Pathogenesis Of Hepatitis C Virus Infection Research Articles

A juggernaut of innate & adaptive immune cells in chronic hepatitis C.

Hepatitis C virus (HCV) is a small positive-sense, single-stranded RNA virus, the causal organism for chronic hepatitis. Chronic hepatitis leads to inflammation of liver, causing cirrhosis, fibrosis and steatosis, which may ultimately lead to liver cancer in a few cases. Innate and adaptive immune responses play an important role in the pathogenesis of HCV infection, thus acting as an important component in deciding the fate of the disease. Numerous studies have indicated that the derangement of these immune responses results in the persistence of infection leading to chronic state of the disease. Interactions between virus and host immune system generally result in the elimination of virus, but as the virus evolves with different evading mechanisms, it makes environment favourable for its survival and replication. It has been reported that HCV impairs the immune system by functional modulation of the cells of innate as well as adaptive immune responses, resulting in chronic state of the disease, influencing the response to antiviral therapy in these patients. These defects in the immune system lead to suboptimal immune responses and therefore, impaired effector functions. This review highlights the involvement or association of different immune cells such as natural killer cells, B cells, dendritic cells and T cells in HCV infection and how the virus plays a role in manipulating certain regulatory mechanisms to make these cells dysfunctional for its own persistence and survival.

The Role of Micronutrients in the Infection and Subsequent Response to Hepatitis C Virus.

Micronutrient deficiencies develop for a variety of reasons, whether geographic, socioeconomic, nutritional, or as a result of disease pathologies such as chronic viral infection. As micronutrients are essential for a strong immune response, deficiencies can significantly dampen both the innate and the adaptive arms of antiviral immunity. The innate immune response in particular is crucial to protect against hepatitis C virus (HCV), a hepatotropic virus that maintains chronic infection in up to 80% of individuals if left untreated. While many micronutrients are required for HCV replication, an overlapping group of micronutrients are also necessary to enact a potent immune response. As the liver is responsible for the storage and metabolism of many micronutrients, HCV persistence can influence the micronutrients’ steady state to benefit viral persistence both directly and by weakening the antiviral response. This review will focus on common micronutrients such as zinc, iron, copper, selenium, vitamin A, vitamin B12, vitamin D and vitamin E. We will explore their role in the pathogenesis of HCV infection and in the response to antiviral therapy. While chronic hepatitis C virus infection drives deficiencies in micronutrients such as zinc, selenium, vitamin A and B12, it also stimulates copper and iron excess; these micronutrients influence antioxidant, inflammatory and immune responses to HCV.

Alcohol-induced autophagy via upregulation of PIASy promotes HCV replication in human hepatoma cells

Both alcohol and hepatitis C virus (HCV) infection could induce cellular autophagy in liver cells, which is considered to be essential for productive HCV replication. However, whether alcohol-induced autophagy is involved in the pathogenesis of HCV infection is still poorly understood. Alcohol treatment could induce autophagy in Huh7 cells (a hepatoma cell line that supports HCV JFH-1 replication), evidenced by the increase of LC3B-II levels, the conversion of LC3B-I to LC3B-II, and the formation of GFP-LC3 puncta as well as the decrease of p62 level in alcohol-treated cells compared with control cells. Alcohol treatment also significantly increased PIASy (a member of the PIAS family) expression, which can act as a SUMO (small ubiquitin-like modifier protein) E3 ligase to regulate a broader range of cellular processes including autophagy. Overexpression or the silencing expression of PIASy in alcohol-treated Huh7 cells could increase or decrease autophagic activation caused by alcohol treatment, respectively, and thus affect HCV replication correspondingly. In the absence of alcohol, overexpression or silencing expression of PIASy increase or decrease the level of cellular autophagy, judged by the changes of LC3B-II and p62 levels in the presence or absence of chloroquine (CQ), a lysosome inhibitor. More importantly, in the presence of 3-methyladenine (3-MA), an inhibitor in the early stage of autophagy, the effects of overexpression or silencing expression of PIASy on HCV replication were largely blocked. Furthermore, PIASy could selectively drive the accumulation of SUMO1-conjugated proteins, along with upregulation of the expression of several important autophagy factors, including ATG7 and ATG5–ATG12. In conclusion, alcohol promotes HCV replication through activation of autophagy in Huh7 cells, which partly attributes to its induction of PIASy expression. PIASy-enhanced accumulation of SUMO1-conjugated proteins may contribute to its inducing effect of autophagy. Our findings provide a novel mechanism for the action of alcohol-promoting HCV replication in the context of cellular autophagy.

