Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 113
Filtrar
1.
Recurso na Internet em Português | LIS - Localizador de Informação em Saúde | ID: lis-LISBR1.1-46945

RESUMO

Site do Ministério da Saúde. (Brasil). Tirando dúvidas sobre o corona Virús. O que é o Virús, suas causas, sintomas, tratamento, diagnostico é prevenção Saiba mais sobre o Coronavirus...


Assuntos
Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Coronavirus Humano 229E/patogenicidade , Infecções por Coronavirus/prevenção & controle
2.
ACS Appl Mater Interfaces ; 11(22): 19799-19807, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31099550

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) causes a severe acute respiratory syndrome-like illness with high pathogenicity and mortality due to the lack of effective therapeutics. Currently, only few antiviral agents are available for the treatment of MERS, but their effects have been greatly impaired by low antiviral activity, poor metabolic stability, and serious adverse effects. Therefore, the development of effective treatment for MERS is urgently needed. In this study, a series of heptad repeat 1 (HR1) peptide inhibitors have been developed to inhibit HR1/HR2-mediated membrane fusion between MERS-CoV and host cells, which is the major pathway of MERS-CoV-induced host infections. Particularly, peptide pregnancy-induced hypertension (PIH) exhibits potent inhibitory activity with IC50 of 1.171 µM, and its inhibitory effects can be further increased to 10-fold by forming a gold nanorod complex (PIH-AuNRs). In addition, PIH-AuNRs display enhanced metabolic stability and biocompatibility in vitro and in vivo and, therefore, effectively prevent MERS-CoV-associated membrane fusion. In summary, PIH-AuNRs represent a novel class of antiviral agents and have a great potential in treating MERS in the clinic.


Assuntos
Antivirais/química , Antivirais/farmacologia , Ouro/química , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Nanotubos/química , Peptídeos/química , Peptídeos/farmacologia , Animais , Linhagem Celular , Dicroísmo Circular , Feminino , Humanos , Camundongos , Coronavírus da Síndrome Respiratória do Oriente Médio/efeitos dos fármacos , Estrutura Secundária de Proteína
3.
J Microbiol Biotechnol ; 29(5): 813-819, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-30982320

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) induces severe respiratory impairment with a reported mortality rate of ~36% in humans. The absence of clinically available MERS-CoV vaccines and treatments to date has resulted in uncontrolled incidence and propagation of the virus. In vaccine design, fusion with the IgG Fc domain is reported to increase the immunogenicity of various vaccine antigens. However, limited reports have documented the potential negative effects of Fc fusion on vaccine antigens. To determine whether Fc fusion affects the immunogenicity of MERS-CoV antigen, we constructed a Fcassociated MERS-CoV spike protein (eS770-Fc, 110 kDa), whereby human IgG4 Fc domain was fused to MERS-CoV spike protein (eS770) via a Gly/Pro linker using baculovirus as the expression system. For comparative analyses, two eS770 proteins lacking the IgG4 Fc domain were generated using the IdeS protease (eS770-ΔFc) or His tag attachment (eS770-His) and the immunogenicity of the above constructs were examined following intramuscular immunization in mice. Contrary to expectations, non-Fc spike proteins (eS770-ΔFc, eS770-His; 90 kDa) showed higher immunogenicity than the Fc fusion protein (eS770-Fc). Moreover, unlike non- Fc spike proteins, eS770-Fc immunization did not elicit neutralizing antibodies against MERSCoV. The lower immunogenicity of Fc-fused eS770 was related to alterations in the structural conformation of the spike protein. Taken together, our results indicate that IgG Fc fusion reduces the immunogenicity of eS770 by interfering with the proper folding structure.


Assuntos
Infecções por Coronavirus/prevenção & controle , Imunogenicidade da Vacina , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Dobramento de Proteína , Proteínas Recombinantes de Fusão/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais , Antígenos Virais/genética , Feminino , Imunização , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G , Camundongos , Camundongos Endogâmicos BALB C , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Testes de Neutralização , Células Sf9 , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Vacinação , Vacinas de Subunidades/imunologia , Vacinas Virais/genética
4.
Viruses ; 11(3)2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30893947

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic pathogen that causes respiratory infection in humans, ranging from asymptomatic to severe pneumonia. In dromedary camels, the virus only causes a mild infection but it spreads efficiently between animals. Differences in the behavior of the virus observed between individuals, as well as between humans and dromedary camels, highlight the role of host factors in MERS-CoV pathogenesis and transmission. One of these host factors, the MERS-CoV receptor dipeptidyl peptidase-4 (DPP4), may be a critical determinant because it is variably expressed in MERS-CoV-susceptible species as well as in humans. This could partially explain inter- and intraspecies differences in the tropism, pathogenesis, and transmissibility of MERS-CoV. In this review, we explore the role of DPP4 and other host factors in MERS-CoV transmission and pathogenesis-such as sialic acids, host proteases, and interferons. Further characterization of these host determinants may potentially offer novel insights to develop intervention strategies to tackle ongoing outbreaks.


