Role of apoptotic hepatocytes in HCV dissemination: regulation by acetaldehyde

Alcohol consumption exacerbates hepatitis C virus (HCV) pathogenesis and promotes disease progression, although the mechanisms are not quite clear. We have previously observed that acetaldehyde (Ach) continuously produced by the acetaldehyde-generating system (AGS), temporarily enhanced HCV RNA levels, followed by a decrease to normal or lower levels, which corresponded to apoptosis induction. Here, we studied whether Ach-induced apoptosis caused depletion of HCV-infected cells and what role apoptotic bodies (AB) play in HCV-alcohol crosstalk. In liver cells exposed to AGS, we observed the induction of miR-122 and miR-34a. As miR-34a has been associated with apoptotic signaling and miR-122 with HCV replication, these findings may suggest that cells with intensive viral replication undergo apoptosis. Furthermore, when AGS-induced apoptosis was blocked by a pan-caspase inhibitor, the expression of HCV RNA was not changed. AB from HCV-infected cells contained HCV core protein and the assembled HCV particle that infect intact hepatocytes, thereby promoting the spread of infection. In addition, AB are captured by macrophages to switch their cytokine profile to the proinflammatory one. Macrophages exposed to HCV+ AB expressed more IL-1β, IL-18, IL-6, and IL-10 mRNAs compared with those exposed to HCV− AB. The generation of AB from AGS-treated HCV-infected cells even enhanced the induction of aforementioned cytokines. We conclude that HCV and alcohol metabolites trigger the formation of AB containing HCV particles. The consequent spread of HCV to neighboring hepatocytes via infected AB, as well as the induction of liver inflammation by AB-mediated macrophage activation potentially exacerbate the HCV infection course by alcohol and worsen disease progression.

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Differential Effects on the Hepatitis C Virus (HCV) Internal Ribosome Entry Site by Vitamin B12 and the HCV Core Protein

Journal of Virology ◽

10.1128/jvi.78.21.12075-12081.2004 ◽

2004 ◽

Vol 78 (21) ◽

pp. 12075-12081 ◽

Cited By ~ 13

Author(s):

Dongsheng Li ◽

William B. Lott ◽

John Martyn ◽

Gholamreza Haqshenas ◽

Eric J. Gowans

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Internal Ribosome Entry Site ◽

Core Protein ◽

Vitamin B ◽

Entry Site ◽

Internal Ribosome Entry ◽

Hcv Core Protein ◽

Hcv Ires

ABSTRACT To investigate the role of the hepatitis C virus internal ribosome entry site (HCV IRES) domain IV in translation initiation and regulation, two chimeric IRES elements were constructed to contain the reciprocal domain IV in the otherwise HCV and classical swine fever virus IRES elements. This permitted an examination of the role of domain IV in the control of HCV translation. A specific inhibitor of the HCV IRES, vitamin B12, was shown to inhibit translation directed by all IRES elements which contained domain IV from the HCV and the GB virus B IRES elements, whereas the HCV core protein could only suppress translation from the wild-type HCV IRES. Thus, the mechanisms of translation inhibition by vitamin B12 and the core protein differ, and they target different regions of the IRES.

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Dengue activates mTORC2 signaling to counteract apoptosis and maximize viral replication

10.1101/2020.09.22.308890 ◽

2020 ◽

Author(s):

Christoph C. Carter ◽

Jean Paul Olivier ◽

Alexis Kaushansky ◽

Fred D. Mast ◽

John D. Aitchison

Keyword(s):

