Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.098
Filtrar
1.
Sci Adv ; 10(14): eadl5012, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38569033

RESUMO

The ß-coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the global COVID-19 pandemic. Coronaviral Envelope (E) proteins are pentameric viroporins that play essential roles in assembly, release, and pathogenesis. We developed a nondisruptive tagging strategy for SARS-CoV-2 E and find that, at steady state, it localizes to the Golgi and to lysosomes. We identify sequences in E, conserved across Coronaviridae, responsible for endoplasmic reticulum-to-Golgi export, and relate this activity to interaction with COP-II via SEC24. Using proximity biotinylation, we identify an ADP ribosylation factor 1/adaptor protein-1 (ARFRP1/AP-1)-dependent pathway allowing Golgi-to-lysosome trafficking of E. We identify sequences in E that bind AP-1, are conserved across ß-coronaviruses, and allow E to be trafficked from Golgi to lysosomes. We show that E acts to deacidify lysosomes and, by developing a trans-complementation assay for SARS-CoV-2 structural proteins, that lysosomal delivery of E and its viroporin activity is necessary for efficient viral replication and release.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , Proteínas do Envelope Viral/metabolismo , Fator de Transcrição AP-1/metabolismo , Pandemias , Replicação Viral , Lisossomos/metabolismo , Fatores de Ribosilação do ADP/metabolismo
2.
PLoS Pathog ; 20(4): e1012139, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38578790

RESUMO

Alpha herpesviruses naturally infect the peripheral nervous system, and can spread to the central nervous system, causing severe debilitating or deadly disease. Because alpha herpesviruses spread along synaptic circuits, and infected neurons exhibit altered electrophysiology and increased spontaneous activity, we hypothesized that alpha herpesviruses use activity-dependent synaptic vesicle-like regulated secretory mechanisms for egress and spread from neurons. Using live-cell fluorescence microscopy, we show that Pseudorabies Virus (PRV) particles use the constitutive Rab6 post-Golgi secretory pathway to exit from the cell body of primary neurons, independent of local calcium signaling. Some PRV particles colocalize with Rab6 in the proximal axon, but we did not detect colocalization/co-transport in the distal axon. Thus, the specific secretory mechanisms used for viral egress from axons remains unclear. To address the role of neuronal activity more generally, we used a compartmentalized neuron culture system to measure the egress and spread of PRV from axons, and pharmacological and optogenetics approaches to modulate neuronal activity. Using tetrodotoxin to silence neuronal activity, we observed no inhibition, and using potassium chloride or optogenetics to elevate neuronal activity, we also show no increase in virus spread from axons. We conclude that PRV egress from neurons uses constitutive secretory mechanisms: generally, activity-independent mechanisms in axons, and specifically, the constitutive Rab6 post-Golgi secretory pathway in cell bodies.


Assuntos
Alphaherpesvirinae , Herpesvirus Suídeo 1 , Pseudorraiva , Animais , Corpo Celular/metabolismo , Proteínas do Envelope Viral/metabolismo , Axônios , Alphaherpesvirinae/metabolismo , Neurônios , Herpesvirus Suídeo 1/metabolismo , Pseudorraiva/metabolismo , Exocitose
3.
mBio ; 15(4): e0032124, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38426750

