scholarly journals A role for autophagolysosomes in dengue virus 3 production in HepG2 cells

2009 ◽  
Vol 90 (5) ◽  
pp. 1093-1103 ◽  
Author(s):  
Atefeh Khakpoor ◽  
Mingkwan Panyasrivanit ◽  
Nitwara Wikan ◽  
Duncan R. Smith
Keyword(s):  
Life Cycle ◽  
Confocal Microscopy ◽  
Dengue Virus ◽  
Hepg2 Cells ◽  
Cathepsin D ◽  
Fusion Inhibitor ◽  
Evidence Based ◽  
Ns1 Protein ◽  
Double Stranded Rna ◽  
A Site

We have recently proposed that amphisomes act as a site for translation and replication of dengue virus (DENV)-2 and that DENV-2 entry and replication are linked through an ongoing association with membranes of an endosomal–autophagosomal lineage. In this report, we present the results of an investigation into the interaction between DENV-3 and the autophagy machinery. Critically, treatment with the lysosomal fusion inhibitor l-asparagine differentiated the interaction of DENV-3 from that of DENV-2. Inhibition of fusion of autophagosomes and amphisomes with lysosomes resulted in decreased DENV-3 production, implying a role for the autophagolysosome in the DENV-3 life cycle. Evidence based upon the co-localization of LC3 and cathepsin D with double stranded RNA and NS1 protein, as assessed by confocal microscopy, support a model in which DENV-3 interacts with both amphisomes and autophagolysosomes. These results demonstrate that the interactions between DENV and the host cell autophagy machinery are complex and may be determined in part by virus-encoded factors.

scholarly journals Influenza Virus NS1 Protein Counteracts PKR-Mediated Inhibition of Replication

2000 ◽  
Vol 74 (13) ◽  
pp. 6203-6206 ◽  
Author(s):  
Michael Bergmann ◽  
Adolfo Garcia-Sastre ◽  
Elena Carnero ◽  
Hubert Pehamberger ◽  
Klaus Wolff ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Life Cycle ◽  
Protein Kinase ◽  
Gene Knockout ◽  
Ns1 Protein ◽  
Double Stranded Rna ◽  
Major Function ◽  
Ns1 Gene ◽  
Biological Relationship ◽  
Knockout Virus

ABSTRACT The availability of an influenza virus NS1 gene knockout virus (delNS1 virus) allowed us to establish the significance of the biological relationship between the influenza virus NS1 protein and double-stranded-RNA-activated protein kinase (PKR) in the life cycle and pathogenicity of influenza virus. Our results show that the lack of functional PKR permits the delNS1 virus to replicate in otherwise nonpermissive hosts, suggesting that the major function of the influenza virus NS1 protein is to counteract or prevent the PKR-mediated antiviral response.

Inhibition of Migration and Invasion of Hepatocarcinoma HepG2 Cells by Dietary Saponins via Targeting HIF-1α

2018 ◽  
Vol 18 (7) ◽  
pp. 1025-1031
Author(s):  
Cheng Luo ◽  
Di Wu ◽  
Meiling Chen ◽  
Wenhua Miao ◽  
Changfeng Xue ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Confocal Microscopy ◽  
Protein Expression ◽  
Mtt Assay ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Rt Pcr ◽  
Gene And Protein Expression ◽  
Simulated Hypoxia

Background: Different saponins from herbs have been used as tonic or functional foods, and for treatment of various diseases including cancers. Although clinical data has supported the function of these saponins, their underlying molecular mechanisms have not been well defined. Methods: With the simulated hypoxia created by 8 hours of Cu++ exposure and following 24 hour incubation with different concentration of saponins in HepG2 cells for MTT assay, migration and invasion assays, and for RT-PCR, and with each group of cells for immunofluorescence observation by confocal microscopy. Results： ZC-4 had the highest rate of inhibition of cell proliferation by MTT assay, and the highest inhibition of migration rate by in vitro scratch assay, while ZC-3 had the highest inhibition of invasion ratio by transwell assay. Under the same simulated hypoxia, the molecular mechanism of saponin function was conducted by measuring the gene expression of Hypoxia Inducible Factor (HIF)-1α through RT-PCR, in which ZC-3 showed a potent inhibition of gene HIF-1α. For the protein expression by immunofluorescence staining with confocal microscopy, HIF-1α was also inhibited by saponins, with the most potent one being ZC-4 after eight hours’ relatively hypoxia incubation. Conclusion: Saponins ZC-4 and ZC-3 have the potential to reduce HepG2 cell proliferation, migration and invasion caused by hypoxia through effectively inhibiting the gene and protein expression of HIF-1α directly and as antioxidant indirectly

scholarly journals Mannose 6-phosphate-independent targeting of cathepsin D to lysosomes in HepG2 cells.

