The hepatitis C virus (HCV) NS4B protein is known to induce the formation of a membranous web that is thought to be the site of viral RNA replication. However, the exact functions of NS4B remain poorly characterized. In this study, we found that NS4B induced apoptosis in 293T cells and Huh7 cells, as confirmed by Hoechst staining, DNA fragmentation, and annexin V/PI assays. Furthermore, protein immunoblot analysis demonstrated that NS4B triggered the cleavage of caspase 3, caspase 7, and poly(ADP-ribose) polymerase (PARP). Further studies revealed that NS4B induced the activation of caspase 9, the reduction of mitochondrial membrane potential and the release of cytochrome c from the mitochondria. However, NS4B expression did not trigger XBP1 mRNA splicing and increase the expression of binding immunoglobulin protein (BiP, or GRP78) and C/EBP homologous protein (CHOP), which serves as the indicators of ER stress. Taken together, our results suggest that HCV NS4B induces apoptosis through the mitochondrial death pathway.
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http://dx.doi.org/10.1016/j.virusres.2012.04.006 | DOI Listing |
Front Cell Infect Microbiol
November 2024
Department of Infectious Diseases, The First People's Hospital of Kashi Prefecture, Kashi, China.
Introduction: The hepatitis C virus (HCV) poses a major global health challenge, with its non-structural proteins being essential for viral replication and pathogenesis. Mutations in these proteins significantly contribute to drug resistance, necessitating innovative therapeutic strategies. This study aims to identify epitope-based therapeutic targets in the non-structural proteins of HCV genotype 1, employing in-depth in silico tools to counteract emerging drug resistance.
View Article and Find Full Text PDFAntiviral Res
November 2024
College of Veterinary Medicine and Bio-Safety Research Institute, Jeonbuk National University, Iksan, 54596, Republic of Korea. Electronic address:
Microbiol Spectr
February 2024
Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Lower Saxony, Germany.
Assembly of infectious hepatitis C virus (HCV) particles requires multiple cellular proteins including for instance apolipoprotein E (ApoE). To describe these protein-protein interactions, we performed an affinity purification mass spectrometry screen of HCV-infected cells. We used functional viral constructs with epitope-tagged envelope protein 2 (E2), protein (p) 7, or nonstructural protein 4B (NS4B) as well as cells expressing a tagged variant of ApoE.
View Article and Find Full Text PDFArch Virol
March 2023
Department of Laboratory Science, First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510600, China.
Hepatitis C virus (HCV) infection causes abnormal lipid metabolism in hepatocytes, which leads to hepatic steatosis and even hepatocellular carcinoma. HCV nonstructural protein 4B (NS4B) has been reported to induce lipogenesis, but the underlying mechanism is unclear. In this study, western blots were performed to investigate the effect of NS4B protein levels on key effectors of the Hippo and AKT signaling pathways.
View Article and Find Full Text PDFCancer Prev Res (Phila)
March 2023
Mayo Clinic, Rochester, Minnesota.
Unlabelled: Chronic hepatitis C can lead to cirrhosis and hepatocellular carcinoma. We studied the safety and immunogenicity of a novel therapeutic hepatitis C virus (HCV) genotype 1a/1b consensus DNA vaccine, INO-8000, encoding HCV NS3, NS4A, NS4B, and NS5A proteins alone or co-administered with DNA-encoding IL12 (INO-9012), a human cytokine that stimulates cellular immune function, in individuals with chronic hepatitis C. This was a phase I, multisite dose-escalation trial with an expansion cohort evaluating doses of 0, 0.
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