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1.
J Virol ; 94(13)2020 06 16.
Article in English | MEDLINE | ID: covidwho-1583223

ABSTRACT

Fusion with, and subsequent entry into, the host cell is one of the critical steps in the life cycle of enveloped viruses. For Middle East respiratory syndrome coronavirus (MERS-CoV), the spike (S) protein is the main determinant of viral entry. Proteolytic cleavage of the S protein exposes its fusion peptide (FP), which initiates the process of membrane fusion. Previous studies on the related severe acute respiratory syndrome coronavirus (SARS-CoV) FP have shown that calcium ions (Ca2+) play an important role in fusogenic activity via a Ca2+ binding pocket with conserved glutamic acid (E) and aspartic acid (D) residues. SARS-CoV and MERS-CoV FPs share a high sequence homology, and here, we investigated whether Ca2+ is required for MERS-CoV fusion by screening a mutant array in which E and D residues in the MERS-CoV FP were substituted with neutrally charged alanines (A). Upon verifying mutant cell surface expression and proteolytic cleavage, we tested their ability to mediate pseudoparticle (PP) infection of host cells in modulating Ca2+ environments. Our results demonstrate that intracellular Ca2+ enhances MERS-CoV wild-type (WT) PP infection by approximately 2-fold and that E891 is a crucial residue for Ca2+ interaction. Subsequent electron spin resonance (ESR) experiments revealed that this enhancement could be attributed to Ca2+ increasing MERS-CoV FP fusion-relevant membrane ordering. Intriguingly, isothermal calorimetry showed an approximate 1:1 MERS-CoV FP to Ca2+ ratio, as opposed to an 1:2 SARS-CoV FP to Ca2+ ratio, suggesting significant differences in FP Ca2+ interactions of MERS-CoV and SARS-CoV FP despite their high sequence similarity.IMPORTANCE Middle East respiratory syndrome coronavirus (MERS-CoV) is a major emerging infectious disease with zoonotic potential and has reservoirs in dromedary camels and bats. 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. In order to develop novel drugs and vaccines, it is important to understand the molecular mechanisms that enable the virus to infect host cells. Our data have found that calcium is an important regulator of viral fusion by interacting with negatively charged residues in the MERS-CoV FP region. This information can guide therapeutic solutions to block this calcium interaction and also repurpose already approved drugs for this use for a fast response to MERS-CoV outbreaks.


Subject(s)
Calcium/metabolism , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Host-Pathogen Interactions , Ions/metabolism , Membrane Fusion , Middle East Respiratory Syndrome Coronavirus/physiology , Virus Internalization , Amino Acid Sequence , Amino Acid Substitution , Animals , Cell Line , Chlorocebus aethiops , Humans , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Models, Molecular , Mutation , Protein Binding , Proteolysis , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Structure-Activity Relationship , Vero Cells , Virulence , Virus Assembly
2.
Int J Mol Sci ; 22(20)2021 Oct 14.
Article in English | MEDLINE | ID: covidwho-1470888

ABSTRACT

The ongoing COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a globally leading public health concern over the past two years. Despite the development and administration of multiple vaccines, the mutation of newer strains and challenges to universal immunity has shifted the focus to the lack of efficacious drugs for therapeutic intervention for the disease. As with SARS-CoV, MERS-CoV, and other non-respiratory viruses, flavonoids present themselves as a promising therapeutic intervention given their success in silico, in vitro, in vivo, and more recently, in clinical studies. This review focuses on data from in vitro studies analyzing the effects of flavonoids on various key SARS-CoV-2 targets and presents an analysis of the structure-activity relationships for the same. From 27 primary papers, over 69 flavonoids were investigated for their activities against various SARS-CoV-2 targets, ranging from the promising 3C-like protease (3CLpro) to the less explored nucleocapsid (N) protein; the most promising were quercetin and myricetin derivatives, baicalein, baicalin, EGCG, and tannic acid. We further review promising in silico studies featuring activities of flavonoids against SARS-CoV-2 and list ongoing clinical studies involving the therapeutic potential of flavonoid-rich extracts in combination with synthetic drugs or other polyphenols and suggest prospects for the future of flavonoids against SARS-CoV-2.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Flavonoids/therapeutic use , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/virology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , Coronavirus Nucleocapsid Proteins/antagonists & inhibitors , Coronavirus Nucleocapsid Proteins/metabolism , Flavonoids/chemistry , Flavonoids/pharmacology , Humans , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/physiology , Phosphoproteins/antagonists & inhibitors , Phosphoproteins/metabolism , Rhinovirus/drug effects , Rhinovirus/physiology , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Virus Internalization/drug effects
3.
Nat Commun ; 12(1): 5536, 2021 09 20.
Article in English | MEDLINE | ID: covidwho-1428813

