RESUMO
Since WHO has declared the COVID-19 outbreak a global pandemic, nearly seven million deaths have been reported. This efficient spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is facilitated by the ability of the spike glycoprotein to bind multiple cell membrane receptors. Although ACE2 is identified as the main receptor for SARS-CoV-2, other receptors could play a role in viral entry. Among others, C-type lectins such as DC-SIGN are identified as efficient trans-receptor for SARS-CoV-2 infection, so the use of glycomimetics to inhibit the infection through the DC-SIGN blockade is an encouraging approach. In this regard, multivalent nanostructures based on glycosylated [60]fullerenes linked to a central porphyrin scaffold have been designed and tested against DC-SIGN-mediated SARS-CoV-2 infection. First results show an outstanding inhibition of the trans-infection up to 90%. In addition, a deeper understanding of nanostructure-receptor binding is achieved through microscopy techniques, high-resolution NMR experiments, Quartz Crystal Microbalance experiments, and molecular dynamic simulations.
Assuntos
Moléculas de Adesão Celular , Fulerenos , Lectinas Tipo C , Porfirinas , Receptores de Superfície Celular , SARS-CoV-2 , Humanos , Moléculas de Adesão Celular/metabolismo , Moléculas de Adesão Celular/antagonistas & inibidores , COVID-19/virologia , Tratamento Farmacológico da COVID-19 , Fulerenos/química , Fulerenos/farmacologia , Lectinas Tipo C/metabolismo , Lectinas Tipo C/antagonistas & inibidores , Simulação de Dinâmica Molecular , Porfirinas/química , Porfirinas/farmacologia , Ligação Proteica , Receptores de Superfície Celular/metabolismo , Receptores de Superfície Celular/antagonistas & inibidores , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/químicaRESUMO
African swine fever virus (ASFV) infectious cycle starts with the viral adsorption and entry into the host cell. Then, the virus is internalized via clathrin/dynamin mediated endocytosis and macropinocytosis. Similar to other viruses, ASF virion is then internalized and incorporated into the endocytic pathway. While the endosomal maturation entails luminal acidification, the decrease in pH acts on the multilayer structure of the virion dissolving the outer capsid. Upon decapsidation, the inner viral membrane is exposed to interact with the limiting membrane of the late endosome for fusion. Viral fusion is then necessary for the egress of incoming virions from endosomes into the cytoplasm, however this remains an intriguing and yet essential process for infection, specifically for the egress of viral nucleic acid into the cytoplasm for replication. ASFV proteins E248R and E199L, located at the exposed inner viral membrane, might be implicated in the fusion step. An interaction between these viral proteins and cellular endosomal proteins such as the Niemann-Pick C type 1 (NPC1) and lysosomal membrane proteins (Lamp-1 and -2) was shown. Furthermore, the silencing of these proteins impaired ASFV infection. It was also observed that NPC1 knock-out cells using CRISPR jeopardized ASFV infection and that the progression and endosomal exit of viral cores was arrested within endosomes at viral entry. These results suggest that the interactions of ASFV proteins with some endosomal proteins might be important for the membrane fusion step. In addition to this, reductions on ASFV infectivity and replication in NPC1 KO cells were accompanied by fewer and smaller viral factories. Our findings pave the way to understanding the role of proteins of the endosomal membrane in ASFV infection.
Assuntos
Vírus da Febre Suína Africana/patogenicidade , Febre Suína Africana/virologia , Endossomos/virologia , Interações Hospedeiro-Patógeno/fisiologia , Proteínas Virais/metabolismo , Vírus da Febre Suína Africana/metabolismo , Animais , Chlorocebus aethiops , Endossomos/metabolismo , Células HEK293 , Humanos , Suínos , Células VeroRESUMO
The efficient spread of SARS-CoV-2 resulted in a unique pandemic in modern history. Despite early identification of ACE2 as the receptor for viral spike protein, much remains to be understood about the molecular events behind viral dissemination. We evaluated the contribution of C-type lectin receptors (CLRS) of antigen-presenting cells, widely present in respiratory mucosa and lung tissue. DC-SIGN, L-SIGN, Langerin and MGL bind to diverse glycans of the spike using multiple interaction areas. Using pseudovirus and cells derived from monocytes or T-lymphocytes, we demonstrate that while virus capture by the CLRs examined does not allow direct cell infection, DC/L-SIGN, among these receptors, promote virus transfer to permissive ACE2+ Vero E6 cells. A glycomimetic compound designed against DC-SIGN, enable inhibition of this process. These data have been then confirmed using authentic SARS-CoV-2 virus and human respiratory cell lines. Thus, we described a mechanism potentiating viral spreading of infection.
