scholarly journals VP35 Knockdown Inhibits Ebola Virus Amplification and Protects against Lethal Infection in Mice

2006 ◽  
Vol 50 (3) ◽  
pp. 984-993 ◽  
Author(s):  
Sven Enterlein ◽  
Kelly L. Warfield ◽  
Dana L. Swenson ◽  
David A. Stein ◽  
Jeffery L. Smith ◽  
...  
Keyword(s):  
Cell Culture ◽  
Ebola Virus ◽  
Rna Viruses ◽  
Marburg Virus ◽  
Lethal Infection ◽  
Dependent Inhibition ◽  
Dna Analogs ◽  
Ebov Infection ◽  
Dose Dependent Inhibition ◽  
Positive Strand Rna

ABSTRACT Phosphorodiamidate morpholino oligomers (PMO) are a class of uncharged single-stranded DNA analogs modified such that each subunit includes a phosphorodiamidate linkage and morpholine ring. PMO antisense agents have been reported to effectively interfere with the replication of several positive-strand RNA viruses in cell culture. The filoviruses, Marburg virus and Ebola virus (EBOV), are negative-strand RNA viruses that cause up to 90% lethality in human outbreaks. There is currently no commercially available vaccine or efficacious therapeutic for any filovirus. In this study, PMO conjugated to arginine-rich cell-penetrating peptide (P-PMO) and nonconjugated PMO were assayed for the ability to inhibit EBOV infection in cell culture and in a mouse model of lethal EBOV infection. A 22-mer P-PMO designed to base pair with the translation start site region of EBOV VP35 positive-sense RNA generated sequence-specific and time- and dose-dependent inhibition of EBOV amplification in cell culture. The same oligomer provided complete protection to mice when administered before or after an otherwise lethal infection of EBOV. A corresponding nonconjugated PMO, as well as nonconjugated truncated versions of 16 and 19 base residues, provided length-dependent protection to mice when administered prophylactically. Together, these data suggest that antisense PMO and P-PMO have the potential to control EBOV infection and are promising therapeutic candidates.

Filoviruses

2020 ◽  
pp. 870-877
Author(s):  
Jan H. ter Meulen
Keyword(s):  
Ebola Virus ◽  
Rna Viruses ◽  
Great Apes ◽  
Marburg Virus ◽  
Haemorrhagic Fever ◽  
Viral Haemorrhagic Fever ◽  
Zoonotic Viruses ◽  
Bush Meat ◽  
Mode Of Transmission ◽  
Respiratory Droplets

Filoviruses are large RNA viruses, of which Ebola virus and Marburg virus cause the most severe forms of viral haemorrhagic fever and have been best-studied because of fear of their misuse as bioterrorism agents. These are zoonotic viruses with reservoirs, most likely fruit-eating bats, in the rainforests of tropical Africa, where they cause sporadic infections and outbreaks among great apes and humans. The primary mode of transmission of Ebola virus to humans often involves contact of hunters with dead animals that serve as amplifying hosts, especially gorillas, chimpanzees, and forest antelopes, whose meat is consumed as ‘bush meat’. Contact with bats has been implicated for both Marburg and Ebola virus. However, the viruses are highly infectious and are transmitted from the index case and subsequently from person to person by all body fluids, including sweat, respiratory droplets, and semen. The viruses can persist in convalescent patients for many months.

scholarly journals Exchange Protein Directly Activated by cAMP Modulates Ebola Virus Uptake into Vascular Endothelial Cells

Viruses ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 563 ◽  
Author(s):  
Aleksandra Drelich ◽  
Barbara Judy ◽  
Xi He ◽  
Qing Chang ◽  
Shangyi Yu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Ebola Virus ◽  
Vascular Endothelial Cells ◽  
Ex Vivo ◽  
Marburg Virus ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Ultrastructural Studies ◽  
Ebov Infection ◽  
Exchange Protein