ABSTRACT

Coronaviruses (CoVs) are important human pathogens for which no specific treatment is available. Here, we provide evidence that pharmacological reprogramming of ER stress pathways can be exploited to suppress CoV replication. The ER stress inducer thapsigargin efficiently inhibits coronavirus (HCoV-229E, MERS-CoV, SARS-CoV-2) replication in different cell types including primary differentiated human bronchial epithelial cells, (partially) reverses the virus-induced translational shut-down, improves viability of infected cells and counteracts the CoV-mediated downregulation of IRE1α and the ER chaperone BiP. Proteome-wide analyses revealed specific pathways, protein networks and components that likely mediate the thapsigargin-induced antiviral state, including essential (HERPUD1) or novel (UBA6 and ZNF622) factors of ER quality control, and ER-associated protein degradation complexes. Additionally, thapsigargin blocks the CoV-induced selective autophagic flux involving p62/SQSTM1. The data show that thapsigargin hits several central mechanisms required for CoV replication, suggesting that this compound (or derivatives thereof) may be developed into broad-spectrum anti-CoV drugs.


Subject(s)
Endoplasmic Reticulum Stress , SARS-CoV-2/physiology , Virus Replication/physiology , Animals , Autophagy/drug effects , Bronchi/pathology , COVID-19/pathology , COVID-19/virology , Cell Differentiation/drug effects , Cell Extracts , Cell Line , Cell Survival/drug effects , Chlorocebus aethiops , Coronavirus 229E, Human/physiology , Down-Regulation/drug effects , Endoplasmic Reticulum Stress/drug effects , Endoplasmic Reticulum Stress/genetics , Endoplasmic Reticulum-Associated Degradation/drug effects , Epithelial Cells/drug effects , Epithelial Cells/virology , Heat-Shock Proteins/metabolism , Humans , Macrolides/pharmacology , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/physiology , Protein Biosynthesis/drug effects , Proteome/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reproducibility of Results , SARS-CoV-2/drug effects , Thapsigargin/pharmacology , Unfolded Protein Response/drug effects , Vero Cells , Virus Replication/drug effects
4.
Med Mal Infect ; 50(3): 243-251, 2020 May.
Article in English | MEDLINE | ID: covidwho-1409419

ABSTRACT

Since the first case of human infection by the Middle East respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia in June 2012, more than 2260 cases of confirmed MERS-CoV infection and 803 related deaths have been reported since the 16th of October 2018. The vast majority of these cases (71%) were reported in Saudi Arabia but the epidemic has now spread to 27 countries and has not ceased 6 years later, unlike SARS-CoV that disappeared a little less than 2 years after emerging. Due to the high fatality rate observed in MERS-CoV infected patients (36%), much effort has been put into understanding the origin and pathophysiology of this novel coronavirus to prevent it from becoming endemic in humans. This review focuses in particular on the origin, epidemiology and clinical manifestations of MERS-CoV, as well as the diagnosis and treatment of infected patients. The experience gained over recent years on how to manage the different risks related to this kind of epidemic will be key to being prepared for future outbreaks of communicable disease.


Subject(s)
Coronavirus Infections/virology , Middle East Respiratory Syndrome Coronavirus/physiology , Animals , Antiviral Agents/therapeutic use , Camelus/virology , Chiroptera/virology , Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Emerging/prevention & control , Communicable Diseases, Emerging/virology , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Coronavirus Infections/therapy , Disease Management , Disease Reservoirs , Epidemics , Extracorporeal Membrane Oxygenation , Genome, Viral , Global Health , Humans , Hygiene , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Risk Factors , Saudi Arabia/epidemiology , Survival Rate , Symptom Assessment , Travel , Viral Vaccines
5.
Microbes Infect ; 22(4-5): 226-229, 2020.
Article in English | MEDLINE | ID: covidwho-1386324

ABSTRACT

During virus infection, host toll-like receptors (TLRs) can recognize different pathogen-associated molecular patterns and trigger the innate immune response. TLR7/8 can identify the single-stranded RNA (ssRNA) of the virus. This study aimed to search ssRNA sequences recognized by TLR7/8 from the SARS-CoV-2, SARS-CoV, and MERS-CoV whole genomes by a bioinformatic technique. The immunoinformatic approach showed that the SARS-CoV-2 genome has more ssRNA fragments that could be recognized by TLR7/8 than the SARS-CoV genome. These findings suggest innate immune hyperactivation by SARS-CoV-2. This activity is possibly able to provoke a robust proinflammatory response via TLR7/8 recognition and cause acute lung injury.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/virology , Middle East Respiratory Syndrome Coronavirus/physiology , Pneumonia, Viral/virology , SARS Virus/physiology , Toll-Like Receptor 7/physiology , Toll-Like Receptor 8/physiology , COVID-19 , Computational Biology , Genome, Viral , Humans , Immunity, Innate , Pandemics , SARS-CoV-2 , Virus Attachment
6.
Cell ; 181(5): 969-977, 2020 05 28.
Article in English | MEDLINE | ID: covidwho-1385208