Assuntos
COVID-19/transmissão , Lectinas Tipo C/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Animais , Antígenos CD/metabolismo , COVID-19/prevenção & controle , Moléculas de Adesão Celular/metabolismo , Linhagem Celular , Chlorocebus aethiops , Humanos , Células Jurkat , Pulmão/metabolismo , Lectinas de Ligação a Manose/metabolismo , Manosídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Mucosa Respiratória/metabolismo , Células VeroRESUMO
We have measured the humoral response to messenger RNA (mRNA) vaccines in COVID-19 naïve and convalescent individuals. Third doses of mRNA COVID-19 vaccines induced a significant increase in potency and breadth of neutralization against SARS-CoV-2 variants of concern (VoC) including Omicron subvariants BA.1, BA.2, and BA.2.12.1, that were cross-neutralized at comparable levels and less for BA.4/5. This booster effect was especially important in naïve individuals that only after the third dose achieved a level that was comparable with that of vaccinated COVID-19 convalescents except for BA.4/5. Avidity of RBD-binding antibodies was also significantly increased in naïve individuals after the third dose, indicating an association between affinity maturation and cross neutralization of VoC. These results suggest that at least three antigenic stimuli by infection or vaccination with ancestral SARS-CoV-2 sequences are required to induce high avidity cross-neutralizing antibodies. Nevertheless, the circulation of new subvariants such as BA.4/5 with partial resistance to neutralization will have to be closely monitored and eventually consider for future vaccine developments.
Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , Vacinas contra COVID-19 , SARS-CoV-2/genética , RNA Mensageiro/genética , Vacinas de mRNA , Anticorpos Neutralizantes , Anticorpos Antivirais , Glicoproteína da Espícula de CoronavírusRESUMO
Currently, the majority of the population has been vaccinated against COVID-19 and/or has experienced SARS-CoV-2 infection either before or after vaccination. The immunological response to repeated episodes of infections is not completely clear. We measured SARS-CoV-2 specific neutralization titers by a pseudovirus assay after BA.1 infection and RBD-specific immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) in a cohort of COVID-19 uninfected and triple vaccinated individuals (breakthrough infection group, BTI) as compared with those previously infected by SARS-CoV-2 (reinfection group, REI) who underwent identical vaccination schedule. SARS-CoV-2 specific neutralizing response after BA.1 infection was significantly higher in the BTI group as compared with the REI. Furthermore, neutralization titers in REI were not significant different from convalescent non reinfected controls. RBD-specific IgG and IgA, but not IgM, were also significantly higher in BTI as compared with REI. Our results show that the first episode of SARS-CoV-2 infection induces a significant increase in neutralizing titers in triple vaccinated individuals and that previous SARS-CoV-2 infection compromise significantly the neutralization response induced by reinfection, even by divergent SARS-CoV-2 variants and at least up to 2 years postinfection, suggesting a fundamental limitation in inducing effective booster through the intranasal route in previously infected individuals.
Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , SARS-CoV-2 , Reinfecção , Imunoglobulina A , Imunoglobulina G , Imunoglobulina M , Vacinação , Anticorpos Neutralizantes , Anticorpos AntiviraisRESUMO
Several anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies (mAbs) have received emergency authorization for coronavirus disease 2019 (COVID-19) treatment. However, most of these mAbs are not active against the highly mutated Omicron SARS-CoV-2 subvariants. We have tested a polyclonal approach of equine anti-SARS-CoV-2 F(ab')2 antibodies that achieved a high level of neutralizing potency against all SARS-CoV-2 variants of concern tested including Omicron BA.1, BA.2, BA.2.12 and BA.4/5. A repertoire of antibodies targeting conserved epitopes in different regions of the spike protein could plausibly account for this remarkable breadth of neutralization. These results warrant the clinical investigation of equine polyclonal F(ab')2 antibodies as a novel therapeutic strategy against COVID-19.
Assuntos
COVID-19 , SARS-CoV-2 , Animais , Cavalos , Humanos , SARS-CoV-2/genética , Anticorpos Monoclonais , Anticorpos Antivirais , Glicoproteína da Espícula de Coronavírus/genética , Anticorpos NeutralizantesRESUMO
We have investigated the evolution of the neutralizing response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants at 8 months after Pfizer-BNT162b2 vaccination in coronavirus disease 2019 (COVID-19)-naive (n = 21) and COVID-19-convalescent (n = 21) individuals. Neutralizing levels declined for all variants (range 2- to 3.7-fold). Eight months after vaccination, a significant proportion (4/21) of naive individuals lacked detectable neutralizing activity against the highly transmissible SARS-CoV-2 delta variant. In the convalescent group, the impressive high initial humoral response resulted in detectable neutralizing antibody levels against all variants throughout this period.
Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Neutralizantes , Anticorpos Antivirais , Vacina BNT162 , COVID-19/prevenção & controle , Humanos , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus , VacinaçãoRESUMO
The synthesis of new biocompatible antiviral materials to fight against the development of multidrug resistance is being widely explored. Due to their unique globular structure and excellent properties, [60]fullerene-based antivirals are very promising bioconjugates. In this work, fullerene derivatives with different topologies and number of glycofullerene units were synthesized by using a SPAAC copper free strategy. This procedure allowed the synthesis of compounds 1-3, containing from 20 to 40 mannose units, in a very efficient manner and in short reaction times under MW irradiation. The glycoderivatives were studied in an infection assay by a pseudotyped viral particle with Ebola virus GP1. The results obtained show that these glycofullerene oligomers are efficient inhibitors of EBOV infection with IC50s in the nanomolar range. In particular, compound 3, with four glycofullerene moieties, presents an outstanding relative inhibitory potency (RIP). We propose that this high RIP value stems from the appropriate topological features that efficiently interact with DC-SIGN.
Assuntos
Ebolavirus , Fulerenos , Doença pelo Vírus Ebola , Antivirais/uso terapêutico , Fulerenos/química , Doença pelo Vírus Ebola/tratamento farmacológico , Humanos , Manose/químicaRESUMO
Crimean-Congo hemorrhagic fever (CCHF) is a widely distributed, viral, tickborne disease. In Europe, cases have been reported only in the southeastern part of the continent. We report two autochthonous cases in Spain. The index patient acquired the disease through a tick bite in the province of Ávila - 300 km away from the province of Cáceres, where viral RNA from ticks was amplified in 2010. The second patient was a nurse who became infected while caring for the index patient. Both were infected with the African 3 lineage of this virus. (Funded by Red de Investigación Cooperativa en Enfermedades Tropicales [RICET] and Efficient Response to Highly Dangerous and Emerging Pathogens at EU [European Union] Level [EMERGE].).