1991 ◽  
Vol 266 (35) ◽  
pp. 23586-23592 ◽  
Author(s):  
S. Rijnboutt ◽  
A.J. Kal ◽  
H.J. Geuze ◽  
H. Aerts ◽  
G.J. Strous
Keyword(s):  
Hepg2 Cells ◽  
Cathepsin D ◽  
Mannose 6 Phosphate

scholarly journals Development of Bacteriophage Virus-Like Particle Vaccines Displaying Conserved Epitopes of Dengue Virus Non-Structural Protein 1

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 726
Author(s):  
Nikole L. Warner ◽  
Kathryn M. Frietze
Keyword(s):  
Dengue Virus ◽  
Population Based ◽  
Ns1 Protein ◽  
Structural Protein ◽  
Denv Serotypes ◽  
Conserved Regions ◽  
Virus Like Particle ◽  
Dependent Cell ◽  
Infected Cells ◽  
Plasma Leakage

Dengue virus (DENV) is a major global health problem, with over half of the world’s population at risk of infection. Despite over 60 years of efforts, no licensed vaccine suitable for population-based immunization against DENV is available. Here, we describe efforts to engineer epitope-based vaccines against DENV non-structural protein 1 (NS1). NS1 is present in DENV-infected cells as well as secreted into the blood of infected individuals. NS1 causes disruption of endothelial cell barriers, resulting in plasma leakage and hemorrhage. Immunizing against NS1 could elicit antibodies that block NS1 function and also target NS1-infected cells for antibody-dependent cell cytotoxicity. We identified highly conserved regions of NS1 from all four DENV serotypes. We generated synthetic peptides to these regions and chemically conjugated them to bacteriophage Qβ virus-like particles (VLPs). Mice were immunized two times with the candidate vaccines and sera were tested for the presence of antibodies that bound to the cognate peptide, recombinant NS1 from all four DENV serotypes, and DENV-2-infected cells. We found that two of the candidate vaccines elicited antibodies that bound to recombinant NS1, and one candidate vaccine elicited antibodies that bound to DENV-infected cells. These results show that an epitope-specific vaccine against conserved regions of NS1 could be a promising approach for DENV vaccines or therapeutics to bind circulating NS1 protein.

scholarly journals Mutation of Putative N-Glycosylation Sites on Dengue Virus NS4B Decreases RNA Replication

2015 ◽  
Vol 89 (13) ◽  
pp. 6746-6760 ◽  
Author(s):  
Nenavath Gopal Naik ◽  
Huey-Nan Wu
Keyword(s):  
Life Cycle ◽  
Recombinant Protein ◽  
Dengue Virus ◽  
Protein Expression ◽  
Nonstructural Protein ◽  
Recombinant Protein Expression ◽  
Rna Replication ◽  
Viral Production ◽  
Glycosylation Sites ◽  
Infected Cells

ABSTRACTDengue virus (DENV) nonstructural protein 4B (NS4B) is an endoplasmic reticulum (ER) membrane-associated protein, and mutagenesis studies have revealed its significance in viral genome replication. In this work, we demonstrated that NS4B is an N-glycosylated protein in virus-infected cells as well as in recombinant protein expression. NS4B is N glycosylated at residues 58 and 62 and exists in two forms, glycosylated and unglycosylated. We manipulated full-length infectious RNA clones and subgenomic replicons to generate N58Q, N62Q, and N58QN62Q mutants. Each of the single mutants had distinct effects, but the N58QN62Q mutation resulted in dramatic reduction of viral production efficiency without affecting secretion or infectivity of the virion in mammalian and mosquito C6/36 hosts. Real-time quantitative PCR (qPCR), subgenomic replicon, andtrans-complementation assays indicated that the N58QN62Q mutation affected RNA replication possibly by the loss of glycans. In addition, four intragenic mutations (S59Y, S59F, T66A, and A137T) were obtained from mammalian and/or mosquito C6/36 cell culture systems. All of these second-site mutations compensated for the replication defect of the N58QN62Q mutant without creating novel glycosylation sites.In vivoprotein stability analyses revealed that the N58QN62Q mutation alone or plus a compensatory mutation did not affect the stability of NS4B. Overall, our findings indicated that mutation of putative N-glycosylation sites affected the biological function of NS4B in the viral replication complex.IMPORTANCEThis is the first report to identify and reveal the biological significance of dengue virus (DENV) nonstructural protein 4B (NS4B) posttranslation N-glycosylation to the virus life cycle. The study demonstrated that NS4B is N glycosylated in virus-infected cells and in recombinant protein expression. NS4B is modified by glycans at Asn-58 and Asn-62. Functional characterization implied that DENV NS4B utilizes the glycosylation machinery in both mammalian and mosquito hosts. Four intragenic mutations were found to compensate for replication and subsequent viral production deficiencies without creating novel N-glycosylation sites or modulating the stabilities of the protein, suggesting that glycans may be involved in maintaining the NS4B protein conformation. NS4B glycans may be necessary elements of the viral life cycle, but compensatory mutations can circumvent their requirement. This novel finding may have broader implications in flaviviral biology as the most likely glycan at Asn-62 of NS4B is conserved in DENV serotypes and in some related flaviviruses.

