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1.
PLoS Pathog ; 16(3): e1008392, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32150576

RESUMO

Coronaviruses recognize a variety of receptors using different domains of their envelope-anchored spike protein. How these diverse receptor recognition patterns affect viral entry is unknown. Mouse hepatitis coronavirus (MHV) is the only known coronavirus that uses the N-terminal domain (NTD) of its spike to recognize a protein receptor, CEACAM1a. Here we determined the cryo-EM structure of MHV spike complexed with mouse CEACAM1a. The trimeric spike contains three receptor-binding S1 heads sitting on top of a trimeric membrane-fusion S2 stalk. Three receptor molecules bind to the sides of the spike trimer, where three NTDs are located. Receptor binding induces structural changes in the spike, weakening the interactions between S1 and S2. Using protease sensitivity and negative-stain EM analyses, we further showed that after protease treatment of the spike, receptor binding facilitated the dissociation of S1 from S2, allowing S2 to transition from pre-fusion to post-fusion conformation. Together these results reveal a new role of receptor binding in MHV entry: in addition to its well-characterized role in viral attachment to host cells, receptor binding also induces the conformational change of the spike and hence the fusion of viral and host membranes. Our study provides new mechanistic insight into coronavirus entry and highlights the diverse entry mechanisms used by different viruses.


Assuntos
Antígeno Carcinoembrionário/química , Vírus da Hepatite Murina/química , Vírus da Hepatite Murina/fisiologia , Receptores Virais/química , Glicoproteína da Espícula de Coronavírus/química , Internalização do Vírus , Animais , Antígeno Carcinoembrionário/metabolismo , Antígeno Carcinoembrionário/ultraestrutura , Linhagem Celular Tumoral , Microscopia Crioeletrônica , Células HEK293 , Humanos , Fusão de Membrana , Camundongos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Conformação Proteica em alfa-Hélice , Domínios Proteicos , Multimerização Proteica , Proteólise , Receptores Virais/metabolismo , Receptores Virais/ultraestrutura , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Vírus da SARS/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/ultraestrutura , Ligação Viral
2.
Science ; 367(6483): 1260-1263, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32075877

RESUMO

The outbreak of a novel coronavirus (2019-nCoV) represents a pandemic threat that has been declared a public health emergency of international concern. The CoV spike (S) glycoprotein is a key target for vaccines, therapeutic antibodies, and diagnostics. To facilitate medical countermeasure development, we determined a 3.5-angstrom-resolution cryo-electron microscopy structure of the 2019-nCoV S trimer in the prefusion conformation. The predominant state of the trimer has one of the three receptor-binding domains (RBDs) rotated up in a receptor-accessible conformation. We also provide biophysical and structural evidence that the 2019-nCoV S protein binds angiotensin-converting enzyme 2 (ACE2) with higher affinity than does severe acute respiratory syndrome (SARS)-CoV S. Additionally, we tested several published SARS-CoV RBD-specific monoclonal antibodies and found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs. The structure of 2019-nCoV S should enable the rapid development and evaluation of medical countermeasures to address the ongoing public health crisis.


Assuntos
Betacoronavirus/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/ultraestrutura , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Betacoronavirus/metabolismo , Betacoronavirus/ultraestrutura , Reações Cruzadas , Microscopia Crioeletrônica , Processamento de Imagem Assistida por Computador , Modelos Moleculares , Peptidil Dipeptidase A/metabolismo , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Multimerização Proteica , Receptores Virais/metabolismo , Vírus da SARS/química , Vírus da SARS/imunologia , Vírus da SARS/ultraestrutura , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo
3.
Lancet ; 395(10224): 565-574, 2020 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-32007145