Members of the family Filoviridae, including Ebola virus (EBOV) and Marburg virus (MARV), cause severe hemorrhagic fever in humans and nonhuman primates. Given their high lethality, a comprehensive understanding of filoviral pathogenesis is urgently needed. In the present studies, we revealed that the exchange protein directly activated by cAMP 1 (EPAC1) gene deletion protects vasculature in ex vivo explants from EBOV infection. Importantly, pharmacological inhibition of EPAC1 using EPAC-specific inhibitors (ESIs) mimicked the EPAC1 knockout phenotype in the ex vivo model. ESI treatment dramatically decreased EBOV infectivity in both ex vivo vasculature and in vitro vascular endothelial cells (ECs). Furthermore, postexposure protection of ECs against EBOV infection was conferred using ESIs. Protective efficacy of ESIs in ECs was observed also in MARV infection. Additional studies using a vesicular stomatitis virus pseudotype that expresses EBOV glycoprotein (EGP-VSV) confirmed that ESIs reduced infection in ECs. Ultrastructural studies suggested that ESIs blocked EGP-VSV internalization via inhibition of macropinocytosis. The inactivation of EPAC1 affects the early stage of viral entry after viral binding to the cell surface, but before early endosome formation, in a phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)-dependent manner. Our study delineated a new critical role of EPAC1 during EBOV uptake into ECs.

scholarly journals Human and Murine IFIT1 Proteins Do Not Restrict Infection of Negative-Sense RNA Viruses of the Orthomyxoviridae, Bunyaviridae, and Filoviridae Families

2015 ◽  
Vol 89 (18) ◽  
pp. 9465-9476 ◽  
Author(s):  
Amelia K. Pinto ◽  
Graham D. Williams ◽  
Kristy J. Szretter ◽  
James P. White ◽  
José Luiz Proença-Módena ◽  
...  
Keyword(s):  
Cell Culture ◽  
Antiviral Activity ◽  
Ebola Virus ◽  
Rna Viruses ◽  
Ectopic Expression ◽  
A549 Cells ◽  
Host Protein ◽  
Interferon Response ◽  
Restriction Factor ◽  
Negative Sense

ABSTRACTInterferon-induced protein with tetratricopeptide repeats 1 (IFIT1) is a host protein with reported cell-intrinsic antiviral activity against several RNA viruses. The proposed basis for the activity against negative-sense RNA viruses is the binding to exposed 5′-triphosphates (5′-ppp) on the genome of viral RNA. However, recent studies reported relatively low binding affinities of IFIT1 for 5′-ppp RNA, suggesting that IFIT1 may not interact efficiently with this moiety under physiological conditions. To evaluate the ability of IFIT1 to have an impact on negative-sense RNA viruses, we infectedIfit1−/−and wild-type control mice and primary cells with four negative-sense RNA viruses (influenza A virus [IAV], La Crosse virus [LACV], Oropouche virus [OROV], and Ebola virus) corresponding to three distinct families. Unexpectedly, a lack ofIfit1gene expression did not result in increased infection by any of these viruses in cell culture. Analogously, morbidity, mortality, and viral burdens in tissues were identical betweenIfit1−/−and control mice after infection with IAV, LACV, or OROV. Finally, deletion of the human IFIT1 protein in A549 cells did not affect IAV replication or infection, and reciprocally, ectopic expression of IFIT1 in HEK293T cells did not inhibit IAV infection. To explain the lack of antiviral activity against IAV, we measured the binding affinity of IFIT1 for RNA oligonucleotides resembling the 5′ ends of IAV gene segments. The affinity for 5′-ppp RNA was approximately 10-fold lower than that for non-2′-O-methylated (cap 0) RNA oligonucleotides. Based on this analysis, we conclude that IFIT1 is not a dominant restriction factor against negative-sense RNA viruses.IMPORTANCENegative-sense RNA viruses, including influenza virus and Ebola virus, have been responsible for some of the most deadly outbreaks in recent history. The host interferon response and induction of antiviral genes contribute to the control of infections by these viruses. IFIT1 is highly induced after virus infection and reportedly has antiviral activity against several RNA and DNA viruses. However, its role in restricting infection by negative-sense RNA viruses remains unclear. In this study, we evaluated the ability of IFIT1 to inhibit negative-sense RNA virus replication and pathogenesis bothin vitroandin vivo. Detailed cell culture and animal studies demonstrated that IFIT1 is not a dominant restriction factor against three different families of negative-sense RNA viruses.