RESUMO

Human immunodeficiency virus type 1 typically requires a high density of CD4 for efficient entry as a mechanism to target CD4+ T cells (T-tropic), with CCR5 being used most often as the coreceptor. When target T cells are limiting, the virus can evolve to infect cells with a low density of CD4 such as macrophages (M-tropic). The entry phenotype is known to be encoded in the viral Env protein on the surface of the virus particle. Using data showing a dose response for infectivity based on CD4 surface density, we built a model consistent with T-tropic viruses requiring multiple CD4 molecules to mediate infection, whereas M-tropic viruses can infect cells using a single CD4 receptor molecule interaction. We also found that T-tropic viruses bound to the surface of cells with a low density of CD4 are released more slowly than M-tropic viruses which we modeled to be due to multiple interactions of the T-tropic virus with multiple CD4 molecules to allow the initial stable binding. Finally, we found that some M-tropic Env proteins, as the gp120 subunit, possess an enhanced affinity for CD4 compared with their T-tropic pair, indicating that the evolution of macrophage tropism can be reflected both in the closed Env trimer conformation on the virion surface and, in some cases, also in the open confirmation of gp120 Env. Collectively, these studies reveal differences in the stoichiometry of interaction of T-tropic and M-tropic viruses with CD4 and start to identify the basis of binding differences at the biochemical level. IMPORTANCE: Human immunodeficiency virus type 1 normally targets CD4+ T cells for viral replication. When T cells are limiting, the virus can evolve to infect myeloid cells. The evolutionary step involves a change from requiring a high surface density of CD4 for entry to being able to infect cells with a low density of CD4, as is found on myeloid lineage cells such as macrophage and microglia. Viruses able to infect macrophages efficiently are most often found in the CNS late in the disease course, and such viruses may contribute to neurocognitive impairment. Here, we examine the CD4 binding properties of the viral Env protein to explore these two different entry phenotypes.


Assuntos
HIV-1 , Humanos , Antígenos CD4/metabolismo , Linfócitos T CD4-Positivos , Produtos do Gene env/metabolismo , HIV-1/fisiologia , Macrófagos/metabolismo , Receptores CCR5/metabolismo , Proteínas do Envelope Viral/metabolismo , Produtos do Gene env do Vírus da Imunodeficiência Humana
4.
FEBS Lett ; 598(7): 758-773, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38436147

RESUMO

The human Mediator complex subunit MED25 binds transactivation domains (TADs) present in various cellular and viral proteins using two binding interfaces, named H1 and H2, which are found on opposite sides of its ACID domain. Here, we use and compare deep learning methods to characterize human MED25-TAD interfaces and assess the predicted models to published experimental data. For the H1 interface, AlphaFold produces predictions with high-reliability scores that agree well with experimental data, while the H2 interface predictions appear inconsistent, preventing reliable binding modes. Despite these limitations, we experimentally assess the validity of MED25 interface predictions with the viral transcriptional activators Lana-1 and IE62. AlphaFold predictions also suggest the existence of a unique hydrophobic pocket for the Arabidopsis MED25 ACID domain.


Assuntos
Proteínas Imediatamente Precoces , Complexo Mediador , Humanos , Complexo Mediador/genética , Complexo Mediador/metabolismo , Ativação Transcricional , Reprodutibilidade dos Testes , Fatores de Transcrição/metabolismo , Proteínas do Envelope Viral/metabolismo , Transativadores/metabolismo , Proteínas Imediatamente Precoces/metabolismo
5.
Front Immunol ; 15: 1332440, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38375473

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the third human coronavirus to cause acute respiratory distress syndrome (ARDS) and contains four structural proteins: spike, envelope, membrane, and nucleocapsid. An increasing number of studies have demonstrated that all four structural proteins of SARS-CoV-2 are capable of causing lung injury, even without the presence of intact virus. Therefore, the topic of SARS-CoV-2 structural protein-evoked lung injury warrants more attention. In the current article, we first synopsize the structural features of SARS-CoV-2 structural proteins. Second, we discuss the mechanisms for structural protein-induced inflammatory responses in vitro. Finally, we list the findings that indicate structural proteins themselves are toxic and sufficient to induce lung injury in vivo. Recognizing mechanisms of lung injury triggered by SARS-CoV-2 structural proteins may facilitate the development of targeted modalities in treating COVID-19.


