Middle East Respiratory Syndrome Coronavirus Research Articles

MiRNAs: Key Molecules in the Immunopathogenesis of Betacoronaviruses

A series of patients hospitalized with acute respiratory disease was reported in Wuhan, Hubei Province, China, in December 2019. Many patients have had direct or indirect links with the Huanan Seafood Wholesale Market, Wuhan. This is the prologue to the ongoing pandemic of Coronavirus Disease 2019 (COVID-19) that has affected more than 150 countries and over 250,000 people worldwide, killing thousands of people. The pandemic has once again drawn public attention to the coronaviruses that developed epidemics in China (2002) and Saudi Arabia (2012). Given the structural and phylogenetic similarity of the 2019 novel coronavirus (2019-nCoV) with the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), the results of recent studies have been combined with new findings to complete one of the strangest pneumonia puzzles in the human history. Coronaviruses establish extremely complex interactions with the immune system, especially in order to evade immune responses. Undoubtedly, increasing our knowledge of the immunopathogenesis of diseases caused by these viruses will eventually lead to more effective treatment and diagnosis. Non-coding RNAs (ncRNAs) are among the leading immune response regulators. MicroRNAs (miRNAs) play an important role in the expression and regulation of both innate and adaptive immune responses and in many immune disorders from autoimmunity to cancer and allergies. Our understanding of the functions of human and viral miRNAs in the pathogenesis of many viruses has increased in recent years. Accordingly, the present review article aims to review studies evaluating the role of miRNAs in the pathogenesis of other Betacoronaviruses. The results of these studies, given the similarity of viruses within the family Coronaviridae, could be helpful for future research on SARS-CoV-2.

Saudi Arabia's Middle East respiratory syndrome Coronavirus (MERS-CoV) outbreak: consequences, reactions, and takeaways.

Middle East respiratory syndrome (MERS) is a viral illness caused by the MERS-Coronavirus (MERS-CoV) that was first identified in Saudi Arabia in 2012. Saudi Arabia has reported most global MERS-CoV cases and deaths, with periodic outbreaks in other countries. This review aims to provide a comprehensive overview of the 2023 MERS-CoV outbreak in Saudi Arabia, including its epidemiology, public health response, impact, and lessons learned. This study utilized a narrative review approach, drawing on published literature and data from sources such as the WHO and the Centers for Disease Control and Prevention. The 2023 outbreak was centered in the Riyadh region, with 312 confirmed cases and 97 deaths reported. MERS-CoV primarily spreads from dromedary camels to humans, with human-to-human transmission, especially in healthcare settings. The outbreak exhibited seasonal and spatial trends, with most cases during camel calving season and in rural areas with high camel populations. The Saudi Ministry of Health implemented a multi-faceted response, including enhancing surveillance, improving infection prevention, providing clinical support, and conducting risk communication. Over time, the response showed a decline in the number of cases and deaths, indicating its effectiveness. The outbreak has significant public health, economic, and social impacts, underscoring the ongoing threat of emerging zoonotic diseases. Key lessons include early case detection, efficient infection control, vaccine and treatment development, public engagement, and strengthening of regional and global collaboration to mitigate future outbreaks and safeguard public health.

Severity of COVID-19 in Pregnant Women: A Review on the Potential Role of Regulatory T Cells.

As a physiological condition, pregnancy may cause temporary alterations in the hematological, cardiopulmonary, and immune responses, affecting the maternal susceptibility to viral infections. Pregnant women are vulnerable to infection with the influenza A virus, hepatitis E virus, MERS CoV, and SARS CoV. The agent of Coronavirus disease (COVID-19) is the SARS coronavirus (SARS CoV-2), which affects the cells upon binding to the angiotensin-converting enzyme-2 (ACE2). However, ACE2 expression is elevated in the placental tissue. However, surprisingly, COVID-19 infection in pregnant women tends to have a lower severity and mortality. Therefore, it is interesting to find the immunological mechanisms related to the severity of COVID-19 in pregnancy. Regulatory T cells (Tregs) are a subset of CD4+T cells that may play a central role in maintaining maternal tolerance by regulating immune responses. Pregnancy-induced Tregs are developed to control immune responses against paternal antigens expressed by the semi-allograft fetus. The role of uncontrolled immune responses in COVID-19 pathogenesis has already been identified. This review provides insight into whether pregnancy- induced regulatory T-cell functions could influence the severity of COVID-19 infection during pregnancy.