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo/isolamento & purificação , Febre Hemorrágica da Crimeia , Colo/patologia , Busca de Comunicante , Evolução Fatal , Feminino , Vírus da Febre Hemorrágica da Crimeia-Congo/classificação , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Febre Hemorrágica da Crimeia/patologia , Febre Hemorrágica da Crimeia/transmissão , Febre Hemorrágica da Crimeia/virologia , Humanos , Transmissão de Doença Infecciosa do Paciente para o Profissional , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Necrose , Reação em Cadeia da Polimerase , EspanhaRESUMO
After the last epidemic of the Zika virus (ZIKV) in Brazil that peaked in 2016, growing evidence has been demonstrated of the link between this teratogenic flavivirus and microcephaly cases. However, no vaccine or antiviral drug has been approved yet. ZIKV and Dengue viruses (DENV) entry to the host cell takes place through several receptors, including dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), so that the blockade of this receptor through multivalent glycoconjugates supposes a promising biological target to inhibit the infection process. In order to get enhanced multivalency in biocompatible systems, tridecafullerenes appended with up to 360 1,2-mannobiosides have been synthesized using a strain-promoted cycloaddition of azides to alkynes (SPAAC) strategy. These systems have been tested against ZIKV and DENV infection, showing an outstanding activity in the picomolar range.
Assuntos
Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Dengue/tratamento farmacológico , Dissacarídeos/farmacologia , Infecção por Zika virus/tratamento farmacológico , Zika virus/efeitos dos fármacos , Antivirais/síntese química , Antivirais/química , Reação de Cicloadição , Dissacarídeos/química , Fulerenos/química , Estrutura MolecularRESUMO
During 2011-2015, we conducted a Crimean-Congo hemorrhagic fever virus (CCHFV) survey in captured ticks that were feeding mainly on wild and domestic ungulates in Spain, where presence of this virus had been reported previously. We detected CCHFV RNA in Hyalomma lusitanicum and H. marginatum ticks for 3 of the 5 years. The rate of infected ticks was 2.78% (44/1,579), which was similar to those for other countries in Europe with endemic foci for CCHFV (Kosovo, Bulgaria, and Albania). These data confirm the established spread of CCHFV into western Europe. Phylogenetic study of the small RNA segment showed Africa-3 clade as the only genotype identified, although we observed cocirculation of genetic variants during 2011 and 2015. We could not rule out genetic reassortments because of lack of sequence data for the medium and large RNA segments of the virus genome.
Assuntos
Vírus da Febre Hemorrágica da Crimeia-Congo , Febre Hemorrágica da Crimeia/veterinária , Zoonoses/epidemiologia , Zoonoses/virologia , Animais , Vetores Artrópodes/virologia , Genoma Viral , Geografia , Vírus da Febre Hemorrágica da Crimeia-Congo/classificação , Vírus da Febre Hemorrágica da Crimeia-Congo/genética , Vírus da Febre Hemorrágica da Crimeia-Congo/isolamento & purificação , Humanos , Filogenia , Vigilância em Saúde Pública , Espanha/epidemiologia , Carrapatos/virologiaRESUMO
Background: In Ebola virus (EBOV) infection, the specific neutralizing activity of convalescent plasma against other members of the Ebolavirus genus has not been extensively analyzed. Methods: We measured the neutralizing activity in plasma from 3 survivors of the recent outbreak due to the Makona variant of EBOV and tested its neutralizing potency against other variants of EBOV (ie, Mayinga and Kikwit) and against Sudan virus (SUDV), Bundibugyo virus (BDBV), and Reston virus (RESTV), using a glycoprotein (GP)-pseudotyped lentiviral system both with full-length GP and in vitro-cleaved GP (GPCL). Results: Convalescent plasma specimens from survivors of EBOV infection showed low neutralizing activity against full-length GPs of SUDV, BDBV, RESTV, and EBOV variants Mayinga and Kikwit. However, broad and potent neutralizing activity was observed against the GPCL forms of SUDV, BDBV, and RESTV. Discussion: Removal of the mucin-like domain and glycan cap from the GP of members of the Ebolavirus genus presumably exposes conserved epitopes in or in the vicinity of the receptor binding site and internal fusion loop that are readily amenable to neutralization. These types of broad neutralizing antibodies could be induced by using immunogens mimicking GPCL.
Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Ebolavirus/imunologia , Doença pelo Vírus Ebola/imunologia , Adulto , Feminino , Glicoproteínas/imunologia , Humanos , Imunoglobulina G/sangue , Pessoa de Meia-IdadeRESUMO
SWCNTs, MWCNTs, and SWCNHs have been employed as virus-mimicking nanocarbon platforms for the multivalent presentation of carbohydrates in an artificial Ebola virus infection model assay. These carbon nanoforms have been chemically modified by the covalent attachment of glycodendrons and glycofullerenes using the CuAAC "click chemistry" approach. This modification dramatically increases the water solubility of these structurally different nanocarbons. Their efficiency in blocking DC-SIGN-mediated viral infection by an artificial Ebola virus has been tested in a cellular experimental assay, finding that glycoconjugates based on MWCNTs functionalized with glycofullerenes are potent inhibitors of viral infection.
Assuntos
Antivirais/uso terapêutico , Carbono/química , Glicoconjugados/química , Glicoconjugados/uso terapêutico , Doença pelo Vírus Ebola/tratamento farmacológico , Nanoestruturas/química , Química Click , Microscopia Eletrônica de Transmissão , Análise Espectral RamanRESUMO
Since the first documented autochthonous transmission of chikungunya virus in the Caribbean island of Saint Martin in 2013, the infection has been reported within the Caribbean region as well as North, Central and South America. The risk of autochthonous transmission of chikungunya virus becoming established in Spain may be elevated due to the large numbers of travellers returning to Spain from countries affected by the 2013 epidemic in the Caribbean and South America, as well as the existence of the Aedes albopictus vector in certain parts of Spain. We retrospectively analysed the laboratory diagnostic database of the National Centre for Microbiology, Institute of Health Carlos III (CNM-ISCIII) from 2008 to 2014. During the study period, 264 confirmed cases, of 1,371 suspected cases, were diagnosed at the CNM-ISCIII. In 2014 alone, there were 234 confirmed cases. The highest number of confirmed cases were reported from the Dominican Republic (n = 136), Venezuela (n = 30) and Haiti (n = 11). Six cases were viraemic in areas of Spain where the vector is present. This report highlights the need for integrated active case and vector surveillance in Spain and other parts of Europe where chikungunya virus may be introduced by returning travellers.
Assuntos
Febre de Chikungunya/diagnóstico , Vírus Chikungunya/isolamento & purificação , Febre/etiologia , Viagem , Aedes/virologia , Animais , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/virologia , Vírus Chikungunya/genética , Surtos de Doenças , República Dominicana , Feminino , Haiti , Humanos , Insetos Vetores/virologia , Masculino , RNA Viral , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Vigilância de Evento Sentinela , Espanha/epidemiologia , VenezuelaRESUMO
The presentation of short viral peptide antigens by human leukocyte antigen (HLA) class I molecules on cell surfaces is a key step in the activation of cytotoxic T lymphocytes, which mediate the killing of pathogen-infected cells or initiate autoimmune tissue damage. HLA-B27 is a well known class I molecule that is used to study both facets of the cellular immune response. Using mass spectrometry analysis of complex HLA-bound peptide pools isolated from large amounts of HLA-B*2705(+) cells, we identified 200 naturally processed HLA-B*2705 ligands. Our analyses revealed that a change in the position (P) 2 anchor motif was detected in the 3% of HLA-B*2705 ligands identified. B*2705 class I molecules were able to bind these six GlnP2 peptides, which showed significant homology to pathogenic bacterial sequences, with a broad range of affinities. One of these ligands was able to bind with distinct conformations to HLA-B27 subtypes differentially associated with ankylosing spondylitis. These conformational differences could be sufficient to initiate autoimmune damage in patients with ankylosing spondylitis-associated subtypes. Therefore, these kinds of peptides (short, with GlnP2, and similar low affinity to all HLA-B27 subtypes tested but with unlike conformations in differentially ankylosing spondylitis-associated subtypes) must not be excluded from future researches involving potential arthritogenic peptides.