Assuntos
Infecções por Coronavirus/transmissão , Interações Hospedeiro-Patógeno , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Infecções Respiratórias/transmissão , Tropismo Viral , Animais , Camelus/virologia , Quirópteros/virologia , Dipeptidil Peptidase 4/metabolismo , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/fisiologia , Infecções Respiratórias/virologia , Replicação Viral
5.
mBio ; 10(2)2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30914508

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) was first identified in 2012 as a novel etiological agent of severe respiratory disease in humans. As during infection by other viruses, host sensing of viral double-stranded RNA (dsRNA) induces several antiviral pathways. These include interferon (IFN), oligoadenylate synthetase (OAS)-RNase L, and protein kinase R (PKR). Coronaviruses, including MERS-CoV, potently suppress the activation of these pathways, inducing only modest host responses. Our study describes the functions of two accessory proteins unique to MERS-CoV and related viruses, NS4a and NS4b, during infection in human airway epithelium-derived A549 cells. NS4a has been previously characterized as a dsRNA binding protein, while NS4b is a 2',5'-phosphodiesterase with structural and enzymatic similarity to NS2 encoded by mouse hepatitis virus (MHV). We found that deletion of NS4a results in increased interferon lambda (IFNL1) expression, as does mutation of either the catalytic site or nuclear localization sequence of NS4b. All of the mutant viruses we tested exhibited slight decreases in replication. We previously reported that, like MHV NS2, NS4b antagonizes OAS-RNase L, but suppression of IFN is a previously unidentified function for viral phosphodiesterases. Unexpectedly, deletion of NS4a does not result in robust activation of the PKR or OAS-RNase L pathways. Therefore, MERS-CoV likely encodes other proteins that contribute to suppression or evasion of these antiviral innate immune pathways that should be an important focus of future work. This study provides additional insight into the complex interactions between MERS-CoV and the host immune response.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) is the second novel zoonotic coronavirus to emerge in the 21st century and cause outbreaks of severe respiratory disease. More than 2,200 cases and 800 deaths have been reported to date, yet there are no licensed vaccines or treatments. Coronaviruses encode unique accessory proteins that are not required for replication but most likely play roles in immune antagonism and/or pathogenesis. Our study describes the functions of MERS-CoV accessory proteins NS4a and NS4b during infection of a human airway-derived cell line. Loss of these accessory proteins during MERS-CoV infection leads to host antiviral activation and modestly attenuates replication. In the case of both NS4a and NS4b, we have identified roles during infection not previously described, yet the lack of robust activation suggests much remains to be learned about the interactions between MERS-CoV and the infected host.


Assuntos
Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , RNA de Cadeia Dupla/imunologia , RNA Viral/imunologia , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais Reguladoras e Acessórias/metabolismo , Células A549 , Células Epiteliais/virologia , Deleção de Genes , Humanos , Imunidade Inata , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Mutação , Proteínas não Estruturais Virais/genética , Proteínas Virais Reguladoras e Acessórias/genética , Replicação Viral
6.
J Vis Exp ; (145)2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30882796

RESUMO

The protocol aims to generate coronavirus (CoV) spike (S) fusion protein pseudotyped particles with a murine leukemia virus (MLV) core and luciferase reporter, using a simple transfection procedure of the widely available HEK-293T cell line. Once formed and released from producer cells, these pseudovirions incorporate a luciferase reporter gene. Since they only contain the heterologous coronavirus spike protein on their surface, the particles behave like their native coronavirus counterparts for entry steps. As such, they are the excellent surrogates of native virions for studying viral entry into host cells. Upon successful entry and infection into target cells, the luciferase reporter gets integrated into the host cell genome and is expressed. Using a simple luciferase assay, transduced cells can be easily quantified. An important advantage of the procedure is that it can be performed in biosafety level 2 (BSL-2) facilities instead of BSL-3 facilities required for work with highly pathogenic coronaviruses such as Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV). Another benefit comes from its versatility as it can be applied to envelope proteins belonging to all three classes of viral fusion proteins, such as the class I influenza hemagglutinin (HA) and Ebola virus glycoprotein (GP), the class II Semliki forest virus E1 protein, or the class III vesicular stomatitis virus G glycoprotein. A limitation of the methodology is that it can only recapitulate virus entry steps mediated by the envelope protein being investigated. For studying other viral life cycle steps, other methods are required. Examples of the many applications these pseudotype particles can be used in include investigation of host cell susceptibility and tropism and testing the effects of virus entry inhibitors to dissect viral entry pathways used.