Viral Replication ◽

Cell Survival ◽

Structural Protein ◽

Protein Protein Interaction ◽

Mechanistic Target Of Rapamycin ◽

Promote Cell Survival ◽

Important Regulator ◽

Infected Cells ◽

Induced Apoptosis

ABSTRACTThe mechanistic target of rapamycin (mTOR) functions in at least two distinct complexes: mTORC1, which regulates cellular anabolic-catabolic homeostasis, and mTORC2, which is an important regulator of cell survival and cytoskeletal maintenance. mTORC1 has been implicated in the pathogenesis of flaviviruses including dengue, where it contributes to the establishment of a pro-viral autophagic state. In contrast, the role of mTORC2 in viral pathogenesis is unknown. In this study, we explore the consequences of a physical protein-protein interaction between dengue non-structural protein 5 (NS5) and host cell mTOR proteins during infection. Using shRNA to differentially target mTORC1 and mTORC2 complexes, we show that mTORC2 is required for optimal dengue replication. Furthermore, we show that mTORC2 is activated during viral replication, and that mTORC2 counteracts virus-induced apoptosis, promoting the survival of infected cells. This work reveals a novel mechanism by which the dengue flavivirus can promote cell survival to maximize viral replication.

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Cytokine-Modulated Natural Killer Cells Differentially Regulate the Activity of the Hepatitis C Virus

International Journal of Molecular Sciences ◽

10.3390/ijms19092771 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2771 ◽

Cited By ~ 1

Author(s):

Yoo Cho ◽

Hwan Lee ◽

Hyojeung Kang ◽

Hyosun Cho

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Nk Cells ◽

Natural Killer ◽

Core Protein ◽

Lymphoid Cells ◽

Hcv Rna ◽

Cell Infection ◽

Hcv Core Protein

HCV genotype 2a strain JFH-1 replicates and produces viral particles efficiently in human hepatocellular carcinoma (huh) 7.5 cells, which provide a stable in vitro cell infection system for the hepatitis C virus (HCVcc system). Natural killer (NK) cells are large lymphoid cells that recognize and kill virus-infected cells. In this study, we investigated the interaction between NK cells and the HCVcc system. IL-10 is a typical immune regulatory cytokine that is produced mostly by NK cells and macrophages. IL-21 is one of the main cytokines that stimulate the activation of NK cells. First, we used anti-IL-10 to neutralize IL-10 in a coculture of NK cells and HCVcc. Anti-IL-10 treatment increased the maturation of NK cells by enhancing the frequency of the CD56+dim population in NK-92 cells. However, with anti-IL-10 treatment of NK cells in coculture with J6/JFH-1-huh 7.5 cells, there was a significant decrease in the expression of STAT1 and STAT5 proteins in NK-92 cells and an increase in the HCV Core and NS3 proteins. In addition, rIL-21 treatment increased the frequency of the CD56+dim population in NK-92 cells, Also, there was a dramatic increase in the expression of STAT1 and STAT5 proteins in rIL-21 pre-stimulated NK cells and a decrease in the expression of HCV Core protein in coculture with J6/JFH-1-huh 7.5 cells. In summary, we found that the functional activation of NK cells can be modulated by anti-IL-10 or rIL-21, which controls the expression of HCV proteins as well as HCV RNA replication.

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Hepatitis C Virus-Induced Rab32 Aggregation and Its Implications for Virion Assembly

Journal of Virology ◽

10.1128/jvi.01662-16 ◽

2016 ◽

Vol 91 (3) ◽

Cited By ~ 4

Author(s):

