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Diao P, Wang X, Jia F, Kimura T, Hu X, Shirotori S, Nakamura I, Sato Y, Nakayama J, Moriya K, Koike K, Gonzalez FJ, Aoyama T, Tanaka N. A saturated fatty acid-rich diet enhances hepatic lipogenesis and tumorigenesis in HCV core gene transgenic mice. J Nutr Biochem 2020; 85:108460. [PMID: 32992072 DOI: 10.1016/j.jnutbio.2020.108460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 05/25/2020] [Accepted: 06/16/2020] [Indexed: 02/07/2023]
Abstract
Previous studies suggested that high consumption of saturated fatty acid (SFA) is a risk factor for liver cancer. However, it remains unclear how dietary SFA affects liver tumorigenesis. This study aimed to investigate the impact of a SFA-rich diet on hepatic tumorigenesis using hepatitis C virus core gene transgenic (HCVcpTg) mice that spontaneously developed hepatic steatosis and tumors with aging. Male HCVcpTg mice were treated for 15 months with a purified control diet or SFA-rich diet prepared by replacing soybean oil in the control diet with hydrogenated coconut oil, and phenotypic changes were assessed. In this special diet, almost all dietary fatty acids were SFA. Long-term feeding of SFA-rich diet to HCVcpTg mice increased hepatic steatosis, liver dysfunction, and the prevalence of liver tumors, likely due to stimulation of de novo lipogenesis, activation of the pro-inflammatory and pro-oncogenic transcription factor nuclear factor-kappa B (NF-κB), enhanced c-Jun N-terminal kinase/activator protein 1 (JNK/AP-1) signaling and induction of the oncogenes cyclin D1 and p62/sequestosome 1. The SFA-rich diet did not affect liver fibrosis or autophagy. Collectively, long-term SFA-rich diet consumption promoted hepatic tumorigenesis mainly through activation of lipogenesis, NF-κB, and JNK/AP-1 signaling. We therefore propose that HCV-infected patients should avoid excessive intake of SFA-rich foods to prevent liver cancer.
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Affiliation(s)
- Pan Diao
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan
| | - Xiaojing Wang
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan; Department of Gastroenterology, Lishui Hospital, Zhejiang University School of Medicine, Lishui, Zhejiang, People's Republic of China
| | - Fangping Jia
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takefumi Kimura
- Department of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Xiao Hu
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan; Department of Pathophysiology, Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Saki Shirotori
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan
| | - Ibuki Nakamura
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoshiko Sato
- Department of Molecular Pathology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Jun Nakayama
- Department of Molecular Pathology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kyoji Moriya
- Department of Infection Control and Prevention, The University of Tokyo, Tokyo, Japan
| | - Kazuhiko Koike
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Toshifumi Aoyama
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan
| | - Naoki Tanaka
- Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan; Research Center for Social Systems, Shinshu University, Matsumoto, Japan.
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2
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Wang CC, Cheng PN, Kao JH. Systematic review: chronic viral hepatitis and metabolic derangement. Aliment Pharmacol Ther 2020; 51:216-230. [PMID: 31746482 DOI: 10.1111/apt.15575] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/08/2019] [Accepted: 10/17/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND The liver has a critical role in the metabolism of glucose and lipids. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection leads to a spectrum of liver disease including chronic hepatitis, cirrhosis and hepatocellular carcinoma. Metabolic syndrome (MetS) has a rising incidence owing to an epidemic of type 2 diabetes mellitus (T2DM) and obesity. Non-alcoholic fatty liver disease is a liver manifestation of MetS and has become the most common cause of chronic liver disease worldwide. AIM To summarise the interplay among hepatitis viruses, MetS and its components. METHODS We searched the literature about HBV, HCV infection, MetS, fatty liver and its components from PubMed. RESULTS With respect to the viral replication cycle, lipids are important mediators between viral entry and hepatocyte in HCV infection, but not in HBV infection. Thus, HCV infection is inversely associated with hyperlipidaemia and lipid rebound occurs following sustained viral response induced by interferon-based therapy or direct antiviral agents. In addition, HCV infection is positively associated with insulin resistance, hepatic steatosis, MetS and the risk of T2DM and atherosclerosis. In contrast, HBV infection may protect infected subjects from the development of MetS and hepatic steatosis. Accumulating evidence suggests that HBV infection is inversely associated with lipid metabolism, and exhibits no conclusive association with insulin resistance or the risk of T2DM and arteriosclerosis. CONCLUSIONS In patients with viral hepatitis and concurrent metabolic diseases, a multidisciplinary approach should be given rather than simply antiviral treatment.
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Affiliation(s)
- Chia-Chi Wang
- Department of Gastroenterology and Hepatology, Buddhist Tzu Chi Medical Foundation and School of Medicine, Taipei Tzu Chi Hospital, Tzu Chi University, Hualien, Taiwan
| | - Pin-Nan Cheng
- Department of Internal Medicine, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Jia-Horng Kao
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Internal Medicine, Department of Medical Research and Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
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Abstract
This review discusses the current state of the viral metabolism field and gaps in knowledge that will be important for future studies to investigate. We discuss metabolic rewiring caused by viruses, the influence of oncogenic viruses on host cell metabolism, and the use of viruses as guides to identify critical metabolic nodes for cancer anabolism. We also discuss the need for more mechanistic studies identifying viral proteins responsible for metabolic hijacking and for in vivo studies of viral-induced metabolic rewiring. Improved technologies for detailed metabolic measurements and genetic manipulation will lead to important discoveries over the next decade.
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Affiliation(s)
- Shivani K Thaker
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - James Ch'ng
- Department of Pediatrics, Division of Hematology/Oncology, David Geffen School of Medicine, UCLA, Los Angeles, CA, 90095, USA
| | - Heather R Christofk
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA.
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, CA, 90095, USA.
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4
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Catalase and nonalcoholic fatty liver disease. Pflugers Arch 2018; 470:1721-1737. [PMID: 30120555 DOI: 10.1007/s00424-018-2195-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 02/06/2023]
Abstract
Obesity and insulin resistance are considered the main causes of nonalcoholic fatty liver disease (NAFLD), and oxidative stress accelerates the progression of NAFLD. Free fatty acids, which are elevated in the liver by obesity or insulin resistance, lead to incomplete oxidation in the mitochondria, peroxisomes, and microsomes, leading to the production of reactive oxygen species (ROS). Among the ROS generated, H2O2 is mainly produced in peroxisomes and decomposed by catalase. However, when the H2O2 concentration increases because of decreased expression or activity of catalase, it migrates to cytosol and other organelles, causing cell injury and participating in the Fenton reaction, resulting in serious oxidative stress. To date, numerous studies have been shown to inhibit the pathogenesis of NAFLD, but treatment for this disease mainly depends on weight loss and exercise. Various molecules such as vitamin E, metformin, liraglutide, and resveratrol have been proposed as therapeutic agents, but further verification of the dose setting, clinical application, and side effects is needed. Reducing oxidative stress may be a fundamental method for improving not only the progression of NAFLD but also obesity and insulin resistance. However, the relationship between NAFLD progression and antioxidants, particularly catalase, which is most commonly expressed in the liver, remains unclear. Therefore, this review summarizes the role of catalase, focusing on its potential therapeutic effects in NAFLD progression.
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Wijarnpreecha K, Thongprayoon C, Panjawatanan P, Lekuthai N, Ungprasert P. Hepatitis C virus infection and risk of gallstones: A meta-analysis. J Evid Based Med 2017; 10:263-270. [PMID: 29193901 DOI: 10.1111/jebm.12277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 11/06/2017] [Indexed: 01/11/2023]
Abstract
BACKGROUND/OBJECTIVES Gallstones and its complications are one of the most common hepatobiliary tract diseases. Several epidemiologic studies have suggested that patients with hepatitis C virus (HCV) infection might be at an increased risk of gallstones. However, the data on this relationship remain inconclusive. This meta-analysis was conducted with the aims to summarize all available evidence. METHODS A literature search was performed using MEDLINE and EMBASE databases from inception to May 2016. Studies that reported relative risks, odd ratios, or hazard ratios comparing the risk of gallstones among HCV-infected patients versus subjects without HCV infection were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method. RESULTS Eleven studies met our eligibility criteria and were included in the analysis. The pooled OR of gallstones in HCV-infected patients versus subjects without HCV infection was 1.83 (95% CI, 1.35 to 2.48, I2 = 89%). Subgroup analysis showed that significant risk was increased for both male (pooled OR of 2.07, 95% CI, 1.14 to 3.76) and female (pooled OR of 3.00, 95% CI, 2.16 to 4.17). CONCLUSIONS Our study demonstrated a significantly increased risk of gallstones among HCV-infected patients. Further studies are required to clarify how this risk should be addressed in the clinical picture.
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Affiliation(s)
- Karn Wijarnpreecha
- Department of Internal Medicine, Bassett Medical Center, Cooperstown, NY, USA
| | - Charat Thongprayoon
- Department of Internal Medicine, Bassett Medical Center, Cooperstown, NY, USA
| | | | - Natasorn Lekuthai
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Patompong Ungprasert
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Division of Rheumatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
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6
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Haga Y, Kanda T, Sasaki R, Nakamura M, Nakamoto S, Yokosuka O. Nonalcoholic fatty liver disease and hepatic cirrhosis: Comparison with viral hepatitis-associated steatosis. World J Gastroenterol 2015; 21:12989-12995. [PMID: 26675364 PMCID: PMC4674717 DOI: 10.3748/wjg.v21.i46.12989] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/07/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) including nonalcoholic steatohepatitis (NASH) is globally increasing and has become a world-wide health problem. Chronic infection with hepatitis B virus or hepatitis C virus (HCV) is associated with hepatic steatosis. Viral hepatitis-associated hepatic steatosis is often caused by metabolic syndrome including obesity, type 2 diabetes mellitus and/or dyslipidemia. It has been reported that HCV genotype 3 exerts direct metabolic effects that lead to hepatic steatosis. In this review, the differences between NAFLD/NASH and viral hepatitis-associated steatosis are discussed.