Assuntos
Contenção de Riscos Biológicos , Coronavirus/patogenicidade , Animais , Células HEK293 , Humanos , Camundongos , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Vírus da SARS/patogenicidade , Glicoproteína da Espícula de Coronavírus/metabolismo , Vírion/patogenicidade , Internalização do Vírus/efeitos dos fármacos
7.
Viruses ; 11(2)2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30781790

RESUMO

Insectivorous bats are speculated to be ancestral hosts of Middle-East respiratory syndrome (MERS) coronavirus (CoV). MERS-CoV causes disease in humans with thirty-five percent fatality, and has evolved proteins that counteract human antiviral responses. Since bats experimentally infected with MERS-CoV do not develop signs of disease, we tested the hypothesis that MERS-CoV would replicate less efficiently in bat cells than in human cells because of its inability to subvert antiviral responses in bat cells. We infected human and bat (Eptesicus fuscus) cells with MERS-CoV and observed that the virus grew to higher titers in human cells. MERS-CoV also effectively suppressed the antiviral interferon beta (IFNß) response in human cells, unlike in bat cells. To determine if IRF3, a critical mediator of the interferon response, also regulated the response in bats, we examined the response of IRF3 to poly(I:C), a synthetic analogue of viral double-stranded RNA. We observed that bat IRF3 responded to poly(I:C) by nuclear translocation and post-translational modifications, hallmarks of IRF3 activation. Suppression of IRF3 by small-interfering RNA (siRNA) demonstrated that IRF3 was critical for poly(I:C) and MERS-CoV induced induction of IFNß in bat cells. Our study demonstrates that innate antiviral signaling in E. fuscus bat cells is resistant to MERS-CoV-mediated subversion.


Assuntos
Quirópteros/virologia , Imunidade Inata , Fator Regulador 3 de Interferon/imunologia , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Animais , Linhagem Celular , Técnicas de Silenciamento de Genes , Técnicas de Inativação de Genes , Humanos , Evasão da Resposta Imune , Fator Regulador 3 de Interferon/genética , Interferon beta/imunologia , Rim/citologia , Rim/virologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Filogenia , Transdução de Sinais
8.
Viruses ; 11(1)2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30646565

RESUMO

Coronaviruses (CoVs) have formerly been regarded as relatively harmless respiratory pathogens to humans. However, two outbreaks of severe respiratory tract infection, caused by the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), as a result of zoonotic CoVs crossing the species barrier, caused high pathogenicity and mortality rates in human populations. This brought CoVs global attention and highlighted the importance of controlling infectious pathogens at international borders. In this review, we focus on our current understanding of the epidemiology, pathogenesis, prevention, and treatment of SARS-CoV and MERS-CoV, as well as provides details on the pivotal structure and function of the spike proteins (S proteins) on the surface of each of these viruses. For building up more suitable animal models, we compare the current animal models recapitulating pathogenesis and summarize the potential role of host receptors contributing to diverse host affinity in various species. We outline the research still needed to fully elucidate the pathogenic mechanism of these viruses, to construct reproducible animal models, and ultimately develop countermeasures to conquer not only SARS-CoV and MERS-CoV, but also these emerging coronaviral diseases.


Assuntos
Infecções por Coronavirus/prevenção & controle , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Vírus da SARS/patogenicidade , Síndrome Respiratória Aguda Grave/prevenção & controle , Animais , China/epidemiologia , Quirópteros/virologia , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/epidemiologia , Modelos Animais de Doenças , Genoma Viral , Humanos , Camundongos , Oriente Médio/epidemiologia , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Vírus da SARS/genética , Síndrome Respiratória Aguda Grave/tratamento farmacológico , Síndrome Respiratória Aguda Grave/epidemiologia , Glicoproteína da Espícula de Coronavírus , Vacinas Virais/imunologia , Zoonoses/transmissão , Zoonoses/virologia
9.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30626685

