New Scientist
Volume 245, Issue 3275, 28 March 2020, Pages 10-11
It is easy to spread the virus without realising you are ill, reports Graham Lawton
WITH more than 380,000 confirmed cases worldwide, one thing is clear about the new coronavirus: it is very good at infecting people. Now studies are starting to reveal just how infectious it is – and when a person with covid-19 is most likely to spread the virus.
Epidemiology
New Scientist
Volume 245, Issue 3275, March 2020, Pages 44-48
There has never been a more important time to keep your immune system fit and healthy. And as Graham Lawton discovers, there are now ways to keep it younger than you are.
WASH your hands religiously for 20 seconds, sneeze into your elbow, avoid touching your face, stay 1 meter away from all other people and, as a last resort, self-quarantine for a week with only your emergency rations for company. If you want to avoid getting the new coronavirus, all of these are a good idea. But ultimately, one of the most important things standing between you and a deadly bout of COVID-19 is your immune system.
Epidemiology
Brazilian Journal of Anesthesiology (English Edition)
In December 2019, China reported clusters of pneumonia in the city of Wuhan, epidemiologically related to transmission from animals. On December, 31, 2019, the Center for Disease Control and Prevention of China described a new coronavirus and announced the first stage of an outbreak. In addition to coronavirus SARS-CoV and coronavirus MERS-CoV, the world would be facing a new virus that was named SARS-CoV-2, which could lead to a severe acute respiratory syndrome and was named by the World Health Organization Covid-19 (Coronavirus Disease 2019).
Epidemiology
Journal of Pharmaceutical Analysis
5 March 2020
Coronavirus disease 2019 (COVID-19) is a kind of viral pneumonia with an unusual outbreak in Wuhan, China, in December 2019, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The emergence of SARS-CoV-2 has been marked as the third introduction of a highly pathogenic coronavirus into the human population after the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) in the twenty-first century. In this minireview, we provide a brief introduction of the general features of SARS-CoV-2 and discuss current knowledge of molecular immune pathogenesis, diagnosis and treatment of COVID-19 on the base of the present understanding of SARS-CoV and MERS-CoV infections, which may be helpful in offering novel insights and potential therapeutic targets for combating the SARS-CoV-2 infection.
Coronavirus, SARS-CoV-2, SARS-CoV, MERS-CoV, Pathogenesis
Antiviral Research
Volume 141, May 2017, Pages 101-106
Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe acute respiratory illness with fever, cough and shortness of breath. Up to date, it has resulted in 1826 human infections, including 649 deaths. Analogous to picornavirus 3C protease (3Cpro), 3C-like protease (3CLpro) is critical for initiation of the MERS-CoV replication cycle and is thus regarded as a validated drug target. As presented here, our peptidomimetic inhibitors of enterovirus 3Cpro (6b, 6c and 6d) inhibited 3CLpro of MERS-CoV and severe acute respiratory syndrome coronavirus (SARS-CoV) with IC50 values ranging from 1.7 to 4.7 μM and from 0.2 to 0.7 μM, respectively. In MERS-CoV-infected cells, the inhibitors showed antiviral activity with EC50 values ranging from 0.6 to 1.4 μM, by downregulating the viral protein production in cells as well as reducing secretion of infectious viral particles into culture supernatants. They also suppressed other α- and β-CoVs from human and feline origin. These compounds exhibited good selectivity index (over 70 against MERS-CoV) and could lead to the development of broad-spectrum antiviral drugs against emerging CoVs and picornaviruses.
MERS-CoV, SARS-CoV, 3C-like protease, Peptidomimetic inhibitor, Coronavirus, Picornavirus
Cell Host and Microbes
Volume 21, Issue 3, 8 March 2017, Pages 344-355
Severe acute respiratory syndrome coronavirus (SARS-CoV) causes lethal disease in humans, which is characterized by exacerbated inflammatory response and extensive lung pathology. To address the relevance of small non-coding RNAs in SARS-CoV pathology, we deep sequenced RNAs from the lungs of infected mice and discovered three 18–22 nt small viral RNAs (svRNAs). The three svRNAs were derived from the nsp3 (svRNA-nsp3.1 and -nsp3.2) and N (svRNA-N) genomic regions of SARS-CoV. Biogenesis of CoV svRNAs was RNase III, cell type, and host species independent, but it was dependent on the extent of viral replication. Antagomir-mediated inhibition of svRNA-N significantly reduced in vivo lung pathology and pro-inflammatory cytokine expression. Taken together, these data indicate that svRNAs contribute to SARS-CoV pathogenesis and highlight the potential of svRNA-N antagomirs as antivirals.