A Structural Comparison of Oral SARS-CoV-2 Drug Candidate Ibuzatrelvir Complexed with the Main Protease (Mpro) of SARS-CoV-2 and MERS-CoV.

Ibuzatrelvir (1) was recently disclosed and patented by Pfizer for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has received fast-track status from the USA Food and Drug Administration (FDA) and has entered phase III clinical trials as a possible replacement for Paxlovid. Like nirmatrelvir (2) in Paxlovid, this orally active drug candidate is designed to target viral main proteases (Mpro) through reversible covalent interaction of its nitrile warhead with the active site thiol of the chymotrypsin-like cysteine protease (3CL protease). Inhibition of Mpro hinders the processing of the proteins essential for viral replication in vivo. However, ibuzatrelvir apparently does not require ritonavir (3), which is coadministered in Paxlovid to block human oxidative metabolism of nirmatrelvir. Here, we report the crystal structure of the complex of ibuzatrelvir with the active site of SARS-CoV-2 Mpro at 2.0 Å resolution. In addition, we show that ibuzatrelvir also potently inhibits the Mpro of Middle East respiratory syndrome-related coronavirus (MERS-CoV), which is fortunately not widespread but can be dangerously lethal (∼36% mortality). Co-crystal structures show that the binding mode of the drug to both active sites is similar and that the trifluoromethyl group of the inhibitor fits precisely into a critical S2 substrate binding pocket of the main proteases. However, our results also provide a rationale for the differences in potency of ibuzatrelvir for these two proteases due to minor differences in the substrate preferences leading to a weaker H-bond network in MERS-CoV Mpro. In addition, we examined the reversibility of compound binding to both proteases, which is an important parameter in reducing off-target effects as well as the potential immunogenicity. The crystal structures of the ibuzatrelvir complexes with Mpro of SARS-CoV-2 and of MERS-CoV will further assist drug design for coronaviral infections in humans and animals.

A One Health Perspective on Camel Meat Hygiene and Zoonoses: Insights from a Decade of Research in the Middle East.

The purpose of this review was to investigatethe microbial and chemical safety of camel meat and the zoonotic diseases associated with camels in the Middle East over the past decade, emphasizing the crucial role of a One Health approach. By systematically analyzing recent studies (in the past decade, from 2014), we assessed pathogen prevalence, contamination with heavy metals and pesticide residues, and the impact of zoonotic diseases like Middle East respiratory syndrome coronavirus (MERS-CoV). The findings revealed significant variability in pathogen prevalence, with the frequent detection of traditional foodborne pathogens (e.g., Salmonella and E. coli O157), as well as antibiotic-resistant strains like methicillin-resistant and vancomycin-resistant Staphylococcus aureus and extended-spectrum β-lactamase (ESBL)-producing E. coli, underscoring the need for stringent antibiotic use policies and robust food safety measures. Additionally, the review highlighted substantial contamination of camel meat with heavy metals and pesticide residues, posing significant public health concerns that necessitate stringent regulatory measures and regular monitoring. The persistent occurrence of zoonotic diseases, particularly MERS-CoV, along with other threats like trypanosomiasis, brucellosis, and Clostridium perfringens, emphasizes the importance of strengthening ongoing surveillance. Enhancing investment in diagnostic infrastructures, training programs, and planning capabilities is crucial to address these issues at the camel-human interface in the Middle East. Adopting a One Health perspective is vital to ensuring the safety and quality of camel meat and managing zoonotic risks effectively to ultimately safeguard public health and promote sustainable livestock practices.