Nonstructural Protein 5A Impairs DNA Damage Repair: Implications for Hepatitis C Virus-Mediated Hepatocarcinogenesis.

RAD51-associated protein 1 (RAD51AP1) is a member of the multiprotein complexes postulated to carry out RAD51-mediated homologous recombination and DNA repair in mammalian cells. In the present study, we showed that hepatitis C virus (HCV) NS5A directly bound RAD51AP1 and increased the protein level of RAD51AP1 through modulation of the ubiquitin-proteasome pathway. We also demonstrated that RAD51AP1 protein levels were increased in the liver tissues of HCV-infected patients and NS5A-transgenic mice. Importantly, NS5A impaired DNA repair by disrupting the RAD51/RAD51AP1/UAF1 complex and rendered HCV-infected cells more sensitive to DNA damage. Silencing of RAD51AP1 expression resulted in a decrease of viral propagation. We further demonstrated that RAD51AP1 was involved in the assembly step of the HCV life cycle by protecting viral RNA. These data suggest that HCV exploits RAD51AP1 to promote viral propagation and thus that host DNA repair is compromised in HCV-infected cells. Overall, our findings provide mechanistic insight into the pathogenesis of HCV infection.IMPORTANCE Chronic infection with HCV is the leading cause of hepatocellular carcinoma (HCC). However, the molecular mechanisms underlying HCV-induced HCC are not fully understood. Here we demonstrate that the HCV NS5A protein physically interacts with RAD51AP1 and increases the RAD51AP1 protein level through modulation of the ubiquitin-proteasome pathway. HCV coopts host RAD51AP1 to protect viral RNA at an assembly step of the HCV life cycle. Note that the RAD51 protein accumulates in the cytoplasm of HCV-infected cells, and thus the RAD51/RAD51AP1/UAF1-mediated DNA damage repair system in the nucleus is compromised in HCV-infected cells. Our data may provide new insight into the molecular mechanisms of HCV-induced pathogenesis.

Autophagy, apoptosis, vitamin D, and vitamin D receptor in hepatocellular carcinoma associated with hepatitis C virus.

The aims of this study were to investigate the interplay between autophagy and apoptosis and to investigate the association between both of autophagy and apoptosis and vitamin D and its receptor in hepatitis C virus (HCV) viral infection and its implication in the progression into hepatocellular carcinoma (HCC).A cross-sectional study where serum levels of microtubule-associated protein 1A/1B-light chain 3 (LC3); marker of autophagy, caspase-3; marker of apoptosis, vitamin D3 and vitamin D receptor (VDR) were measured in healthy subjects as well as HCV and HCV-HCC patients using enzyme-linked immunosorbent assay technique.Collectively, the liver profile revealed hepatic dysfunctions in HCV patients with or without HCC. A significant reduction in the serum concentration levels LC3 and caspase-3 were observed referring to the down regulation of autophagy and host-mediated apoptosis in HCV patients with or without HCC. Deficiency of vitamin D and decreased levels of its receptor were observed in HCV and HCV-HCC patients.The perturbation in vitamin D/VDR axis, which modulates both of autophagy and apoptosis in HCV infection, may point out to its involvement and implication in the pathogenesis of HCV infection and the development of HCV-related HCC. Therefore, supplementation with vitamin D may not be the only solution to restore the vital biological functions of vitamin D but VDR-targeted therapy may be of great importance in this respect.

Structural Changes In Cells Imaged by Soft X-ray Cryo-Tomography During Hepatitis C Virus Infection.