RESUMO

BACKGROUND: In late December, 2019, patients presenting with viral pneumonia due to an unidentified microbial agent were reported in Wuhan, China. A novel coronavirus was subsequently identified as the causative pathogen, provisionally named 2019 novel coronavirus (2019-nCoV). As of Jan 26, 2020, more than 2000 cases of 2019-nCoV infection have been confirmed, most of which involved people living in or visiting Wuhan, and human-to-human transmission has been confirmed. METHODS: We did next-generation sequencing of samples from bronchoalveolar lavage fluid and cultured isolates from nine inpatients, eight of whom had visited the Huanan seafood market in Wuhan. Complete and partial 2019-nCoV genome sequences were obtained from these individuals. Viral contigs were connected using Sanger sequencing to obtain the full-length genomes, with the terminal regions determined by rapid amplification of cDNA ends. Phylogenetic analysis of these 2019-nCoV genomes and those of other coronaviruses was used to determine the evolutionary history of the virus and help infer its likely origin. Homology modelling was done to explore the likely receptor-binding properties of the virus. FINDINGS: The ten genome sequences of 2019-nCoV obtained from the nine patients were extremely similar, exhibiting more than 99·98% sequence identity. Notably, 2019-nCoV was closely related (with 88% identity) to two bat-derived severe acute respiratory syndrome (SARS)-like coronaviruses, bat-SL-CoVZC45 and bat-SL-CoVZXC21, collected in 2018 in Zhoushan, eastern China, but were more distant from SARS-CoV (about 79%) and MERS-CoV (about 50%). Phylogenetic analysis revealed that 2019-nCoV fell within the subgenus Sarbecovirus of the genus Betacoronavirus, with a relatively long branch length to its closest relatives bat-SL-CoVZC45 and bat-SL-CoVZXC21, and was genetically distinct from SARS-CoV. Notably, homology modelling revealed that 2019-nCoV had a similar receptor-binding domain structure to that of SARS-CoV, despite amino acid variation at some key residues. INTERPRETATION: 2019-nCoV is sufficiently divergent from SARS-CoV to be considered a new human-infecting betacoronavirus. Although our phylogenetic analysis suggests that bats might be the original host of this virus, an animal sold at the seafood market in Wuhan might represent an intermediate host facilitating the emergence of the virus in humans. Importantly, structural analysis suggests that 2019-nCoV might be able to bind to the angiotensin-converting enzyme 2 receptor in humans. The future evolution, adaptation, and spread of this virus warrant urgent investigation. FUNDING: National Key Research and Development Program of China, National Major Project for Control and Prevention of Infectious Disease in China, Chinese Academy of Sciences, Shandong First Medical University.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Genoma Viral , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Receptores Virais/metabolismo , Betacoronavirus/metabolismo , Líquido da Lavagem Broncoalveolar/virologia , China/epidemiologia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , DNA Viral/genética , Reservatórios de Doenças/virologia , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Filogenia , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Alinhamento de Sequência
4.
J Agric Food Chem ; 68(5): 1207-1212, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31755264

RESUMO

Human noroviruses (HuNoVs) are among the main pathogens causing acute nonbacterial gastroenteritis. Histo-blood group antigens (HBGAs) are widely accepted receptors for HuNoV specific binding. HBGA-like substances in produce are also considered as the critical ligands for capture of HuNoVs. However, the composition of viral ligands from food substrates remains unknown. In this study, an oligosaccharide (H2N2F2) was captured and isolated from romaine lettuce extract by a bacterial surface display system. Using electrospray ionization mass spectrometry and tandem mass spectrometry, it was shown that H2N2F2 was most likely to be a chimera of type A, H, and Lewis a HBGAs. The composition was consistent with our ELISA results using a panel of monoclonal antibodies against HBGAs. Our results revealed a possible interaction mechanism between HuNoVs and romaine lettuce. Better understanding of the interaction of HuNoVs with easily contaminated produce will ultimately aid in the control of and reduction in disease outbreaks.


Assuntos
Antígenos de Plantas/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Alface/virologia , Norovirus/fisiologia , Receptores Virais/metabolismo , Ligação Viral , Antígenos de Plantas/química , Antígenos de Plantas/genética , Antígenos de Grupos Sanguíneos/química , Antígenos de Grupos Sanguíneos/genética , Infecções por Caliciviridae/genética , Infecções por Caliciviridae/metabolismo , Infecções por Caliciviridae/virologia , Humanos , Alface/química , Alface/genética , Alface/metabolismo , Espectrometria de Massas , Norovirus/genética , Oligossacarídeos/química , Oligossacarídeos/genética , Oligossacarídeos/metabolismo , Ligação Proteica , Receptores Virais/química , Receptores Virais/genética
5.
Cancer Sci ; 111(2): 383-394, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830330

RESUMO

Patients with triple-negative breast cancer (TNBC) lack molecular targets and have an unfavorable outcome. CD155 is overexpressed in human cancers, but whether it plays a role in TNBC is unexplored. Here we found that CD155 was enriched in both TNBC cell lines and tumor tissues. High CD155 expression was related to poor prognosis of breast cancer patients. CD155 was associated with a mesenchymal phenotype. CD155 knockdown induced a mesenchymal-epithelial transition in TNBC cells, and suppressed TNBC cell migration, invasion and metastasis in vitro and in vivo. Mechanistically, CD155 cross-talked with oncogenic IL-6/Stat3 and TGF-ß/Smad3 pathways. Moreover, CD155 knockdown inhibited TNBC cell growth and survival. Taken together, these data indicate that CD155 contributes to the aggressive behavior of TNBC; targeting CD155 may be beneficial to these patients.


