2248) and IFN sensitivity could not be supported. The degree of quasispecies heterogeneity in HVR1, but not in HVR2 and NS5A, may be predictive of response to IFN therapy. An ISDR may not apply to patients infected with HCV-1b.

PPARs Signaling and Cancer in the Gastrointestinal System

Nowadays, the study of the peroxisome proliferators activated receptors (PPARs) as potential targets for cancer prevention and therapy has gained a strong interest. From a biological point of view, the overall responsibility of PPARs in cancer development and progression is still controversial since several studies report both antiproliferative and tumor-promoting actions for these signaling molecules in human cancer cells and animal models. In this paper, we discuss PPARs functions in the context of different types of gastrointestinal cancer.

DNA methyltransferases 1 and 3b expression in Huh-7 cells expressing HCV core protein of different genotypes

BACKGROUND

Hepatitis C virus infects ~3% of the population and it is a risk factor for hepatocarcinogenesis. The epigenetic mechanisms of HCV-induced hepatocyte transformation towards malignancy in this context are unclear.

AIMS

The purpose of this study was to evaluate the effect of HCV core proteins of different genotypes on DNA methyltransferases (DNMTs) induction.

MATERIALS/METHODS

We investigated DNMT1, DNMT3b and E-Cadherin (CDH1) mRNA and protein expression levels in an in vitro model of Huh-7 cells expressing the HCV core protein of different genotypes: 1b, 2a, 3a, 4h and 5a.

RESULTS

We found that both mRNA and protein expression levels of DNMT1 and 3b were upregulated in genotype 1b HCV core expressing cells as compared to control cells. DNMT3b mRNA levels did not change in genotypes 2a, 3a, 4h and 5a, but were upregulated at the protein level by genotype 1b, 2a, 3a. CDH1 mRNA expression was downregulated only in genotype 1b, whereas its protein expression resulted in downregulation by the HCV core of genotypes 1b, 2a and 3a. Conversely, no significant changes were observed for DNMTs and CDH1 investigated in Huh-7 cells expressing the genotypes 4h and 5a. Furthermore, we present evidence that HCV core 1b protein expression induces DNMTs overexpression through STAT3 protein as demonstrated by NSC74859 treatment. Moreover, SIRT1 inhibition affected DNMT1 and 3b expression only in HCV core protein genotype 1b expressing cells as demonstrated by treatment with its inhibitor sirtinol.

CONCLUSIONS

Our findings suggest that HCV core protein could play a role in HCC development at least in part by altering DNMTs expression.

Differentially expressed microRNAs in Huh-7 cells expressing HCV core genotypes 3a or 1b: potential functions and downstream pathways

microRNA (miRNA) dysfunction is believed to play important roles in human diseases, including viral infectious diseases. Hepatitis C virus (HCV) infection promotes the development of steatosis, cirrhosis and hepatocellular carcinoma, which is genotype-specific. In order to characterize the miRNA expression profile of Huh-7 cells expressing the HCV core 3a vs. 1b, microarrays and real-time PCR were performed. Consequently, 16 miRNAs (5 miRNAs upregulated and 11 miRNAs downregulated) were found to be dysregulated. In addition, we generated the predicted and validated targets of the differentially expressed miRNAs and explored potential downstream function categories and pathways of target genes using databases of Gene Ontology (GO) and PANTHER and the database for annotation, visualization and integrated discovery (David). The computational results indicated that the dysregulated miRNAs might perform the functions of cellular metabolism and cellular growth. Finally, these biological effects were preliminarily validated. This study identifies a specific miRNA expression profile in cells expressing HCV core proteins of different genotypes (genotype 3a and 1b), which may account for the variable pathophysiological manifestation associated with HCV infection.

Oxidative stress, endogenous antioxidants, alcohol, and hepatitis C: pathogenic interactions and therapeutic considerations

Hepatitis C virus (HCV) is a blood-borne pathogen that was identified as an etiologic agent of non-A, non-B hepatitis in 1989. HCV is estimated to have infected at least 170 million people worldwide. The majority of patients infected with HCV do not clear the virus and become chronically infected, and chronic HCV infection increases the risk for hepatic steatosis, cirrhosis, and hepatocellular carcinoma. HCV induces oxidative/nitrosative stress from multiple sources, including inducible nitric oxide synthase, the mitochondrial electron transport chain, hepatocyte NAD(P)H oxidases, and inflammation, while decreasing glutathione. The cumulative oxidative burden is likely to promote both hepatic and extrahepatic conditions precipitated by HCV through a combination of local and more distal effects of reactive species, and clinical, animal, and in vitro studies strongly point to a role of oxidative/nitrosative stress in HCV-induced pathogenesis. Oxidative stress and hepatopathogenesis induced by HCV are exacerbated by even low doses of alcohol. Alcohol and reactive species may have other effects on hepatitis C patients such as modulation of the host immune system, viral replication, and positive selection of HCV sequence variants that contribute to antiviral resistance. This review summarizes the current understanding of redox interactions of HCV, outlining key experimental findings, directions for future research, and potential applications to therapy.