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Bunz M, Eisele M, Hu D, Ritter M, Kammerloher J, Lampl S, Schindler M. CD81 suppresses NF-κB signaling and is downregulated in hepatitis C virus expressing cells. Front Cell Infect Microbiol 2024; 14:1338606. [PMID: 38357447 PMCID: PMC10864554 DOI: 10.3389/fcimb.2024.1338606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/15/2024] [Indexed: 02/16/2024] Open
Abstract
The tetraspanin CD81 is one of the main entry receptors for Hepatitis C virus, which is a major causative agent to develop liver cirrhosis and hepatocellular carcinoma (HCC). Here, we identify CD81 as one of few surface proteins that are downregulated in HCV expressing hepatoma cells, discovering a functional role of CD81 beyond mediating HCV entry. CD81 was downregulated at the mRNA level in hepatoma cells that replicate HCV. Kinetics of HCV expression were increased in CD81-knockout cells and accompanied by enhanced cellular growth. Furthermore, loss of CD81 compensated for inhibition of pro-survival TBK1-signaling in HCV expressing cells. Analysis of functional phenotypes that could be associated with pro-survival signaling revealed that CD81 is a negative regulator of NF-κB. Interaction of the NF-κB subunits p50 and p65 was increased in cells lacking CD81. Similarly, we witnessed an overall increase in the total levels of phosphorylated and cellular p65 upon CD81-knockout in hepatoma cells. Finally, translocation of p65 in CD81-negative hepatoma cells was markedly induced upon stimulation with TNFα or PMA. Altogether, CD81 emerges as a regulator of pro-survival NF-κB signaling. Considering the important and established role of NF-κB for HCV replication and tumorigenesis, the downregulation of CD81 by HCV and the associated increase in NF-κB signaling might be relevant for viral persistence and chronic infection.
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Affiliation(s)
- Maximilian Bunz
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Mona Eisele
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Dan Hu
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Michael Ritter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Julia Kammerloher
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
| | - Sandra Lampl
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
| | - Michael Schindler
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
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2
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Cao D, Liu H. Dysregulated cholesterol regulatory genes in hepatocellular carcinoma. Eur J Med Res 2023; 28:580. [PMID: 38071335 PMCID: PMC10710719 DOI: 10.1186/s40001-023-01547-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Cholesterol is an indispensable component in mammalian cells, and cholesterol metabolism performs important roles in various biological activities. In addition to the Warburg effect, dysregulated cholesterol metabolism is one of the metabolic hallmarks of several cancers. It has reported that reprogrammed cholesterol metabolism facilitates carcinogenesis, metastasis, and drug-resistant in various tumors, including hepatocellular carcinoma (HCC). Some literatures have reported that increased cholesterol level leads to lipotoxicity, inflammation, and fibrosis, ultimately promoting the development and progression of HCC. Contrarily, other clinical investigations have demonstrated a link between higher cholesterol level and lower risk of HCC. These incongruent findings suggest that the connection between cholesterol and HCC is much complicated. In this report, we summarize the roles of key cholesterol regulatory genes including cholesterol biosynthesis, uptake, efflux, trafficking and esterification in HCC. In addition, we discuss promising related therapeutic targets for HCC.
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Affiliation(s)
- Dan Cao
- Department of Respiratory and Critical Care Medicine, Affiliated Hospital of North Sichuan Medical College, No. 1 the South of Maoyuan Road, Nanchong, 637000, Sichuan, People's Republic of China
| | - Huan Liu
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu, 610041, China.
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3
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Song YJ, Zhang J, Xu Z, Nie P, Chang MX. Liver X Receptor LXRα Promotes Grass Carp Reovirus Infection by Attenuating IRF3-CBP Interaction and Inhibiting RLR Antiviral Signaling. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1006-1019. [PMID: 37548504 DOI: 10.4049/jimmunol.2300214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 07/05/2023] [Indexed: 08/08/2023]
Abstract
Liver X receptors (LXRs) are nuclear receptors involved in metabolism and the immune response. Different from mammalian LXRs, which include two isoforms, LXRα and LXRβ, only a single LXRα gene exists in the piscine genomes. Although a study has suggested that piscine LXR inhibits intracellular bacterial survival, the functions of piscine LXRα in viral infection are unknown. In this study, we show that overexpression of LXRα from grass carp (Ctenopharyngodon idellus), which is named as gcLXRα, increases host susceptibility to grass carp reovirus (GCRV) infection, whereas gcLXRα knockdown in CIK (C. idellus kidney) cells inhibits GCRV infection. Consistent with these functional studies, gcLXRα knockdown promotes the transcription of antiviral genes involved in the RIG-I-like receptor (RLR) antiviral signaling pathway, including IFN regulatory factor (IRF3) and the type I IFN IFN1. Further results show that gcLXRα knockdown induces the expression of CREB-binding protein (CBP), a transcriptional coactivator. In the knockdown of CBP, the inhibitory effect of gcLXRα knockdown in limiting GCRV infection is completely abolished. gcLXRα also interacts with IRF3 and CBP, which impairs the formation of the IRF3/CBP transcription complex. Moreover, gcLXRα heterodimerizes with RXRg, which cooperatively impair the transcription of the RLR antiviral signaling pathway and promote GCRV infection. Taken together, to our knowledge, our findings provide new insight into the functional correlation between nuclear receptor LXRα and the RLR antiviral signaling pathway, and they demonstrate that gcLXRα can impair the RLR antiviral signaling pathway and the production of type I IFN via forming gcLXRα/RXRg complexes and attenuating IRF3/CBP complexes.
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Affiliation(s)
- Yun Jie Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jie Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhen Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Pin Nie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Ming Xian Chang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
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4
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Han N, Yuan M, Yan L, Tang H. Emerging Insights into Liver X Receptor α in the Tumorigenesis and Therapeutics of Human Cancers. Biomolecules 2023; 13:1184. [PMID: 37627249 PMCID: PMC10452869 DOI: 10.3390/biom13081184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Liver X receptor α (LXRα), a member of the nuclear receptor superfamily, is identified as a protein activated by ligands that interacts with the promoters of specific genes. It regulates cholesterol, bile acid, and lipid metabolism in normal physiological processes, and it participates in the development of some related diseases. However, many studies have demonstrated that LXRα is also involved in regulating numerous human malignancies. Aberrant LXRα expression is emerging as a fundamental and pivotal factor in cancer cell proliferation, invasion, apoptosis, and metastasis. Herein, we outline the expression levels of LXRα between tumor tissues and normal tissues via the Oncomine and Tumor Immune Estimation Resource (TIMER) 2.0 databases; summarize emerging insights into the roles of LXRα in the development, progression, and treatment of different human cancers and their diversified mechanisms; and highlight that LXRα can be a biomarker and therapeutic target in diverse cancers.
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Affiliation(s)
- Ning Han
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
| | - Man Yuan
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Libo Yan
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
| | - Hong Tang
- Center of Infectious Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, China
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5
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Gong Z, Yan Z, Liu W, Luo B. Oncogenic viruses and host lipid metabolism: a new perspective. J Gen Virol 2023; 104. [PMID: 37279154 DOI: 10.1099/jgv.0.001861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
As noncellular organisms, viruses do not have their own metabolism and rely on the metabolism of host cells to provide energy and metabolic substances for their life cycles. Increasing evidence suggests that host cells infected with oncogenic viruses have dramatically altered metabolic requirements and that oncogenic viruses produce substances used for viral replication and virion production by altering host cell metabolism. We focused on the processes by which oncogenic viruses manipulate host lipid metabolism and the lipid metabolism disorders that occur in oncogenic virus-associated diseases. A deeper understanding of viral infections that cause changes in host lipid metabolism could help with the development of new antiviral agents as well as potential new therapeutic targets.
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Affiliation(s)
- Zhiyuan Gong
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, PR China
| | - Zhiyong Yan
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, PR China
| | - Wen Liu
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, PR China
| | - Bing Luo
- Department of Pathogenic Biology, School of Basic Medicine, Qingdao University, Qingdao 266071, PR China
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6
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Dias SSG, Cunha-Fernandes T, Souza-Moreira L, Soares VC, Lima GB, Azevedo-Quintanilha IG, Santos J, Pereira-Dutra F, Freitas C, Reis PA, Rehen SK, Bozza FA, Souza TML, de Almeida CJG, Bozza PT. Metabolic reprogramming and lipid droplets are involved in Zika virus replication in neural cells. J Neuroinflammation 2023; 20:61. [PMID: 36882750 PMCID: PMC9992922 DOI: 10.1186/s12974-023-02736-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/16/2023] [Indexed: 03/09/2023] Open
Abstract
Zika virus (ZIKV) infection is a global public health concern linked to adult neurological disorders and congenital diseases in newborns. Host lipid metabolism, including lipid droplet (LD) biogenesis, has been associated with viral replication and pathogenesis of different viruses. However, the mechanisms of LD formation and their roles in ZIKV infection in neural cells are still unclear. Here, we demonstrate that ZIKV regulates the expression of pathways associated with lipid metabolism, including the upregulation and activation of lipogenesis-associated transcription factors and decreased expression of lipolysis-associated proteins, leading to significant LD accumulation in human neuroblastoma SH-SY5Y cells and in neural stem cells (NSCs). Pharmacological inhibition of DGAT-1 decreased LD accumulation and ZIKV replication in vitro in human cells and in an in vivo mouse model of infection. In accordance with the role of LDs in the regulation of inflammation and innate immunity, we show that blocking LD formation has major roles in inflammatory cytokine production in the brain. Moreover, we observed that inhibition of DGAT-1 inhibited the weight loss and mortality induced by ZIKV infection in vivo. Our results reveal that LD biogenesis triggered by ZIKV infection is a crucial step for ZIKV replication and pathogenesis in neural cells. Therefore, targeting lipid metabolism and LD biogenesis may represent potential strategies for anti-ZIKV treatment development.
