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Hawsawi NM, Saber T, Salama HM, Fouad WS, Hagag HM, Alhuthali HM, Eed EM, Saber T, Ismail KA, Al Qurashi HH, Altowairqi S, Samaha M, El-Hossary D. Genotypes of Hepatitis C Virus and Efficacy of Direct-Acting Antiviral Drugs among Chronic Hepatitis C Patients in a Tertiary Care Hospital. Trop Med Infect Dis 2023; 8:92. [PMID: 36828508 PMCID: PMC9967136 DOI: 10.3390/tropicalmed8020092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/20/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Hepatitis C virus (HCV) chronic infection is a major causative factor for several chronic liver diseases, including liver cirrhosis, liver cell failure, and hepatocellular carcinoma. The HCV has seven major genotypes. Genotype 4 is the most prevalent genotype in the Middle East, including Saudi Arabia, followed by genotype 1. The HCV genotype affects the response to different HCV treatments and the progression of liver disease. Currently, combinations of direct-acting antiviral drugs (DAAs) approved for the treatment of HCV achieve high cure rates with minimal adverse effects. Because real-world data from Saudi Arabia about the efficacy of DAAs are still limited, this study was conducted to assess the effectiveness of DAAs in treating patients with chronic hepatitis C and to identify the variables related to a sustained virologic response (SVR) in a real-world setting in Saudi Arabia. This prospective cohort study included 200 Saudi patients with chronic HCV who were 18 years of age or older and had been treated with DAAs at King Abdul-Aziz Specialized Hospital in Taif, Saudi Arabia, between September 2018 and March 2021. The response to treatment was assessed by whether or not an SVR had been achieved at week 12 post treatment (SVR12). An SVR12 was reached in 97.5% of patients. SVR12 rates were comparable for patients of different ages, between men and women, and between patients with and without cirrhosis. In addition, the SVR12 rates did not differ according to the infecting HCV genotype. In this study, the presence of cirrhosis and the patient's gender were independent predictors of who would not reach an SVR12 (known here as the non-SVR12 group) according to the results of univariate and multivariate binary logistic regression analyses based on the determinants of SVR12. In this population of patients with chronic HCV infection, all DAA regimens achieved very high SVR12 rates. The patients' gender and the presence of cirrhosis were independent factors of a poor response.
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Affiliation(s)
- Nahed Mohammed Hawsawi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Tamer Saber
- Departments of Internal Medicine, Faculty of Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Hussein M. Salama
- Departments of Internal Medicine, Faculty of Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Walaa S. Fouad
- Departments of Family Medicine, Faculty of Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Howaida M. Hagag
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
- Department of Pathology, Faculty of Medicine, Al-Azhar University, Cairo 11884, Egypt
| | - Hayaa M. Alhuthali
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
| | - Emad M. Eed
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
- Medical Microbiology and Immunology Department, Faculty of Medicine, Menoufia University, Shebinel Kom 32511, Egypt
| | - Taisir Saber
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Zagazig University, Zagazig 44519, Egypt
| | - Khadiga A. Ismail
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia
- Department of Parasitology, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt
| | - Hesham H. Al Qurashi
- Gastroenterology and Hepatology Department, King Abdul-Aziz Specialized Hospital, Taif 26521, Saudi Arabia
| | - Samir Altowairqi
- Gastroenterology and Hepatology Department, King Abdul-Aziz Specialized Hospital, Taif 26521, Saudi Arabia
| | - Mohmmad Samaha
- Gastroenterology and Hepatology Department, King Abdul-Aziz Specialized Hospital, Taif 26521, Saudi Arabia
| | - Dalia El-Hossary
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Zagazig University, Zagazig 44519, Egypt
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2
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Naqvi AAT, Anjum F, Shafie A, Badar S, Elasbali AM, Yadav DK, Hassan MI. Investigating host-virus interaction mechanism and phylogenetic analysis of viral proteins involved in the pathogenesis. PLoS One 2021; 16:e0261497. [PMID: 34914801 PMCID: PMC8675761 DOI: 10.1371/journal.pone.0261497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/02/2021] [Indexed: 02/07/2023] Open
Abstract
Since the emergence of yellow fever in the Americas and the devastating 1918 influenza pandemic, biologists and clinicians have been drawn to human infecting viruses to understand their mechanisms of infection better and develop effective therapeutics against them. However, the complex molecular and cellular processes that these viruses use to infect and multiply in human cells have been a source of great concern for the scientific community since the discovery of the first human infecting virus. Viral disease outbreaks, such as the recent COVID-19 pandemic caused by a novel coronavirus, have claimed millions of lives and caused significant economic damage worldwide. In this study, we investigated the mechanisms of host-virus interaction and the molecular machinery involved in the pathogenesis of some common human viruses. We also performed a phylogenetic analysis of viral proteins involved in host-virus interaction to understand the changes in the sequence organization of these proteins during evolution for various strains of viruses to gain insights into the viral origin's evolutionary perspectives.