Chronic hepatitis C virus (HCV) infection causes severe liver disease in millions of humans worldwide. Pathogenesis of HCV infection is strongly driven by a deficient immune response of the host, although intersection of different aspects of the virus life cycle with cellular homeostasis is emerging as an important player in the pathogenesis and progression of the disease. Cryo soft X-ray tomography (cryo-SXT) was performed to investigate the ultrastructural alterations induced by the interference of HCV replication with cellular homeostasis. Native, whole cell, three-dimensional (3D) maps were obtained in HCV replicon-harboring cells and in a surrogate model of HCV infection. Tomograms from HCV-replicating cells show blind-ended endoplasmic reticulum tubules with pseudospherical extrusions and marked alterations of mitochondrial morphology that correlated spatially with the presence of endoplasmic reticulum alterations, suggesting a short-range influence of the viral machinery on mitochondrial homeostasis. Both mitochondrial and endoplasmic reticulum alterations could be reverted by a combination of sofosbuvir/daclatasvir, which are clinically approved direct-acting antivirals for the treatment of chronic HCV infection. In addition to providing structural insight into cellular aspects of HCV pathogenesis, our study illustrates how cryo-SXT is a powerful 3D wide-field imaging tool for the assessment and understanding of complex cellular processes in a setting of near-native whole hydrated cells. Our results also constitute a proof of concept for the use of cryo-SXT as a platform that enables determining the potential impact of candidate compounds on the ultrastructure of the cell that may assist drug development at a preclinical level.

Hepatic expression of proteasome subunit alpha type-6 is upregulated during viral hepatitis and putatively regulates the expression of ISG15 ubiquitin-like modifier, a proviral host gene in hepatitis C virus infection.

The interferon-stimulated gene 15 (ISG15) plays an important role in the pathogenesis of hepatitis C virus (HCV) infection. ISG15-regulated proteins have previously been identified that putatively affect this proviral interaction. The present observational study aimed to elucidate the relation between ISG15 and these host factors during HCV infection. Transcriptomic and proteomic analyses were performed using liver samples of HCV-infected (n = 54) and uninfected (n = 10) or HBV-infected controls (n = 23). Primary human hepatocytes (PHH) were treated with Toll-like receptor ligands, interferons and kinase inhibitors. Expression of ISG15 and proteasome subunit alpha type-6 (PSMA6) was suppressed in subgenomic HCV replicon cell lines using specific siRNAs. Comparison of hepatic expression patterns revealed significantly increased signals for ISG15, IFIT1, HNRNPK and PSMA6 on the protein level as well as ISG15, IFIT1 and PSMA6 on the mRNA level in HCV-infected patients. In contrast to interferon-stimulated genes, PSMA6 expression occurred independent of HCV load and genotype. In PHH, the expression of ISG15 and PSMA6 was distinctly induced by poly(I:C), depending on IRF3 activation or PI3K/AKT signalling, respectively. Suppression of PSMA6 in HCV replicon cells led to significant induction of ISG15 expression, thus combined knock-down of both genes abrogated the antiviral effect induced by the separate suppression of ISG15. These data indicate that hepatic expression of PSMA6, which is upregulated during viral hepatitis, likely depends on TLR3 activation. PSMA6 affects the expression of immunoregulatory ISG15, a proviral factor in the pathogenesis of HCV infection. Therefore, the proteasome might be involved in the enigmatic interaction between ISG15 and HCV.

Chronic hepatitis C virus infection: Serum biomarkers in predicting liver damage.

Currently, a major clinical challenge in the management of the increasing number of hepatitis C virus (HCV) infected patients is determining the best means for evaluating liver impairment. Prognosis and treatment of chronic hepatitis C (CHC) are partly dependent on the assessment of histological activity, namely cell necrosis and inflammation, and the degree of liver fibrosis. These parameters can be provided by liver biopsy; however, in addition to the risks related to an invasive procedure, liver biopsy has been associated with sampling error mostly due to suboptimal biopsy size. To avoid these pitfalls, several markers have been proposed as non-invasive alternatives for the diagnosis of liver damage. Distinct approaches among the currently available non-invasive methods are (1) the physical ones based on imaging techniques; and (2) the biological ones based on serum biomarkers. In this review, we discuss these approaches with special focus on currently available non-invasive serum markers. We will discuss: (1) class I serum biomarkers individually and as combined panels, particularly those that mirror the metabolism of liver extracellular matrix turnover and/or fibrogenic cell changes; (2) class II biomarkers that are indirect serum markers and are based on the evaluation of common functional alterations in the liver; and (3) biomarkers of liver cell death, since hepatocyte apoptosis plays a significant role in the pathogenesis of HCV infection. We highlight in this review the evidence behind the use of these markers and assess the diagnostic accuracy as well as advantages, limitations, and application in clinical practice of each test for predicting liver damage in CHC.