Tu M. Pham ◽

Si C. Tran ◽

Yun-Sook Lim ◽

Soon B. Hwang

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Membrane Trafficking ◽

Core Protein ◽

Cell Types ◽

Viral Assembly ◽

Intracellular Membrane ◽

Virion Assembly ◽

Hcv Core Protein ◽

Infected Cells

ABSTRACT Hepatitis C virus (HCV) is highly dependent on cellular factors for viral propagation. Using high-throughput next-generation sequencing, we analyzed the host transcriptomic changes and identified 30 candidate genes which were upregulated in cell culture-grown HCV (HCVcc)-infected cells. Of these candidates, we selected Rab32 for further investigation. Rab32 is a small GTPase that regulates a variety of intracellular membrane-trafficking events in various cell types. In this study, we demonstrated that both mRNA and protein levels of Rab32 were increased in HCV-infected cells. Furthermore, we showed that HCV infection converted the predominantly expressed GTP-bound Rab32 to GDP-bound Rab32, contributing to the aggregation of Rab32 and thus making it less sensitive to cellular degradation machinery. In addition, GDP-bound Rab32 selectively interacted with HCV core protein and deposited core protein into the endoplasmic reticulum (ER)-associated Rab32-derived aggregated structures in the perinuclear region, which were likely to be viral assembly sites. Using RNA interference technology, we demonstrated that Rab32 was required for the assembly step but not for other stages of the HCV life cycle. Taken together, these data suggest that HCV may modulate Rab32 activity to facilitate virion assembly. IMPORTANCE Rab32, a member of the Ras superfamily of small GTPases, regulates various intracellular membrane-trafficking events in many cell types. In this study, we showed that HCV infection concomitantly increased Rab32 expression at the transcriptional level and altered the balance between GDP- and GTP-bound Rab32 toward production of Rab32-GDP. GDP-bound Rab32 selectively interacted with HCV core protein and enriched core in the ER-associated Rab32-derived aggregated structures that were probably necessary for viral assembly. Indeed, we showed that Rab32 was specifically required for the assembly of HCV. Collectively, our study identifies that Rab32 is a novel host factor essential for HCV particle assembly.

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Role of Bcl-2 Family Members in Caspase-Independent Apoptosis during Chlamydia Infection

Infection and Immunity ◽

10.1128/iai.70.1.55-61.2002 ◽

2002 ◽

Vol 70 (1) ◽

pp. 55-61 ◽

Cited By ~ 65

Author(s):

Jean-Luc Perfettini ◽

John C. Reed ◽

Nicole Israël ◽

Jean-Claude Martinou ◽

Alice Dautry-Varsat ◽

...

Keyword(s):

Caspase 3 ◽

Chlamydia Psittaci ◽

Host Cells ◽

Chlamydia Infection ◽

Caspase Inhibitor ◽

Obligate Intracellular Bacterium ◽

Obligate Intracellular ◽

Infected Cells ◽

Induced Apoptosis

ABSTRACT Infection with an obligate intracellular bacterium, the Chlamydia trachomatis lymphogranuloma venereum (LGV/L2) strain or the guinea pig inclusion conjunctivitis serovar of Chlamydia psittaci, leads to apoptosis of host cells. The apoptosis is not affected by a broad-spectrum caspase inhibitor, and caspase-3 is not activated in infected cells, suggesting that apoptosis mediated by these two strains of Chlamydia is independent of known caspases. Overexpression of the proapoptotic Bcl-2 family member, Bax, was previously shown to induce caspase-independent apoptosis, and we find that Bax is activated and translocates from the cytosol to the mitochondria in C. psittaci-infected cells. C. psittaci-induced apoptosis is inhibited in host cells overexpressing Bax inhibitor-1 and is inhibited through overexpression of Bcl-2, which blocks both caspase-dependent and -independent apoptosis. As Bax and mitochondria are ideally located to sense stress-related metabolic changes emanating from the interior of an infected cell, it is likely that Bax-dependent apoptosis may also be observed in cells infected with other intracellular pathogens.

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Interaction of Hepatitis C Virus Core Protein with Viral Sense RNA and Suppression of Its Translation

Journal of Virology ◽

10.1128/jvi.73.12.9718-9725.1999 ◽

1999 ◽

Vol 73 (12) ◽

pp. 9718-9725 ◽

Cited By ~ 117

Author(s):