Assuntos
COVID-19 , Lesão Pulmonar , Humanos , SARS-CoV-2/metabolismo , Nucleocapsídeo/metabolismo , Proteínas do Envelope Viral/metabolismo
6.
J Med Virol ; 96(2): e29445, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38299743

RESUMO

Membrane-associated RING-CH (MARCH) family proteins were recently reported to inhibit viral replication through multiple modes. Previous work showed that human MARCH8 blocked Ebola virus (EBOV) glycoprotein (GP) maturation. Our study here demonstrates that human MARCH1 and MARCH2 share a similar pattern to MARCH8 in restricting EBOV GP-pseudotyped viral infection. Human MARCH1 and MARCH2 retain EBOV GP at the trans-Golgi network, reduce its cell surface display, and impair EBOV GP-pseudotyped virions infectivity. Furthermore, we uncover that the host proprotein convertase furin could interact with human MARCH1/2 and EBOV GP intracellularly. Importantly, the furin P domain is verified to be recognized by MARCH1/2/8, which is critical for their blocking activities. Besides, bovine MARCH2 and murine MARCH1 also impair EBOV GP proteolytic processing. Altogether, our findings confirm that MARCH1/2 proteins of different mammalian origins showed a relatively conserved feature in blocking EBOV GP cleavage, which could provide clues for subsequent MARCHs antiviral studies and may facilitate the development of novel strategies to antagonize enveloped virus infection.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola , Animais , Bovinos , Humanos , Camundongos , Linhagem Celular , Furina/metabolismo , Glicoproteínas , Mamíferos/metabolismo , Proteínas de Membrana/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Envelope Viral/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo
7.
Viruses ; 16(2)2024 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-38400027

RESUMO

Herpes simplex virus 1 (HSV-1) causes significant morbidity and death in humans worldwide. Herpes simplex virus 1 has a complex fusion mechanism that is incompletely understood. The HSV-1 strain ANG has notable fusion and entry activities that distinguish it from wild type. HSV-1 ANG virions fused with the Vero cell surface at 4 °C and also entered cells more efficiently at 15 °C, relative to wild type HSV-1 strain KOS virions, consistent with a hyperfusogenic phenotype. Understanding the molecular basis for the unique entry and fusion activities of HSV-1 strain ANG will help decipher the HSV fusion reaction and entry process. Sequencing of HSV-1 ANG genes revealed multiple changes in gB, gC, gD, gH, and gL proteins relative to wild type HSV-1 strains. The ANG UL45 gene sequence, which codes for a non-essential envelope protein, was identical to wild type KOS. HSV-1 ANG gB, gD, and gH/gL were necessary and sufficient to mediate cell-cell fusion in a virus-free reporter assay. ANG gB, when expressed with wild type KOS gD and gH/gL, increased membrane fusion, suggesting that ANG gB has hyperfusogenic cell-cell fusion activity. Replacing the KOS gD, gH, or gL with the corresponding ANG alleles did not enhance cell-cell fusion. The novel mutations in the ANG fusion and entry glycoproteins provide a platform for dissecting the cascade of interactions that culminate in HSV fusion and entry.


Assuntos
Herpesvirus Humano 1 , Humanos , Animais , Chlorocebus aethiops , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Fusão Celular , Glicoproteínas/genética , Glicoproteínas/metabolismo , Células Vero , Internalização do Vírus , Fusão de Membrana
8.
Methods Mol Biol ; 2762: 3-16, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38315356

RESUMO

Hantaviruses, are rodent-borne viruses found worldwide that are transmitted to humans through inhalation of contaminated excreta. They can cause a renal or a pulmonary syndrome, depending on the virus, and no effective treatment is currently available for either of these diseases. Hantaviral particles are covered by a protein lattice composed of two glycoproteins (Gn and Gc) that mediate adsorption to target cells and fusion with endosomal membranes, making them prime targets for neutralizing antibodies. Here we present the methodology to produce soluble recombinant glycoproteins in different conformations, either alone or as a stabilized Gn/Gc complex, using stably transfected Drosophila S2 cells.