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Affiliation(s)
| | - Farah Anjum
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Alaa Shafie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Sufian Badar
- Department of Computer Science, Jamia Millia Islamia, New Delhi, India
| | - Abdelbaset Mohamed Elasbali
- Clinical Laboratory Science, College of Applied Medical Sciences-Qurayyat, Jouf University, Sakakah, Saudi Arabia
| | - Dharmendra Kumar Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro, Yeonsu-gu, Incheon City, South Korea
| | - Md. Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, India
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3
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Tarannum H, Chauhan B, Samadder A, Roy H, Nandi S. To Explore the Potential Targets and Current Structure-based Design Strategies Utilizing Co-crystallized Ligand to Combat HCV. Curr Drug Targets 2021; 22:590-604. [PMID: 32720601 DOI: 10.2174/1389450121999200727215020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hepatitis C Virus (HCV) belongs to the Hepacivirus family. HCV has been designated as a very dreadful virus as it can attack the liver, causing inflammation and even may lead to cancer in chronic conditions. It was estimated that 71 million people around the world have chronic HCV infection. World Health Organization (WHO) reported that about 399000 people died because of chronic cirrhosis and liver cancer globally. In spite of the abundance of availability of drugs for the treatment of HCV, however, the issue of drug resistance surpasses all the possibilities of therapeutic management of HCV. Therefore, to address this issue of 'drug-resistance', various HCV targets were explored to quest the evaluation of the mechanism of the disease progression. METHODS An attempt has been made in the present study to explore the various targets of HCV involved in the mechanism(s) of the disease initiation and progression and to focus on the mode of binding of ligands, which are co-crystallized at the active cavity of different HCV targets. CONCLUSION The present study could predict some crucial features of these ligands, which possibly interacted with various amino acid residues responsible for their biological activity and molecular signaling pathway(s). Such binding mode may be considered as a template for the high throughput screening and designing of active congeneric ligands to combat HCV.
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Affiliation(s)
- Heena Tarannum
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
| | - Bhumika Chauhan
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
| | - Asmita Samadder
- Cytogenetics and Molecular Biology Lab., Department of Zoology, University of Kalyani, Kalyani, Nadia, 741235, India
| | - Harekrishna Roy
- Nirmala College of Pharmacy, Mangalagiri, Guntur, Andhra Pradesh, 522503, India
| | - Sisir Nandi
- Department of Pharmaceutical Chemistry, Global Institute of Pharmaceutical Education and Research (Affiliated to Uttarakhand Technical University), Kashipur-244713, India
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Identification of Potential HCV Inhibitors Based on the Interaction of Epigallocatechin-3-Gallate with Viral Envelope Proteins. Molecules 2021; 26:molecules26051257. [PMID: 33652639 PMCID: PMC7956288 DOI: 10.3390/molecules26051257] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/14/2021] [Accepted: 02/20/2021] [Indexed: 12/25/2022] Open
Abstract
Hepatitis C is affecting millions of people around the globe annually, which leads to death in very high numbers. After many years of research, hepatitis C virus (HCV) remains a serious threat to the human population and needs proper management. The in silico approach in the drug discovery process is an efficient method in identifying inhibitors for various diseases. In our study, the interaction between Epigallocatechin-3-gallate, a component of green tea, and envelope glycoprotein E2 of HCV is evaluated. Epigallocatechin-3-gallate is the most promising polyphenol approved through cell culture analysis that can inhibit the entry of HCV. Therefore, various in silico techniques have been employed to find out other potential inhibitors that can behave as EGCG. Thus, the homology modelling of E2 protein was performed. The potential lead molecules were predicted using ligand-based as well as structure-based virtual screening methods. The compounds obtained were then screened through PyRx. The drugs obtained were ranked based on their binding affinities. Furthermore, the docking of the topmost drugs was performed by AutoDock Vina, while its 2D interactions were plotted in LigPlot+. The lead compound mms02387687 (2-[[5-[(4-ethylphenoxy) methyl]-4-prop-2-enyl-1,2,4-triazol-3-yl] sulfanyl]-N-[3(trifluoromethyl) phenyl] acetamide) was ranked on top, and we believe it can serve as a drug against HCV in the future, owing to experimental validation.
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Rabaan AA, Al-Ahmed SH, Bazzi AM, Alfouzan WA, Alsuliman SA, Aldrazi FA, Haque S. Overview of hepatitis C infection, molecular biology, and new treatment. J Infect Public Health 2019; 13:773-783. [PMID: 31870632 DOI: 10.1016/j.jiph.2019.11.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 07/08/2019] [Accepted: 11/18/2019] [Indexed: 12/13/2022] Open
Abstract
The World Health Organization estimates that 71 million people worldwide have chronic hepatitis C viral infection. A major challenge is overall lack of public awareness of hepatitis C, particularly among infected people of their infection status. Chronic hepatitis C infection is associated with advanced liver disease, is the main cause of hepatocellular carcinoma and causes many extra-hepatic manifestations. The existence of seven viral genotypes complicates targeting of treatment. Recent years have seen the approval of many direct acting antivirals targeted at hepatitis C virus non-structural proteins. These have revolutionized therapy as they allow achievement of extremely high sustained virologic responses. Of great significance is the development of pan-genotypic drug combinations, including the NS3/4A-NS5A inhibitor combinations sofosbuvir-velpatasvir and glecaprevir-pibrentasvir. However, resistance-associated mutations can result in failure of these treatments in a small number of patients. This, combined with the high costs of treatment, highlights the importance of continued research into effective anti-hepatitis C therapies, for example aimed at viral entry. Recent developments include identification of the potential of low-cost anti-histamines for repurposing as inhibitors of hepatitis C viral entry. In this review we focus on molecular biology of hepatitis C virus, and the new developments in hepatitis C treatment.