Takashi Shimoike ◽

Shigetaka Mimori ◽

Hideki Tani ◽

Yoshiharu Matsuura ◽

Tatsuo Miyamura

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Core Protein ◽

Firefly Luciferase ◽

Encephalomyocarditis Virus ◽

Hcv Rna ◽

Dependent Manner ◽

Genomic Rna ◽

The Core ◽

Hcv Core Protein

ABSTRACT To clarify the binding properties of hepatitis C virus (HCV) core protein and its viral RNA for the encapsidation, morphogenesis, and replication of HCV, the specific interaction of HCV core protein with its genomic RNA synthesized in vitro was examined in an in vivo system. The positive-sense RNA from the 5′ end to nucleotide (nt) 2327, which covers the 5′ untranslated region (5′UTR) and a part of the coding region of HCV structural proteins, interacted with HCV core protein, while no interaction was observed in the same region of negative-sense RNA and in other regions of viral and antiviral sense RNAs. The internal ribosome entry site (IRES) exists around the 5′UTR of HCV; therefore, the interaction of the core protein with this region of HCV RNA suggests that there is some effect on its cap-independent translation. Cells expressing HCV core protein were transfected with reporter RNAs consisting of nt 1 to 709 of HCV RNA (the 5′UTR of HCV and about two-thirds of the core protein coding regions) followed by a firefly luciferase gene (HCV07Luc RNA). The translation of HCV07Luc RNA was suppressed in cells expressing the core protein, whereas no significant suppression was observed in the case of a reporter RNA possessing the IRES of encephalomyocarditis virus followed by a firefly luciferase. This suppression by the core protein occurred in a dose-dependent manner. The expression of the E1 envelope protein of HCV or β-galactosidase did not suppress the translation of both HCV and EMCV reporter RNAs. We then examined the regions that are important for suppression of translation by the core protein and found that the region from nt 1 to 344 was enough to exert this suppression. These results suggest that the HCV core protein interacts with viral genomic RNA at a specific region to form nucleocapsids and regulates the expression of HCV by interacting with the 5′UTR.

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Human Cytomegalovirus miR-UL70-3p Downregulates the H2O2-Induced Apoptosis by Targeting the Modulator of Apoptosis-1 (MOAP1)

International Journal of Molecular Sciences ◽

10.3390/ijms23010018 ◽

2021 ◽

Vol 23 (1) ◽

pp. 18

Author(s):

Abhishek Pandeya ◽

Raj Kumar Khalko ◽

Anup Mishra ◽

Nishant Singh ◽

Sukhveer Singh ◽

...

Keyword(s):

Human Cytomegalovirus ◽

Molecular Mechanisms ◽

Ectopic Expression ◽

Antiviral Responses ◽

Persistent Infections ◽

Innate Immune Mechanism ◽

Infected Cells ◽

Hcmv Replication ◽

Induced Apoptosis

Human Cytomegalovirus (HCMV) is a prototypic beta herpesvirus, causing persistent infections in humans. There are medications that are used to treat the symptoms; however, there is no cure yet. Thus, understanding the molecular mechanisms of HCMV replication and its persistence may reveal new prevention strategies. HCMV evasive strategies on the antiviral responses of the human host largely rely on its significant portion of genome. Numerous studies have highlighted the importance of miRNA-mediated regulation of apoptosis, which is an innate immune mechanism that eradicates virus-infected cells. In this study, we explore the antiapoptotic role of hcmv-miR-UL70-3p in HEK293T cells. We establish that hcmv-miR-UL70-3p targets the proapoptotic gene Modulator of Apoptosis-1 (MOAP1) through interaction with its 3’UTR region of mRNA. The ectopic expression of hcmv-miR-UL70-3p mimic significantly downregulates the H2O2-induced apoptosis through the translational repression of MOAP1. Silencing of MOAP1 through siRNA also inhibits the H2O2-induced apoptosis, which further supports the hcmv-miR-UL70-3p mediated antiapoptotic effect by regulating MOAP1 expression. These results uncover a role for hcmv-miR-UL70-3p and its target MOAP1 in regulating apoptosis.

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HCV RNA and antibody to HCV core protein in Japanese patients with chronic liver disease

Digestive Diseases and Sciences ◽

10.1007/bf01296490 ◽

1992 ◽

Vol 37 (10) ◽

pp. 1483-1488 ◽

Cited By ~ 15

Author(s):

Nobukazu Yuki ◽

Norio Hayashi ◽

Hideki Hagiwara ◽

Tetsuo Takehara ◽

Akinori Kasahara ◽

...

