scholarly journals A polyomavirus peptide binds to the capsid VP1 pore and has potent antiviral activity against BK and JC polyomaviruses

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Joshua R Kane ◽  
Susan Fong ◽  
Jacob Shaul ◽  
Alexandra Frommlet ◽  
Andreas O Frank ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Specific Binding ◽  
Structural Protein ◽  
Single Digit ◽  
Bk Polyomavirus ◽  
Concomitant Reduction ◽  
Model Cell ◽  
Novel Strategy ◽  
Key Residues

In pursuit of therapeutics for human polyomaviruses, we identified a peptide derived from the BK polyomavirus (BKV) minor structural proteins VP2/3 that is a potent inhibitor of BKV infection with no observable cellular toxicity. The thirteen-residue peptide binds to major structural protein VP1 with single-digit nanomolar affinity. Alanine-scanning of the peptide identified three key residues, substitution of each of which results in ~1000 fold loss of binding affinity with a concomitant reduction in antiviral activity. Structural studies demonstrate specific binding of the peptide to the pore of pentameric VP1. Cell-based assays demonstrate nanomolar inhibition (EC50) of BKV infection and suggest that the peptide acts early in the viral entry pathway. Homologous peptide exhibits similar binding to JC polyomavirus VP1 and inhibits infection with similar potency to BKV in a model cell line. Lastly, these studies validate targeting the VP1 pore as a novel strategy for the development of anti-polyomavirus agents.

scholarly journals A VP2/3-derived peptide exhibits potent antiviral activity against BK and JC polyomaviruses by targeting a novel VP1 binding site

2019 ◽  
Author(s):  
Joshua R. Kane ◽  
Susan Fong ◽  
Jacob Shaul ◽  
Alexandra Frommlet ◽  
Andreas O. Frank ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Binding Site ◽  
Viral Entry ◽  
Specific Binding ◽  
Peptide Binding ◽  
Structural Protein ◽  
Amino Acid Peptide ◽  
Peptide Binding Site ◽  
Concomitant Reduction ◽  
Novel Target

ABSTRACTIn pursuit of effective therapeutics for human polyomaviruses, we identified a peptide derived from the BK polyomavirus (BKV) minor structural proteins VP2/3 that is a potent inhibitor of BKV infection with no observable cellular toxicity. The thirteen amino acid peptide binds to major structural protein VP1 in a new location within the pore with a low nanomolar KD. Alanine scanning of the peptide identified three key residues, substitution of each of which results in ∼1000-fold loss of affinity with a concomitant reduction in antiviral activity. NMR spectroscopy and an X-ray structurally-guided model demonstrate specific binding of the peptide to the pore of the VP1 pentamer that constitutes the BKV capsid. Cell-based assays with the peptide demonstrate nanomolar inhibition of BKV infection and suggest that the peptide likely blocks the viral entry pathway between endocytosis and escape from the host cell ER. The peptide motif is highly conserved among the polyomavirus clade, and homologous peptides exhibit similar binding properties for JC polyomavirus and inhibit infection with similar potency to BKV in a model cell line. Substitutions within VP1 or VP2/3 residues involved in VP1-peptide interaction negatively impact viral infectivity, potentially indicating the peptide-binding site within the VP1 pore is relevant for VP1-VP2/3 interactions. The inhibitory potential of the peptide-binding site first reported here may present a novel target for development of new anti-polyomavirus therapies. In summary, we present the first anti-polyomavirus inhibitor that acts via a novel mechanism of action by specifically targeting the pore of VP1.

scholarly journals Phytochemical Characterization of Olea europea Leaf Extracts and Assessment of Their Anti-Microbial and Anti-HSV-1 Activity

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1085
Author(s):  
Ichrak Ben-Amor ◽  
Maria Musarra-Pizzo ◽  
Antonella Smeriglio ◽  
Manuela D’Arrigo ◽  
Rosamaria Pennisi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Antiviral Effect ◽  
Vero Cells ◽  
Biological Properties ◽  
Leaf Extracts ◽  
Gram Positive Bacteria ◽  
Entry Assay ◽  
Olea Europea ◽  
Hsv 1