ABSTRACT

SARS-CoV-2 infection is mild in the majority of individuals but progresses into severe pneumonia in a small proportion of patients. The increased susceptibility to severe disease in the elderly and individuals with co-morbidities argues for an initial defect in anti-viral host defense mechanisms. Long-term boosting of innate immune responses, also termed "trained immunity," by certain live vaccines (BCG, oral polio vaccine, measles) induces heterologous protection against infections through epigenetic, transcriptional, and functional reprogramming of innate immune cells. We propose that induction of trained immunity by whole-microorganism vaccines may represent an important tool for reducing susceptibility to and severity of SARS-CoV-2.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/immunology , Immunity, Innate , Immunomodulation , Pneumonia, Viral/immunology , SARS Virus/physiology , Animals , BCG Vaccine/immunology , COVID-19 , Clinical Trials as Topic , Coronavirus Infections/pathology , Coronavirus Infections/physiopathology , Coronavirus Infections/transmission , Humans , Immunity, Innate/drug effects , Lung/immunology , Lung/pathology , Lymphopenia/pathology , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/physiopathology , Pneumonia, Viral/transmission , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/pathology , Virus Replication
7.
Viruses ; 13(8)2021 08 18.
Article in English | MEDLINE | ID: covidwho-1360825

ABSTRACT

Recent outbreaks of zoonotic coronaviruses, such as Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have caused tremendous casualties and great economic shock. Although some repurposed drugs have shown potential therapeutic efficacy in clinical trials, specific therapeutic agents targeting coronaviruses have not yet been developed. During coronavirus replication, a replicase gene cluster, including RNA-dependent RNA polymerase (RdRp), is alternatively translated via a process called -1 programmed ribosomal frameshift (-1 PRF) by an RNA pseudoknot structure encoded in viral RNAs. The coronavirus frameshifting has been identified previously as a target for antiviral therapy. In this study, the frameshifting efficiencies of MERS-CoV, SARS-CoV and SARS-CoV-2 were determined using an in vitro -1 PRF assay system. Our group has searched approximately 9689 small molecules to identify potential -1 PRF inhibitors. Herein, we found that a novel compound, 2-(5-acetylthiophen-2yl)furo[2,3-b]quinoline (KCB261770), inhibits the frameshifting of MERS-CoV and effectively suppresses viral propagation in MERS-CoV-infected cells. The inhibitory effects of 87 derivatives of furo[2,3-b]quinolines were also examined showing less prominent inhibitory effect when compared to compound KCB261770. We demonstrated that KCB261770 inhibits the frameshifting without suppressing cap-dependent translation. Furthermore, this compound was able to inhibit the frameshifting, to some extent, of SARS-CoV and SARS-CoV-2. Therefore, the novel compound 2-(5-acetylthiophen-2yl)furo[2,3-b]quinoline may serve as a promising drug candidate to interfere with pan-coronavirus frameshifting.


Subject(s)
Antiviral Agents/pharmacology , Frameshifting, Ribosomal/drug effects , Middle East Respiratory Syndrome Coronavirus/drug effects , Quinolines/pharmacology , SARS Virus/drug effects , SARS-CoV-2/drug effects , A549 Cells , Animals , Cell Line , Frameshifting, Ribosomal/physiology , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/physiology , SARS Virus/genetics , SARS Virus/physiology , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Small Molecule Libraries , Viral Zoonoses/virology , Virus Replication/drug effects
8.
Viruses ; 13(8)2021 08 10.
Article in English | MEDLINE | ID: covidwho-1348697

ABSTRACT

The novel coronavirus SARS-CoV-2 is the seventh identified human coronavirus. Understanding the extent of pre-existing immunity induced by seropositivity to endemic seasonal coronaviruses and the impact of cross-reactivity on COVID-19 disease progression remains a key research question in immunity to SARS-CoV-2 and the immunopathology of COVID-2019 disease. This paper describes a panel of lentiviral pseudotypes bearing the spike (S) proteins for each of the seven human coronaviruses (HCoVs), generated under similar conditions optimized for high titre production allowing a high-throughput investigation of antibody neutralization breadth. Optimal production conditions and most readily available permissive target cell lines were determined for spike-mediated entry by each HCoV pseudotype: SARS-CoV-1, SARS-CoV-2 and HCoV-NL63 best transduced HEK293T/17 cells transfected with ACE2 and TMPRSS2, HCoV-229E and MERS-CoV preferentially entered HUH7 cells, and CHO cells were most permissive for the seasonal betacoronavirus HCoV-HKU1. Entry of ACE2 using pseudotypes was enhanced by ACE2 and TMPRSS2 expression in target cells, whilst TMPRSS2 transfection rendered HEK293T/17 cells permissive for HCoV-HKU1 and HCoV-OC43 entry. Additionally, pseudotype viruses were produced bearing additional coronavirus surface proteins, including the SARS-CoV-2 Envelope (E) and Membrane (M) proteins and HCoV-OC43/HCoV-HKU1 Haemagglutinin-Esterase (HE) proteins. This panel of lentiviral pseudotypes provides a safe, rapidly quantifiable and high-throughput tool for serological comparison of pan-coronavirus neutralizing responses; this can be used to elucidate antibody dynamics against individual coronaviruses and the effects of antibody cross-reactivity on clinical outcome following natural infection or vaccination.