Assuntos
Orthohantavírus , Vírus de RNA , Humanos , Animais , Drosophila melanogaster/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Glicoproteínas/metabolismo
9.
J Virol ; 98(1): e0084923, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38174935

RESUMO

Hepatitis C virus (HCV) is a member of the Flaviviridae family; however, unlike other family members, the HCV virion has an unusually high lipid content. HCV has two envelope glycoproteins, E1 and E2. E2 contributes to receptor binding, cell membrane attachment, and immune evasion. In contrast, the functions of E1 are poorly characterized due, in part, to challenges in producing the protein. This manuscript describes the expression and purification of a soluble E1 ectodomain (eE1) that is recognized by conformational, human monoclonal antibodies. eE1 forms a complex with apolipoproteins AI and AII, cholesterol, and phospholipids by recruiting high-density lipoprotein (HDL) from the extracellular media. We show that HDL binding is a function specific to eE1 and HDL hinders recognition of E1 by a neutralizing monoclonal antibody. Either low-density lipoprotein or HDL increases the production and infectivity of cell culture-produced HCV, but E1 preferentially selects HDL, influencing both viral life cycle and antibody evasion.IMPORTANCEHepatitis C virus (HCV) infection is a significant burden on human health, but vaccine candidates have yet to provide broad protection against this infection. We have developed a method to produce high quantities of soluble E1 or E2, the viral proteins located on the surface of HCV. HCV has an unusually high lipid content due to the recruitment of apolipoproteins. We found that E1 (and not E2) preferentially recruits host high-density lipoprotein (HDL) extracellularly. This recruitment of HDL by E1 prevents binding of E1 by a neutralizing antibody and furthermore prevents antibody-mediated neutralization of the virus. By comparison, low-density lipoprotein does not protect the virus from antibody-mediated neutralization. Our findings provide mechanistic insight into apolipoprotein recruitment, which may be critical for vaccine development.


Assuntos
Hepacivirus , Hepatite C , Evasão da Resposta Imune , Lipoproteínas HDL , Proteínas do Envelope Viral , Humanos , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Apolipoproteínas/metabolismo , Hepacivirus/patogenicidade , Hepatite C/imunologia , Hepatite C/virologia , Anticorpos Anti-Hepatite C/imunologia , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Proteínas do Envelope Viral/metabolismo , Células HEK293
10.
J Biomed Sci ; 31(1): 8, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38229040

RESUMO

BACKGROUND: Chikungunya virus (CHIKV) has reemerged as a major public health concern, causing chikungunya fever with increasing cases and neurological complications. METHODS: In the present study, we investigated a low-passage human isolate of the East/ Central/South African (ECSA) lineage of CHIKV strain LK(EH)CH6708, which exhibited a mix of small and large viral plaques. The small and large plaque variants were isolated and designated as CHIKV-SP and CHIKV-BP, respectively. CHIKV-SP and CHIKV-BP were characterized in vitro and in vivo to compare their virus production and virulence. Additionally, whole viral genome analysis and reverse genetics were employed to identify genomic virulence factors. RESULTS: CHIKV-SP demonstrated lower virus production in mammalian cells and attenuated virulence in a murine model. On the other hand, CHIKV-BP induced higher pro-inflammatory cytokine levels, compromised the integrity of the blood-brain barrier, and led to astrocyte infection in mouse brains. Furthermore, the CHIKV-SP variant had limited transmission potential in Aedes albopictus mosquitoes, likely due to restricted dissemination. Whole viral genome analysis revealed multiple genetic mutations in the CHIKV-SP variant, including a Glycine (G) to Arginine (R) mutation at position 55 in the viral E2 glycoprotein. Reverse genetics experiments confirmed that the E2-G55R mutation alone was sufficient to reduce virus production in vitro and virulence in mice. CONCLUSIONS: These findings highlight the attenuating effects of the E2-G55R mutation on CHIKV pathogenicity and neurovirulence and emphasize the importance of monitoring this mutation in natural infections.