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Affiliation(s)
- Suelen Silva Gomes Dias
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Tamires Cunha-Fernandes
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Luciana Souza-Moreira
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Vinicius Cardoso Soares
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.,Programa de Imunologia e Inflamação, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Giselle Barbosa Lima
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | | | - Julia Santos
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Filipe Pereira-Dutra
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Caroline Freitas
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Patricia A Reis
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.,Departamento de Bioquímica, Instituto de Biologia Roberto Alcântara Gomes, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Stevens Kastrup Rehen
- Instituto D'Or de Pesquisa e Ensino (IDOR), Rio de Janeiro, Brazil.,Instituto de Biologia, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernando A Bozza
- Instituto D'Or de Pesquisa e Ensino (IDOR), Rio de Janeiro, Brazil.,Instituto Nacional de Infectologia Evandro Chagas (INI), FIOCRUZ, Rio de Janeiro, Brazil
| | - Thiago M Lopes Souza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Inovação em Doenças de Populações Negligenciadas (INCT/IDPN), Centro de Desenvolvimento Tecnológico em Saúde, (CDTS), FIOCRUZ, Rio de Janeiro, Brazil
| | - Cecilia J G de Almeida
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| | - Patricia T Bozza
- Laboratório de Imunofarmacologia, Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil.
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7
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Ohashi H, Nishioka K, Kurihara T, Nakamura K, Yamasaki M, Ibayashi Y, Fuchiyama K, Kamo S, Furuyama Y, Ohgane K, Okada M, Kamisuki S, Watashi K, Kuramochi K. Anti-hepatitis C Virus Activity of Juglorubin Derivatives. Chem Pharm Bull (Tokyo) 2023; 71:843-845. [PMID: 37914261 DOI: 10.1248/cpb.c23-00489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Juglorubin is a natural dye isolated from the culture of Streptomyces sp. 3094, 815, and GW4184. It has been previously synthesized via the biomimetic dimerization of juglomycin C, a plausible genetic precursor. In this study, the derivatives of juglorubin, 1-O-acetyljuglorubin dimethyl ester and juglorubin dimethyl ester, were found to exhibit antiviral activity against hepatitis C virus (HCV) without exerting any remarkable cytotoxicity against host Huh-7 cells. They also inhibited liver X receptor α activation and lipid droplet accumulation in Huh-7 cells. These findings suggest that 1-O-acetyljuglorubin dimethyl ester and juglorubin dimethyl ester targeted the host factors required for HCV production.
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Affiliation(s)
- Hirofumi Ohashi
- Department of Applied Biological Science, Tokyo University of Science
- Department of Virology II, National Institute of Infectious Diseases
- Research Center for Drug and Vaccine Development, National Institute of Infectious Diseases
| | - Kazane Nishioka
- Department of Applied Biological Science, Tokyo University of Science
- Department of Virology II, National Institute of Infectious Diseases
| | - Tomoki Kurihara
- Department of Applied Biological Science, Tokyo University of Science
- Department of Virology II, National Institute of Infectious Diseases
- Research Center for Drug and Vaccine Development, National Institute of Infectious Diseases
| | | | - Masako Yamasaki
- Department of Applied Biological Science, Tokyo University of Science
- Department of Virology II, National Institute of Infectious Diseases
- Research Center for Drug and Vaccine Development, National Institute of Infectious Diseases
| | - Yuuka Ibayashi
- Department of Applied Biological Science, Tokyo University of Science
| | - Kanta Fuchiyama
- Department of Applied Biological Science, Tokyo University of Science
| | - Shogo Kamo
- Department of Applied Biological Science, Tokyo University of Science
- Department of Synthetic Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University
| | - Yuuki Furuyama
- Department of Applied Biological Science, Tokyo University of Science
| | - Kenji Ohgane
- Department of Applied Biological Science, Tokyo University of Science
- Department of Chemistry, Ochanomizu University
| | - Maiko Okada
- School of Bioscience and Biotechnology, Tokyo University of Technology
| | - Shinji Kamisuki
- School of Veterinary Medicine, Azabu University
- Center for Human and Animal Symbiosis Science, Azabu University
| | - Koichi Watashi
- Department of Applied Biological Science, Tokyo University of Science
- Department of Virology II, National Institute of Infectious Diseases
- Research Center for Drug and Vaccine Development, National Institute of Infectious Diseases
| | - Kouji Kuramochi
- Department of Applied Biological Science, Tokyo University of Science
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8
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Differential Expression of the Host Lipid Regulators ANGPTL-3 and ANGPTL-4 in HCV Infection and Treatment. Int J Mol Sci 2021; 22:ijms22157961. [PMID: 34360721 PMCID: PMC8348577 DOI: 10.3390/ijms22157961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 11/29/2022] Open
Abstract
Host lipid metabolism reprogramming is essential for hepatitis C virus (HCV) infection and progression to severe liver disease. Direct-acting antivirals (DAAs) achieve a sustained virological response (SVR) in most patients, but virus eradication does not always protect against hepatocellular carcinoma (HCC). Angiopoietin-like protein-3 (ANGPTL-3) and angiopoietin-like protein-4 (ANGPTL-4) regulate the clearance of plasma lipids by inhibiting cellular lipase activity and possess emerging roles in tumourigenesis. We used ELISA and RT-qPCR to investigate ANGPTL-3 and ANGPTL-4 expression in HCV patients with characterised fibrosis throughout the natural history of hepatitis C and in long-term HCV infection in vitro, before and after DAA treatment. ANGPTL-3 was decreased in patients with advanced fibrosis compared to other disease stages, while ANGPTL-4 was progressively increased from acute infection to cirrhosis and HCC, peaking at the advanced fibrosis stage. Only ANGPTL-3 mRNA was down-regulated during early infection in vitro, although both ANGPTLs were increased later. DAA treatment did not alter ANGPTL-3 levels in advanced fibrosis/cirrhosis and in HCV infection in vitro, in contrast to ANGPTL-4. The association between ANGPTLs and fibrosis in HCV infection was underlined by an inverse correlation between the levels of ANGPTLs and serum transforming growth factor- β (TGF-β). Collectively, we demonstrate the pivotal role of advanced fibrosis in defining the expression fate of ANGPTLs in HCV infection and after treatment and propose a role for ANGPTL-3 as a contributor to post-treatment deregulation of lipid metabolism that could predispose certain individuals to HCC development.
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9
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Fowl Adenovirus Serotype 4 Induces Hepatic Steatosis via Activation of Liver X Receptor-α. J Virol 2021; 95:JVI.01938-20. [PMID: 33361420 DOI: 10.1128/jvi.01938-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022] Open
Abstract
Fowl adenovirus serotype 4 (FAdV-4) is a hepatotropic virus that causes severe hepatic damage characterized by basophilic intranuclear inclusion bodies, vacuolar degeneration, and multifocal necrosis in hepatocytes. Many aspects of FAdV-4 infection and pathogenesis, however, remain unknown. Here, we found that FAdV-4-induced hepatic injury is accompanied by the accumulation of oil droplets (triglycerides) in the cytoplasm of hepatocytes, a typical indicator of steatosis, in FAdV-4-infected chickens. Significant upregulation of adipose synthesis-related genes, such as liver X receptor-α (LXR-α), peroxisome proliferator-activated receptor gamma (PPAR-γ), and sterol regulatory element-binding protein-1c (SREBP-1c), and significant downregulation of low-density lipoprotein secretion-related genes and lipid oxidation- and lipid decomposition-related genes were observed in the infected chickens. FAdV-4 infection in cultured leghorn male hepatoma (LMH) cells caused similar signs of steatosis, with alterations in various lipogenesis-related genes. We eliminated the effect of LXR-α activation on FAdV-4-induced steatosis and found that treatment with an LXR-α antagonist (SR9243) and RNA interference (small interfering RNA targeting LXR-α [Si-LXR-α]) decreased the number of oil droplets and the accumulation of lipogenic genes, but treatment with an LXR-α agonist (T0901317) increased the number of oil droplets and the accumulation of lipogenic genes in the cells. Additionally, SR9243 treatment or Si-LXR-α transfection led to significant reductions in viral DNA level, protein expression, and virus production, whereas T0901317 treatment caused significant increases in viral DNA level, protein expression, and virus production. However, inhibition of SREBP-1c activity had no significant effect on virus production. Collectively, these results indicated that FAdV-4-induced steatosis involves activation of the LXR-α signaling pathway, which might be a molecular mechanism underlying the hepatic injury associated with FAdV-4 infection.IMPORTANCE Fowl adenovirus serotype 4 (FAdV-4) is an important hepatotropic adenovirus in chicken, but the underlying mechanism of FAdV-4-induced hepatic injury remains unclear. We report here that infection with FAdV-4 induced the accumulation of oil droplets (triglycerides) in the cytoplasm of hepatocytes, a typical indicator of steatosis, in the livers of chickens. FAdV-4-induced steatosis might be caused by a disrupted balance of fat metabolism, as evidenced by differential regulation of various lipase genes. The significant upregulation of liver X receptor-α (LXR-α) prompted us to investigate the interplay between LXR-α activation and FAdV-4-induced steatosis. Treatment with an agonist, an antagonist, or RNA interference targeting LXR-α in cultured leghorn male hepatoma (LMH) cells indicated that FAdV-4-induced steatosis was dependent upon LXR-α activation, which contributed to virus replication. These results provide important mechanistic insights, revealing that FAdV-4 induces hepatic steatosis by activating the LXR-α signaling pathway and highlighting the therapeutic potential of strategies targeting the LXR-α pathway for the treatment of FAdV-4 infection.
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10
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Dimitriadis A, Foka P, Kyratzopoulou E, Karamichali E, Petroulia S, Tsitoura P, Kakkanas A, Eliadis P, Georgopoulou U, Mamalaki A. The Hepatitis C virus NS5A and core proteins exert antagonistic effects on HAMP gene expression: the hidden interplay with the MTF-1/MRE pathway. FEBS Open Bio 2021; 11:237-250. [PMID: 33247551 PMCID: PMC7780115 DOI: 10.1002/2211-5463.13048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/26/2022] Open
Abstract
Hepcidin, a 25-amino acid peptide encoded by the HAMP gene and produced mainly by hepatocytes and macrophages, is a mediator of innate immunity and the central iron-regulatory hormone. Circulating hepcidin controls iron efflux by inducing degradation of the cellular iron exporter ferroportin. HCV infection is associated with hepatic iron overload and elevated serum iron, which correlate with poor antiviral responses. The HCV nonstructural NS5A protein is known to function in multiple aspects of the HCV life cycle, probably exerting its activity in concert with cellular factor(s). In this study, we attempted to delineate the effect of HCV NS5A on HAMP gene expression. We observed that transient transfection of hepatoma cell lines with HCV NS5A resulted in down-regulation of HAMP promoter activity. A similar effect was evident after transduction of Huh7 cells with a recombinant baculovirus vector expressing NS5A protein. We proceeded to construct an NS5A-expressing stable cell line, which also exhibited down-regulation of HAMP gene promoter activity and significant reduction of HAMP mRNA and hepcidin protein levels. Concurrent expression of HCV core protein, a well-characterized hepcidin inducer, revealed antagonism between those two proteins for hepcidin regulation. In attempting to identify the pathways involved in NS5A-driven reduction of hepcidin levels, we ruled out any NS5A-induced alterations in the expression of the well-known hepcidin inducers SMAD4 and STAT3. Further analysis linked the abundance of intracellular zinc ions and the deregulation of the MTF-1/MRE/hepcidin axis with the observed phenomenon. This effect could be associated with distinct phases in HCV life cycle.
