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1.
Molecules ; 27(21)2022 Nov 04.
Article in English | MEDLINE | ID: covidwho-2099669

ABSTRACT

Middle East respiratory syndrome coronavirus (MERS-CoV), belonging to the betacoronavirus genus can cause severe respiratory illnesses, accompanied by pneumonia, multiorgan failure, and ultimately death. CoVs have the ability to transgress species barriers and spread swiftly into new host species, with human-to-human transmission causing epidemic diseases. Despite the severe public health threat of MERS-CoV, there are currently no vaccines or drugs available for its treatment. MERS-CoV papain-like protease (PLpro) is a key enzyme that plays an important role in its replication. In the present study, we evaluated the inhibitory activities of doxorubicin (DOX) against the recombinant MERS-CoV PLpro by employing protease inhibition assays. Hydrolysis of fluorogenic peptide from the Z-RLRGG-AMC-peptide bond in the presence of DOX showed an IC50 value of 1.67 µM at 30 min. Subsequently, we confirmed the interaction between DOX and MERS-CoV PLpro by thermal shift assay (TSA), and DOX increased ΔTm by ~20 °C, clearly indicating a coherent interaction between the MERS-CoV PL protease and DOX. The binding site of DOX on MERS-CoV PLpro was assessed using docking techniques and molecular dynamic (MD) simulations. DOX bound to the thumb region of the catalytic domain of the MERS-CoV PLpro. MD simulation results showed flexible BL2 loops, as well as other potential residues, such as R231, R233, and G276 of MERS-CoV PLpro. Development of drug repurposing is a remarkable opportunity to quickly examine the efficacy of different aspects of treating various diseases. Protease inhibitors have been found to be effective against MERS-CoV to date, and numerous candidates are currently undergoing clinical trials to prove this. Our effort follows a in similar direction.


Subject(s)
Middle East Respiratory Syndrome Coronavirus , Humans , Middle East Respiratory Syndrome Coronavirus/metabolism , Papain/chemistry , Peptide Hydrolases/metabolism , Drug Repositioning , Doxorubicin/pharmacology , Doxorubicin/metabolism
3.
Animal Model Exp Med ; 5(5): 401-409, 2022 10.
Article in English | MEDLINE | ID: covidwho-2084982

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), the most consequential pandemic of this century, threatening human health and public safety. SARS-CoV-2 has been continuously evolving through mutation of its genome and variants of concern have emerged. The World Health Organization R&D Blueprint plan convened a range of expert groups to develop animal models for COVID-19, a core requirement for the prevention and control of SARS-CoV-2 pandemic. The animal model construction techniques developed during the SARS-CoV and MERS-CoV pandemics were rapidly deployed and applied in the establishment of COVID-19 animal models. To date, a large number of animal models for COVID-19, including mice, hamsters, minks and nonhuman primates, have been established. Infectious diseases produce unique manifestations according to the characteristics of the pathogen and modes of infection. Here we classified animal model resources around the infection route of SARS-CoV-2, and summarized the characteristics of the animal models constructed via transnasal, localized, and simulated transmission routes of infection.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Cricetinae , Animals , Humans , Mice , SARS-CoV-2 , Pandemics , Middle East Respiratory Syndrome Coronavirus/genetics , Models, Animal
4.
Phys Chem Chem Phys ; 24(41): 25391-25402, 2022 Oct 27.
Article in English | MEDLINE | ID: covidwho-2077132

