Hussein Aly | National institute of infectious diseases (original) (raw)

Papers by Hussein Aly

Research paper thumbnail of 1) Serum derived hepatitis C virus infectivity in infterferon regulatory factor-7-suppressed

At this moment, we don't have an efficient in vitro infection system for natural HCV from ser... more At this moment, we don't have an efficient in vitro infection system for natural HCV from sera of patients with hepatitis C. We, therefore, aimed to establish an immortalized hepatocyte cells that could be infected by HCV particles from patients' sera. We transduced primary human hepatocytes with human telomerase reverse transcriptase together with human papilloma virus 18/E6E7 (HPV18/E6E7) genes to immortalize cells. Finally we analyzed HCV infectivity in these established immortalized cells. Even after prolonged culture HPV18/E6E7-immortalized hepatocytes exhibited hepatocyte functions and marker expression and were prone to HCV infection. The susceptibility of HPV18/E6E7-immortalized hepatocytes to infection of HCVs, including those of genotype 1b, and 2a, was further improved, in particular, by impairing signaling through interferon regulatory factor-7. We observed HCV infection and replication in these cells were effectively inhibited by treatments of CsA or NIM811. The...

Research paper thumbnail of The J6JFH1 Strain of Hepatitis C Virus Infects Human B-Cells with Low Replication Efficacy

Viral Immunology, 2014

Abstract Hepatitis C virus (HCV) infection is a serious health problem worldwide that can lead to... more Abstract Hepatitis C virus (HCV) infection is a serious health problem worldwide that can lead to hepatocellular carcinoma or end-stage liver disease. Current treatment with pegylated interferon, ribavirin, and NS3/4A protease inhibitor would lead to a good prognosis in a large population of patients, but there is still no effective vaccine for HCV. HCV robustly infects hepatocytes in the liver. However, extrahepatic manifestations such as mixed cryoglobulinemia, a systemic immune complex-mediated disorder characterized by B-cell proliferation, which may evolve into overt B-cell non-Hodgkin's lymphoma, have been demonstrated. HCV-RNA is often found to be associated with peripheral blood lymphocytes, suggesting a possible interaction with peripheral blood mononuclear cells (PBMCs), especially B-cells with HCV. B-cell HCV infection was a matter of debate for a long time, and the new advance in HCV in vitro infectious systems suggest that exosome can transmit HCV genome to support "infection." We aimed to clarify the susceptibility of primary B-cells to HCV infection, and to study its functional effect. In this article, we found that the recombinant HCV J6JFH1 strain could infect human B-cells isolated from the peripheral blood of normal volunteers by the detection of both HCV-negative-strand RNA by reverse transcription polymerase chain reaction, and NS5A protein. We also show the blocking of HCV replication by type I interferon after B-cell HCV infection. Although HCV replication in B-lymphocytes showed lower efficiency, in comparison with hepatocyte line (Huh7) cells, our results clearly demonstrate that human B-lymphocytes without other non-B-cells can actually be infected with HCV, and that this interaction leads to the induction of B-cells' innate immune response, and change the response of these cells to apoptosis.

Research paper thumbnail of Cell Type-Specific Subcellular Localization of Phospho-TBK1 in Response to Cytoplasmic Viral DNA

