scholarly journals Two Mutations Were Critical for Bat-to-Human Transmission of Middle East Respiratory Syndrome Coronavirus

2015 ◽  
Vol 89 (17) ◽  
pp. 9119-9123 ◽  
Author(s):  
Yang Yang ◽  
Chang Liu ◽  
Lanying Du ◽  
Shibo Jiang ◽  
Zhengli Shi ◽  
...  
Keyword(s):  
Middle East ◽  
Viral Entry ◽  
Human Cells ◽  
Middle East Respiratory Syndrome ◽  
Intermediate Hosts ◽  
Virus Surface ◽  
Bat Coronavirus ◽  
Do So

To understand how Middle East respiratory syndrome coronavirus (MERS-CoV) transmitted from bats to humans, we compared the virus surface spikes of MERS-CoV and a related bat coronavirus, HKU4. Although HKU4 spike cannot mediate viral entry into human cells, two mutations enabled it to do so by allowing it to be activated by human proteases. These mutations are present in MERS-CoV spike, explaining why MERS-CoV infects human cells. These mutations therefore played critical roles in the bat-to-human transmission of MERS-CoV, either directly or through intermediate hosts.

scholarly journals Middle East Respiratory Syndrome Coronavirus Spike Protein Is Not Activated Directly by Cellular Furin during Viral Entry into Target Cells

2018 ◽  
Vol 92 (19) ◽  
Author(s):  
Shutoku Matsuyama ◽  
Kazuya Shirato ◽  
Miyuki Kawase ◽  
Yutaka Terada ◽  
Kengo Kawachi ◽  
...  
Keyword(s):  
Middle East ◽  
Viral Entry ◽  
Cathepsin L ◽  
Inhibitory Effect ◽  
Middle East Respiratory Syndrome ◽  
Cell Entry ◽  
Target Cells ◽  
Furin Cleavage ◽  
S Protein ◽  
Entry Assay

ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes host cellular proteases to enter cells. A previous report shows that furin, which is distributed mainly in the Golgi apparatus and cycled to the cell surface and endosomes, proteolytically activates the MERS-CoV spike (S) protein following receptor binding to mediate fusion between the viral and cellular membranes. In this study, we reexamined furin usage by MERS-CoV using a real-time PCR-based virus cell entry assay after inhibition of cellular proteases. We found that the furin inhibitor dec-RVKR-CMK blocked entry of MERS-CoV harboring an S protein lacking furin cleavage sites; it even blocked entry into furin-deficient LoVo cells. In addition, dec-RVKR-CMK inhibited not only the enzymatic activity of furin but also those of cathepsin L, cathepsin B, trypsin, papain, and TMPRSS2. Furthermore, a virus cell entry assay and a cell-cell fusion assay provided no evidence that the S protein was activated by exogenous furin. Therefore, we conclude that furin does not play a role in entry of MERS-CoV into cells and that the inhibitory effect of dec-RVKR-CMK is specific for TMPRSS2 and cathepsin L rather than furin. IMPORTANCE Previous studies using the furin inhibitor dec-RVKR-CMK suggest that MERS-CoV utilizes a cellular protease, furin, to activate viral glycoproteins during cell entry. However, we found that dec-RVKR-CMK inhibits not only furin but also other proteases. Furthermore, we found no evidence that MERS-CoV uses furin. These findings suggest that previous studies in the virology field based on dec-RVKR-CMK should be reexamined carefully. Here we describe appropriate experiments that can be used to assess the effect of protease inhibitors on virus cell entry.

scholarly journals Middle East respiratory syndrome coronavirus and bat coronavirus HKU9 both can utilize GRP78 for attachment onto host cells

2018 ◽  
Vol 293 (30) ◽  
pp. 11709-11726 ◽  
Author(s):  
Hin Chu ◽  
Che-Man Chan ◽  
Xi Zhang ◽  
Yixin Wang ◽  
Shuofeng Yuan ◽  
...  
Keyword(s):  
Middle East ◽  
Middle East Respiratory Syndrome ◽  
Host Cells ◽  
Bat Coronavirus

scholarly journals Potential Intermediate Hosts for Coronavirus Transmission: No Evidence of Clade 2c Coronaviruses in Domestic Livestock from Ghana