ABSTRACT

Here, we have carried out a proof-of-concept molecular dynamics (MD) simulation with adaptive tempering in a membrane mimetic environment to study the folding of single-pass membrane peptides. We tested the influenza A M2 viroporin, influenza B M2 viroporin, and protein E from coronaviruses MERS-Cov-2 and SARS-CoV-2 peptides with known experimental secondary structures in membrane bilayers. The two influenza-derived peptides are significantly different in the peptide sequence and secondary structure and more polar than the two coronavirus-derived peptides. Through a total of more than 50 µs of simulation time that could be accomplished in trifluoroethanol (TFE), as a membrane model, we characterized comparatively the folding behavior, helical stability, and helical propensity of these transmembrane peptides that match perfectly their experimental secondary structures, and we identified common motifs that reflect their quaternary organization and known (or not) biochemical function. We showed that BM2 is organized into two structurally distinct parts: a significantly more stable N-terminal half, and a fast-converting C-terminal half that continuously folds and unfolds between α-helical structures and non-canonical structures, which are mostly turns. In AM2, both the N-terminal half and C-terminal half are very flexible. In contrast, the two coronavirus-derived transmembrane peptides are much more stable and fast helix-formers when compared with the influenza ones. In particular, the SARS-derived peptide E appears to be the fastest and most stable helix-former of all the four viral peptides studied, with a helical structure that persists almost without disruption for the whole of its 10 µs simulation. By comparing the results with experimental observations, we benchmarked TFE in studying the conformation of membrane and hydrophobic peptides. This work provided accurate results suggesting a methodology to run long MD simulations and predict structural properties of biologically important membrane peptides.


Subject(s)
COVID-19 , Influenza, Human , Humans , Molecular Dynamics Simulation , Peptides/chemistry , Polytetrafluoroethylene , Protein Folding , Protein Structure, Secondary , SARS-CoV-2 , Solvents , Trifluoroethanol/chemistry , Viroporin Proteins , Influenzavirus B , Middle East Respiratory Syndrome Coronavirus
5.
Int J Mol Sci ; 23(19)2022 Oct 06.
Article in English | MEDLINE | ID: covidwho-2066140

ABSTRACT

The search for an effective anti-viral to inhibit COVID-19 is a challenge for the specialized scientific research community. This work investigated the anti-coronavirus activity for spirooxindole-based phenylsulfone cycloadducts in a single and combination protocols. The newly designed anti-SARS-CoV-2 therapeutics spirooxindoles synthesized by [3 + 2] cycloaddition reactions represent an efficient approach. One-pot multicomponent reactions between phenyl vinyl sulfone, substituted isatins, and amines afforded highly stereoselective anti-SARS-CoV-2 therapeutics spirooxindoles with three stereogenic centers. Herein, the newly synthesized spirooxindoles were assessed individually against the highly pathogenic human coronaviruses and proved to be highly potent and safer. Interestingly, the synergistic effect by combining the potent, tested spirooxindoles resulted in an improved antiviral activity as well as better host-cell safety. Compounds 4i and 4d represented the most potent activity against MERS-CoV with IC50 values of 11 and 23 µM, respectively. Both compounds 4c and 4e showed equipotent activity with the best IC50 against SARS-CoV-2 with values of 17 and 18 µM, respectively, then compounds 4d and 4k with IC50 values of 24 and 27 µM, respectively. Then, our attention oriented to perform a combination protocol as anti-SARS-CoV-2 for the best compounds with a different binding mode and accompanied with different pharmacophores. Combination of compound 4k with 4c and combination of compounds 4k with 4i proved to be more active and safer. Compounds 4k with 4i displayed IC50 = 3.275 µM and half maximal cytotoxic-concentration CC50 = 11832 µM. MD simulation of the most potential compounds as well as in silico ADMET properties were investigated. This study highlights the potential drug-like properties of spirooxindoles as a cocktail anti-coronavirus protocol.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Amines/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Humans , Molecular Docking Simulation , SARS-CoV-2
6.
Transbound Emerg Dis ; 69(5): e2122-e2131, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-2053007