PLoS ONE, 2013

Cytoplasmic viral RNA and DNA are recognized by RIG-I-like receptors and DNA sensors that include... more Cytoplasmic viral RNA and DNA are recognized by RIG-I-like receptors and DNA sensors that include DAI, IFI16, DDX41, and cGAS. The RNA and DNA sensors evoke innate immune responses through the IPS-1 and STING adaptors. IPS-1 and STING activate TBK1 kinase. TBK1 is phosphorylated in its activation loop, leading to IRF3/7 activation and Type I interferon (IFN) production. IPS-1 and STING localize to the mitochondria and endoplasmic reticulum, respectively, whereas it is unclear where phosphorylated TBK1 is localized in response to cytoplasmic viral DNA. Here, we investigated phospho-TBK1 (p-TBK1) subcellular localization using a p-TBK1-specific antibody. Stimulation with vertebrate DNA by transfection increased p-TBK1 levels. Interestingly, stimulation-induced p-TBK1 exhibited mitochondrial localization in HeLa and HepG2 cells and colocalized with mitochondrial IPS-1 and MFN-1. Hepatitis B virus DNA stimulation or herpes simplex virus type-1 infection also induced p-TBK1 mitochondrial localization in HeLa cells, indicating that cytoplasmic viral DNA induces p-TBK1 mitochondrial localization in HeLa cells. In contrast, p-TBK1 did not show mitochondrial localization in RAW264.7, L929, or T-23 cells, and most of p-TBK1 colocalized with STING in response to cytoplasmic DNA in those mammalian cells, indicating cell type-specific localization of p-TBK1 in response to cytoplasmic viral DNA. A previous knockout study showed that mouse IPS-1 was dispensable for Type I IFN production in response to cytoplasmic DNA. However, we found that knockdown of IPS-1 markedly reduced p-TBK1 levels in HeLa cells. Taken together, our data elucidated the cell type-specific subcellular localization of p-TBK1 and a cell type-specific role of IPS-1 in TBK1 activation in response to cytoplasmic viral DNA. Citation: Suzuki T, Oshiumi H, Miyashita M, Aly HH, Matsumoto M, et al. (2013) Cell Type-Specific Subcellular Localization of Phospho-TBK1 in Response to Cytoplasmic Viral DNA. PLoS ONE 8(12): e83639.

Research paper thumbnail of Development of Mouse Hepatocyte Lines Permissive for Hepatitis C Virus (HCV)

PLoS ONE, 2011

The lack of a suitable small animal model for the analysis of hepatitis C virus (HCV) infection h... more The lack of a suitable small animal model for the analysis of hepatitis C virus (HCV) infection has hampered elucidation of the HCV life cycle and the development of both protective and therapeutic strategies against HCV infection. Human and mouse harbor a comparable system for antiviral type I interferon (IFN) induction and amplification, which regulates viral infection and replication. Using hepatocytes from knockout (ko) mice, we determined the critical step of the IFN-inducing/ amplification pathways regulating HCV replication in mouse. The results infer that interferon-beta promoter stimulator (IPS-1) or interferon A receptor (IFNAR) were a crucial barrier to HCV replication in mouse hepatocytes. Although both IFNARko and IPS-1ko hepatocytes showed a reduced induction of type I interferons in response to viral infection, only IPS-1-/-cells circumvented cell death from HCV cytopathic effect and significantly improved J6JFH1 replication, suggesting IPS-1 to be a key player regulating HCV replication in mouse hepatocytes. We then established mouse hepatocyte lines lacking IPS-1 or IFNAR through immortalization with SV40T antigen. Expression of human (h)CD81 on these hepatocyte lines rendered both lines HCVcc-permissive. We also found that the chimeric J6JFH1 construct, having the structure region from J6 isolate enhanced HCV replication in mouse hepatocytes rather than the full length original JFH1 construct, a new finding that suggests the possible role of the HCV structural region in HCV replication. This is the first report on the entry and replication of HCV infectious particles in mouse hepatocytes. These mouse hepatocyte lines will facilitate establishing a mouse HCV infection model with multifarious applications.

Research paper thumbnail of In vitro models for analysis of the hepatitis C virus life cycle

Microbiology and Immunology, 2012

approximately 170 million people worldwide. HCV infection is a major global health problem as it ... more approximately 170 million people worldwide. HCV infection is a major global health problem as it can be complicated with liver cirrhosis and hepatocellular carcinoma. So far, there is no vaccine available and the non-specific, interferon (IFN)-based treatments now in use have significant side-effects and are frequently ineffective, as only approximately 50% of treated patients with genotypes 1 and 4 demonstrate HCV clearance. The lack of suitable in vitro and in vivo models for the analysis of HCV infection has hampered elucidation of the HCV life cycle and the development of both protective and therapeutic strategies against HCV infection. The present review focuses on the progress made towards the establishment of such models.