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7
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Moreau M, Rivière B, Vegna S, Aoun M, Gard C, Ramos J, Assenat E, Hibner U. Hepatitis C viral proteins perturb metabolic liver zonation. J Hepatol 2015; 62:278-85. [PMID: 25220251 DOI: 10.1016/j.jhep.2014.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 08/22/2014] [Accepted: 09/01/2014] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS The metabolic identity of a hepatocyte is determined by its position along the porto-centrilobular axis of a liver lobule. Altered patterns of metabolic liver zonation are associated with several pathologies. In hepatitis C, although only a minority of hepatocytes harbour the virus, the liver undergoes major systemic metabolic changes. We have investigated the HCV-driven mechanisms that allow the systemic loss of metabolic zonation. METHODS Transgenic mice with hepatocyte-targeted expression of all HCV proteins (FL-N/35 model) and needle biopsies from hepatitis C patients were studied with respect to patterns of lipid deposition in the context of metabolic zonation of the liver lobule. RESULTS We report that low levels of viral proteins are sufficient to drive striking alterations of hepatic metabolic zonation. In mice, a major lipogenic enzyme, fatty acid synthase, was redistributed from its normal periportal expression into the midzone of the lobule, coinciding with a highly specific midzone accumulation of lipids. Strikingly, alteration of zonation was not limited to lipogenic enzymes and appeared to be driven by systemic signalling via the Wnt/β-catenin pathway. Importantly, we show that similarly perturbed metabolic zonation appears to precede steatosis in early stages of human disease associated with HCV infection. CONCLUSIONS Our results rationalize systemic effects on liver metabolism, triggered by a minority of infected cells, thus opening new perspectives for the investigation of HCV-related pathologies.
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Affiliation(s)
- Marie Moreau
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Montpellier, France; Université de Montpellier 2, Montpellier, France; Université de Montpellier 1, Montpellier, France
| | - Benjamin Rivière
- Département de Biopathologie Cellulaire et Tissulaire des Tumeurs, Hôpital Saint Eloi-Gui de Chauliac, Centre Hospitalier Universitaire, Montpellier, France; Université de Montpellier 1, Montpellier, France
| | - Serena Vegna
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Montpellier, France; Université de Montpellier 2, Montpellier, France; Université de Montpellier 1, Montpellier, France
| | - Manar Aoun
- Départment de Biochimie, CHU, Université Montpellier I, France
| | - Christopher Gard
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Montpellier, France; Université de Montpellier 2, Montpellier, France; Université de Montpellier 1, Montpellier, France; University of Manchester, Manchester, UK
| | - Jeanne Ramos
- Département de Biopathologie Cellulaire et Tissulaire des Tumeurs, Hôpital Saint Eloi-Gui de Chauliac, Centre Hospitalier Universitaire, Montpellier, France; Université de Montpellier 1, Montpellier, France
| | - Eric Assenat
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Montpellier, France; Université de Montpellier 2, Montpellier, France; Université de Montpellier 1, Montpellier, France; Service d'Oncologie Médicale, CHU St Eloi, Montpellier, France
| | - Urszula Hibner
- CNRS, UMR 5535, Institut de Génétique Moléculaire de Montpellier, Montpellier, France; Université de Montpellier 2, Montpellier, France; Université de Montpellier 1, Montpellier, France.
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Loizides-Mangold U, Clément S, Alfonso-Garcia A, Branche E, Conzelmann S, Parisot C, Potma EO, Riezman H, Negro F. HCV 3a core protein increases lipid droplet cholesteryl ester content via a mechanism dependent on sphingolipid biosynthesis. PLoS One 2014; 9:e115309. [PMID: 25522003 PMCID: PMC4270764 DOI: 10.1371/journal.pone.0115309] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/21/2014] [Indexed: 12/22/2022] Open
Abstract
Hepatitis C virus (HCV) infected patients often develop steatosis and the HCV core protein alone can induce this phenomenon. To gain new insights into the pathways leading to steatosis, we performed lipidomic profiling of HCV core protein expressing-Huh-7 cells and also assessed the lipid profile of purified lipid droplets isolated from HCV 3a core expressing cells. Cholesteryl esters, ceramides and glycosylceramides, but not triglycerides, increased specifically in cells expressing the steatogenic HCV 3a core protein. Accordingly, inhibitors of cholesteryl ester biosynthesis such as statins and acyl-CoA cholesterol acyl transferase inhibitors prevented the increase of cholesteryl ester production and the formation of large lipid droplets in HCV core 3a-expressing cells. Furthermore, inhibition of de novo sphingolipid biosynthesis by myriocin - but not of glycosphingolipid biosynthesis by miglustat - affected both lipid droplet size and cholesteryl ester level. The lipid profile of purified lipid droplets, isolated from HCV 3a core-expressing cells, confirmed the particular increase of cholesteryl ester. Thus, both sphingolipid and cholesteryl ester biosynthesis are affected by the steatogenic core protein of HCV genotype 3a. These results may explain the peculiar lipid profile of HCV-infected patients with steatosis.
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Affiliation(s)
- Ursula Loizides-Mangold
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Sophie Clément
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Alba Alfonso-Garcia
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States of America
| | - Emilie Branche
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Stéphanie Conzelmann
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Clotilde Parisot
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
| | - Eric O. Potma
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States of America
| | - Howard Riezman
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Francesco Negro
- Division of Clinical Pathology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
- Divisions of Gastroenterology and Hepatology, University Hospital, University of Geneva School of Medicine, Geneva, Switzerland
- * E-mail:
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9
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Stearoyl coenzyme A desaturase 1 is associated with hepatitis C virus replication complex and regulates viral replication. J Virol 2014; 88:12311-25. [PMID: 25122791 DOI: 10.1128/jvi.01678-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED The hepatitis C virus (HCV) life cycle is tightly regulated by lipid metabolism of host cells. In order to identify host factors involved in HCV propagation, we have recently screened a small interfering RNA (siRNA) library targeting host genes that control lipid metabolism and lipid droplet formation using cell culture-grown HCV (HCVcc)-infected cells. We selected and characterized the gene encoding stearoyl coenzyme A (CoA) desaturase 1 (SCD1). siRNA-mediated knockdown or pharmacological inhibition of SCD1 abrogated HCV replication in both subgenomic replicon and Jc1-infected cells, while exogenous supplementation of either oleate or palmitoleate, products of SCD1 activity, resurrected HCV replication in SCD1 knockdown cells. SCD1 was coimmunoprecipitated with HCV nonstructural proteins and colocalized with both double-stranded RNA (dsRNA) and HCV nonstructural proteins, indicating that SCD1 is associated with HCV replication complex. Moreover, SCD1 was fractionated and enriched with HCV nonstructural proteins at detergent-resistant membrane. Electron microscopy data showed that SCD1 is required for NS4B-mediated intracellular membrane rearrangement. These data further support the idea that SCD1 is associated with HCV replication complex and that its products may contribute to the proper formation and maintenance of membranous web structures in HCV replication complex. Collectively, these data suggest that manipulation of SCD1 activity may represent a novel host-targeted antiviral strategy for the treatment of HCV infection. IMPORTANCE Stearoyl coenzyme A (CoA) desaturase 1 (SCD1), a liver-specific enzyme, regulates hepatitis C virus (HCV) replication through its enzyme activity. HCV nonstructural proteins are associated with SCD1 at detergent-resistant membranes, and SCD1 is enriched on the lipid raft by HCV infection. Therein, SCD1 supports NS4B-mediated membrane rearrangement to provide a suitable microenvironment for HCV replication. We demonstrated that either genetic or chemical knockdown of SCD1 abrogated HCV replication in both replicon cells and HCV-infected cells. These findings provide novel mechanistic insights into the roles of SCD1 in HCV replication.
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10
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Kessler SM, Simon Y, Gemperlein K, Gianmoena K, Cadenas C, Zimmer V, Pokorny J, Barghash A, Helms V, van Rooijen N, Bohle RM, Lammert F, Hengstler JG, Mueller R, Haybaeck J, Kiemer AK. Fatty acid elongation in non-alcoholic steatohepatitis and hepatocellular carcinoma. Int J Mol Sci 2014; 15:5762-73. [PMID: 24714086 PMCID: PMC4013594 DOI: 10.3390/ijms15045762] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/17/2014] [Accepted: 03/21/2014] [Indexed: 12/13/2022] Open
Abstract
Non-alcoholic steatohepatitis (NASH) represents a risk factor for the development of hepatocellular carcinoma (HCC) and is characterized by quantitative and qualitative changes in hepatic lipids. Since elongation of fatty acids from C16 to C18 has recently been reported to promote both hepatic lipid accumulation and inflammation we aimed to investigate whether a frequently used mouse NASH model reflects this clinically relevant feature and whether C16 to C18 elongation can be observed in HCC development. Feeding mice a methionine and choline deficient diet to model NASH not only increased total hepatic fatty acids and cholesterol, but also distinctly elevated the C18/C16 ratio, which was not changed in a model of simple steatosis (ob/ob mice). Depletion of Kupffer cells abrogated both quantitative and qualitative methionine-and-choline deficient (MCD)-induced alterations in hepatic lipids. Interestingly, mimicking inflammatory events in early hepatocarcinogenesis by diethylnitrosamine-induced carcinogenesis (48 h) increased hepatic lipids and the C18/C16 ratio. Analyses of human liver samples from patients with NASH or NASH-related HCC showed an elevated expression of the elongase ELOVL6, which is responsible for the elongation of C16 fatty acids. Taken together, our findings suggest a detrimental role of an altered fatty acid pattern in the progression of NASH-related liver disease.
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Affiliation(s)
- Sonja M Kessler
- Department of Pharmacy, Pharmaceutical Biology, Saarland University, Campus C2 2, 66123 Saarbrücken, Germany.
| | - Yvette Simon
- Department of Pharmacy, Pharmaceutical Biology, Saarland University, Campus C2 2, 66123 Saarbrücken, Germany.
| | - Katja Gemperlein
- Department of Pharmacy, Pharmaceutical Biotechnology, Saarland University and Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.
| | - Kathrin Gianmoena
- Systems Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo) at the TU Dortmund, Ardeystr. 67, 44139 Dortmund, Germany.
| | - Cristina Cadenas
- Systems Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo) at the TU Dortmund, Ardeystr. 67, 44139 Dortmund, Germany.
| | - Vincent Zimmer
- Department of Medicine II, Saarland University Medical Center, Kirrberger Str., 66421 Homburg, Germany.
| | - Juliane Pokorny
- Institute of Pathology, Saarland University, Kirrberger Str., 66421 Homburg, Germany.
| | - Ahmad Barghash
- Center for Bioinformatics, Saarland University, Campus E2 1, 66123 Saarbrücken, Germany.
| | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Campus E2 1, 66123 Saarbrücken, Germany.
| | - Nico van Rooijen
- Department of Molecular Cell Biology, Faculty of Medicine, Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
| | - Rainer M Bohle
- Institute of Pathology, Saarland University, Kirrberger Str., 66421 Homburg, Germany.
| | - Frank Lammert
- Department of Medicine II, Saarland University Medical Center, Kirrberger Str., 66421 Homburg, Germany.
| | - Jan G Hengstler
- Systems Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo) at the TU Dortmund, Ardeystr. 67, 44139 Dortmund, Germany.
| | - Rolf Mueller
- Department of Pharmacy, Pharmaceutical Biotechnology, Saarland University and Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany.
| | - Johannes Haybaeck
- Institute of Pathology, Medical University of Graz, 8010 Graz, Austria.
| | - Alexandra K Kiemer
- Department of Pharmacy, Pharmaceutical Biology, Saarland University, Campus C2 2, 66123 Saarbrücken, Germany.