2019 ◽  
Vol 4 (1) ◽  
pp. 34 ◽  
Author(s):  
Philip El-Duah ◽  
Augustina Sylverken ◽  
Michael Owusu ◽  
Richmond Yeboah ◽  
Jones Lamptey ◽  
...  
Keyword(s):  
Middle East ◽  
Immunofluorescence Assay ◽  
Igg Antibodies ◽  
Intermediate Hosts ◽  
Dromedary Camels ◽  
Pcr Assay ◽  
Livestock Species ◽  
Worldwide Distribution ◽  
Domestic Livestock ◽  
Bat Coronavirus

The emergence of Middle East Respiratory Syndrome Coronavirus (MERS-CoV), nearly a decade ago with worldwide distribution, was believed to be of zoonotic origin from bats with dromedary camels as intermediate hosts. There is a likelihood of other domestic livestock serving as intermediate hosts for this virus. The presence of coronaviruses, closely related to MERS-CoV in Ghanaian bats, presented the opportunity to test the hypothesis of transmissibility of this virus through domestic livestock species. The possible interactions between livestock and bats in 31 household farms were accessed by observation and interviews with farmers. Rectal swabs and serum from cattle, sheep, goats, donkeys, and swine from commercial and household farms were tested for MERS-CoV and a Nycteris sp. bat coronavirus, previously detected in Ghana. A pan-PCR assay to detect clade 2c viruses and recombinant immunofluorescence assay to detect anti-spike IgG antibodies against the target viruses were used. Likely contact between livestock and bats was determined for 13 farms (41.9%) that reported confining their livestock and also observing bats in their homes. Livestock were left unconfined on eight farms (25.8%) that also observed bats roosting in trees close to their homes. No viral RNA or antibodies against the two coronaviruses were detected in any of the livestock species tested. Cattle, sheep, goats, donkeys, and swine are not likely hosts of clade 2c coronaviruses.

scholarly journals Mutations in the Spike Protein of Middle East Respiratory Syndrome Coronavirus Transmitted in Korea Increase Resistance to Antibody-Mediated Neutralization

2018 ◽  
Vol 93 (2) ◽  
Author(s):  
Hannah Kleine-Weber ◽  
Mahmoud Tarek Elzayat ◽  
Lingshu Wang ◽  
Barney S. Graham ◽  
Marcel A. Müller ◽  
...  
Keyword(s):  
Middle East ◽  
Protein Binding ◽  
Receptor Binding ◽  
Viral Entry ◽  
Middle East Respiratory Syndrome ◽  
Spike Protein ◽  
Target Cells ◽  
S Protein ◽  
Hospital Outbreak ◽  
The Republic

ABSTRACT 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.

scholarly journals Interferon Regulatory Factor 3-Mediated Signaling Limits Middle-East Respiratory Syndrome (MERS) Coronavirus Propagation in Cells from an Insectivorous Bat

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 152 ◽  
Author(s):  
Arinjay Banerjee ◽  
Darryl Falzarano ◽  
Noreen Rapin ◽  
Jocelyne Lew ◽  
Vikram Misra
Keyword(s):  
Middle East ◽  
Nuclear Translocation ◽  
Human Cells ◽  
Middle East Respiratory Syndrome ◽  
Poly I:C ◽  
Interferon Response ◽  
Synthetic Analogue ◽  
Post Translational Modifications ◽  
Antiviral Responses ◽  
Interfering Rna

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 (IFNβ) 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 IFNβ in bat cells. Our study demonstrates that innate antiviral signaling in E. fuscus bat cells is resistant to MERS-CoV-mediated subversion.