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Affiliation(s)
- Ali A Rabaan
- Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia.
| | - Shamsah H Al-Ahmed
- Specialty Paediatric Medicine, Qatif Central Hospital, Qatif, Saudi Arabia
| | - Ali M Bazzi
- Microbiology Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Wadha A Alfouzan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait; Faculty of Medicine, Kuwait University, Dasma 35153, Kuwait
| | - Shahab A Alsuliman
- Internal Medicine and Infectious Disease Department, Dammam Medical Complex, Dammam, Saudi Arabia
| | - Fatimah A Aldrazi
- Infection Control Department, Dammam Medical Complex, Dammam, Saudi Arabia
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing & Allied Health Sciences, Jazan University, Saudi Arabia
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6
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Abd Ellah NH, Tawfeek HM, John J, Hetta HF. Nanomedicine as a future therapeutic approach for Hepatitis C virus. Nanomedicine (Lond) 2019; 14:1471-1491. [PMID: 31166139 DOI: 10.2217/nnm-2018-0348] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hepatitis C virus (HCV) is not easily cleared from the human body and in most cases turned into chronic infection. This chronicity is a major cause of liver damage, cirrhosis and hepatocellular carcinoma. Therefore, immediate detection and treatment of HCV guarantees eradication of the virus and prevention of chronicity complications. Since discovery of HCV in 1989, several emerging treatments were developed such as polyethylene glycol(PEG)-ylated interferon/ribavirin, direct acting antivirals and host targeting antivirals. Despite the progress in anti-HCV therapy, there is still a pressing need of new approaches for affordable and effective drug delivery systems using nanomedicine. In this review, the contribution of nanoparticles as a promising delivery system for HCV immunizing, diagnostic and therapeutic agents are discussed.
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Affiliation(s)
- Noura H Abd Ellah
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, Medical Sciences Building, University of Cincinnati, Cincinnati, OH 45267, USA.,Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt
| | - Hesham M Tawfeek
- Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt.,Department of Pharmaceutics & Pharmaceutical Technology, Faculty of Pharmacy, Mutah University, Karak, Jordan
| | - James John
- Central Research Facilities, Sri Ramachandra institute of higher education & research, Sri Ramachandra University, Chennai, India
| | - Helal F Hetta
- Department of Medical Microbiology & Immunology, Faculty of Medicine, Assiut University, Assiut, 71526, Egypt.,Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0595, USA
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7
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Roder AE, Vazquez C, Horner SM. The acidic domain of the hepatitis C virus NS4A protein is required for viral assembly and envelopment through interactions with the viral E1 glycoprotein. PLoS Pathog 2019; 15:e1007163. [PMID: 30730994 PMCID: PMC6382253 DOI: 10.1371/journal.ppat.1007163] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 02/20/2019] [Accepted: 01/05/2019] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) assembly and envelopment are coordinated by a complex protein interaction network that includes most of the viral structural and nonstructural proteins. While the nonstructural protein 4A (NS4A) is known to be important for viral particle production, the specific function of NS4A in this process is not well understood. We performed mutagenesis of the C-terminal acidic domain of NS4A and found that mutation of several of these amino acids prevented the formation of the viral envelope, and therefore the production of infectious virions, without affecting viral RNA replication. In an overexpression system, we found that NS4A interacted with several viral proteins known to coordinate envelopment, including the viral E1 glycoprotein. One of the NS4A C-terminal mutations, Y45F, disrupted the interaction of NS4A with E1. Specifically, NS4A interacted with the first hydrophobic region of E1, a region previously described as regulating viral particle production. Indeed, we found that an E1 mutation in this region, D72A, also disrupted the interaction of NS4A with E1. Supernatants from HCV NS4A Y45F transfected cells had significantly reduced levels of HCV RNA, however they contained equivalent levels of Core protein. Interestingly, the Core protein secreted from these cells formed high order oligomers with a density matching the infectious virus secreted from wild-type cells. These results suggest that this Y45F mutation in NS4A causes secretion of low-density Core particles lacking genomic HCV RNA. These results corroborate previous findings showing that the E1 D72A mutation also causes secretion of Core complexes lacking genomic HCV RNA, and therefore suggest that the interaction between NS4A and E1 is involved in the incorporation of viral RNA into infectious HCV particles. Our findings define a new role for NS4A in the HCV lifecycle and help elucidate the protein interactions necessary for production of infectious virus.
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Affiliation(s)
- Allison E Roder
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Christine Vazquez
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Stacy M Horner
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC, United States of America
- Department of Medicine, Duke University Medical Center, Durham, NC, United States of America
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8
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Zhang Y, Peng X, Ren H, Chu H, Li Y, Li G. Cholesterol modulating the orientation of His17 in hepatitis C virus p7 (5a) viroporin – A molecular dynamic simulation study. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2017.09.053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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9
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Abstract
Hepatitis C, caused by the hepatitis C virus (HCV) that attacks the liver and leads to inflammation, is a severe threat to human health. Pegylated interferon α (INF-α) and ribavirin based therapy was once the standard therapy for HCV infection. However, it is suboptimal in efficacy and poorly tolerated in some patients. In the last five years, four classes of direct antiviral drugs (NAAs) that target non-structural proteins (NS) of the virus including NS3/NS4A, NS5A, and NS5B have been developed and opened a new era in HCV treatment as they are more effective and tolerable than the INF-α and ribavirin combination regimen. Importantly, the newly introduced multiple NAAs combination therapy makes it possible to eradicate all genotypes of HCV. We review recent progress on the research and development of DAAs in the present article.