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11
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Abstract
Persistent infection with hepatitis C virus (HCV) is a major risk toward development of hepatocellular carcinoma (HCC). However, it remains controversial in the pathogenesis of HCC associated with HCV whether the virus plays a direct or an indirect role. The observation that chronic hepatitis C patients with sustained high levels of serum alanine aminotransferase are prone to develop HCC suggests the significance of inflammation in hepatocarcinogenesis in hepatitis C. However, the rare development of HCC in patients with autoimmune hepatitis, which is accompanied by robust inflammation, even after the progress into cirrhosis, implies a possibility of the direct role of HCV in HCC development. What is the role of HCV, a simple plus-stranded RNA virus, whose genome is never integrated into the host genome, in hepatocarcinogenesis? The studies using transgenic mouse and cultured cell models, in which the HCV proteins are expressed, indicate the direct pathogenicity of HCV, including oncogenic activities. In particular, the core protein of HCV induces overproduction of oxidative stress by impairing the mitochondrial electron transfer system, through insulting the function of molecular chaperon, prohibitin. HCV also modulates the intracellular signaling pathways including mitogen-activated protein kinase, leading to the acquisition of growth advantage by hepatocytes. In addition, HCV induces disorders in lipid and glucose metabolisms, thereby accelerating the progression of liver fibrosis and HCC development. These results would provide a clue for further understanding of the role of HCV in pathogenesis of persistent HCV infection including hepatocarcinogenesis.
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Affiliation(s)
- Kazuhiko Koike
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan,
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12
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Hino K, Hara Y, Nishina S. Mitochondrial reactive oxygen species as a mystery voice in hepatitis C. Hepatol Res 2014; 44:123-32. [PMID: 24112394 DOI: 10.1111/hepr.12247] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/05/2013] [Accepted: 09/19/2013] [Indexed: 12/21/2022]
Abstract
There are several lines of evidence suggesting that oxidative stress is present in hepatitis C to a greater degree than in other inflammatory liver diseases and is closely related to disease progression. The main production site of reactive oxygen species (ROS) is assumed to be mitochondria, which concept is supported by evidence that hepatitis C virus (HCV) core protein is directly associated with them. The detoxification of ROS also is an important function of the cellular redox homeostasis system. These results draw our attention to how HCV-induced mitochondrial ROS production is beyond redox regulation and affects the disease progression and development of hepatocellular carcinoma (HCC) in chronic hepatitis C. On the other hand, HCV-related chronic liver diseases are characterized by metabolic alterations such as insulin resistance, hepatic steatosis and/or iron accumulation in the liver. These metabolic disorders also are relevant to the development of HCC in HCV-related chronic liver diseases. Here, we review the mechanisms by which HCV increases mitochondrial ROS production and offer new insights as to how mitochondrial ROS are linked to metabolic disorders such as insulin resistance, hepatic steatosis and hepatic iron accumulation that are observed in HCV-related chronic liver diseases.
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Affiliation(s)
- Keisuke Hino
- Department of Hepatology and Pancreatology, Kawasaki Medical School, Kurashiki, Japan
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Morita Y, Sakaguchi T, Ikegami K, Goto-Inoue N, Hayasaka T, Hang VT, Tanaka H, Harada T, Shibasaki Y, Suzuki A, Fukumoto K, Inaba K, Murakami M, Setou M, Konno H. Lysophosphatidylcholine acyltransferase 1 altered phospholipid composition and regulated hepatoma progression. J Hepatol 2013; 59:292-9. [PMID: 23567080 DOI: 10.1016/j.jhep.2013.02.030] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 02/08/2013] [Accepted: 02/18/2013] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Several lipid synthesis pathways play important roles in the development and progression of hepatocellular carcinoma (HCC), although the precise molecular mechanisms remain to be elucidated. Here, we show the relationship between HCC progression and alteration of phospholipid composition regulated by lysophosphatidylcholine acyltransferase (LPCAT). METHODS Molecular lipidomic screening was performed by imaging mass spectrometry (IMS) in 37 resected HCC specimens. RT-PCR and Western blotting were carried out to examine the mRNA and protein levels of LPCATs, which catalyze the conversion of lysophosphatidylcholine (LPC) into phosphatidylcholine (PC) and have substrate specificity for some kinds of fatty acids. We examined the effect of LPCAT1 overexpression or knockdown on cell proliferation, migration, and invasion in HCC cell lines. RESULTS IMS revealed the increase of PC species with palmitoleic acid or oleic acid at the sn-2-position and the reduction of LPC with palmitic acid at the sn-1-position in HCC tissues. mRNA and protein of LPCAT1, responsible for LPC to PC conversion, were more abundant in HCCs than in the surrounding parenchyma. In cell line experiments, LPCAT1 overexpression enriched PCs observed in IMS and promoted cell proliferation, migration, and invasion. LPCAT1 knockdown did viceversa. CONCLUSIONS Enrichment or depletion of some specific PCs, was found in HCC by IMS. Alteration of phospholipid composition in HCC would affect tumor character. LPCAT1 modulates phospholipid composition to create favorable conditions to HCC cells. LPCAT1 is a potent target molecule to inhibit HCC progression.
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Affiliation(s)
- Yoshifumi Morita
- Second Department of Surgery, Hamamatsu University School of Medicine, Japan
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14
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Deletion of Nrf2 leads to rapid progression of steatohepatitis in mice fed atherogenic plus high-fat diet. J Gastroenterol 2013; 48:620-32. [PMID: 22972520 DOI: 10.1007/s00535-012-0659-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 08/03/2012] [Indexed: 02/04/2023]
Abstract
BACKGROUND The transcription factor nuclear factor-E2-related factor-2 (Nrf2) inhibits lipid accumulation and oxidative stress in the liver by interfering with lipogenic pathways and inducing antioxidative stress genes. METHODS The involvement of Nrf2 in defense against the development of steatohepatitis was studied in an experimental model induced by an atherogenic plus high-fat (Ath + HF) diet. Wild-type (WT) and Nrf2-null mice were fed the diet. Their specimens were analyzed for pathology as well as for the expression levels of genes involved in fatty acid metabolism and those involved via the Nrf2 transcriptional pathway. RESULTS In Nrf2-null mice fed the diet, steatohepatitis developed rapidly, leading to precirrhosis. The Ath + HF diet increased hepatic triglyceride levels and changed fatty acid composition in both mouse groups. However, oleic acid (C18:1 n-9) predominated in the livers of Nrf2-null mice. Correlating well with the pathology, the mRNA levels of the factors involved in fatty acid metabolism (Lxr, Srebp-1a, 1c, Acc-1, Fas, Scd-1, and Fatty acid transporting peptides 1, 3, 4), the inflammatory cytokine genes (Tnf-α and IL-1β), and the fibrogenesis-related genes (Tgf-β1 and α-Sma) were significantly increased in the livers of Nrf2-null mice fed the diet, compared with the levels of these factors in matched WT mice. Oxidative stress was significantly increased in the livers of Nrf2-null mice fed the diet. This change was closely associated with the decreased levels of antioxidative stress genes. CONCLUSIONS Nrf2 deletion leads to the rapid onset and progression of steatohepatitis induced by an Ath + HF diet, through both up-regulation of co-regulators of fatty acid metabolism and down-regulation of oxidative metabolism regulators in the liver.
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Machida K. Tumor-initiating stem-like cells and drug resistance: carcinogenesis through Toll-like receptors, environmental factors, and virus. Drug Deliv Transl Res 2013; 3:152-64. [PMID: 25787983 PMCID: PMC10578060 DOI: 10.1007/s13346-012-0115-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neoplasms contain distinct subpopulations of cells known as tumor-initiating stem-like cells (TICs) that have been identified as key drivers of tumor growth and malignant progression with drug resistance. Stem cells normally proliferate through self-renewing divisions in which the two daughter cells differ markedly in their proliferative potential, with one displaying the differentiation phenotypes and another retaining self-renewing activity. Therefore, understanding the molecular mechanisms of hepatocarcinogenesis will be required for the eventual development of improved therapeutic modalities for treating hepatocellular carcinoma (HCC). Hepatitis C virus (HCV) and hepatitis B virus is a major cause of HCC. Compelling epidemiologic evidence identifies obesity and alcohol as co-morbidity factors that can increase the risk of HCV patients for HCC, especially in alcoholics or obese patients. The mechanisms underlying liver oncogenesis, and how environmental factors contribute to this process, are not yet understood. The HCV-Toll-like receptor 4 (TLR4)-Nanog signaling network is established since alcohol/obesity-associated endotoxemia then activates TLR4 signaling, resulting in the induction of the stem cell marker Nanog expression and liver tumors. Liver TICs are highly sensitized to leptin and exposure of TICs to leptin increases the expression and activity of an intrinsic pluripotency-associated transcriptional network comprised of signal transducer and activator of transcription 3, SOX2, OCT4, and Nanog. Stimulation of the pluripotency network may have significant implications for hepatocellular oncogenesis via genesis and maintenance of TICs. It is important to understand how HCV induces liver cancer through genesis of TICs so that better prevention and treatment can be found. This article reviews the oncogenic pathways to generate TICs.
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Affiliation(s)
- Keigo Machida
- Department of Molecular Microbiology and Immunology, Research Center for ALPD and Cirrhosis, University of Southern California School of Medicine, 503C-HMR, Los Angeles, CA, 90033, USA,
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Miyake T, Hiasa Y, Hirooka M, Tokumoto Y, Watanabe T, Furukawa S, Ueda T, Yamamoto S, Kumagi T, Miyaoka H, Abe M, Matsuura B, Onji M. High serum palmitic acid is associated with low antiviral effects of interferon-based therapy for hepatitis C virus. Lipids 2012; 47:1053-62. [PMID: 22983804 DOI: 10.1007/s11745-012-3716-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 08/27/2012] [Indexed: 01/01/2023]
Abstract
Hepatitis C virus (HCV) infection alters fatty acid synthesis and metabolism in association with HCV replication. The present study examined the effect of serum fatty acid composition on interferon (IFN)-based therapy. Fifty-five patients with HCV were enrolled and received IFN-based therapy. Patient characteristics, laboratory data (including fatty acids), and viral factors that could be associated with the anti-HCV effects of IFN-based therapy were evaluated. The effects of individual fatty acids on viral replication and IFN-based therapy were also examined in an in-vitro system. Multivariate logistic regression analysis showed that the level of serum palmitic acid before treatment and HCV genotype were significant predictors for rapid virological response (RVR), early virological response (EVR), and sustained virological response (SVR). High levels of palmitic acid inhibited the anti-HCV effects of IFN-based therapy. HCV replication assays confirmed the inhibitory effects of palmitic acid on anti-HCV therapy. The concentration of serum palmitic acid is an independent predictive factor for RVR, EVR, and SVR in IFN-based antiviral therapy. These results suggest that the effect of IFN-based antiviral therapy in patients with HCV infection might be enhanced by treatment that modulates palmitic acid levels.
