1
|
Pattabhi S, Knoll ML, Gale M, Loo YM. DHX15 Is a Coreceptor for RLR Signaling That Promotes Antiviral Defense Against RNA Virus Infection. J Interferon Cytokine Res 2019; 39:331-346. [PMID: 31090472 PMCID: PMC6590726 DOI: 10.1089/jir.2018.0163] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/01/2019] [Indexed: 12/23/2022] Open
Abstract
RNA helicases play an important role in the response to microbial infection. Retinoic acid inducible gene-I (RIG-I) and members of the RIG-I-like receptor (RLR) family of helicases function as cytoplasmic pattern recognition receptors (PRRs) whose actions are essential for recognition of RNA viruses. RIG-I association with pathogen-associated molecular patterns (PAMPs) within viral RNA leads to its activation and signaling via the mitochondrial antiviral signaling (MAVS) adapter protein. This interaction mediates downstream signaling events that drive the innate immune response to virus infection. Here we identify the DEAH-box RNA helicase DHX15 as a RLR binding partner and signaling cofactor. In human cells, DHX15 is required for virus-induced RLR signaling of innate immune gene expression. Knockdown of DHX15 increased susceptibility to infection by RNA viruses of diverse genera, including Paramyxoviridae, Rhabdoviridae, and Picornaviridae. DHX15 associates with RIG-I caspase activation and recruitment domains (CARDs) through its amino terminus, in which the complex is recruited to MAVS on virus infection. Importantly, although DHX15 cannot substitute for RIG-I in innate immune signaling, DHX15 selectively binds PAMP RNA to promote RIG-I ATP hydrolysis and signaling activation in response to viral RNA. Our results define DHX15 as a coreceptor required for RLR innate immune responses to control RNA virus infection.
Collapse
Affiliation(s)
- Sowmya Pattabhi
- Department of Global Health, University of Washington, Seattle, Washington
- Department of Immunology, Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington
| | - Megan L. Knoll
- Department of Immunology, Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington
- Department of Immunology, University of Washington, Seattle, Washington
| | - Michael Gale
- Department of Global Health, University of Washington, Seattle, Washington
- Department of Immunology, Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington
- Department of Immunology, University of Washington, Seattle, Washington
| | - Yueh-Ming Loo
- Department of Immunology, Center for Innate Immunity and Immune Disease, University of Washington, Seattle, Washington
- Department of Immunology, University of Washington, Seattle, Washington
| |
Collapse
|
2
|
Funaki M, Kitabayashi J, Shimakami T, Nagata N, Sakai Y, Takegoshi K, Okada H, Murai K, Shirasaki T, Oyama T, Yamashita T, Ota T, Takuwa Y, Honda M, Kaneko S. Peretinoin, an acyclic retinoid, inhibits hepatocarcinogenesis by suppressing sphingosine kinase 1 expression in vitro and in vivo. Sci Rep 2017; 7:16978. [PMID: 29208982 PMCID: PMC5717167 DOI: 10.1038/s41598-017-17285-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/22/2017] [Indexed: 02/07/2023] Open
Abstract
Sphingosine-1-phospate is a potent bioactive lipid metabolite that regulates cancer progression. Because sphingosine kinase 1 and sphingosine kinase 2 (SPHK 1/2) are both essential for sphingosine-1-phospate production, they could be a therapeutic target in various cancers. Peretinoin, an acyclic retinoid, inhibits post-therapeutic recurrence of hepatocellular carcinoma via unclear mechanisms. In this study, we assessed effects of peretinoin on SPHK expression and liver cancer development in vitro and in vivo. We examined effects of peretinoin on expression, enzymatic and promoter activity of SPHK1 in a human hepatoma cell line, Huh-7. We also investigated effects of SPHK1 on hepatocarcinogenesis induced by diethylnitrosamine using SPHK1 knockout mice. Peretinoin treatment of Huh-7 cells reduced mRNA levels, protein expression and enzymatic activity of SPHK1. Peretinoin reduced SPHK1 promoter activity; this effect of peretinoin was blocked by overexpression of Sp1, a transcription factor. Deletion of all Sp1 binding sites within the SPHK1 promoter region abolished SPHK1 promoter activity, suggesting that peretinoin reduced mRNA levels of SPHK1 via Sp1. Additionally, diethylnitrosamine-induced hepatoma was fewer and less frequent in SPHK1 knockout compared to wild-type mice. Our data showed crucial roles of SPHK1 in hepatocarcinogenesis and suggests that peretinoin prevents hepatocarcinogenesis by suppressing mRNA levels of SPHK1.
