An overview of HCV molecular biology, replication and immune responses

Investigation into the Neuroprotective and Therapeutic Potential of Plant-Derived Chk2 Inhibitors

Nature provides us with a rich source of compounds with a wide range of applications, including the creation of innovative drugs. Despite advancements in chemically synthesized therapeutics, natural compounds are increasingly significant, especially in cancer treatment, a leading cause of death globally. One promising approach involves the use of natural inhibitors of checkpoint kinase 2 (Chk2), a critical regulator of DNA repair, cell cycle arrest, and apoptosis. Chk2's activation in response to DNA damage can lead to apoptosis or DNA repair, influencing glycolysis and mitochondrial function. In cancer therapy, inhibiting Chk2 can disrupt DNA repair and cell cycle progression, promoting cancer cell death and enhancing the efficacy of radiotherapy and chemotherapy. Additionally, Chk2 inhibitors can safeguard non-cancerous cells during these treatments by inhibiting p53-dependent apoptosis. Beyond oncology, Chk2 inhibition shows potential in treating hepatitis C virus (HCV) infections, as the virus relies on Chk2 for RNA replication in neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), in which DNA damage plays a crucial role. Plant-derived Chk2 inhibitors, such as artemetin, rhamnetin, and curcumin, offer a promising future for treating various diseases with potentially milder side effects and broader metabolic impacts compared to conventional therapies. The review aims to underscore the immense potential of natural Chk2 inhibitors in various therapeutic contexts, particularly in oncology and the treatment of other diseases involving DNA damage and repair mechanisms. These natural Chk2 inhibitors hold significant promise for revolutionizing the landscape of cancer treatment and other diseases. Further research into these compounds could lead to the development of innovative therapies that offer hope for the future with fewer side effects and enhanced efficacy.

Lectibodies as antivirals

Growing concerns regarding the emergence of highly transmissible viral diseases highlight the urgent need to expand the repertoire of antiviral therapeutics. For this reason, new strategies for neutralizing and inhibiting these viruses are necessary. A promising approach involves targeting the glycans present on the surfaces of enveloped viruses. Lectins, known for their ability to recognize specific carbohydrate molecules, offer the potential for glycan-targeted antiviral strategies. Indeed, numerous studies have reported the antiviral effects of various lectins of both endogenous and exogenous origins. However, many lectins in their natural forms, are not suitable for use as antiviral therapeutics due to toxicity, other unfavorable pharmacological effects, and/or unreliable manufacturing sources. Therefore, improvements are crucial for employing lectins as effective antiviral therapeutics. A novel approach to enhance lectins' suitability as pharmaceuticals could be the generation of recombinant lectin-Fc fusion proteins, termed "lectibodies." In this review, we discuss the scientific rationale behind lectin-based antiviral strategies and explore how lectibodies could facilitate the development of new antiviral therapeutics. We will also share our perspective on the potential of these molecules to transcend their potential use as antiviral agents.

Exploring the Impact of Different Inflammatory Cytokines on Hepatitis C Virus Infection

Hepatitis C virus (HCV) infection is a global health concern affecting millions worldwide. Chronic HCV infection often leads to liver inflammation and can progress to cirrhosis and hepatocellular carcinoma. Inflammatory cytokines are crucial in modulating the immune response during HCV infection. This review aims to investigate the impact of different inflammatory cytokines on HCV infection and associated immune responses. This review was conducted to identify relevant studies on the interplay between inflammatory cytokines and HCV infection. The analysis focused on the effects of key inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 (IL-1), and interferon-gamma (IFN-γ), on HCV replication, immune cell activation, and liver inflammation. The findings reveal that these inflammatory cytokines can significantly influence HCV infection and the subsequent immune response. TNF-α, IL-6, and IL-1 have been shown to enhance HCV replication, while IFN-γ exerts antiviral effects by inhibiting viral replication and promoting immune cell-mediated clearance of infected hepatocytes. Moreover, these cytokines contribute to the recruitment and activation of immune cells, such as natural killer cells, T cells, and macrophages, which play critical roles in controlling HCV infection. Understanding the precise mechanisms by which inflammatory cytokines impact HCV infection is crucial for developing more targeted therapeutic strategies. Modulating the levels or activity of specific cytokines may provide opportunities to attenuate HCV replication, reduce liver inflammation, and improve treatment outcomes. In conclusion, this review highlights the significance of inflammatory cytokines in influencing HCV infection and associated immune responses.

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Hepatitis B Virus Infection: A Mini Review

Hepatitis B and C viruses (HBV and HCV) are the leading causes of end-stage liver disease worldwide. Although there is a potent vaccine against HBV, many new infections are recorded annually, especially in poorly resourced places which have lax vaccination policies. Again, as HBV has no cure and chronic infection is lifelong, vaccines cannot help those already infected. Studies to thoroughly understand the HBV biology and pathogenesis are limited, leaving much yet to be understood about the genomic features and their role in establishing and maintaining infection. The current knowledge of the impact on disease progression and response to treatment, especially in hyperendemic regions, is inadequate. This calls for in-depth studies on viral biology, mainly for the purposes of coming up with better management strategies for infected people and more effective preventative measures for others. This information could also point us in the direction of a cure. Here, we discuss the progress made in understanding the genomic basis of viral activities leading to the complex interplay of the virus and the host, which determines the outcome of HBV infection as well as the impact of coinfections.

Therapeutic Intervention of Serine Protease Inhibitors against Hepatitis C Virus

Hepatitis C virus (HCV) is a globally prevalent and hazardous disorder that is responsible for inducing several persistent and potentially fatal liver diseases. Current treatment strategies offer limited efficacy, often accompanied by severe and debilitating adverse effects. Consequently, there is an urgent and compelling need to develop novel therapeutic interventions that can provide maximum efficacy in combating HCV while minimizing the burden of adverse effects on patients. One promising target against HCV is the NS3-4A serine protease, a complex composed of two HCV-encoded proteins. This non-covalent heterodimer is crucial in the viral life cycle and has become a primary focus for therapeutic interventions. Although peginterferon, combined with ribavirin, is commonly employed for HCV treatment, its efficacy is hampered by significant adverse effects that can profoundly impact patients' quality of life. In recent years, the development of direct-acting antiviral agents (DAAs) has emerged as a breakthrough in HCV therapy. These agents exhibit remarkable potency against the virus and have demonstrated fewer adverse effects when combined with other DAAs. However, it is important to note that there is a potential for developing resistance to DAAs due to alterations in the amino acid position of the NS3-4A protease. This emphasizes the need for ongoing research to identify strategies that can minimize the emergence of resistance and ensure long-term effectiveness. While the combination of DAAs holds promise for HCV treatment, it is crucial to consider the possibility of drug-drug interactions. These interactions may occur when different DAAs are used concurrently, potentially compromising their therapeutic efficacy. Therefore, carefully evaluating and monitoring potential drug interactions are vital to optimize treatment outcomes. In the pursuit of novel therapeutic interventions for HCV, the field of computational biology and bioinformatics has emerged as a valuable tool. These advanced technologies and methodologies enable the development and design of new drugs and therapeutic agents that exhibit maximum efficacy, reduced risk of resistance, and minimal adverse effects. By leveraging computational approaches, researchers can efficiently screen and optimize potential candidates, accelerating the discovery and development of highly effective treatments for HCV, treatments.

Hydrogen Peroxide Inhibits Hepatitis C Virus Replication by Downregulating Hepatitis C Virus Core Levels through E6-Associated Protein-Mediated Proteasomal Degradation

Hepatitis C virus (HCV) is constantly exposed to considerable oxidative stress, characterized by elevated levels of reactive oxygen species, including hydrogen peroxide (H2O2), during acute and chronic infection in the hepatocytes of patients. However, the effect of oxidative stress on HCV replication is largely unknown. In the present study, we demonstrated that H2O2 downregulated HCV Core levels to inhibit HCV replication. For this purpose, H2O2 upregulated p53 levels, resulting in the downregulation of both the protein and enzyme activity levels of DNA methyltransferase 1 (DNMT1), DNMT3a, and DNMT3b, and activated the expression of E6-associated protein (E6AP) through promoter hypomethylation in the presence of HCV Core. E6AP, an E3 ligase, induced the ubiquitin-dependent proteasomal degradation of HCV Core in a p53-dependent manner. The inhibitory effect of H2O2 on HCV replication was almost completely nullified either by treatment with a representative antioxidant, N-acetyl-L-cysteine, or by knockdown of p53 or E6AP using a specific short hairpin RNA, confirming the roles of p53 and E6AP in the inhibition of HCV replication by H2O2. This study provides insights into the mechanisms that regulate HCV replication under conditions of oxidative stress in patients.