Assuntos
Aedes , Vírus Chikungunya , Humanos , Camundongos , Animais , Vírus Chikungunya/genética , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Aminoácidos , Mutação , Mamíferos
11.
Nat Commun ; 15(1): 812, 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38280880

RESUMO

Langya Henipavirus (LayV) infection is an emerging zoonotic disease that has been causing respiratory symptoms in China since 2019. For virus entry, LayV's genome encodes the fusion protein F and the attachment glycoprotein G. However, the structural and functional information regarding LayV-G remains unclear. In this study, we revealed that LayV-G cannot bind to the receptors found in other HNVs, such as ephrin B2/B3, and it shows different antigenicity from HeV-G and NiV-G. Furthermore, we determined the near full-length structure of LayV-G, which displays a distinct mushroom-shaped configuration, distinguishing it from other attachment glycoproteins of HNV. The stalk and transmembrane regions resemble the stem and root of mushroom and four downward-tilted head domains as mushroom cap potentially interact with the F protein and influence membrane fusion process. Our findings enhance the understanding of emerging HNVs that cause human diseases through zoonotic transmission and provide implication for LayV related vaccine development.


Assuntos
Infecções por Henipavirus , Henipavirus , Vírus Nipah , Humanos , Microscopia Crioeletrônica , Henipavirus/genética , Glicoproteínas/metabolismo , China , Vírus Nipah/metabolismo , Internalização do Vírus , Proteínas do Envelope Viral/metabolismo
12.
Virus Res ; 340: 199283, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38043726

RESUMO

We analyzed the spike protein S1/S2 cleavage of selected strains of a prototype coronavirus, mouse hepatitis virus (MHV) by the cellular protease furin, in order to understand the structural requirements underlying the sequence selectivity of the scissile segment. The probability of cleavage of selected MHV strains was first evaluated from furin cleavage scores predicted by the ProP computer software, and then cleavage was measured experimentally with a fluorogenic peptide cleavage assay consisting of S1/S2 peptide mimics and purified furin. We found that in vitro cleavability varied across MHV strains in line with predicted results-but with the notable exception of MHV-A59, which was not cleaved despite a high score predicted for its sequence. Using the known X-Ray structure of furin in complex with a substrate-like inhibitor as an initial structural reference, we carried out molecular dynamics (MD) simulations to learn the modes of binding of the peptides in the furin active site, and the suitability of the complex for initiation of the enzymatic cleavage. We identified the 3D structural requirements of the furin active site configuration that enable bound peptides to undergo cleavage, and the way in which the various strains tested experimentally are fulfilling these requirements. We find that despite some flexibility in the organization of the peptide bound to the active site of the enzyme, the presence of a histidine at P2 of MHV-A59 fails to properly orient the sidechain of His194 of the furin catalytic triad and therefore produces a distortion that renders the peptide/complex structural configuration in the active site incompatible with requirements for cleavage initiation. The Ser/Thr in P1 of MHV-2 and MHV-S has a similar effect of distorting the conformation of the furin active site residues produced by the elimination of the canonical salt-bridge formed by arginine in P1 position. This work informs a study of coronavirus infection and pathogenesis with respect to the function of the viral spike protein, and suggests an important process of viral adaptation and evolution within the spike S1/S2 structural loop.


Assuntos
Infecções por Coronavirus , Coronavirus , Vírus da Hepatite Murina , Animais , Camundongos , Vírus da Hepatite Murina/metabolismo , Glicoproteínas de Membrana/química , Proteínas do Envelope Viral/metabolismo , Furina/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Peptídeos/metabolismo
13.
J Virol ; 98(1): e0180923, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38084956