Research paper thumbnail of Serum-derived hepatitis C virus infectivity in interferon regulatory factor-7-suppressed human primary hepatocytes

Journal of Hepatology, 2007

Background/Aims: The development of an efficient in vitro infection system for HCV is important i... more Background/Aims: The development of an efficient in vitro infection system for HCV is important in order to develop new anti-HCV strategy. Only Huh7 hepatocyte cell lines were shown to be infected with JFH-1 fulminant HCV-2a strain and its chimeras. Here we aimed to establish a primary hepatocyte cell line that could be infected by HCV particles from patients' sera.

Research paper thumbnail of Regulation of the hepatitis C virus genome replication by miR-199a

Journal of Hepatology, 2009

Background/Aims: Hepatitis C virus (HCV) infection causes chronic hepatitis and hepatocellular ca... more Background/Aims: Hepatitis C virus (HCV) infection causes chronic hepatitis and hepatocellular carcinoma. Current anti-HCV therapies are based on interferon therapy, which is insufficiently effective. microRNAs (miRNAs) are non-coding RNAs that regulate gene expression, and they have recently been shown to play an important role in viral replication.

Research paper thumbnail of Strain-dependent viral dynamics and virus-cell interactions in a novel in vitro system supporting the life cycle of blood-borne hepatitis C virus

Hepatology, 2009

We developed an in vitro system that can be used for the study of the life cycle of a wide variet... more We developed an in vitro system that can be used for the study of the life cycle of a wide variety of blood-borne hepatitis C viruses (HCV) from various patients using a threedimensional hollow fiber culture system and an immortalized primary human hepatocyte (HuS-E/2) cell line. Unlike the conventional two-dimensional culture, this system not only enhanced the infectivity of blood-borne HCV but also supported its long-term proliferation and the production of infectious virus particles. Both sucrose gradient fractionation and electron microscopy examination showed that the produced virus-like particles are within a similar fraction and size range to those previously reported. Infection with different HCV strains showed strain-dependent different patterns of HCV proliferation and particle production. Fluctuation of virus proliferation and particle production was found during prolonged culture and was found to be associated with change in the major replicating virus strain. Induction of cellular apoptosis was only found when strains of HCV-2a genotype were used for infection. Interferon-alpha stimulation also varied among different strains of HCV-1b genotypes tested in this study. Conclusion: These results suggest that this in vitro infection system can reproduce strain-dependent events reflecting viral dynamics and viruscell interactions at the early phase of blood-borne HCV infection, and that this system can allow the development of new anti-HCV strategies specific to various HCV strains.

Research paper thumbnail of Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP

Biochemical and Biophysical Research Communications, 2014

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / y b b r c Please ... more j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / y b b r c Please cite this article in press as: M. Iwamoto et al., Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP, Biochem. Biophys. Res. Commun. (2013), http://dx.Please cite this article in press as: M. Iwamoto et al., Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP, Biochem. Biophys. Res. Commun. (2013), http://dx.

Research paper thumbnail of 3D cultured immortalized human hepatocytes useful to develop drugs for blood-borne HCV

Biochemical and Biophysical Research Communications, 2009

Due to the high polymorphism of natural hepatitis C virus (HCV) variants, existing recombinant HC... more Due to the high polymorphism of natural hepatitis C virus (HCV) variants, existing recombinant HCV replication models have failed to be effective in developing effective anti-HCV agents. In the current study, we describe an in vitro system that supports the infection and replication of natural HCV from patient blood using an immortalized primary human hepatocyte cell line cultured in a three-dimensional (3D) culture system. Comparison of the gene expression profile of cells cultured in the 3D system to those cultured in the existing 2D system demonstrated an up-regulation of several genes activated by peroxisome proliferator-activated receptor alpha (PPARa) signaling. Furthermore, using PPARa agonists and antagonists, we also analyzed the effect of PPARa signaling on the modulation of HCV replication using this system. The 3D in vitro system described in this study provides significant insight into the search for novel anti-HCV strategies that are specific to various strains of HCV.