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Affiliation(s)
- Teruki Miyake
- Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan
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Eslam M, Khattab MA, Harrison SA. Peroxisome proliferator-activated receptors and hepatitis C virus. Therap Adv Gastroenterol 2011; 4:419-31. [PMID: 22043232 PMCID: PMC3187680 DOI: 10.1177/1756283x11405251] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The prevalence of type 2 diabetes mellitus and insulin resistance are higher among people chronically infected with hepatitis C (CHC) when compared with the general population and people with other causes of chronic liver disease. Both insulin resistance and diabetes are associated with adverse outcomes across all stages of CHC, including the liver transplant population. CHC is also associated with the development of hepatic steatosis, a common histological feature present in approximately 55% (32-81%) of cases. There is a complex interrelationship between insulin resistance and hepatic steatosis and both are postulated to aggravate each other. The peroxisome proliferator-activated receptors (PPARs) are nuclear factors involved in the regulation of glucose, lipid homeostasis, inflammatory response, cell differentiation, and cell cycle. The relationship between hepatitis C virus replication and PPARs has been the focus of recent study. Given the availability of potent agonists, PPARs may represent a novel pharmacological target in the treatment of CHC.
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Affiliation(s)
- M. Eslam
- Department of Internal Medicine, Minia University, Minia, Egypt
| | - M. A. Khattab
- Department of Internal Medicine, Minia University, Minia, Egypt
| | - S. A. Harrison
- Division of Gastroenterology and Hepatology, Department of Medicine, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, TX 78234, USA
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Lerat H, Higgs M, Pawlotsky JM. Animal models in the study of hepatitis C virus-associated liver pathologies. Expert Rev Gastroenterol Hepatol 2011; 5:341-52. [PMID: 21651352 DOI: 10.1586/egh.11.14] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It is estimated that more than 170 million individuals worldwide are chronically infected with hepatitis C virus (HCV), with approximately 20% of the cases developing cirrhosis. Each year, between 1 and 4% of patients exhibiting cirrhosis develop hepatocellular carcinoma. Chronic HCV infection is also linked with the development of several metabolic disorders, including hepatic steatosis and insulin resistance. Research into HCV-related pathologies is hampered by a relative paucity of small animal models. As a result, little is known about the molecular mechanisms involved, and much of our current knowledge is drawn by inference from in vitro studies using overexpressed proteins. In this article, we will review the currently available animal models for the study of HCV pathogenesis, with an emphasis on murine models. Then, we will provide an overview of how these models have contributed to the deciphering of the molecular mechanisms underlying dysregulated lipid metabolism and hepatocellular carcinoma during HCV infection.
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Affiliation(s)
- Hervé Lerat
- Institut National de la Santé et de la Recherche Médicale, Unité U955, Université Paris-Est, Créteil, F-94010, France.
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Miyoshi H, Moriya K, Tsutsumi T, Shinzawa S, Fujie H, Shintani Y, Fujinaga H, Goto K, Todoroki T, Suzuki T, Miyamura T, Matsuura Y, Yotsuyanagi H, Koike K. Pathogenesis of lipid metabolism disorder in hepatitis C: polyunsaturated fatty acids counteract lipid alterations induced by the core protein. J Hepatol 2011; 54:432-8. [PMID: 21093950 DOI: 10.1016/j.jhep.2010.07.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 06/08/2010] [Accepted: 07/05/2010] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Disturbance in lipid metabolism is one of the features of chronic hepatitis C, being a crucial determinant of the progression of liver fibrosis. Experimental studies have revealed that the core protein of hepatitis C virus (HCV) induces steatosis. METHODS The activities of fatty acid metabolizing enzymes were determined by analyzing the fatty acid compositions in HepG2 cells with or without core protein expression. RESULTS There was a marked accumulation of triglycerides in core-expressing HepG2 cells. While the oleic/stearic acid (18:1/18:0) and palmitoleic/palmitic acid ratio (16:1/16:0) were comparable in both the core-expressing and the control cells, there was a marked accumulation of downstream product, 5,8,11-eicosatrienoic acid (20:3(n-9)) in the core-expressing HepG2 cells. The addition of eicosatetraynoic acid, which inhibits delta-6 desaturase activity which is inherently high in HepG2 cells, led to a marked accumulation of oleic and palmitoleic acids in the core-expressing cells, showing that delta-9 desaturase was activated by the core protein. Eicosapentaenoic acid (20:5(n-3)) or arachidonic acid (20:4(n-6)) administration significantly decreased delta-9 desaturase activity, the concentration of 20:3(n-9), and triglyceride accumulation. This lipid metabolism disorder was associated with NADH accumulation due to mitochondrial dysfunction, and was reversed by the addition of pyruvate through NADH utilization. CONCLUSIONS The fatty acid enzyme, delta-9 desaturase, was activated by HCV core protein and polyunsaturated fatty acids counteracted this impact of the core protein on lipid metabolism. These results may open up new insights into the mechanism of lipid metabolism disorder associated with HCV infection and provide clues for the development of new therapeutic devices.
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Affiliation(s)
- Hideyuki Miyoshi
- Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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Ogiyama H, Kamada Y, Kiso S, Araki H, Yamada T, Nishihara T, Watabe K, Tochino Y, Kihara S, Funahashi T, Kanno K, Shimomura I, Tsutsui S, Tazuma S, Hayashi N. Lack of adiponectin promotes formation of cholesterol gallstones in mice. Biochem Biophys Res Commun 2010; 399:352-8. [DOI: 10.1016/j.bbrc.2010.07.075] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 07/21/2010] [Indexed: 01/12/2023]
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Tachi Y, Katano Y, Honda T, Hayashi K, Ishigami M, Itoh A, Hirooka Y, Nakano I, Samejima Y, Goto H. Impact of amino acid substitutions in the hepatitis C virus genotype 1b core region on liver steatosis and hepatic oxidative stress in patients with chronic hepatitis C. Liver Int 2010; 30:554-9. [PMID: 19951380 DOI: 10.1111/j.1478-3231.2009.02164.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Liver steatosis and hepatic oxidative stress are the histopathological features of chronic hepatitis C. Hepatitis C virus (HCV) genotype 1 core protein induces hepatic steatosis and reactive oxygen species production in transgenic mice. The amino acid substitutions in the HCV core region appear to be related to hepatocarcinogenesis. AIMS The aim of this study was to clarify the impact of mutations in the HCV core region on oxidative stress and lipid metabolism in patients with chronic hepatitis C. METHODS Sixty-seven patients (35 men, 32 women; mean age, 58.4 +/- 10.2 years) with chronic hepatitis C with high titres (>5 log IU/ml) were enrolled. Substitutions in amino acids 70, 75 and 91 of the HCV genotype 1b core region, the percentage of hepatic steatosis, and hepatic 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were investigated in all patients. Urinary 8-OHdG levels were measured in 35 patients. RESULTS Body mass index, alanine aminotransferase, gamma-glutamyl transferase, and triglyceride levels and substitutions of amino acid 70/Q (glutamine) were significantly associated with the presence of steatosis on univariate analysis. Multivariate analysis showed that substitution of amino acid 70 of glutamine and triglyceride levels were the independent factors related to liver steatosis. Hepatic and urinary 8-OHdG levels were significantly higher in patients with methionine at amino acid 91 of the HCV core region than in those with leucine. CONCLUSION Substitutions in the amino acids of the HCV genotype1b core region are associated with hepatic steatosis and oxidative stress in patients with chronic hepatitis C.
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Affiliation(s)
- Yoshihiko Tachi
- Department of Gastroenterology, Nagoya University School of Medicine, Nagoya, Aichi, Japan
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Abstract
Persistent infection with hepatitis C virus (HCV) is a major risk toward development of hepatocellular carcinoma (HCC). The elucidation of pathogenesis of HCV-associated liver disease is hampered by the absence of appropriate animal models: there has been no animal model for HCV infection/pathogenesis except for the chimpanzee. In contrast, a number of transgenic mouse lines carrying the cDNA of the HCV genome have been established and evaluated in the study of HCV pathogenesis. The studies using transgenic mouse models, in which the HCV proteins such as the core protein are expressed, indicate the direct pathogenicity of HCV, including oncogenic activities. HCV transgenic mouse models also show a close relationship between HCV and some hepatic and extrahepatic manifestations such as hepatic steatosis, insulin resistance or Sjögren's syndrome. A crucial role of hepatic steatosis and insulin resistance in the pathogenesis of liver disease in HCV infection has been demonstrated, implying hepatitis C to be a metabolic disease. Besides the data connecting liver fibrosis progression and the disturbance in lipid and glucose metabolisms in hepatitis C patients, a series of evidence was found showing the association between these two conditions and HCV infection, chiefly using transgenic mouse carrying the HCV genome. Furthermore, the persistent activation of peroxisome proliferator-activated receptor (PPAR)-alpha has recently been found, yielding dramatic changes in the lipid metabolism and oxidative stress overproduction in cooperation with the mitochondrial dysfunction. These results would provide a clue for further understanding of the role of lipid metabolism in pathogenesis of hepatitis C including liver injury and hepatocarcinogenesis.
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Affiliation(s)
- Kazuhiko Koike
- Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo
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Moriya K, Miyoshi H, Tsutsumi T, Shinzawa S, Fujie H, Shintani Y, Yotsuyanagi H, Moriishi K, Matsuura Y, Suzuki T, Miyamura T, Koike K. Tacrolimus ameliorates metabolic disturbance and oxidative stress caused by hepatitis C virus core protein: analysis using mouse model and cultured cells. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1515-24. [PMID: 19729476 DOI: 10.2353/ajpath.2009.090102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hepatic steatosis and insulin resistance are factors that aggravate the progression of liver disease caused by hepatitis C virus (HCV) infection. In the pathogenesis of liver disease and metabolic disorders in HCV infection, oxidative stress due to mitochondrial respiratory chain dysfunction plays a pivotal role. Tacrolimus (FK506) is supposed to protect mitochondrial respiratory function. We studied whether tacrolimus affects the development of HCV-associated liver disease using HCV core gene transgenic mice, which develop hepatic steatosis, insulin resistance, and hepatocellular carcinoma. Administration of tacrolimus to HCV core gene transgenic mice three times per week for 3 months led to a significant reduction in the amounts of lipid in the liver as well as in serum insulin. Tacrolimus treatment also ameliorated oxidative stress and DNA damage in the liver of the core gene transgenic mice. Tacrolimus administration reproduced these effects in a dose-dependent manner in HepG2 cells expressing the core protein. The intrahepatic level of tumor necrosis factor-alpha, which may be a key molecule for the pathogenesis in HCV infection, was significantly decreased in tacrolimus-treated core gene transgenic mice. Tacrolimus thus reversed the effect of the core protein in the pathogenesis of HCV-associated liver disease. These results may provide new therapeutic tools for chronic hepatitis C, in which oxidative stress and abnormalities in lipid and glucose metabolism contribute to liver pathogenesis.