RESUMO

The rational selection of hepatitis C virus (HCV) vaccine antigen will aid in the prevention of future chronic liver disease burden and associated healthcare costs. We have previously shown that HCV E2 glycoprotein is not highly immunogenic, and the modification of E2 reduced CD81 binding and displayed altered cytokine and protective immune responses in vitro and in a surrogate mouse model. Here, we compared the influence of a parental and a modified sE2F442NYT glycoprotein region from HCV genotype 1a for the activation of peripheral blood mononuclear cell (PBMC)-derived dendritic cells (DCs), CD4+T cells, and B cells. Modified sE2F442NYT, when incubated with DCs, induced a higher number of CD86-positive cells. The sE2F442NYT or parental sE2 encapsulated as mRNA-lipid nanoparticle (sE2F442NYT mRNA-LNP) primed DCs co-cultured with autologous CD4+T cells did not induce CD25 or forkhead box P3 expression. PBMC-derived CD4+T cells treated with sE2F442NYT exhibited enhanced signal transducer and activator of transcription (Stat)1/Stat4 phosphorylation in response to anti-CD3/CD28 stimulation in comparison to parental sE2 treatment and facilitated isotype switching in B cells, leading to the generation of a broader subclass of antibodies. Cells treated with modified sE2F442NYT displayed an increase in activated Stat3 and extracellular signal-regulated kinase (ERK). Likewise, PBMC-derived naïve B cells upon in vitro stimulation with sE2F442NYT induced an increased proliferation, Stat3 and ERK activation, and protein kinase B (Akt) suppression. Thus, the modified sE2F442NYT antigen from HCV facilitates improved DC, CD4+T, and B cell activation compared to parental sE2 to better induce a robust protective immune response, supporting its selection as an HCV candidate vaccine antigen for preclinical and clinical HCV vaccine trials.IMPORTANCEThe nature of an enhanced immune response induced by sE2F442NYT will help in the selection of a broad cross-protective antigen from hepatitis C virus genotypes, and the inclusion of relatively conserved sE1 with sE2F442NYT may further strengthen the efficacy of the candidate vaccine in evaluating it for human use.


Assuntos
Hepatite C , Vacinas contra Hepatite Viral , Animais , Humanos , Camundongos , Hepacivirus/genética , Anticorpos Anti-Hepatite C , Antígenos da Hepatite C , Leucócitos Mononucleares , RNA Mensageiro , Proteínas do Envelope Viral/metabolismo , Vacinas Virais
14.
Virology ; 589: 109914, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37931589

RESUMO

Viruses in the thogotovirus genus of the family Orthomyxoviridae are much less well-understood than influenza viruses despite documented zoonotic transmission and association with human disease. This study therefore developed a cell-cell fusion assay and three pseudotyping tools and used them to assess envelope function and cell tropism. Envelope glycoproteins of Dhori (DHOV), Thogoto (THOV), Bourbon, and Sinu viruses were all revealed to exhibit pH-dependent triggering of membrane fusion. Lentivirus vectors were robustly pseudotyped with these glycoproteins while influenza virus vectors showed pseudotyping compatibility, albeit at lower efficiencies. Replication-competent vesicular stomatitis virus expressing DHOV or THOV glycoproteins were also successfully generated. These pseudotyped viruses mediated entry into a wide range of mammalian cell lines, including human primary cells. The promiscuousness of these viruses suggests the use of a relatively ubiquitous receptor and their entry into numerous mammalian cells emphasize their high potential as veterinary and zoonotic diseases.


Assuntos
Orthomyxoviridae , Thogotovirus , Animais , Humanos , Thogotovirus/genética , Glicoproteínas/genética , Orthomyxoviridae/genética , Lentivirus/genética , Linhagem Celular , Vetores Genéticos , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Mamíferos
15.
Virology ; 590: 109968, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38141499