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) infection can manifest as a mild illness, acute respiratory distress, organ failure, or death. Several animal models have been established to study disease pathogenesis and to develop vaccines and therapeutic agents. Here, we developed transgenic (Tg) mice on a C57BL/6 background; these mice expressed human CD26/dipeptidyl peptidase 4 (hDPP4), a functional receptor for MERS-CoV, under the control of an endogenous hDPP4 promoter. We then characterized this mouse model of MERS-CoV. The expression profile of hDPP4 in these mice was almost equivalent to that in human tissues, including kidney and lung; however, hDPP4 was overexpressed in murine CD3-positive cells within peripheral blood and lymphoid tissues. Intranasal inoculation of young and adult Tg mice with MERS-CoV led to infection of the lower respiratory tract and pathological evidence of acute multifocal interstitial pneumonia within 7 days, with only transient loss of body weight. However, the immunopathology in young and adult Tg mice was different. On day 5 or 7 postinoculation, lungs of adult Tg mice contained higher levels of proinflammatory cytokines and chemokines associated with migration of macrophages. These results suggest that the immunopathology of MERS-CoV infection in the Tg mouse is age dependent. The mouse model described here will increase our understanding of disease pathogenesis and host mediators that protect against MERS-CoV infection.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) infections are endemic in the Middle East and a threat to public health worldwide. Rodents are not susceptible to the virus because they do not express functional receptors; therefore, we generated a new animal model of MERS-CoV infection based on transgenic mice expressing human DPP4 (hDPP4). The pattern of hDPP4 expression in this model was similar to that in human tissues (except lymphoid tissue). In addition, MERS-CoV was limited to the respiratory tract. Here, we focused on host factors involved in immunopathology in MERS-CoV infection and clarified differences in antiviral immune responses between young and adult transgenic mice. This new small-animal model could contribute to more in-depth study of the pathology of MERS-CoV infection and aid development of suitable treatments.


Assuntos
Infecções por Coronavirus/metabolismo , Dipeptidil Peptidase 4/metabolismo , Pulmão/virologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Animais , Linhagem Celular , Infecções por Coronavirus/virologia , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Macrófagos/metabolismo , Macrófagos/virologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Infecções Respiratórias/metabolismo , Infecções Respiratórias/virologia , Células Vero
10.
Nat Rev Microbiol ; 17(3): 181-192, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30531947

RESUMO

Severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) are two highly transmissible and pathogenic viruses that emerged in humans at the beginning of the 21st century. Both viruses likely originated in bats, and genetically diverse coronaviruses that are related to SARS-CoV and MERS-CoV were discovered in bats worldwide. In this Review, we summarize the current knowledge on the origin and evolution of these two pathogenic coronaviruses and discuss their receptor usage; we also highlight the diversity and potential of spillover of bat-borne coronaviruses, as evidenced by the recent spillover of swine acute diarrhoea syndrome coronavirus (SADS-CoV) to pigs.


Assuntos
Coronavirus/genética , Coronavirus/patogenicidade , Variação Genética , Genoma Viral , Alphacoronavirus/genética , Alphacoronavirus/patogenicidade , Animais , Quirópteros/virologia , Infecções por Coronavirus , Evolução Molecular , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Filogenia , Vírus da SARS/genética , Vírus da SARS/patogenicidade , Síndrome Respiratória Aguda Grave , Suínos/virologia
11.
J Virol ; 93(2)2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30404801

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) poses a threat to public health. The virus is endemic in the Middle East but can be transmitted to other countries by travel activity. The introduction of MERS-CoV into the Republic of Korea by an infected traveler resulted in a hospital outbreak of MERS that entailed 186 cases and 38 deaths. The MERS-CoV spike (S) protein binds to the cellular protein DPP4 via its receptor binding domain (RBD) and mediates viral entry into target cells. During the MERS outbreak in Korea, emergence and spread of viral variants that harbored mutations in the RBD, D510G and I529T, was observed. Counterintuitively, these mutations were found to reduce DPP4 binding and viral entry into target cells. In this study, we investigated whether they also exerted proviral effects. We confirm that changes D510G and I529T reduce S protein binding to DPP4 but show that this reduction only translates into diminished viral entry when expression of DPP4 on target cells is low. Neither mutation modulated S protein binding to sialic acids, S protein activation by host cell proteases, or inhibition of S protein-driven entry by interferon-induced transmembrane proteins. In contrast, changes D510G and I529T increased resistance of S protein-driven entry to neutralization by monoclonal antibodies and sera from MERS patients. These findings indicate that MERS-CoV variants with reduced neutralization sensitivity were transmitted during the Korean outbreak and that the responsible mutations were compatible with robust infection of cells expressing high levels of DPP4.IMPORTANCE MERS-CoV has pandemic potential, and it is important to identify mutations in viral proteins that might augment viral spread. In the course of a large hospital outbreak of MERS in the Republic of Korea in 2015, the spread of a viral variant that contained mutations in the viral spike protein was observed. These mutations were found to reduce receptor binding and viral infectivity. However, it remained unclear whether they also exerted proviral effects. We demonstrate that these mutations reduce sensitivity to antibody-mediated neutralization and are compatible with robust infection of target cells expressing large amounts of the viral receptor DPP4.