NK cell subsets and dysfunction during viral infection: a new avenue for therapeutics?

In the setting of viral challenge, natural killer (NK) cells play an important role as an early immune responder against infection. During this response, significant changes in the NK cell population occur, particularly in terms of their frequency, location, and subtype prevalence. In this review, changes in the NK cell repertoire associated with several pathogenic viral infections are summarized, with a particular focus placed on changes that contribute to NK cell dysregulation in these settings. This dysregulation, in turn, can contribute to host pathology either by causing NK cells to be hyperresponsive or hyporesponsive. Hyperresponsive NK cells mediate significant host cell death and contribute to generating a hyperinflammatory environment. Hyporesponsive NK cell populations shift toward exhaustion and often fail to limit viral pathogenesis, possibly enabling viral persistence. Several emerging therapeutic approaches aimed at addressing NK cell dysregulation have arisen in the last three decades in the setting of cancer and may prove to hold promise in treating viral diseases. However, the application of such therapeutics to treat viral infections remains critically underexplored. This review briefly explores several therapeutic approaches, including the administration of TGF-β inhibitors, immune checkpoint inhibitors, adoptive NK cell therapies, CAR NK cells, and NK cell engagers among other therapeutics.

Oncogenic Viruses and the Epigenome: How Viruses Hijack Epigenetic Mechanisms to Drive Cancer

Globally, viral infections substantially contribute to cancer development. Oncogenic viruses are taxonomically heterogeneous and drive cancers using diverse strategies, including epigenomic dysregulation. Here, we discuss how oncogenic viruses disrupt epigenetic homeostasis to drive cancer and focus on how virally mediated dysregulation of host and viral epigenomes impacts the hallmarks of cancer. To illustrate the relationship between epigenetics and viral life cycles, we describe how epigenetic changes facilitate the human papillomavirus (HPV) life cycle and how changes to this process can spur malignancy. We also highlight the clinical impact of virally mediated epigenetic changes on cancer diagnosis, prognosis, and treatment.

Exploring boron applications in modern agriculture: Antifungal activities and mechanisms of phenylboronic acid derivatives

BACKGROUND

The unreasonable use of chemical fungicides causes common adverse consequences that not only affect the environment, but also cause resistance and resurgence problems of plant pathogens, which are extremely harmful to human health, the economy, and the environment. Based on the rich biological activities of boron-based compounds, 82 phenylboronic acid derivatives were selected and their antifungal activities against six agricultural plant pathogens were determined. Combined with transcriptomics tools, the mechanism of action of compound A49 (2-chloro-5-trifluoromethoxybenzeneboronic acid) against Botrytis cinerea Pers (B. cinerea) was studied.

RESULTS

The EC₅₀ values of compounds A24, A25, A30, A31, A36, A41, A49 and B23 against all six fungi were under 10 μg/mL. Compound A49 displayed significant activity against B. cinerea (EC₅₀  = 0.39 μg/mL), which was better than that of commercial fungicide boscalid (EC₅₀  = 0.55 μg/mL). A49 not only inhibited the germination of B. cinerea spores, but also caused abnormal cell morphology, loss of cell membrane integrity, enhanced cell membrane permeability, and accumulation of intracellular reactive oxygen species. Further findings showed that A49 reduced cellular antioxidant activity, and peroxidase and catalase activities. Transcriptomic results indicated that A49 could degrade intracellular redox processes and alter the metabolism of some amino acids. Meanwhile, A49 showed obvious activity in vivo and low cytotoxicity to mammal cells.

CONCLUSION

The boron-containing small molecule compounds had high efficiency and broad-spectrum antifungal activities against six plant pathogens, and are expected to be candidate compounds for a new class of antifungal drugs. © 2023 Society of Chemical Industry.

The Role of Cytosolic Lipid Droplets in Hepatitis C Virus Replication, Assembly, and Release

The hepatitis C virus (HCV) causes chronic hepatitis by establishing a persistent infection. Patients with chronic hepatitis frequently develop hepatic cirrhosis, which can lead to liver cancer-the progressive liver damage results from the host's immune response to the unresolved infection. The HCV replication process, including the entry, replication, assembly, and release stages, while the virus circulates in the bloodstream, it is intricately linked to the host's lipid metabolism, including the dynamic of the cytosolic lipid droplets (cLDs). This review article depicts how this interaction regulates viral cell tropism and aids immune evasion by coining viral particle characteristics. cLDs are intracellular organelles that store most of the cytoplasmic components of neutral lipids and are assumed to play an increasingly important role in the pathophysiology of lipid metabolism and host-virus interactions. cLDs are involved in the replication of several clinically significant viruses, where viruses alter the lipidomic profiles of host cells to improve viral life cycles. cLDs are involved in almost every phase of the HCV life cycle. Indeed, pharmacological modulators of cholesterol synthesis and intracellular trafficking, lipoprotein maturation, and lipid signaling molecules inhibit the assembly of HCV virions. Likewise, small-molecule inhibitors of cLD-regulating proteins inhibit HCV replication. Thus, addressing the molecular architecture of HCV replication will aid in elucidating its pathogenesis and devising preventive interventions that impede persistent infection and prevent disease progression. This is possible via repurposing the available therapeutic agents that alter cLDs metabolism. This review highlights the role of cLD in HCV replication.

Natural flavonoids effectively block the CD81 receptor of hepatocytes and inhibit HCV infection: a computational drug development approach

Hepatitis C virus (HCV) infection is a major public health concern, and almost two million people are infected per year globally. This is occurred by the diverse spectrum of viral genotypes, which are directly associated with chronic liver disease (fibrosis, and cirrhosis). Indeed, the viral genome encodes three principal proteins as sequentially core, E1, and E2. Both E1 and E2 proteins play a crucial role in the attachment of the host system, but E2 plays a more fundamental role in attachment. The researchers have found the "E2-CD81 complex" at the entry site, and therefore, CD81 is the key receptor for HCV entrance in both humans, and chimpanzees. So, the researchers are trying to block the host CD81 receptor and halt the virus entry within the cellular system via plant-derived compounds. Perhaps that is why the current research protocol is designed to perform an in silico analysis of the flavonoid compounds for targeting the tetraspanin CD81 receptor of hepatocytes. To find out the best flavonoid compounds from our library, web-based tools (Swiss ADME, pKCSM), as well as computerized tools like the PyRx, PyMOL, BIOVIA Discovery Studio Visualizer, Ligplot+ V2.2, and YASARA were employed. For molecular docking studies, the flavonoid compounds docked with the targeted CD81 protein, and herein, the best-outperformed compounds are Taxifolin, Myricetin, Puerarin, Quercetin, and (-)-Epicatechin, and outstanding binding affinities are sequentially - 7.5, - 7.9, - 8.2, - 8.4, and - 8.5 kcal/mol, respectively. These compounds have possessed more interactions with the targeted protein. To validate the post docking data, we analyzed both 100 ns molecular dynamic simulation, and MM-PBSA via the YASARA simulator, and finally finds the more significant outcomes. It is concluded that in the future, these compounds may become one of the most important alternative antiviral agents in the fight against HCV infection. It is suggested that further in vivo, and in vitro research studies should be done to support the conclusions of this in silico research workflow.

The roles of epidermal growth factor receptor in viral infections

Viruses are intracellular pathogen that exploit host cellular machinery for their propagation. Extensive research on virus-host interaction have shed light on an alternative antiviral strategy that targets host cell factors. Epidermal growth factor receptor (EGFR) is a versatile signal transducer that is involved in a range of cellular processes. Numerous studies have revealed how viruses exploit the function of EGFR in different stages of viral life cycle. In general, viruses attach onto the host cell surface and interacts with EGFR to facilitate viral entry, viral replication and spread as well as evasion from host immunosurveillance. Moreover, virus-induced activation of EGFR signalling is associated with mucin expression, tissue damage and carcinogenesis that contribute to serious complications. Herein, we review our current understanding of roles of EGFR in viral infection and its potential as therapeutic target in managing viral infection. We also discuss the available EGFR-targeted therapies and their limitations.