Keyword(s):

Liver Disease ◽

Chronic Liver Disease ◽

Core Protein ◽

Japanese Patients ◽

Chronic Liver ◽

Hcv Rna ◽

Hcv Core Protein

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Dynamic Interaction of Stress Granules, DDX3X, and IKK-α Mediates Multiple Functions in Hepatitis C Virus Infection

Journal of Virology ◽

10.1128/jvi.03197-14 ◽

2015 ◽

Vol 89 (10) ◽

pp. 5462-5477 ◽

Cited By ~ 27

Author(s):

Véronique Pène ◽

Qisheng Li ◽

Catherine Sodroski ◽

Ching-Sheng Hsu ◽

T. Jake Liang

Keyword(s):

Core Protein ◽

Hcv Infection ◽

Nonstructural Proteins ◽

Replication Complex ◽

Multiple Functions ◽

Hcv Core Protein ◽

Close Proximity ◽

Infected Cells ◽

Cytoplasmic Structures ◽

Cellular Compartments

ABSTRACTThe ubiquitous ATP-dependent RNA helicase DDX3X is involved in many cellular functions, including innate immunity, and is a pivotal host factor for hepatitis C virus (HCV) infection. Recently, we showed that DDX3X specifically recognizes the HCV 3′ untranslated region (UTR), leading to the activation of IKK-α and a cascade of lipogenic signaling to facilitate lipid droplet biogenesis and viral assembly (Q. Li, V. Pene, S. Krishnamurthy, H. Cha, and T. J. Liang, Nat Med19:722–729, 2013,http://dx.doi.org/10.1038/nm.3190). The interaction of DDX3X with HCV core protein seems to be dispensable for its proviral role. In this study, through systematic imaging and biochemical and virologic approaches, we identified a dynamic association between DDX3X and various cellular compartments and viral elements mediating multiple functions of DDX3X in productive HCV infection. Upon HCV infection, the HCV 3′UTR interacts with DDX3X and IKK-α, which redistribute to speckle-like cytoplasmic structures shown to be stress granules (SGs). As viral proteins accumulate in infected cells, DDX3X granules together with SG-associated proteins redistribute and colocalize with HCV core protein around lipid droplets (LDs). IKK-α, however, does not relocate to the LD but translocates to the nucleus. In HCV-infected cells, various HCV nonstructural proteins also interact or colocalize with DDX3X in close proximity to SGs and LDs, consistent with the tight juxtaposition of the replication complex and the assembly site at the surface of LDs. Short interfering RNA (siRNA)-mediated silencing of DDX3X and multiple SG components markedly inhibits HCV infection. Our data suggest that DDX3X initiates a multifaceted cellular program involving dynamic associations with HCV RNA and proteins, IKK-α, SG, and LD surfaces for its crucial role in the HCV life cycle.IMPORTANCEDDX3X is a proviral host factor for HCV infection. Recently, we showed that DDX3X binds to the HCV 3′UTR, activating IKK-α and cellular lipogenesis to facilitate viral assembly (Q. Li et al., Nat Med19:722–729, 2013,http://dx.doi.org/10.1038/nm.3190). Here, we report associations of DDX3X with various cellular compartments and viral elements that mediate its multiple functions in the HCV life cycle. Upon infection, the HCV 3′UTR redistributes DDX3X and IKK-α to speckle-like cytoplasmic structures shown to be SGs. Subsequently, interactions between DDX3X, SG, and HCV proteins facilitate the translocation of DDX3X-SG complexes to the LD surface. HCV nonstructural proteins are shown to colocalize with DDX3X in close proximity to SGs and LDs, consistent with the tight juxtaposition of the HCV replication complex and assembly site at the LD surface. Our data demonstrate that DDX3X initiates a multifaceted cellular program involving dynamic associations with HCV elements, IKK-α, SGs, and LDs for its critical role in HCV infection.

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