Assuntos
Infecções por Coronavirus/transmissão , Dipeptidil Peptidase 4/metabolismo , Farmacorresistência Viral , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Mutação , Glicoproteína da Espícula de Coronavírus/genética , Idoso , Anticorpos Monoclonais/farmacologia , Anticorpos Neutralizantes/farmacologia , Sítios de Ligação , Infecções por Coronavirus/metabolismo , Regulação para Baixo , Humanos , Masculino , Pessoa de Meia-Idade , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Ligação Proteica , República da Coreia , Ácidos Siálicos/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do Vírus
12.
BMB Rep ; 52(6): 397-402, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30355437

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) uses the spike (S) glycoprotein to recognize and enter target cells. In this study, we selected two epitope peptide sequences within the receptor binding domain (RBD) of the MERS-CoV S protein. We used a complex consisting of the epitope peptide of the MERS-CoV S protein and CpG-DNA encapsulated in liposome complex to immunize mice, and produced the monoclonal antibodies 506-2G10G5 and 492-1G10E4E2. The western blotting data showed that both monoclonal antibodies detected the S protein and immunoprecipitated the native form of the S protein. Indirect immunofluorescence and confocal analysis suggested strong reactivity of the antibodies towards the S protein of MERS-CoV virus infected Vero cells. Furthermore, the 506-2G10G5 monoclonal antibody significantly reduced plaque formation in MERS-CoV infected Vero cells compared to normal mouse IgG and 492-1G10E4E2. Thus, we successfully produced a monoclonal antibody directed against the RBD domain of the S protein which could be used in the development of diagnostics and therapeutic applications in the future. [BMB Reports 2019; 52(6): 397-402].


Assuntos
Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Animais , Anticorpos Monoclonais/isolamento & purificação , Ilhas de CpG/imunologia , DNA , Epitopos/imunologia , Humanos , Lipossomos , Camundongos , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Peptídeos/imunologia , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/metabolismo , Células Vero
13.
J Cell Physiol ; 234(3): 2143-2151, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30146782

RESUMO

Coronavirus (CoV) infections are commonly associated with respiratory and enteric disease in humans and animals. In 2012, a new human disease called Middle East respiratory syndrome (MERS) emerged in the Middle East. MERS was caused by a virus that was originally called human coronavirus-Erasmus Medical Center/2012 but was later renamed as Middle East respiratory syndrome coronavirus (MERS-CoV). MERS-CoV causes high fever, cough, acute respiratory tract infection, and multiorgan dysfunction that may eventually lead to the death of the infected individuals. The exact origin of MERS-CoV remains unknown, but the transmission pattern and evidence from virological studies suggest that dromedary camels are the major reservoir host, from which human infections may sporadically occur through the zoonotic transmission. Human to human transmission also occurs in healthcare facilities and communities. Recent studies on Middle Eastern respiratory continue to highlight the need for further understanding the virus-host interactions that govern disease severity and infection outcome. In this review, we have highlighted the major mechanisms of immune evasion strategies of MERS-CoV. We have demonstrated that M, 4a, 4b proteins and Plppro of MERS-CoV inhibit the type I interferon (IFN) and nuclear factor-κB signaling pathways and therefore facilitate innate immune evasion. In addition, nonstructural protein 4a (NSP4a), NSP4b, and NSP15 inhibit double-stranded RNA sensors. Therefore, the mentioned proteins limit early induction of IFN and cause rapid apoptosis of macrophages. MERS-CoV strongly inhibits the activation of T cells with downregulation of antigen presentation. In addition, uncontrolled secretion of interferon É£-induced protein 10 and monocyte chemoattractant protein-1 can suppress proliferation of human myeloid progenitor cells.