Subject(s)
Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/immunology , Coronavirus/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Viral/blood , Broadly Neutralizing Antibodies/blood , Cell Line , Coronavirus 229E, Human/immunology , Coronavirus 229E, Human/physiology , Coronavirus NL63, Human/immunology , Coronavirus NL63, Human/physiology , Coronavirus OC43, Human/immunology , Coronavirus OC43, Human/physiology , Cross Reactions , Humans , Lentivirus/genetics , Middle East Respiratory Syndrome Coronavirus/immunology , Middle East Respiratory Syndrome Coronavirus/physiology , Neutralization Tests , Plasmids , SARS-CoV-2/physiology , Transfection , Virus Internalization
9.
Virology ; 562: 142-148, 2021 10.
Article in English | MEDLINE | ID: covidwho-1331288

ABSTRACT

SARS-CoV, MERS-CoV, and potentially SARS-CoV-2 emerged as novel human coronaviruses following cross-species transmission from animal hosts. Although the receptor binding characteristics of human coronaviruses are well documented, the role of carbohydrate binding in addition to recognition of proteinaceous receptors has not been fully explored. Using natural glycan microarray technology, we identified N-glycans in the human lung that are recognized by various human and animal coronaviruses. All viruses tested, including SARS-CoV-2, bound strongly to a range of phosphorylated, high mannose N-glycans and to a very specific set of sialylated structures. Examination of two linked strains, human CoV OC43 and bovine CoV Mebus, reveals shared binding to the sialic acid form Neu5Gc (not found in humans), supporting the evidence for cross-species transmission of the bovine strain. Our findings, revealing robust recognition of lung glycans, suggest that these receptors could play a role in the initial stages of coronavirus attachment and entry.


Subject(s)
COVID-19/virology , Host Microbial Interactions/physiology , Middle East Respiratory Syndrome Coronavirus/metabolism , Polysaccharides/metabolism , SARS-CoV-2/metabolism , Animals , Cattle , Humans , Lung/metabolism , Mannose/chemistry , Middle East Respiratory Syndrome Coronavirus/physiology , N-Acetylneuraminic Acid/chemistry , Phosphorylation , Protein Array Analysis , Protein Binding , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/physiology
10.
Am J Chin Med ; 48(7): 1539-1552, 2020.
Article in English | MEDLINE | ID: covidwho-1327716

ABSTRACT

The SARS-CoV-2 outbreak in 2019 highlighted the fact that no specific medications providing effective treatment have been identified and approved. We explored the possibilities for COVID-19 by systematically reviewing evidence on the efficacy and safety of glycyrrhizin preparations for SARS and MERS. Electronic databases were systematically searched from inception to February 2020 for eligible studies that evaluated the efficacy and safety of glycyrrhizin preparations for SARS and MERS. A quantitative analysis or descriptive analysis was applied. Five retrospective cohort studies were included, and NOS scores ranged from 5-7 points. The clinical symptoms of dry cough, chest distress and dyspnoea improved quickly, and elevated serum levels of aminotransferase decreased after compound glycyrrhizin treatment. The SARS-CoV antibody appeared earlier in the treated group than in the control group ([Formula: see text][Formula: see text]d). Compared to that with conventional medications, the average period from peak to 50% improvement of lesions, in terms of X-ray manifestations, was shorter with compound glycyrrhizin treatment ([Formula: see text]2.1[Formula: see text]d), and treatment reduced the dosage ([Formula: see text][Formula: see text]mg/d) and duration of the corticosteroids used, without other serious adverse reactions. Based on the available evidence regarding glycyrrhizin preparations for treating SARS and MERS, we infer that compound glycyrrhizin could be an optional therapeutic strategy for SARS-CoV-2 infections, especially those complicated with liver damage. Further research using well-designed randomized clinical trials (RCTs) is warranted to determine the dosage and duration of use of compound glycyrrhizin and to monitor its specific adverse effects.


Subject(s)
COVID-19/drug therapy , Coronavirus Infections/drug therapy , Glycyrrhizic Acid/therapeutic use , Middle East Respiratory Syndrome Coronavirus/drug effects , SARS Virus/drug effects , SARS-CoV-2/drug effects , Severe Acute Respiratory Syndrome/drug therapy , Anti-Inflammatory Agents/therapeutic use , COVID-19/epidemiology , COVID-19/virology , Coronavirus Infections/virology , Humans , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , SARS Virus/physiology , SARS-CoV-2/physiology , Severe Acute Respiratory Syndrome/virology , Treatment Outcome
11.
Viruses ; 13(8)2021 07 27.
Article in English | MEDLINE | ID: covidwho-1325793