Owing to the richness of bioactive compounds, Olea europea leaf extracts exhibit a range of health effects. The present research evaluated the antibacterial and antiviral effect of leaf extracts obtained from Olea europea L. var. sativa (OESA) and Olea europea var. sylvestris (OESY) from Tunisia. LC-DAD-ESI-MS analysis allowed the identification of different compounds that contributed to the observed biological properties. Both OESA and OESY were active against Gram-positive bacteria (MIC values between 7.81 and 15.61 μg/mL and between 15.61 and 31.25 μg/mL against Staphylococcus aureus ATCC 6538 for OESY and OESA, respectively). The antiviral activity against the herpes simplex type 1 (HSV-1) was assessed on Vero cells. The results of cell viability indicated that Olea europea leaf extracts were not toxic to cultured Vero cells. The half maximal cytotoxic concentration (CC50) values for OESA and OESY were 0.2 mg/mL and 0.82 mg/mL, respectively. Furthermore, both a plaque reduction assay and viral entry assay were used to demonstrate the antiviral activity. In conclusion, Olea europea leaf extracts demonstrated a bacteriostatic effect, as well as remarkable antiviral activity, which could provide an alternative treatment against resistant strains.

scholarly journals Antiviral activity of the green marine alga Ulva fasciata on the replication of human metapneumovirus

2010 ◽  
Vol 52 (1) ◽  
pp. 03-10 ◽  
Author(s):  
Gabriella da Silva Mendes ◽  
Angélica Ribeiro Soares ◽  
Fernanda Otaviano Martins ◽  
Maria Carolina Maciel de Albuquerque ◽  
Sonia Soares Costa ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Marine Algae ◽  
Marine Alga ◽  
Biological Properties ◽  
Human Metapneumovirus ◽  
The Other ◽  
Virucidal Activity ◽  
Ulva Fasciata ◽  
Viral Particles

We evaluated the antiviral activity of the marine alga, Ulva fasciata, collected from Rasa beach and Forno beach, Búzios, Rio de Janeiro, Brazil on the replication of human metapneumovirus (HMPV). The algae extracts were prepared using three different methodologies to compare the activity of different groups of chemical composites obtained through these different methodologies. Four out of the six extracts inhibited nearly 100% of viral replication. The results demonstrated that the majority of the extracts (five out of six) possess virucidal activity and therefore have the ability to interact with the extracellular viral particles and prevent the infection. On the other hand, only two extracts (from Forno beach, obtained by maceration and maceration of the decoction) were able to interact with cell receptors, hindering the viral entry. Finally, only the extract of algae collected at Forno beach, obtained by maceration presented intracellular activity. To our knowledge, this is a pioneer study on antiviral activity of marine algae against HMPV. It is also the first on antiviral activity against HMPV ever done in Brazil. The study also shows the effect of different environment factors and different chemical procedures used to obtain the extract on its biological properties.

scholarly journals The Combined Use of Alphavirus Replicons and Pseudoinfectious Particles for the Discovery of Antivirals Derived from Natural Products

2014 ◽  
Vol 20 (5) ◽  
pp. 673-680 ◽  
Author(s):  
Phillip C. Delekta ◽  
Avi Raveh ◽  
Martha J. Larsen ◽  
Pamela J. Schultz ◽  
Giselle Tamayo-Castillo ◽  
...  
Keyword(s):  
Life Cycle ◽  
Antiviral Activity ◽  
Viral Entry ◽  
Particle System ◽  
Antiviral Agents ◽  
Viral Life Cycle ◽  
Genome Replication ◽  
Bacterial Strains ◽  
Antiviral Compounds ◽  
Western Equine Encephalitis