Assuntos
Infecções por Coronavirus/imunologia , Imunidade Inata/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Evasão da Resposta Imune/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade
14.
Transbound Emerg Dis ; 66(2): 831-841, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30520548

RESUMO

This study investigated the co-localization of the Middle East respiratory syndrome coronavirus (MERS-CoV) and its receptor dipeptidyl peptidase-4 (DPP4) by immunohistochemistry (IHC) across respiratory and lymphoid organs of experimentally MERS-CoV infected pigs and llamas. Also, scanning electron microscopy was performed to assess the ciliary integrity of respiratory epithelial cells in both species. In pigs, on day 2 post-inoculation (p.i.), DPP4-MERS-CoV co-localization was detected in medial turbinate epithelium. On day 4 p.i., the virus/receptor co-localized in frontal and medial turbinate epithelial cells in pigs, and epithelial cells distributed unevenly through the whole nasal cavity and in the cervical lymph node in llamas. MERS-CoV viral nucleocapsid was mainly detected in upper respiratory tract sites on days 2 and 4 p.i. in pigs and day 4 p.i. in llamas. No MERS-CoV was detected on day 24 p.i. in any tissue by IHC. While pigs showed severe ciliary loss in the nasal mucosa both on days 2 and 4 p.i. and moderate loss in the trachea on days 4 and 24 p.i., ciliation of respiratory organs in llamas was not significantly affected. Obtained data confirm the role of DPP4 for MERS-CoV entry in respiratory epithelial cells of llamas. Notably, several nasal epithelial cells in pigs were found to express viral antigen but not DPP4, suggesting the possible existence of other molecule/s facilitating virus entry or down regulation of DPP4 upon infection.


Assuntos
Camelídeos Americanos/virologia , Infecções por Coronavirus/veterinária , Dipeptidil Peptidase 4/metabolismo , Tecido Linfoide/enzimologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Sistema Respiratório/enzimologia , Doenças dos Suínos/virologia , Animais , Infecções por Coronavirus/virologia , Imuno-Histoquímica/veterinária , Microscopia Eletrônica de Varredura/veterinária , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Receptores Virais/metabolismo , Suínos
15.
Biosci Rep ; 38(5)2018 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-30242057

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) causes respiratory diseases in humans and has a high mortality rate. During infection, MERS-CoV regulates several host cellular processes including antiviral response genes. In order to determine if the nucleocapsid protein of MERS-CoV (MERS-N) plays a role in viral-host interactions, a murine monoclonal antibody was generated so as to allow detection of the protein in infected cells as well as in overexpression system. Then, MERS-N was stably overexpressed in A549 cells, and a PCR array containing 84 genes was used to screen for genes transcriptionally regulated by it. Several up-regulated antiviral genes, namely TNF, IL6, IL8, and CXCL10, were selected for independent validation in transiently transfected 293FT cells. Out of these, the overexpression of MERS-N was found to up-regulate CXCL10 at both transcriptional and translational levels. Interestingly, CXCL10 has been reported to be up-regulated in MERS-CoV infected airway epithelial cells and lung fibroblast cells, as well as monocyte-derived macrophages and dendritic cells. High secretions and persistent increase of CXCL10 in MERS-CoV patients have been also associated with severity of disease. To our knowledge, this is the first report showing that the MERS-N protein is one of the contributing factors for CXCL10 up-regulation during infection. In addition, our results showed that a fragment consisting of residues 196-413 in MERS-N is sufficient to up-regulate CXCL10, while the N-terminal domain and serine-arginine (SR)-rich motif of MERS-N do not play a role in this up-regulation.


Assuntos
Quimiocina CXCL10/genética , Infecções por Coronavirus/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Proteínas do Nucleocapsídeo/genética , Células A549 , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Regulação Viral da Expressão Gênica/genética , Interações Hospedeiro-Patógeno/genética , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Domínios Proteicos/genética , Ativação Transcricional/genética
16.
Cell Calcium ; 75: 30-41, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30121440

RESUMO

Middle East Respiratory Syndrome coronavirus (MERS-CoV) infections are associated with a significant mortality rate, and existing drugs show poor efficacy. Identifying novel targets/pathways required for MERS infectivity is therefore important for developing novel therapeutics. As an enveloped virus, translocation through the endolysosomal system provides one pathway for cellular entry of MERS-CoV. In this context, Ca2+-permeable channels within the endolysosomal system regulate both the luminal environment and trafficking events, meriting investigation of their role in regulating processing and trafficking of MERS-CoV. Knockdown of endogenous two-pore channels (TPCs), targets for the Ca2+ mobilizing second messenger NAADP, impaired infectivity in a MERS-CoV spike pseudovirus particle translocation assay. This effect was selective as knockdown of the lysosomal cation channel mucolipin-1 (TRPML1) was without effect. Pharmacological inhibition of NAADP-evoked Ca2+ release using several bisbenzylisoquinoline alkaloids also blocked MERS pseudovirus translocation. Knockdown of TPC1 (biased endosomally) or TPC2 (biased lysosomally) decreased the activity of furin, a protease which facilitates MERS fusion with cellular membranes. Pharmacological or genetic inhibition of TPC1 activity also inhibited endosomal motility impairing pseudovirus progression through the endolysosomal system. Overall, these data support a selective, spatially autonomous role for TPCs within acidic organelles to support MERS-CoV translocation.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Endossomos/virologia , Lisossomos/virologia , Coronavírus da Síndrome Respiratória do Oriente Médio/metabolismo , NADP/análogos & derivados , Benzilisoquinolinas/farmacologia , Linhagem Celular , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Furina/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Canais Iônicos/metabolismo , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , NADP/farmacologia , Reprodutibilidade dos Testes , Glicoproteína da Espícula de Coronavírus/metabolismo , Canais de Sódio Disparados por Voltagem/metabolismo
17.
Sci Rep ; 8(1): 10727, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-30013082