Research paper thumbnail of Multi-Step Regulation of Interferon Induction by Hepatitis C Virus

Archivum Immunologiae et Therapiae Experimentalis, 2013

Acute hepatitis C virus (HCV) infection evokes several distinct innate immune responses in host, ... more Acute hepatitis C virus (HCV) infection evokes several distinct innate immune responses in host, but the virus usually propagates by circumventing these responses. Although a replication intermediate double-stranded RNA is produced in infected cells, type I interferon (IFN) induction and immediate cell death are largely blocked in infected cells. In vitro studies suggested that type I and III IFNs are mainly produced in HCV-infected hepatocytes if the MAVS pathway is functional, and dysfunction of this pathway may lead to cellular permissiveness to HCV replication and production. Cellular immunity, including natural killer cell activation and antigen-specific CD8 T-cell proliferation, occurs following innate immune activation in response to HCV, but is often ineffective for eradication of HCV. Constitutive dsRNA stimulation differs in output from type I IFN therapy, which has been an authentic therapy for patients with HCV. Host innate immune responses to HCV RNA/proteins may be associated with progressive hepatic fibrosis and carcinogenesis once persistent HCV infection is established in opposition to the IFN system. Hence, innate RNA sensing exerts pivotal functions against HCV genome replication and host pathogenesis through modulation of the IFN system. Molecules participating in the RIG-I and Toll-like receptor 3 pathways are the main targets for HCV, disabling the anti-viral functions of these IFN-inducing molecules. We discuss the mechanisms that abolish type I and type III IFN production in HCV-infected cells, which may contribute to understanding the mechanism of virus persistence and resistance to the IFN therapy.

Research paper thumbnail of 1) Serum derived hepatitis C virus infectivity in infterferon regulatory factor-7-suppressed

At this moment, we don't have an efficient in vitro infection system for natural HCV from ser... more At this moment, we don't have an efficient in vitro infection system for natural HCV from sera of patients with hepatitis C. We, therefore, aimed to establish an immortalized hepatocyte cells that could be infected by HCV particles from patients' sera. We transduced primary human hepatocytes with human telomerase reverse transcriptase together with human papilloma virus 18/E6E7 (HPV18/E6E7) genes to immortalize cells. Finally we analyzed HCV infectivity in these established immortalized cells. Even after prolonged culture HPV18/E6E7-immortalized hepatocytes exhibited hepatocyte functions and marker expression and were prone to HCV infection. The susceptibility of HPV18/E6E7-immortalized hepatocytes to infection of HCVs, including those of genotype 1b, and 2a, was further improved, in particular, by impairing signaling through interferon regulatory factor-7. We observed HCV infection and replication in these cells were effectively inhibited by treatments of CsA or NIM811. The...

Research paper thumbnail of The J6JFH1 Strain of Hepatitis C Virus Infects Human B-Cells with Low Replication Efficacy