Hepatic apoptotic markers are not predictors for the virological response to interferon-based therapy in chronic hepatitis C patients.

Chronic hepatitis C virus (HCV) infection is a major health problem worldwide. The majority of cases involving HCV infection develop into chronic hepatitis because of a failure to develop an effective immune response. Apoptosis of the hepatocytes plays a significant role in the pathogenesis of HCV infection: the interaction between the Fas antigen on hepatocytes and the Fas ligand on T cells corresponds to the main mechanism for hepatocyte damage. Interferon (IFN)-α has antiviral, immunoregulatory, and antiproliferative properties, and apoptosis seems to be a critical event in the action mechanisms of both IFNs. In this study, we aimed to detect any relationship between apoptotic markers in the liver and the response to the treatment. The study included 180 chronic HCV patients treated with IFN and ribavirin in four centers. Apoptotic markers (Fas, Fas ligand, Fas-associated death domain, caspases 3, 8, and 9, and in-situ apoptosis) were studied in the liver. The age, sex of the patients, response to therapy, ALT level, viral load, and genotype were recorded. The results of the study showed that the histological activity index and fibrosis correlated with CD95 staining density, caspase-8 intensiveness, and portal and parenchymal Fas ligand scores. The apoptotic parameters of the responsive cases were not significantly different from those of the unresponsive cases. The apoptotic parameters studied in liver tissue are associated with inflammation and fibrosis; however, these parameters may not predict response to treatment.

Hepatitis C Virus Nonstructural Protein 5A Inhibits MG132-Induced Apoptosis of Hepatocytes in Line with NF-κB-Nuclear Translocation.

BackgroundHepatitis C virus (HCV) infection is one of the major causes of cirrhosis and hepatocellular carcinoma. HCV nonstructural protein 5A (NS5A) is an attractive antiviral target and plays an important role in HCV replication as well as hepatocarcinogenesis. The aim of this study was to assess the effect of HCV NS5A protein in the abrogation of apoptotic cell death induced by the proteasome inhibitor MG132.MethodsApoptotic responses to MG132 and the expression of molecules involved in NF-κB signaling pathways in human hepatocytes were investigated with or without the expression of HCV NS5A.ResultsHCV NS5A protected HepG2 cells against MG132-induced apoptosis, in line with NF-κB-nuclear translocation. A similar NF-κB-nuclear translocation was observed in Huh7 cells infected with HCV JFH1. In agreement with this, after treatment with MG132, HCV NS5A could elevate the transcription of several NF-κB target genes such as BCL2 and BCLXL to inhibit MG132-induced apoptosis in hepatocytes. HCV HCV NS5A also enhanced phosphorylation of IκBα. Consistent with a conferred prosurvival advantage, HCV NS5A reduced MG132-induced poly(adenosine diphosphate-ribose) polymerase cleavage.ConclusionsHCV NS5A expression enhances phosphorylation of IκBα, liberates NF-κB for nuclear translocation and downregulates MG132-induced apoptotic pathways in human hepatocytes. It is possible that the disruption of proteasome-associated apoptosis plays a role in the pathogenesis of HCV infection.

Low-density lipoprotein receptor on peripheral lymphocytes as a candidate receptor for hepatitis C virus

Objective The aim of this work was to assess the role of low-density lipoprotein receptor ( LDLR ) on peripheral lymphocytes as a candidate receptor for hepatitis C virus (HCV) in patients with chronic HCV both without interferon treatment and after interferon treatment in comparison with a control group. Background HCV is one of the most prevalent infectious diseases in Egypt. It is considered the main cause of hepatic morbidity in Egypt, with progression to chronic liver disease, cirrhosis, and hepatocellular carcinoma. Pioneering studies have reported the involvement of the LDLR in the cellular entry of HCV. LDLR was found to play a role in the pathogenesis of HCV infection. Materials and methods Peripheral blood lymphocytes were isolated from 40 patients with chronic HCV without interferon treatment and 20 patients with HCV after interferon treatment. Quantification of LDLR expression was performed by flow cytometry and the results were compared with those of 20 normal volunteers as a control group. Results There was a significant difference between the mean ± SD of LDLR % between HCV cases (89.08 ± 4.89), post-interferon treatment cases (57.45 ± 4.72), and the control group (54.69 ± 8.48). There was a significant positive correlation between LDLR %, LDLR mean fluorescence intensity, and viral load. Conclusion There was a significant positive correlation between the amount of LDLR expression on peripheral lymphocytes and viral load as quantified by PCR. This indicates the involvement of LDLR in the pathogenesis of HCV infections.