coronavirus, SARS-CoV, small viral RNAs, virus-host interaction, lung inflammatory pathology, antagomirs, deep sequencing, non-coding RNAs, innate immune response, antiviral
Antiviral Research
Volume 137, January 2017, Pages 82-92
Over 12 years have elapsed since severe acute respiratory syndrome (SARS) triggered the first global alert for coronavirus infections. Virus transmission in humans was quickly halted by public health measures and human infections of SARS coronavirus (SARS-CoV) have not been observed since. However, other coronaviruses still pose a continuous threat to human health, as exemplified by the recent emergence of Middle East respiratory syndrome (MERS) in humans. The work on SARS-CoV widens our knowledge on the epidemiology, pathophysiology and immunology of coronaviruses and may shed light on MERS coronavirus (MERS-CoV). It has been confirmed that T-cell immunity plays an important role in recovery from SARS-CoV infection. Herein, we summarize T-cell immunological studies of SARS-CoV and discuss the potential cross-reactivity of the SARS-CoV-specific immunity against MERS-CoV, which may provide useful recommendations for the development of broad-spectrum vaccines against coronavirus infections.
SARS-CoV, MERS-CoV, Vaccine, T-cell, Epitope, Cross-reactivity
Trends in Microbiology
Volume 23, Issue 8, August 2015, Pages 468-478
Both severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) are zoonotic pathogens that crossed the species barriers to infect humans. The mechanism of viral interspecies transmission is an important scientific question to be addressed. These coronaviruses contain a surface-located spike (S) protein that initiates infection by mediating receptor-recognition and membrane fusion and is therefore a key factor in host specificity. In addition, the S protein needs to be cleaved by host proteases before executing fusion, making these proteases a second determinant of coronavirus interspecies infection. Here, we summarize the progress made in the past decade in understanding the cross-species transmission of SARS-CoV and MERS-CoV by focusing on the features of the S protein, its receptor-binding characteristics, and the cleavage process involved in priming.
coronavirus, interspecies transmission, viral and host determinants, spike (S), SARS-CoV, MERS-CoV
Virology
Volumes 479–480, May 2015, Pages 247-258
Two novel coronaviruses have emerged to cause severe disease in humans. While bats may be the primary reservoir for both viruses, SARS coronavirus (SARS-CoV) likely crossed into humans from civets in China, and MERS coronavirus (MERS-CoV) has been transmitted from camels in the Middle East. Unlike SARS-CoV that resolved within a year, continued introductions of MERS-CoV present an on-going public health threat. Animal models are needed to evaluate countermeasures against emerging viruses. With SARS-CoV, several animal species were permissive to infection. In contrast, most laboratory animals are refractory or only semi-permissive to infection with MERS-CoV. This host-range restriction is largely determined by sequence heterogeneity in the MERS-CoV receptor. We describe animal models developed to study coronaviruses, with a focus on host-range restriction at the level of the viral receptor and discuss approaches to consider in developing a model to evaluate countermeasures against MERS-CoV.
Coronaviruses, SARS-CoV, MERS-CoV, Animal models, Receptor
Virus Research
Volume 194, 19 December 2014, Pages 124-137
Coronavirus (CoV) infection is usually detected by cellular sensors, which trigger the activation of the innate immune system. Nevertheless, CoVs have evolved viral proteins that target different signaling pathways to counteract innate immune responses. Some CoV proteins act as antagonists of interferon (IFN) by inhibiting IFN production or signaling, aspects that are briefly addressed in this review. After CoV infection, potent cytokines relevant in controlling virus infections and priming adaptive immune responses are also generated. However, an uncontrolled induction of these proinflammatory cytokines can lead to pathogenesis and disease severity as described for SARS-CoV and MERS-CoV. The cellular pathways mediated by interferon regulatory factor (IRF)-3 and -7, activating transcription factor (ATF)-2/jun, activator protein (AP)-1, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and nuclear factor of activated T cells (NF-AT), are the main drivers of the inflammatory response triggered after viral infections, with NF-κB pathway the most frequently activated. Key CoV proteins involved in the regulation of these pathways and the proinflammatory immune response are revisited in this manuscript.
It has been shown that the envelope (E) protein plays a variable role in CoV morphogenesis, depending on the CoV genus, being absolutely essential in some cases (genus α CoVs such as TGEV, and genus β CoVs such as MERS-CoV), but not in others (genus β CoVs such as MHV or SARS-CoV). A comprehensive accumulation of data has shown that the relatively small E protein elicits a strong influence on the interaction of SARS-CoV with the host. In fact, after infection with viruses in which this protein has been deleted, increased cellular stress and unfolded protein responses, apoptosis, and augmented host immune responses were observed. In contrast, the presence of E protein activated a pathogenic inflammatory response that may cause death in animal models and in humans.