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Affiliation(s)
- Kyoji Moriya
- Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan
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Tsutsumi T, Matsuda M, Aizaki H, Moriya K, Miyoshi H, Fujie H, Shintani Y, Yotsuyanagi H, Miyamura T, Suzuki T, Koike K. Proteomics analysis of mitochondrial proteins reveals overexpression of a mitochondrial protein chaperon, prohibitin, in cells expressing hepatitis C virus core protein. Hepatology 2009; 50:378-86. [PMID: 19591124 DOI: 10.1002/hep.22998] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED The hepatitis C virus (HCV) core protein is involved in viral pathogenesis such as oxidative stress induction and lipid metabolism disturbance, and is primarily located in the cytoplasm and endoplasmic reticulum in association with lipid droplets as well as in the mitochondria. To clarify the impact of the core protein on mitochondria, we analyzed the expression pattern of mitochondrial proteins in core protein-expressing cells by two-dimensional polyacrylamide gel electrophoresis. Several proteins related to the mitochondrial respiratory chain or protein chaperons were identified by mass spectrometry. Among the identified proteins with consistently different expressions, prohibitin, a mitochondrial protein chaperon, was up-regulated not only in core-expressing cells but also in full-genomic replicon cells and livers of core-gene transgenic mice. The stability of prohibitin was increased through interaction with the core protein. Further analysis demonstrated that interaction of prohibitin with mitochondrial DNA-encoded subunits of cytochrome c oxidase (COX) was disturbed by the core protein, resulting in a significant decrease in COX activity. CONCLUSION The HCV core protein affects the steady-state levels of a subset of mitochondrial proteins including prohibitin, which may lead to an impaired function of the mitochondrial respiratory chain with the overproduction of oxidative stress.
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Affiliation(s)
- Takeya Tsutsumi
- Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Japan
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Fukushima J, Kamada Y, Matsumoto H, Yoshida Y, Ezaki H, Takemura T, Saji Y, Igura T, Tsutsui S, Kihara S, Funahashi T, Shimomura I, Tamura S, Kiso S, Hayashi N. Adiponectin prevents progression of steatohepatitis in mice by regulating oxidative stress and Kupffer cell phenotype polarization. Hepatol Res 2009; 39:724-38. [PMID: 19473437 DOI: 10.1111/j.1872-034x.2009.00509.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM We reported previously that hypoadiponectinemia enhances hepatic oxidative stress and accelerates progression of nonalcoholic steatohepatitis (NASH) in mice. However, the precise mechanism and preventive effects of adiponectin on NASH remain unclear. The aim of this study was to examine the effects of adiponectin on steatohepatitis using adiponectin-knockout (KO) mice and adenovirus-mediated adiponectin expression system. METHODS We used male KO mice and C57BL6/J (WT) mice fed methionine choline-deficient (MCD)-diet as a steatohepatitis model. Liver histology, hepatic oxidative stress markers, and hepatic gene expression levels were investigated. In addition, Hepa 1-6 cells, a mouse liver cell line, were cultured with or without recombinant adiponectin, and gene expressions were investigated by real-time RT-PCR. RESULTS After 2-week feeding of MCD diet, hepatic steatosis was enhanced and plasma alanine aminotransferase elevated in KO mice than in WT mice. In KO mice liver, thiobarbituric acid reactive substances increased, glutathione levels decreased, and mRNA expression levels of antioxidant enzymes (catalase, superoxide dismutase-1) downregulated. Adenovirus-mediated adiponectin expression prevented these changes in KO mice. Moreover, Kupffer cell infiltration was enhanced and mRNA levels of anti-inflammatory M2 macrophage markers (interleukin-10, arginase-1) were decreased in KO mice liver. In the in vitro study, adiponectin significantly increased catalase gene expression in Hepa 1-6 cells. CONCLUSIONS Lack of adiponectin enhanced, and adiponectin administration prevented steatohepatitis progression in mice. These changes were due to the anti-oxidative effects of adiponectin, and its effects on Kupffer cells recruitment and phenotype polarization. Augmentation of adiponectin effects could be a useful preventive approach for NASH progression.
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Affiliation(s)
- Juichi Fukushima
- Department of Gastroenterology, Osaka University Graduate School of Medicine, Suita, Japan
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Anezaki Y, Ohshima S, Ishii H, Kinoshita N, Dohmen T, Kataoka E, Sato W, Iizuka M, Goto T, Sasaki J, Sasaki T, Suzuki A, Ohnishi H, Horie Y. Sex difference in the liver of hepatocyte-specific Pten-deficient mice: A model of nonalcoholic steatohepatitis. Hepatol Res 2009; 39:609-18. [PMID: 19527485 DOI: 10.1111/j.1872-034x.2009.00494.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIM Nonalcoholic fatty liver disease (NAFLD) is considered to be a public health problem worldwide. NAFLD is more prevalent in men than in women. Tamoxifen, a potent estrogen receptor antagonist, causes nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. Thus, there may be a sex difference that is dependent on estrogens in NAFLD and NASH. Hepatocyte-specific Pten-deficient mice exhibit hepatic lesions analogous to NASH and are considered to be a clinical model of NASH. We aimed to shed light on any sex differences in the hepatic lesions of Pten-deficient mice and the underlying mechanisms. METHODS At 40 weeks, livers from male and female Pten-deficient mice were processed for measuring lipid content, genes expression analysis, and histological examination. Level of serum reactive oxygen species (ROS) was also determined. Seventy-six-week-old mice were used in tumor burden experiments. RESULTS Hepatic steatosis, inflammation, and even carcinogenesis in Pten-deficient mice were attenuated in females compared to males. Attenuated fatty liver in females was ascribed to inactivation of sterol regulatory element binding protein-1c. Hepatic inflammation in females was suppressed via decreased ROS with increased antioxidant gene expression and decreased proinflammatory cytokine production. Anti-cancer effect in female mice was, at least in part, due to the significantly lower ratio of oleic to stearic acid in the liver. CONCLUSIONS Hepatic lesions in Pten-deficient mice were attenuated in females compared to males, as were human NAFLD and NASH. Some of the underlying mechanisms in sex difference appeared to be due to the change of gene expression, dependent on estrogens.
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Affiliation(s)
- Yumiko Anezaki
- Department of Gastroenterology, Akita University School of Medicine, Akita, Japan
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Koike K. Steatosis, liver injury, and hepatocarcinogenesis in hepatitis C viral infection. J Gastroenterol 2009; 44 Suppl 19:82-8. [PMID: 19148799 DOI: 10.1007/s00535-008-2276-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 08/10/2008] [Indexed: 02/04/2023]
Abstract
In addition to the link with development of hepatocellular carcinoma (HCC), hepatitis C virus (HCV) infection is associated with several hepatic and extrahepatic manifestations. A role of hepatic steatosis in the pathogenesis of chronic hepatitis C has been shown, implying hepatitis C as a metabolic disease. Furthermore, recent epidemiological studies have suggested a linkage between insulin resistance and chronic HCV infection. In addition to the data indicating the presence of lipid metabolism disturbance and insulin resistance in the cohort of chronic hepatitis C patients, we found evidence showing the association between these two conditions and HCV infection using mice transgenic for the HCV core gene. These mice develop HCC late in life after the phase of hepatic steatosis and insulin resistance. The nonappearance of both steatosis and HCC in HCV core gene transgenic mice that are null for the proteasome activator 28gamma implies a close relationship between lipid metabolism disturbance and hepatocarcinogenesis. Also, the core protein is shown to bind with retinoid X receptor (RXR)-alpha, resulting in the upregulation of some lipid metabolism enzymes, including cellular retinol binding protein II and acyl-CoA oxidase. In addition, the persistent activation of peroxisome proliferator activated receptor (PPAR)-alpha has recently been found in the liver of HCV core gene transgenic mice, yielding dramatic changes in lipid metabolism and hepatocyte proliferation, including HCC development. These results would provide a clue for further understanding of the role of lipid metabolism in pathogenesis of HCV infection, including liver injury and hepatocarcinogenesis.
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Affiliation(s)
- Kazuhiko Koike
- Department of Infectious Diseases, Internal Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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Ishii H, Horie Y, Ohshima S, Anezaki Y, Kinoshita N, Dohmen T, Kataoka E, Sato W, Goto T, Sasaki J, Sasaki T, Watanabe S, Suzuki A, Ohnishi H. Eicosapentaenoic acid ameliorates steatohepatitis and hepatocellular carcinoma in hepatocyte-specific Pten-deficient mice. J Hepatol 2009; 50:562-71. [PMID: 19162361 DOI: 10.1016/j.jhep.2008.10.031] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 09/20/2008] [Accepted: 10/08/2008] [Indexed: 12/19/2022]
Abstract
BACKGROUND/AIMS Eicosapentaenoic acid (EPA) has been known as a reagent for improving lipid metabolism and inflammation. Hepatocyte-specific Pten-deficient mice exhibit hepatic lesions analogous to non-alcoholic steatohepatitis (NASH). Therefore, we administered EPA to Pten-deficient mice to investigate the mechanisms of NASH. METHODS Pten-deficient mice were assigned to a control group fed with a standard chow or an EPA group fed with a 5% EPA-supplemented standard chow. At 40 weeks, livers from each group were processed to measure triglyceride content, gene expression analysis, Western blotting analysis, and histological examination. Level of serum reactive oxygen species (ROS) was also determined. Forty- and 76-week-old mice were used in tumor burden experiments. RESULTS EPA-ameliorated hepatic steatosis in Pten-deficient mice was based on decreased expression of AMPKalpha1-mediated SREBP-1c and increased PPARalpha expression. The EPA group exhibited less severe chronic hepatic inflammation compared to the control group, resulting from decreased ROS formation and a dramatically low ratio of arachidonic acid to EPA. Moreover, EPA inhibited development of hepatocellular carcinoma (HCC) in Pten-deficient mice based on an inhibition of MAPK activity and a low ratio of oleic to stealic acid, and a reduction in ROS formation. CONCLUSIONS EPA ameliorated steatohepatitis and development of HCC in Pten-deficient mice.