Collapse
Affiliation(s)
- Masaya Funaki
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Juria Kitabayashi
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Tetsuro Shimakami
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan.
| | - Naoto Nagata
- Advanced Preventive Medical Sciences Research Center, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yuriko Sakai
- Advanced Preventive Medical Sciences Research Center, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kai Takegoshi
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hikari Okada
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kazuhisa Murai
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Takayoshi Shirasaki
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Takeru Oyama
- Department of Molecular and Cellular Pathology, Graduate School of Medical Science, Kanazawa University, Ishikawa, Japan
| | - Taro Yamashita
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Tsuguhito Ota
- Advanced Preventive Medical Sciences Research Center, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoh Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan
| | - Masao Honda
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Shuichi Kaneko
- Department of Gastroenterology, Kanazawa University, Kanazawa, Ishikawa, Japan
| |
Collapse
|
3
|
Liu F, Shimakami T, Murai K, Shirasaki T, Funaki M, Honda M, Murakami S, Yi M, Tang H, Kaneko S. Efficient Suppression of Hepatitis C Virus Replication by Combination Treatment with miR-122 Antagonism and Direct-acting Antivirals in Cell Culture Systems. Sci Rep 2016; 6:30939. [PMID: 27484655 PMCID: PMC4971519 DOI: 10.1038/srep30939] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/11/2016] [Indexed: 02/05/2023] Open
Abstract
Direct-acting antivirals (DAAs) against Hepatitis C virus (HCV) show effective antiviral activity with few side effects. However, the selection of DAA-resistance mutants is a growing problem that needs to be resolved. In contrast, miR-122 antagonism shows extensive antiviral effects among all HCV genotypes and a high barrier to drug resistance. In the present study, we evaluated three DAAs (simeprevir, daclatasvir, and sofosbuvir) in combination with anti-miR-122 treatment against HCV genotype 1a in cell cultures. We found that combination treatments with anti-miR-122 and a DAA had additive or synergistic antiviral effects. The EC50 values of simeprevir in simeprevir-resistant mutants were significantly decreased by combining simeprevir with anti-miR-122. A similar reduction in EC50 in daclatasvir-resistant mutants was achieved by combining daclatasvir with anti-miR-122. Combination treatment in HCV-replicating cells with DAA and anti-miR-122 sharply reduced HCV RNA amounts. Conversely, DAA single treatment with simeprevir or daclatasvir reduced HCV RNA levels initially, but the levels later rebounded. DAA-resistant mutants were less frequently observed in combination treatments than in DAA single treatments. In summary, the addition of miR-122 antagonism to DAA single treatments had additive or synergistic antiviral effects and helped to efficiently suppress HCV replication and the emergence of DAA-resistant mutants.