Assuntos
Receptores Virais/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Regulação para Cima , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Células MCF-7 , Metástase Neoplásica , Transplante de Neoplasias , Prognóstico , Receptores Virais/genética , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo
6.
BMC Bioinformatics ; 20(Suppl 23): 651, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31881820

RESUMO

BACKGROUND: Viral infectious diseases are the serious threat for human health. The receptor-binding is the first step for the viral infection of hosts. To more effectively treat human viral infectious diseases, the hidden virus-receptor interactions must be discovered. However, current computational methods for predicting virus-receptor interactions are limited. RESULT: In this study, we propose a new computational method (IILLS) to predict virus-receptor interactions based on Initial Interaction scores method via the neighbors and the Laplacian regularized Least Square algorithm. IILLS integrates the known virus-receptor interactions and amino acid sequences of receptors. The similarity of viruses is calculated by the Gaussian Interaction Profile (GIP) kernel. On the other hand, we also compute the receptor GIP similarity and the receptor sequence similarity. Then the sequence similarity is used as the final similarity of receptors according to the prediction results. The 10-fold cross validation (10CV) and leave one out cross validation (LOOCV) are used to assess the prediction performance of our method. We also compare our method with other three competing methods (BRWH, LapRLS, CMF). CONLUSION: The experiment results show that IILLS achieves the AUC values of 0.8675 and 0.9061 with the 10-fold cross validation and leave-one-out cross validation (LOOCV), respectively, which illustrates that IILLS is superior to the competing methods. In addition, the case studies also further indicate that the IILLS method is effective for the virus-receptor interaction prediction.


Assuntos
Receptores Virais/metabolismo , Software , Aprendizado de Máquina Supervisionado , Vírus/metabolismo , Algoritmos , Humanos , Análise dos Mínimos Quadrados , Curva ROC , Reprodutibilidade dos Testes
7.
PLoS Pathog ; 15(12): e1008193, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856258

RESUMO

Tailed bacteriophages (phages) are one of the most abundant life forms on Earth. They encode highly efficient molecular machines to infect bacteria, but the initial interactions between a phage and a bacterium that then lead to irreversible virus attachment and infection are poorly understood. This information is critically needed to engineer machines with novel host specificities in order to combat antibiotic resistance, a major threat to global health today. The tailed phage T4 encodes a specialized device for this purpose, the long tail fiber (LTF), which allows the virus to move on the bacterial surface and find a suitable site for infection. Consequently, the infection efficiency of phage T4 is one of the highest, reaching the theoretical value of 1. Although the atomic structure of the tip of the LTF has been determined, its functional architecture and how interactions with two structurally very different Escherichia coli receptor molecules, lipopolysaccharide (LPS) and outer membrane protein C (OmpC), contribute to virus movement remained unknown. Here, by developing direct receptor binding assays, extensive mutational and biochemical analyses, and structural modeling, we discovered that the ball-shaped tip of the LTF, a trimer of gene product 37, consists of three sets of symmetrically alternating binding sites for LPS and/or OmpC. Our studies implicate reversible and dynamic interactions between these sites and the receptors. We speculate that the LTF might function as a "molecular pivot" allowing the virus to "walk" on the bacterium by adjusting the angle or position of interaction of the six LTFs attached to the six-fold symmetric baseplate.


Assuntos
Bacteriófago T4/genética , Bacteriófago T4/metabolismo , Bacteriófago T4/ultraestrutura , Escherichia coli/virologia , Ligação Viral , Animais , Camundongos , Porinas/metabolismo , Receptores Virais/metabolismo
8.
Nat Commun ; 10(1): 4460, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575869

RESUMO

Viral infection is an intricate process that requires the concerted action of both viral and host cell components. Entry of viruses into cells is initiated by interactions between viral proteins and their cell surface receptors. Despite recent progress, the molecular mechanisms underlying the multistep reovirus entry process are poorly understood. Using atomic force microscopy, we investigated how the reovirus σ1 attachment protein binds to both α-linked sialic acid (α-SA) and JAM-A cell-surface receptors. We discovered that initial σ1 binding to α-SA favors a strong multivalent anchorage to JAM-A. The enhanced JAM-A binding by virions following α-SA engagement is comparable to JAM-A binding by infectious subvirion particles (ISVPs) in the absence of α-SA. Since ISVPs have an extended σ1 conformer, this finding suggests that α-SA binding triggers a conformational change in σ1. These results provide new insights into the function of viral attachment proteins in the initiation of infection and open new avenues for the use of reoviruses as oncolytic agents.