Viral Immunology, 2014

Abstract Hepatitis C virus (HCV) infection is a serious health problem worldwide that can lead to... more Abstract Hepatitis C virus (HCV) infection is a serious health problem worldwide that can lead to hepatocellular carcinoma or end-stage liver disease. Current treatment with pegylated interferon, ribavirin, and NS3/4A protease inhibitor would lead to a good prognosis in a large population of patients, but there is still no effective vaccine for HCV. HCV robustly infects hepatocytes in the liver. However, extrahepatic manifestations such as mixed cryoglobulinemia, a systemic immune complex-mediated disorder characterized by B-cell proliferation, which may evolve into overt B-cell non-Hodgkin's lymphoma, have been demonstrated. HCV-RNA is often found to be associated with peripheral blood lymphocytes, suggesting a possible interaction with peripheral blood mononuclear cells (PBMCs), especially B-cells with HCV. B-cell HCV infection was a matter of debate for a long time, and the new advance in HCV in vitro infectious systems suggest that exosome can transmit HCV genome to support "infection." We aimed to clarify the susceptibility of primary B-cells to HCV infection, and to study its functional effect. In this article, we found that the recombinant HCV J6JFH1 strain could infect human B-cells isolated from the peripheral blood of normal volunteers by the detection of both HCV-negative-strand RNA by reverse transcription polymerase chain reaction, and NS5A protein. We also show the blocking of HCV replication by type I interferon after B-cell HCV infection. Although HCV replication in B-lymphocytes showed lower efficiency, in comparison with hepatocyte line (Huh7) cells, our results clearly demonstrate that human B-lymphocytes without other non-B-cells can actually be infected with HCV, and that this interaction leads to the induction of B-cells' innate immune response, and change the response of these cells to apoptosis.

Research paper thumbnail of Cell Type-Specific Subcellular Localization of Phospho-TBK1 in Response to Cytoplasmic Viral DNA

PLoS ONE, 2013

Cytoplasmic viral RNA and DNA are recognized by RIG-I-like receptors and DNA sensors that include... more Cytoplasmic viral RNA and DNA are recognized by RIG-I-like receptors and DNA sensors that include DAI, IFI16, DDX41, and cGAS. The RNA and DNA sensors evoke innate immune responses through the IPS-1 and STING adaptors. IPS-1 and STING activate TBK1 kinase. TBK1 is phosphorylated in its activation loop, leading to IRF3/7 activation and Type I interferon (IFN) production. IPS-1 and STING localize to the mitochondria and endoplasmic reticulum, respectively, whereas it is unclear where phosphorylated TBK1 is localized in response to cytoplasmic viral DNA. Here, we investigated phospho-TBK1 (p-TBK1) subcellular localization using a p-TBK1-specific antibody. Stimulation with vertebrate DNA by transfection increased p-TBK1 levels. Interestingly, stimulation-induced p-TBK1 exhibited mitochondrial localization in HeLa and HepG2 cells and colocalized with mitochondrial IPS-1 and MFN-1. Hepatitis B virus DNA stimulation or herpes simplex virus type-1 infection also induced p-TBK1 mitochondrial localization in HeLa cells, indicating that cytoplasmic viral DNA induces p-TBK1 mitochondrial localization in HeLa cells. In contrast, p-TBK1 did not show mitochondrial localization in RAW264.7, L929, or T-23 cells, and most of p-TBK1 colocalized with STING in response to cytoplasmic DNA in those mammalian cells, indicating cell type-specific localization of p-TBK1 in response to cytoplasmic viral DNA. A previous knockout study showed that mouse IPS-1 was dispensable for Type I IFN production in response to cytoplasmic DNA. However, we found that knockdown of IPS-1 markedly reduced p-TBK1 levels in HeLa cells. Taken together, our data elucidated the cell type-specific subcellular localization of p-TBK1 and a cell type-specific role of IPS-1 in TBK1 activation in response to cytoplasmic viral DNA. Citation: Suzuki T, Oshiumi H, Miyashita M, Aly HH, Matsumoto M, et al. (2013) Cell Type-Specific Subcellular Localization of Phospho-TBK1 in Response to Cytoplasmic Viral DNA. PLoS ONE 8(12): e83639.