Assuntos
Antígeno HLA-B27/imunologia , Peptídeos/imunologia , Espondiloartropatias/imunologia , Motivos de Aminoácidos , Linhagem Celular , Antígeno HLA-B27/genética , Antígeno HLA-B27/metabolismo , Humanos , Peptídeos/genética , Peptídeos/metabolismo , Ligação Proteica/genética , Ligação Proteica/imunologia , Espondiloartropatias/genética , Espondiloartropatias/metabolismo , Espondiloartropatias/patologiaRESUMO
The transporter associated with antigen processing (TAP) enables the flow of viral peptides generated in the cytosol by the proteasome and other proteases to the endoplasmic reticulum, where they complex with nascent human leukocyte antigen (HLA) class I. Later, these peptide-HLA class I complexes can be recognized by CD8(+) lymphocytes. Cancerous cells and infected cells in which TAP is blocked, as well as individuals with unusable TAP complexes, are able to present peptides on HLA class I by generating them through TAP-independent processing pathways. Here, we identify a physiologically processed HLA-E ligand derived from the D8L protein in TAP-deficient vaccinia virus-infected cells. This natural high affinity HLA-E class I ligand uses alternative interactions to the anchor motifs previously described to be presented on nonclassical HLA class I molecules. This octameric peptide was also presented on HLA-Cw1 with similar binding affinity on both classical and nonclassical class I molecules. In addition, this viral peptide inhibits HLA-E-mediated cytolysis by natural killer cells. Comparison between the amino acid sequences of the presenting HLA-E and HLA-Cw1 alleles revealed a shared structural motif in both HLA class molecules, which could be related to their observed similar cross-reactivity affinities. This motif consists of several residues located on the floor of the peptide-binding site. These data expand the role of HLA-E as an antigen-presenting molecule.
Assuntos
Transportadores de Cassetes de Ligação de ATP/imunologia , Apresentação de Antígeno , Antígenos Virais/imunologia , Linfócitos T CD8-Positivos/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Proteínas de Membrana/imunologia , Vaccinia virus/imunologia , Vacínia/imunologia , Proteínas Estruturais Virais/imunologia , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Motivos de Aminoácidos , Antígenos Virais/genética , Antígenos Virais/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular , Antígenos HLA-C/genética , Antígenos HLA-C/imunologia , Antígenos HLA-C/metabolismo , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Peptídeos/genética , Peptídeos/imunologia , Peptídeos/metabolismo , Vacínia/genética , Vacínia/metabolismo , Vaccinia virus/genética , Vaccinia virus/metabolismo , Proteínas Estruturais Virais/genética , Proteínas Estruturais Virais/metabolismo , Antígenos HLA-ERESUMO
The transporter associated with antigen processing (TAP) delivers the viral proteolytic products generated by the proteasome in the cytosol to the endoplasmic reticulum lumen that are subsequently recognized by cytotoxic T lymphocytes (CTLs). However, several viral epitopes have been identified in TAP-deficient models. Using mass spectrometry to analyze complex human leukocyte antigen (HLA)-bound peptide pools isolated from large numbers of TAP-deficient vaccinia virus-infected cells, we identified 11 ligands naturally presented by four different HLA-A, HLA-B, and HLA-C class I molecules. Two of these ligands were presented by two different HLA class I alleles, and, as a result, 13 different HLA-peptide complexes were formed simultaneously in the same vaccinia virus-infected cells. In addition to the high-affinity ligands, one low-affinity peptide restricted by each of the HLA-A, HLA-B, and HLA-C class I molecules was identified. Both high- and low-affinity ligands generated long-term memory CTL responses to vaccinia virus in an HLA-A2-transgenic mouse model. The processing and presentation of two vaccinia virus-encoded HLA-A2-restricted antigens took place via proteasomal and nonproteasomal pathways, which were blocked in infected cells with chemical inhibitors specific for different subsets of metalloproteinases. These data have implications for the study of the effectiveness of early empirical vaccination with cowpox virus against smallpox disease.