Evolutionary characteristics and immune mutation of hepatitis C virus genotype 1b among intravenous drug users in mainland, China

China is one of the countries with the heaviest burden of hepatitis C virus (HCV) worldwide, especially subtype 1b. To better control hepatitis C, insights into the characteristics of dynamic spread and genomic mutations are urgently needed. We retrieved sequences of HCV-1b NS5B among intravenous drug users (IDUs) and general people (Non-IDUs) in China from 2000 to 2011 in NCBI. Bayesian phylogenetic and phylogeographic analyses were used to evaluate the transmission dynamics of HCV-1b. Non-synonymous substitutions were detected to illustrate immune adaptation. Evolutionary history demonstrated that HCV-1b effective population size experienced a sharp increase in 1990. HCV-1b sequences among IDUs had a higher estimated evolutionary rate (5.7185 × 10^-3  substitutions/site/year) than overall (7.7332 × 10^-4 ). 105/136 (77.2%) of HCV-1b sequences clustered into 38 networks. The average non-synonymous HCV-1b immune epitopes among IDUs were 0.211, higher than non-IDUs, especially in the HLA-A*02 molecular recognition region. All of these posed significant challenges for the prevention and treatment of HCV. Heterogeneity and genetic linkages of HCV-1b suggest that evolutionary surveillance of HCV in cities in east-central China and among IDUs could not be neglected.

Modelling T-cell immunity against hepatitis C virus with liver organoids in a microfluidic coculture system

Hepatitis C virus (HCV) remains a global public health challenge with an estimated 71 million people chronically infected, with surges in new cases and no effective vaccine. New methods are needed to study the human immune response to HCV since in vivo animal models are limited and in vitro cancer cell models often show dysregulated immune and proliferative responses. Here, we developed a CD8+ T cell and adult stem cell liver organoid system using a microfluidic chip to coculture 3D human liver organoids embedded in extracellular matrix with HLA-matched primary human T cells in suspension. We then employed automated phase contrast and immunofluorescence imaging to monitor T cell invasion and morphological changes in the liver organoids. This microfluidic coculture system supports targeted killing of liver organoids when pulsed with a peptide specific for HCV non-structural protein 3 (NS3) (KLVALGINAV) in the presence of patient-derived CD8+ T cells specific for KLVALGINAV. This demonstrates the novel potential of the coculture system to molecularly study adaptive immune responses to HCV in an in vitro setting using primary human cells.

Hepatitis C Virus NS3/4A Inhibition and Host Immunomodulation by Tannins from Terminalia chebula: A Structural Perspective

Terminalia chebula Retz. forms a key component of traditional folk medicine and is also reported to possess antihepatitis C virus (HCV) and immunomodulatory activities. However, information on the intermolecular interactions of phytochemicals from this plant with HCV and human proteins are yet to be established. Thus, by this current study, we investigated the HCV NS3/4A inhibitory and host immune-modulatory activity of phytocompounds from T. chebula through in silico strategies involving network pharmacology and structural bioinformatics techniques. To start with, the phytochemical dataset of T. chebula was curated from biological databases and the published literature. Further, the target ability of the phytocompounds was predicted using BindingDB for both HCV NS3/4A and other probable host targets involved in the immune system. Further, the identified targets were docked to the phytochemical dataset using AutoDock Vina executed through the POAP pipeline. The resultant docked complexes with significant binding energy were subjected to 50 ns molecular dynamics (MD) simulation in order to infer the stability of complex formation. During network pharmacology analysis, the gene set pathway enrichment of host targets was performed using the STRING and Reactome pathway databases. Further, the biological network among compounds, proteins, and pathways was constructed using Cytoscape 3.6.1. Furthermore, the druglikeness, side effects, and toxicity of the phytocompounds were also predicted using the MolSoft, ADVERpred, and PreADMET methods, respectively. Out of 41 selected compounds, 10 were predicted to target HCV NS3/4A and also to possess druglike and nontoxic properties. Among these 10 molecules, Chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose exhibited potent HCV NS3/4A inhibitory activity, as these scored a lowest binding energy (BE) of −8.6 kcal/mol and −7.7 kcal/mol with 11 and 20 intermolecular interactions with active site residues, respectively. These findings are highly comparable with Asunaprevir (known inhibitor of HCV NS3/4A), which scored a BE of −7.4 kcal/mol with 20 key intermolecular interactions. MD studies also strongly suggest that chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose as promising leads, as these molecules showed stable binding during 50 ns of production run. Further, the gene set enrichment and network analysis of 18 protein targets prioritized 10 compounds and were predicted to potentially modulate the host immune system, hemostasis, cytokine levels, interleukins signaling pathways, and platelet aggregation. On overall analysis, this present study predicts that tannins from T. chebula have a potential HCV NS3/4A inhibitory and host immune-modulatory activity. However, further experimental studies are required to confirm the efficacies.

Feature-extraction and analysis based on spatial distribution of amino acids for SARS-CoV-2 Protein sequences

BACKGROUND AND OBJECTIVE

The world is currently facing a global emergency due to COVID-19, which requires immediate strategies to strengthen healthcare facilities and prevent further deaths. To achieve effective remedies and solutions, research on different aspects, including the genomic and proteomic level characterizations of SARS-CoV-2, are critical. In this work, the spatial representation/composition and distribution frequency of 20 amino acids across the primary protein sequences of SARS-CoV-2 were examined according to different parameters.

METHOD

To identify the spatial distribution of amino acids over the primary protein sequences of SARS-CoV-2, the Hurst exponent and Shannon entropy were applied as parameters to fetch the autocorrelation and amount of information over the spatial representations. The frequency distribution of each amino acid over the protein sequences was also evaluated. In the case of a one-dimensional sequence, the Hurst exponent (HE) was utilized due to its linear relationship with the fractal dimension (D), i.e. D+HE=2, to characterize fractality. Moreover, binary Shannon entropy was considered to measure the uncertainty in a binary sequence then further applied to calculate amino acid conservation in the primary protein sequences.

RESULTS AND CONCLUSION

Fourteen (14) SARS-CoV protein sequences were evaluated and compared with 105 SARS-CoV-2 proteins. The simulation results demonstrate the differences in the collected information about the amino acid spatial distribution in the SARS-CoV-2 and SARS-CoV proteins, enabling researchers to distinguish between the two types of CoV. The spatial arrangement of amino acids also reveals similarities and dissimilarities among the important structural proteins, E, M, N and S, which is pivotal to establish an evolutionary tree with other CoV strains.

Discovery of Novel HCV NS5B polymerase inhibitor, 2-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)-N-(2-fluorobenzyl)acetamide via molecular docking and experimental approach

Hepatitis C Virus (HCV) is a viral infection posing a severe global threat that left untreated progresses to end-stage liver disease, including cirrhosis and hepatocellular carcinoma (HCC). Moreover, no prophylactic approach exists so far enabling its prevention. The NS5B polymerase holds special significance as the target of intervention against HCV infection. The current study kindles benzothiazine derivatives against HCV NS5B polymerase through in silico and experimental approaches. Following docking, the compound 2-(3,4-dimethyl-5,5-dioxidobenzo[e]pyrazolo[4,3-c][1,2]thiazin-2(4H)-yl)-N-(2-fluorobenzyl)acetamide was revealed to form effective binding interaction in the proposed site of HCV NS5B with a score of -10 kcal/mol and subsequently was deciphered through molecular dynamics (MD) simulation study which indicated interaction of residues TYR_382, VAL_381 and HIS_467 through hydrophobic interaction and two residues such as GLU_202 and LYS_209 contributed in the formation of water bridges. The subsequent in silico pharmacological analysis revealed its safe drug profile. The cytotoxicity activity of compound 6c indicated to be non-toxic in HepG2 cells at concentration ranges from 0.001-1.0 µmol/L with >80% cell viability and diminished expression of the HCV NS5B to 98% at the dose of 1.0 µmol/L and 90% at 0.5µmol/L. Thus the hit compound 6c might be a potent NS5B polymerase inhibitor required to be validated further through in vivo and preclinical studies.