Ebola virus: new insights into disease aetiopathology and possible therapeutic interventions

2004 ◽  
Vol 6 (20) ◽  
pp. 1-24 ◽  
Author(s):  
Thomas W. Geisbert ◽  
Lisa E. Hensley
Keyword(s):  
Ebola Virus ◽  
Clinical Presentation ◽  
Case Fatality ◽  
Regulatory Elements ◽  
Current Understanding ◽  
Therapeutic Interventions ◽  
Therapeutic Modality ◽  
Washington Dc ◽  
Lethal Infection ◽  
Ebov Infection

Ebola virus (EBOV) gained public notoriety in the last decade largely as a consequence of the highly publicised isolation of a new EBOV species in a suburb of Washington, DC, in 1989, together with the dramatic clinical presentation of EBOV infection and high case-fatality rate in Africa (near 90% in some outbreaks), and the unusual and striking morphology of the virus. Furthermore, there are no vaccines or effective therapies currently available. Progress in understanding the origins of the pathophysiological changes that make EBOV infections of humans so devastating has been slow, primarily because these viruses require special containment for safe research. However, an increasing understanding of the mechanisms of EBOV pathogenesis, facilitated by the development of new tools to elucidate critical regulatory elements in the viral life cycle, is providing new targets that can be exploited for therapeutic interventions. Notably, identifying factors triggering the haemorrhagic complications that characterise EBOV infections led to the development of a strategy to modulate coagulopathy; this therapeutic modality successfully mitigated the effects of EBOV haemorrhagic fever in nonhuman primates. This review summarises our current understanding of EBOV pathogenesis and discusses various approaches to therapeutic intervention based on our current understanding of how EBOV produces a lethal infection.

scholarly journals Functional Analysis of RNA Structures Present at the 3′ Extremity of the Murine Norovirus Genome: the Variable Polypyrimidine Tract Plays a Role in Viral Virulence

2010 ◽  
Vol 84 (6) ◽  
pp. 2859-2870 ◽  
Author(s):  
Dalan Bailey ◽  
Ioannis Karakasiliotis ◽  
Surender Vashist ◽  
Liliane Man Wah Chung ◽  
Jivan Reese ◽  
...  
Keyword(s):  
Cell Culture ◽  
Host Cell ◽  
Virus Replication ◽  
Untranslated Region ◽  
Rna Viruses ◽  
Murine Norovirus ◽  
Polypyrimidine Tract ◽  
Rna Structures ◽  
Positive Strand ◽  
Positive Strand Rna

ABSTRACT Interactions of host cell factors with RNA sequences and structures in the genomes of positive-strand RNA viruses play various roles in the life cycles of these viruses. Our understanding of the functional RNA elements present in norovirus genomes to date has been limited largely to in vitro analysis. However, we recently used reverse genetics to identify evolutionarily conserved RNA structures and sequences required for norovirus replication. We have now undertaken a more detailed analysis of RNA structures present at the 3′ extremity of the murine norovirus (MNV) genome. Biochemical data indicate the presence of three stable stem-loops, including two in the untranslated region, and a single-stranded polypyrimidine tract [p(Y)] of variable length between MNV isolates, within the terminal stem-loop structure. The well-characterized host cell pyrimidine binding proteins PTB and PCBP bound the 3′-untranslated region via an interaction with this variable sequence. Viruses lacking the p(Y) tract were viable both in cell culture and upon mouse infection, demonstrating that this interaction was not essential for virus replication. However, competition analysis with wild-type MNV in cell culture indicated that the loss of the p(Y) tract was associated with a fitness cost. Furthermore, a p(Y)-deleted mutant showed a reduction in virulence in the STAT1−/− mouse model, highlighting the role of RNA structures in norovirus pathogenesis. This work highlights how, like with other positive-strand RNA viruses, RNA structures present at the termini of the norovirus genome play important roles in virus replication and virulence.

