Inhibition of hepatitis C virus replication by peroxidation of arachidonate and restoration by vitamin E

Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9046, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 11/2007; 104(47):18666-70. DOI: 10.1073/pnas.0708423104
Source: PubMed


Hepatitis C virus (HCV) is a single-stranded positive-sense RNA virus of the Flaviviridae family. HCV-infected hepatocytes are known to produce reactive oxygen species (ROS), which initiate lipid peroxidation, a reaction that converts polyunsaturated fatty acids, such as arachidonate, into reactive carbonyls that inactivate proteins. To study the effect of lipid peroxidation on HCV replication, we administered arachidonate to Huh7 cells that harbor an HCV replicon (Huh7-K2040 cells). After incubation in medium supplemented with arachidonate but deprived of lipid-soluble antioxidants, the cellular amount of malondialdehyde (MDA), a product of lipid peroxidation, increased markedly in Huh7-K2040 cells but not in parental Huh7 cells that do not harbor an HCV replicon. This increase was followed by a sharp reduction (>95%) in HCV RNA. Both of these events were prevented when cells were treated with vitamin E, a lipid-soluble antioxidant. After prolonged incubation of Huh7-K2040 cells with arachidonate in the absence of lipid-soluble antioxidants, the amount of MDA decreased after the reduction in the amount of HCV RNA. Thus, in the presence of arachidonate and in the absence of lipid-soluble antioxidants, HCV replication induces lipid peroxidation that reduces the amount of HCV RNA. Our results provide a mechanism for the previous observation that polyunsaturated fatty acids inhibit HCV replication [Kapadia SB, Chisari FV (2005) Proc Natl Acad Sci USA 102:2561-2566], and they suggest that these agents may be effective in inhibiting HCV replication in vivo.

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Available from: Yan Chen, Nov 06, 2014
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    • "Additionally, administration of EPA allows maintenance of the original ribavirin dose in patients with CH-C during peg-IFN plus ribavirin combination therapy [73]. Using HCV replicon systems, it was reported that statins and EPA have suppressive effects against HCV replication and synergistic antiviral action with IFN [37, 70, 71, 74, 75]. "
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    ABSTRACT: It has been reported that hepatitis C virus (HCV) infection is closely associated with hepatic metabolic disorders. Hepatic steatosis and insulin resistance are both relatively common in patients with chronic hepatitis C. Recent investigations suggest that HCV infection changes the expression profile of lipid-metabolism-associated factors in the liver, conferring advantages to the life cycle of HCV. Moreover, insulin resistance and steatosis are independent predictors of impaired response to antiviral treatment in chronic hepatitis C. In this paper, we summarize our current knowledge of hepatic metabolic disorders and describe how HCV leads to and exploits these hepatic disorders. We also discuss the clinical significance of insulin sensitizers used to improve insulin resistance and lipid modulators used to manage lipid metabolism as potential treatment options for chronic hepatitis C.
    06/2012; 2012(4):264017. DOI:10.1155/2012/264017
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    • "In a series of elegant experiments, Choi et al demonstrated that ROS induced increases in Ca 2+ inhibits viral replication in replicons or in vitro (Choi et al., 2004; Choi et al., 2006). This conclusion is further supported by data showing a direct antiviral effects of lipid peroxidation (Huang et al., 2007), arsenic related oxidative stress (Kuroki et al., 2009), and oxidant-induced ERK activation (Yano et al., 2009). In contrast, other studies have shown that the oxidative stress produced by alcohol metabolism specifically increases viral replication (McCartney et al., 2008) although it is possible that this may be mediated by other aspects of alcohol metabolism. "
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    Alcoholism Clinical and Experimental Research 10/2010; 34(10):1675-86. DOI:10.1111/j.1530-0277.2010.01255.x · 3.21 Impact Factor
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    • "Because transfection with siRNAs can be cytotoxic, especially at high concentrations [17], and consequently will affect viral replication [18], we examined the morphology of transfected cells using phase-contrast light microscopy and followed emergence of any cytopathic signs such as changes in the refractive index or cytoplasmic shrinkage of the cells. Alternatively we used vital dyes, such as Trypan blue. "
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    ABSTRACT: The Orthopoxvirus genus of Poxviridae family is comprised of several human pathogens, including cowpox (CPXV), Vaccinia (VACV), monkeypox (MPV) and Variola (VARV) viruses. Species of this virus genus cause human diseases with various severities and outcome ranging from mild conditions to death in fulminating cases. Currently, vaccination is the only protective measure against infection with these viruses and no licensed antiviral drug therapy is available. In this study, we investigated the potential of RNA interference pathway (RNAi) as a therapeutic approach for orthopox virus infections using MPV as a model. Based on genome-wide expression studies and bioinformatic analysis, we selected 12 viral genes and targeted them by small interference RNA (siRNA). Forty-eight siRNA constructs were developed and evaluated in vitro for their ability to inhibit viral replication. Two genes, each targeted with four different siRNA constructs in one pool, were limiting to viral replication. Seven siRNA constructs from these two pools, targeting either an essential gene for viral replication (A6R) or an important gene in viral entry (E8L), inhibited viral replication in cell culture by 65-95% with no apparent cytotoxicity. Further analysis with wild-type and recombinant MPV expressing green fluorescence protein demonstrated that one of these constructs, siA6-a, was the most potent and inhibited viral replication for up to 7 days at a concentration of 10 nM. These results emphasis the essential role of A6R gene in viral replication, and demonstrate the potential of RNAi as a therapeutic approach for developing oligonucleotide-based drug therapy for MPV and other orthopox viruses.
    Virology Journal 11/2009; 6(1):188. DOI:10.1186/1743-422X-6-188 · 2.18 Impact Factor
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