SARS-CoV-2: lessons from both the history of medicine and from the biological behavior of other well-known viruses

SARS-CoV-2 is the etiological agent of the current pandemic worldwide and its associated disease COVID-19. In this review, we have analyzed SARS-CoV-2 characteristics and those ones of other well-known RNA viruses viz. HIV, HCV and Influenza viruses, collecting their historical data, clinical manifestations and pathogenetic mechanisms. The aim of the work is obtaining useful insights and lessons for a better understanding of SARS-CoV-2. These pathogens present a distinct mode of transmission, as SARS-CoV-2 and Influenza viruses are airborne, whereas HIV and HCV are bloodborne. However, these viruses exhibit some potential similar clinical manifestations and pathogenetic mechanisms and their understanding may contribute to establishing preventive measures and new therapies against SARS-CoV-2.

The next generation of HCV vaccines: a focus on novel adjuvant development

INTRODUCTION

Considerable efforts have been made to treat and prevent acute and chronic infections caused by the hepatitis C virus (HCV). Current treatments are unable to protect people from reinfection. Hence, there is a need for development of both preventive and therapeutic HCV vaccines. Many vaccine candidates are in development to fight against HCV, but their efficacy has so far proven limited partly due to low immunogenicity.

AREAS COVERED

We explore development of novel and powerful adjuvants to achieve an effective HCV vaccine. The basis for developing strong adjuvants is to understand the innate immunity pathway, which subsequently stimulates humoral and cellular immune responses. We have also investigated immunogenicity of developed adjuvants that have been used in recent studies available in online databases such as PubMed, PMC, ScienceDirect, Google Scholar, etc.

EXPERT OPINION

Adjuvants are used as a part of vaccine formulation to boost vaccine immunogenicity and antigen delivery. Several FDA-approved adjuvants are used in licensed human vaccines. Unfortunately, no adjuvant has yet been proven to boost HCV immune responses to the extent needed for an effective vaccine. One of the promising approaches for developing an effective adjuvant is the combination of various adjuvants to trigger several innate immune responses, leading to activation of adaptive immunity.[Figure: see text].

Pathogens and Carcinogenesis: A Review

Cancer is a global health problem associated with genetics and unhealthy lifestyles. Increasingly, pathogenic infections have also been identified as contributors to human cancer initiation and progression. Most pathogens (bacteria, viruses, fungi, and parasites) associated with human cancers are categorized as Group I human carcinogens by the International Agency for Research on Cancer, IARC. These pathogens cause carcinogenesis via three known mechanisms: persistent infection that cause inflammation and DNA damage, initiation of oncogene expression, and immunosuppression activity of the host. In this review, we discuss the carcinogenesis mechanism of ten pathogens, their implications, and some future considerations for better management of the disease. The pathogens and cancers described are Helicobacter pylori (gastric cancer), Epstein-Barr virus (gastric cancer and lymphoma), Hepatitis B and C viruses (liver cancer), Aspergillus spp. (liver cancer), Opisthorchis viverrine (bile duct cancer), Clonorchis sinensis (bile duct cancer), Fusobacterium nucleatum (colorectal cancer), Schistosoma haematobium (bladder cancer); Human Papillomavirus (cervical cancer), and Kaposi's Sarcoma Herpes Virus (Kaposi's sarcoma).

HCV Proteins Modulate the Host Cell miRNA Expression Contributing to Hepatitis C Pathogenesis and Hepatocellular Carcinoma Development

Simple Summary

According to the last estimate by the World Health Organization (WHO), more than 71 million individuals have chronic hepatitis C worldwide. The persistence of HCV infection leads to chronic hepatitis, which can evolve into liver cirrhosis and ultimately into hepatocellular carcinoma (HCC). Although the pathogenic mechanisms are not fully understood, it is well established that an interplay between host cell factors, including microRNAs (miRNA), and viral components exist in all the phases of the viral infection and replication. Those interactions establish a complex equilibrium between host cells and HCV and participate in multiple mechanisms characterizing hepatitis C pathogenesis. The present review aims to describe the role of HCV structural and non-structural proteins in the modulation of cellular miRNA during HCV infection and pathogenesis.

Abstract

Hepatitis C virus (HCV) genome encodes for one long polyprotein that is processed by cellular and viral proteases to generate 10 polypeptides. The viral structural proteins include the core protein, and the envelope glycoproteins E1 and E2, present at the surface of HCV particles. Non-structural (NS) proteins consist of NS1, NS2, NS3, NS4A, NS4B, NS5a, and NS5b and have a variable function in HCV RNA replication and particle assembly. Recent findings evidenced the capacity of HCV virus to modulate host cell factors to create a favorable environment for replication. Indeed, increasing evidence has indicated that the presence of HCV is significantly associated with aberrant miRNA expression in host cells, and HCV structural and non-structural proteins may be responsible for these alterations. In this review, we summarize the recent findings on the role of HCV structural and non-structural proteins in the modulation of host cell miRNAs, with a focus on the molecular mechanisms responsible for the cell re-programming involved in viral replication, immune system escape, as well as the oncogenic process. In this regard, structural and non-structural proteins have been shown to modulate the expression of several onco-miRNAs or tumor suppressor miRNAs.

Macrophage Activation Markers, Soluble CD163 and Mannose Receptor, in Liver Fibrosis

Macrophages are essential components of the human host immune system, which upon activation facilitates a broad pallet of immunomodulatory events including release of pro- or anti-inflammatory cytokines and chemokines, restoration of immune homeostasis and/or wound healing. Moreover, some macrophage phenotypes are crucially involved in fibrogenesis through stimulation of myofibroblasts, while others promote fibrolysis. During the last decades, the role of resident liver macrophages viz. Kupffer cells and recruited monocytes/macrophages in acute and chronic liver diseases has gained interest and been extensively investigated. Specifically, the scavenger receptors CD163 and mannose receptor (CD206), expressed by macrophages, are of utmost interest since activation by various stimuli induce their shedding to the circulation. Thus, quantifying concentrations of these soluble biomarkers may be of promising clinical relevance in estimating the severity of inflammation and fibrosis and to predict outcomes such as survival. Here, we review the existing literature on soluble CD163 and soluble mannose receptor in liver diseases with a particular focus on their relationship to hepatic fibrosis in metabolic associated fatty liver disease, as well as in chronic hepatitis B and C.

Advances in detection of infectious agents by aptamer-based technologies

Infectious diseases still remain one of the biggest challenges for human health. Accurate and early detection of infectious pathogens are crucial for transmission control, clinical diagnosis, and therapy. For a traditional reason, most immunological and microbiological laboratories are equipped with instruments designated for antibody-based assays in detection of infectious pathogens or clinical diagnosis. Emerging aptamer-based technologies have pushed a shift from antibody-based to aptamer-based assays due to equal specificity, even better sensitivity, lower manufacturing cost and more flexibility in amending for chemiluminescent, electrochemical or fluorescent detection in a multifaceted and high throughput fashion in comparison of aptamer-based to antibody-based assays. The nature of aptamer-based technologies is particularly suitable for point-of-care testing in remote areas at warm or hot atmosphere, and mass screening for potential infection in pandemic of emerging infectious agents, such as SARS-CoV or SARS-CoV-2 in an epicentre or other regions. This review intends to summarize currently available aptamer-based technologies in detection of bacterial, viral, and protozoan pathogens for research and clinical application. It is anticipated that potential technologies will be further optimized and validated for clinical translation in meeting increasing demands for prompt, precise, and reliable detection of specific pathogens in various atmospheric conditions.

Hepatocellular carcinoma (HCC): Epidemiology, etiology and molecular classification

Hepatocellular carcinoma (HCC), the primary malignancy of hepatocytes, is a diagnosis with bleak outcome. According to National Cancer Institute's SEER database, the average five-year survival rate of HCC patients in the US is 19.6% but can be as low as 2.5% for advanced, metastatic disease. When diagnosed at early stages, it is treatable with locoregional treatments including surgical resection, Radio-Frequency Ablation, Trans-Arterial Chemoembolization or liver transplantation. However, HCC is usually diagnosed at advanced stages when the tumor is unresectable, making these treatments ineffective. In such instances, systemic therapy with tyrosine kinase inhibitors (TKIs) becomes the only viable option, even though it benefits only 30% of patients, provides only a modest (~3months) increase in overall survival and causes drug resistance within 6months. HCC, like many other cancers, is highly heterogeneous making a one-size fits all option problematic. The selection of liver transplantation, locoregional treatment, TKIs or immune checkpoint inhibitors as a treatment strategy depends on the disease stage and underlying condition(s). Additionally, patients with similar disease phenotype can have different molecular etiology making treatment responses different. Stratification of patients at the molecular level would facilitate development of the most effective treatment option. With the increase in efficiency and affordability of "omics"-level analysis, considerable effort has been expended in classifying HCC at the molecular, metabolic and immunologic levels. This review examines the results of these efforts and the ways they can be leveraged to develop targeted treatment options for HCC.