Hepatitis C virus nonstructural protein 5A inhibits thapsigargin-induced apoptosis.

BackgroundWe previously reported that the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) down-regulates TLR4 signaling and lipopolysaccharide-induced apoptosis of hepatocytes. There have been several reports regarding the association between HCV infection and endoplasmic reticulum (ER) stress. Here, we examined the regulation of HCV NS5A on the apoptosis of hepatocytes induced by thapsigargin, an inducer of ER stress.MethodsThe apoptotic response to thapsigargin and the expression of molecules involved in human hepatocyte apoptotic pathways were examined in the presence or absence of HCV NS5A expression.ResultsHCV JFH1 infection induced ER stress in the Huh7 cell line. HCV NS5A protected HepG2 cells against thapsigargin-induced apoptosis, the effect of which was linked to the enhanced expression of the 78-kDa glucose-regulated protein/immunoglobulin heavy-chain binding protein (GRP78). Consistent with a conferred pro-survival advantage, HCV NS5A reduced poly(adenosine diphosphate-ribose) polymerase cleavage and activation of caspases-3, -7 and -9, and Bax expression, while increasing the expressions of the anti-apoptotic molecules XIAP and c-FLIP. HCV NS5A weakly interacts with GRP78 and enhances GRP78 expression in hepatocytes.ConclusionHCV NS5A enhances GRP78 expression, resulting in the inhibition of apoptotic properties, and inhibits thapsigargin-induced apoptotic pathways in human hepatocytes, suggesting that disruption of ER stress-mediated apoptosis may have a role in the pathogenesis of HCV infection. Thus, HCV NS5A might engender the survival of HCV-infected hepatocytes contributing to the establishment of persistent infection.

THE ROLE OF CYTOKINE GENES POLYMORPHISM IN HEPATITIS C VIRUS INFECTION

Abstract. The outcome of hepatitis C virus (HCV) infection depends on the immune response caused by the host genetic factors. Cytokines are key mediators of inflammation and development of specific immunity, which is responsible for the elimination of HCV. It has been found that the polymorphisms in several cytokine genes play role in human susceptibility to HCV infection, determine its differences in response to HCV and treatment-induced HCV clearance. This review summarizes the results of studies on the single-nucleotide polymorphisms of cytokine genes that complete our knowledge of the pathogenesis of HCV infection.

Hepatitis C Virus NS2 Protein Inhibits DNA Damage Pathway by Sequestering p53 to the Cytoplasm

Chronic hepatitis C virus (HCV) infection is an important cause of morbidity and mortality globally, and often leads to end-stage liver disease. The DNA damage checkpoint pathway induces cell cycle arrest for repairing DNA in response to DNA damage. HCV infection has been involved in this pathway. In this study, we assess the effects of HCV NS2 on DNA damage checkpoint pathway. We have observed that HCV NS2 induces ataxia-telangiectasia mutated checkpoint pathway by inducing Chk2, however, fails to activate the subsequent downstream pathway. Further study suggested that p53 is retained in the cytoplasm of HCV NS2 expressing cells, and p21 expression is not enhanced. We further observed that HCV NS2 expressing cells induce cyclin E expression and promote cell growth. Together these results suggested that HCV NS2 inhibits DNA damage response by altering the localization of p53, and may play a role in the pathogenesis of HCV infection.