Alphaviruses are a prominent class of reemergent pathogens due to their globally expanding ranges, potential for lethality, and possible use as bioweapons. The absence of effective treatments for alphaviruses highlights the need for innovative strategies to identify antiviral agents. Primary screens that use noninfectious self-replicating RNAs, termed replicons, have been used to identify potential antiviral compounds for alphaviruses. Only inhibitors of viral genome replication, however, will be identified using replicons, which excludes many other druggable steps in the viral life cycle. To address this limitation, we developed a western equine encephalitis virus pseudoinfectious particle system that reproduces several crucial viral life cycle steps in addition to genome replication. We used this system to screen a library containing ~26,000 extracts derived from marine microbes, and we identified multiple bacterial strains that produce compounds with potential antiviral activity. We subsequently used pseudoinfectious particle and replicon assays in parallel to counterscreen candidate extracts, and followed antiviral activity during biochemical fractionation and purification to differentiate between inhibitors of viral entry and genome replication. This novel process led to the isolation of a known alphavirus entry inhibitor, bafilomycin, thereby validating the approach for the screening and identification of potential antiviral compounds.

scholarly journals Identification of Antinorovirus Genes in Human Cells Using Genome-Wide CRISPR Activation Screening

2018 ◽  
Vol 93 (1) ◽  
Author(s):  
Robert C. Orchard ◽  
Meagan E. Sullender ◽  
Bria F. Dunlap ◽  
Dale R. Balce ◽  
John G. Doench ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Human Cells ◽  
Gene Promoters ◽  
Murine Norovirus ◽  
Individual Gene ◽  
Genome Wide ◽  
Host Genes ◽  
Crispr Activation

ABSTRACT Noroviruses (NoVs) are a leading cause of gastroenteritis worldwide, yet host factors that restrict NoV replication are not well understood. Here, we use a CRISPR activation genome-wide screening to identify host genes that can inhibit murine norovirus (MNoV) replication in human cells. Our screens identified with high confidence 49 genes that can inhibit MNoV infection when overexpressed. A significant number of these genes are in interferon and immune regulation signaling networks, but surprisingly, the majority of the genes identified are neither associated with innate or adaptive immunity nor associated with any antiviral activity. Confirmatory studies of eight of the genes validate the initial screening data. Mechanistic studies on TRIM7 demonstrated a conserved role of the molecule in mouse and human cells in restricting MNoV in a step of infection after viral entry. Furthermore, we demonstrate that two isoforms of TRIM7 have differential antiviral activity. Taken together, these data provide a resource for understanding norovirus biology and demonstrate a robust methodology for identifying new antiviral molecules. IMPORTANCE Norovirus is one of the leading causes of food-borne illness worldwide. Despite its prevalence, our understanding of norovirus biology is limited due to the difficulty in growing human norovirus in vitro and a lack of an animal model. Murine norovirus (MNoV) is a model norovirus system because MNoV replicates robustly in cell culture and in mice. To identify host genes that can restrict norovirus replication when overexpressed, we performed genome-wide CRISPR activation screens to induce gene overexpression at the native locus through recruitment of transcriptional activators to individual gene promoters. We found 49 genes that could block murine norovirus replication in human cells. Several of these genes are associated with classical immune signaling pathways, while many of the molecules we identified have not been previously associated with antiviral activity. Our data are a resource for those studying noroviruses, and we provide a robust approach to identify novel antiviral genes.

scholarly journals Analysis of IFITM-IFITM Interactions by a Flow Cytometry-Based FRET Assay

2019 ◽  
Vol 20 (16) ◽  
pp. 3859 ◽  
Author(s):  
Michael Winkler ◽  
Florian Wrensch ◽  
Pascale Bosch ◽  
Maike Knoth ◽  
Michael Schindler ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Protein Interactions ◽  
Viral Entry ◽  
Cellular Localization ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Yellow Fluorescent Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Protein Protein Interactions