RESUMO

Bovine viral diarrhea virus (BVDV) is known to cause financial losses and decreased productivity in the cattle industry worldwide. Currently, there are no available antiviral treatments for effectively controlling BVDV infections in laboratories or farms. The BVDV envelope protein (E2) mediates receptor recognition on the cell surface and is required for fusion of virus and cell membranes after the endocytic uptake of the virus during the entry process. Therefore, E2 is an attractive target for the development of antiviral strategies. To identify BVDV antivirals targeting E2 function, we defined a binding site in silico located in domain IIIc at the interface between monomers in the disulfide linked dimer of E2. Employing a de novo design methodology to identify compounds with the potential to inhibit the E2 function, compound 9 emerged as a promising candidate with remarkable antiviral activity and minimal toxicity. In line with targeting of E2 function, compound 9 was found to block the virus entry into host cells. Furthermore, we demonstrated that compound 9 selectively binds to recombinant E2 in vitro. Molecular dynamics simulations (MD) allowed describing a possible interaction pattern between compound 9 and E2 and indicated that the S enantiomer of compound 9 may be responsible for the antiviral activity. Future research endeavors will focus on synthesizing enantiomerically pure compounds to further support these findings. These results highlight the usefulness of de novo design strategies to identify a novel class of BVDV inhibitors that block E2 function inhibiting virus entry into the host cell.


Assuntos
Vírus da Diarreia Viral Bovina Tipo 1 , Vírus da Diarreia Viral Bovina , Animais , Bovinos , Proteínas do Envelope Viral/metabolismo , Vírus da Diarreia Viral Bovina/genética , Vírus da Diarreia Viral Bovina Tipo 1/metabolismo , Antivirais/farmacologia
16.
J Am Chem Soc ; 146(4): 2615-2623, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38117537

RESUMO

Herpes simplex virus-1 (HSV-1) utilizes multiple viral surface glycoproteins to trigger virus entry and fusion. Among these glycoproteins, glycoprotein D (gD) functions as a receptor-binding protein, which makes it an attractive target for the development of vaccines against HSV-1 infection. Several recombinant gD subunit vaccines have been investigated in both preclinical and clinical phases with varying degrees of success. It is fundamentally critical to explore the functions of gD glycans. In light of this, we report an efficient synthetic platform to construct glycosylated gDs bearing homogeneous glycans at N94 and N121. The oligosaccharides were prepared by enzymatic synthesis and conjugated to peptidyl sectors. The glycoproteins were constructed via a combination of 7-(piperazin-1-yl)-2-(methyl)quinolinyl (PPZQ)-assisted expressed protein ligation and ß-mercapto amino acid-assisted-desulfurization strategies. Biological studies showed that synthetic gDs exhibited potent in vivo activity in mice.


Assuntos
Infecções por Herpesviridae , Herpesvirus Humano 1 , Animais , Camundongos , Herpesvirus Humano 1/metabolismo , Proteínas do Envelope Viral/metabolismo , Glicoproteínas/metabolismo , Polissacarídeos/metabolismo
17.
Nat Commun ; 14(1): 7958, 2023 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-38042814

RESUMO

Herpesviruses remain a burden for animal and human health, including the medically important varicella-zoster virus (VZV). Membrane fusion mediated by conserved core glycoproteins, the fusogen gB and the heterodimer gH-gL, enables herpesvirus cell entry. The ectodomain of gB orthologs has five domains and is proposed to transition from a prefusion to postfusion conformation but the functional relevance of the domains for this transition remains poorly defined. Here we describe structure-function studies of the VZV gB DIII central helix targeting residues 526EHV528. Critically, a H527P mutation captures gB in a prefusion conformation as determined by cryo-EM, a loss of membrane fusion in a virus free assay, and failure of recombinant VZV to spread in cell monolayers. Importantly, two predominant cryo-EM structures of gB[H527P] are identified by 3D classification and focused refinement, suggesting they represented gB conformations in transition. These studies reveal gB DIII as a critical element for herpesvirus gB fusion function.