Designing a Multi-Epitope Vaccine Candidate to MERS-CoV: An in silico Approach

Background. Middle East Respiratory Syndrome Coronavirus (MERS-CoV), associated with severe respiratory illness, originates from the Middle East region. The virus is transmitted from animals to humans, with the dromedary camel serving as a significant reservoir. The virus's high fatality rate has spurred research into vaccine development and therapeutics. Objective. This study aimed to employ an in silico approach to design a potential vaccine candidate against MERS-CoV, focusing on the M protein as an antigen. Methods. The FASTA sequence of M protein was used to predict B cell and major histocompatibility complex class I and class II epitopes. The best epitopes were selected from these predicted epitopes. The vaccine candi­date's construct consisted of epitopes, linkers, and a tag. The sequence of the vaccine candidate's construct, consisting of 390 amino acids, was back-translated, optimized, and then inserted into a plasmid for cloning and expression using SnapGene. The 3D structure of the vaccine candidate is docked with TLR-4 receptor. Molecular dynamics simulation was run for this docked complex using GROMACS gmx, version 2021.4. Results. Through computational modeling and analysis, we developed a novel vaccine candidate with pro­mising structural and functional properties. Our results suggest that the designed vaccine candidate has the potential to induce a robust immune response. Conclusions. This in silico approach presents a promising MERS-CoV vaccine candidate designed to trigger both humoral and cellular immune responses. This candidate holds the potential to provide broad-spectrum protection against MERS-CoV.

Novel Pan-Coronavirus 3CL Protease Inhibitor MK-7845: Biological and Pharmacological Profiling.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) continues to be a global threat due to its ability to evolve and generate new subvariants, leading to new waves of infection. Additionally, other coronaviruses like Middle East respiratory syndrome coronavirus (MERS-CoV, formerly known as hCoV-EMC), which first emerged in 2012, persist and continue to present a threat of severe illness to humans. The continued identification of novel coronaviruses, coupled with the potential for genetic recombination between different strains, raises the possibility of new coronavirus clades of global concern emerging. As a result, there is a pressing need for pan-CoV therapeutic drugs and vaccines. After the extensive optimization of an HCV protease inhibitor screening hit, a novel 3CLPro inhibitor (MK-7845) was discovered and subsequently profiled. MK-7845 exhibited nanomolar in vitro potency with broad spectrum activity against a panel of clinical SARS-CoV-2 subvariants and MERS-CoV. Furthermore, when administered orally, MK-7845 demonstrated a notable reduction in viral burdens by >6 log orders in the lungs of transgenic mice infected with SARS-CoV-2 (K18-hACE2 mice) and MERS-CoV (K18-hDDP4 mice).

Mutation of a highly conserved isoleucine residue in loop 2 of several β-coronavirus macrodomains indicates that enhanced ADP-ribose binding is detrimental to infection.

All coronaviruses (CoVs) encode for a conserved macrodomain (Mac1) located in nonstructural protein 3 (nsp3). Mac1 is an ADP-ribosylhydrolase that binds and hydrolyzes mono-ADP-ribose from target proteins. Previous work has shown that Mac1 is important for virus replication and pathogenesis. Within Mac1, there are several regions that are highly conserved across CoVs, including the GIF (glycine-isoleucine-phenylalanine) motif. To determine how the biochemical activities of these residues impact CoV replication, the isoleucine and the phenylalanine residues were mutated to alanine (I-A/F-A) in both recombinant Mac1 proteins and recombinant CoVs, including murine hepatitis virus (MHV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The F-A mutant proteins had ADP-ribose binding and/or hydrolysis defects that led to attenuated replication and pathogenesis in cell culture and mice. In contrast, the I-A mutations had normal enzyme activity and enhanced ADP-ribose binding. Despite increased ADP-ribose binding, I-A mutant MERS-CoV and SARS-CoV-2 were highly attenuated in both cell culture and mice, indicating that this isoleucine residue acts as a gate that controls ADP-ribose binding for efficient virus replication. These results highlight the function of this highly conserved residue and provide unique insight into how macrodomains control ADP-ribose binding and hydrolysis to promote viral replication.

Spatial examination of social and environmental drivers of Middle East respiratory syndrome coronavirus (MERS-CoV) across Kenya.