ABSTRACT

The ongoing enzootic circulation of the Middle East respiratory syndrome coronavirus (MERS-CoV) in the Middle East and North Africa is increasingly raising the concern about the possibility of its recombination with other human-adapted coronaviruses, particularly the pandemic SARS-CoV-2. We aim to provide an updated picture about ecological niches of MERS-CoV and associated socio-environmental drivers. Based on 356 confirmed MERS cases with animal contact reported to the WHO and 63 records of animal infections collected from the literature as of 30 May 2020, we assessed ecological niches of MERS-CoV using an ensemble model integrating three machine learning algorithms. With a high predictive accuracy (area under receiver operating characteristic curve = 91.66% in test data), the ensemble model estimated that ecologically suitable areas span over the Middle East, South Asia and the whole North Africa, much wider than the range of reported locally infected MERS cases and test-positive animal samples. Ecological suitability for MERS-CoV was significantly associated with high levels of bareland coverage (relative contribution = 30.06%), population density (7.28%), average temperature (6.48%) and camel density (6.20%). Future surveillance and intervention programs should target the high-risk populations and regions informed by updated quantitative analyses.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Animals , COVID-19/epidemiology , COVID-19/veterinary , Camelus , Humans , Machine Learning , SARS-CoV-2
7.
Emerg Microbes Infect ; 11(1): 2529-2543, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2051169

ABSTRACT

Autophagy, a cellular surveillance mechanism, plays an important role in combating invading pathogens. However, viruses have evolved various strategies to disrupt autophagy and even hijack it for replication and release. Here, we demonstrated that Middle East respiratory syndrome coronavirus (MERS-CoV) non-structural protein 1(nsp1) induces autophagy but inhibits autophagic activity. MERS-CoV nsp1 expression increased ROS and reduced ATP levels in cells, which activated AMPK and inhibited the mTOR signalling pathway, resulting in autophagy induction. Meanwhile, as an endonuclease, MERS-CoV nsp1 downregulated the mRNA of lysosome-related genes that were enriched in nsp1-located granules, which diminished lysosomal biogenesis and acidification, and inhibited autophagic flux. Importantly, MERS-CoV nsp1-induced autophagy can lead to cell death in vitro and in vivo. These findings clarify the mechanism by which MERS-CoV nsp1-mediated autophagy regulation, providing new insights for the prevention and treatment of the coronavirus.


Subject(s)
Middle East Respiratory Syndrome Coronavirus , Middle East Respiratory Syndrome Coronavirus/physiology , AMP-Activated Protein Kinases/metabolism , Reactive Oxygen Species/metabolism , RNA, Messenger/metabolism , Lysosomes/metabolism , Autophagy , Endonucleases/metabolism , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , Adenosine Triphosphate/metabolism
8.
Cell Rep Med ; 3(10): 100774, 2022 10 18.
Article in English | MEDLINE | ID: covidwho-2050073

ABSTRACT

"Pan-coronavirus" antivirals targeting conserved viral components can be designed. Here, we show that the rationally engineered H84T-banana lectin (H84T-BanLec), which specifically recognizes high mannose found on viral proteins but seldom on healthy human cells, potently inhibits Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (including Omicron), and other human-pathogenic coronaviruses at nanomolar concentrations. H84T-BanLec protects against MERS-CoV and SARS-CoV-2 infection in vivo. Importantly, intranasally and intraperitoneally administered H84T-BanLec are comparably effective. Mechanistic assays show that H84T-BanLec targets virus entry. High-speed atomic force microscopy depicts real-time multimolecular associations of H84T-BanLec dimers with the SARS-CoV-2 spike trimer. Single-molecule force spectroscopy demonstrates binding of H84T-BanLec to multiple SARS-CoV-2 spike mannose sites with high affinity and that H84T-BanLec competes with SARS-CoV-2 spike for binding to cellular ACE2. Modeling experiments identify distinct high-mannose glycans in spike recognized by H84T-BanLec. The multiple H84T-BanLec binding sites on spike likely account for the drug compound's broad-spectrum antiviral activity and the lack of resistant mutants.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Humans , SARS-CoV-2 , Lectins/pharmacology , Mannose/pharmacology , Angiotensin-Converting Enzyme 2 , Spike Glycoprotein, Coronavirus/pharmacology , Antiviral Agents/pharmacology
9.
Methods Mol Biol ; 2556: 243-271, 2022.
Article in English | MEDLINE | ID: covidwho-2047965