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Affiliation(s)
- Jianjun Gao
- Department of Pharmacology, Qingdao University School of Pharmacy
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10
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Manzoor S, Akhtar U, Naseem S, Khalid M, Mazhar M, Parvaiz F, Khaliq S. Ionotropic Purinergic Receptors P2X4 and P2X7: Proviral or Antiviral? An Insight into P2X Receptor Signaling and Hepatitis C Virus Infection. Viral Immunol 2016; 29:401-8. [PMID: 27526181 DOI: 10.1089/vim.2016.0008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purinergic P2X receptors are plasma membrane bound, ATP-gated ion channels that are expressed on wide range of cells and respond to varying ATP concentrations in extracellular environment. Upon activation they increase membrane permeability for Ca(2+) ions and trigger a cascade of signaling complexes. During the course of hepatitis C virus (HCV) infection, ATP is released from the infected hepatocyte, which binds with Purinergic receptors (P2X) on peripheral blood mononuclear cells (PBMCs) and initiate downstream signaling pathways by disturbing the ionic balance of the cell. The present study investigates quantitative expression of P2X7 and P2X4 along with selected host genes PEPCK, transforming growth factor β (TGF-β), MAPK, Rho, and Akt in PBMCs of chronic HCV infection patients. PBMCs were isolated from collected blood samples of study subjects. Transcript analysis of P2X7, P2X4, and targeted downstream genes was done using quantitative real-time polymerase chain reaction. Relative expression analysis was performed by unpaired Student's t test on GraphPad Prism version 5. We found a notable increase of threefolds and 1.8-folds in the expression of P2X7 and P2X4 receptors in treatment naïve category while the expression of PEPCK, TGF-β, MAPK, AKT, and Rho A increased by 2.8, 1.9, 2.2, 2.2, and 1.8-folds, respectively. In sustained virological response patients, P2X7 significantly increased up to 3.5-folds while the expression of P2X4 receptor was increased up to twofold. In third category, treatment nonresponder, the expression of P2X7, P2X4 receptors, and targeted markers remained un-altered. This study deals with two major aspects of P2X4 and P2X7 receptors in PBMCs of chronic HCV individuals. One is their role in providing antiviral immunity to host against HCV; second aspect is the role of P2X receptors in inducing HCV pathogenesis via AKT, TGF-β, Rho A, PEPCK, and MAPK expression.
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Affiliation(s)
- Sobia Manzoor
- 1 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Bio-Sciences, National University of Sciences and Technology (NUST) , Islamabad, Pakistan
| | - Umair Akhtar
- 1 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Bio-Sciences, National University of Sciences and Technology (NUST) , Islamabad, Pakistan
| | - Sidrah Naseem
- 1 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Bio-Sciences, National University of Sciences and Technology (NUST) , Islamabad, Pakistan
| | - Madiha Khalid
- 1 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Bio-Sciences, National University of Sciences and Technology (NUST) , Islamabad, Pakistan
| | - Misha Mazhar
- 1 Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Bio-Sciences, National University of Sciences and Technology (NUST) , Islamabad, Pakistan
| | - Fahed Parvaiz
- 2 Department of Bio-Sciences, COMSATS Institute of Information Technology , Islamabad, Pakistan
| | - Saba Khaliq
- 3 University of Health Sciences , Lahore, Pakistan
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11
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El-Araby AM, Fouad AA, Hanbal AM, Abdelwahab SM, Qassem OM, El-Araby ME. Epigenetic Pathways of Oncogenic Viruses: Therapeutic Promises. Arch Pharm (Weinheim) 2016; 349:73-90. [PMID: 26754591 DOI: 10.1002/ardp.201500375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/30/2015] [Accepted: 12/04/2015] [Indexed: 01/19/2023]
Abstract
Cancerous transformation comprises different events that are both genetic and epigenetic. The ultimate goal for such events is to maintain cell survival and proliferation. This transformation occurs as a consequence of different features such as environmental and genetic factors, as well as some types of infection. Many viral infections are considered to be causative agents of a number of different malignancies. To convert normal cells into cancerous cells, oncogenic viruses must function at the epigenetic level to communicate with their host cells. Oncogenic viruses encode certain epigenetic factors that lead to the immortality and proliferation of infected cells. The epigenetic effectors produced by oncogenic viruses constitute appealing targets to prevent and treat malignant diseases caused by these viruses. In this review, we highlight the importance of epigenetic reprogramming for virus-induced oncogenesis, with special emphasis on viral epigenetic oncoproteins as therapeutic targets. The discovery of molecular components that target epigenetic pathways, especially viral factors, is also discussed.
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Affiliation(s)
- Amr M El-Araby
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Amr M Hanbal
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Omar M Qassem
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | - Moustafa E El-Araby
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanya, Jeddah, Saudi Arabia.,Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Helwan University, Cairo, Egypt
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12
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Cheng R, Tu T, Shackel N, McCaughan GW. Advances in and the future of treatments for hepatitis C. Expert Rev Gastroenterol Hepatol 2014; 8:633-47. [PMID: 24846594 DOI: 10.1586/17474124.2014.909725] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enormous progress has been made in the understanding of the hepatitis C virus and the development of novel therapeutic agents since the identification of the virus 25 years ago. From initial interferon monotherapy providing only 6% viral clearance rate in the 1980s, pharmacotherapeutics has now entered an exciting new era with direct-acting antiviral agents demonstrating viral clearance rates of more than 70%. We are now at the beginning of an era where combinations of direct-acting antiviral agents may pave the way for interferon-free regimens, even improving the viral clearance rate to near 100%.
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Affiliation(s)
- Robert Cheng
- Centenary Institute of Cancer Medicine and Cell Biology, Sydney, NSW, Australia
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13
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Carcamo WC, Calise SJ, von Mühlen CA, Satoh M, Chan EKL. Molecular cell biology and immunobiology of mammalian rod/ring structures. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 308:35-74. [PMID: 24411169 DOI: 10.1016/b978-0-12-800097-7.00002-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nucleotide biosynthesis is a highly regulated process necessary for cell growth and replication. Cytoplasmic structures in mammalian cells, provisionally described as rods and rings (RR), were identified by human autoantibodies and recently shown to include two key enzymes of the CTP/GTP biosynthetic pathways, cytidine triphosphate synthetase (CTPS) and inosine monophosphate dehydrogenase (IMPDH). Several studies have described CTPS filaments in mammalian cells, Drosophila, yeast, and bacteria. Other studies have identified IMPDH filaments in mammalian cells. Similarities among these studies point to a common evolutionarily conserved cytoplasmic structure composed of a subset of nucleotide biosynthetic enzymes. These structures appear to be a conserved metabolic response to decreased intracellular GTP and/or CTP pools. Antibodies to RR were found to develop in some hepatitis C patients treated with interferon-α and ribavirin. Additionally, the presence of anti-RR antibodies was correlated with poor treatment outcome.