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Affiliation(s)
- Hajime Ishii
- Department of Gastroenterology, Akita University School of Medicine, Akita, Japan
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Mohan KV, Muller J, Atreya CD. Defective rotavirus particle assembly in lovastatin-treated MA104 cells. Arch Virol 2008; 153:2283-90. [PMID: 19030953 PMCID: PMC7087225 DOI: 10.1007/s00705-008-0261-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 10/27/2008] [Indexed: 11/05/2022]
Abstract
Rotavirus is a non-enveloped virus that depends on cellular lipids for cell entry and associates with lipid rafts during assembly. However, the effects of cellular lipids on rotavirus assembly are still not fully understood. The present study analyzes the effects of lovastatin, an inhibitor of cholesterol biosynthesis, during rotavirus infection in MA104 cells with regard to viral growth and particle assembly. Following viral infection, a 2-log relative reduction of viral titers was observed in drug-treated cells, while viral mRNA levels in infected cells remained unaltered in both groups. Furthermore, the levels of some viral proteins in drug-treated cells were elevated. The observed discordance between the viral RNA and protein levels and the decrease in infectivity titers of viral progeny in the drug-treated cells suggested that the drug affects viral assembly, the viral proteins not being properly incorporated into virions. Transmission electron microscopic (TEM) analysis revealed that in drug-treated cells there was an increase in “empty-looking” rotavirus particles devoid of an electron-dense core as compared to the normal, electron-dense particles seen in untreated infected cells. The present study thus provides visual evidence of defective rotavirus particle assembly as a result of cholesterol depletion.
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Affiliation(s)
- Ketha V Mohan
- Laboratory of Hepatitis Viruses, Food and Drug Administration, Bethesda, MD 20892, USA.
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31
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Abstract
Primary liver cancer is the sixth most common cancer in the world and the third most common cause of death attributable to cancer. Most primary liver cancers are hepatocellular carcinoma (HCC), accounting for 85% to 90% of cases. There is a trend of growing incidence of HCC in the United States. One of the most important risk factors for developing HCC is chronic hepatitis C virus (HCV) infection. Although several studies suggested the preventive effect of interferon from developing HCC in HCV-infected individuals, these findings need to be validated in large prospective and randomized trials.
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Affiliation(s)
- Wojciech Blonski
- Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
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32
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Abstract
Hepatocellular carcinoma (HCC) is a common and deadly cancer whose pathogenesis is incompletely understood. Comparative genomic studies from human HCC samples have classified HCCs into different molecular subgroups; yet, the unifying feature of this tumor is its propensity to arise upon a background of inflammation and fibrosis. This review seeks to analyze the available experimental models in HCC research and to correlate data from human populations with them in order to consolidate our efforts to date, as it is increasingly clear that different models will be required to mimic different subclasses of the neoplasm. These models will be instrumental in the evaluation of compounds targeting specific molecular pathways in future preclinical studies.
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Tanaka N, Moriya K, Kiyosawa K, Koike K, Gonzalez FJ, Aoyama T. PPARalpha activation is essential for HCV core protein-induced hepatic steatosis and hepatocellular carcinoma in mice. J Clin Invest 2008; 118:683-94. [PMID: 18188449 DOI: 10.1172/jci33594] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 11/07/2007] [Indexed: 02/06/2023] Open
Abstract
Transgenic mice expressing HCV core protein develop hepatic steatosis and hepatocellular carcinoma (HCC), but the mechanism underlying this process remains unclear. Because PPARalpha is a central regulator of triglyceride homeostasis and mediates hepatocarcinogenesis in rodents, we determined whether PPARalpha contributes to HCV core protein-induced diseases. We generated PPARalpha-homozygous, -heterozygous, and -null mice with liver-specific transgenic expression of the core protein gene (Ppara(+/+):HCVcpTg, Ppara(+/-):HCVcpTg, and Ppara(-/-):HCVcpTg mice. Severe steatosis was unexpectedly observed only in Ppara(+/+):HCVcpTg mice, which resulted from enhanced fatty acid uptake and decreased mitochondrial beta-oxidation due to breakdown of mitochondrial outer membranes. Interestingly, HCC developed in approximately 35% of 24-month-old Ppara(+/+):HCVcpTg mice, but tumors were not observed in the other genotypes. These phenomena were found to be closely associated with sustained PPARalpha activation. In Ppara(+/-):HCVcpTg mice, PPARalpha activation and the related changes did not occur despite the presence of a functional Ppara allele. However, long-term treatment of these mice with clofibrate, a PPARalpha activator, induced HCC with mitochondrial abnormalities and hepatic steatosis. Thus, our results indicate that persistent activation of PPARalpha is essential for the pathogenesis of hepatic steatosis and HCC induced by HCV infection.
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Affiliation(s)
- Naoki Tanaka
- Department of Metabolic Regulation, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan.
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Koike K, Tsutsumi T, Miyoshi H, Shinzawa S, Shintani Y, Fujie H, Yotsuyanagi H, Moriya K. Molecular basis for the synergy between alcohol and hepatitis C virus in hepatocarcinogenesis. J Gastroenterol Hepatol 2008; 23 Suppl 1:S87-91. [PMID: 18336672 DOI: 10.1111/j.1440-1746.2007.05292.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Overwhelming lines of epidemiological evidence have indicated that persistent infection with hepatitis C virus (HCV) is a major risk for the development of hepatocellular carcinoma (HCC). In addition, heavy alcohol use has been linked with earlier progression to HCC in chronic hepatitis C patients. However, in the pathogenesis of HCV-associated HCC, it still remains controversial as to whether the virus plays a direct or an indirect role, and as to how alcohol operates in the acceleration of HCC development. Several studies using transgenic mouse models, in which the core protein of HCV has an oncogenic potential, indicate that HCV is directly involved in hepatocarcinogenesis, although other factors such as continuous inflammation or environmental factors seem also to play a role. The downstream events of the HCV core protein expression in the transgenic mouse HCC model are segregated into two pathways. One is the augmented production of oxidative stress in the absence of inflammation along with the attenuation of some scavenging systems in the putative preneoplastic stage with steatosis in the liver. The other pathway is the alteration in cellular gene expression and intracellular signaling, including the mitogen-activated protein kinase cascade. The combination of these pathways would explain the unusually high incidence and multicentric nature of HCC development in HCV infection. In addition, alcohol feeding in this animal model further activated the two pathways synergistically with HCV, leading to an earlier development of HCC. Such a synergy would reveal the molecular basis for the acceleration of HCC development by alcohol in HCV infection.
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Affiliation(s)
- Kazuhiko Koike
- Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
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Jhaveri R, McHutchison J, Patel K, Qiang G, Diehl AM. Specific polymorphisms in hepatitis C virus genotype 3 core protein associated with intracellular lipid accumulation. J Infect Dis 2008; 197:283-91. [PMID: 18177246 DOI: 10.1086/524846] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Steatosis is a common histological finding and a poor prognostic indicator in patients with hepatitis C virus (HCV) infection. In HCV genotype 3-infected patients, the etiology of steatosis appears to be closely correlated with unknown viral factors that increase intracellular lipid levels. We hypothesize that specific sequence polymorphisms in HCV genotype 3 core protein may be associated with hepatic intracellular lipid accumulation. METHODS Using selected serum samples from 8 HCV genotype 3-infected patients with or without steatosis, we sequenced the HCV core gene to identify candidate polymorphisms associated with increased intracellular lipid levels. RESULTS Two polymorphisms at positions 182 and 186 of the core protein correlated with the presence (P= .03) and absence (P= .005) of intrahepatic steatosis. Transfected liver cell lines expressing core protein with steatosis-associated polymorphisms had increased intracellular lipid levels compared with non-steatosis-associated core isolates, as measured by oil red O staining (P= .02). Site-specific mutagenesis performed at positions 182 and 186 in steatosis-associated core genes yielded proteins that had decreased intracellular lipid levels in transfected cells (P= .03). CONCLUSIONS We have identified polymorphisms in HCV core protein genotype 3 that produce increased intracellular lipid levels and thus may play a significant role in lipid metabolism or trafficking, contributing to steatosis.
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Affiliation(s)
- Ravi Jhaveri
- Division of Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Abstract
Hepatitis C virus (HCV) infects approximately 170 million people worldwide including 2 million in Japan and induces serious chronic hepatitis that results in the development of steatosis, cirrhosis and ultimately hepatocellular carcinoma. The current combination therapy using pegylated interferon alpha and a nucleotide analogue ribavirin achieved a sustained virological response in about half population of individuals infected with HCV genotypes la and lb. More than two-thirds of the HCV-positive population has been chronically infected with genotype 1 in Western countries and Japan. Therefore, more effective therapeutics and preventative measures are needed for the treatment of hepatitis C patients who are not responsive to the current chemotherapy. HCV core protein is well known to be the viral capsid protein as well as the pathogenic factor that induces steatosis and hepatocellular carcinoma in the transgenic mice. In this review, we summarize the current status of our knowledge regarding the molecular mechanism by which HCV core protein induces liver steatosis and hepatocellular carcinoma and discuss on a future perspective for the development of novel therapeutics for chronic hepatitis C.
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Affiliation(s)
- Kohji Moriishi
- Department of Molecular Virology Research Institute for Microbial Diseases, Osaka University 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
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Kamada Y, Matsumoto H, Tamura S, Fukushima J, Kiso S, Fukui K, Igura T, Maeda N, Kihara S, Funahashi T, Matsuzawa Y, Shimomura I, Hayashi N. Hypoadiponectinemia accelerates hepatic tumor formation in a nonalcoholic steatohepatitis mouse model. J Hepatol 2007; 47:556-64. [PMID: 17459514 DOI: 10.1016/j.jhep.2007.03.020] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 02/14/2007] [Accepted: 03/05/2007] [Indexed: 12/20/2022]
Abstract
BACKGROUND/AIMS Adipose tissue produces a number of adipocytokines, including adiponectin, leptin, and tumor necrosis factor-alpha. Obesity, which is associated with low plasma adiponectin levels, is an independent risk factor for various liver diseases including nonalcoholic steatohepatitis (NASH). The aim of this study was to examine the effects of adiponectin on the progression of NASH to cirrhosis and tumor formation using adiponectin-knockout (KO) mice. METHODS Using a choline-deficient L-amino acid-defined (CDAA) diet-induced mouse NASH model, liver histology and oxidative stress markers were investigated in KO and wild-type (WT) mice. RESULTS Hepatic steatosis was enhanced to a greater extent in KO mice, compared to WT mice after a 1-week CDAA diet. After 24 weeks, 6 out of 14 KO mice developed liver cirrhosis and hepatic tumors, whereas the 15 WT mice showed only simple steatosis. In KO mice, hepatic cytochrome P450 2E1 levels were upregulated, and markers of oxidative stress (thiobarbituric acid reactive substances, 8-hydroxydeoxyguanosine-positive cells) were significantly increased compared with WT mice. CONCLUSIONS Our results indicate that lack of adiponectin enhances the progression of hepatic steatosis, fibrosis, and hepatic tumor formation in an animal model of NASH. Hypoadiponectinemia in obesity could be a risk factor for NASH-related hepatic tumor formation.