ABSTRACT

Ongoing seasonal HCoV-OC43 and HCoV-HKU1 (common cold), an ongoing zoonotic infection of highly lethal MERS-CoV in humans (MERS disease), and an ongoing pandemic SARS-CoV-2 (COVID-19) with high mutability giving some variants causing severe illness and death have been reported to attach to sialyl receptors via their spike (S) glycoproteins and via additional short spikes, hemagglutinin-esterase (HE) glycoproteins, for HCoV-OC43 and HCoV-HKU1. There is lack of zoonotic viruses that are origins of HCoV-HKU1 and the first recorded pandemic CoV (SARS-CoV-2) for studies. In this chapter, we review current knowledge of the roles of sialyl glycans in infections with these viruses in distinct infection stages. Determination of the similarities and differences in roles of sialyl glycans in infections with these viruses could lead to a better understanding of the pathogenesis and transmission that is essential for combating infections with CoVs that recognize sialyl glycans.


Subject(s)
COVID-19 , Coronavirus OC43, Human , Middle East Respiratory Syndrome Coronavirus , Esterases , Hemagglutinins , Humans , Polysaccharides , SARS-CoV-2
10.
Viruses ; 14(10)2022 09 27.
Article in English | MEDLINE | ID: covidwho-2043992

ABSTRACT

Humans interact with virus-infected animal hosts, travel globally, and maintain social networks that allow for novel viruses to emerge and develop pandemic potential. There are key lessons-learned from the coronavirus diseases 2019 (COVID-19) pandemic that blood operators can apply to the next pandemic. Warning signals to the COVID-19 pandemic included outbreaks of Severe acute respiratory syndrome-related coronavirus-1 (SARS-CoV-1) and Middle East respiratory syndrome-related coronavirus (MERS-CoV) in the prior two decades. It will be critical to quickly determine whether there is a risk of blood-borne transmission of a new pandemic virus. Prior to the next pandemic blood operators should be prepared for changes in activities, policies, and procedures at all levels of the organization. Blood operators can utilize "Plan-Do-Study-Act" cycles spanning from: vigilance for emerging viruses, surveillance activities and studies, operational continuity, donor engagement and trust, and laboratory testing if required. Occupational health and donor safety issues will be key areas of focus even if the next pandemic virus is not transfusion transmitted. Blood operators may also be requested to engage in new activities such as the development of therapeutics or supporting public health surveillance activities. Activities such as scenario development, tabletop exercises, and drills will allow blood operators to prepare for the unknowns of the next pandemic.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , SARS Virus , Animals , Humans , Pandemics/prevention & control , COVID-19/epidemiology , SARS-CoV-2
11.
Virologie (Montrouge) ; 26(4): 283-302, 2022 07 01.
Article in French | MEDLINE | ID: covidwho-2039521

ABSTRACT

For a large proportion of mankind, the word coronavirus only became a reality in the year 2020, as it was the cause of one of the worst pandemics of the last two centuries. Nevertheless, well before this ominous moment, human coronaviruses (HCoV) were well characterized respiratory pathogens since the 1960s. The most recent discovery of SARS-CoV and MERS-CoV showed that coronaviruses have a pandemic potential with important consequences. With the COVID-19 pandemic caused by SARS-CoV-2, this potential is now certain. Moreover, accumulating evidence support an association between coronaviruses and extra-respiratory pathologies, in particular of the central and peripheral nervous system. Linked or not with a neuro-invasive and neurotropic potential, it is now clear that coronaviruses can be associated with the development of neurological disorders.