The interferon-induced transmembrane proteins 1–3 (IFITM1–3) inhibit host cell entry of several viruses. However, it is incompletely understood how IFITM1–3 exert antiviral activity. Two phenylalanine residues, F75 and F78, within the intramembrane domain 1 (IM1) were previously shown to be required for IFITM3/IFITM3 interactions and for inhibition of viral entry, suggesting that IFITM/IFITM interactions might be pivotal to antiviral activity. Here, we employed a fluorescence resonance energy transfer (FRET) assay to analyze IFITM/IFITM interactions. For assay calibration, we equipped two cytosolic, non-interacting proteins, super yellow fluorescent protein (SYFP) and super cyan fluorescent protein (SCFP), with signals that target proteins to membrane rafts and also analyzed a SCFP-SYFP fusion protein. This strategy allowed us to discriminate background signals resulting from colocalization of proteins at membrane subdomains from signals elicited by protein–protein interactions. Coexpression of IFITM1–3 and IFITM5 fused to fluorescent proteins elicited strong FRET signals, and mutation of F75 and F78 in IFITM3 (mutant IFITM3-FF) abrogated antiviral activity, as expected, but did not alter cellular localization and FRET signals. Moreover, IFITM3-FF co-immunoprecipitated efficiently with wild type (wt) IFITM3, lending further support to the finding that lack of antiviral activity of IFITM3-FF was not due to altered membrane targeting or abrogated IFITM3-IFITM3 interactions. Collectively, we report an assay that allows quantifying IFITM/IFITM interactions. Moreover, we confirm residues F75 and F78 as critical for antiviral activity but also show that these residues are dispensable for IFITM3 membrane localization and IFITM3/IFITM3 interactions.

scholarly journals Specific Targeting of Lymphoma Cells Using Semisynthetic Anti-Idiotype Shark Antibodies

2020 ◽  
Vol 11 ◽  
Author(s):  
Arturo Macarrón Palacios ◽  
Julius Grzeschik ◽  
Lukas Deweid ◽  
Simon Krah ◽  
Stefan Zielonka ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
Specific Binding ◽  
B Cell Lymphoma ◽  
Therapeutic Window ◽  
Patient Specific ◽  
Soluble Antigen ◽  
Single Digit ◽  
Lymphoma Therapy

The B-cell receptor (BCR) is a key player of the adaptive immune system. It is a unique part of immunoglobulin (Ig) molecules expressed on the surface of B cells. In case of many B-cell lymphomas, the tumor cells express a tumor-specific and functionally active BCR, also known as idiotype. Utilizing the idiotype as target for lymphoma therapy has emerged to be demanding since the idiotype differs from patient to patient. Previous studies have shown that shark-derived antibody domains (vNARs) isolated from a semi-synthetic CDR3-randomized library allow for the rapid generation of anti-idiotype binders. In this study, we evaluated the potential of generating patient-specific binders against the idiotype of lymphomas. To this end, the BCRs of three different lymphoma cell lines SUP-B8, Daudi, and IM-9 were identified, the variable domains were reformatted and the resulting monoclonal antibodies produced. The SUP-B8 BCR served as antigen in fluorescence-activated cell sorting (FACS)-based screening of the yeast-displayed vNAR libraries which resulted after three rounds of screening in the enrichment of antigen-binding vNARs. Five vNARs were expressed as Fc fusion proteins and consequently analyzed for their binding to soluble antigen using biolayer interferometry (BLI) revealing binding constants in the lower single-digit nanomolar range. These variants showed specific binding to the parental SUP-B8 cell line confirming a similar folding of the recombinantly expressed proteins compared with the native cell surface-presented BCR. First initial experiments to utilize the generated vNAR-Fc variants for BCR-clustering to induce apoptosis or ADCC/ADCP did not result in a significant decrease of cell viability. Here, we report an alternative approach for a personalized B-cell lymphoma therapy based on the construction of vNAR-Fc antibody-drug conjugates to enable specific killing of malignant B cells, which may widen the therapeutic window for B-cell lymphoma therapy.