Research paper thumbnail of Development of Mouse Hepatocyte Lines Permissive for Hepatitis C Virus (HCV)

PLoS ONE, 2011

The lack of a suitable small animal model for the analysis of hepatitis C virus (HCV) infection h... more The lack of a suitable small animal model for the analysis of hepatitis C virus (HCV) infection has hampered elucidation of the HCV life cycle and the development of both protective and therapeutic strategies against HCV infection. Human and mouse harbor a comparable system for antiviral type I interferon (IFN) induction and amplification, which regulates viral infection and replication. Using hepatocytes from knockout (ko) mice, we determined the critical step of the IFN-inducing/ amplification pathways regulating HCV replication in mouse. The results infer that interferon-beta promoter stimulator (IPS-1) or interferon A receptor (IFNAR) were a crucial barrier to HCV replication in mouse hepatocytes. Although both IFNARko and IPS-1ko hepatocytes showed a reduced induction of type I interferons in response to viral infection, only IPS-1-/-cells circumvented cell death from HCV cytopathic effect and significantly improved J6JFH1 replication, suggesting IPS-1 to be a key player regulating HCV replication in mouse hepatocytes. We then established mouse hepatocyte lines lacking IPS-1 or IFNAR through immortalization with SV40T antigen. Expression of human (h)CD81 on these hepatocyte lines rendered both lines HCVcc-permissive. We also found that the chimeric J6JFH1 construct, having the structure region from J6 isolate enhanced HCV replication in mouse hepatocytes rather than the full length original JFH1 construct, a new finding that suggests the possible role of the HCV structural region in HCV replication. This is the first report on the entry and replication of HCV infectious particles in mouse hepatocytes. These mouse hepatocyte lines will facilitate establishing a mouse HCV infection model with multifarious applications.

Research paper thumbnail of In vitro models for analysis of the hepatitis C virus life cycle

Microbiology and Immunology, 2012

approximately 170 million people worldwide. HCV infection is a major global health problem as it ... more approximately 170 million people worldwide. HCV infection is a major global health problem as it can be complicated with liver cirrhosis and hepatocellular carcinoma. So far, there is no vaccine available and the non-specific, interferon (IFN)-based treatments now in use have significant side-effects and are frequently ineffective, as only approximately 50% of treated patients with genotypes 1 and 4 demonstrate HCV clearance. The lack of suitable in vitro and in vivo models for the analysis of HCV infection has hampered elucidation of the HCV life cycle and the development of both protective and therapeutic strategies against HCV infection. The present review focuses on the progress made towards the establishment of such models.

Research paper thumbnail of Serum-derived hepatitis C virus infectivity in interferon regulatory factor-7-suppressed human primary hepatocytes

Journal of Hepatology, 2007

Background/Aims: The development of an efficient in vitro infection system for HCV is important i... more Background/Aims: The development of an efficient in vitro infection system for HCV is important in order to develop new anti-HCV strategy. Only Huh7 hepatocyte cell lines were shown to be infected with JFH-1 fulminant HCV-2a strain and its chimeras. Here we aimed to establish a primary hepatocyte cell line that could be infected by HCV particles from patients' sera.

Research paper thumbnail of Regulation of the hepatitis C virus genome replication by miR-199a

Journal of Hepatology, 2009

Background/Aims: Hepatitis C virus (HCV) infection causes chronic hepatitis and hepatocellular ca... more Background/Aims: Hepatitis C virus (HCV) infection causes chronic hepatitis and hepatocellular carcinoma. Current anti-HCV therapies are based on interferon therapy, which is insufficiently effective. microRNAs (miRNAs) are non-coding RNAs that regulate gene expression, and they have recently been shown to play an important role in viral replication.

Research paper thumbnail of Strain-dependent viral dynamics and virus-cell interactions in a novel in vitro system supporting the life cycle of blood-borne hepatitis C virus