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Affiliation(s)
- Alexios Dimitriadis
- Laboratory of Molecular Biology and ImmunobiotechnologyHellenic Pasteur InstituteAthensGreece
| | - Pelagia Foka
- Laboratory of Molecular VirologyHellenic Pasteur InstituteAthensGreece
| | - Eleni Kyratzopoulou
- Laboratory of Molecular Biology and ImmunobiotechnologyHellenic Pasteur InstituteAthensGreece
| | | | | | - Panagiota Tsitoura
- Laboratory of Molecular VirologyHellenic Pasteur InstituteAthensGreece
- Present address:
Laboratory of Molecular Biology and ImmunobiotechnologyHellenic Pasteur InstituteAthensGreece
| | | | - Petros Eliadis
- Laboratory of Molecular Biology and ImmunobiotechnologyHellenic Pasteur InstituteAthensGreece
| | | | - Avgi Mamalaki
- Laboratory of Molecular Biology and ImmunobiotechnologyHellenic Pasteur InstituteAthensGreece
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11
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Consumption of salt leads to ameliorate symptoms of metabolic disorder and change of gut microbiota. Eur J Nutr 2020; 59:3779-3790. [DOI: 10.1007/s00394-020-02209-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 02/14/2020] [Indexed: 12/17/2022]
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12
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Meng Z, Liu Q, Sun F, Qiao L. Hepatitis C virus nonstructural protein 5A perturbs lipid metabolism by modulating AMPK/SREBP-1c signaling. Lipids Health Dis 2019; 18:191. [PMID: 31684957 PMCID: PMC6829953 DOI: 10.1186/s12944-019-1136-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/20/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Steatosis is an important clinical manifestation associated with chronic hepatitis C virus (HCV) infection. AMP-activated protein kinase (AMPK), a major mediator of lipid metabolism, regulates HCV-associated hepatic steatosis, but the underlying mechanisms remain obscure. Here we investigated the mechanism of HCV nonstructural protein 5A (NS5A)-induced lipid accumulation by the AMPK/SREBP-1c pathway. METHODS We generated model mice by injecting recombinant lentiviral particles expressing the NS5A protein (genotype 3a) via the tail vein. The serum levels of alanine aminotransferase (ALT), free fatty acids (FFAs) and triglycerides (TG) were examined. H&E and Oil Red O staining were used to examine lipid droplets. Immunohistochemistry staining, quantitative real-time PCR and Western blotting were used to determine the expression of lipogenic genes. RESULTS Our results showed that the serum levels of ALT, FFAs and TG, as well as the accumulation of hepatic lipid droplets, were increased significantly in mice infected with NS5A-expressing lentiviral particles. NS5A inhibited AMPK phosphorylation and increased the expression levels of sterol regulatory element binding protein-1c (SREBP-1c), acetyl-coenzyme A carboxylase 1 (ACC1) and fatty acid synthase (FASN) in vivo and in vitro. Further investigation revealed that pharmacological activation or ectopic expression of AMPK neutralized the upregulation of SREBP-1c, ACC1 and FASN, and ameliorated hepatic lipid accumulation induced by NS5A. Ectopic expression of SREBP-1c enhanced NS5A-induced hepatic lipid accumulation, which was dramatically reversed by pharmacological activation of AMPK. CONCLUSIONS Collectively, we demonstrate that NS5A induces hepatic lipid accumulation via the AMPK/SREBP-1c pathway.
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Affiliation(s)
- Ziyu Meng
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin, 300134, China
| | - Qiang Liu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), School of Public Health Vaccinology and Immunotherapeutics, Department of Veterinary Microbiology, University of Saskatchewan, S7N5E3, Saskatoon, Canada
| | - Fujun Sun
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin, 300134, China
| | - Ling Qiao
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Tianjin Medical University Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin, 300134, China.
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13
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Baiocchini A, Del Nonno F, Taibi C, Visco-Comandini U, D'Offizi G, Piacentini M, Falasca L. Liver sinusoidal endothelial cells (LSECs) modifications in patients with chronic hepatitis C. Sci Rep 2019; 9:8760. [PMID: 31217430 PMCID: PMC6584733 DOI: 10.1038/s41598-019-45114-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 05/24/2019] [Indexed: 02/07/2023] Open
Abstract
The sinusoidal endothelial cells present in the liver (LSECs) are tipically characterized by the presence of pores (fenestrae). During some pathological conditions LSECs undergo "capillarization", a process characterized by loss of fenestrations and acquisition of a vascular phenotype. In chronic liver disease capillarization has been reported to precede the development of fibrosis. LSECs modification in the setting of HCV infection is currently poorly investigated. Considering that HCV accounts for important changes in hepatocytes and in view of the intimate connection between hepatocytes and LSECs, here we set out to study in great detail the LSECs modifications in individuals with HCV-dependent chronic hepatitis. Electron microscopy analysis, and evaluation of CD32, CD31 and caveolin-1 expression showed that in HCV infection LSECs display major morphological changes but maintain their phenotypical identity. Capillarization was observed only in cases at initial stages of fibrosis. Our findings showed that the severity of LSECs modifications appears to be correlated with hepatocytes damage and fibrosis stage providing novel insight in the pathogenesis of HCV-chronic hepatitis.
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Affiliation(s)
- Andrea Baiocchini
- Pathology Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Franca Del Nonno
- Pathology Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Chiara Taibi
- Infectious Disease-Hepatology Unit, POIT Department, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Ubaldo Visco-Comandini
- Infectious Disease-Hepatology Unit, POIT Department, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Gianpiero D'Offizi
- Infectious Disease-Hepatology Unit, POIT Department, National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Mauro Piacentini
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
- Laboratory of Electron Microscopy, Department of Epidemiology and Preclinical Research National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy
| | - Laura Falasca
- Laboratory of Electron Microscopy, Department of Epidemiology and Preclinical Research National Institute for Infectious Diseases Lazzaro Spallanzani-IRCCS, Rome, Italy.
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14
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Bang BR, Li M, Tsai KN, Aoyagi H, Lee SA, Machida K, Aizaki H, Jung JU, Ou JHJ, Saito T. Regulation of Hepatitis C Virus Infection by Cellular Retinoic Acid Binding Proteins through the Modulation of Lipid Droplet Abundance. J Virol 2019; 93:e02302-18. [PMID: 30728260 PMCID: PMC6450116 DOI: 10.1128/jvi.02302-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/31/2019] [Indexed: 02/08/2023] Open
Abstract
Retinoid (vitamin A) is an essential diet constituent that governs a broad range of biological processes. Its biologically active metabolite, all-trans retinoic acid (ATRA), exhibits a potent antiviral property by enhancing both innate and adaptive antiviral immunity against a variety of viral pathogens, such as, but not limited to, HIV, respiratory syncytial virus (RSV), herpes simplex virus (HSV), and measles. Even though the hepatocyte is highly enriched with retinoid and its metabolite ATRA, it supports the establishment of efficient hepatitis C virus (HCV) replication. Here, we demonstrate the hepatocyte-specific cell-intrinsic mechanism by which ATRA exerts either a proviral or antiviral effect, depending on how it engages cellular retinoic acid binding proteins (CRABPs). We found that the engagement of CRABP1 by ATRA potently supported viral infection by promoting the accumulation of lipid droplets (LDs), which robustly enhanced the formation of a replication complex on the LD-associated endoplasmic reticulum (ER) membrane. In contrast, ATRA binding to CRABP2 potently inhibited HCV via suppression of LD accumulation. However, this antiviral effect of CRABP2 was abrogated due to the functional and quantitative predominance of CRABP1 in the hepatocytes. In summary, our study demonstrates that CRABPs serve as an on-off switch that modulates the efficiency of the HCV life cycle and elucidates how HCV evades the antiviral properties of ATRA via the exploitation of CRABP1 functionality.IMPORTANCE ATRA, a biologically active metabolite of vitamin A, exerts pleiotropic biological effects, including the activation of both innate and adaptive immunity, thereby serving as a potent antimicrobial compound against numerous viral pathogens. Despite the enrichment of hepatocytes with vitamin A, HCV still establishes an efficient viral life cycle. Here, we discovered that the hepatocellular response to ATRA creates either a proviral or an antiviral environment depending on its engagement with CRABP1 or -2, respectively. CRABP1 supports the robust replication of HCV, while CRABP2 potently inhibits the efficiency of viral replication. Our biochemical, genetic, and microscopic analyses reveal that the pro- and antiviral effects of CRABPs are mediated by modulation of LD abundance, where HCV establishes the platform for viral replication and assembly on the LD-associated ER membrane. This study uncovered a cell-intrinsic mechanism by which HCV exploits the proviral function of CRABP1 to establish an efficient viral life cycle.