Climate and agricultural land-use change has increased the likelihood of infectious disease emergence and transmissions, but these drivers are often examined separately as combined effects are ignored. Further, seldom are the influence of climate and agricultural land use on emerging infectious diseases examined in a spatially explicit way at regional scales. Our objective in this study was to spatially examine the climate, agriculture, and socio-demographic factors related to agro-pastoralism, and especially the combined effects of these variables that can influence the prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels across northern Kenya. Our research questions focused on: (1) How MERS-CoV in dromedary camels has varied across geographic regions of northern Kenya, and (2) what climate, agriculture, and socio-demographic factors of agro-pastoralism were spatially related to the geographic variation of MERS-CoV cases in dromedary camels. To answer our questions, we analyzed the spatial distribution of historical cases based on serological evidence of MERS-CoV at the county level and applied spatial statistical analysis to examine the spatial relationships of the MERS-CoV cases between 2016 and 2018 to climate, agriculture, and socio-demographic factors of agro-pastoralism. Regional differences in MERS-CoV cases were spatially correlated with both social and environmental factors, and particularly ethno-religious camel practices, which highlight the complexity in the distribution of MERS-CoV in dromedary camels across Kenya.

Study of key residues in MERS-CoV and SARS-CoV-2 main proteases for resistance against clinically applied inhibitors nirmatrelvir and ensitrelvir

The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an epidemic, zoonotically emerging pathogen initially reported in Saudi Arabia in 2012. MERS-CoV has the potential to mutate or recombine with other coronaviruses, thus acquiring the ability to efficiently spread among humans and become pandemic. Its high mortality rate of up to 35% and the absence of effective targeted therapies call for the development of antiviral drugs for this pathogen. Since the beginning of the SARS-CoV-2 pandemic, extensive research has focused on identifying protease inhibitors for the treatment of SARS-CoV-2. Our intention was therefore to assess whether these protease inhibitors are viable options for combating MERS-CoV. To that end, we used previously established protease assays to quantify inhibition of SARS-CoV-2, MERS-CoV and other main proteases. Nirmatrelvir inhibited several of these proteases, whereas ensitrelvir was less broadly active. To simulate nirmatrelvir’s clinical use against MERS-CoV and subsequent resistance development, we applied a safe, surrogate virus-based system. Using the surrogate virus, we previously selected hallmark mutations of SARS-CoV-2-Mpro, such as T21I, M49L, S144A, E166A/K/V and L167F. In the current study, we selected a pool of MERS-CoV-Mpro mutants, characterized the resistance and modelled the steric effect of catalytic site mutants S142G, S142R, S147Y and A171S.

Novel triplex nucleic acid lateral flow immunoassay for rapid detection of Nipah virus, Middle East respiratory syndrome coronavirus and Reston ebolavirus

We report the development of a triplex nucleic acid lateral flow immunoassay (NALFIA) for the detection of the genomes of Nipah virus (NiV), Middle East respiratory syndrome coronavirus (MERS-CoV) and Reston ebolavirus (REBOV), which are intended for screening bats as well as other hosts and reservoirs of these three viruses. Our triplex NALFIA is a two-step assay format: the target nucleic acid in the sample is first amplified using tagged primers, and the tagged dsDNA amplicons are captured by antibodies immobilized on the NALFIA device, resulting in signal development from the binding of a streptavidin-colloidal gold conjugate to a biotin tag on the captured amplicons. Triplex amplification of the N gene of NiV, the UpE gene of MERS-CoV, and the Vp40 gene of REBOV was optimized, and three compatible combinations of hapten labels and antibodies were identified for end point detection. The lowest RNA copy numbers detected by the triplex NALFIA were 8.21e4 for the NiV N target, 7.09e1 for the MERS-CoV UpE target, and 1.83e4 for the REBOV Vp40 target. Using simulated samples, the sensitivity and specificity for MERS-CoV and REBOV targets were estimated to be 100%, while the sensitivity and specificity for the NiV target were 91% and 93.3%, respectively. The compliance rate between triplex NALFIA and real-time RT‒PCR was 92% for the NiV N target and 100% for the MERS-CoV UpE and REBOV Vp40 targets.

Human coronavirus OC43 nanobody neutralizes virus and protects mice from infection.