Imaging of hepatitis C virus infection in liver grafts after liver transplantation

The detection of native hepatitis C virus (HCV) antigens in liver tissue may be relevant to diagnostic purposes and to better understand the pathogenesis of HCV infection. The aim of our study was to characterize HCV antigens in liver grafts. We selected 32 liver transplant (LT) recipients with recurrent hepatitis C. HCV core and NS5A antigens were detected in formalin-fixed, paraffin-embedded (FFPE) liver biopsies obtained immediately after graft reperfusion (negative controls), during the acute phase of HCV infection (1-6 months) and during follow-up (7-74 months) after LT. Viral antigens were assessed by immunohistochemistry and confocal microscopy. All reperfusion biopsies were negative for both antigens. Core protein was detected in 75% and 33% of acute phase and follow-up biopsies, respectively. HCV antigens were not detected in any of the 10 samples from patients who cleared HCV after antiviral treatment. Immunostaining was hepatocellular, with a granular cytoplasmic pattern and a wide spectrum of intensity. We found a significant association between viral load and the presence of HCV core-positive hepatocytes (p=0.004). NS5A colocalized strongly with core (66%) and adipophilin (36%), supporting the localization of core and NS5A around lipid droplets. A detailed three-dimensional analysis showed that NS5A surrounded the core and adipophilin-positive areas. HCV antigens can be detected in FFPE liver biopsies by immunohistochemistry. The in vivo colocalization of core and NS5A proteins around the lipid droplets supports that the latter may play a role in virus particle production, similar to what reported in vitro.

CD40 inhibits replication of hepatitis C virus in primary human hepatocytes by c-jun N terminal kinase activation independent from the interferon pathway

CD40, a member of the tumor necrosis factor receptor family, and its ligand, CD40L (CD154), are important regulators of the antiviral immune response. CD40L is up-regulated on lymphocytes and CD40 on hepatocytes during infection with hepatitis C virus (HCV); we investigated the role of CD40 signaling during HCV replication in hepatocytes. Viral replication was studied in primary human hepatocytes (PHH) and Huh7.5 cells using the infectious HCV Japanese fulminate hepatitis 1 isolate (JFH1) culture system, and in coculture with HCV antigen-specific CD8+ T cells. CD40L rapidly and transiently inhibits expression of the HCV nonstructural proteins NS3 and NS5A as well as HCV structural proteins core and E2 in Huh7.5 cells. Similarly, CD40L prevented replication of HCV in PHH, in synergy with interferon (IFN)-alpha. In Huh7.5 cells with replicating HCV, CD40L prevented production of infectious viral particles. When HCV antigen-specific CD8+ T cells were cocultured with HLA-A2-expressing Huh7 cells that had replicating virus, the T cells became activated, up-regulated CD40L, and inhibited HCV replication. Inhibition of CD40L partially prevented the antiviral activity of the CD8+ T cells. The antiviral effect of CD40L required activation of c-Jun N terminal kinases (JNK)1/2, but not induction of apoptosis or the JAK/STAT pathway that is necessary for the antiviral effects of IFNs. CD40 inhibits HCV replication by a novel, innate immune mechanism. This pathway might mediate viral clearance, and disruptions might be involved in the pathogenesis of HCV infection.

Ethanol facilitates hepatitis C virus replication via up-regulation of GW182 and heat shock protein 90 in human hepatoma cells

Alcohol use and hepatitis C virus (HCV) infection synergize to cause liver damage, and microRNA-122 (miR-122) appears to play a key role in this process. Argonaute 2 (Ago2), a key component of the RNA-induced silencing complex (RISC), has been shown to be important in modulating miR-122 function during HCV infection. However, GW182, a critical component of processing bodies (GW bodies) that is recruited by Ago2 to target messenger RNA (mRNA), has not been assessed in HCV infection. To characterize the role of GW182 in the pathogenesis of HCV infection, we determined its transcription and protein expression in an HCV J6/JFH1 culture system. Transcript and protein levels of GW182 as well as HCV RNA and protein expression increased with alcohol exposure. Specific silencing of mRNA expression by small interfering RNA against GW182 significantly decreased HCV RNA and protein expression. Overexpression of GW182 significantly increased HCV RNA and protein expression in HCV J6/JFH1 infected Huh7.5 cells. Furthermore, GW182 colocalized and coimmunoprecipitated with heat shock protein 90 (HSP90), which increased upon alcohol exposure with and without HCV infection and enhanced HCV gene expression. The use of an HSP90 inhibitor or knockdown of HSP90 decreased GW182 and miR-122 expression and significantly reduced HCV replication. Overall, our results suggest that GW182 protein that is linked to miR-122 biogenesis and HSP90, which has been shown to stabilize the RISC, are novel host proteins that regulate HCV infection during alcohol abuse.