Assuntos
Polissacarídeos/metabolismo , Polissacarídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Receptores Virais/efeitos dos fármacos , Receptores Virais/metabolismo , Reoviridae/efeitos dos fármacos , Proteínas Virais/metabolismo , Ligação Viral/efeitos dos fármacos , Animais , Células CHO , Moléculas de Adesão Celular , Linhagem Celular , Cricetulus , Interações Hospedeiro-Patógeno , Modelos Moleculares , Ligação Proteica/fisiologia , Receptores de Superfície Celular/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Proteínas Virais/química , Proteínas Virais/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos
9.
Nature ; 574(7779): 549-552, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31645729

RESUMO

About half of all bacteria carry genes for CRISPR-Cas adaptive immune systems1, which provide immunological memory by inserting short DNA sequences from phage and other parasitic DNA elements into CRISPR loci on the host genome2. Whereas CRISPR loci evolve rapidly in natural environments3,4, bacterial species typically evolve phage resistance by the mutation or loss of phage receptors under laboratory conditions5,6. Here we report how this discrepancy may in part be explained by differences in the biotic complexity of in vitro and natural environments7,8. Specifically, by using the opportunistic pathogen Pseudomonas aeruginosa and its phage DMS3vir, we show that coexistence with other human pathogens amplifies the fitness trade-offs associated with the mutation of phage receptors, and therefore tips the balance in favour of the evolution of CRISPR-based resistance. We also demonstrate that this has important knock-on effects for the virulence of P. aeruginosa, which became attenuated only if the bacteria evolved surface-based resistance. Our data reveal that the biotic complexity of microbial communities in natural environments is an important driver of the evolution of CRISPR-Cas adaptive immunity, with key implications for bacterial fitness and virulence.


Assuntos
Bacteriófagos/genética , Bacteriófagos/imunologia , Biodiversidade , Sistemas CRISPR-Cas/genética , Evolução Molecular , Pseudomonas aeruginosa/imunologia , Pseudomonas aeruginosa/virologia , Bacteriófagos/patogenicidade , Sistemas CRISPR-Cas/imunologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Receptores Virais/metabolismo
10.
Emerg Microbes Infect ; 8(1): 1280-1290, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31495283

RESUMO

The H3N2 influenza viruses became widespread in humans during the 1968 H3N2 pandemic and have been a major cause of influenza epidemics ever since. Different lineages of H3N2 influenza viruses are also commonly found in animals. If a different lineage of H3N2 virus jumps to humans, a human influenza pandemic could occur with devastating consequences. Here, we studied the genetics, receptor-binding properties, and replication and transmission in mammals of 15 H3N2 avian influenza viruses detected in live poultry markets in China. We found that the H3N2 avian influenza viruses are complicated reassortants with distinct replication phenotypes in mice. Five viruses replicated efficiently in mice and bound to both human-type and avian-type receptors. These viruses transmitted efficiently to direct-contact guinea pigs, and three of them also transmitted among guinea pigs and ferrets via respiratory droplets. Moreover, ferret antiserum induced by human H3N2 viruses did not react with any of the H3N2 avian influenza viruses. Our study demonstrates that the H3N2 avian influenza viruses pose a clear threat to human health and emphasizes the need for continued surveillance and evaluation of the H3N2 influenza viruses circulating in nature.


Assuntos
Transmissão de Doença Infecciosa , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/fisiologia , Influenza Aviária/virologia , Aves Domésticas/virologia , Ligação Viral , Animais , China , Modelos Animais de Doenças , Furões , Cobaias , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Camundongos Endogâmicos BALB C , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Vírus Reordenados/fisiologia , Receptores Virais/metabolismo , Doenças dos Roedores/virologia , Replicação Viral
11.
Adv Virus Res ; 104: 147-183, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31439148

RESUMO

Rhabdoviruses are enveloped viruses with a negative-sense single strand RNA genome and are widespread among a great variety of organisms. In their membrane, they have a single glycoprotein (G) that mediates both virus attachment to cellular receptors and fusion between viral and endosomal membranes allowing viral genome release in the cytoplasm. We present structural and cellular aspects of Rhabdovirus entry into their host cell with a focus on vesicular stomatitis virus (VSV) and rabies virus (RABV) for which the early events of the viral cycle have been extensively studied. Recent data have shown that the only VSV receptors are the members of the LDL-R family. This is in contrast with RABV for which multiple receptors belonging to unrelated families have been identified. Despite having different receptors, after attachment, rhabdovirus internalization occurs through clathrin-mediated endocytosis (CME) in an actin-dependent manner. There are still debates about the exact endocytic pathway of VSV in the cell and on RABV transport in the neuronal axon. In any case, fusion is triggered in the endosomal vesicle via a low-pH induced structural rearrangement of G from its pre- to its postfusion conformation. Vesiculovirus G is one of the best characterized fusion glycoproteins as the previously reported crystal structures of the pre- and postfusion states have been recently completed by those of intermediates during the structural transition. Understanding the entry pathway of rhabdoviruses may have strong impact in biotechnologies as, for example, VSV G is used for pseudotyping lentiviruses to promote efficient transduction, and VSV is a promising oncolytic virus.