Pour une grande partie de l'humanité, le terme coronavirus n'est devenu réalité qu'au début de l'année 2020, associé à une des plus importantes pandémies des deux derniers siècles. Pourtant, bien avant ce moment fatidique, les coronavirus humains (HCoV) étaient bien caractérisés en tant que pathogènes respiratoires depuis la fin des années 1960. Depuis le début du XXIe siècle, deux autres coronavirus pouvant infecter l'humain (SARS-CoV et MERS-CoV), ont montré que ces virus avaient un potentiel pandémique pouvant entraîner des conséquences importantes. Avec la survenue de la pandémie de Covid-19 créée par le SARS-CoV-2, ce potentiel ne fait aujourd'hui plus aucun doute. De plus, un nombre grandissant d'études supporte l'idée d'une association entre les coronavirus et diverses pathologies extra-respiratoires, en particulier au niveau des systèmes nerveux central et périphérique. Liés ou non à un véritable potentiel neuro-invasif et neurotrope, il apparaît maintenant de façon claire que les coronavirus peuvent être associés au développement de divers désordres neurologiques.


Subject(s)
COVID-19 , Common Cold , Humans , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , SARS-CoV-2
12.
PLoS Pathog ; 18(9): e1010834, 2022 09.
Article in English | MEDLINE | ID: covidwho-2039449

ABSTRACT

No vaccines or specific antiviral drugs are authorized against Middle East respiratory syndrome coronavirus (MERS-CoV) despite its high mortality rate and prevalence in dromedary camels. Since 2012, MERS-CoV has been causing sporadic zoonotic infections in humans, which poses a risk of genetic evolution to become a pandemic virus. MERS-CoV genome encodes five accessory proteins, 3, 4a, 4b, 5 and 8b for which limited information is available in the context of infection. This work describes 4b as a virulence factor in vivo, since the deletion mutant of a mouse-adapted MERS-CoV-Δ4b (MERS-CoV-MA-Δ4b) was completely attenuated in a humanized DPP4 knock-in mouse model, resulting in no mortality. Attenuation in the absence of 4b was associated with a significant reduction in lung pathology and chemokine expression levels at 4 and 6 days post-infection, suggesting that 4b contributed to the induction of lung inflammatory pathology. The accumulation of 4b in the nucleus in vivo was not relevant to virulence, since deletion of its nuclear localization signal led to 100% mortality. Interestingly, the presence of 4b protein was found to regulate autophagy in the lungs of mice, leading to upregulation of BECN1, ATG3 and LC3A mRNA. Further analysis in MRC-5 cell line showed that, in the context of infection, MERS-CoV-MA 4b inhibited autophagy, as confirmed by the increase of p62 and the decrease of ULK1 protein levels, either by direct or indirect mechanisms. Together, these results correlated autophagy activation in the absence of 4b with downregulation of a pathogenic inflammatory response, thus contributing to attenuation of MERS-CoV-MA-Δ4b.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Animals , Antiviral Agents , Autophagy-Related Protein-1 Homolog , Camelus/genetics , Dipeptidyl Peptidase 4/genetics , Humans , Lung , Mice , Nuclear Localization Signals , RNA, Messenger , Virulence Factors/genetics
13.
mBio ; 13(5): e0241522, 2022 Oct 26.
Article in English | MEDLINE | ID: covidwho-2038243