Enhanced immune response by amphotericin B following NS1 protein prime-oral recombinant Salmonella vaccine boost vaccination protects mice from dengue virus challenge

Vaccine ◽  
2006 ◽  
Vol 24 (31-32) ◽  
pp. 5852-5861 ◽  
Author(s):  
Wen-Tssann Liu ◽  
Wei-Ting Lin ◽  
Chung-Chin Tsai ◽  
Chuan-Chang Chuang ◽  
Chin-Len Liao ◽  
...  
Keyword(s):  
Immune Response ◽  
Dengue Virus ◽  
Amphotericin B ◽  
Ns1 Protein ◽  
Virus Challenge ◽  
Boost Vaccination

scholarly journals Diterpenes/Diterpenoids and Their Derivatives as Potential Bioactive Leads against Dengue Virus: A Computational and Network Pharmacology Study

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6821
Author(s):  
Rasel Ahmed Khan ◽  
Rajib Hossain ◽  
Abolghasem Siyadatpanah ◽  
Khattab Al-Khafaji ◽  
Abul Bashar Ripon Khalipha ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Dengue Fever ◽  
Computational Study ◽  
Viral Proteins ◽  
Network Pharmacology ◽  
Binding Affinities ◽  
Ns1 Protein ◽  
Structural Protein ◽  
E Protein

Dengue fever is a dangerous infectious endemic disease that affects over 100 nations worldwide, from Africa to the Western Pacific, and is caused by the dengue virus, which is transmitted to humans by an insect bite of Aedes aegypti. Millions of citizens have died as a result of dengue fever and dengue hemorrhagic fever across the globe. Envelope (E), serine protease (NS3), RNA-directed RNA polymerase (NS5), and non-structural protein 1 (NS1) are mostly required for cell proliferation and survival. Some of the diterpenoids and their derivatives produced by nature possess anti-dengue viral properties. The goal of the computational study was to scrutinize the effectiveness of diterpenoids and their derivatives against dengue viral proteins through in silico study. Methods: molecular docking was performed to analyze the binding affinity of compounds against four viral proteins: the envelope (E) protein, the NS1 protein, the NS3 protein, and the NS5 protein. Results: among the selected drug candidates, triptolide, stevioside, alepterolic acid, sphaeropsidin A, methyl dodovisate A, andrographolide, caesalacetal, and pyrimethamine have demonstrated moderate to good binding affinities (−8.0 to −9.4 kcal/mol) toward the selected proteins: E protein, NS3, NS5, and NS1 whereas pyrimethamine exerts −7.5, −6.3, −7.8, and −6.6 kcal/mol with viral proteins, respectively. Interestingly, the binding affinities of these lead compounds were better than those of an FDA-approved anti-viral medication (pyrimethamine), which is underused in dengue fever. Conclusion: we can conclude that diterpenoids can be considered as a possible anti-dengue medication option. However, in vivo investigation is recommended to back up the conclusions of this study.

scholarly journals Potential of Peptide-Based Non-Structural Protein 1 (NS1) Inhibitor in Obstructing Dengue Virus (DENV) Replication

2021 ◽  
Vol 3 (1) ◽  
pp. 1-12
Author(s):  
Muhammad Mikail Athif Zhafir Asyura ◽  
Ahmad Fauzi ◽  
Fakhru Adlan Ayub
Keyword(s):  
Dengue Virus ◽  
Viral Replication ◽  
Dengue Fever ◽  
Immune Cells ◽  
Viral Protein ◽  
Viral Genome ◽  
Antiviral Drug ◽  
Ns1 Protein ◽  
Humoral Immune ◽  
Stimulation Of

Introduction: Dengue Virus (DENV) is the pathogen for human dengue fever and is responsible for 390 million infections per year. The viral genome produces about 10 viral protein products, one of them being NS1. The NS1 protein plays a key role in viral replication and stimulation of humoral immune cells, thus being the perfect candidate to create an effective antiviral drug or vaccine for dengue Methods: Dengue Virus (DENV) is the pathogen for human dengue fever and is responsible for 390 million infections per year. The viral genome produces about 10 viral protein products, one of them being NS1. The NS1 protein plays a key role in viral replication and stimulation of humoral immune cells, thus being the perfect candidate to create an effective antiviral drug or vaccine for dengue Conclusion: The review established promising results of using peptide-based intervention on NS1. Further in vivo and randomized controlled trials are advised to solidify the applicability and biosafety of the intervention    

scholarly journals Subversion of immunoproteasome subunit expression in dengue virus serotype 2-infected HepG2 cells

2017 ◽  
Vol 50 (1) ◽  
pp. 99-103
Author(s):  
Chye Sheng Gan ◽  
Pei Jean Lim ◽  
Muhammad Fazril Mohamad Razif ◽  
Rohana Yusof ◽  
Shatrah Othman
Keyword(s):  
Dengue Virus ◽  
Hepg2 Cells ◽  
Virus Serotype ◽  
Subunit Expression ◽  
Dengue Virus Serotype 2
Sign in / Sign up

Export Citation Format

Share Document