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Affiliation(s)
- Bo-Ram Bang
- Department of Medicine, Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Meng Li
- Bioinformatics Service, Norris Medical Library, University of Southern California, Los Angeles, California, USA
| | - Kuen-Nan Tsai
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Haruyo Aoyagi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shin-Ae Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Keigo Machida
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Hideki Aizaki
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jing-Hsiung James Ou
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Takeshi Saito
- Department of Medicine, Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- USC Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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15
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Wan XP, Xie P, Bu Z, Zou XT, Gong DQ. Prolactin induces lipid synthesis of organ-cultured pigeon crops. Poult Sci 2019; 98:1842-1853. [PMID: 30590797 DOI: 10.3382/ps/pey540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 12/01/2018] [Indexed: 12/29/2022] Open
Abstract
The objective of this research was to examine the effects of prolactin (PRL) on the lipid synthesis of organ-cultured pigeon crops in vitro. In experiment 1, the histology, activities of enzymes, and expression of genes involved in metabolism and apoptosis of organ-cultured pigeon crops were analyzed over a 7-d culture period. The results showed that cultured crops maintained their structural integrity for up to 3 d in vitro. Beyond 3 d, caspase-3 activity and Bak1 gene expression increased with day of culture, whereas the activities of succinate dehydrogenase, Na+-K+-ATPase, Ca2+-Mg2+-ATPase, total ATPase, and gene expression of Bcl-2 and CK-19 diminished (P < 0.05). In experiment 2, the crops were cultured for 24, 36, and 48 h in medium containing 0, 25, or 50 ng/mL PRL, respectively, and the accumulation of lipid droplets, lipid content, and expression of fatty acid transportation- and lipogenesis-related genes were analyzed. The results showed that the crops with PRL supplements showed higher amounts of lipid droplets than those of the controls, and the droplets were mainly located in the basal nutritive layer in response to PRL. The efficacy of inducing lipid accumulation increased as the concentration of PRL increased. Crops with 50 ng/mL PRL incubated for 36 h displayed the maximal lipid content. Increasing the concentration of PRL from 0 to 50 ng/mL resulted in a dose-dependent increase in the expression of acetyl-CoA carboxylase, fatty acid synthase, fatty acid translocase, fatty acid binding protein 5, acyl-CoA binding protein, and peroxisome proliferator-activated receptor γ genes after incubation for 36 h (P < 0.05). Therefore, our results indicated that the organ-cultured pigeon crops maintained good viability for up to 3 d in vitro. Furthermore, PRL induced the lipid synthesis of organ-cultured pigeon crops in a dose- and time-dependent manner, which was related to the increased expression of genes involved in fatty acid transportation and lipogenesis.
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Affiliation(s)
- X P Wan
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China.,Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Science, Zhejiang University, Hangzhou 310058, China
| | - P Xie
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China.,College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Z Bu
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, China
| | - X T Zou
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Science, Zhejiang University, Hangzhou 310058, China
| | - D Q Gong
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
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16
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Goher SS, Griffett K, Hegazy L, Elagawany M, Arief MM, Avdagic A, Banerjee S, Burris TP, Elgendy B. Development of novel liver X receptor modulators based on a 1,2,4-triazole scaffold. Bioorg Med Chem Lett 2019; 29:449-453. [DOI: 10.1016/j.bmcl.2018.12.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/30/2018] [Accepted: 12/12/2018] [Indexed: 02/02/2023]
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17
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Zhang C, Hu J, Sheng L, Yuan M, Wu Y, Chen L, Wang G, Qiu Z. Ellagic acid ameliorates AKT-driven hepatic steatosis in mice by suppressing de novo lipogenesis via the AKT/SREBP-1/FASN pathway. Food Funct 2019; 10:3410-3420. [DOI: 10.1039/c9fo00284g] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ellagic acid alleviates hepatic lipid accumulation in mice by suppressing AKT-driven de novo lipogenesis.
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Affiliation(s)
- Cong Zhang
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Junjie Hu
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Lei Sheng
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Ming Yuan
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Yong Wu
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Liang Chen
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
| | - Guihong Wang
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
- Key Laboratory of Chinese Medicine Resource and Compound Prescription
| | - Zhenpeng Qiu
- College of Pharmacy
- Hubei University of Chinese Medicine
- Wuhan
- People's Republic of China
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18
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Singaravelu R, Quan C, Powdrill MH, Shaw TA, Srinivasan P, Lyn RK, Alonzi RC, Jones DM, Filip R, Russell RS, Pezacki JP. MicroRNA-7 mediates cross-talk between metabolic signaling pathways in the liver. Sci Rep 2018; 8:361. [PMID: 29321595 PMCID: PMC5762714 DOI: 10.1038/s41598-017-18529-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 12/08/2017] [Indexed: 12/26/2022] Open
Abstract
MicroRNAs (miRNAs) have emerged as critical regulators of cellular metabolism. To characterise miRNAs crucial to the maintenance of hepatic lipid homeostasis, we examined the overlap between the miRNA signature associated with inhibition of peroxisome proliferator activated receptor-α (PPAR-α) signaling, a pathway regulating fatty acid metabolism, and the miRNA profile associated with 25-hydroxycholesterol treatment, an oxysterol regulator of sterol regulatory element binding protein (SREBP) and liver X receptor (LXR) signaling. Using this strategy, we identified microRNA-7 (miR-7) as a PPAR-α regulated miRNA, which activates SREBP signaling and promotes hepatocellular lipid accumulation. This is mediated, in part, by suppression of the negative regulator of SREBP signaling: ERLIN2. miR-7 also regulates genes associated with PPAR signaling and sterol metabolism, including liver X receptor β (LXR-β), a transcriptional regulator of sterol synthesis, efflux, and excretion. Collectively, our findings highlight miR-7 as a novel mediator of cross-talk between PPAR, SREBP, and LXR signaling pathways in the liver.
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Affiliation(s)
- Ragunath Singaravelu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Curtis Quan
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Megan H Powdrill
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Tyler A Shaw
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Prashanth Srinivasan
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Rodney K Lyn
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Rhea C Alonzi
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Daniel M Jones
- Immunology and Infectious Diseases, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3V6, Canada
| | - Roxana Filip
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Rodney S Russell
- Immunology and Infectious Diseases, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3V6, Canada
| | - John P Pezacki
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
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19
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Recent Advances in the Pathogenesis of Hepatitis C Virus-Related Non-Alcoholic Fatty Liver Disease and Its Impact on Patients Cured of Hepatitis C. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s11901-017-0370-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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20
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Kim JH, Sung PS, Lee EB, Hur W, Park DJ, Shin EC, Windisch MP, Yoon SK. GRIM-19 Restricts HCV Replication by Attenuating Intracellular Lipid Accumulation. Front Microbiol 2017; 8:576. [PMID: 28443075 PMCID: PMC5387058 DOI: 10.3389/fmicb.2017.00576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/20/2017] [Indexed: 12/15/2022] Open
Abstract
Gene-associated with retinoid-interferon-induced mortality 19 (GRIM-19) targets multiple signaling pathways involved in cell death and growth. However, the role of GRIM-19 in the pathogenesis of hepatitis virus infections remains unexplored. Here, we investigated the restrictive effects of GRIM-19 on the replication of hepatitis C virus (HCV). We found that GRIM-19 protein levels were reduced in HCV-infected Huh7 cells and Huh7 cells harboring HCV replicons. Moreover, ectopically expressed GRIM-19 caused a reduction in both intracellular viral RNA levels and secreted viruses in HCVcc-infected cell cultures. The restrictive effect on HCV replication was restored by treatment with siRNA against GRIM-19. Interestingly, GRIM-19 overexpression did not alter the level of phosphorylated STAT3 or its subcellular distribution. Strikingly, forced expression of GRIM-19 attenuated an increase in intracellular lipid droplets after oleic acid (OA) treatment or HCVcc infection. GRIM-19 overexpression abrogated fatty acid-induced upregulation of sterol regulatory element-binding transcription factor-1 (SREBP-1c), resulting in attenuated expression of its target genes such as fatty acid synthase (FAS) and acetyl CoA carboxylase (ACC). Treatment with OA or overexpression of SREBP-1c in GRIM-19-expressing, HCVcc-infected cells restored HCV replication. Our results suggest that GRIM-19 interferes with HCV replication by attenuating intracellular lipid accumulation and therefore is an anti-viral host factor that could be a promising target for HCV treatment.
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Affiliation(s)
- Jung-Hee Kim
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Pil S Sung
- Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Eun B Lee
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Wonhee Hur
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Dong J Park
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
| | - Eui-Cheol Shin
- Laboratory of Immunology and Infectious Diseases, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea
| | - Marc P Windisch
- Hepatitis Research Laboratory, Discovery Biology Department, Institut Pasteur Korea, Seongnam-siGyeonggi-do, South Korea
| | - Seung K Yoon
- The Catholic University Liver Research Center and WHO Collaborating Center of Viral Hepatitis, The Catholic University of KoreaSeoul, South Korea
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21
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Rudraiah S, Zhang X, Wang L. Nuclear Receptors as Therapeutic Targets in Liver Disease: Are We There Yet? Annu Rev Pharmacol Toxicol 2016; 56:605-626. [PMID: 26738480 DOI: 10.1146/annurev-pharmtox-010715-103209] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nuclear receptors (NR) are ligand-modulated transcription factors that play diverse roles in cell differentiation, development, proliferation, and metabolism and are associated with numerous liver pathologies such as cancer, steatosis, inflammation, fibrosis, cholestasis, and xenobiotic/drug-induced liver injury. The network of target proteins associated with NRs is extremely complex, comprising coregulators, small noncoding microRNAs, and long noncoding RNAs. The importance of NRs as targets of liver disease is exemplified by the number of NR ligands that are currently used in the clinics or in clinical trials with promising results. Understanding the regulation by NR during pathophysiological conditions, and identifying ligands for orphan NR, points to a potential therapeutic approach for patients with liver diseases. An overview of complex NR metabolic networks and their pharmacological implications in liver disease is presented here.
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Affiliation(s)
- Swetha Rudraiah
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269
| | - Xi Zhang
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269
| | - Li Wang
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269.,Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516.,Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut 06520
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22
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Fungus-Derived Neoechinulin B as a Novel Antagonist of Liver X Receptor, Identified by Chemical Genetics Using a Hepatitis C Virus Cell Culture System. J Virol 2016; 90:9058-74. [PMID: 27489280 DOI: 10.1128/jvi.00856-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/20/2016] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Cell culture systems reproducing virus replication can serve as unique models for the discovery of novel bioactive molecules. Here, using a hepatitis C virus (HCV) cell culture system, we identified neoechinulin B (NeoB), a fungus-derived compound, as an inhibitor of the liver X receptor (LXR). NeoB was initially identified by chemical screening as a compound that impeded the production of infectious HCV. Genome-wide transcriptome analysis and reporter assays revealed that NeoB specifically inhibits LXR-mediated transcription. NeoB was also shown to interact directly with LXRs. Analysis of structural analogs suggested that the molecular interaction of NeoB with LXR correlated with the capacity to inactivate LXR-mediated transcription and to modulate lipid metabolism in hepatocytes. Our data strongly suggested that NeoB is a novel LXR antagonist. Analysis using NeoB as a bioprobe revealed that LXRs support HCV replication: LXR inactivation resulted in dispersion of double-membrane vesicles, putative viral replication sites. Indeed, cells treated with NeoB showed decreased replicative permissiveness for poliovirus, which also replicates in double-membrane vesicles, but not for dengue virus, which replicates via a distinct membrane compartment. Together, our data suggest that LXR-mediated transcription regulates the formation of virus-associated membrane compartments. Significantly, inhibition of LXRs by NeoB enhanced the activity of all known classes of anti-HCV agents, and NeoB showed especially strong synergy when combined with interferon or an HCV NS5A inhibitor. Thus, our chemical genetics analysis demonstrates the utility of the HCV cell culture system for identifying novel bioactive molecules and characterizing the virus-host interaction machinery. IMPORTANCE Hepatitis C virus (HCV) is highly dependent on host factors for efficient replication. In the present study, we used an HCV cell culture system to screen an uncharacterized chemical library. Our results identified neoechinulin B (NeoB) as a novel inhibitor of the liver X receptor (LXR). NeoB inhibited the induction of LXR-regulated genes and altered lipid metabolism. Intriguingly, our results indicated that LXRs are critical to the process of HCV replication: LXR inactivation by NeoB disrupted double-membrane vesicles, putative sites of viral replication. Moreover, NeoB augmented the antiviral activity of all known classes of currently approved anti-HCV agents without increasing cytotoxicity. Thus, our strategy directly links the identification of novel bioactive compounds to basic virology and the development of new antiviral agents.