Assuntos
Interações Hospedeiro-Patógeno , Vírus da Raiva/fisiologia , Vesiculovirus/fisiologia , Ligação Viral , Internalização do Vírus , Endocitose , Glicoproteínas/metabolismo , Receptores Virais/metabolismo , Proteínas do Envelope Viral/metabolismo
12.
Adv Virus Res ; 104: 283-312, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31439151

RESUMO

In this chapter, we present an overview on betaherpesvirus entry, with a focus on human cytomegalovirus, human herpesvirus 6A and human herpesvirus 6B. Human cytomegalovirus (HCMV) is a complex human pathogen with a genome of 235kb encoding more than 200 genes. It infects a broad range of cell types by switching its viral ligand on the virion, using the trimer gH/gL/gO for infection of fibroblasts and the pentamer gH/gL/UL128/UL130/UL131 for infection of other cells such as epithelial and endothelial cells, leading to membrane fusion mediated by the fusion protein gB. Adding to this scenario, however, accumulating data reveal the actual complexity in the viral entry process of HCMV with an intricate interplay among viral and host factors. Key novel findings include the identification of entry receptors platelet-derived growth factor-α receptor (PDGFRα) and Netropilin-2 (Nrp2) for trimer and pentamer, respectively, the determination of atomic structures of the fusion protein gB and the pentamer, and the in situ visualization of the state and arrangement of functional glycoproteins on virion. This is covered in the first part of this review. The second part focusses on HHV-6 which is a T lymphotropic virus categorized as two distinct virus species, HHV-6A and HHV-6B based on differences in epidemiological, biological, and immunological aspects, although homology of their entire genome sequences is nearly 90%. HHV-6B is a causative agent of exanthema subitum (ES), but the role of HHV-6A is unknown. HHV-6B reactivation occasionally causes encephalitis in patients with hematopoietic stem cell transplant. The HHV-6 specific envelope glycoprotein complex, gH/gL/gQ1/gQ2 is a viral ligand for the entry receptor. Recently, each virus has been found to recognize a different cellular receptor, CD46 for HHV 6A amd CD134 for HHV 6B. These findings show that distinct receptor recognition differing between both viruses could explain their different pathogenesis.


Assuntos
Citomegalovirus/fisiologia , Herpesvirus Humano 6/fisiologia , Internalização do Vírus , Células Endoteliais/virologia , Células Epiteliais/virologia , Fibroblastos/virologia , Glicoproteínas/metabolismo , Humanos , Proteína Cofatora de Membrana/metabolismo , Neuropilina-2/metabolismo , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Receptores OX40/metabolismo , Receptores Virais/metabolismo , Linfócitos T/virologia , Proteínas do Envelope Viral/metabolismo
13.
Adv Virus Res ; 104: 313-343, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31439152

RESUMO

The prototypical human γ-herpesviruses Epstein-Barr virus (EBV) and Kaposi Sarcoma-associated herpesvirus (KSHV) are involved in the development of malignancies. Like all herpesviruses, they share the establishment of latency, the typical architecture, and the conserved fusion machinery to initiate infection. The fusion machinery reflects virus-specific adaptations due to the requirements of the respective herpesvirus. For example, EBV evolved a tropism switch involving either the B- or epithelial cell-tropism complexes to activate fusion driven by gB. Most of the EBV entry proteins and their cellular receptors have been crystallized providing molecular details of the initial steps of infection. For KSHV, a variety of entry and binding receptors has also been reported but the mechanism how receptor binding activates gB-driven fusion is not as well understood as that for EBV. However, the downstream signaling pathways that promote the early steps of KSHV entry are well described. This review summarizes the current knowledge of the key players involved in EBV and KSHV entry and the cell-type specific mechanisms that allow infection of a wide variety of cell types.


Assuntos
Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/fisiologia , Internalização do Vírus , Linfócitos B/virologia , Células Epiteliais/virologia , Humanos , Ligação Proteica , Receptores Virais/metabolismo , Proteínas Virais/metabolismo
14.
Adv Virus Res ; 104: 185-224, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31439149