The pandemic potential presented by coronaviruses has been demonstrated by the ongoing COVID-19 pandemic and previous epidemics caused by severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus. Outside of these major pathogenic coronaviruses, there are four endemic coronaviruses that infect humans: hCoV-OC43, hCoV-229E, hCoV-HKU1, and hCoV-NL63. We identified a collection of nanobodies against human coronavirus OC43 (hCoV-OC43) and found that two high-affinity nanobodies potently neutralized hCoV-OC43 at low nanomolar concentrations. Prophylactic administration of one neutralizing nanobody reduced viral loads in mice infected with hCoV-OC43, showing the potential for nanobody-based therapies for hCoV-OC43 infections.

Traditional Chinese Medicine as the Preventive and Therapeutic Remedy for COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic still has tremendous impacts on the global socio-economy and quality of living. The traditional Chinese Medicines (TCM) approach showed encouraging results during previous outbreaks of Severe Acute Respiratory Syndrome-related Coronavirus (SARS-CoV) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV). With limited treatment availability, TCM herbs and formulations could be useful to reduce COVID-19 symptoms and potential sources for discovering novel therapeutic targets. We reviewed 12 TCM herbs and formulations recommended for COVID-19 management by the National Health Commission and as National Administration of Traditional Chinese Medicine of the People's Republic of China. This article explored the Chinese national authorities' guidelines from 2003 to 2020, the scientific data in public databases for the recommended TCM remedies, and their potential mechanistic actions in COVID-19 management. Several TCM herbs and formulations could potentially benefit COVID-19 management. The recommended TCM oral preparations list includes Huoxiang zhengqi, Jinhua Qinggan, Lianhua Qingwen, and Shufeng jiedu; the recommended injection preparations comprise Xiyanping Xuebijing, Re-Du-Ning, Tanreqing, Xingnaojing, Shenfu, Shengmai, and Shenmai. TCM remedies are viable options for symptom alleviation and management of COVID-19. The current SARS-CoV-2 pandemic presents an opportunity to find novel therapeutic targets from TCM-active ingredients. Despite the recommendations in Chinese National guidelines, these remedies warrant further assessments in well-designed clinical trials to ascertain their efficacy in the treatment of COVID-19.

Circulation of Non-Middle East Respiratory Syndrome (MERS) Coronaviruses in Imported Camels in Saudi Arabia.

Background Coronaviruses (CoVs) pose significant health risks to humans, with recent outbreaks like severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscoring their zoonotic potential. Dromedary camels (Camelus dromedarius) have been implicated as intermediate hosts for MERS-CoV, prompting heightened surveillance efforts. This study aims to identify non-MERS-CoV CoVs in imported camels at the Jeddah seaport, Saudi Arabia, using molecular techniques. Methods Camel nasal swabs (n = 337) were collected from imported dromedary camels arriving at the Jeddah Islamic seaport from Sudan and Djibouti. Samples were tested for CoVs using real-time real-time reverse transcription polymerase chain reaction (RT-PCR) targeting the RNA-dependent RNA polymerase gene. Positive samples were confirmed by conventional RT-PCR and Sanger sequencing. Selected samples underwent RNA sequencing to identify viral genomes. The study underscores the importance of molecular surveillance in camels to mitigate zoonotic risks. Results Out of 337 camel samples tested, 28 (8.30%) were positive for CoVs, predominantly from camels imported from Djibouti, compared to Sudan (13.39% vs. 5.78%). Sequence analysis confirmed the presence of non-MERS CoVs, including camel alpha-coronavirus and human CoV-229E-related strains. These findings highlight potential viral diversity and transmission risks in imported camel populations. Conclusion This study identifies diverse CoVs circulating in imported dromedary camels at the Jeddah Islamic seaport, Saudi Arabia, underscoring their potential role in zoonotic transmission. Enhanced surveillance and collaborative efforts are essential to mitigate public health risks associated with novel coronavirus strains from camel populations.