Collapse
Affiliation(s)
- Fanwei Liu
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Tetsuro Shimakami
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Kazuhisa Murai
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Takayoshi Shirasaki
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Masaya Funaki
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Masao Honda
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Seishi Murakami
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| | - Minkyung Yi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555-0144, USA
| | - Hong Tang
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shuichi Kaneko
- Department of Gastroenterology, Kanazawa University Hospital, Kanazawa, Ishikawa 920-8641, Japan
| |
Collapse
|
4
|
Brito-Zerón P, Gheitasi H, Retamozo S, Bové A, Londoño M, Sánchez-Tapias JM, Caballero M, Kostov B, Forns X, Kaveri SV, Ramos-Casals M. How hepatitis C virus modifies the immunological profile of Sjögren syndrome: analysis of 783 patients. Arthritis Res Ther 2015; 17:250. [PMID: 26370711 PMCID: PMC4570241 DOI: 10.1186/s13075-015-0766-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/24/2015] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION We conducted a study to analyze how infection by hepatitis C virus (HCV) may influence the immunological serum pattern of patients with Sjögren syndrome (SS). METHODS Since 1994, we have tested serum HCV-IgG antibodies in 783 patients with SS diagnosed according to the 1993 European classification criteria. The immunological profile at diagnosis was compared according to the presence or absence of HCV. RESULTS Of the 783 patients with SS, 105 (13.4 %) tested positive for HCV-IgG antibodies (88 females, 17 males, mean age at SS diagnosis: 62.9 years). Multivariate analysis showed that patients with SS-HCV had a higher mean age and a higher frequency of low C3/C4 levels, cryoglobulins, and hematological neoplasia compared with patients without HCV. The frequency of anti-La antibodies compared with anti-Ro antibodies was higher in patients with SS-HCV (17 % vs. 15 %) and lower in patients without HCV infection (30 % vs. 43 %). The frequency of concomitant detection of the three main cryoglobulin-related markers (cryoglobulins, rheumatoid factor activity, and C4 consumption) was threefold higher in patients with SS-HCV compared with patients without HCV. SS-HCV patients with genotype 1b showed the highest frequencies of immunological abnormalities related to cryoglobulins and the lowest frequencies of anti-Ro/La antibodies. CONCLUSIONS We found HCV infection in 13 % of a large series of Spanish patients with SS. The HCV-driven autoimmune response was characterized by a lower frequency of anti-Ro/La antibodies, an abnormal predominance of anti-La among anti-Ro antibodies, and a higher frequency of cryoglobulinemic-related immunological markers in comparison with patients without HCV infection. This immunological pattern may contribute to the poor outcomes found in patients with SS-HCV.
Collapse
Affiliation(s)
- Pilar Brito-Zerón
- Josep Font Autoimmune Diseases Laboratory, CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/ Villarroel 170, Barcelona, 08036, Spain.
- Department of Autoimmune Diseases, Hospital Clínic, University of Barcelona, C/Villarroel, 170, 08036, Barcelona, Spain.
| | - Hoda Gheitasi
- Josep Font Autoimmune Diseases Laboratory, CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Soledad Retamozo
- Josep Font Autoimmune Diseases Laboratory, CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Albert Bové
- Josep Font Autoimmune Diseases Laboratory, CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/ Villarroel 170, Barcelona, 08036, Spain.
| | - María Londoño
- Viral Hepatitis Unit, Liver Unit, CIBERehd, Hospital Clínic, University of Barcelona, IDIBAPS, C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Jose-Maria Sánchez-Tapias
- Viral Hepatitis Unit, Liver Unit, CIBERehd, Hospital Clínic, University of Barcelona, IDIBAPS, C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Miguel Caballero
- ENT Department, Hospital Clínic, University of Barcelona, IDIBAPS, C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Belchin Kostov
- Primary Care Research Group, IDIBAPS, Primary Care Centre Les Corts, CAPSE, Mejia Lequerica, s / n, Barcelona, 08028, Spain.
| | - Xavier Forns
- Viral Hepatitis Unit, Liver Unit, CIBERehd, Hospital Clínic, University of Barcelona, IDIBAPS, C/ Villarroel 170, Barcelona, 08036, Spain.
| | - Srini V Kaveri
- Immunopathology and Therapeutic Immunointervention, Centre de Recherche des Cordeliers, INSERM, 15 Rue de l'Ecole de Medecine, Paris, F-75006, France.
| | - Manuel Ramos-Casals
- Josep Font Autoimmune Diseases Laboratory, CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C/ Villarroel 170, Barcelona, 08036, Spain.