RESUMO

The recurrence of new human cases of Middle East respiratory syndrome coronavirus (MERS-CoV) underscores the need for effective therapeutic countermeasures. Nonhuman primate models are considered the gold standard for preclinical evaluation of therapeutic countermeasures. However, MERS-CoV-induced severe respiratory disease in humans is associated with high viral loads in the lower respiratory tract, which may be difficult to achieve in nonhuman primate models. Considering this limitation, we wanted to ascertain the effectiveness of using a MERS-CoV infectious clone (icMERS-0) previously shown to replicate to higher titers than the wild-type EMC 2012 strain. We observed respiratory disease resulting from exposure to the icMERS-0 strain as measured by CT in rhesus monkeys with concomitant detection of virus antigen by immunohistochemistry. Overall, respiratory disease was mild and transient, resolving by day 30 post-infection. Although pulmonary disease was mild, these results demonstrate for the first time the utility of CT imaging to measure disease elicited by a MERS-CoV infectious clone system in nonhuman primate models.


Assuntos
Infecções por Coronavirus/diagnóstico , Pulmão/diagnóstico por imagem , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Animais , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Modelos Animais de Doenças , Humanos , Processamento de Imagem Assistida por Computador , Pulmão/patologia , Pulmão/virologia , Macaca mulatta , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/isolamento & purificação , Coronavírus da Síndrome Respiratória do Oriente Médio/fisiologia , RNA Viral/isolamento & purificação , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X , Carga Viral/genética , Replicação Viral/genética
18.
Sci Rep ; 8(1): 9778, 2018 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-29950581

RESUMO

Middle East respiratory syndrome (MERS) represents an important respiratory disease accompanied by lethal outcome in one-third of human patients. Recent data indicate that dromedaries represent an important source of infection, although information regarding viral cell tropism and pathogenesis is sparse. In the current study, tissues of eight dromedaries receiving inoculation of MERS-Coronavirus (MERS-CoV) after recombinant Modified-Vaccinia-Virus-Ankara (MVA-S)-vaccination (n = 4), MVA-vaccination (mock vaccination, n = 2) and PBS application (mock vaccination, n = 2), respectively, were investigated. Tissues were analyzed by histology, immunohistochemistry, immunofluorescence, and scanning electron microscopy. MERS-CoV infection in mock-vaccinated dromedaries revealed high numbers of MERS-CoV-nucleocapsid positive cells, T cells, and macrophages within nasal turbinates and trachea at day four post infection. Double immunolabeling demonstrated cytokeratin (CK) 18 expressing epithelial cells to be the prevailing target cell of MERS-CoV, while CK5/6 and CK14 expressing cells did not co-localize with virus. In addition, virus was occasionally detected in macrophages. The acute disease was further accompanied by ciliary loss along with a lack of dipeptidyl peptidase 4 (DPP4), known to mediate virus entry. DPP4 was mainly expressed by human lymphocytes and dromedary monocytes, but overall the expression level was lower in dromedaries. The present study underlines significant species-specific manifestations of MERS and highlights ciliary loss as an important finding in dromedaries. The obtained results promote a better understanding of coronavirus infections, which pose major health challenges.