TO DETECT AND CLASSIFY COPD LIKE MERS-COV AND PNEUMONIA USING MACHINE LEARNING

Chronic Obstructive Pulmonary Disease (COPD) is a global public health concern, encompassing a spectrum of respiratory conditions, including Pneumonia and Middle East Respiratory Syndrome Coronavirus (MERS-CoV). Early and accurate detection of COPD-related diseases is crucial for effective patient management and improved outcomes. This research presents a novel approach to detect and classify COPD diseases, specifically Pneumonia and MERS-CoV, by leveraging advanced machine learning techniques. We investigate the application of machine learning for the early detection and classification of Chronic Obstructive Pulmonary Disease (COPD)-related diseases, including pneumonia and MERS-CoV. A multifaceted dataset encompassing medical images, clinical data, and patient histories is leveraged to train and validate machine learning models. Convolutional Neural Networks (CNNs) are employed for image analysis, while traditional machine learning algorithms handle clinical data. Feature engineering techniques are used to optimize data informativeness. This approach holds promise for improving diagnostic accuracy, enabling timely interventions, and ultimately contributing to better outcomes in COPD management. Keywords: Convolutional neural networks , Machine learning, Training Data , Transfer Learning

IL-37 possesses both anti-inflammatory and antiviral effects against Middle East respiratory syndrome coronavirus infection.

The aim was to elucidate the function of IL-37 in middle east respiratory syndrome coronavirus (MERS-CoV) infection, thereby providing a novel therapeutic strategy for managing the clinical treatment of inflammatory response caused by respiratory virus infection. We investigated the development of MERS by infecting hDPP4 mice with hCoV-EMC (107 TCID50 [50% tissue culture infectious dose]) intranasally. We infected A549 cells with MERS-CoV, which concurrently interfered with IL-37, detecting the viral titer, viral load, and cytokine expression at certain points postinfection. Meanwhile, we administered IL-37 (12.5 μg/kg) intravenously to hDPP4 mice 2 h after MERS-CoV-2 infection and collected the serum and lungs 5 days after infection to investigate the efficacy of IL-37 in MERS-CoV infection. The viral titer of MERS-CoV-infected A549 cells interfering with IL-37 was significantly reduced by 4.7-fold, and the viral load of MERS-CoV-infected hDPP4 mice was decreased by 59-fold in lung tissue. Furthermore, the administration of IL-37 suppressed inflammatory cytokine and chemokine (monocyte chemoattractant protein 1, interferon-γ, and IL-17A) expression and ameliorated the infiltration of inflammatory cells in hDPP4 mice. IL-37 exhibits protective properties in severe pneumonia induced by MERS-CoV infection. This effect is achieved through attenuation of lung viral load, suppression of inflammatory cytokine secretion, reduction in inflammatory cell infiltration, and mitigation of pulmonary injury.

The oral nucleoside prodrug GS-5245 is efficacious against SARS-CoV-2 and other endemic, epidemic, and enzootic coronaviruses.

Despite the wide availability of several safe and effective vaccines that prevent severe COVID-19, the persistent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that can evade vaccine-elicited immunity remains a global health concern. In addition, the emergence of SARS-CoV-2 VOCs that can evade therapeutic monoclonal antibodies underscores the need for additional, variant-resistant treatment strategies. Here, we characterize the antiviral activity of GS-5245, obeldesivir (ODV), an oral prodrug of the parent nucleoside GS-441524, which targets the highly conserved viral RNA-dependent RNA polymerase (RdRp). We show that GS-5245 is broadly potent in vitro against alphacoronavirus HCoV-NL63, SARS-CoV, SARS-CoV-related bat-CoV RsSHC014, Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV-2 WA/1, and the highly transmissible SARS-CoV-2 BA.1 Omicron variant. Moreover, in mouse models of SARS-CoV, SARS-CoV-2 (WA/1 and Omicron B1.1.529), MERS-CoV, and bat-CoV RsSHC014 pathogenesis, we observed a dose-dependent reduction in viral replication, body weight loss, acute lung injury, and pulmonary function with GS-5245 therapy. Last, we demonstrate that a combination of GS-5245 and main protease (Mpro) inhibitor nirmatrelvir improved outcomes in vivo against SARS-CoV-2 compared with the single agents. Together, our data support the clinical evaluation of GS-5245 against coronaviruses that cause or have the potential to cause human disease.