ABSTRACT

Over the past 18 years, three highly pathogenic human (h) coronaviruses (CoVs) have caused severe outbreaks, the most recent causative agent, SARS-CoV-2, being the first to cause a pandemic. Although much progress has been made since the COVID-19 pandemic started, much about SARS-CoV-2 and its disease, COVID-19, is still poorly understood. The highly pathogenic hCoVs differ in some respects, but also share some similarities in clinical presentation, the risk factors associated with severe disease, and the characteristic immunopathology associated with the progression to severe disease. This review aims to highlight these overlapping aspects of the highly pathogenic hCoVs-SARS-CoV, MERS-CoV, and SARS-CoV-2-briefly discussing the importance of an appropriately regulated immune response; how the immune response to these highly pathogenic hCoVs might be dysregulated through interferon (IFN) inhibition, antibody-dependent enhancement (ADE), and long non-coding RNA (lncRNA); and how these could link to the ensuing cytokine storm. The treatment approaches to highly pathogenic hCoV infections are discussed and it is suggested that a greater focus be placed on T-cell vaccines that elicit a cell-mediated immune response, using rapamycin as a potential agent to improve vaccine responses in the elderly and obese, and the potential of stapled peptides as antiviral agents.


Subject(s)
COVID-19/immunology , Coronavirus Infections/immunology , Severe Acute Respiratory Syndrome/immunology , Animals , COVID-19/epidemiology , COVID-19/virology , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Cytokines/immunology , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , SARS Virus/genetics , SARS Virus/physiology , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Severe Acute Respiratory Syndrome/epidemiology , Severe Acute Respiratory Syndrome/virology
12.
Front Immunol ; 12: 653110, 2021.
Article in English | MEDLINE | ID: covidwho-1305643

ABSTRACT

To characterize transcriptomic changes in endothelial cells (ECs) infected by coronaviruses, and stimulated by DAMPs, the expressions of 1311 innate immune regulatomic genes (IGs) were examined in 28 EC microarray datasets with 7 monocyte datasets as controls. We made the following findings: The majority of IGs are upregulated in the first 12 hours post-infection (PI), and maintained until 48 hours PI in human microvascular EC infected by middle east respiratory syndrome-coronavirus (MERS-CoV) (an EC model for COVID-19). The expressions of IGs are modulated in 21 human EC transcriptomic datasets by various PAMPs/DAMPs, including LPS, LPC, shear stress, hyperlipidemia and oxLDL. Upregulation of many IGs such as nucleic acid sensors are shared between ECs infected by MERS-CoV and those stimulated by PAMPs and DAMPs. Human heart EC and mouse aortic EC express all four types of coronavirus receptors such as ANPEP, CEACAM1, ACE2, DPP4 and virus entry facilitator TMPRSS2 (heart EC); most of coronavirus replication-transcription protein complexes are expressed in HMEC, which contribute to viremia, thromboembolism, and cardiovascular comorbidities of COVID-19. ECs have novel trained immunity (TI), in which subsequent inflammation is enhanced. Upregulated proinflammatory cytokines such as TNFα, IL6, CSF1 and CSF3 and TI marker IL-32 as well as TI metabolic enzymes and epigenetic enzymes indicate TI function in HMEC infected by MERS-CoV, which may drive cytokine storms. Upregulated CSF1 and CSF3 demonstrate a novel function of ECs in promoting myelopoiesis. Mechanistically, the ER stress and ROS, together with decreased mitochondrial OXPHOS complexes, facilitate a proinflammatory response and TI. Additionally, an increase of the regulators of mitotic catastrophe cell death, apoptosis, ferroptosis, inflammasomes-driven pyroptosis in ECs infected with MERS-CoV and the upregulation of pro-thrombogenic factors increase thromboembolism potential. Finally, NRF2-suppressed ROS regulate innate immune responses, TI, thrombosis, EC inflammation and death. These transcriptomic results provide novel insights on the roles of ECs in coronavirus infections such as COVID-19, cardiovascular diseases (CVD), inflammation, transplantation, autoimmune disease and cancers.


Subject(s)
Coronavirus Infections/immunology , Cytokine Release Syndrome/immunology , Endothelial Cells/physiology , Inflammation/immunology , Middle East Respiratory Syndrome Coronavirus/physiology , NF-E2-Related Factor 2/metabolism , SARS-CoV-2/physiology , Alarmins/immunology , Animals , Datasets as Topic , Endothelial Cells/virology , Gene Expression Profiling , Humans , Immunity, Innate , Immunization , Mice , Myelopoiesis , Oxidative Stress , Thromboembolism
13.
J Clin Immunol ; 41(7): 1607-1620, 2021 10.
Article in English | MEDLINE | ID: covidwho-1298388