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Affiliation(s)
- Wendy C Carcamo
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | - S John Calise
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA
| | | | - Minoru Satoh
- Division of Rheumatology and Clinical Immunology, Department of Medicine, University of Florida, Gainesville, Florida, USA; Department of Clinical Nursing, School of Health Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Edward K L Chan
- Department of Oral Biology, University of Florida, Gainesville, Florida, USA.
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14
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Zazrin H, Shaked H, Chill JH. Architecture of the hepatitis C virus E1 glycoprotein transmembrane domain studied by NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:784-92. [PMID: 24192053 DOI: 10.1016/j.bbamem.2013.10.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 10/24/2013] [Accepted: 10/28/2013] [Indexed: 10/26/2022]
Abstract
Oligomerization of hepatitis C viral envelope proteins E1 and E2 is essential to virus fusion and assembly. Although interactions within the transmembrane (TM) domains of these glycoproteins have proven contributions to the E1/E2 heterodimerization process and consequent infectivity, there is little structural information on this entry mechanism. Here, as a first step towards our long-term goal of understanding the interaction between E1 and E2 TM-domains, we have expressed, purified and characterized E1-TM using structural biomolecular NMR methods. An MBP-fusion expression system yielded sufficient quantities of pure E1-TM, which was solubilized in two membrane-mimicking environments, SDS- and LPPG-micelles, affording samples amenable to NMR studies. Triple resonance assignment experiments and relaxation measurements provided information on the secondary structure and global fold of E1-TM in these environments. In SDS micelles E1-TM adopts a helical conformation, with helical stretches at residues 354-363 and 371-379 separated by a more flexible segment of residues 364-370. In LPPG micelles a helical conformation was observed for residues 354-377 with greater flexibility in the 366-367 dyad, suggesting LPPG provides a more native environment for the peptide. Replacement of key positively charged residue K370 with an alanine did not affect the secondary structure of E1-TM but did change the relative positioning within the micelle of the two helices. These results lay the foundation for structure determination of E1-TM and a molecular understanding of how E1-TM flexibility enhances its interaction with E2-TM during heterodimerization and membrane fusion.
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Affiliation(s)
- Hadas Zazrin
- Department of Chemistry, Bar Ilan University, Ramat Gan 52900, Israel
| | - Hadassa Shaked
- Department of Chemistry, Bar Ilan University, Ramat Gan 52900, Israel
| | - Jordan H Chill
- Department of Chemistry, Bar Ilan University, Ramat Gan 52900, Israel.
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15
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Abstract
Hepatitis C virus (HCV) is a hepatotropic virus and a major cause of chronic hepatitis and liver disease worldwide. Initial interactions between HCV virions and hepatocytes are required for productive viral infection and initiation of the viral life cycle. Furthermore, HCV entry contributes to the tissue tropism and species specificity of this virus. The elucidation of these interactions is critical, not only to understand the pathogenesis of HCV infection, but also to design efficient antiviral strategies and vaccines. This review summarizes our current knowledge of the host factors required for the HCV-host interactions during HCV binding and entry, our understanding of the molecular mechanisms underlying HCV entry into target cells, and the relevance of HCV entry for the pathogenesis of liver disease, antiviral therapy, and vaccine development.
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16
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Hepatitis C variability, patterns of resistance, and impact on therapy. Adv Virol 2012; 2012:267483. [PMID: 22851970 PMCID: PMC3407602 DOI: 10.1155/2012/267483] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/10/2012] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C (HCV), a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma, is the most common indication for liver transplantation in the United States. Although annual incidence of infection has declined since the 1980s, aging of the currently infected population is expected to result in an increase in HCV burden. HCV is prone to develop resistance to antiviral drugs, and despite considerable efforts to understand the virus for effective treatments, our knowledge remains incomplete. This paper reviews HCV resistance mechanisms, the traditional treatment with and the new standard of care for hepatitis C treatment. Although these new treatments remain PEG-IFN-α- and ribavirin-based, they add one of the newly FDA approved direct antiviral agents, telaprevir or boceprevir. This new “triple therapy” has resulted in greater viral cure rates, although treatment failure remains a possibility. The future may belong to nucleoside/nucleotide analogues, non-nucleoside RNA-dependent RNA polymerase inhibitors, or cyclophilin inhibitors, and the treatment of HCV may ultimately parallel that of HIV. However, research should focus not only on effective treatments, but also on the development of a HCV vaccine, as this may prove to be the most cost-effective method of eradicating this disease.
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17
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Advancement in the development of models for hepatitis C research. J Biomed Biotechnol 2012; 2012:346761. [PMID: 22701302 PMCID: PMC3369559 DOI: 10.1155/2012/346761] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/02/2012] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) is a pandemic disease affecting an estimated 180 million individuals worldwide and infecting each year another ~3-4 million people making HCV a global public health issue. HCV is the main cause for chronic hepatitis, cirrhosis, and hepatocellular carcinoma. In the United States, HCV-related chronic liver disease is a leading cause of liver transplantation. Despite significant improvements in antiviral drugs, only ~50% of treated patients with HCV have viral clearance after treatment. Showing unique species specificity, HCV has a narrow range of potential hosts infecting only chimpanzees and humans. For decades, the chimpanzee model has been the only and instrumental primate for studying HCV infection; however, availability, economic, and ethical issues make the chimpanzee an unsuitable animal model today. Thus, significant research has been devoted to explore different models that are suitable in studying the biology of the virus and application in the clinical research for developing efficient and tolerable treatments for patients. This review focuses on experimental models that have been developed to date and their findings related to HCV.