Novel quaternary phosphonium-type cationic polyacrylamide and elucidation of dual-functional antibacterial/antiviral activity

RSC Advances ◽  
2014 ◽  
Vol 4 (87) ◽  
pp. 46887-46895 ◽  
Author(s):  
Yan Xue ◽  
Yuanfeng Pan ◽  
Huining Xiao ◽  
Yi Zhao
Keyword(s):  
Cell Membrane ◽  
Antiviral Activity ◽  
Viral Entry ◽  
Cationic Polyacrylamide ◽  
Dual Functional

A novel quaternary phosphonium-type cationic polyacrylamide, which can kill bacteria by destroying the cell membrane, as well as inactivate adenovirus by blocking the viral entry, is developed.

scholarly journals Structural insight into DNA binding and oligomerization of the multifunctional Cox protein of bacteriophage P2

2013 ◽  
Vol 42 (4) ◽  
pp. 2725-2735 ◽  
Author(s):  
Ronnie P.-A. Berntsson ◽  
Richard Odegrip ◽  
Wilhelmina Sehlén ◽  
Karin Skaar ◽  
Linda M. Svensson ◽  
...  
Keyword(s):  
Dna Binding ◽  
Protein Function ◽  
Specific Binding ◽  
Gene Products ◽  
Structural Determinants ◽  
Bacteriophage P2 ◽  
Defective Prophage ◽  
Key Residues ◽  
Functional Analyses ◽  
Insight Into

Abstract The Cox protein from bacteriophage P2 is a small multifunctional DNA-binding protein. It is involved in site-specific recombination leading to P2 prophage excision and functions as a transcriptional repressor of the P2 Pc promoter. Furthermore, it transcriptionally activates the unrelated, defective prophage P4 that depends on phage P2 late gene products for lytic growth. In this article, we have investigated the structural determinants to understand how P2 Cox performs these different functions. We have solved the structure of P2 Cox to 2.4 Å resolution. Interestingly, P2 Cox crystallized in a continuous oligomeric spiral with its DNA-binding helix and wing positioned outwards. The extended C-terminal part of P2 Cox is largely responsible for the oligomerization in the structure. The spacing between the repeating DNA-binding elements along the helical P2 Cox filament is consistent with DNA binding along the filament. Functional analyses of alanine mutants in P2 Cox argue for the importance of key residues for protein function. We here present the first structure from the Cox protein family and, together with previous biochemical observations, propose that P2 Cox achieves its various functions by specific binding of DNA while wrapping the DNA around its helical oligomer.

scholarly journals A Novel Substance Purified from Perilla Frutescens Britton Inhibits an Early Stage of HIV-1 Replication without Blocking Viral Adsorption

2002 ◽  
Vol 13 (5) ◽  
pp. 283-288 ◽  
Author(s):  
T Kawahata ◽  
T Otake ◽  
H Mori ◽  
Y Kojima ◽  
I Oishi ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Viral Entry ◽  
Cytopathic Effect ◽  
Early Stage ◽  
Perilla Frutescens ◽  
Viral Strain ◽  
Viral Particles ◽  
Viral Adsorption ◽  
Hiv 1

Pf-gp6, a 6 kDa anti-degranulation glycoprotein purified from the extract of Perilla frutescens, was examined for its antiviral activity against HIV-1 and HIV-2 in vitro. HIV-1-induced cytopathic effect and proviral DNA synthesis were inhibited in the presence of Pf-gp6. The 50% inhibitory concentrations of Pf-gp6 for various HIV-1 strains, including clinical isolates and CCR5-using (R5) HIV-1, ranged between 1.3 and 71.0 μg/ml, depending on the combination of viral strain and host cell. Furthermore, Pf-gp6 did not directly inactivate infectious viral particles. A time-of-addition experiment revealed that Pf-gp6 lost its activity before zidovudine but after the CXCR-4 antagonist AMD3100 during the early stage of viral infection. Although the pinpoint target of Pf-gp6 remains to be elucidated, it may interfere with a step between viral entry and reverse transcription.

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