Reconstitution of T follicular helper-humoral immune axis with elimination of hepatitis C virus

Exhaustion of Hepatitis C Virus (HCV)-specific T cells and abnormal B cell function is a hallmark of chronic HCV infection. Direct-acting antiviral (DAA) therapies are effective in achieving sustained virologic response (SVR), however, whether successful DAA treatment reconstitute T follicular helper (T_FH)-B cell axis in HCV patients is unclear. Here, we aimed to evaluate the immunological changes in global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and B cells in 20 HCV patients who achieved SVR with Sofosbuvir and Ledipasvir for 12 weeks and compared with 15 healthy controls (HC). Global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and CD19 + B cells had significant phenotypic and functional reconstitution post DAA therapy. Reconstitution of effector, central and terminally differentiated memory cell population and increased ICOS and BCL6 expression was seen in HCV patients at SVR12. HCV-specific cytokines were also improved post DAA. Exhausted and regulatory B cells were declined whereas memory B cells were expanded post DAA therapy. Importantly, frequencies of T_FH cells were significantly associated with HCV RNA reduction, expansion of memory B and plasmablasts, while negatively associated with exhausted/regulatory B cells. Our results demonstrate that SVR with DAA therapy is effective in the reconstitution of phenotypic and functional abnormalities of T_FH-B cell axis.

Global hepatitis C elimination: history, evolution, revolutionary changes and barriers to overcome

The fundamental discovery of the hepatitis C virus (HCV) in 1989 has led to winning this year's Nobel Prize in Medicine. This achievement guided all the steps in identifying the elements of the virus, in order to develop the treatment and to increase the screening solutions, which have slowed the exposure to the virus. The management of infection started with interferon-alpha (IFN-α), which has later enhanced by adding Ribavirin. Nowadays, HCV treatment is based on direct-acting antiviral agents (DAAs). Currently, HCV infection benefits of curative treatment, with which most patients can be cured. When speaking about hepatitis C future, we can say it is looking bright, considering all the progress that has been made in recent years and all the options that we have for curing all genotypes of HCV infection. The aim of this review is to sum up the historical characteristics of HCV discovery, the evolution of treatment and screening actions, gaps, and stages for achieving the international elimination target of the World Health Organization.

Resistance to excision determines efficiency of hepatitis C virus RNA-dependent RNA polymerase inhibition by nucleotide analogs

NS5B is the RNA-dependent RNA polymerase that catalyzes the replication of the hepatitis C virus genome. It is a major target for antiviral drugs including nucleoside analogs, such as the prodrugs mericitabine and sofosbuvir, which get metabolized to 2'-fluoro-2'C-methylcytidine-5'-triphosphate and 2'-fluoro-2'C-methyluridine-5'-triphosphate, respectively. These analogs act as chain terminators after they are incorporated during RNA synthesis. Recently, it has been shown that NS5B can efficiently remove chain terminators by a nucleotide-mediated excision reaction that rescues RNA synthesis. In this study, we use transient-state kinetics to understand the efficiency of inhibition for five nucleoside analogs. We show that CTP analogs are readily incorporated into a growing primer by NS5B but are also efficiently excised. In contrast, although UMP analogs are more slowly incorporated, the excision of UMP is slow and inefficient, and modifications to the 2'-carbon of the UTP ribose ring further decreased rates of excision to an undetectable level. Taken together, these data suggest that the clinical effectiveness of sofosbuvir is largely a function of being intractable to nucleotide-mediated excision compared with similar nucleoside analogs.

Emerging resistance to directly-acting antiviral therapy in treatment of chronic Hepatitis C infection-A brief review of literature

Hepatitis caused by Hepatitis C virus (HCV) is a major cause of chronic liver disease. HCV is transmitted by injection drug use, blood transfusion, hemodialysis, organ transplantation and less frequently sexual intercourse. It has been recognized as a global health problem because of the progression to cirrhosis and hepatocellular carcinoma. Globally, about 170 million people are infected with HCV. Since the discovery of this virus in 1989, the clinical management of chronic hepatitis C infection has undergone a paradigm shift from alpha interferon to direct-acting antiviral (DAA) therapy. However, resistance to many of these antiviral agents has been reported increasingly from all over the globe. This review article focuses on the emerging HCV resistance to DAAs and the relevance of in vitro DAA resistance testing in clinical practice.

DNA sequences homologous to hepatitis C virus (HCV) in the extrachromosomal circular DNA in peripheral blood mononuclear cells of HCV-negative subjects

OBJECTIVE

This study aimed to investigate DNA sequences that are substantially homologous to the corresponding RNA sequence sections of the hepatitis C virus (HCV). These DNA sequences are present in the whole DNA extracted from peripheral blood mononuclear cells (PBMCs) of HCV-negative subjects. We presumed that these experimentally proven 5'-noncoding region (5'-NCR) homologous DNA sequences could be contained in the extrachromosomal circular DNA (eccDNA) fraction as part of the whole cellular DNA.

METHODS

Home-made polymerase chain reaction (PCR) with whole cellular and isolated eccDNA, nucleotide basic local alignment search tool (BLASTn) alignments, and tests for patterns of methylation in selected sequence sections were performed.

RESULTS

The PCR tests revealed DNA sequences of up to 320 bp that broadly matched the corresponding sequence sections of known HCV genotypes. In contrast, BLASTn alignment searches of published HCV 5'-NCR sequences with human genome databases revealed only sequence segments of up to 36 bp of the 5'-NCR. The composition of these sequences shows missing base pairs, base pair mismatches as well as complete homology with HCV reference sequences. These short sequence sections are present in numerous copies on both the same and different chromosomes. The selected sequence region within the DNA sequences of the 5'-NCR revealed a broad diversity of individual patterns of methylation.

CONCLUSIONS

The experimental results confirm our assumption that parts of the HCV 5'-NCR genomic RNA sequences are present at the DNA level in the eccDNA fraction of PBMCs. The tests for methylation patterns therein revealed individual methylomes which could represent an epigenetic feature. The respective sequence section might be subject to genetic regulation.

The phylogenetic approach for viral infectious disease evolution and epidemiology: An updating review

In the last decade, the phylogenetic approach is recurrent in molecular evolutionary analysis. On 12 May, 2019, about 2 296 213 papers are found, but typing "phylogeny" or "epidemiology AND phylogeny" only 199 804 and 20 133 are retrieved, respectively. Molecular epidemiology in infectious diseases is widely used to define the source of infection as so as the ancestral relationships of individuals sampled from a population. Coalescent theory and phylogeographic analysis have had scientific application in several, recent pandemic events, and nosocomial outbreaks. Hepatitis viruses and immunodeficiency virus (human immunodeficiency virus) have been largely studied. Phylogenetic analysis has been recently applied on Polyomaviruses so as in the more recent outbreaks due to different arboviruses type as Zika and chikungunya viruses discovering the source of infection and the geographic spread. Data on sequences isolated by the microorganism are essential to apply the phylogenetic tools and research in the field of infectious disease phylodinamics is growing up. There is the need to apply molecular phylogenetic and evolutionary methods in areas out of infectious diseases, as translational genomics and personalized medicine. Lastly, the application of these tools in vaccine strategy so as in antibiotic and antiviral researchers are encouraged.