Molecular Modeling and Interaction Studies of HCV Core Protein

HCV is a leading cause of liver disease and can lead to hepatocellular carcinoma and liver damage which in turn can cause death of patients. HCV is closely related to immune response especially inflammation suggesting that the immune response-related genes can serve as molecular targets for chemo-prevention and treatment of C-type HCC. This study was conducted to determine the 3D structures of immune responsive gene (CXCL6) that are up-regulated during Hepatitis C Virus (HCV) Infection and Hepatocellular Carcinoma (HCC) and HCV core protein.Furthermore, docking and interactions analysis of immune responsive gene with HCV core protein was performed to understand pathogenesis of HCV infection. Reliable 3D structures of both proteins were determined using comparative modeling approach. Docking of both proteins revealed functionally important residues i-e. Arg149, Arg39, Arg74 and Gln78 in HCV core protein and Leu44, Ala71, Ser76 and Pro97 in CXCL6. It can be concluded from the study that CXCL6 had potentially interacting residues with HCV core protein that can be helpful in finding clues to understand HCV pathogenesis and develop better therapeutic regimens.

Serum Profile of T Helper 1 and T Helper 2 Cytokines in Hepatitis C Virus Infected Patients

BackgroundT-helper (Th) lymphocyte cytokine production may be important in the immune pathogenesis of hepatitis C virus (HCV) infections. Th1 cytokines such as; interleukin-2 (IL-2), and interferon gamma (IFN-gamma) are necessary for host antiviral immune responses, while Th2 cytokines (IL-4, IL-10) can inhibit the development of these effector mechanisms.ObjectivesThe aim of the present study was to assess the serum profile of Th1 and Th2 cytokines in treated and non-treated HCV infected individuals.Patients and MethodsThis study was carried out in 63 HCV infected patients (31 under treatment and 32 untreated) and 32 matched HCV-sero negative healthy subjects. Serum samples were checked with an enzyme-linked immune sorbent assay (ELISA) for IL-2, IL-4, IL-10 and IFN-gamma.ResultsLevels of circulating IL-2, IL-4, IL-10 and IFN-gamma were significantly elevated in HCV patients versus normal controls (2 822.6 ± 1 259.92 vs. 950.8 ± 286.9 pg/mL; 1 987 ± 900.69 vs. 895.91 ± 332.33 pg/mL; 1 688.5 ± 1 405.1 vs. 519.03 ± 177.64 pg/mL and 1 501.9 ± 1 298 vs. 264.66 ± 71.59 pg/mL, respectively; P < 0.001). The serum levels of all cytokines were significantly lower in the patients under treatment than those of the untreated patients (P < 0.001).ConclusionsOn the basis of our data, the simultaneous increase of Th1 and Th2 related cytokines may indicate that both Thl and Th2 cytokines are involved in the pathogenesis of HCV infections. Moreover, this activated T-cell response in HCV infected patients may be regulated by treatment.

Role of Oxidative Stress in Hepatocarcinogenesis Induced by Hepatitis C Virus

Hepatitis C virus (HCV) easily establishes chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). During the progression of HCV infections, reactive oxygen species (ROS) are generated, and these ROS then induce significant DNA damage. The role of ROS in the pathogenesis of HCV infection is still not fully understood. Recently, we found that HCV induced the expression of 3β-hydroxysterol Δ24-reductase (DHCR24). We also found that a HCV responsive region is present in the 5′-flanking genomic promoter region of DHCR24 and the HCV responsive region was characterized as (−167/−140). Moreover, the transcription factor Sp1 was found to bind to this region in response to oxidative stress under the regulation of ataxia telangiectasia mutated (ATM) kinase. Overexpression of DHCR24 impaired p53 activity by suppression of acetylation and increased interaction with MDM2. This impairment of p53 suppressed the hydrogen peroxide-induced apoptotic response in hepatocytes. Thus, a target of oxidative stress in HCV infection is DHCR24 through Sp1, which suppresses apoptotic responses and increases tumorigenicity.