RESUMO

Hantaviruses are important zoonotic pathogens of public health importance that are found on all continents except Antarctica and are associated with hemorrhagic fever with renal syndrome (HFRS) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. Despite the significant disease burden they cause, no FDA-approved specific therapeutics or vaccines exist against these lethal viruses. The lack of available interventions is largely due to an incomplete understanding of hantavirus pathogenesis and molecular mechanisms of virus replication, including cellular entry. Hantavirus Gn/Gc glycoproteins are the only viral proteins exposed on the surface of virions and are necessary and sufficient to orchestrate virus attachment and entry. In vitro studies have implicated integrins (ß1-3), DAF/CD55, and gC1qR as candidate receptors that mediate viral attachment for both Old World and New World hantaviruses. Recently, protocadherin-1 (PCDH1) was demonstrated as a requirement for cellular attachment and entry of New World hantaviruses in vitro and lethal HPS in vivo, making it the first clade-specific host factor to be identified. Attachment of hantavirus particles to cellular receptors induces their internalization by clathrin-mediated, dynamin-independent, or macropinocytosis-like mechanisms, followed by particle trafficking to an endosomal compartment where the fusion of viral and endosomal membranes can occur. Following membrane fusion, which requires cholesterol and acid pH, viral nucleocapsids escape into the cytoplasm and launch genome replication. In this review, we discuss the current mechanistic understanding of hantavirus entry, highlight gaps in our existing knowledge, and suggest areas for future inquiry.


Assuntos
Hantavirus/fisiologia , Interações Hospedeiro-Patógeno , Internalização do Vírus , Pesquisa Biomédica/tendências , Ligação Proteica , Receptores Virais/metabolismo , Proteínas do Envelope Viral/metabolismo , Ligação Viral
15.
Immunobiology ; 224(5): 605-613, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31402149

RESUMO

PURPOSE: The delayed rejection caused by strong cell-mediated innate and adaptive xenogeneic immune responses continues to be a major obstacle. Therefore, suppressing macrophage function could be effective in avoiding this type of rejection. In this study, the suppression of T-cell immunoglobulin and ITIM domain (TIGIT) function against macrophage-mediated xenogeneic rejection was investigated. MATERIAL AND METHODS: Naïve porcine aortic endothelial cell (PAEC) and PAEC transfectant with TIGIT (PAEC/TIGIT) were co-cultured with M1 macrophages, and the degree of cytotoxicity was determined by a counting beads assay. The anti/pro-inflammatory gene expression was determined by RT-PCR and the phosphorylated SHP-1 in the macrophages after co-culturing with PAEC or PAEC/TIGIT was evaluated by western blotting. RESULTS: CD155 was expressed at essentially equal levels on both M1 and M2 macrophages, whereas TIGIT was highly expressed on M2 macrophages but not in M1 macrophages. TIGIT on PAEC significantly reduced the cytotoxicity of M1 macrophages but no significant suppression of phagocytosis was detected. TIGIT also caused a decrease in the expression of pro-inflammatory cytokines, namely TNFα, IL-1ß and IL-12 in M1 macrophages. Furthermore, PAEC/TIGIT caused a significant increase in phosphorylated SHP-1 in M1 macrophages compared to PAEC. CONCLUSION: The findings of this study indicate that TIGIT suppresses xenogeneic M1 macrophage-induced cytotoxicity, probably at least in part, via the phosphorylation of SHP-1. In addition, the reduced expression of some pro-inflammatory cytokines, namely TNFα, IL-1ß and IL-12, was observed in M1 macrophages that had been cultured with PAEC/TIGIT.


Assuntos
Aorta/metabolismo , Citotoxicidade Imunológica , Células Endoteliais/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Receptores Imunológicos/genética , Imunidade Adaptativa , Animais , Aorta/imunologia , Células Cultivadas , Citocinas/metabolismo , Citotoxicidade Imunológica/genética , Células Endoteliais/imunologia , Expressão Gênica , Rejeição de Enxerto/genética , Rejeição de Enxerto/imunologia , Xenoenxertos , Humanos , Imunidade Inata , Mediadores da Inflamação/metabolismo , Modelos Biológicos , Fagocitose/genética , Fagocitose/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Receptores Imunológicos/metabolismo , Receptores Virais/genética , Receptores Virais/metabolismo , Transdução de Sinais , Suínos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
16.
Nat Commun ; 10(1): 3171, 2019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31320648

RESUMO

Enteroviruses are a major cause of human disease. Adipose-specific phospholipase A2 (PLA2G16) was recently identified as a pan-enterovirus host factor and potential drug target. In this study, we identify a possible mechanism of PLA2G16 evasion by employing a dual glycan receptor-binding enterovirus D68 (EV-D68) strain. We previously showed that this strain does not strictly require the canonical EV-D68 receptor sialic acid. Here, we employ a haploid screen to identify sulfated glycosaminoglycans (sGAGs) as its second glycan receptor. Remarkably, engagement of sGAGs enables this virus to bypass PLA2G16. Using cryo-EM analysis, we reveal that, in contrast to sialic acid, sGAGs stimulate genome release from virions via structural changes that enlarge the putative openings for genome egress. Together, we describe an enterovirus that can bypass PLA2G16 and identify additional virion destabilization as a potential mechanism to circumvent PLA2G16.