Assuntos
Herpesvirus Humano 1 , Proteínas do Envelope Viral , Animais , Humanos , Proteínas do Envelope Viral/metabolismo , Mutagênese , Mutação , Herpesvirus Humano 3/genética , Herpesvirus Humano 1/genética , Internalização do Vírus
18.
PLoS Pathog ; 19(12): e1011848, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38055723

RESUMO

Interaction between the Ebola virus envelope glycoprotein (GP) and the endosomal membrane is an essential step during virus entry into the cell. Acidic pH and Ca2+ have been implicated in mediating the GP-membrane interaction. However, the molecular mechanism by which these environmental factors regulate the conformational changes that enable engagement of GP with the target membrane is unknown. Here, we apply fluorescence correlation spectroscopy (FCS) and single-molecule Förster resonance energy transfer (smFRET) imaging to elucidate how the acidic pH, Ca2+ and anionic phospholipids in the late endosome promote GP-membrane interaction, thereby facilitating virus entry. We find that bis(monoacylglycero)phosphate (BMP), which is specific to the late endosome, is especially critical in determining the Ca2+-dependence of the GP-membrane interaction. Molecular dynamics (MD) simulations suggested residues in GP that sense pH and induce conformational changes that make the fusion loop available for insertion into the membrane. We similarly confirm residues in the fusion loop that mediate GP's interaction with Ca2+, which likely promotes local conformational changes in the fusion loop and mediates electrostatic interactions with the anionic phospholipids. Collectively, our results provide a mechanistic understanding of how the environment of the late endosome regulates the timing and efficiency of virus entry.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola , Humanos , Ebolavirus/fisiologia , Cálcio/metabolismo , Proteínas do Envelope Viral/metabolismo , Endossomos/metabolismo , Conformação Proteica , Internalização do Vírus , Fusão de Membrana , Concentração de Íons de Hidrogênio
19.
Nat Commun ; 14(1): 7000, 2023 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-37919266

RESUMO

Viral and host glycans represent an understudied aspect of host-pathogen interactions, despite potential implications for treatment of viral infections. This is due to lack of easily accessible tools for analyzing glycan function in a meaningful context. Here we generate a glycoengineered keratinocyte library delineating human glycosylation pathways to uncover roles of specific glycans at different stages of herpes simplex virus type 1 (HSV-1) infectious cycle. We show the importance of cellular glycosaminoglycans and glycosphingolipids for HSV-1 attachment, N-glycans for entry and spread, and O-glycans for propagation. While altered virion surface structures have minimal effects on the early interactions with wild type cells, mutation of specific O-glycosylation sites affects glycoprotein surface expression and function. In conclusion, the data demonstrates the importance of specific glycans in a clinically relevant human model of HSV-1 infection and highlights the utility of genetic engineering to elucidate the roles of specific viral and cellular carbohydrate structures.


Assuntos
Herpes Simples , Herpesvirus Humano 1 , Humanos , Herpesvirus Humano 1/genética , Herpes Simples/genética , Glicoproteínas/metabolismo , Queratinócitos/metabolismo , Polissacarídeos/metabolismo , Proteínas do Envelope Viral/metabolismo
20.
J Biosci ; 482023.
Artigo em Inglês | MEDLINE | ID: mdl-38018543

RESUMO

Dengue fever cases are spiking over the last two decades. Incessant efforts are still being made to gain deeper insights on this arboviral disease and to identify bioactive antivirals. In this study, bioinformatics analysis was conducted to identify the differentially expressed genes (DEGs) in the expression profiling datasets of dengue virus serotype 2 (DENV2) patients. We found overexpressed genes in dengue patients that can interrupt cell cycle progression and phase transitions of mitosis inside the host to favour the viral replication process. These DEGs were associated with the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways such as cell cycle and DNA replication. A protein interaction network consisting of these significant pathways was also constructed using STRING. Futher, the traditional Chinese medicine (TCM) compounds from Ganoderma lucidum were screened to target DENV2 envelope protein, which was crucial for viral fusion activity. Docking, orbital energy, and toxicity prediction analysis revealed that naringenin was the best antiviral candidate. Following molecular dynamics simulations, the predicted binding energy of the protein-naringenin system using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) approach was slightly greater than the control system. It is recommended to perform in vitro inhibition of naringenin against DENV2 and use our findings to complement the experimental data obtained.


Assuntos
Vírus da Dengue , Reishi , Humanos , Vírus da Dengue/genética , Vírus da Dengue/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/metabolismo , Reishi/genética , Sorogrupo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...