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has killed over 6 million individuals worldwide and continues to spread in countries where vaccines are not yet widely available or its citizens are hesitant to become vaccinated. Therefore, it is critical to unravel the molecular mechanisms that allow SARS-CoV-2 and other coronaviruses to infect and overtake the host machinery of human cells. Coronavirus replication triggers endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR), a key host cell pathway widely believed to be essential for viral replication. We examined the master UPR sensor IRE1α kinase/RNase and its downstream transcription factor effector XBP1s, which is processed through an IRE1α-mediated mRNA splicing event, in human lung-derived cells infected with betacoronaviruses. We found that human respiratory coronavirus OC43 (HCoV-OC43), Middle East respiratory syndrome coronavirus (MERS-CoV), and murine coronavirus (MHV) all induce ER stress and strongly trigger the kinase and RNase activities of IRE1α as well as XBP1 splicing. In contrast, SARS-CoV-2 only partially activates IRE1α through autophosphorylation, but its RNase activity fails to splice XBP1. Moreover, while IRE1α was dispensable for replication in human cells for all coronaviruses tested, it was required for maximal expression of genes associated with several key cellular functions, including the interferon signaling pathway, during SARS-CoV-2 infection. Our data suggest that SARS-CoV-2 actively inhibits the RNase of autophosphorylated IRE1α, perhaps as a strategy to eliminate detection by the host immune system. IMPORTANCE SARS-CoV-2 is the third lethal respiratory coronavirus, after MERS-CoV and SARS-CoV, to emerge this century, causing millions of deaths worldwide. Other common coronaviruses such as HCoV-OC43 cause less severe respiratory disease. Thus, it is imperative to understand the similarities and differences among these viruses in how each interacts with host cells. We focused here on the inositol-requiring enzyme 1α (IRE1α) pathway, part of the host unfolded protein response to virus-induced stress. We found that while MERS-CoV and HCoV-OC43 fully activate the IRE1α kinase and RNase activities, SARS-CoV-2 only partially activates IRE1α, promoting its kinase activity but not RNase activity. Based on IRE1α-dependent gene expression changes during infection, we propose that SARS-CoV-2 prevents IRE1α RNase activation as a strategy to limit detection by the host immune system.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Animals , Mice , Humans , Endoribonucleases/genetics , Endoribonucleases/metabolism , Endoplasmic Reticulum Stress/genetics , SARS-CoV-2/genetics , Inositol , Protein Serine-Threonine Kinases/genetics , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/metabolism , Ribonucleases/genetics , Transcription Factors , RNA, Messenger , Lung/metabolism , Interferons , X-Box Binding Protein 1/genetics
14.
Viruses ; 14(9)2022 09 18.
Article in English | MEDLINE | ID: covidwho-2033152

ABSTRACT

The ongoing spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused hundreds of millions of cases and millions of victims worldwide with serious consequences to global health and economies. Although many vaccines protecting against SARS-CoV-2 are currently available, constantly emerging new variants necessitate the development of alternative strategies for prevention and treatment of COVID-19. Inhibitors that target the main protease (Mpro) of SARS-CoV-2, an essential enzyme that promotes viral maturation, represent a key class of antivirals. Here, we showed that a peptidomimetic compound with benzothiazolyl ketone as warhead, YH-53, is an effective inhibitor of SARS-CoV-2, SARS-CoV, and MERS-CoV Mpros. Crystal structures of Mpros from SARS-CoV-2, SARS-CoV, and MERS-CoV bound to the inhibitor YH-53 revealed a unique ligand-binding site, which provides new insights into the mechanism of inhibition of viral replication. A detailed analysis of these crystal structures defined the key molecular determinants required for inhibition and illustrate the binding mode of Mpros from other coronaviruses. In consideration of the important role of Mpro in developing antivirals against coronaviruses, insights derived from this study should add to the design of pan-coronaviral Mpro inhibitors that are safer and more effective.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Peptidomimetics , Antiviral Agents/chemistry , Benzothiazoles/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases , Cysteine Endopeptidases/metabolism , Humans , Ketones , Ligands , Peptide Hydrolases , Protease Inhibitors/chemistry , SARS-CoV-2
15.
Virus Res ; 321: 198925, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2031740