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Affiliation(s)
- Yoshihiro Kamada
- Department of Gastroenterology and Hepatology, Osaka University, Graduate School of Medicine, 2-2, K1, Yamada-oka, Suita, Osaka 565-0871, Japan
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Koike K. Pathogenesis of HCV-associated HCC: Dual-pass carcinogenesis through activation of oxidative stress and intracellular signaling. Hepatol Res 2007; 37 Suppl 2:S115-20. [PMID: 17877471 DOI: 10.1111/j.1872-034x.2007.00173.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Overwhelming lines of epidemiological evidence have indicated that persistent infection with hepatitis C virus (HCV) is a major risk toward development of hepatocellular carcinoma (HCC). It remains controversial, however, in the pathogenesis of HCC associated with HCV, whether the virus plays a direct role or merely an indirect one. The studies using transgenic mouse models by us and others, in which the core protein of HCV has oncogenic potential, indicate that HCV is directly involved in hepatocarcinogenesis, albeit other factors such as continued cell death and regeneration associated with inflammation would play a role, as well. The downstream events of the core protein are segregated into two components. One is the augmented production of oxidative stress along with the activation of scavenging system including catalase and glutathion (GSH) in the putative preneoplastic stage with steatosis in the liver. Thus, oxidative stress production in the absence of inflammation by the core protein would partly contribute to the development of HCC. The generation of oxidative stress is estimated to originate from mitochondrial dysfunction in hepatocytes by HCV infection. The other is the alteration of intracellular signaling cascade of MAPK (JNK),AP-1, cyclin D1, and CDK4. The combination of these pathways, collective with HCV-associated alterations in lipid and glucose metabolism, would lead to the frequent development of HCC in persistent HCV infection. Our results suggest that there would be a mechanism for hepatocarcinogenesis in persistent HCV infection that is distinct from those for other cancers. Similar to the pathogenesis of other cancers, the accumulation of a set of genetic aberrations may also be necessary for multistage development of HCC. However, HCV core protein, to which an oncogenic potential is ascribed, may allow some of the multiple steps to be bypassed in hepatocarcinogenesis. Therefore, unlike other cancers, HCV infection can elicit HCC in the absence of a complete set of genetic aberrations. Such a scenario, "non-Vogelstein-type" carcinogenesis, would explain the unusually high incidence and multicentric nature of HCC development in HCV infection.
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Affiliation(s)
- Kazuhiko Koike
- Department of Infectious Diseases, Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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Zou C, Ma J, Wang X, Guo L, Zhu Z, Stoops J, Eaker AE, Johnson CJ, Strom S, Michalopoulos GK, DeFrances MC, Zarnegar R. Lack of Fas antagonism by Met in human fatty liver disease. Nat Med 2007; 13:1078-85. [PMID: 17704785 DOI: 10.1038/nm1625] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Accepted: 06/28/2007] [Indexed: 12/24/2022]
Abstract
Hepatocytes in fatty livers are hypersensitive to apoptosis and undergo escalated apoptotic activity via death receptor-mediated pathways, particularly that of Fas-FasL, causing hepatic injury that can eventually proceed to cirrhosis and end-stage liver disease. Here we report that the hepatocyte growth factor receptor, Met, plays an important part in preventing Fas-mediated apoptosis of hepatocytes by sequestering Fas. We also show that Fas antagonism by Met is abrogated in human fatty liver disease (FLD). Through structure-function studies, we found that a YLGA amino-acid motif located near the extracellular N terminus of the Met alpha-subunit is necessary and sufficient to specifically bind the extracellular portion of Fas and to act as a potent FasL antagonist and inhibitor of Fas trimerization. Using mouse models of FLD, we show that synthetic YLGA peptide tempers hepatocyte apoptosis and liver damage and therefore has therapeutic potential.
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Affiliation(s)
- Chunbin Zou
- Department of Pathology, School of Medicine, University of Pittsburgh, S411A Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, Pennsylvania 15261, USA
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Ichibangase T, Moriya K, Koike K, Imai K. A Proteomics Method Revealing Disease-Related Proteins in Livers of Hepatitis-Infected Mouse Model. J Proteome Res 2007; 6:2841-9. [PMID: 17559251 DOI: 10.1021/pr070094c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this post-genome era, a sensitive quantitative method is required for differential profiling analyses of clinical proteomes to understand the disease progress. Here, we adopt the FD-LC-MS/MS method, consisting of fluorogenic derivatization (FD), separation by liquid chromatography (LC), and identification by LC-tandem mass spectrometry (MS/MS), to reveal disease-related proteins in livers of hepatocarcinogenesis in transgenic (Tg) and non-transgenic (NTg) mice at three developmental stages. After 6 months, the expression of apoptosis-related proteins is suppressed. After 12 months, proteins related to respiration, the electron-transfer system, and anti-oxidation are significantly up-regulated. After 16 months, proteins related to defense, beta-oxidation, and apoptosis are significantly suppressed. This fluctuating expression of proteins could explain the progression of hepatocarcinogenesis. The method would be useful for clinical proteomics analysis because of its high resolution, sensitivity, and reproducibility.
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Affiliation(s)
- Tomoko Ichibangase
- Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo, Japan
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Koike K. Hepatitis C virus contributes to hepatocarcinogenesis by modulating metabolic and intracellular signaling pathways. J Gastroenterol Hepatol 2007; 22 Suppl 1:S108-11. [PMID: 17567457 DOI: 10.1111/j.1440-1746.2006.04669.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Persistent infection with hepatitis C virus (HCV) is a major risk factor for development of hepatocellular carcinoma (HCC). However, it remains controversial in the pathogenesis of HCC associated with HCV as to whether the virus plays a direct or an indirect role. The studies using transgenic mouse models, in which the core protein of HCV has an oncogenic potential, indicate that HCV is directly involved in hepatocarcinogenesis, albeit other factors such as continued cell death and regeneration associated with inflammation would also play a role. The downstream events of the core protein are segregated into two components. One is the augmented production of oxidative stress along with the activation of scavenging system, including catalase and glutathione, in the putative pre-neoplastic stage with steatosis in the liver. Thus, oxidative stress production in the absence of inflammation by the core protein would partly contribute to the development of HCC. The generation of oxidative stress is estimated to originate from mitochondrial dysfunction in hepatocytes by HCV infection. The other component is the alteration of intracellular signaling cascade of mitogen-activated protein kinase and activating factor (AP)-1, leading to the activation of cell cycle control. The combination of these pathways, collective with HCV-associated alterations in lipid and glucose metabolism, would lead to the frequent development of HCC in persistent HCV infection. These results suggest that there would be a mechanism for hepatocarcinogenesis in persistent HCV infection that is distinct from those for the other cancers. Similar to the pathogenesis of other cancers, the accumulation of a set of genetic aberrations may also be necessary for a multistage development of HCC. However, HCV core protein, to which an oncogenic potential is ascribed, may allow some of the multiple steps to be bypassed in hepatocarcinogenesis. Therefore unlike for other cancers, HCV infection may be able to cause HCC in the absence of a complete set of genetic aberrations. Such a scenario, 'non-Vogelstein-type' carcinogenesis, would explain the rare feature of hepatocarcinogenesis in HCV infection, the extraordinarily high incidence and the multicentric nature of HCC development.
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Affiliation(s)
- Kazuhiko Koike
- Department of Infectious Diseases, Internal Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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Abstract
Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis and hepatocellular carcinoma (HCC). In man, the pathobiological changes associated with HCV infection have been attributed to both the immune system and direct viral cytopathic effects. Until now, the lack of simple culture systems to infect and propagate the virus has hampered progress in understanding the viral life cycle and pathogenesis of HCV infection, including the molecular mechanisms implicated in HCV-induced HCC. This clearly demonstrates the need to develop small animal models for the study of HCV-associated pathogenesis. This review describes and discusses the development of new HCV animal models to study viral infection and investigate the direct effects of viral protein expression on liver disease.
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Affiliation(s)
- Dina Kremsdorf
- INSERM U812, Universite Paris Descartes, CHU Necker, 156, rue de Vaugirard, Paris 75015, France.
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Abstract
Apoptosis signal-regulating kinase 1 (ASK1) is a mitogenactivated protein kinase (MAPK) kinase kinase that activates JNK and p38 kinases. ASK1 is activated by various stresses, such as reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, lipopolysaccharide (LPS) and calcium influx which are thought to be responsible for the pathogenesis or exacerbations of various human diseases. Recent studies revealed the involvement of ASK1 in ROS- or ER stressrelated diseases, suggesting that ASK1 may be a potential therapeutic target of various human diseases. In this review, we focus on the current findings for the relationship between pathogenesis and ASK1-MAPK pathways.
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Affiliation(s)
- Hiroaki Nagai
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan
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Paik MJ, Park KH, Park JJ, Kim KR, Ahn YH, Shin GT, Lee G. Patterns of Plasma Fatty Acids in Rat Models with Adenovirus Infection. BMB Rep 2007; 40:119-24. [PMID: 17244492 DOI: 10.5483/bmbrep.2007.40.1.119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Adenoviral vectors are among the most promising vectors available for human gene therapy. However, the use of recombinant adenoviral vectors, including replicationcompetent adenovirus (RCA), raises a variety of safety concerns in relation to the development of new therapies based on gene therapy. To examine how organic compounds change in rat plasma following the injection of adenovirus, beta-galactosidase expressing recombinant adenovirus (designated rAdLacZ) or RCA, we investigated the content of fatty acids (FAs), which are important biochemical indicators in pathological conditions. Pattern recognition analysis on the level of FAs in rat plasma is described for the visual discrimination of adenovirus infection groups from normal controls. Plasma FAs from four control rats (normal group), and from four rats with rAdLacZ infection and six rats with RCA infection (the two abnormal groups), were examined by gas chromatography-mass spectrometry in selected ion monitoring modes as their tert-butyldimethylsilyl derivatives. In total, 20 FAs were positively detected and quantified. The results of the Studentos t-test on the normal mean of two abnormal groups, the levels of three FAs (p< 0.05) from rAdLacZ group and eleven FAs (p < 0.05) from RCA group were significantly different. When star symbol plotting was applied to the group mean values of 20 FAs after normalization to the corresponding normal mean values, the resulting eicosagonal star patterns of the two infected groups were distorted into similar shapes, but were distinguishable from each other. Thus, these approaches will be useful for screening and monitoring of diagnostic markers for the effects of infection following the use of adenoviral vectors in gene therapy.