The remarkable history of the hepatitis C virus

The infection with the hepatitis C virus (HCV) is an example of the translational research success. The reciprocal interactions between clinicians and scientists have allowed in 30 years the initiation of empirical treatments by interferon, the discovery of the virus, the development of serological and virological tools for diagnosis but also for prognosis (the non-invasive biochemical or morphological fibrosis tests, the predictors of the specific immune response including genetic IL28B polymorphisms). Finally, well-tolerated and effective treatments with oral antivirals inhibiting HCV non-structural viral proteins involved in viral replication have been marketed this last decade, allowing the cure of all infected subjects. HCV chronic infection, which is a public health issue, is a hepatic disease which may lead to a cirrhosis and an hepatocellular carcinoma (HCC) but also a systemic disease with extra-hepatic manifestations either associated with a cryoglobulinemic vasculitis or chronic inflammation. The HCV infection is the only chronic viral infection which may be cured: the so-called sustained virologic response, defined by undetectable HCV RNA 12 weeks after the end of the treatment, significantly reduces the risk of morbidity and mortality associated with hepatic and extra-hepatic manifestations which are mainly reversible. The history of HCV ends with the pangenotypic efficacy of the multiple combinations, easy to use for 8-12 weeks with one to three pills per day and little problems of tolerance. This explains the short 30 years from the virus discovery to the viral hepatitis elimination policy proposed by the World Health Organization (WHO) in 2016.

Prevalence of Hepatitis C virus genotypes in nine selected European countries: A systematic review

BACKGROUND

Hepatitis C virus (HCV) infection is a global health problem especially for its increasing level of mortality. Detailed knowledge of HCV genotypes prevalence has clinical relevance since the efficacy of therapies is impacted by genotypes and subtypes distribution. Moreover, HCV exhibits a great genetic variability regionally. To date, there are no published studies assessing HCV genotypes distribution in specific countries of the Mediterranean basin. The aim of this study was to review data published from 2000 to 2017 with the purpose to estimate genotypes distribution of HCV infection in nine European countries all located in the Mediterranean basin.

METHODS

A systematic research of peer-reviewed journals indexed in PubMed, Scopus, and EMBASE databases selected if containing data regarding distribution of HCV genotypes in nine selected European countries (Albania, Bosnia, Croatia, France, Greece, Italy, Montenegro, Slovenia, and Spain) was performed.

RESULTS

Genotype 1 is the most common (61.0%), ranging from 80.0% in Croatia to 46.0% in Greece, followed by genotype 3 (20.0%), varying from 38.0% in Slovenia to 7.0% and 8.0%, respectively, in Italy and in Albania and by genotype 4 (10.0%) that shows an increase of 1.1% with respect to data obtained till 2014 probably due to the increasing migrants arrivals to Southern Europe. G2, the fourth most frequent genotype (8.5%), particularly common in Italy (27.0%) and Albania (18.0%) might be probably introduced in Southern Italy as a result of Albanian campaign during Second World War and more and more increased by the migration flows from Albania to Italy in the 90s.

CONCLUSION

Epidemiology of HCV infection shows a high variability across the European countries that border the Mediterranean Sea. HCV genotyping is a relevant tool to monitor the dynamic process influenced by both evolving transmission trends and new migration flows on HCV scenario.

Prevalence of Hepatitis C virus genotypes in nine selected European countries: A systematic review

BACKGROUND

Hepatitis C virus (HCV) infection is a global health problem especially for its increasing level of mortality. Detailed knowledge of HCV genotypes prevalence has clinical relevance since the efficacy of therapies is impacted by genotypes and subtypes distribution. Moreover, HCV exhibits a great genetic variability regionally. To date, there are no published studies assessing HCV genotypes distribution in specific countries of the Mediterranean basin. The aim of this study was to review data published from 2000 to 2017 with the purpose to estimate genotypes distribution of HCV infection in nine European countries all located in the Mediterranean basin.

METHODS

A systematic research of peer-reviewed journals indexed in PubMed, Scopus, and EMBASE databases selected if containing data regarding distribution of HCV genotypes in nine selected European countries (Albania, Bosnia, Croatia, France, Greece, Italy, Montenegro, Slovenia, and Spain) was performed.

RESULTS

Genotype 1 is the most common (61.0%), ranging from 80.0% in Croatia to 46.0% in Greece, followed by genotype 3 (20.0%), varying from 38.0% in Slovenia to 7.0% and 8.0%, respectively, in Italy and in Albania and by genotype 4 (10.0%) that shows an increase of 1.1% with respect to data obtained till 2014 probably due to the increasing migrants arrivals to Southern Europe. G2, the fourth most frequent genotype (8.5%), particularly common in Italy (27.0%) and Albania (18.0%) might be probably introduced in Southern Italy as a result of Albanian campaign during Second World War and more and more increased by the migration flows from Albania to Italy in the 90s.

CONCLUSION

Epidemiology of HCV infection shows a high variability across the European countries that border the Mediterranean Sea. HCV genotyping is a relevant tool to monitor the dynamic process influenced by both evolving transmission trends and new migration flows on HCV scenario.

Heterologous Immunity between Adenoviruses and Hepatitis C Virus (HCV): Recombinant Adenovirus Vaccine Vectors Containing Antigens from Unrelated Pathogens Induce Cross-Reactive Immunity Against HCV Antigens

Host immune responses play an important role in the outcome of infection with hepatitis C virus (HCV). They can lead to viral clearance and a positive outcome, or progression and severity of chronic disease. Extensive research in the past >25 years into understanding the immune responses against HCV have still resulted in many unanswered questions implicating a role for unknown factors and events. In our earlier studies, we made a surprising discovery that peptides derived from structural and non-structural proteins of HCV have substantial amino acid sequence homologies with various proteins of adenoviruses and that immunizing mice with a non-replicating, non-recombinant adenovirus vector leads to induction of a robust cross-reactive cellular and humoral response against various HCV antigens. In this work, we further demonstrate antibody cross-reactivity between Ad and HCV in vivo. We also extend this observation to show that recombinant adenoviruses containing antigens from unrelated pathogens also possess the ability to induce cross-reactive immune responses against HCV antigens along with the induction of transgene antigen-specific immunity. This cross-reactive immunity can (a) accommodate the making of dual-pathogen vaccines, (b) play an important role in the natural course of HCV infection and (c) provide a plausible answer to many unexplained questions regarding immunity to HCV.

Sofosbuvir-velpatasvir: A single-tablet treatment for hepatitis C infection of all genotypes

PURPOSE

The pharmacology, pharmacokinetics, interaction potential, efficacy, and safety of the newest direct-acting antiviral (DAA) medication for the treatment of chronic hepatitis C are reviewed.

SUMMARY

Nonstructural proteins 5A (NS5A) and 5B (NS5B) are key drivers of hepatitis C virus (HCV) replication. Velpatasvir, an inhibitor of NS5A, was coformulated with the NS5B inhibitor sofosbuvir to provide a single-tablet combination DAA (Epclusa, Gilead Sciences). Sofosbuvir-velpatasvir was shown to have excellent activity against the 6 most prevalent HCV genotypes in the United States, with reported rates of sustained virological response at 12 weeks after treatment completion ranging from 95% to 100% in various HCV-infected populations, including patients with compensated cirrhosis and prior treatment failures. In patients with decompensated cirrhosis or HIV coinfection, reported cure rates are 85-100% and 92-100%, respectively. The duration of treatment with sofosbuvir-velpatasvir is 12 weeks regardless of the HCV genotype involved, previous treatment, and the presence of cirrhosis or baseline resistance-associated NS5A mutations. In patients with decompensated cirrhosis, sofosbuvir-velpatasvir must be used in combination with ribavirin. Sofosbuvir-velpatasvir was well tolerated in clinical trials; adverse effects reported at a rate of ≥10% were fatigue, headache, nausea, and nasopharyngitis.

CONCLUSION

Sofosbuvir-velpatasvir is a DAA and the first single-tablet regimen to treat HCV infection caused by all genotypes. The efficacy and tolerability of sofosbuvir-velpatasvir have been observed in patients with types of HCV infection that traditionally have been difficult to treat.

The remarkable history of the hepatitis C virus

The infection with the hepatitis C virus (HCV) is an example of the translational research success. The reciprocal interactions between clinicians and scientists have allowed in 30 years the initiation of empirical treatments by interferon, the discovery of the virus, the development of serological and virological tools for diagnosis but also for prognosis (the non-invasive biochemical or morphological fibrosis tests, the predictors of the specific immune response including genetic IL28B polymorphisms). Finally, well-tolerated and effective treatments with oral antivirals inhibiting HCV non-structural viral proteins involved in viral replication have been marketed this last decade, allowing the cure of all infected subjects. HCV chronic infection, which is a public health issue, is a hepatic disease, which may lead to a cirrhosis and an hepatocellular carcinoma (HCC) but also a systemic disease with extra-hepatic manifestations either associated with a cryoglobulinemic vasculitis or chronic inflammation. The HCV infection is the only chronic viral infection, which may be cured: the so-called sustained virologic response, defined by undetectable HCV RNA 12 weeks after the end of the treatment, significantly reduces the risk of morbidity and mortality associated with hepatic and extra-hepatic manifestations, which are mainly reversible. The history of HCV ends with the pangenotypic efficacy of the multiple combinations, easy to use for 8-12 weeks with one to three pills per day and little problems of tolerance. This explains the short 30 years from the virus discovery to the viral hepatitis elimination policy proposed by the World Health Organization (WHO) in 2016.