scholarly journals Interferon-Induced HERC5 Inhibits Ebola Virus Particle Production and Is Antagonized by Ebola Glycoprotein

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2399
Author(s):  
Ermela Paparisto ◽  
Nina R. Hunt ◽  
Daniel S. Labach ◽  
Macon D. Coleman ◽  
Eric J. Di Gravio ◽  
...  
Keyword(s):  
Particle Production ◽  
Ebola Virus ◽  
Marburg Virus ◽  
Antiviral Protein ◽  
Virus Like Particle ◽  
Ebov Infection ◽  
Necessary And Sufficient ◽  
Virus Particle Production ◽  
Transcription And Replication

Survival following Ebola virus (EBOV) infection correlates with the ability to mount an early and robust interferon (IFN) response. The host IFN-induced proteins that contribute to controlling EBOV replication are not fully known. Among the top genes with the strongest early increases in expression after infection in vivo is IFN-induced HERC5. Using a transcription- and replication-competent VLP system, we showed that HERC5 inhibits EBOV virus-like particle (VLP) replication by depleting EBOV mRNAs. The HERC5 RCC1-like domain was necessary and sufficient for this inhibition and did not require zinc finger antiviral protein (ZAP). Moreover, we showed that EBOV (Zaire) glycoprotein (GP) but not Marburg virus GP antagonized HERC5 early during infection. Our data identify a novel ‘protagonist–antagonistic’ relationship between HERC5 and GP in the early stages of EBOV infection that could be exploited for the development of novel antiviral therapeutics.

scholarly journals Identification of a DNA aptamer that inhibits sclerostin's antagonistic effect on Wnt signalling

2011 ◽  
Vol 434 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Ka To Shum ◽  
Celine Chan ◽  
Ching-Man Leung ◽  
Julian A. Tanner
Keyword(s):  
Cell Culture ◽  
Therapeutic Potential ◽  
Solid Phase ◽  
Antagonistic Effect ◽  
Negative Regulator ◽  
Dna Aptamer ◽  
Titration Calorimetry ◽  
Osteoporosis Therapy ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition

Sclerostin is an extracellular negative regulator of bone formation that is a recognized therapeutic target for osteoporosis therapy. In the present study, we performed DNA aptamer selection against sclerostin, then characterized aptamer–sclerostin binding and the ability to inhibit sclerostin function in cell culture. We show that a selected DNA aptamer was highly selective for binding to sclerostin with affinities in the nanomolar range as determined by solid-phase assays and by isothermal titration calorimetry. Binding between sclerostin and the aptamer was exothermic and enthalpically driven. CD confirmed that the aptamer had temperature-dependent parallel G-quadruplex characteristics. The aptamer was stabilized with 3′ inverted thymidine to investigate efficacy at inhibiting sclerostin function in cell culture. The stabilized DNA aptamer showed potent and specific dose-dependent inhibition of sclerostin's antagonistic effect on Wnt activity using a reporter assay. Taken together, the present findings suggest an alternative approach to inhibiting sclerostin function with therapeutic potential.

Differences between antigenic determinants of pig and cat zona pellucida proteins

Reproduction ◽  
2000 ◽  
pp. 15-23 ◽  
Author(s):  
K Jewgenow ◽  
M Rohleder ◽  
I Wegner
Keyword(s):  
In Vitro Fertilization ◽  
Zona Pellucida ◽  
Antigenic Determinants ◽  
Vitro Fertilization ◽  
Contraceptive Vaccine ◽  
Sperm Binding ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.

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