ABSTRACT

Human coronaviruses (HCoVs) are important human pathogens, as exemplified by the current SARS-CoV-2 pandemic. While the ability of type I interferons (IFNs) to limit coronavirus replication has been established, the ability of double-stranded (ds)RNA, a potent IFN inducer, to inhibit coronavirus replication when conjugated to a nanoparticle is largely unexplored. Additionally, the number of IFN competent cell lines that can be used to study coronaviruses in vitro are limited. In the present study, we show that poly inosinic: poly cytidylic acid (pIC), when conjugated to a phytoglycogen nanoparticle (pIC+NDX) is able to protect IFN-competent human lung fibroblasts (HEL-299 cells) from infection with different HCoV species. HEL-299 was found to be permissive to HCoV-229E, -OC43 and MERS-CoV-GFP but not to HCoV-NL63 or SARS-CoV-2. Further investigation revealed that HEL-299 does not contain the required ACE2 receptor to enable propagation of both HCoV-NL63 and SARS-CoV-2. Following 24h exposure, pIC+NDX was observed to stimulate a significant, prolonged increase in antiviral gene expression (IFNß, CXCL10 and ISG15) when compared to both NDX alone and pIC alone. This antiviral response translated into complete protection against virus production, for 4 days or 7 days post treatment with HCoV-229E or -OC43 when either pre-treated for 6h or 24h respectively. Moreover, the pIC+NDX combination also provided complete protection for 2d post infection when HEL-299 cells were infected with MERS-CoV-GFP following a 24h pretreatment with pIC+NDX. The significance of this study is two-fold. Firstly, it was revealed that HEL-299 cells can effectively be used as an IFN-competent model system for in vitro analysis of MERS-CoV. Secondly, pIC+NDX acts as a powerful inducer of type I IFNs in HEL-299, to levels that provide complete protection against coronavirus replication. This suggests an exciting and novel area of investigation for antiviral therapies that utilize innate immune stimulants. The results of this study will help to expand the range of available tools scientists have to investigate, and thus further understand, human coronaviruses.


Subject(s)
COVID-19 , Coronavirus 229E, Human , Coronavirus NL63, Human , Interferon Type I , Middle East Respiratory Syndrome Coronavirus , Nanoparticles , Angiotensin-Converting Enzyme 2 , Antiviral Agents/pharmacology , Coronavirus 229E, Human/genetics , Cytidine Monophosphate , Humans , RNA , SARS-CoV-2
16.
Turk J Med Sci ; 52(4): 910-916, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-2026909

ABSTRACT

BACKGROUND: Middle East respiratory syndrome (MERS) is a zoonotic viral disease transmitted from dromedaries to humans. To date, more than 1500 cases of MERS have been reported and 80% of all cases have occurred in the Kingdom of Saudi Arabia (KSA). This cross-sectional study was carried out to figure out the rate of infection among humans and dromedary camels and to explore the risk factors. METHODS: This study was conducted in Diyala Province, Iraq for the period from August 2017 to October 2018. Human subjects included 90 participants; 34 (37.8%) were females and 56 (62.2%) were males. Additionally, 90 dromedary camels were also included, 50 (55.6%) males and 40 (44.4%) females. Serum samples from subjects were collected and tested for the presence of anti-MERS-coronavirus (CoV) immunoglobulin g (IgG). RESULTS: The results revealed that 46 (51.1%) of human subjects were positive for anti-MERS-CoV IgG, (95% confidence interval (CI) for the prevalence rate 40.9-61.3) with a mean titer of anti-MERS-CoV IgG antibodies (Ab) of 81.2 U/mL. The anti-MERS-CoV IgG positivity rate was insignificantly higher, but the mean of anti-MERS-CoV IgG titer was significantly higher among females (p = 0.12 and p < 0.004, respectively). Furthermore, the anti-MERS-CoV IgG positivity rate and Ab titer were significantly higher among those people who visited KSA for Hajj or Umrah (p < 0.001 and p < 0.001, respectively). In camels, 81 (90.0%) were positive for anti-MERS-CoV IgG, (95% CI for the prevalence rate 82.5-94.9), with a mean titer of 99.8 U/mL. DISCUSSION: The MERS-CoV infection rate was high among both Iraqi humans and dromedary camels. Further confirmatory studies are needed, and setting up of national precaution program is essential.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Male , Animals , Female , Humans , Camelus , Cross-Sectional Studies , Iraq/epidemiology , Antibodies, Viral , Coronavirus Infections/epidemiology , Immunoglobulin G
17.
Front Immunol ; 13: 963023, 2022.
Article in English | MEDLINE | ID: covidwho-2022747