Assuntos
Transportadores de Cassetes de Ligação de ATP/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Vaccinia virus/imunologia , Vacínia/imunologia , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Apresentação de Antígeno , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/virologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Linhagem Celular , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Ligantes , Camundongos , Camundongos Knockout , Vacínia/genética , Vacínia/virologia , Vaccinia virus/genéticaRESUMO
DC-SIGN is a C-type lectin expressed in myeloid cells such as immature dendritic cells and macrophages. Through glycan recognition in viral envelope glycoproteins, DC-SIGN has been shown to act as a receptor for a number of viral agents such as HIV, Ebola virus, SARS-CoV, and SARS-CoV-2. Using a system of Vesicular Stomatitis Virus pseudotyped with MERS-CoV spike protein, here, we show that DC-SIGN is partially responsible for MERS-CoV infection of dendritic cells and that DC-SIGN efficiently mediates trans-infection of MERS-CoV from dendritic cells to susceptible cells, indicating a potential role of DC-SIGN in MERS-CoV dissemination and pathogenesis.
Assuntos
Coronavírus da Síndrome Respiratória do Oriente Médio , Coronavírus da Síndrome Respiratória do Oriente Médio/metabolismo , Receptores de Superfície Celular/metabolismo , Moléculas de Adesão Celular/metabolismo , Lectinas Tipo C/metabolismo , Células Dendríticas/metabolismoRESUMO
Toll-like receptor 7 (TLR7) is an endosomal pathogen-associated molecular pattern (PAMP) receptor that senses single-stranded RNA (ssRNA) and whose engagement results in the production of type I IFN and pro-inflammatory cytokines upon viral exposure. Recent genetic studies have established that a dysfunctional TLR7-initiated signaling is directly linked to the development of inflammatory responses. We present evidence that TLR7 is preferentially expressed by monocyte-derived macrophages generated in the presence of M-CSF (M-MØ). We now show that TLR7 activation in M-MØ triggers a weak MAPK, NFκB, and STAT1 activation and results in low production of type I IFN. Of note, TLR7 engagement reprograms MAFB+ M-MØ towards a pro-inflammatory transcriptional profile characterized by the expression of neutrophil-attracting chemokines (CXCL1-3, CXCL5, CXCL8), whose expression is dependent on the transcription factors MAFB and AhR. Moreover, TLR7-activated M-MØ display enhanced pro-inflammatory responses and a stronger production of neutrophil-attracting chemokines upon secondary stimulation. As aberrant TLR7 signaling and enhanced pulmonary neutrophil/lymphocyte ratio associate with impaired resolution of virus-induced inflammatory responses, these results suggest that targeting macrophage TLR7 might be a therapeutic strategy for viral infections where monocyte-derived macrophages exhibit a pathogenic role.
Assuntos
Monócitos , Receptor 7 Toll-Like , Humanos , Receptor 7 Toll-Like/metabolismo , Monócitos/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Infiltração de Neutrófilos , Citocinas/metabolismo , Macrófagos/metabolismo , Quimiocinas/metabolismoRESUMO
Monocyte-derived macrophages, the major source of pathogenic macrophages in COVID-19, are oppositely instructed by macrophage CSF (M-CSF) or granulocyte macrophage CSF (GM-CSF), which promote the generation of antiinflammatory/immunosuppressive MAFB+ (M-MØ) or proinflammatory macrophages (GM-MØ), respectively. The transcriptional profile of prevailing macrophage subsets in severe COVID-19 led us to hypothesize that MAFB shapes the transcriptome of pulmonary macrophages driving severe COVID-19 pathogenesis. We have now assessed the role of MAFB in the response of monocyte-derived macrophages to SARS-CoV-2 through genetic and pharmacological approaches, and we demonstrate that MAFB regulated the expression of the genes that define pulmonary pathogenic macrophages in severe COVID-19. Indeed, SARS-CoV-2 potentiated the expression of MAFB and MAFB-regulated genes in M-MØ and GM-MØ, where MAFB upregulated the expression of profibrotic and neutrophil-attracting factors. Thus, MAFB determines the transcriptome and functions of the monocyte-derived macrophage subsets that underlie pulmonary pathogenesis in severe COVID-19 and controls the expression of potentially useful biomarkers for COVID-19 severity.