- Department of Autoimmune Diseases, Hospital Clínic, University of Barcelona, C/Villarroel, 170, 08036, Barcelona, Spain.
| |
Collapse
|
5
|
Carrozzo M, Scally K. Oral manifestations of hepatitis C virus infection. World J Gastroenterol 2014; 20:7534-7543. [PMID: 24976694 PMCID: PMC4069285 DOI: 10.3748/wjg.v20.i24.7534] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 01/21/2014] [Accepted: 03/19/2014] [Indexed: 02/06/2023] Open
Abstract
Extrahepatic manifestations (EHMs) of hepatitis C virus (HCV) infection can affect a variety of organ systems with significant morbidity and mortality. Some of the most frequently reported EHM of HCV infection, involve the oral region predominantly or exclusively. Oral lichen planus (OLP) is a chronic inflammatory condition that is potentially malignant and represents cell-mediated reaction to a variety of extrinsic antigens, altered self-antigens, or super antigens. Robust epidemiological evidence support the link between OLP and HCV. As the virus may replicate in the oral mucosa and attract HCV-specific T lymphocytes, HCV may be implicated in OLP pathogenesis. Sjögren syndrome (SjS) is an autoimmune exocrinopathy, characterized by dryness of the mouth and eyes and a multitude of other systemic signs and symptoms. SjS patients have also an increased risk of non-Hodgkin lymphoma. Patients with chronic hepatitis C do frequently have histological signs of Sjögren-like sialadenitis with mild or even absent clinical symptoms. However, it is still unclear if HCV may cause a disease mimicking SjS or it is directly responsible for the development of SjS in a specific subset of patients. Oral squamous cell carcinoma is the most common oral malignant tumour and at least in some part of the world could be linked to HCV.
Collapse
|
6
|
The acyclic retinoid Peretinoin inhibits hepatitis C virus replication and infectious virus release in vitro. Sci Rep 2014; 4:4688. [PMID: 24732793 PMCID: PMC3986704 DOI: 10.1038/srep04688] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/27/2014] [Indexed: 12/21/2022] Open
Abstract
Clinical studies suggest that the oral acyclic retinoid Peretinoin may reduce the recurrence of hepatocellular carcinoma (HCC) following surgical ablation of primary tumours. Since hepatitis C virus (HCV) infection is a major cause of HCC, we assessed whether Peretinoin and other retinoids have any effect on HCV infection. For this purpose, we measured the effects of several retinoids on the replication of genotype 1a, 1b, and 2a HCV in vitro. Peretinoin inhibited RNA replication for all genotypes and showed the strongest antiviral effect among the retinoids tested. Furthermore, it reduced infectious virus release by 80-90% without affecting virus assembly. These effects could be due to reduced signalling from lipid droplets, triglyceride abundance, and the expression of mature sterol regulatory element-binding protein 1c and fatty acid synthase. These negative effects of Peretinoin on HCV infection may be beneficial in addition to its potential for HCC chemoprevention in HCV-infected patients.
Collapse
|
7
|
Wang Q, Liu Y, An D, Diao H, Xu W, He X, Sun R, Wei L, Li L. Regulation of hepatitis C virus translation initiation by iron: role of eIF3 and La protein. Virus Res 2012; 167:302-9. [PMID: 22634302 DOI: 10.1016/j.virusres.2012.05.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/16/2012] [Accepted: 05/17/2012] [Indexed: 12/18/2022]
Abstract
Eukaryotic initiation factors (eIFs) are required for encoding polyprotein of hepatitis C virus (HCV) which is mediated by an internal ribosome-entry site (IRES). Iron overload, a common finding among HCV patients, may be correlated with HCV pathology, but the underlying molecular mechanisms are poorly understood. In this study, we investigated the possible relationship among iron status, eIFs and HCV IRES-mediated translation in vitro. Using bicistronic reporter gene constructs carrying HCV IRES sequence, we found that the levels of intracellular iron were positively associated with the HCV IRES-dependent translation initiation in Huh-7 cells. RT-PCR method showed that iron treatment specifically increased the levels of eIF3A mRNA and La mRNA, whereas iron chelation reduced them. Western blots also confirmed that iron-dependent changes in eIF3A mRNA and La mRNA affected the expression of their proteins. Moreover, antisense phosphorothioate oligodeoxynucleotides to eIF3A and La successfully suppressed the levels of eIF3A and La protein and significantly reduced iron-dependent HCV translation. Taken together, our results suggest that iron promotes the translation initiation of HCV by stimulating the expression of eIF3A and La proteins. Inhibition of eIF3A and La proteins substantially repressed iron-dependent HCV translation, a beneficial effect that may have significant clinical implications.
Collapse
Affiliation(s)
- Qiang Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou 310003, China
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Liu Y, An D, Sun R, Jin L, Wang Q. Inhibition of translation initiation factors might be the potential therapeutic targets for HCV patients with hepatic iron overload. Med Hypotheses 2011; 78:142-3. [PMID: 22047986 DOI: 10.1016/j.mehy.2011.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 10/11/2011] [Indexed: 12/21/2022]
Abstract
Standard therapy, interferon-alpha (IFN-α) and ribavirin, remains the only available option for treatment of patients with hepatitis C virus (HCV) infection. However, iron overload, a common finding among HCV patients, have a poor response to treatment with current therapy. These data suggest that both host and viral factors are involved in the determination of the outcome of the therapy. Currently, novel antiviral compounds focus on the development of indirect antiviral drugs. The process of the viral translation is considered as the potential therapeutic targets. Coincidentally, study has found that hepatic iron load enhances the levels of eukaryotic initiation factor 3 (eIF3), which is essential for HCV translation. Reversely, iron chelation could reduce eIF3 p170 translation. Our hypothesis is that iron overload may specifically enhance cellular eIFs. As a result, the cellular mechanisms, in patients with iron overload, are utilized for translating viral mRNA into protein. Thus, treatment strategies that target eIFs should be an exceptionally good candidate therapeutic method for HCV patients with hepatic iron overload.
Collapse
Affiliation(s)
- Yiping Liu
- Center of Hygiene Assessment, Institute of Disease Prevention and Control, Academy of Military Medical Sciences, Beijing 100071, China.
| | | | | | | | | |
Collapse
|
9
|
Van Der Kelen K, Beyaert R, Inzé D, De Veylder L. Translational control of eukaryotic gene expression. Crit Rev Biochem Mol Biol 2009; 44:143-68. [PMID: 19604130 DOI: 10.1080/10409230902882090] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Translational control mechanisms are, besides transcriptional control and mRNA stability, the most determining for final protein levels. A large number of accessory factors that assist the ribosome during initiation, elongation, and termination of translation are required for protein synthesis. Cap-dependent translational control occurs mainly during the initiation step, involving eukaryotic initiation factors (eIFs) and accessory proteins. Initiation is affected by various stimuli that influence the phosphorylation status of both eIF4E and eIF2 and through binding of 4E-binding proteins to eIF4E, which finally inhibits cap- dependent translation. Under conditions where cap-dependent translation is hampered, translation of transcripts containing an internal ribosome entry site can still be supported in a cap-independent manner. An interesting example of translational control is the switch between cap-independent and cap-dependent translation during the eukaryotic cell cycle. At the G1-to-S transition, translation occurs predominantly in a cap-dependent manner, while during the G2-to-M transition, cap-dependent translation is inhibited and transcripts are predominantly translated through a cap-independent mechanism.
Collapse
|
10
|
Ouellet DL, Plante I, Boissonneault V, Ayari C, Provost P. Refractoriness of hepatitis C virus internal ribosome entry site to processing by Dicer in vivo. J Negat Results Biomed 2009; 8:8. [PMID: 19678941 PMCID: PMC2746800 DOI: 10.1186/1477-5751-8-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 08/13/2009] [Indexed: 12/16/2022] Open
Abstract
Background Hepatitis C virus (HCV) is a positive-strand RNA virus harboring a highly structured internal ribosome entry site (IRES) in the 5' nontranslated region of its genome. Important for initiating translation of viral RNAs into proteins, the HCV IRES is composed of RNA structures reminiscent of microRNA precursors that may be targeted by the host RNA silencing machinery. Results We report that HCV IRES can be recognized and processed into small RNAs by the human ribonuclease Dicer in vitro. Furthermore, we identify domains II, III and VI of HCV IRES as potential substrates for Dicer in vitro. However, maintenance of the functional integrity of the HCV IRES in response to Dicer overexpression suggests that the structure of the HCV IRES abrogates its processing by Dicer in vivo. Conclusion Our results suggest that the HCV IRES may have evolved to adopt a structure or a cellular context that is refractory to Dicer processing, which may contribute to viral escape of the host RNA silencing machinery.
Collapse
Affiliation(s)
- Dominique L Ouellet
- Centre de Recherche en Rhumatologie et Immunologie, CHUL Research Center/CHUQ, 2705 Blvd Laurier, Quebec, QC, G1V 4G2, Canada.
| | | | | | | | | |
Collapse
|
11
|
Carrozzo M. Oral diseases associated with hepatitis C virus infection. Part 1. sialadenitis and salivary glands lymphoma. Oral Dis 2008; 14:123-30. [PMID: 18208477 DOI: 10.1111/j.1601-0825.2007.01436.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Morbidity associated with hepatitis C virus (HCV) infection is due not only to the sequelae of chronic liver disease, but also to a variety of extraheaptic manifestations (EHM). Some of the most frequently reported EHM of HCV infection involves the oral region predominantly or exclusively and they are the topics of this 2-part review. The current part 1 discusses the evidences on the association of salivary glands disorders with HCV. HCV- infected patients may frequently have histological signs of Sjögren-like sialadenitis with mild or even absent clinical symptoms. However, the pathogenetic role of HCV in Sjogren Syndrome (SS) development and the characteristics distinguishing classic SS from HCV-related sialadenitis are still an issue. It is unclear if the virus may cause a disease mimicking primary SS or if HCV is directly responsible for the development of SS in a specific subset of patients. Notably, some patients may present a triple association between HCV, SS-like sialadenitis and salivary gland lymphoma and the virus may be involved in the lymphomagenesis. The risk of having a salivary gland lymphoma is particularly high in patients with mixed cryoglobulinemia. Little attention has been paid to the effects of anti-HCV treatment on sialadenitis or lymphoma development.
Collapse
Affiliation(s)
- M Carrozzo
- Department of Oral Medicine, School of Dental Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
| |
Collapse
|
12
|
Magyari L, Bene J, Komlósi K, Talián G, Faragó B, Csöngei V, Járomi L, Sáfrány E, Sipeky C, Lakner L, Varga M, Gasztonyi B, Melegh B. Prevalence of SLC22A4 1672T and SLC22A5 −207C combination defined TC haplotype in Hungarian ulcerative colitis patients. Pathol Oncol Res 2007; 13:53-6. [PMID: 17387389 DOI: 10.1007/bf02893441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 12/15/2006] [Indexed: 02/07/2023]
Abstract
Ulcerative colitis (UC) is a chronic inflammatory disease of the gastrointestinal tract. The aim of this study was to verify the prevalence rate of the haplotype called TC, determined by combination of two functional alleles of OCTN cation transporter genes (SLC22A4 1672T and SLC22A5 -207C combination variants) in ulcerative colitis patients and unrelated healthy controls. The "TC haplotype" has recently been suggested to confer risk for UC. A total of 121 unrelated Hungarian subjects with UC and 110 matched controls were genotyped for the two single nucleotide polymorphisms. The genotypes were determined by using PCR/RFLP assay and direct sequencing. The SLC22A4 1672T allele frequency was 46.7% in the patients with UC and 46.4% in the controls, whereas the SLC22A5 -207C allele occurred in 48.8% of the patients and 51.4% of the controls. The prevalence of the TC haplotype was 19% in the patient group and 22.7% in controls. Since there was no accumulation of the TC haplotype in the patient group, our observation suggests that carrying the TC haplotype is not associated with a higher risk for UC in the Hungarian population.
Collapse
Affiliation(s)
- Lili Magyari
- Department of Medical Genetics and Child Development, University of Pécs, Pécs, H-7624, Hungary
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Windisch MP, Frese M, Kaul A, Trippler M, Lohmann V, Bartenschlager R. Dissecting the interferon-induced inhibition of hepatitis C virus replication by using a novel host cell line. J Virol 2005; 79:13778-93. [PMID: 16227297 PMCID: PMC1262607 DOI: 10.1128/jvi.79.21.13778-13793.2005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Hepatitis C virus (HCV), a member of the family Flaviviridae, is a major cause of chronic liver disease. Patients are currently treated with alpha interferon (IFN-alpha) that is given alone or in combination with ribavirin. Unfortunately, this treatment is ineffective in eliminating the virus in a large proportion of individuals. IFN-induced antiviral activities have been intensively studied in the HCV replicon system. It was found that both IFN-alpha and IFN-gamma inhibit HCV replicons, but the underlying mechanisms have not yet been identified. Of note is that nearly all of these studies were performed with the human hepatoma cell line Huh-7. Here, we report that genotypes 1b and 2a replicons also replicate in the human hepatoblastoma cell line HuH6. Similar to what has been described for Huh-7 cells, we observed that efficient HCV replication in HuH6 cells depends on the presence of cell culture-adaptive mutations and the permissiveness of the host cell. However, three major differences exist: in HuH6 cells, viral replication is (i) independent from ongoing cell proliferation, (ii) less sensitive to certain antiviral compounds, and (iii) highly resistant to IFN-gamma. The latter is not due to a general defect in IFN signaling, as IFN-gamma induces the nuclear translocation of signal transducer and activator of transcription 1 (STAT1), the enhanced transcription of several IFN-regulated genes, and the inhibition of unrelated viruses such as influenza A virus and Semliki Forest virus. Taken together, the results establish HuH6 replicon cells as a valuable tool for IFN studies and for the evaluation of antiviral compounds.
Collapse
Affiliation(s)
- Marc P Windisch
- Department of Molecular Virology, Hygiene Institute, University of Heidelberg, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
14
|
Feld JJ, Hoofnagle JH. Mechanism of action of interferon and ribavirin in treatment of hepatitis C. Nature 2005; 436:967-72. [PMID: 16107837 DOI: 10.1038/nature04082] [Citation(s) in RCA: 715] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Since the identification of the hepatitis C virus, great strides have been made in the development of an antiviral therapy. As a crucial mediator of the innate antiviral immune response, interferon-alpha (IFN-alpha) was a natural choice for treatment. Whereas treatment with IFN-alpha alone achieved only modest success, the addition of the broad-spectrum antiviral agent ribavirin greatly improved responses. However, half of the infected individuals with chronic disease do not achieve sustained clearance of hepatitis C virus. To optimize current therapeutic strategies and to develop new therapies, a better understanding of the mechanism of action of IFN and ribavirin will be essential.
Collapse
Affiliation(s)
- Jordan J Feld
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Building 31, Room 9A27, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | |
Collapse
|
15
|
Honda M, Kawai H, Shirota Y, Yamashita T, Kaneko S. Differential gene expression profiles in stage I primary biliary cirrhosis. Am J Gastroenterol 2005; 100:2019-30. [PMID: 16128947 DOI: 10.1111/j.1572-0241.2005.41662.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Primary biliary cirrhosis (PBC) is a progressive disease. However, little is understood about the molecular mechanisms underlying its features. METHODS We analyzed gene expression profiles of liver biopsy samples from 16 patients with PBC, seven with autoimmune hepatitis, eight with chronic hepatitis C, and eight normal control livers. In addition to whole liver samples, we selectively analyzed chronic nonsuppurative destructive cholangitis (CNSDC) lesions by laser capture microdissection. RESULTS Hierarchical clustering analysis using only early-stage liver disease demonstrated 85 genes were upregulated in stage I PBC specifically. Surprisingly, the expression of these genes was not maintained in advanced-stage PBC, while other gene clusters were upregulated. Expression analysis of CNSDC lesions in stage I PBC showed the presence of active inflammatory changes, characterized by the significant elevation of interferon-gamma and the development and maturation of lymphocytes. Expression of these genes was diminished in lymphoid cells aggregation in stage III PBC, and genes reflecting hepatocyte damage were upregulated with disease progression. CONCLUSION Gene expression patterns in stage I PBC are different from others. There are distinct changes in molecular pathology from early- to late-stage PBC, which might be a clue to reveal the etiology and progression of PBC.
Collapse
Affiliation(s)
- Masao Honda
- Department of Gastroenterology, Graduate School of Medicine, Kanazawa University, Kanazawa, Japan
| | | | | | | | | |
Collapse
|