Phylogenetic analysis of hepatitis C virus among HIV/ HCV co-infected patients in Nigeria

Hepatitis C virus (HCV) infection has been associated with liver disease including liver cirrhosis and hepatocellular carcinoma (HCC) in chronically-infected persons. However, in HIV/HCV co-infected patients, increased rate of progression to cirrhosis and HCC has been reported. Limited information exists regarding genetic variants of HCV circulating among co-infected patients, which could be important in the design of broadly protective vaccine and management of the disease. Here, we determined the genotypes of HCV isolates circulating among HIV/HCV co-infected patients in Ibadan, southwestern Nigeria. One hundred and twenty-five HIV/HCV IgM positive samples obtained from HIV laboratory, University of Ibadan were used for this study. HCV NS5B gene was amplified using polymerase chain reaction (PCR). The amplified NS5B gene was sequenced using gene specific primers. Twenty isolates were amplified, out of which 13 were successfully sequenced. Phylogenetic analysis of the 13 sequenced isolates showed three HCV subtypes 1a, 3a and 5a belonging to genotypes 1, 3 and 5 respectively. Ten isolates (77%) belong to subtype 5a, followed by 2 isolates (15%) subtype 1a and 1 isolate (8%) was subtype 3a. The predominant HCV genotype was 5, followed by genotype 1 (subtype 1a). The findings, as well as the observed mutations in NS5B gene, indicate the need for screening and monitoring of HIV/HCV co-infected patients. Further study to determine the phylogeny of isolates circulating in other parts of Nigeria will be carried out.

Hepatitis C virus direct-acting antiviral nonadherence: Relationship to sustained virologic response and identification of at-risk patients

OBJECTIVES

There is a dearth of literature on effects of nonadherence to hepatitis C virus (HCV) direct-acting antiviral (DAA) regimens; thus, the objective of our study was to assess the impact of adherence on sustained virologic response (SVR) and evaluate factors associated with nonadherence, such as race, psychiatric comorbidities, and therapy length.

METHODS

We conducted a retrospective cohort study of patients completing DAA treatment between January 2014 and May 2016 within an interdisciplinary hepatology clinic. Adherence was defined a priori as 95% or greater of DAA doses taken within the prescribed treatment period. Post hoc analyses were done with adherence thresholds ≥ 90%, ≥ 85%, and ≥ 80% and adherence as a continuous percentage. Patients lost to follow-up before completing therapy or that discontinued therapy early were excluded from analyses. The association between adherence and SVR rates was assessed using Fisher exact test (for adherence thresholds) and the Wilcoxon rank-sum test (for continuous adherence). Factors associated with adherence were assessed similarly using Fisher exact and Wilcoxon rank-sum tests and multivariable logistic regression.

RESULTS

Overall adherence was high, with an average of 97.8% of DAA doses taken within the prescribed treatment period. Achievement of SVR was not significantly different in adherent and nonadherent patients, at an adherence threshold of 95% or greater (93.4% vs. 88.5%; P = 0.246) or any of the post hoc adherence thresholds (≥ 90% [93.3% vs. 84.0%; P = 0.098], ≥ 85% [92.8% vs. 91.7%; P = 0.601], ≥ 80% [92.9% vs. 80.0%; P = 0.315], or as a continuous percentage [P = 0.328]). Black patients were significantly more likely to be nonadherent to DAAs than non-black patients at each adherence threshold (P < 0.05). No other factors evaluated were associated with nonadherence.

CONCLUSION

A numerically higher but not statistically significant SVR failure rate was noted in nonadherent patients, although the gold standard definition for adherence remains to be established. Black patients may require additional adherence support.

Event-related evoked potential versus clinical tests in assessment of subclinical cognitive impairment in chronic hepatitis C virus

Context

Chronic infection by hepatitis C virus causes impairment in neurocognitive function in up to 50% of patients which may not be detected by clinical tests.

Aim

Early detection of neurocognitive impairment in chronic hepatitis C patients and investigating the cognitive function in HCV patient by p300 and clinical test.

Materials and methods

The study included 60 patients with chronic hepatitis C and 30 healthy controls. Participants were subjected to a biochemical, hematological assessment, mini-mental state examination, Montreal Cognitive Assessment, P300, polymerase chain reaction (PCR), and fibroscan made for hepatitis C patients.

Results

The digit span, attention, concentration, and memory were significantly lower in patients than controls. The delayed P300 peak latency and the reduction of its amplitude were significantly evident in patients with liver fibrosis than the controls and patients without fibrosis. These abnormalities were significantly higher with increasing the grade of fibrosis. All patients with cognitive impairment (reduced mini-mental state score) had abnormal P300-evoked responses. P300 could detect neurocognitive impairment in some patients with normal neurocognitive functions by clinical test. P300 had sensitivity (100%), specificity (59.26), positive predictive value (75%), negative predictive value (100%), and accuracy (81.67) in the detection of neurocognitive impairment in HCV patient.

Conclusion

Patients with chronic hepatitis C infection had significant impairment in their cognitive functions. This impairment increases with the increase in grade of hepatic fibrosis. P300 can detect minimal and subclinical impairment of cognitive function at early stages of chronic hepatitis with accuracy (81.67).

Trial registration

PACTR on 19 march 2018 retrospectively. Identification number for the registry is PACTR201804003215168.

Hepatitis C virus infection and chronic renal disease: A review

Hepatitis C virus (HCV) is a parenterally-transmitted hepatotropic virus that often causes chronic infection, which can progress to cirrhosis and hepatocellular carcinoma. Development of highly effective direct-acting anti-viral agents (DAAs) has led to a paradigm change in the treatment of HCV infection over the last 4-5 years. Patients with chronic kidney disease (CKD) are at a higher risk of acquiring HCV infection. In these patients, diagnosis of HCV infection, assessment of the consequent liver disease and management of HCV infection pose some specific problems. This article reviews the available recent information on HCV infection and CKD, including the association between these conditions and their effect on each other, and prevention, evaluation, and management of HCV infection in persons with CKD. This review looks at this issue particularly from the perspective of readers in Asia, especially India, since the epidemiology of HCV-CKD association and the repertoire of anti-HCV drugs available in this region differ from those elsewhere.

Recent trends in molecular epidemiology of Hepatitis C virus in Mardan, KPK Pakistan

To determine the genotypic distribution of HCV, frequency of risk factors involved in its transmission, and correlation of genotype with viral load in Mardan population which is the second largest city of Khyber Pakhtunkhwa (KPK), Pakistan. Blood samples of 1140 were collected from different regions of Mardan and major proportion of recruited patients were internally displaced people (IDPs), refugees, and slum dwellers. Complete patient's history was analyzed to assess the possible risks involved in HCV transmission. Viral genotype was determined by PCR (polymerase chain reaction) whereas, HCV RNA was measured by qRT-PCR. Data was analyzed using SPSS statistical software. Our results indicate 3a as the most abundant subtype in Mardan population followed by 3b, 2a, 2b, 4a, untypeable, mixed, 1a, and 1b. In contrast to previous findings, genotype 1 was the least prevalent genotype and the overall prevalence of HCV in Mardan population was significantly higher in females (n = 687, 60.2%) than males (n = 453, 39.7%). Significant difference between-genotypes and gender was observed in genotype 1 (p < .034) and genotype 3 (p < .004). The mean age was 44 (SD ± 9.51). The most frequently found mixed genotype was 3a + 1b and mixed genotype was more prevalent in males. The proportion of middle-aged people (41-49 years) was higher whereas, older and younger people were least infected with HCV. This is the first study that showed substantial correlation of genotype 3 with low and intermediate viral load in Mardan population. Moreover, high and extremely high viral load was associated with other genotypes. Our findings showed that most of the patients who experienced high and extremely high viremia in their blood were males and belonged to Takhat Bhai and Mardaan regions. There were significant difference in the prevalence of HCV genotype 3a (p = .001) and genotype 3b (p = .005) in different regions of Mardan. Pre-treatment viral load is significantly high (p 0.001) in tehsil Mardan patients infected with HCV genotype 3 as compared to other genotypes. Unsafe medical practices such as medical and dental surgeries, intravenous drug use, and blood transfusions were the main risk factors for HCV transmission in Mardan, KPK Pakistan. This study gives clear insights into the epidemiological status of HCV in Mardan population. Genotype 3 is correlated with low and intermediate viral load whereas high viral loads were revealed among patients infected with genotypes other than genotype 3. In the absence of better data and robust epidemiological information, this detailed analysis of HCV genotypes with special reference to risk factors, pretreatment viral load, gender, and age will provide the baseline data for development of optimal HCV eradication and preventive strategies.