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23
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Lim YS, Ngo HTT, Lee J, Son K, Park EM, Hwang SB. ADP-ribosylation Factor-related Protein 1 Interacts with NS5A and Regulates Hepatitis C Virus Propagation. Sci Rep 2016; 6:31211. [PMID: 27550144 PMCID: PMC4994002 DOI: 10.1038/srep31211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/08/2016] [Indexed: 12/12/2022] Open
Abstract
The life cycle of hepatitis C virus (HCV) is tightly coupled to the lipid metabolism of host cells. In order to identify host factors involved in HCV propagation, we have previously screened a small interfering RNA (siRNA) library targeting host genes that control lipid metabolism and lipid droplet (LD) formation using cell culture-grown HCV (HCVcc)-infected cells. In this study, we selected and characterized the gene encoding ADP-ribosylation factor-related protein 1 (ARFRP1). ARFRP1 is essential for LD growth and is involved in the regulation of lipolysis. siRNA-mediated knockdown of ARFRP1 significantly inhibited HCV replication in both subgenomic replicon cells and HCVcc-infected cells. ARFRP1 interacted with NS5A and NS5A partially colocalized with LD. Silencing of ARFRP1 abrogated HCV-induced LD growth and viral protein expressions. Moreover, ARFRP1 recruited synaptosomal-associated protein 23 (SNAP23) to sites in close proximity to LDs in HCV-infected cells. Silencing of ARFRP1 ablated relocalization of SNAP23 to LD. These data indicate that HCV regulates ARFRP1 for LD growth to facilitate viral propagation and thus ARFRP1 may be a potential target for antiviral therapy.
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Affiliation(s)
- Yun-Sook Lim
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Huong T T Ngo
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Jihye Lee
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Kidong Son
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
| | - Eun-Mee Park
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea.,Korea National Institute of Health, Cheongwon-gun, South Korea
| | - Soon B Hwang
- National Research Laboratory of Hepatitis C Virus and Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
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Sheng XX, Sun YJ, Zhan Y, Qu YR, Wang HX, Luo M, Liao Y, Qiu XS, Ding C, Fan HJ, Mao X. The LXR ligand GW3965 inhibits Newcastle disease virus infection by affecting cholesterol homeostasis. Arch Virol 2016; 161:2491-501. [PMID: 27357231 PMCID: PMC7087268 DOI: 10.1007/s00705-016-2950-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/22/2016] [Indexed: 12/12/2022]
Abstract
Newcastle disease (ND) is a contagious disease that affects most species of birds. Its causative pathogen, Newcastle disease virus (NDV), also exhibits considerable oncolytic activity against mammalian cancers. A better understanding of the pathogenesis of NDV will help us design efficient vaccines and novel anticancer strategies. GW3965, a widely used synthetic ligand of liver X receptor (LXR), induces the expression of LXRs and its downstream genes, including ATP-binding cassette transporter A1 (ABCA1). ABCA1 regulates cellular cholesterol homeostasis. Here, we found that GW3965 inhibited NDV infection in DF-1 cells. It also inhibited NF-κB activation and reduced the upregulation of proinflammatory cytokines induced by the infection. Further studies showed that GW3965 exerted its inhibitory effects on virus entry and replication. NDV infection increased the mRNA levels of several lipogenic genes but decreased the ABCA1 mRNA level. Overexpression of ABCA1 inhibited NDV infection and reduced the cholesterol content in DF-1 cells, but when the cholesterol was replenished, NDV infection was restored. GW3965 treatment prevented cholesterol accumulation in the perinuclear area of the infected cells. In summary, our studies suggest that GW3965 inhibits NDV infection, probably by affecting cholesterol homeostasis.
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Affiliation(s)
- Xiang-Xiang Sheng
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Ying-Jie Sun
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yuan Zhan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yu-Rong Qu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Hua-Xia Wang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Miao Luo
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Ying Liao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Xu-Sheng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
| | - Hong-Jie Fan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Xiang Mao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China. .,Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
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Ballestri S, Nascimbeni F, Romagnoli D, Baldelli E, Lonardo A. The Role of Nuclear Receptors in the Pathophysiology, Natural Course, and Drug Treatment of NAFLD in Humans. Adv Ther 2016; 33:291-319. [PMID: 26921205 DOI: 10.1007/s12325-016-0306-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Indexed: 02/06/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) describes steatosis, nonalcoholic steatohepatitis with or without fibrosis, and hepatocellular carcinoma, namely the entire alcohol-like spectrum of liver disease though observed in the nonalcoholic, dysmetabolic, individual free of competing causes of liver disease. NAFLD, which is a major public health issue, exhibits intrahepatic triglyceride storage giving rise to lipotoxicity. Nuclear receptors (NRs) are transcriptional factors which, activated by ligands, are master regulators of metabolism and also have intricate connections with circadian control accounting for cyclical patterns in the metabolic fate of nutrients. Several transcription factors, such as peroxisome proliferator-activated receptors, liver X receptors, farnesoid X receptors, and their molecular cascades, finely regulate energetic fluxes and metabolic pathways. Dysregulation of such pathways is heavily implicated in those metabolic derangements characterizing insulin resistance and metabolic syndrome and in the histogenesis of progressive NAFLD forms. We review the role of selected NRs in NAFLD pathogenesis. Secondly, we analyze the role of NRs in the natural history of human NAFLD. Next, we discuss the results observed in humans following administration of drug agonists or antagonists of the NRs pathogenically involved in NAFLD. Finally, general principles of treatment and lines of research in human NAFLD are briefly examined.
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Affiliation(s)
| | - Fabio Nascimbeni
- NOCSAE, Outpatient Liver Clinic and Operating Unit Internal Medicine, Azienda USL Modena, Modena, Italy
- University of Modena and Reggio Emilia, Modena, Italy
| | - Dante Romagnoli
- NOCSAE, Outpatient Liver Clinic and Operating Unit Internal Medicine, Azienda USL Modena, Modena, Italy
| | | | - Amedeo Lonardo
- NOCSAE, Outpatient Liver Clinic and Operating Unit Internal Medicine, Azienda USL Modena, Modena, Italy.
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Singaravelu R, O'Hara S, Jones DM, Chen R, Taylor NG, Srinivasan P, Quan C, Roy DG, Steenbergen RH, Kumar A, Lyn RK, Özcelik D, Rouleau Y, Nguyen MA, Rayner KJ, Hobman TC, Tyrrell DL, Russell RS, Pezacki JP. MicroRNAs regulate the immunometabolic response to viral infection in the liver. Nat Chem Biol 2015; 11:988-93. [DOI: 10.1038/nchembio.1940] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/11/2015] [Indexed: 12/12/2022]
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González-Reimers E, Quintero-Platt G, Rodríguez-Gaspar M, Alemán-Valls R, Pérez-Hernández O, Santolaria-Fernández F. Liver steatosis in hepatitis C patients. World J Hepatol 2015; 7:1337-1346. [PMID: 26052379 PMCID: PMC4450197 DOI: 10.4254/wjh.v7.i10.1337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 01/31/2015] [Accepted: 03/09/2015] [Indexed: 02/06/2023] Open
Abstract
There is controversy regarding some aspects of hepatitis C virus (HCV) infection-associated liver steatosis, and their relationship with body fat stores. It has classically been found that HCV, especially genotype 3, exerts direct metabolic effects which lead to liver steatosis. This supports the existence of a so called viral steatosis and a metabolic steatosis, which would affect HCV patients who are also obese or diabetics. In fact, several genotypes exert metabolic effects which overlap with some of those observed in the metabolic syndrome. In this review we will analyse the pathogenic pathways involved in the development of steatosis in HCV patients. Several cytokines and adipokines also become activated and are involved in “pure” steatosic effects, in addition to inflammation. They are probably responsible for the evolution of simple steatosis to steatohepatitis, making it difficult to explain why such alterations only affect a proportion of steatosic patients.
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Kurt R, Chandra PK, Aboulnasr F, Panigrahi R, Ferraris P, Aydin Y, Reiss K, Wu T, Balart LA, Dash S. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture. PLoS One 2015; 10:e0125962. [PMID: 25961570 PMCID: PMC4427131 DOI: 10.1371/journal.pone.0125962] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/27/2015] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α)-based combination therapy in chronic hepatitis C virus (HCV) infection. Previously, we reported that free fatty acid (FFA)-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1), which is why the antiviral activity of IFN-α against HCV is impaired. AIM To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment. METHOD HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate) and unsaturated (oleate) long-chain free fatty acids (FFA). Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α) and Type III IFN (IFN-λ) was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA) in the FFA-treated HCV cell culture model was investigated. RESULTS FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ), which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture. Pharmacological inhibitors of lysosomal degradation, such as ammonium chloride and bafilomycin, prevented IFNAR1 degradation in FFA-treated HCV cell culture. Activators of chaperone-mediated autophagy, including 6-aminonicotinamide and nutrient starvation, decreased IFNAR1 levels in Huh-7.5 cells. Co-immunoprecipitation, colocalization and siRNA knockdown experiments revealed that IFNAR1 but not IFNLR1 interacts with HSC70 and LAMP2A, which are core components of chaperone-mediated autophagy (CMA). CONCLUSION Our study presents evidence indicating that chaperone-mediated autophagy targets IFNAR1 degradation in the lysosome in FFA-treated HCV cell culture. These results provide a mechanism for why HCV induced autophagy response selectively degrades type I but not the type III IFNAR1.
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Affiliation(s)
- Ramazan Kurt
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Partha K. Chandra
- Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Fatma Aboulnasr
- Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Rajesh Panigrahi
- Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Pauline Ferraris
- Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Yucel Aydin
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Krzysztof Reiss
- Neurological Cancer Research, Stanley S Scott Cancer Center, LSU Health Science Center, New Orleans, Louisiana, United States of America
| | - Tong Wu
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Luis A. Balart
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Srikanta Dash
- Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
- Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
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Pisonero-Vaquero S, Martínez-Ferreras Á, García-Mediavilla MV, Martínez-Flórez S, Fernández A, Benet M, Olcoz JL, Jover R, González-Gallego J, Sánchez-Campos S. Quercetin ameliorates dysregulation of lipid metabolism genes via the PI3K/AKT pathway in a diet-induced mouse model of nonalcoholic fatty liver disease. Mol Nutr Food Res 2015; 59:879-93. [PMID: 25712622 DOI: 10.1002/mnfr.201400913] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/03/2015] [Accepted: 02/09/2015] [Indexed: 12/12/2022]
Abstract
SCOPE Flavonoids and related compounds seem to have favorable effects on nonalcoholic fatty liver disease (NAFLD) progression, although the exact mechanisms implicated are poorly understood. In this study, we aimed to investigate the effect of the flanovol quercetin on gene expression deregulation involved in the development of NAFLD, as well as the possible implication of phosphatidylinositol 3-kinase (PI3K)/AKT pathway modulation. METHODS AND RESULTS We used an in vivo model based on methionine- and choline-deficient (MCD) diet-fed mice and an in vitro model consisting of Huh7 cells incubated with MCD medium. MCD-fed mice showed classical pathophysiological characteristics of nonalcoholic steatohepatitis, associated with altered transcriptional regulation of fatty acid uptake- and trafficking-related gene expression, with increased lipoperoxidation. PI3K/AKT pathway was activated by MCD and triggered gene deregulation causing either activation or inhibition of all studied genes as demonstrated through cell incubation with the PI3K-inhibitor LY294002. Treatment with quercetin reduced AKT phosphorylation, and oxidative/nitrosative stress, inflammation and lipid metabolism-related genes displayed a tendency to normalize in both in vivo and in vitro models. CONCLUSION These results place quercetin as a potential therapeutic strategy for preventing NAFLD progression by attenuating gene expression deregulation, at least in part through PI3K/AKT pathway inactivation.
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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: 2.1] [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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Mahajan S, Saini A, Kalra R, Gupta P. Frienemies of infection: A chronic case of host nuclear receptors acting as cohorts or combatants of infection. Crit Rev Microbiol 2014; 42:526-34. [PMID: 25358058 DOI: 10.3109/1040841x.2014.970122] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Macrophages and dendritic cells provide critical effector functions to efficiently resist and promptly eliminate infection. Pattern recognition receptors signaling operative in these cell types is imperative for their innate properties. However, it is now emerging that besides these conventional signaling pathways, nuclear receptors coupled gene regulation and transrepression pathways assemble immune regulatory networks. A couple of these networks associated with members of nuclear receptor superfamily decide heterogeneity in macrophages and dendritic cells population and thereby play decisive role in determining protective immunity against bacteria, viruses, fungi, protozoa and helminths. Pathogens also direct shift in the expression of nuclear receptors and their target genes and this is proclaimed to be a sui generis mechanism whereby microbes disconnect the genomic component from the peripheral immune response. Many endogenous and synthetic nuclear receptor ligands have been tested in various in vitro and in vivo infection models to study their effect on pathogen burden. Here, we discuss current advances in our understanding of the composite interactions between nuclear receptor and pathogens and their implications on the causatum infectious diseases.
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Affiliation(s)
- Sahil Mahajan
- a Department of Molecular Biology , CSIR Institute of Microbial Technology , Chandigarh , India
| | - Ankita Saini
- a Department of Molecular Biology , CSIR Institute of Microbial Technology , Chandigarh , India
| | - Rashi Kalra
- a Department of Molecular Biology , CSIR Institute of Microbial Technology , Chandigarh , India
| | - Pawan Gupta
- a Department of Molecular Biology , CSIR Institute of Microbial Technology , Chandigarh , India
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Chen Z, Liu J, Fu Z, Ye C, Zhang R, Song Y, Zhang Y, Li H, Ying H, Liu H. 24(S)-Saringosterol from edible marine seaweed Sargassum fusiforme is a novel selective LXRβ agonist. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:6130-7. [PMID: 24927286 DOI: 10.1021/jf500083r] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Dietary phytosterols have been successfully used for lowering cholesterol levels, which correlates with the fact that some phytosterols are able to act as liver X receptor (LXR) agonists. Sargassum fusiforme is an edible marine seaweed well-known for its antiatherosclerotic function in traditional Chinese medicine. In this study, seven phytosterols including fucosterol (1), saringosterol (2), 24-hydroperoxy-24-vinyl-cholesterol (3), 29-hydroperoxy-stigmasta-5,24(28)-dien-3β-ol (4), 24-methylene-cholesterol (5), 24-keto-cholesterol (6), and 5α,8α-epidioxyergosta-6,22-dien-3β-ol (7) were purified and evaluated for their actions on LXR-mediated transcription using a reporter assay. Among these phytosterols, 2 was the most potent compound in stimulating the transcriptional activities of LXRα by (3.81±0.15)-fold and LXRβ by (14.40±1.10)-fold, respectively. Two epimers of 2, 24(S)-saringosterol (2a) and 24(R)-saringosterol (2b), were subsequently separated by semipreparative high-performance liquid chromatography. Interestingly, 2a was more potent than 2b in LXRβ-mediated transactivation ((3.50±0.17)-fold vs (1.63±0.12)-fold) compared with control. Consistently, 2a induced higher expression levels of LXR target genes including key players in reverse cholesterol transport in six cell lines. These data along with molecular modeling suggested that 2a acts as a selective LXRβ agonist and is a potent natural cholesterol-lowering agent. This study also demonstrated that phytosterols in S. fusiforme contributed to the well-known antiatherosclerotic function.
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Affiliation(s)
- Zhen Chen
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, Institute of Marine Food and Drugs, School of Medicine and Pharmacy, Ocean University of China , Qingdao 266003, China
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Li HC, Ma HC, Yang CH, Lo SY. Production and pathogenicity of hepatitis C virus core gene products. World J Gastroenterol 2014; 20:7104-7122. [PMID: 24966583 PMCID: PMC4064058 DOI: 10.3748/wjg.v20.i23.7104] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/05/2013] [Accepted: 04/03/2014] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic liver diseases, including steatosis, cirrhosis and hepatocellular carcinoma, and its infection is also associated with insulin resistance and type 2 diabetes mellitus. HCV, belonging to the Flaviviridae family, is a small enveloped virus whose positive-stranded RNA genome encoding a polyprotein. The HCV core protein is cleaved first at residue 191 by the host signal peptidase and further cleaved by the host signal peptide peptidase at about residue 177 to generate the mature core protein (a.a. 1-177) and the cleaved peptide (a.a. 178-191). Core protein could induce insulin resistance, steatosis and even hepatocellular carcinoma through various mechanisms. The peptide (a.a. 178-191) may play a role in the immune response. The polymorphism of this peptide is associated with the cellular lipid drop accumulation, contributing to steatosis development. In addition to the conventional open reading frame (ORF), in the +1 frame, an ORF overlaps with the core protein-coding sequence and encodes the alternative reading frame proteins (ARFP or core+1). ARFP/core+1/F protein could enhance hepatocyte growth and may regulate iron metabolism. In this review, we briefly summarized the current knowledge regarding the production of different core gene products and their roles in viral pathogenesis.
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Zhu W, Pei R, Jin R, Hu X, Zhou Y, Wang Y, Wu C, Lu M, Chen X. Nuclear receptor 4 group A member 1 determines hepatitis C virus entry efficiency through the regulation of cellular receptor and apolipoprotein E expression. J Gen Virol 2014; 95:1510-1521. [PMID: 24744301 DOI: 10.1099/vir.0.065003-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Orphan nuclear receptor subfamily 4 group A member 1 (NR4A1) is a transcription factor stimulated by many factors and plays pivotal roles in metabolism, proliferation and apoptosis. In this study, the expression of NR4A1 in Huh7.5.1 cells was significantly upregulated by hepatitis C virus (HCV) infection. The silencing of NR4A1 inhibited the entry of HCV and reduced the specific infectivity of secreted HCV particles but had only minor or no effect on the genome replication and translation, virion assembly and virus release steps of the virus life cycle. Further experiments demonstrated that the silencing of NR4A1 affected virus entry through pan-downregulation of the expression of HCV receptors scavenger receptor BI, occludin, claudin-1 and epidermal growth factor receptor but not CD81. The reduced specific infectivity of HCV in the knockdown cells was due to decreased apolipoprotein E (ApoE) expression. These results explain the delayed spread of HCV in NR4A1 knockdown Huh7.5.1 cells. Thus, NR4A1 plays a role in HCV replication through regulating the expression of HCV receptors and ApoE, and facilitates HCV entry and spread.
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Affiliation(s)
- Wandi Zhu
- University of Chinese Academy of Sciences, Beijing, PR China
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Rongjuan Pei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Rui Jin
- University of Chinese Academy of Sciences, Beijing, PR China
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Xue Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Yuan Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Yun Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Chunchen Wu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Mengji Lu
- Institute of Virology, University hospital Essen, University of Duisburg-Essen, Essen, Germany
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
| | - Xinwen Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, PR China
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Abstract
PURPOSE OF REVIEW Circulating levels of cholesterol precursors in the body have proven their value over the years as indicators of in-vivo cholesterol synthesis. However, there is growing interest in their potential as markers of various disease states. The purpose of this review is to evaluate current literature on cholesterol precursors as disease markers. RECENT FINDINGS Firstly, we focus on studies linking circulating squalene with the risk of cardiovascular disease. Secondly, we explore the interplay between cholesterol precursors (7-dehydrocholesterol and desmosterol) and the enzymes that act upon them (DHCR7 and DHCR24) in the context of liver disease. For instance, recent findings indicate that circulating desmosterol is elevated in nonalcoholic steatohepatitis. This may be linked to this regulatory cholesterol precursor being produced in and effluxed from hepatocytes, or alternatively from lipid-laden hepatic macrophages (Kupffer cells), which play an important role in the cause of nonalcoholic steatohepatitis. Desmosterol is also implicated in Hepatitis C virus replication, and hence may also be involved in viral fatty liver disease, possibly contributing to virus pathogenicity and/or host defense. Furthermore, there is increasing evidence that the activity of DHCR7 may affect chronic liver diseases by influencing vitamin D levels. SUMMARY Beyond their accepted application as markers of cholesterol synthesis, cholesterol precursors have potential both as disease indicators, and for providing deeper insights into the disease process.