Characterization and immunogenicity assessment of MERS-CoV pre-fusion spike trimeric oligomers as vaccine immunogen

ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) is a lethal beta-coronavirus that emerged in 2012. The virus is part of the WHO blueprint priority list with a concerning fatality rate of 35%. Scientific efforts are ongoing for the development of vaccines, anti-viral and biotherapeutics, which are majorly directed toward the structural spike protein. However, the ongoing effort is challenging due to conformational instability of the spike protein and the evasion strategy posed by the MERS-CoV. In this study, we have expressed and purified the MERS-CoV pre-fusion spike protein in the Expi293F mammalian expression system. The purified protein was extensively characterized for its biochemical and biophysical properties. Thermal stability analysis showed a melting temperature of 58°C and the protein resisted major structural changes at elevated temperature as revealed by fluorescence spectroscopy and circular dichroism. Immunological assessment of the MERS-CoV spike immunogen in BALB/c mice with AddaVaxTM and Imject alum adjuvants showed elicitation of high titer antibody responses but a more balanced Th1/Th2 response with AddaVaxTM squalene like adjuvant. Together, our results suggest the formation of higher-order trimeric pre-fusion MERS-CoV spike proteins, which were able to induce robust immune responses. The comprehensive characterization of MERS-CoV spike protein warrants a better understanding of MERS spike protein and future vaccine development efforts.

Predicting drug-Protein interaction with deep learning framework for molecular graphs and sequences: Potential candidates against SAR-CoV-2.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the COVID-19 disease, which represents a new life-threatening disaster. Regarding viral infection, many therapeutics have been investigated to alleviate the epidemiology such as vaccines and receptor decoys. However, the continuous mutating coronavirus, especially the variants of Delta and Omicron, are tended to invalidate the therapeutic biological product. Thus, it is necessary to develop molecular entities as broad-spectrum antiviral drugs. Coronavirus replication is controlled by the viral 3-chymotrypsin-like cysteine protease (3CLpro) enzyme, which is required for the virus's life cycle. In the cases of severe acute respiratory syndrome coronavirus (SARS-CoV) and middle east respiratory syndrome coronavirus (MERS-CoV), 3CLpro has been shown to be a promising therapeutic development target. Here we proposed an attention-based deep learning framework for molecular graphs and sequences, training from the BindingDB 3CLpro dataset (114,555 compounds). After construction of such model, we conducted large-scale screening the in vivo/vitro dataset (276,003 compounds) from Zinc Database and visualize the candidate compounds with attention score. geometric-based affinity prediction was employed for validation. Finally, we established a 3CLpro-specific deep learning framework, namely GraphDPI-3CL (AUROC: 0.958) achieved superior performance beyond the existing state of the art model and discovered 10 molecules with a high binding affinity of 3CLpro and superior binding mode.

Quantitative assay to analyze neutralization and inhibition of authentic Middle East respiratory syndrome coronavirus

To date, there is no licensed vaccine for Middle East respiratory syndrome coronavirus (MERS-CoV). Therefore, MERS-CoV is one of the diseases targeted by the Coalition for Epidemic Preparedness Innovations (CEPI) vaccine development programs and has been classified as a priority disease by the World Health Organization (WHO). An important measure of vaccine immunogenicity and antibody functionality is the detection of virus-neutralizing antibodies. We have developed and optimized a microneutralization assay (MNA) using authentic MERS-CoV and standardized automatic counting of virus foci. Compared to our standard virus neutralization assay, the MNA showed improved sensitivity when analyzing 30 human sera with good correlation of results (Spearman’s correlation coefficient r = 0.8917, p value < 0.0001). It is important to use standardized materials, such as the WHO international standard (IS) for anti-MERS-CoV immunoglobulin G, to compare the results from clinical trials worldwide. Therefore, in addition to the neutralizing titers (NT50 = 1384, NT80 = 384), we determined the IC50 and IC80 of WHO IS in our MNA to be 0.67 IU/ml and 2.6 IU/ml, respectively. Overall, the established MNA is well suited to reliably quantify vaccine-induced neutralizing antibodies with high sensitivity.