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Affiliation(s)
- Man Jeong Paik
- Biometabolite Analysis Laboratory, College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
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Naas T, Ghorbani M, Alvarez-Maya I, Lapner M, Kothary R, De Repentigny Y, Gomes S, Babiuk L, Giulivi A, Soare C, Azizi A, Diaz-Mitoma F. Characterization of liver histopathology in a transgenic mouse model expressing genotype 1a hepatitis C virus core and envelope proteins 1 and 2. J Gen Virol 2005; 86:2185-2196. [PMID: 16033966 DOI: 10.1099/vir.0.80969-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic hepatitis and hepatocellular carcinoma worldwide. The purpose of this study was to determine how the HCV structural proteins affect the dynamic structural and functional properties of hepatocytes and measure the extra-hepatic manifestations induced by these viral proteins. A transgenic mouse model was established by expressing core, E1 and E2 proteins downstream of a CMV promoter. HCV RNA was detected using RT-PCR in transgenic mouse model tissues, such as liver, kidney, spleen and heart. Expression of the transgene was analysed by real-time PCR to quantify viral RNA in different tissues at different ages. Immunofluorescence analysis revealed the expression of core, E1 and E2 proteins predominantly in hepatocytes. Lower levels of protein expression were detected in spleen and kidneys. HCV RNA and viral protein expression increased in the liver with age. Histological analysis of liver cells demonstrated steatosis in transgenic mice older than 3 months, which was more progressed with age. Electron microscopy analysis revealed alterations in nuclei, mitochondria and endoplasmic reticulum. HCV structural proteins induce a severe hepatopathy in the transgenic mouse model. These mice became more prone to liver and lymphoid tumour development and hepatocellular carcinoma. In this model, the extra-hepatic effects of HCV, which included swelling of renal tubular cells, were mild. It is likely that the HCV structural proteins mediate some of the histological alterations in hepatocytes by interfering with lipid transport and liver metabolism.
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Affiliation(s)
- Turaya Naas
- Department of Microbiology Immunology and Biochemistry, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Masoud Ghorbani
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Ikuri Alvarez-Maya
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Michael Lapner
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Rashmi Kothary
- Ottawa Health Research Institute, Molecular Medicine Program, Ottawa, ON, Canada, K1H 8L6
| | - Yves De Repentigny
- Ottawa Health Research Institute, Molecular Medicine Program, Ottawa, ON, Canada, K1H 8L6
| | - Susantha Gomes
- Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5B4
| | - Lorne Babiuk
- Department of Veterinary Microbiology, Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5E3
| | - Antonio Giulivi
- Division of Blood Borne Pathogens, Health Canada, Ottawa, ON, Canada, K1A 0L2
| | - Catalina Soare
- Department of Microbiology Immunology and Biochemistry, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Ali Azizi
- Department of Microbiology Immunology and Biochemistry, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
| | - Francisco Diaz-Mitoma
- Department of Microbiology Immunology and Biochemistry, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
- Division of Virology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON, Canada, K1H 8L1
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Chang TS, Lo SK, Shyr HY, Fang JT, Lee WC, Tai DI, Sheen IS, Lin DY, Chu CM, Liaw YF. Hepatitis C virus infection facilitates gallstone formation. J Gastroenterol Hepatol 2005; 20:1416-21. [PMID: 16105130 DOI: 10.1111/j.1440-1746.2005.03915.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Bile duct damage and hepatic steatosis are two characteristic histological findings in hepatitis C virus infection; and high prevalence of hepatitis C antibody is noted in patients with cholangiocarcinoma. The purpose of the present study was to examine the relationship between biliary diseases and hepatitis C virus infection. METHODS Persons who received a general checkup in Chang Gung Memorial Hospital between 2000 and 2002 were included. All of them had hemogram, serum biochemistry, hepatitis B surface antigen, hepatitis C antibody and ultrasonography studies. The prevalence of gallbladder stone, bile duct stone and gallbladder polyp/cholesterolosis were compared in different viral infection groups. RESULTS Of the 28 486 persons, 22 967 were negative for both hepatitis B surface antigen and hepatitis C antibody (group NBNC), 4152 were hepatitis B surface antigen carriers (broup B), 1195 were positive for hepatitis C antibody (group C), and 172 were positive for both markers. The 379 persons (1.3%) having had cholecystectomy were considered to have gallbladder stone at the time when cholecystectomy was done. Gallbladder stone was found in 6.0% persons of group NBNC, 5.4% in group B and 11.7% in group C. The prevalence of gallbladder stone in group C was found especially high for age groups 31-40 years and 61-70 years. The prevalence of bile duct stone was higher in group C (0.4%) than in group NBNC or B (both 0.1%). Stepwise logistic regression analysis showed that age, liver cirrhosis, body mass index, hepatitis C virus infection and gender were independent factors associated with gallbladder stone. CONCLUSIONS Hepatitis C virus infection facilitates gallstone formation.
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Affiliation(s)
- Te-Sheng Chang
- Liver Research Unit, Chang Gung Memorial Hospital, Taipei, Taiwan
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Yanagitani A, Yamada S, Yasui S, Shimomura T, Murai R, Murawaki Y, Hashiguchi K, Kanbe T, Saeki T, Ichiba M, Tanabe Y, Yoshida Y, Morino SI, Kurimasa A, Usuda N, Yamazaki H, Kunisada T, Ito H, Murawaki Y, Shiota G. Retinoic acid receptor alpha dominant negative form causes steatohepatitis and liver tumors in transgenic mice. Hepatology 2004; 40:366-75. [PMID: 15368441 DOI: 10.1002/hep.20335] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although attention has focused on the chemopreventive action of retinoic acid (RA) in hepatocarcinogenesis, the functional role of RA in the liver has yet to be clarified. To explore the role of RA in the liver, we developed transgenic mice expressing RA receptor (RAR) alpha- dominant negative form in hepatocytes using albumin promoter and enhancer. At 4 months of age, the RAR alpha- dominant negative form transgenic mice developed microvesicular steatosis and spotty focal necrosis. Mitochondrial beta-oxidation activity of fatty acids and expression of its related enzymes, including VLCAD, LCAD, and HCD, were down-regulated; on the other hand, peroxisomal beta-oxidation and its related enzymes, including AOX and BFE, were up-regulated. Expression of cytochrome p4504a10, cytochrome p4504a12, and cytochrome p4504a14 was increased, suggesting that omega-oxidation of fatty acids in microsomes was accelerated. In addition, formation of H2O2 and 8-hydroxy-2'-deoxyguanosine was increased. After 12 months of age, these mice developed hepatocellular carcinoma and adenoma of the liver. The incidence of tumor formation increased with age. Expression of beta-catenin and cyclin D1 was enhanced and the TCF-4/beta-catenin complex was increased, whereas the RAR alpha/ beta-catenin complex was decreased. Feeding on a high-RA diet reversed histological and biochemical abnormalities and inhibited the occurrence of liver tumors. These results suggest that hepatic loss of RA function leads to the development of steatohepatitis and liver tumors. In conclusion, RA plays an important role in preventing hepatocarcinogenesis in association with fatty acid metabolism and Wnt signaling.
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Affiliation(s)
- Atsushi Yanagitani
- Department of Genetic Medicine and Regenerative Therapeutics, Tottori University, Yonago, Japan
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Horie Y, Suzuki A, Kataoka E, Sasaki T, Hamada K, Sasaki J, Mizuno K, Hasegawa G, Kishimoto H, Iizuka M, Naito M, Enomoto K, Watanabe S, Mak TW, Nakano T. Hepatocyte-specific Pten deficiency results in steatohepatitis and hepatocellular carcinomas. J Clin Invest 2004. [PMID: 15199412 DOI: 10.1172/jci200420513] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PTEN is a tumor suppressor gene mutated in many human cancers, and its expression is reduced or absent in almost half of hepatoma patients. We used the Cre-loxP system to generate a hepatocyte-specific null mutation of Pten in mice (AlbCrePten(flox/flox) mice). AlbCrePten(flox/flox) mice showed massive hepatomegaly and steatohepatitis with triglyceride accumulation, a phenotype similar to human nonalcoholic steatohepatitis. Adipocyte-specific genes were induced in mutant hepatocytes, implying adipogenic-like transformation of these cells. Genes involved in lipogenesis and beta-oxidation were also induced, possibly as a result of elevated levels of the transactivating factors PPARgamma and SREBP1c. Importantly, the loss of Pten function in the liver led to tumorigenesis, with 47% of AlbCrePten(flox/flox) livers developing liver cell adenomas by 44 weeks of age. By 74-78 weeks of age, 100% of AlbCrePten(flox/flox) livers showed adenomas and 66% had hepatocellular carcinomas. AlbCrePten(flox/flox) mice also showed insulin hypersensitivity. In vitro, AlbCrePten(flox/flox) hepatocytes were hyperproliferative and showed increased hyperoxidation with abnormal activation of protein kinase B and MAPK. Pten is thus an important regulator of lipogenesis, glucose metabolism, hepatocyte homeostasis, and tumorigenesis in the liver.
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Affiliation(s)
- Yasuo Horie
- Department of Gastroenterology, Akita University School of Medicine, Akita, Japan
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Horie Y, Suzuki A, Kataoka E, Sasaki T, Hamada K, Sasaki J, Mizuno K, Hasegawa G, Kishimoto H, Iizuka M, Naito M, Enomoto K, Watanabe S, Mak TW, Nakano T. Hepatocyte-specific Pten deficiency results in steatohepatitis and hepatocellular carcinomas. J Clin Invest 2004; 113:1774-83. [PMID: 15199412 PMCID: PMC420505 DOI: 10.1172/jci20513] [Citation(s) in RCA: 504] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Accepted: 04/27/2004] [Indexed: 12/13/2022] Open
Abstract
PTEN is a tumor suppressor gene mutated in many human cancers, and its expression is reduced or absent in almost half of hepatoma patients. We used the Cre-loxP system to generate a hepatocyte-specific null mutation of Pten in mice (AlbCrePten(flox/flox) mice). AlbCrePten(flox/flox) mice showed massive hepatomegaly and steatohepatitis with triglyceride accumulation, a phenotype similar to human nonalcoholic steatohepatitis. Adipocyte-specific genes were induced in mutant hepatocytes, implying adipogenic-like transformation of these cells. Genes involved in lipogenesis and beta-oxidation were also induced, possibly as a result of elevated levels of the transactivating factors PPARgamma and SREBP1c. Importantly, the loss of Pten function in the liver led to tumorigenesis, with 47% of AlbCrePten(flox/flox) livers developing liver cell adenomas by 44 weeks of age. By 74-78 weeks of age, 100% of AlbCrePten(flox/flox) livers showed adenomas and 66% had hepatocellular carcinomas. AlbCrePten(flox/flox) mice also showed insulin hypersensitivity. In vitro, AlbCrePten(flox/flox) hepatocytes were hyperproliferative and showed increased hyperoxidation with abnormal activation of protein kinase B and MAPK. Pten is thus an important regulator of lipogenesis, glucose metabolism, hepatocyte homeostasis, and tumorigenesis in the liver.
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Affiliation(s)
- Yasuo Horie
- Department of Gastroenterology, Akita University School of Medicine, Akita, Japan
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