ABSTRACT

The COVID-19 pandemic response has shown how vaccine platform technologies can be used to rapidly and effectively counteract a novel emerging infectious disease. The speed of development for mRNA and vector-based vaccines outpaced those of subunit vaccines, however, subunit vaccines can offer advantages in terms of safety and stability. Here we describe a subunit vaccine platform technology, the molecular clamp, in application to four viruses from divergent taxonomic families: Middle Eastern respiratory syndrome coronavirus (MERS-CoV), Ebola virus (EBOV), Lassa virus (LASV) and Nipah virus (NiV). The clamp streamlines subunit antigen production by both stabilising the immunologically important prefusion epitopes of trimeric viral fusion proteins while enabling purification without target-specific reagents by acting as an affinity tag. Conformations for each viral antigen were confirmed by monoclonal antibody binding, size exclusion chromatography and electron microscopy. Notably, all four antigens tested remained stable over four weeks of incubation at 40°C. Of the four vaccines tested, a neutralising immune response was stimulated by clamp stabilised MERS-CoV spike, EBOV glycoprotein and NiV fusion protein. Only the clamp stabilised LASV glycoprotein precursor failed to elicit virus neutralising antibodies. MERS-CoV and EBOV vaccine candidates were both tested in animal models and found to provide protection against viral challenge.


Subject(s)
COVID-19 , Middle East Respiratory Syndrome Coronavirus , Viral Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , Humans , Pandemics , Spike Glycoprotein, Coronavirus , Technology , Vaccines, Subunit
18.
Vet Res ; 53(1): 67, 2022 Sep 02.
Article in English | MEDLINE | ID: covidwho-2009459

ABSTRACT

Middle East respiratory syndrome coronavirus (MERS-CoV) poses a serious threat to public health. Here, we established an ex vivo alpaca tracheal explant (ATE) model using an air-liquid interface culture system to gain insights into MERS-CoV infection in the camelid lower respiratory tract. ATE can be infected by MERS-CoV, being 103 TCID50/mL the minimum viral dosage required to establish a productive infection. IFNs and antiviral ISGs were not induced in ATE cultures in response to MERS-CoV infection, strongly suggesting that ISGs expression observed in vivo is rather a consequence of the IFN induction occurring in the nasal mucosa of camelids.


Subject(s)
Camelids, New World , Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Animals , Antiviral Agents , Bronchi , Coronavirus Infections/veterinary , Middle East Respiratory Syndrome Coronavirus/physiology
19.
Curr Opin Virol ; 52: 192-202, 2022 02.
Article in English | MEDLINE | ID: covidwho-1578659

ABSTRACT

The emergence of zoonotic viral diseases in humans commonly reflects exposure to mammalian wildlife. Bats (order Chiroptera) are arguably the most important mammalian reservoir for zoonotic viruses, with notable examples including Severe Acute Respiratory Syndrome coronaviruses 1 and 2, Middle East Respiratory Syndrome coronavirus, henipaviruses and lyssaviruses. Herein, we outline our current knowledge on the diversity of bat viromes, particularly through the lens of metagenomic next-generation sequencing and in the context of disease emergence. A key conclusion is that although bats harbour abundant virus diversity, the vast majority of bat viruses have not emerged to cause disease in new hosts such that bats are better regarded as critical but endangered components of global ecosystems.


Subject(s)
Chiroptera , Middle East Respiratory Syndrome Coronavirus , Animals , Disease Reservoirs , Ecosystem , Humans , Phylogeny , Virome , Zoonoses
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