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Affiliation(s)
- Andrew J Brown
- aSchool of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia bInstitute of Biomedicine, Anatomy, University of Helsinki cMinerva Foundation Institute for Medical Research, Helsinki, Finland
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Georgopoulou U, Dimitriadis A, Foka P, Karamichali E, Mamalaki A. Hepcidin and the iron enigma in HCV infection. Virulence 2014; 5:465-76. [PMID: 24626108 PMCID: PMC4063809 DOI: 10.4161/viru.28508] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
An estimated 30-40% of patients with chronic hepatitis C have elevated serum iron, transferrin saturation, and ferritin levels. Clinical data suggest that iron is a co-morbidity factor for disease progression following HCV infection. Iron is essential for a number of fundamental metabolic processes in cells and organisms. Mammalian iron homeostasis is tightly regulated and this is maintained through the coordinated action of sensory and regulatory networks that modulate the expression of iron-related proteins at the transcriptional and/or posttranscriptional levels. Disturbances of iron homeostasis have been implicated in infectious disease pathogenesis. Viruses, similarly to other pathogens, can escape recognition by the immune system, but they need iron from their host to grow and spread. Hepcidin is a 25-aa peptide, present in human serum and urine and represents the key peptide hormone, which modulates iron homeostasis in the body. It is synthesized predominantly by hepatocytes and its mature form is released in circulation. In this review, we discuss recent advances in the exciting crosstalk of molecular mechanisms and cell signaling pathways by which iron and hepcidin production influences HCV-induced liver disease.
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Affiliation(s)
- Urania Georgopoulou
- Laboratory of Molecular Virology; Hellenic Pasteur Institute; Athens, Greece
| | - Alexios Dimitriadis
- Laboratory of Molecular Biology and Immunobiotechnology; Hellenic Pasteur Institute; Athens, Greece
| | - Pelagia Foka
- Laboratory of Molecular Virology; Hellenic Pasteur Institute; Athens, Greece; Laboratory of Molecular Biology and Immunobiotechnology; Hellenic Pasteur Institute; Athens, Greece
| | - Eirini Karamichali
- Laboratory of Molecular Virology; Hellenic Pasteur Institute; Athens, Greece
| | - Avgi Mamalaki
- Laboratory of Molecular Biology and Immunobiotechnology; Hellenic Pasteur Institute; Athens, Greece
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Pisonero-Vaquero S, García-Mediavilla MV, Jorquera F, Majano PL, Benet M, Jover R, González-Gallego J, Sánchez-Campos S. Modulation of PI3K-LXRα-dependent lipogenesis mediated by oxidative/nitrosative stress contributes to inhibition of HCV replication by quercetin. J Transl Med 2014; 94:262-74. [PMID: 24492281 DOI: 10.1038/labinvest.2013.156] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 11/28/2013] [Accepted: 12/23/2013] [Indexed: 02/07/2023] Open
Abstract
There is experimental evidence that some antioxidant flavonoids show therapeutic potential in the treatment of hepatitis C through inhibition of hepatitis C virus (HCV) replication. We examined the effect of treatment with the flavonols quercetin and kaempferol, the flavanone taxifolin and the flavone apigenin on HCV replication efficiency in an in vitro model. While all flavonoids studied were able to reduce viral replication at very low concentrations (ranging from 0.1 to 5 μM), quercetin appeared to be the most effective inhibitor of HCV replication, showing a marked anti-HCV activity in replicon-containing cells when combined with interferon (IFN)α. The contribution of oxidative/nitrosative stress and lipogenesis modulation to inhibition of HCV replication by quercetin was also examined. As expected, quercetin decreased HCV-induced reactive oxygen and nitrogen species (ROS/RNS) generation and lipoperoxidation in replicating cells. Quercetin also inhibited liver X receptor (LXR)α-induced lipid accumulation in LXRα-overexpressing and replicon-containing Huh7 cells. The mechanism underlying the LXRα-dependent lipogenesis modulatory effect of quercetin in HCV-replicating cells seems to involve phosphatidylinositol 3-kinase (PI3K)/AKT pathway inactivation. Thus, inhibition of the PI3K pathway by LY294002 attenuated LXRα upregulation and HCV replication mediated by lipid accumulation, showing an additive effect when combined with quercetin. Inactivation of the PI3K pathway by quercetin may contribute to the repression of LXRα-dependent lipogenesis and to the inhibition of viral replication induced by the flavonol. Combined, our data suggest that oxidative/nitrosative stress blockage and subsequent modulation of PI3K-LXRα-mediated lipogenesis might contribute to the inhibitory effect of quercetin on HCV replication.
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Affiliation(s)
| | - María V García-Mediavilla
- 1] Institute of Biomedicine (IBIOMED), University of León, León, Spain [2] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Francisco Jorquera
- 1] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain [2] Department of Gastroenterology, Complejo Asistencial Universitario de León, León, Spain
| | - Pedro L Majano
- 1] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain [2] Molecular Biology Unit, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Princesa (IP), Madrid, Spain
| | - Marta Benet
- 1] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain [2] Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain
| | - Ramiro Jover
- 1] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain [2] Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain [3] Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain
| | - Javier González-Gallego
- 1] Institute of Biomedicine (IBIOMED), University of León, León, Spain [2] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Sonia Sánchez-Campos
- 1] Institute of Biomedicine (IBIOMED), University of León, León, Spain [2] Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
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Hepatitis C virus modulates lipid regulatory factor Angiopoietin-like 3 gene expression by repressing HNF-1α activity. J Hepatol 2014; 60:30-8. [PMID: 23978712 DOI: 10.1016/j.jhep.2013.08.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/30/2013] [Accepted: 08/10/2013] [Indexed: 01/02/2023]
Abstract
BACKGROUND & AIMS HCV relies on host lipid metabolism to complete its life cycle and HCV core is crucial to this interaction. Liver secreted ANGPTL-3 is an LXR- and HNF-1α-regulated protein, which plays a key role in lipid metabolism by increasing plasma lipids via inhibition of lipase enzymes. Here we aimed to investigate the modulation of ANGPTL-3 by HCV core and identify the molecular mechanisms involved. METHODS qRT-PCR and ELISA were used to assess ANGPTL-3 mRNA and protein levels in HCV patients, the JFH-1 infectious system and liver cell lines. Transfections, chromatin immunoprecipitation and immunofluorescence delineated parts of the molecular mechanisms implicated in the core-mediated regulation of ANGPTL-3 gene expression. RESULTS ANGPTL-3 gene expression was decreased in HCV-infected patients and the JFH-1 infectious system. mRNA and promoter activity levels were down-regulated by core. The response was lost when an HNF-1α element in ANGPTL-3 promoter was mutated, while loss of HNF-1α DNA binding to this site was recorded in the presence of HCV core. HNF-1α mRNA and protein levels were not altered by core. However, trafficking between nucleus and cytoplasm was observed and then blocked by an inhibitor of the HNF-1α-specific kinase Mirk/Dyrk1B. Transactivation of LXR/RXR signalling could not restore core-mediated down-regulation of ANGPTL-3 promoter activity. CONCLUSIONS ANGPTL-3 is negatively regulated by HCV in vivo and in vitro. HCV core represses ANGPTL-3 expression through loss of HNF-1α binding activity and blockage of LXR/RXR transactivation. The putative ensuing increase in serum lipid clearance and uptake by the liver may sustain HCV virus replication and persistence.
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Nasheri N, Joyce M, Rouleau Y, Yang P, Yao S, Tyrrell DL, Pezacki JP. Modulation of fatty acid synthase enzyme activity and expression during hepatitis C virus replication. ACTA ACUST UNITED AC 2013; 20:570-82. [PMID: 23601646 DOI: 10.1016/j.chembiol.2013.03.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/22/2013] [Accepted: 03/19/2013] [Indexed: 02/07/2023]
Abstract
The hepatitis C virus (HCV) induces alterations of host cells to facilitate its life cycle. Fatty acid synthase (FASN) is a multidomain enzyme that plays a key role in the biosynthesis of fatty acids and is upregulated during HCV infection. Herein, we applied activity-based protein profiling (ABPP) that allows for the identification of differentially active enzymes in complex proteomic samples, to study the changes in activity of FASN during HCV replication. For this purpose, we used an activity-based probe based on the FASN inhibitor Orlistat, and observed an increase in the activity of FASN in the presence of a subgenomic and a genomic HCV replicon as well as in chimeric SCID/Alb-uPA mice infected with HCV genotype 1a. To study the molecular basis for this increase in FASN activity, we overexpressed individual HCV proteins in Huh7 cells and observed increased expression and activity of FASN in the presence of core and NS4B, as measured by western blots and ABPP, respectively. Triglyceride levels were also elevated in accordance with FASN expression and activity. Lastly, immunofluorescence and ABPP imaging analyses demonstrated that while the abundance and activity of FASN increases significantly in the presence of HCV, its localization does not change. Together these data suggest that the HCV-induced production of fatty acids and neutral lipids is provided by an increase in FASN abundance and activity that is sufficient to allow HCV propagation without transporting FASN to the replication complexes.