Assuntos
Dipeptidil Peptidase 4/metabolismo , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Animais , Camelus , Células Cultivadas , Infecções por Coronavirus/metabolismo , Imunofluorescência , Imuno-Histoquímica , Queratina-14/metabolismo , Queratina-18/metabolismo , Queratina-4/metabolismo , Queratina-5/metabolismo , Microscopia Eletrônica de Varredura , Coronavírus da Síndrome Respiratória do Oriente Médio/metabolismo , Coronavírus da Síndrome Respiratória do Oriente Médio/ultraestrutura
19.
Antivir Ther ; 23(7): 617-622, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29923831

RESUMO

BACKGROUND: The effects of convalescent plasma (CP) infusion, one of the treatment options for severe Middle East respiratory syndrome coronavirus (MERS-CoV) infections, have not yet been evaluated. METHODS: Serological responses of CP-infused MERS patients during the 2015 Korean MERS outbreak at a tertiary care centre were evaluated. Serological activity was evaluated with anti-MERS-CoV enzyme-linked immunosorbent assay (ELISA) immunoglobulin (Ig)G, ELISA IgA, immunofluorescence assay IgM and plaque reduction neutralization test (PRNT). Donor plasma and one or two recipient's serum samples per week of illness including one taken the day after each CP infusion were evaluated. For sensitivity and specificity analysis of ELISA IgG in predicting neutralization activity, a data set of 138 previously evaluated MERS-CoV-infected patients was used. RESULTS: Three of thirteen MERS patients with respiratory failure received four CP infusions from convalesced MERS-CoV-infected patients, and only two of them showed neutralizing activity. Donor plasma with a PRNT titre 1:80 demonstrated meaningful serological response after CP infusion, while that with a PRNT titre 1:40 did not. ELISA IgG predicted neutralization activity of a PRNT titre ≥1:80 with more than 95% specificity at a cutoff optical density (OD) ratio of 1.6, and with 100% specificity at an OD ratio of 1.9. CONCLUSIONS: For effective CP infusion in MERS, donor plasma with a neutralization activity of a PRNT titre ≥1:80 should be used. ELISA IgG could substitute for the neutralization test in resource-limited situations.


Assuntos
Anticorpos Antivirais/sangue , Infecções por Coronavirus/terapia , Surtos de Doenças , Soros Imunes/administração & dosagem , Insuficiência Respiratória/terapia , Adulto , Convalescença , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Coronavírus da Síndrome Respiratória do Oriente Médio/efeitos dos fármacos , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Testes de Neutralização , República da Coreia/epidemiologia , Insuficiência Respiratória/epidemiologia , Insuficiência Respiratória/imunologia , Insuficiência Respiratória/virologia , Centros de Atenção Terciária
20.
Lancet Infect Dis ; 18(8): e217-e227, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29680581

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) is a lethal zoonosis that causes death in 35·7% of cases. As of Feb 28, 2018, 2182 cases of MERS-CoV infection (with 779 deaths) in 27 countries were reported to WHO worldwide, with most being reported in Saudi Arabia (1807 cases with 705 deaths). MERS-CoV features prominently in the WHO blueprint list of priority pathogens that threaten global health security. Although primary transmission of MERS-CoV to human beings is linked to exposure to dromedary camels (Camelus dromedarius), the exact mode by which MERS-CoV infection is acquired remains undefined. Up to 50% of MERS-CoV cases in Saudi Arabia have been classified as secondary, occurring from human-to-human transmission through contact with asymptomatic or symptomatic individuals infected with MERS-CoV. Hospital outbreaks of MERS-CoV are a hallmark of MERS-CoV infection. The clinical features associated with MERS-CoV infection are not MERS-specific and are similar to other respiratory tract infections. Thus, the diagnosis of MERS can easily be missed, unless the doctor or health-care worker has a high degree of clinical awareness and the patient undergoes specific testing for MERS-CoV. The largest outbreak of MERS-CoV outside the Arabian Peninsula occurred in South Korea in May, 2015, resulting in 186 cases with 38 deaths. This outbreak was caused by a traveller with undiagnosed MERS-CoV infection who became ill after returning to Seoul from a trip to the Middle East. The traveller visited several health facilities in South Korea, transmitting the virus to many other individuals long before a diagnosis was made. With 10 million pilgrims visiting Saudi Arabia each year from 182 countries, watchful surveillance by public health systems, and a high degree of clinical awareness of the possibility of MERS-CoV infection is essential. In this Review, we provide a comprehensive update and synthesis of the latest available data on the epidemiology, determinants, and risk factors of primary, household, and nosocomial transmission of MERS-CoV, and suggest measures to reduce risk of transmission.


Assuntos
Infecções por Coronavirus/epidemiologia , Infecção Hospitalar , Transmissão de Doença Infecciosa , Características da Família , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Animais , Camelus , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/mortalidade , Surtos de Doenças , Saúde Global , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/isolamento & purificação , Fatores de Risco , Arábia Saudita/epidemiologia , Zoonoses
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA