scholarly journals Targeting Autophagy Augments Berberine-Mediated Cell Death in Human Hepatoma Cells Harboring Hepatitis C Virus RNA

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 908 ◽  
Author(s):  
Chen-Jei Tai ◽  
Alagie Jassey ◽  
Ching-Hsuan Liu ◽  
Cheng-Jeng Tai ◽  
Christopher D. Richardson ◽  
...  

Hepatocellular carcinoma (HCC), including hepatitis C virus (HCV)-induced HCC, is a deadly disease highly refractory to chemotherapy, thus requiring the continuous identification of novel treatment strategies. Berberine (BBR) has been previously reported to inhibit hepatoma cell growth, but the main type of cell death elicited by BBR, and whether the alkaloid can inhibit hepatoma cells carrying HCV genomes, is unclear. Herein, we show that BBR treatment induced a biphasic cell death irrespective of the presence of HCV subgenomic replicon RNA, first triggering apoptosis that then progressed to necrosis between 24 and 48 h post-treatment. Furthermore, BBR treatment potentiated the HCV replicon-induced reactive oxygen species (ROS) production, inhibition of which with an antioxidant attenuated the cell death that was elicited by BBR in these cells. Moreover, BBR dampened the autophagic response in HCV RNA-positive or negative hepatoma cells, and pharmacological inhibition of autophagy conversely augmented the BBR-induced cell death. Finally, BBR inhibited the growth of Huh-7 cells that were persistently infected with the full-length genome HCV particles, and concomitant pharmacological inhibition of autophagy potentiated the killing of these cells by BBR. Our findings suggest that combining BBR with the inhibition of autophagy could be an attractive treatment strategy against HCC, irrespective of the presence of the HCV genome.

2010 ◽  
Vol 30 (10) ◽  
pp. 1490-1504 ◽  
Author(s):  
Nury M. Steuerwald ◽  
Judith C. Parsons ◽  
Kristen Bennett ◽  
Tonya C. Bates ◽  
Herbert L. Bonkovsky

2012 ◽  
Vol 93 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Anna Pasetto ◽  
Lars Frelin ◽  
Anette Brass ◽  
Anila Yasmeen ◽  
Sarene Koh ◽  
...  

Hepatitis C virus (HCV) is a major cause of severe liver disease, and one major contributing factor is thought to involve a dysfunction of virus-specific T-cells. T-cell receptor (TCR) gene therapy with HCV-specific TCRs would increase the number of effector T-cells to promote virus clearance. We therefore took advantage of HLA-A2 transgenic mice to generate multiple TCR candidates against HCV using DNA vaccination followed by generation of stable T-cell–BW (T-BW) tumour hybrid cells. Using this approach, large numbers of non-structural protein 3 (NS3)-specific functional T-BW hybrids can be generated efficiently. These predominantly target the genetically stable HCV genotype 1 NS31073–1081 CTL epitope, frequently associated with clearance of HCV in humans. These T-BW hybrid clones recognized the NS31073 peptide with a high avidity. The hybridoma effectively recognized virus variants and targeted cells with low HLA-A2 expression, which has not been reported previously. Importantly, high-avidity murine TCRs effectively redirected human non-HCV-specific T-lymphocytes to recognize human hepatoma cells with HCV RNA replication driven by a subgenomic HCV replicon. Taken together, TCR candidates with a range of functional avidities, which can be used to study immune recognition of HCV-positive targets, have been generated. This has implications for TCR-related immunotherapy against HCV.


2019 ◽  
Vol 47 (12) ◽  
pp. 6411-6424 ◽  
Author(s):  
You Li ◽  
Li Wang ◽  
Efraín E Rivera-Serrano ◽  
Xian Chen ◽  
Stanley M Lemon

AbstractThe liver-specific microRNA, miR-122, is an essential host factor for replication of the hepatitis C virus (HCV). miR-122 stabilizes the positive-strand HCV RNA genome and promotes its synthesis by binding two sites (S1 and S2) near its 5′ end in association with Ago2. Ago2 is essential for both host factor activities, but whether other host proteins are involved is unknown. Using an unbiased quantitative proteomics screen, we identified the TNRC6 protein paralogs, TNRC6B and TNRC6C, as functionally important but redundant components of the miR-122/Ago2 host factor complex. Doubly depleting TNRC6B and TNRC6C proteins reduced HCV replication in human hepatoma cells, dampening miR-122 stimulation of viral RNA synthesis without reducing the stability or translational activity of the viral RNA. TNRC6B/C were required for optimal miR-122 host factor activity only when S1 was able to bind miR-122, and restricted replication when S1 was mutated and only S2 bound by miR-122. TNRC6B/C preferentially associated with S1, and TNRC6B/C depletion enhanced Ago2 association at S2. Collectively, these data suggest a model in which TNRC6B/C regulate the assembly of miR-122/Ago complexes on HCV RNA, preferentially directing miR-122/Ago2 to S1 while restricting its association with S2, thereby fine-tuning the spatial organization of miR-122/Ago2 complexes on the viral genome.


2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Isaac Ruiz ◽  
Quentin Nevers ◽  
Eva Hernández ◽  
Nazim Ahnou ◽  
Rozenn Brillet ◽  
...  

ABSTRACT The quinoline MK-571 is the most commonly used inhibitor of multidrug resistance protein-1 (MRP-1) but was originally developed as a cysteinyl leukotriene receptor 1 (CysLTR1) antagonist. While studying the modulatory effect of MRP-1 on anti-hepatitis C virus (HCV) direct-acting antiviral (DAA) efficiency, we observed an unexpected anti-HCV effect of compound MK-571 alone. This anti-HCV activity was characterized in Huh7.5 cells stably harboring a subgenomic genotype 1b replicon. A dose-dependent decrease of HCV RNA levels was observed upon MK-571 administration, with a 50% effective concentration (EC50 ± standard deviation) of 9 ± 0.3 μM and a maximum HCV RNA level reduction of approximatively 1 log10. MK-571 also reduced the replication of the HCV full-length J6/JFH1 model in a dose-dependent manner. However, probenecid and apigenin homodimer (APN), two specific inhibitors of MRP-1, had no effect on HCV replication. In contrast, the CysLTR1 antagonist SR2640 increased HCV-subgenomic replicon (SGR) RNA levels in a dose-dependent manner, with a maximum increase of 10-fold. In addition, a combination of natural CysLTR1 agonist (LTD4) or antagonists (zafirlukast, cinalukast, and SR2640) with MK-571 completely reversed its antiviral effect, suggesting its anti-HCV activity is related to CysLTR1 rather to MRP-1 inhibition. In conclusion, we showed that MK-571 inhibits HCV replication in hepatoma cell cultures by acting as a CysLTR1 receptor antagonist, thus unraveling a new host-virus interaction in the HCV life cycle.


PLoS ONE ◽  
2013 ◽  
Vol 8 (4) ◽  
pp. e61089 ◽  
Author(s):  
Tzu-Yue Shiu ◽  
Shih-Ming Huang ◽  
Yu-Lueng Shih ◽  
Heng-Cheng Chu ◽  
Wei-Kuo Chang ◽  
...  

2016 ◽  
Vol 90 (8) ◽  
pp. 4174-4185 ◽  
Author(s):  
Emily M. Lee ◽  
Ali Alsagheir ◽  
Xianfang Wu ◽  
Christy Hammack ◽  
John McLauchlan ◽  
...  

ABSTRACTIndividuals chronically infected with hepatitis C virus (HCV) commonly exhibit hepatic intracellular lipid accumulation, termed steatosis. HCV infection perturbs host lipid metabolism through both cellular and virus-induced mechanisms, with the viral core protein playing an important role in steatosis development. We have recently identified a liver protein, the cell death-inducing DFFA-like effector B (CIDEB), as an HCV entry host dependence factor that is downregulated by HCV infection in a cell culture model. In this study, we investigated the biological significance and molecular mechanism of this downregulation. HCV infection in a mouse model downregulated CIDEB in the liver tissue, and knockout of the CIDEB gene in a hepatoma cell line results in multiple aspects of lipid dysregulation that can contribute to hepatic steatosis, including reduced triglyceride secretion, lower lipidation of very-low-density lipoproteins, and increased lipid droplet (LD) stability. The potential link between CIDEB downregulation and steatosis is further supported by the requirement of the HCV core and its LD localization for CIDEB downregulation, which utilize a proteolytic cleavage event that is independent of the cellular proteasomal degradation of CIDEB.IMPORTANCEOur data demonstrate that HCV infection of human hepatocytesin vitroandin vivoresults in CIDEB downregulation via a proteolytic cleavage event. Reduction of CIDEB protein levels by HCV or gene editing, in turn, leads to multiple aspects of lipid dysregulation, including LD stabilization. Consequently, CIDEB downregulation may contribute to HCV-induced hepatic steatosis.


2012 ◽  
Vol 93 (7) ◽  
pp. 1422-1431 ◽  
Author(s):  
Midori Takeda ◽  
Masanori Ikeda ◽  
Yasuo Ariumi ◽  
Takaji Wakita ◽  
Nobuyuki Kato

A hepatitis C virus (HCV) infection system was developed previously using the HCV JFH-1 strain (genotype 2a) and HuH-7 cells, and this cell culture is so far the only robust production system for HCV. In patients with chronic hepatitis C, the virological effects of pegylated interferon and ribavirin therapy differ depending on the HCV strain and the genetic background of the host. Recently, we reported the hepatoma-derived Li23 cell line, in which the JFH-1 life cycle is reproduced at a level almost equal to that in HuH-7-derived RSc cells. To monitor the HCV life cycle more easily, we here developed JFH-1 reporter-assay systems using both HuH-7- and Li23-derived cell lines. To identify any genetic mutations by long-term cell culture, HCV RNAs in HuH-7 cells were amplified 130 days after infection and subjected to sequence analysis to find adaptive mutation(s) for robust virus replication. We identified two mutations, H2505Q and V2995L, in the NS5B region. V2995L but not H2505Q enhanced JFH-1 RNA replication. However, we found that H2505Q but not V2995L enhanced HCV RNA replication of strain O (genotype 1b). We also selected highly permissive D7 cells by serial subcloning of Li23 cells. The expression levels of claudin-1 and Niemann–Pick C1-like 1 in D7 cells are higher than those in parental Li23 cells. In this study, we developed HCV JFH-1 reporter-assay systems using two distinct hepatoma cell lines, HuH-7 and Li23. The mutations in NS5B resulted in different effects on strains O and JFH-1 HCV RNA replication.


2006 ◽  
Vol 80 (12) ◽  
pp. 6013-6023 ◽  
Author(s):  
Guann-Yi Yu ◽  
Ki-Jeong Lee ◽  
Lu Gao ◽  
Michael M. C. Lai

ABSTRACT Hepatitis C Virus (HCV) NS4B protein induces a specialized membrane structure which may serve as the replication platform for HCV RNA replication. In the present study, we demonstrated that NS4B has lipid modifications (palmitoylation) on two cysteine residues (cysteines 257 and 261) at the C-terminal end. Site-specific mutagenesis of these cysteine residues on individual NS4B proteins and on an HCV subgenomic replicon showed that the lipid modifications, particularly of Cys261, are important for protein-protein interaction in the formation of the HCV RNA replication complex. We further demonstrated that NS4B can undergo polymerization. The main polymerization determinants were mapped in the N-terminal cytosolic domain of NS4B protein; however, the lipid modifications on the C terminus also facilitate the polymerization process. The lipid modification and the polymerization activity could be two properties of NS4B important for its induction of the specialized membrane structure involved in viral RNA replication.


2014 ◽  
Vol 89 (4) ◽  
pp. 2052-2063 ◽  
Author(s):  
Amy L. Cherry ◽  
Caitriona A. Dennis ◽  
Andrew Baron ◽  
Leslie E. Eisele ◽  
Pia A. Thommes ◽  
...  

ABSTRACTThe RNA-dependent RNA polymerase (RdRp) of hepatitis C virus (HCV) is essential for viral genome replication. Crystal structures of the HCV RdRp reveal two C-terminal features, a β-loop and a C-terminal arm, suitably located for involvement in positioning components of the initiation complex. Here we show that these two elements intimately regulate template and nucleotide binding, initiation, and elongation. We constructed a series of β-loop and C-terminal arm mutants, which were used forin vitroanalysis of RdRpde novoinitiation and primer extension activities. All mutants showed a substantial decrease in initiation activities but a marked increase in primer extension activities, indicating an ability to form more stable elongation complexes with long primer-template RNAs. Structural studies of the mutants indicated that these enzyme properties might be attributed to an increased flexibility in the C-terminal features resulting in a more open polymerase cleft, which likely favors the elongation process but hampers the initiation steps. A UTP cocrystal structure of one mutant shows, in contrast to the wild-type protein, several alternate conformations of the substrate, confirming that even subtle changes in the C-terminal arm result in a more loosely organized active site and flexible binding modes of the nucleotide. We used a subgenomic replicon system to assess the effects of the same mutations on viral replication in cells. Even the subtlest mutations either severely impaired or completely abolished the ability of the replicon to replicate, further supporting the concept that the correct positioning of both the β-loop and C-terminal arm plays an essential role during initiation and in HCV replication in general.IMPORTANCEHCV RNA polymerase is a key target for the development of directly acting agents to cure HCV infections, which necessitates a thorough understanding of the functional roles of the various structural features of the RdRp. Here we show that even highly conservative changes, e.g., Tyr→Phe or Asp→Glu, in these seemingly peripheral structural features have profound effects on the initiation and elongation properties of the HCV polymerase.


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