ABSTRACT

The complement system, a network of highly-regulated proteins, represents a vital part of the innate immune response. Over-activation of the complement system plays an important role in inflammation, tissue damage, and infectious disease severity. The prevalence of MERS-CoV in Saudi Arabia remains significant and cases are still being reported. The role of complement in Middle East Respiratory Syndrome coronavirus (MERS-CoV) pathogenesis and complement-modulating treatment strategies has received limited attention, and studies involving MERS-CoV-infected patients have not been reported. This study offers the first insight into the pulmonary expression profile including seven complement proteins, complement regulatory factors, IL-8, and RANTES in MERS-CoV infected patients without underlying chronic medical conditions. Our results significantly indicate high expression levels of complement anaphylatoxins (C3a and C5a), IL-8, and RANTES in the lungs of MERS-CoV-infected patients. The upregulation of lung complement anaphylatoxins, C5a, and C3a was positively correlated with IL-8, RANTES, and the fatality rate. Our results also showed upregulation of the positive regulatory complement factor P, suggesting positive regulation of the complement during MERS-CoV infection. High levels of lung C5a, C3a, factor P, IL-8, and RANTES may contribute to the immunopathology, disease severity, ARDS development, and a higher fatality rate in MERS-CoV-infected patients. These findings highlight the potential prognostic utility of C5a, C3a, IL-8, and RANTES as biomarkers for MERS-CoV disease severity and mortality. To further explore the prediction of functional partners (proteins) of highly expressed proteins (C5a, C3a, factor P, IL-8, and RANTES), the computational protein-protein interaction (PPI) network was constructed, and six proteins (hub nodes) were identified.


Subject(s)
Chemokine CCL5/genetics , Chemokine CCL5/metabolism , Complement C3a/metabolism , Complement C5a/metabolism , Coronavirus Infections/diagnosis , Interleukin-8/metabolism , Lung/metabolism , Middle East Respiratory Syndrome Coronavirus/physiology , Aged , Biomarkers/metabolism , Complement C3a/genetics , Complement C5a/genetics , Coronavirus Infections/metabolism , Coronavirus Infections/mortality , Female , Humans , Interleukin-8/genetics , Male , Middle Aged , Prognosis , Severity of Illness Index , Survival Analysis , Up-Regulation
14.
Methods Mol Biol ; 2099: 9-20, 2020.
Article in English | MEDLINE | ID: covidwho-1292544

ABSTRACT

Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging zoonotic pathogen with a broad host range. The extent of MERS-CoV in nature can be traced to its adaptable cell entry steps. The virus can bind host-cell carbohydrates as well as proteinaceous receptors. Following receptor interaction, the virus can utilize diverse host proteases for cleavage activation of virus-host cell membrane fusion and subsequent genome delivery. The fusion and genome delivery steps can be completed at variable times and places, either at or near cell surfaces or deep within endosomes. Investigators focusing on the CoVs have developed several methodologies that effectively distinguish these different cell entry pathways. Here we describe these methods, highlighting virus-cell entry factors, entry inhibitors, and viral determinants that specify the cell entry routes. While the specific methods described herein were utilized to reveal MERS-CoV entry pathways, they are equally suited for other CoVs, as well as other protease-dependent viral species.


Subject(s)
Coronavirus Infections/virology , Genome, Viral/genetics , Middle East Respiratory Syndrome Coronavirus/physiology , Virus Internalization , Cell Membrane/virology , Endosomes/virology , HEK293 Cells , Humans , Membrane Proteins/metabolism , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/isolation & purification , Peptide Hydrolases/metabolism , RNA-Binding Proteins/metabolism , Receptors, Virus/genetics , Receptors, Virus/metabolism , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
15.
Methods Mol Biol ; 2099: 137-159, 2020.
Article in English | MEDLINE | ID: covidwho-1292550

ABSTRACT

Since 2012, monthly cases of Middle East respiratory syndrome coronavirus (MERS-CoV) continue to cause severe respiratory disease that is fatal in ~35% of diagnosed individuals. The ongoing threat to global public health and the need for novel therapeutic countermeasures have driven the development of animal models that can reproducibly replicate the pathology associated with MERS-CoV in human infections. The inability of MERS-CoV to replicate in the respiratory tracts of mice, hamsters, and ferrets stymied initial attempts to generate small animal models. Identification of human dipeptidyl peptidase IV (hDPP4) as the receptor for MERS-CoV infection opened the door for genetic engineering of mice. Precise molecular engineering of mouse DPP4 (mDPP4) with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology maintained inherent expression profiles, and limited MERS-CoV susceptibility to tissues that naturally express mDPP4, notably the lower respiratory tract wherein MERS-CoV elicits severe pulmonary pathology. Here, we describe the generation of the 288-330+/+ MERS-CoV mouse model in which mice were made susceptible to MERS-CoV by modifying two amino acids on mDPP4 (A288 and T330), and the use of adaptive evolution to generate novel MERS-CoV isolates that cause fatal respiratory disease. The 288-330+/+ mice are currently being used to evaluate novel drug, antibody, and vaccine therapeutic countermeasures for MERS-CoV. The chapter starts with a historical perspective on the emergence of MERS-CoV and animal models evaluated for MERS-CoV pathogenesis, and then outlines the development of the 288-330+/+ mouse model, assays for assessing a MERS-CoV pulmonary infection in a mouse model, and describes some of the challenges associated with using genetically engineered mice.


Subject(s)
Coronavirus Infections/virology , Dipeptidyl Peptidase 4/genetics , Disease Models, Animal , Mice/genetics , Middle East Respiratory Syndrome Coronavirus/physiology , Respiratory Distress Syndrome/virology , Animals , CRISPR-Cas Systems , Coronavirus Infections/pathology , Dipeptidyl Peptidase 4/metabolism , Disease Susceptibility , Female , Genetic Engineering , Humans , Lung/virology , Male , Mice, Inbred C57BL , Respiratory Distress Syndrome/pathology
16.
Methods Mol Biol ; 2099: 3-8, 2020.
Article in English | MEDLINE | ID: covidwho-1292543

ABSTRACT

Forced viral adaptation is a powerful technique employed to study the ways viruses may overcome various selective pressures that reduce viral replication. Here, we describe methods for in vitro serial passaging of Middle East respiratory syndrome coronavirus (MERS-CoV) to select for mutations which increase replication on semi-permissive cell lines as described in Letko et al., Cell Rep 24, 1730-1737, 2018.


Subject(s)
Adaptation, Physiological/genetics , Coronavirus Infections/virology , Middle East Respiratory Syndrome Coronavirus/genetics , Virus Replication/genetics , Animals , Biological Evolution , Cell Line , Chlorocebus aethiops , Host Specificity , Humans , Middle East Respiratory Syndrome Coronavirus/physiology , Serial Passage , Vero Cells
17.
Cells ; 10(7)2021 06 28.
Article in English | MEDLINE | ID: covidwho-1288809

ABSTRACT

Betacoronaviruses, responsible for the "Severe Acute Respiratory Syndrome" (SARS) and the "Middle East Respiratory Syndrome" (MERS), use the spikes protruding from the virion envelope to attach and subsequently infect the host cells. The coronavirus spike (S) proteins contain receptor binding domains (RBD), allowing the specific recognition of either the dipeptidyl peptidase CD23 (MERS-CoV) or the angiotensin-converting enzyme ACE2 (SARS-Cov, SARS-CoV-2) host cell receptors. The heavily glycosylated S protein includes both complex and high-mannose type N-glycans that are well exposed at the surface of the spikes. A detailed analysis of the carbohydrate-binding specificity of mannose-binding lectins from plants, algae, fungi, and bacteria, revealed that, depending on their origin, they preferentially recognize either complex type N-glycans, or high-mannose type N-glycans. Since both complex and high-mannose glycans substantially decorate the S proteins, mannose-specific lectins are potentially useful glycan probes for targeting the SARS-CoV, MERS-CoV, and SARS-CoV-2 virions. Mannose-binding legume lectins, like pea lectin, and monocot mannose-binding lectins, like snowdrop lectin or the algal lectin griffithsin, which specifically recognize complex N-glycans and high-mannose glycans, respectively, are particularly adapted for targeting coronaviruses. The biomedical prospects of targeting coronaviruses with mannose-specific lectins are wide-ranging including detection, immobilization, prevention, and control of coronavirus infection.


Subject(s)
Lectins/pharmacology , Middle East Respiratory Syndrome Coronavirus/metabolism , SARS Virus/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , COVID-19/drug therapy , COVID-19/virology , Cyanobacteria/chemistry , Drug Delivery Systems/methods , Fungi/chemistry , Humans , Lectins/isolation & purification , Lectins/therapeutic use , Middle East Respiratory Syndrome Coronavirus/physiology , Plants/chemistry , Protein Binding , SARS Virus/physiology , SARS-CoV-2/physiology , Species Specificity , Virus Internalization/drug effects
18.
Int J Infect Dis ; 106: 43-51, 2021 May.
Article in English | MEDLINE | ID: covidwho-1279598

ABSTRACT

OBJECTIVE: To describe the clinical characteristics and outcomes of hospitalized coronavirus disease 2019 (COVID-19) patients in a middle east respiratory syndrome coronavirus (MERS-CoV) referral hospital during the peak months of the pandemic. DESIGN: A single-center case series of hospitalized individuals with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in King Saud University Medical City (KSUMC), an academic tertiary care hospital in Riyadh, Saudi Arabia. Clinical and biochemical markers were documented. Risks for ventilatory support, intensive care unit (ICU) admission and death are presented. RESULTS: Out of 12,688 individuals tested for SARS-CoV-2 by real time reverse transcriptase polymerase reaction (RT-PCR) from June 1 to August 31, 2020, 2,683 (21%) were positive for COVID-19. Of the latter, 605 (22%) patients required hospitalization with a median age of 55, 368 (61%) were male. The most common comorbidities were hypertension (43%) and diabetes (42%). Most patients presented with fever (66%), dyspnea (65%), cough (61%), elevated IL-6 (93.5%), D-dimer (90.1%), CRP (86.1%), and lymphopenia (41.7%). No MERS-CoV co-infection was detected. Overall, 91 patients (15%) died; risk factors associated with mortality were an age of 65 years or older OR 2.29 [95%CI 1.43-3.67], presence of two or more comorbidities OR 3.17 [95%CI 2.00-5.02], symptoms duration of seven days or less OR 3.189 [95%CI (1.64 - 6.19]) lymphopenia OR 3.388 [95%CI 2.10-5.44], high CRP OR 2.85 [95%CI 1.1-7.32], high AST OR 2.95 [95%CI 1.77-4.90], high creatinine OR 3.71 [95%CI 2.30-5.99], and high troponin-I OR 2.84 [95%CI 1.33-6.05]. CONCLUSION: There is a significant increase in severe cases of COVID-19. Mortality was associated with older age, shorter symptom duration, high CRP, low lymphocyte count, and end-organ damage.


Subject(s)
COVID-19/epidemiology , COVID-19/therapy , Hospitalization , Middle East Respiratory Syndrome Coronavirus/physiology , Pandemics , Referral and Consultation , Adult , Aged , Comorbidity , Female , Humans , Intensive Care Units , Male , Middle Aged , Risk Factors
19.
PLoS Pathog ; 17(5): e1009229, 2021 05.
Article in English | MEDLINE | ID: covidwho-1239922

ABSTRACT

While MERS-CoV (Middle East respiratory syndrome Coronavirus) provokes a lethal disease in humans, camelids, the main virus reservoir, are asymptomatic carriers, suggesting a crucial role for innate immune responses in controlling the infection. Experimentally infected camelids clear infectious virus within one week and mount an effective adaptive immune response. Here, transcription of immune response genes was monitored in the respiratory tract of MERS-CoV infected alpacas. Concomitant to the peak of infection, occurring at 2 days post inoculation (dpi), type I and III interferons (IFNs) were maximally transcribed only in the nasal mucosa of alpacas, while interferon stimulated genes (ISGs) were induced along the whole respiratory tract. Simultaneous to mild focal infiltration of leukocytes in nasal mucosa and submucosa, upregulation of the anti-inflammatory cytokine IL10 and dampened transcription of pro-inflammatory genes under NF-κB control were observed. In the lung, early (1 dpi) transcription of chemokines (CCL2 and CCL3) correlated with a transient accumulation of mainly mononuclear leukocytes. A tight regulation of IFNs in lungs with expression of ISGs and controlled inflammatory responses, might contribute to virus clearance without causing tissue damage. Thus, the nasal mucosa, the main target of MERS-CoV in camelids, seems central in driving an efficient innate immune response based on triggering ISGs as well as the dual anti-inflammatory effects of type III IFNs and IL10.


Subject(s)
Camelids, New World , Coronavirus Infections/immunology , Interferon Type I/metabolism , Interferons/metabolism , Middle East Respiratory Syndrome Coronavirus/immunology , Animals , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Camelids, New World/immunology , Camelids, New World/metabolism , Camelids, New World/virology , Chlorocebus aethiops , Coronavirus Infections/metabolism , Coronavirus Infections/prevention & control , Coronavirus Infections/veterinary , Disease Reservoirs/veterinary , Disease Resistance/drug effects , Disease Resistance/genetics , Disease Resistance/immunology , Gene Expression Regulation , Immunity, Innate/physiology , Inflammation/immunology , Inflammation/metabolism , Inflammation/veterinary , Inflammation/virology , Interferon Type I/genetics , Interferon Type I/pharmacology , Interferons/genetics , Interferons/pharmacology , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/physiology , Nasal Mucosa/drug effects , Nasal Mucosa/immunology , Nasal Mucosa/metabolism , Nasal Mucosa/virology , Respiratory System/drug effects , Respiratory System/immunology , Respiratory System/metabolism , Respiratory System/virology , Vero Cells , Viral Load/drug effects , Virus Replication/drug effects
20.
PLoS One ; 16(5): e0251913, 2021.
Article in English | MEDLINE | ID: covidwho-1232467

ABSTRACT

Last decade has witnessed three major pandemics caused by SARS-CoV, SARS-CoV-2 and MERS-CoV that belong to Coronavirus family. Currently, there are no effective therapies available for corona virus infections. Since the three viruses belong to the same family and share many common features, we can theoretically design a drug that can be effective on all the three of them. In this study, using computational approach, we designed a peptide (Peptide 7) that can bind to the Receptor Binding Domain (RBD) of SARS-CoV, SARS-CoV-2 and MERS-CoV thereby preventing the entry of the viruses into the host cell. The peptide inhibitor was designed as a consensus peptide from three different peptides that might individually bind to the RBD of the three viruses. Docking studies and molecular dynamic simulations using Peptide 7 has shown that it binds with higher affinity than the native receptors of the RBD and forms a stable complex thereby preventing further viral-receptor interaction and inhibiting their cellular entry. This effective binding is observed for the three RBDs, despite the Peptide 7 interactions being slightly different. Hence; this peptide inhibitor can be used as a potential candidate for the development of peptide based anti-viral therapy against Corona viruses.


Subject(s)
Middle East Respiratory Syndrome Coronavirus/physiology , Peptides/pharmacology , SARS Virus/physiology , SARS-CoV-2/physiology , Virus Internalization/drug effects , Amino Acid Sequence , Binding Sites , Humans , Hydrogen Bonding , Middle East Respiratory Syndrome Coronavirus/metabolism , Molecular Docking Simulation , Molecular Dynamics Simulation , Peptides/chemistry , Peptides/metabolism , Protein Binding , Receptors, Virus/chemistry , Receptors, Virus/metabolism , SARS Virus/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
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