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18
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Edwards VC, Tarr AW, Urbanowicz RA, Ball JK. The role of neutralizing antibodies in hepatitis C virus infection. J Gen Virol 2011; 93:1-19. [PMID: 22049091 DOI: 10.1099/vir.0.035956-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Hepatitis C virus (HCV) is a blood-borne virus estimated to infect around 170 million people worldwide and is, therefore, a major disease burden. In some individuals the virus is spontaneously cleared during the acute phase of infection, whilst in others a persistent infection ensues. Of those persistently infected, severe liver diseases such as cirrhosis and primary liver cancer may develop, although many individuals remain asymptomatic. A range of factors shape the course of HCV infection, not least host genetic polymorphisms and host immunity. A number of studies have shown that neutralizing antibodies (nAb) arise during HCV infection, but that these antibodies differ in their breadth and mechanism of neutralization. Recent studies, using both mAbs and polyclonal sera, have provided an insight into neutralizing determinants and the likely protective role of antibodies during infection. This understanding has helped to shape our knowledge of the overall structure of the HCV envelope glycoproteins--the natural target for nAb. Most nAb identified to date target receptor-binding sites within the envelope glycoprotein E2. However, there is some evidence that other viral epitopes may be targets for antibody neutralization, suggesting the need to broaden the search for neutralization epitopes beyond E2. This review provides a comprehensive overview of our current understanding of the role played by nAb in HCV infection and disease outcome and explores the limitations in the study systems currently used. In addition, we briefly discuss the potential therapeutic benefits of nAb and efforts to develop nAb-based therapies.
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Affiliation(s)
- Victoria C Edwards
- School of Molecular Medical Sciences and The Nottingham Digestive Diseases Centre Biomedical Research Unit, The University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Alexander W Tarr
- School of Molecular Medical Sciences and The Nottingham Digestive Diseases Centre Biomedical Research Unit, The University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Richard A Urbanowicz
- School of Molecular Medical Sciences and The Nottingham Digestive Diseases Centre Biomedical Research Unit, The University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Jonathan K Ball
- School of Molecular Medical Sciences and The Nottingham Digestive Diseases Centre Biomedical Research Unit, The University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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19
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Tellinghuisen TL, Evans MJ, von Hahn T, You S, Rice CM. Studying hepatitis C virus: making the best of a bad virus. J Virol 2007; 81:8853-67. [PMID: 17522203 PMCID: PMC1951464 DOI: 10.1128/jvi.00753-07] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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20
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Kouvatsis V, Argnani R, Tsitoura E, Arsenakis M, Georgopoulou U, Mavromara P, Manservigi R. Characterization of herpes simplex virus type 1 recombinants that express and incorporate high levels of HCV E2-gC chimeric proteins. Virus Res 2006; 123:40-9. [PMID: 16989918 DOI: 10.1016/j.virusres.2006.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 07/21/2006] [Accepted: 07/27/2006] [Indexed: 12/18/2022]
Abstract
We report the construction of two HSV-1 recombinants encoding chimeric forms of the E2 glycoprotein of HCV-1a composed of the ectodomain of E2 (aa384-611 or 384-711) fused to different parts of the transmembrane and cytoplasmic domain of the HSV-1 gC glycoprotein (gC). The parental HSV-1, known as KgBpK(-)gC(-), is deleted for gC and the main heparan sulphate (HS) binding domain of gB, and it exhibits impaired binding (ca. 80%) to HS compared to the wild type virus KOS [Laquerre, S., Argnani, R., Anderson, D.B., Zucchini, S., Manservigi, R., Glorioso, J.C., 1998. Heparan sulphate proteoglycan binding by herpes simplex virus type 1 glycoproteins B and C, which differ in their contributions to virus attachment, penetration, and cell-to-cell spread. J. Virol. 72, 6119-6130]. We show that gC:E2 proteins are efficiently expressed and transported to the cell surface. We also demonstrate that HSV-1 can incorporate both gC:E2 chimeric proteins into particles and show that incorporation of both chimeric molecules in the viral envelope partially restored binding (ca. 20%) of the HSV-1 recombinants to heparan sulphate. Finally, we showed that the gC:E2ScaI chimeric glycoprotein was able to bind a recombinant form of hCD81 and virion-expressed gC:E2ScaI permitted the binding of the HSV-1 recombinant virus to the hCD81 molecule.
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Affiliation(s)
- V Kouvatsis
- Molecular Virology Laboratory, Hellenic Pasteur Institute, Athens 11521, Greece
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Vauloup-Fellous C, Pène V, Garaud-Aunis J, Harper F, Bardin S, Suire Y, Pichard E, Schmitt A, Sogni P, Pierron G, Briand P, Rosenberg AR. Signal Peptide Peptidase-catalyzed Cleavage of Hepatitis C Virus Core Protein Is Dispensable for Virus Budding but Destabilizes the Viral Capsid. J Biol Chem 2006; 281:27679-92. [PMID: 16849324 DOI: 10.1074/jbc.m602587200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The capsid of hepatitis C virus (HCV) particles is considered to be composed of the mature form (p21) of core protein. Maturation to p21 involves cleavage of the transmembrane domain of the precursor form (p23) of core protein by signal peptide peptidase (SPP), a cellular protease embedded in the endoplasmic reticulum membrane. Here we have addressed whether SPP-catalyzed maturation to p21 is a prerequisite for HCV particle morphogenesis in the endoplasmic reticulum. HCV structural proteins were expressed by using recombinant Semliki Forest virus replicon in mammalian cells or recombinant baculovirus in insect cells, because these systems have been shown to allow the visualization of HCV budding events and the isolation of HCV-like particles, respectively. Inhibition of SPP-catalyzed cleavage of core protein by either an SPP inhibitor or HCV core mutations not only did not prevent but instead tended to facilitate the observation of viral buds and the recovery of virus-like particles. Remarkably, although maturation to p21 was only partially inhibited by mutations in insect cells, p23 was the only form of core protein found in HCV-like particles. Finally, newly developed assays demonstrated that p23 capsids are more stable than p21 capsids. These results show that SPP-catalyzed cleavage of core protein is dispensable for HCV budding but decreases the stability of the viral capsid. We propose a model in which p23 is the form of HCV core protein committed to virus assembly, and cleavage by SPP occurs during and/or after virus budding to predispose the capsid to subsequent disassembly in a new cell.