Assuntos
Enterovirus Humano D/crescimento & desenvolvimento , Glicosaminoglicanos/metabolismo , Fosfolipases A2 Independentes de Cálcio/metabolismo , Receptores Virais/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Internalização do Vírus , Desenvelopamento do Vírus/fisiologia , Linhagem Celular Tumoral , Microscopia Crioeletrônica , Enterovirus Humano D/genética , Infecções por Enterovirus/patologia , Genoma Viral/genética , Células HEK293 , Células HeLa , Humanos , Ácido N-Acetilneuramínico/metabolismo
17.
Artif Cells Nanomed Biotechnol ; 47(1): 3021-3028, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31334674

RESUMO

Identification of specific cell markers is crucial for recognizing functionally healthy nucleus pulposus (NP) cells. The objective of this study was to investigate the role of CD24 expression in adult human NP cells. Cells were retrieved from NP tissues of 20 patients (aged 17-44) operated on for lumbar disc herniation. Based on CD24 expression, NP cells were separated by sorting and then used to examine phenotypic behavior, the effects of culture conditions and cellular senescence pathway related proteins. CD24 expression was positive in 35.5 ± 3.7% (range 9.1-65.2%) of NP cells. Consistently, normoxic expansion and serial passages in monolayers decreased percentage positivity for CD24 in NP cells. CD24- NP cells showed a markedly decreased GSK-3ß activity and increased mitogen-activated protein kinase phosphorylation accompanying by an increased ß-catenin expression. Higher levels of matrix metalloproteinases, as well as lower levels of ACAN and COL2 in CD24- cells, indicated the breakdown and reduced the formation of key extracellular matrix components. CD24+ NP cells presented a more favorable phenotype while CD24- cells showed a more prominent cellular senescence fate. CD24 in NP cells may be a surrogate marker of healthy cells, in the cell-based therapeutic treatment of degenerative disc disorders.


Assuntos
Antígeno CD24/genética , Antígeno CD24/metabolismo , Senescência Celular , Regulação da Expressão Gênica , Núcleo Pulposo/citologia , Fenótipo , Adolescente , Adulto , Feminino , Proteínas Fetais/metabolismo , Humanos , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Virais/metabolismo , Proteínas com Domínio T/metabolismo , Adulto Jovem
18.
PLoS Pathog ; 15(7): e1007918, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31329640

RESUMO

T-follicular helper (Tfh) cells, co-expressing PD-1 and TIGIT, serve as a major cell reservoir for HIV-1 and are responsible for active and persistent HIV-1 transcription after prolonged antiretroviral therapy (ART). However, the precise mechanisms regulating HIV-1 transcription in lymph nodes (LNs) remain unclear. In the present study, we investigated the potential role of immune checkpoint (IC)/IC-Ligand (IC-L) interactions on HIV-1 transcription in LN-microenvironment. We show that PD-L1 (PD-1-ligand) and CD155 (TIGIT-ligand) are predominantly co-expressed on LN migratory (CD1chighCCR7+CD127+) dendritic cells (DCs), that locate predominantly in extra-follicular areas in ART treated individuals. We demonstrate that TCR-mediated HIV production is suppressed in vitro in the presence of recombinant PD-L1 or CD155 and, more importantly, when LN migratory DCs are co-cultured with PD-1+/Tfh cells. These results indicate that LN migratory DCs expressing IC-Ls may more efficiently restrict HIV-1 transcription in the extra-follicular areas and explain the persistence of HIV transcription in PD-1+/Tfh cells after prolonged ART within germinal centers.


Assuntos
Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/genética , HIV-1/patogenicidade , Receptor de Morte Celular Programada 1/metabolismo , Fármacos Anti-HIV/uso terapêutico , Anticorpos Monoclonais Humanizados/administração & dosagem , Movimento Celular/imunologia , Microambiente Celular/imunologia , Técnicas de Cocultura , Células Dendríticas/imunologia , Células Dendríticas/virologia , Centro Germinativo/imunologia , Centro Germinativo/virologia , Infecções por HIV/tratamento farmacológico , HIV-1/imunologia , Interações entre Hospedeiro e Microrganismos/imunologia , Humanos , Técnicas In Vitro , Linfonodos/imunologia , Linfonodos/virologia , Proteína 2 Ligante de Morte Celular Programada 1/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptores Imunológicos/metabolismo , Receptores Virais/metabolismo , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/virologia , Transcrição Genética , Virulência
19.
PLoS Negl Trop Dis ; 13(6): e0006983, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31242184

RESUMO

BACKGROUND: T cell immunoglobulin mucin domain-1 (TIM-1) is a phosphatidylserine (PS) receptor, mediating filovirus entry into cells through interactions with PS on virions. TIM-1 expression has been implicated in Ebola virus (EBOV) pathogenesis; however, it remains unclear whether this is due to TIM-1 serving as a filovirus receptor in vivo or, as others have suggested, TIM-1 induces a cytokine storm elicited by T cell/virion interactions. Here, we use a BSL2 model virus that expresses EBOV glycoprotein to demonstrate the importance of TIM-1 as a virus receptor late during in vivo infection. METHODOLOGY/PRINCIPAL FINDINGS: Infectious, GFP-expressing recombinant vesicular stomatitis virus encoding either full length EBOV glycoprotein (EBOV GP/rVSV) or mucin domain deleted EBOV glycoprotein (EBOV GPΔO/rVSV) was used to assess the role of TIM-1 during in vivo infection. GFP-expressing rVSV encoding its native glycoprotein G (G/rVSV) served as a control. TIM-1-sufficient or TIM-1-deficient BALB/c interferon α/ß receptor-/- mice were challenged with these viruses. While G/rVSV caused profound morbidity and mortality in both mouse strains, TIM-1-deficient mice had significantly better survival than TIM-1-expressing mice following EBOV GP/rVSV or EBOV GPΔO/rVSV challenge. EBOV GP/rVSV or EBOV GPΔO/rVSV in spleen of infected animals was high and unaffected by expression of TIM-1. However, infectious virus in serum, liver, kidney and adrenal gland was reduced late in infection in the TIM-1-deficient mice, suggesting that virus entry via this receptor contributes to virus load. Consistent with higher virus loads, proinflammatory chemokines trended higher in organs from infected TIM-1-sufficient mice compared to the TIM-1-deficient mice, but proinflammatory cytokines were more modestly affected. To assess the role of T cells in EBOV GP/rVSV pathogenesis, T cells were depleted in TIM-1-sufficient and -deficient mice and the mice were challenged with virus. Depletion of T cells did not alter the pathogenic consequences of virus infection. CONCLUSIONS: Our studies provide evidence that at late times during EBOV GP/rVSV infection, TIM-1 increased virus load and associated mortality, consistent with an important role of this receptor in virus entry. This work suggests that inhibitors which block TIM-1/virus interaction may serve as effective antivirals, reducing virus load at late times during EBOV infection.


Assuntos
Ebolavirus/fisiologia , Doença pelo Vírus Ebola/virologia , Receptor Celular 1 do Vírus da Hepatite A/metabolismo , Receptores Virais/metabolismo , Internalização do Vírus , Animais , Ebolavirus/genética , Feminino , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética , Receptor Celular 1 do Vírus da Hepatite A/deficiência , Camundongos Endogâmicos BALB C , Camundongos Knockout , Receptores Virais/deficiência , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Genética Reversa , Vesiculovirus/genética , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo
20.
Appl Microbiol Biotechnol ; 103(16): 6809-6823, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31236618

RESUMO

Following the emergence of antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP), phage therapy has attracted significant attention as an alternative to antibiotic treatment. Bacteriophages belonging to kayvirus (previously known as Twort-like phages) have broad host range and are strictly lytic in Staphylococcus spp. Previous work revealed that kayvirus ɸSA039 has a host-recognition mechanism distinct from those of other known kayviruses: most of kayviruses use the backbone of wall teichoic acid (WTA) as their receptor; by contrast, ɸSA039 uses the ß-N-acetylglucosamine (ß-GlcNAc) residue in WTA. In this study, we found that ɸSA039 could switch its receptor to be able to infect S. aureus lacking the ß-GlcNAc residue by acquiring a spontaneous mutation in open reading frame (ORF) 100 and ORF102. Moreover, ɸSA039 could infect S. pseudintermedius, which has a different WTA structure than S. aureus. By comparison, with newly isolated S. pseudintermedius-specific phage (SP phages), we determined that glycosylation in WTA of S. pseudintermedius is essential for adsorption of SP phages, but not ɸSA039. Finally, we describe a novel strategy of S. aureus which protects the bacteria from infection of SP phages. Notably, glycosylation of ribitol phosphate (RboP) WTA by TarM or/and TarS prevents infection of S. aureus by SP phages. These findings could help to establish a new strategy for the treatment of S. aureus and S. pseudintermedius infection, as well as provide valuable insights into the biology of phage-host interactions.


Assuntos
Fagos de Staphylococcus/fisiologia , Staphylococcus/virologia , Interferência Viral , Ligação Viral , Receptores Virais/metabolismo , Ácidos Teicoicos/metabolismo
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