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Affiliation(s)
- Neda Nasheri
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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Dillon ST, Bhasin MK, Feng X, Koh DW, Daoud SS. Quantitative proteomic analysis in HCV-induced HCC reveals sets of proteins with potential significance for racial disparity. J Transl Med 2013; 11:239. [PMID: 24283668 PMCID: PMC3850534 DOI: 10.1186/1479-5876-11-239] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/28/2013] [Indexed: 12/18/2022] Open
Abstract
Background The incidence and mortality of hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) is higher in African Americans (AA) than other racial/ethnic groups in the U.S., but the reasons for this disparity are unknown. There is an urgent need for the discovery of novel molecular signatures for HCV disease progression to understand the underlying biological basis for this cancer rate disparity to improve the clinical outcome. Methods We performed differential proteomics with isobaric labeling tags for relative and absolute quantitation (iTRAQ) and MS/MS analysis to identify proteins differentially expressed in cirrhotic (CIR) and HCC as compared to normal tissues of Caucasian American (CA) patients. The raw data were analyzed using the ProteinPilot v3.0. Searches were performed against all known sequences populating the Swiss-Prot, Refseq, and TrEMBL databases. Quality control analyses were accomplished using pairwise correlation plots, boxplots, principal component analysis, and unsupervised hierarchical clustering. Supervised analysis was carried out to identify differentially expressed proteins. Candidates were validated in independent cohorts of CA and AA tissues by qRT-PCR or Western blotting. Results A total of 238 unique proteins were identified. Of those, around 15% were differentially expressed between normal, CIR & HCC groups. Target validation demonstrates racially distinct alteration in the expression of certain proteins. For example, the mRNA expression levels of transferrin (TF) were 2 and18-fold higher in CIR and HCC in AA as compared to CA. Similarly; the expression of Apolipoprotein A1 (APOA1) was 7-fold higher in HCC of AA. This increase was mirrored in the protein expression levels. Interestingly, the level of hepatocyte nuclear factor4α (HNF4α) protein was down regulated in AA, whereas repression of transcription is seen more in CA compared to AA. These data suggest that racial disparities in HCC could be a consequence of differential dysregulation of HNF4α transcriptional activity. Conclusion This study identifies novel molecular signatures in HCV-induced HCC using iTRAQ-based tissue proteomics. The proteins identified will further enhance a molecular explanation to the biochemical mechanism(s) that may play a role in HCC racial disparities.
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Steffensen KR, Jakobsson T, Gustafsson JÅ. Targeting liver X receptors in inflammation. Expert Opin Ther Targets 2013; 17:977-90. [PMID: 23738533 DOI: 10.1517/14728222.2013.806490] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION The two oxysterol receptors, 'liver X receptors (LXRs)' LXRα and LXRβ, are amongst the emerging newer drug targets within the nuclear receptor family and targeting LXRs represents novel strategies needed for prevention and treatment of diseases where current therapeutics is inadequate. AREAS COVERED This review discusses the current understanding of LXR biology with an emphasis on the molecular aspects of LXR signalling establishing their potential as drug targets. Recent advances of their transcriptional mechanisms in inflammatory pathways and their physiological roles in inflammation and immunity are described. EXPERT OPINION The new discoveries of LXR-regulated inflammatory pathways have ignited new promises for LXRs as drug targets. The broad physiological roles of LXRs involve a high risk of unwanted side effects. Recent insights into LXR biology of the brain indicate a highly important role in neuronal development and a clinical trial testing an LXR agonist reported adverse neurological side effects. This suggests that drug development must focus on limiting the range of LXR signalling - possibly achieved through subtype, tissue specific, promoter specific or pathway specific activation of LXRs where a successful candidate drug must be carefully studied for its effect in the central nervous system.
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Affiliation(s)
- Knut R Steffensen
- Karolinska Institutet, Center for Biosciences, Department of Biosciences and Nutrition, S-14183 Stockholm, Sweden.
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42
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Guzmán C, Benet M, Pisonero-Vaquero S, Moya M, García-Mediavilla MV, Martínez-Chantar ML, González-Gallego J, Castell JV, Sánchez-Campos S, Jover R. The human liver fatty acid binding protein (FABP1) gene is activated by FOXA1 and PPARα; and repressed by C/EBPα: Implications in FABP1 down-regulation in nonalcoholic fatty liver disease. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:803-18. [PMID: 23318274 DOI: 10.1016/j.bbalip.2012.12.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/22/2012] [Accepted: 12/27/2012] [Indexed: 01/24/2023]
Abstract
Liver fatty acid binding protein (FABP1) prevents lipotoxicity of free fatty acids and regulates fatty acid trafficking and partition. Our objective is to investigate the transcription factors controlling the human FABP1 gene and their regulation in nonalcoholic fatty liver disease (NAFLD). Adenovirus-mediated expression of multiple transcription factors in HepG2 cells and cultured human hepatocytes demonstrated that FOXA1 and PPARα are among the most effective activators of human FABP1, whereas C/EBPα is a major dominant repressor. Moreover, FOXA1 and PPARα induced re-distribution of FABP1 protein and increased cytoplasmic expression. Reporter assays demonstrated that the major basal activity of the human FABP1 promoter locates between -96 and -229bp, where C/EBPα binds to a composite DR1-C/EBP element. Mutation of this element at -123bp diminished basal reporter activity, abolished repression by C/EBPα and reduced transactivation by HNF4α. Moreover, HNF4α gene silencing by shRNA in HepG2 cells caused a significant down-regulation of FABP1 mRNA expression. FOXA1 activated the FABP1 promoter through binding to a cluster of elements between -229 and -592bp, whereas PPARα operated through a conserved proximal element at -59bp. Finally, FABP1, FOXA1 and PPARα were concomitantly repressed in animal models of NAFLD and in human nonalcoholic fatty livers, whereas C/EBPα was induced or did not change. We conclude that human FABP1 has a complex mechanism of regulation where C/EBPα displaces HNF4α and hampers activation by FOXA1 and PPARα. Alteration of expression of these transcription factors in NAFLD leads to FABP1 gen repression and could exacerbate lipotoxicity and disease progression.
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Affiliation(s)
- Carla Guzmán
- Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain
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Crespo I, San-Miguel B, Prause C, Marroni N, Cuevas MJ, González-Gallego J, Tuñón MJ. Glutamine treatment attenuates endoplasmic reticulum stress and apoptosis in TNBS-induced colitis. PLoS One 2012; 7:e50407. [PMID: 23209735 PMCID: PMC3508929 DOI: 10.1371/journal.pone.0050407] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/18/2012] [Indexed: 12/23/2022] Open
Abstract
Endoplasmic reticulum (ER) stress and apoptotic cell death play an important role in the pathogenesis and perpetuation of inflammatory bowel disease (IBD). We aimed to explore the potential of glutamine to reduce ER stress and apoptosis in a rat model of experimental IBD. Colitis was induced in male Wistar rats by intracolonic administration of 30 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS). Glutamine (25 mg/dL) was given by rectal route daily for 2 d or 7 d. Both oxidative stress (TBARS concentration and oxidised/reduced glutathione ratio) and ER stress markers (CHOP, BiP, calpain-1 and caspase-12 expression) increased significantly within 48 h of TNBS instillation, and glutamine attenuated the extent of the changes. Glutamine also inhibited the significant increases of ATF6, ATF4 and spliced XBP-1 mRNA levels induced by TNBS instillation. TNBS-colitis resulted in a significant increase in p53 and cytochrome c expression, and a reduced Bcl-xL expression and Bax/Bcl-2 ratio. These effects were significantly inhibited by glutamine. Treatment with the amino acid also resulted in significant decreases of caspase-9, caspase-8 and caspase-3 activities. Double immunofluorescence staining showed co-localization of CHOP and cleaved caspase-3 in colon sections. Phospho-JNK and PARP-1 expression was also significantly higher in TNBS-treated rats, and treatment with glutamine significantly decreased JNK phosphorylation and PARP-1 proteolysis. To directly address the effect of glutamine on ER stress and apoptosis in epithelial cells, the ER stress inducers brefeldin A and tunicamycin were added to Caco-2 cells that were treated with glutamine (5 mM and 10 mM). The significant enhancement in PERK, ATF6 phosphorylated IRE1, BiP and cleaved caspase-3 expression induced by brefeldin A and tunicamycin was partly prevented by glutamine. Data obtained indicated that modulation of ER stress signalling and anti-apoptotic effects contribute to protection by glutamine against damage in TNBS-induced colitis.
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Affiliation(s)
- Irene Crespo
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain
- Institute of Biomedicine (IBIOMED), University of León, León, Spain
| | | | - Carolina Prause
- Institute of Biomedicine (IBIOMED), University of León, León, Spain
| | - Norma Marroni
- Porto Alegre Clinical Hospital, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - María J. Cuevas
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain
- Institute of Biomedicine (IBIOMED), University of León, León, Spain
| | - Javier González-Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain
- Institute of Biomedicine (IBIOMED), University of León, León, Spain
| | - María J. Tuñón
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), León, Spain
- Institute of Biomedicine (IBIOMED), University of León, León, Spain
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Peyrou M, Ramadori P, Bourgoin L, Foti M. PPARs in Liver Diseases and Cancer: Epigenetic Regulation by MicroRNAs. PPAR Res 2012; 2012:757803. [PMID: 23024649 PMCID: PMC3449131 DOI: 10.1155/2012/757803] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 06/27/2012] [Indexed: 12/19/2022] Open
Abstract
Peroxisome-proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors that exert in the liver a transcriptional activity regulating a whole spectrum of physiological functions, including cholesterol and bile acid homeostasis, lipid/glucose metabolism, inflammatory responses, regenerative mechanisms, and cell differentiation/proliferation. Dysregulations of the expression, or activity, of specific PPAR isoforms in the liver are therefore believed to represent critical mechanisms contributing to the development of hepatic metabolic diseases, disorders induced by hepatic viral infections, and hepatocellular adenoma and carcinoma. In this regard, specific PPAR agonists have proven to be useful to treat these metabolic diseases, but for cancer therapies, the use of PPAR agonists is still debated. Interestingly, in addition to previously described mechanisms regulating PPARs expression and activity, microRNAs are emerging as new important regulators of PPAR expression and activity in pathophysiological conditions and therefore may represent future therapeutic targets to treat hepatic metabolic disorders and cancers. Here, we reviewed the current knowledge about the general roles of the different PPAR isoforms in common chronic metabolic and infectious liver diseases, as well as in the development of hepatic cancers. Recent works highlighting the regulation of PPARs by microRNAs in both physiological and pathological situations with a focus on the liver are also discussed.
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Affiliation(s)
- Marion Peyrou
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Pierluigi Ramadori
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Lucie Bourgoin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
| | - Michelangelo Foti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, Centre Médical Universiatire (CMU), 1206 Geneva, Switzerland
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