scholarly journals Ca2+ ions promote fusion of Middle East Respiratory Syndrome coronavirus with host cells and increase infectivity

2019 ◽  
Author(s):  
Marco R. Straus ◽  
Tiffany Tang ◽  
Alex L. Lai ◽  
Annkatrin Flegel ◽  
Miya Bidon ◽  
...  
Keyword(s):  
Middle East ◽  
Viral Entry ◽  
Sequence Similarity ◽  
Isothermal Calorimetry ◽  
Mutant Cell ◽  
Proteolytic Cleavage ◽  
Middle East Respiratory Syndrome ◽  
Host Cells ◽  
Cell Surface Expression ◽  
High Sequence Similarity

AbstractMiddle East respiratory syndrome coronavirus (MERS-CoV) is a major emerging zoonotic infectious disease. Since its first outbreak in 2012, the virus has repeatedly transmitted from camels to humans with 2,468 confirmed cases, causing 851 deaths. To date, there are no efficacious drugs and vaccines against MERS-CoV, increasing its potential to cause a public health emergency. A critical step in the life cycle of MERS-CoV is the fusion with the host cell with its spike (S) protein as main determinant of viral entry. Proteolytic cleavage of S exposes its fusion peptide (FP), which initiates membrane fusion. Previous studies on the related severe acute respiratory syndrome coronavirus (SARS-CoV) FP have shown that calcium (Ca2+) plays an important role for fusogenic activity via a Ca2+ binding pocket with conserved glutamic acid (E) and aspartic acid (D) residues. SARS-CoV and MERS-CoV FP share a high sequence homology and here, we investigated whether Ca2+ is required for MERS-CoV fusion by substituting E and D residues in the MERS-CoV FP with neutrally charged alanines. Upon verifying mutant cell surface expression and proteolytic cleavage, we tested the mutants ability to mediate infection of pseudo-particles (PPs) on host cells without and with Ca2+. Our results demonstrate that intracellular Ca2+ enhances MERS-CoV WT PPs infection by approximately two-fold and that E891 is a crucial residue for Ca2+ interaction. Electron spin resonance revealed that this enhancement could be attributed to Ca2+ increasing MERS-CoV FP fusion-relevant membrane ordering. Intriguingly, isothermal calorimetry titration showed that MERS-CoV FP binds one Ca2+, as opposed to SARS-CoV FP which binds two. Our data suggests that there are significant differences in FP-Ca2+ interactions of MERS-CoV and SARS-CoV FP despite their high sequence similarity and that the number of Ca2+ ions interacting with the FP has implications on the fusion dynamics of the virus.

scholarly journals Potential host range of multiple SARS-like coronaviruses and an improved ACE2-Fc variant that is potent against both SARS-CoV-2 and SARS-CoV-1

2020 ◽  
Author(s):  
Yujun Li ◽  
Haimin Wang ◽  
Xiaojuan Tang ◽  
Danting Ma ◽  
Chengzhi Du ◽  
...  
Keyword(s):  
Host Range ◽  
Viral Entry ◽  
Intermediate Hosts ◽  
Domestic Species ◽  
Entry Inhibitors ◽  
Binding Domains ◽  
Protein Receptor ◽  
Wide Range ◽  
Bat Coronavirus ◽  
Insight Into

SUMMARYThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a currently uncontrolled pandemic and the etiological agent of coronavirus disease 2019 (COVID-19). It is important to study the host range of SARS-CoV-2 because some domestic species might harbor the virus and transmit it back to humans. In addition, insight into the ability of SARS-CoV-2 and SARS-like viruses to utilize animal orthologs of the SARS-CoV-2 receptor ACE2 might provide structural insight into improving ACE2-based viral entry inhibitors. Here we show that ACE2 orthologs of a wide range of domestic and wild animals support entry of SARS-CoV-2, as well as that of SARS-CoV-1, bat coronavirus RaTG13, and a coronavirus isolated from pangolins. Some of these species, including camels, cattle, horses, goats, sheep, pigs, cats, and rabbits may serve as potential intermediate hosts for new human transmission, and rabbits in particular may serve as a useful experimental model of COVID-19. We show that SARS-CoV-2 and SARS-CoV-1 entry could be potently blocked by recombinant IgG Fc-fusion proteins of viral spike protein receptor-binding domains (RBD-Fc) and soluble ACE2 (ACE2-Fc). Moreover, an ACE2-Fc variant, which carries a D30E mutation and has ACE2 truncated at its residue 740 but not 615, outperforms all the other ACE2-Fc variants on blocking entry of both viruses. Our data suggest that RBD-Fc and ACE2-Fc could be used to treat and prevent infection of SARS-CoV-2 and any new viral variants that emerge over the course of the pandemic.

scholarly journals Testing of Middle East Respiratory Syndrome Coronavirus Replication Inhibitors for the Ability To Block Viral Entry

2014 ◽  
Vol 59 (1) ◽  
pp. 742-744 ◽  
Author(s):  
Qi Liu ◽  
Shuai Xia ◽  
Zhiwu Sun ◽  
Qian Wang ◽  
Lanying Du ◽  
...  
Keyword(s):  
Middle East ◽  
Viral Entry ◽  
Middle East Respiratory Syndrome

scholarly journals Discovery of Novel Bat Coronaviruses in South China That Use the Same Receptor as Middle East Respiratory Syndrome Coronavirus

2018 ◽  
Vol 92 (13) ◽  
Author(s):  
Chu-Ming Luo ◽  
Ning Wang ◽  
Xing-Lou Yang ◽  
Hai-Zhou Liu ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Middle East ◽  
South China ◽  
Middle East Respiratory Syndrome ◽  
Epidemiological Surveillance ◽  
Content Type ◽  
Dipeptidyl Peptidase 4 ◽  
Protein Protein Interaction ◽  
Evolutionary Origins ◽  
Bat Coronavirus ◽  
Spike Proteins

ABSTRACTMiddle East respiratory syndrome coronavirus (MERS-CoV) has represented a human health threat since 2012. Although several MERS-related CoVs that belong to the same species as MERS-CoV have been identified from bats, they do not use the MERS-CoV receptor, dipeptidyl peptidase 4 (DPP4). Here, we screened 1,059 bat samples from at least 30 bat species collected in different regions in south China and identified 89 strains of lineage C betacoronaviruses, includingTylonycteris pachypus coronavirus HKU4,Pipistrellus pipistrelluscoronavirus HKU5, and MERS-related CoVs. We sequenced the full-length genomes of two positive samples collected from the great evening bat,Ia io, from Guangdong Province. The two genomes were highly similar and exhibited genomic structures identical to those of other lineage C betacoronaviruses. While they exhibited genome-wide nucleotide identities of only 75.3 to 81.2% with other MERS-related CoVs, their gene-coding regions were highly similar to their counterparts, except in the case of the spike proteins. Further protein-protein interaction assays demonstrated that the spike proteins of these MERS-related CoVs bind to the receptor DPP4. Recombination analysis suggested that the newly discovered MERS-related CoVs have acquired their spike genes from a DPP4-recognizing bat coronavirus HKU4. Our study provides further evidence that bats represent the evolutionary origins of MERS-CoV.IMPORTANCEPrevious studies suggested that MERS-CoV originated in bats. However, its evolutionary path from bats to humans remains unclear. In this study, we discovered 89 novel lineage C betacoronaviruses in eight bat species. We provide evidence of a MERS-related CoV derived from the great evening bat that uses the same host receptor as human MERS-CoV. This virus also provides evidence for a natural recombination event between the bat MERS-related CoV and another bat coronavirus, HKU4. Our study expands the host ranges of MERS-related CoV and represents an important step toward establishing bats as the natural reservoir of MERS-CoV. These findings may lead to improved epidemiological surveillance of MERS-CoV and the prevention and control of the spread of MERS-CoV to humans.

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