Hepatology, 2009

We developed an in vitro system that can be used for the study of the life cycle of a wide variet... more We developed an in vitro system that can be used for the study of the life cycle of a wide variety of blood-borne hepatitis C viruses (HCV) from various patients using a threedimensional hollow fiber culture system and an immortalized primary human hepatocyte (HuS-E/2) cell line. Unlike the conventional two-dimensional culture, this system not only enhanced the infectivity of blood-borne HCV but also supported its long-term proliferation and the production of infectious virus particles. Both sucrose gradient fractionation and electron microscopy examination showed that the produced virus-like particles are within a similar fraction and size range to those previously reported. Infection with different HCV strains showed strain-dependent different patterns of HCV proliferation and particle production. Fluctuation of virus proliferation and particle production was found during prolonged culture and was found to be associated with change in the major replicating virus strain. Induction of cellular apoptosis was only found when strains of HCV-2a genotype were used for infection. Interferon-alpha stimulation also varied among different strains of HCV-1b genotypes tested in this study. Conclusion: These results suggest that this in vitro infection system can reproduce strain-dependent events reflecting viral dynamics and viruscell interactions at the early phase of blood-borne HCV infection, and that this system can allow the development of new anti-HCV strategies specific to various HCV strains.

Research paper thumbnail of Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP

Biochemical and Biophysical Research Communications, 2014

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / y b b r c Please ... more j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / y b b r c Please cite this article in press as: M. Iwamoto et al., Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP, Biochem. Biophys. Res. Commun. (2013), http://dx.Please cite this article in press as: M. Iwamoto et al., Evaluation and identification of hepatitis B virus entry inhibitors using HepG2 cells overexpressing a membrane transporter NTCP, Biochem. Biophys. Res. Commun. (2013), http://dx.

Research paper thumbnail of 3D cultured immortalized human hepatocytes useful to develop drugs for blood-borne HCV

Biochemical and Biophysical Research Communications, 2009

Due to the high polymorphism of natural hepatitis C virus (HCV) variants, existing recombinant HC... more Due to the high polymorphism of natural hepatitis C virus (HCV) variants, existing recombinant HCV replication models have failed to be effective in developing effective anti-HCV agents. In the current study, we describe an in vitro system that supports the infection and replication of natural HCV from patient blood using an immortalized primary human hepatocyte cell line cultured in a three-dimensional (3D) culture system. Comparison of the gene expression profile of cells cultured in the 3D system to those cultured in the existing 2D system demonstrated an up-regulation of several genes activated by peroxisome proliferator-activated receptor alpha (PPARa) signaling. Furthermore, using PPARa agonists and antagonists, we also analyzed the effect of PPARa signaling on the modulation of HCV replication using this system. The 3D in vitro system described in this study provides significant insight into the search for novel anti-HCV strategies that are specific to various strains of HCV.

Research paper thumbnail of Multi-Step Regulation of Interferon Induction by Hepatitis C Virus

Archivum Immunologiae et Therapiae Experimentalis, 2013

Acute hepatitis C virus (HCV) infection evokes several distinct innate immune responses in host, ... more Acute hepatitis C virus (HCV) infection evokes several distinct innate immune responses in host, but the virus usually propagates by circumventing these responses. Although a replication intermediate double-stranded RNA is produced in infected cells, type I interferon (IFN) induction and immediate cell death are largely blocked in infected cells. In vitro studies suggested that type I and III IFNs are mainly produced in HCV-infected hepatocytes if the MAVS pathway is functional, and dysfunction of this pathway may lead to cellular permissiveness to HCV replication and production. Cellular immunity, including natural killer cell activation and antigen-specific CD8 T-cell proliferation, occurs following innate immune activation in response to HCV, but is often ineffective for eradication of HCV. Constitutive dsRNA stimulation differs in output from type I IFN therapy, which has been an authentic therapy for patients with HCV. Host innate immune responses to HCV RNA/proteins may be associated with progressive hepatic fibrosis and carcinogenesis once persistent HCV infection is established in opposition to the IFN system. Hence, innate RNA sensing exerts pivotal functions against HCV genome replication and host pathogenesis through modulation of the IFN system. Molecules participating in the RIG-I and Toll-like receptor 3 pathways are the main targets for HCV, disabling the anti-viral functions of these IFN-inducing molecules. We discuss the mechanisms that abolish type I and type III IFN production in HCV-infected cells, which may contribute to understanding the mechanism of virus persistence and resistance to the IFN therapy.