Hepatitis C virus genotype 3: clinical features, current and emerging viral inhibitors, future challenges

Hepatitis C virus (HCV) represents a global burden on healthcare that affects over 150 million people worldwide. In the past, HCV genotype 3 was considered difficult to treat relative to other genotypes. Genotype 3 has been associated with a higher rate of complications, including fatty liver disease, fibrosis, hepatocellular carcinoma and mortality. However, with the advent of first- and second-generation direct-acting antivirals, genotype 3 can be treated effectively. Additionally, these new drugs are well tolerated by patients and have significantly fewer side effects compared to ribavirin and interferon-based regimens. However, while great strides have been made in overcoming biological barriers, our next challenge lies in overcoming economic and financial obstacles if we are to eradicate HCV genotype 3. Herein, we review the clinical features associated with HCV genotype 3, current and emerging treatment regimens, and challenges associated with treatment.

The role of enhancer of zeste homolog 2: From viral epigenetics to the carcinogenesis of hepatocellular carcinoma

Nowadays, epigenetics covers a crucial role in different fields of science. The enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2), is a big proponent of how epigenetic changes can affect the initiation and progression of several diseases. Through its catalytic activity, responsible for the tri-methylation of lysine 27 of the histone H3 (H3K27me3), EZH2 is a good target for both diagnosis and therapy of different pathologies. A large number of studies have demonstrated its crucial role in cancer initiation and progression. Nevertheless, only recently its function in virus diseases has been uncovered; therefore, EZH2 can be an important promoter of viral carcinogenesis. This review explores the role of EZH2 in viral epigenetics based on recent progress that demonstrated the role of this protein in virus environment. In particular, the review focuses on EZH2 behavior in Hepatitis B Virus, analyzing its role in the rise of Hepatocellular Carcinoma.

Hepatitis C virus: Morphogenesis, infection and therapy

Hepatitis C virus (HCV) is a major cause of liver diseases including liver cirrhosis and hepatocellular carcinoma. Approximately 3% of the world population is infected with HCV. Thus, HCV infection is considered a public healthy challenge. It is worth mentioning, that the HCV prevalence is dependent on the countries with infection rates around 20% in high endemic countries. The review summarizes recent data on HCV molecular biology, the physiopathology of infection (immune-mediated liver damage, liver fibrosis and lipid metabolism), virus diagnostic and treatment. In addition, currently available in vitro, ex vivo and animal models to study the virus life cycle, virus pathogenesis and therapy are described. Understanding of both host and viral factors may in the future lead to creation of new approaches in generation of an efficient therapeutic vaccine.

Genetic Diversity of Hepatitis C Virus Among Blood Donors and Patients with Clinical Hepatitis in Ibadan, Nigeria

Hepatitis C virus (HCV) infection is responsible for liver diseases and hepatocellular carcinoma in chronically-infected patients. Owing to high sequence variability in HCV genome, numerous subtypes have emerged. This study determined HCV strains among patients with clinical hepatitis and blood donors in Ibadan. Blood samples were collected from consented 176 subjects who tested positive to HCV IgM antibodies, including 99 patients with clinical hepatitis and 77 apparently healthy blood donors. Viral RNA was extracted from blood samples, while presence of HCV was tested by amplifying the NS5B gene using polymerase chain reaction (PCR). The amplified NS5B gene was sequenced and sequences were aligned on MEGA 7.0. Phylogenetic tree was constructed with Neighbor-Joining method. Data were analyzed using descriptive statistics at P<0 .05. The NS5B gene was amplified in 38 samples, of which 29 were successfully sequenced. Phylogenetic analysis revealed three of seven known genotypes of HCV including genotypes / subtypes 1a (34.5%), 1b (17.2%), 2b (13.8%), 2c (3.6%) and 5a (31.3%). Subtypes 1b and 2b were found among patients with clinical hepatitis, while the single 2c was found among donors. Although subtype 1a was detected among both populations, its rate was higher among blood donors (P = 0 .003). Subtype 5a was found among the two groups (P= 1. 00). HCV subtypes 1a and 5a are the predominant strains in Ibadan. The diversity of HCV observed has implications for treatment of patients and design of a broadly protective vaccine against the virus.

Proprotein convertase subtilisin/kexin type 9 inhibits hepatitis C virus replication through interacting with NS5A

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease actively involved in regulating lipid homeostasis. Although PCSK9 has been shown to inhibit hepatitis C virus (HCV) entry and replication, the underlying mechanisms have not been thoroughly characterized. Moreover, whether PCSK9 regulates HCV translation and assembly/secretion has not been determined. We therefore further studied the effects of PCSK9 on the HCV life cycle. We showed that PCSK9 did not affect HCV translation or assembly/secretion. Overexpression of PCSK9 inhibited HCV replication in HCV genomic replicon cells in a dose-dependent manner and after cell culture-derived HCV (HCVcc) infection. Knocking down PCSK9 increased HCV replication. The gain-of-function (D374Y) or loss-of-function (Δaa. 31-52) PCSK9 mutants for low-density lipoprotein receptor (LDLR) degradation had no effect on HCV replication, suggesting that HCV replication inhibition by PCSK9 was not due to LDLR degradation. The uncleaved ProPCSK9, but not cleaved PCSK9, down-regulated HCV replication, suggesting that the auto-cleavage of PCSK9 affected HCV replication. We also found that PCSK9 interacted with NS5A through NS5A aa. 95-215, and this region played an important role in NS5A dimerization, NS5A-RNA binding and was essential for HCV replication. More importantly, NS5A dimerization and NS5A-RNA binding were suppressed by PCSK9 upon interaction. These results suggested that PCSK9 inhibited HCV replication through interaction with NS5A. Our study should help optimize anti-HCV treatment regimen in patients with abnormal lipid profiles.

Transcriptional profiling of PBMCs unravels B cell mediated immunopathogenic imprints of HCV vasculitis

B cell depletion therapy using rituximab has been shown to be effective in achieving remission in patients with HCV-mixed cryoglobulinemic (MC) vasculitis. Previously, we have demonstrated abnormalities in peripheral immune cells involving neutrophils, chemotaxis, and innate immune activation among patients with HCV-MC vasculitis when compared to HCV patients without vasculitis. In this study, we evaluated the effect of B cell depletion therapy on transcriptional profiles of peripheral blood mononuclear cells before and after riruximab therapy, in order to unravel the pathogenic mechanism involved in HCV-MC vasculitis induced by abnormal B cell proliferation. DNA microarray analysis was performed using RNA from PBMCs from seven patients with HCV-MC vasculitis and seven normal volunteers. DNA was hybridized to Affymetrix U133A chips. After normalization, differentially expressed gene list with treatment was generated using partitional clustering. RT-PCR, flow cytometry, and enzyme immunoassay (EIA) was used to validate DNA microarray findings. Differentially expressed genes included B cells and non-B cell genes. Validation of genes using purified cell subsets demonstrated distinct effect of B cell depletion therapy on non-B cells, such as monocytes, T cells, and NK cells. Notably, B lymphocyte stimulator (BLyS) levels were persistently elevated in patients who subsequently relapsed. In conclusion, pathogenesis of HCV-MC vasculitis is mediated by abnormal proliferation of B cells, driven by BLyS, leading to significant effects on non-B cells in mediating symptomatology. Future therapeutics using a combination approach of B cell depletion and proliferation may be desired to achieve long-term remission.