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22
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Villanueva RA, Rouillé Y, Dubuisson J. Interactions between virus proteins and host cell membranes during the viral life cycle. ACTA ACUST UNITED AC 2006; 245:171-244. [PMID: 16125548 PMCID: PMC7112339 DOI: 10.1016/s0074-7696(05)45006-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The structure and function of cells are critically dependent on membranes, which not only separate the interior of the cell from its environment but also define the internal compartments. It is therefore not surprising that the major steps of the life cycle of viruses of animals and plants also depend on cellular membranes. Indeed, interactions of viral proteins with host cell membranes are important for viruses to enter into host cells, replicate their genome, and produce progeny particles. To replicate its genome, a virus first needs to cross the plasma membrane. Some viruses can also modify intracellular membranes of host cells to create a compartment in which genome replication will take place. Finally, some viruses acquire an envelope, which is derived either from the plasma membrane or an internal membrane of the host cell. This paper reviews recent findings on the interactions of viral proteins with host cell membranes during the viral life cycle.
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Affiliation(s)
- Rodrigo A Villanueva
- CNRS-UPR2511, Institut de Biologie de Lille, Institut Pasteur de Lille, 59021 Lille Cedex, France
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23
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Helmy A. Convert hepatitis C virus into a non-enveloped virus like hepatitis A, by targeting its envelope rather than the RNA. Med Hypotheses 2005; 66:847-50. [PMID: 16229965 DOI: 10.1016/j.mehy.2005.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 07/25/2005] [Indexed: 11/22/2022]
Abstract
Based on the current understanding of the differences between the structure of hepatitis C virus (HCV) in one hand and the hepatitis A and E viruses (HAV and HEV) in the other hand, we hypothesize that converting the HCV into a non-enveloped virus may be the required key step in allowing viral clearance and preventing chronic viremia. Better understanding of the structure of HCV envelop, and of the mechanisms involved in its acquisition is essential for the development of agents that can interfere with "envelopization" of the newer copies of HCV RNA genome.
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Affiliation(s)
- Ahmed Helmy
- Department of Liver Transplantation, Hepatobiliary and Pancreatic Surgery, King Faisal Specialist Hospital and Research Center (KFSH&RC), MBC 72, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
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24
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Meyer K, Beyene A, Bowlin TL, Basu A, Ray R. Coexpression of hepatitis C virus E1 and E2 chimeric envelope glycoproteins displays separable ligand sensitivity and increases pseudotype infectious titer. J Virol 2004; 78:12838-47. [PMID: 15542636 PMCID: PMC524985 DOI: 10.1128/jvi.78.23.12838-12847.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Accepted: 07/22/2004] [Indexed: 02/05/2023] Open
Abstract
We have previously reported that a pseudotype virus generated by reconstitution of hepatitis C virus (HCV) chimeric envelope glycoprotein E1-G or E2-G on the surface of a temperature-sensitive mutant of vesicular stomatitis virus (VSVts045) interacts independently with mammalian cells to initiate infection. Here, we examined whether coexpression of both of the envelope glycoproteins on pseudotype particles would augment virus infectivity and/or alter the functional properties of the individual subunits. Stable transfectants of baby hamster kidney (BHK) epithelial cells expressing either one or both of the chimeric envelope glycoproteins of HCV on the cell surface were generated. The infectious titer of the VSV pseudotype, derived from a stable cell line incorporating both of the chimeric glycoproteins of HCV, was approximately 4- to 5-fold higher than that of a pseudotype bearing E1-G alone or approximately 25- to 30-fold higher than that of E2-G alone when assayed with a number of mammalian cell lines. Further studies suggested that that the E1-G/E2-G or E2-G pseudotype was more sensitive to the inhibitory effect of heparin than the E1-G pseudotype. Treatment of the E1-G/E2-G pseudotype with a negatively charged sulfated sialyl lipid (NMSO3) displayed a approximately 4-fold-higher sensitivity to neutralization than pseudotypes with either of the two individual glycoproteins. In contrast, VSVts045, used as a backbone for the generation of pseudotypes, displayed at least 20-fold-higher sensitivity to NMSO3-mediated inhibition of virus plaque formation. The effect of low-density lipoprotein on the E1-G pseudotype was greater than that apparent for the E1-G/E2-G pseudotype. The treatment of cells with monoclonal antibodies to CD81 displayed an inhibitory effect upon the pseudotype with E1-G/E2-G or with E2-G alone. Taken together, our results indicate that the HCV E1 and E2 glycoproteins have separable functional properties and that the presence of these two envelope glycoproteins on VSV/HCV pseudotype particles increases infectious titer.
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Affiliation(s)
- Keith Meyer
- Division of Infectious Diseases and Immunology, Saint Louis University, 3635 Vista Ave., FDT-8N, St. Louis, MO 63110, USA
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25
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Op De Beeck A, Rouillé Y, Caron M, Duvet S, Dubuisson J. The transmembrane domains of the prM and E proteins of yellow fever virus are endoplasmic reticulum localization signals. J Virol 2004; 78:12591-602. [PMID: 15507646 PMCID: PMC525104 DOI: 10.1128/jvi.78.22.12591-12602.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The immature flavivirus particle contains two envelope proteins, prM and E, that are associated as a heterodimer. Virion morphogenesis of the flaviviruses occurs in association with endoplasmic reticulum (ER) membranes, suggesting that there should be accumulation of the virion components in this compartment. This also implies that ER localization signals must be present in the flavivirus envelope proteins. In this work, we looked for potential subcellular localization signals in the yellow fever virus envelope proteins. Confocal immunofluorescence analysis of the subcellular localization of the E protein in yellow fever virus-infected cells indicated that this protein accumulates in the ER. Similar results were obtained with cells expressing only prM and E. Chimeric proteins containing the ectodomain of CD4 or CD8 fused to the transmembrane domains of prM or E were constructed, and their subcellular localization was studied by confocal immunofluorescence and by analyzing the maturation of their associated glycans. Although a small fraction was detected in the ER-to-Golgi intermediate and Golgi compartments, these chimeric proteins were located mainly in the ER. The C termini of prM and E form two antiparallel transmembrane alpha-helices. Interestingly, the first transmembrane passage contains enough information for ER localization. Taken altogether, these data indicate that, besides their role as membrane anchors, the transmembrane domains of yellow fever virus envelope proteins are ER retention signals. In addition, our data show that the mechanisms of ER retention of the flavivirus and hepacivirus envelope proteins are different.
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Affiliation(s)
- Anne Op De Beeck
- Unité Hépatite C, CNRS-UPR2511, Institut de Biologie de Lille, 1 rue Calmette, BP447, 59021 Lille cedex, France
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26
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Köhl W, Zimmer G, Greiser-Wilke I, Haas L, Moennig V, Herrler G. The surface glycoprotein E2 of bovine viral diarrhoea virus contains an intracellular localization signal. J Gen Virol 2004; 85:1101-1111. [PMID: 15105527 DOI: 10.1099/vir.0.19740-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The intracellular transport of the surface glycoprotein E2 of bovine viral diarrhoea virus was analysed by expressing the cloned gene in the absence of other viral proteins. Immunofluorescence analysis and surface biotinylation indicated that E2 is located in an early compartment of the secretory pathway and not transported to the cell surface. In agreement with this result, E2 was found to contain only high-mannose oligosaccharide side-chains but no N-glycans of the complex type. To define the intracellular localization signal of the E2 protein, chimeric proteins were generated. E2 chimeras containing the MT (membrane anchor plus carboxy-terminal domain) of the G protein of vesicular stomatitis virus (VSV) or of the F protein of bovine respiratory syncytial virus (BRSV) were transported to the cell surface. On the other hand, VSV G protein containing the MT domain of E2 was detected only in the ER, indicating that this domain contains an ER localization signal. A chimeric E2 protein, in which not the membrane anchor but only the carboxy-terminal end was replaced by the corresponding domain of the BRSV F protein, was also localized in the ER. Therefore, it was concluded that the membrane anchor contains the ER localization signal of E2. Interestingly, the ER export signal within the VSV G protein cytoplasmic tail was found to overrule the ER localization signal in the E2 protein membrane anchor.
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Affiliation(s)
- Wiebke Köhl
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Gert Zimmer
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Irene Greiser-Wilke
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Ludwig Haas
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Volker Moennig
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Georg Herrler
- Institut für Virologie, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
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Slater-Handshy T, Droll DA, Fan X, Di Bisceglie AM, Chambers TJ. HCV E2 glycoprotein: mutagenesis of N-linked glycosylation sites and its effects on E2 expression and processing. Virology 2004; 319:36-48. [PMID: 14967486 DOI: 10.1016/j.virol.2003.10.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Revised: 10/07/2003] [Accepted: 10/07/2003] [Indexed: 12/31/2022]
Abstract
An expression system for analysis of the synthesis and processing of the E2 glycoprotein of a hepatitis C virus (HCV) genotype 1a strain was developed in transiently transfected cells. E2 proteins representing the entire length of the protein, including the transmembrane segment (E2) as well as two truncated versions (E2(660) and E2(715)), were characterized for acquisition of N-linked glycans and transport to the media of transfected cells. To investigate the utilization of the 10 potential N-linked glycosylation sites on this E2 protein, a series of mutations consisting of single or multiple (two, three, four or eight) ablations of asparagine residues in the background of the E2(660) construct were analyzed. E2(660) proteins harboring single or multiple site mutations were produced at levels similar to that of wild-type protein, but secretion of the single mutants was mildly diminished, and elimination of two or more sites dramatically reduced delivery of the protein to the media. Similar results were obtained in Huh-7 cells with respect to intracellular synthesis and secretion of the mutant proteins. Analysis of oligosaccharide composition using endoglycosidase digestion revealed that all of the glycan residues on the intracellular forms of E2(660), E2(715), and E2 contained N-linked glycans modified into high-mannose carbohydrates, in contrast to the secreted forms, which were endo H resistant. The parental E2(660) protein could be readily detected in Huh-7 cells using anti-polyhistidine or antibody to recombinant E2. In contrast, E2(660) lacking the eight N-linked glycans was expressed but not detectable with anti-E2 antibody, and proteins lacking four glycans exhibited reduced reactivity. These experiments provide direct evidence that the presence of multiple N-linked glycans is required for the proper folding of the E2 protein in the ER and secretory pathway as well as for formation of its antigenic structure.
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Affiliation(s)
- Tiffany Slater-Handshy
- Department of Molecular Microbiology and Immunology, St. Louis University School of Medicine, St. Louis, MO 63104, USA.
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