The modification or deletion of different motifs within E protein, including the transmembrane domain that harbors an ion channel activity, small sequences within the middle region of the carboxy-terminus of E protein, and its most carboxy-terminal end, which contains a PDZ domain-binding motif (PBM), is sufficient to attenuate the virus. Interestingly, a comprehensive collection of SARS-CoVs in which these motifs have been modified elicited full and long-term protection even in old mice, making those deletion mutants promising vaccine candidates. These data indicate that despite its small size, E protein drastically influences the replication of CoVs and their pathogenicity. Although E protein is not essential for CoV genome replication or subgenomic mRNA synthesis, it affects virus morphogenesis, budding, assembly, intracellular trafficking, and virulence. In fact, E protein is responsible in a significant proportion of the inflammasome activation and the associated inflammation elicited by SARS-CoV in the lung parenchyma. This exacerbated inflammation causes edema accumulation leading to acute respiratory distress syndrome (ARDS) and, frequently, to the death of infected animal models or human patients.
Coronavirus, SARS-CoV, MERS-CoV, Innate immunity, Inflammation, Envelope protein
Travel Medicine and Infectious Disease
Volume 12, Issue 5, September–October 2014, Pages 422-428
The emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and of the Middle East Syndrome Cornavirus (MERS-CoV) caused widespread fear and concern for their potential threat to global health security. There are similarities and differences in the epidemiology and clinical features between these two diseases. The origin of SARS-COV and MERS-CoV is thought to be an animal source with subsequent transmission to humans. The identification of both the intermediate host and the exact route of transmission of MERS-CoV is crucial for the subsequent prevention of the introduction of the virus into the human population. So far MERS-CoV had resulted in a limited travel-associated human cases with no major events related to the Hajj.
MERS-CoV, SARS-CoV, Hajj: zoonosis, Travel
Microbes and Infection
Volume 15, Issues 8–9, July–August 2013, Pages 625-629
Middle East respiratory syndrome coronavirus (MERS-CoV), a novel human coronavirus that caused outbreaks of a SARS-like illness in the Middle East, is now considered a threat to global public health. This review discusses the challenges in identifying the source of this fatal virus and developing effective and safe anti-MERS-CoV vaccines and therapeutics in order to control its spread and to combat any future pandemic.
Coronavirus, MERS-CoV, SARS-CoV, Source, Vaccine, Therapeutics
Bioorganic & Medicinal Chemistry
Volume 21, Issue 13, 1 July 2013, Pages 3730-3737
SARS-CoV 3CLpro plays an important role in viral replication. In this study, we performed a biological evaluation on nine phlorotannins isolated from the edible brown algae Ecklonia cava. The nine isolated phlorotannins (1–9), except phloroglucinol (1), possessed SARS-CoV 3CLpro inhibitory activities in a dose-dependently and competitive manner. Of these phlorotannins (1–9), two eckol groups with a diphenyl ether linked dieckol (8) showed the most potent SARS-CoV 3CLpro trans/cis-cleavage inhibitory effects (IC50s = 2.7 and 68.1 μM, respectively). This is the first report of a (8) phlorotannin chemotype significantly blocking the cleavage of SARS-CoV 3CLpro in a cell-based assay with no toxicity. Furthermore, dieckol (8) exhibited a high association rate in the SPR sensorgram and formed extremely strong hydrogen bonds to the catalytic dyad (Cys145 and His41) of the SARS-CoV 3CLpro.
Phlorotannin, SARS-CoV, Dieckol, Eckol, Ecklonia cava
Bioorganic & Medicinal Chemistry
Volume 20, Issue 19, 1 October 2012, Pages 5928-5935
In the search for anti-SARS-CoV, tanshinones derived from Salvia miltiorrhiza were found to be specific and selective inhibitors for the SARS-CoV 3CLpro and PLpro, viral cysteine proteases. A literature search for studies involving the seven isolated tanshinone hits showed that at present, none have been identified as coronaviral protease inhibitors. We have identified that all of the isolated tanshinones are good inhibitors of both cysteine proteases. However, their activity was slightly affected by subtle changes in structure and targeting enzymes. All isolated compounds (1–7) act as time dependent inhibitors of PLpro, but no improved inhibition was observed following preincubation with the 3CLpro. In a detail kinetic mechanism study, all of the tanshinones except rosmariquinone (7) were identified as noncompetitive enzyme isomerization inhibitors. However, rosmariquinone (7) showed a different kinetic mechanism through mixed-type simple reversible slow-binding inhibition. Furthermore, tanshinone I (5) exhibited the most potent nanomolar level inhibitory activity toward deubiquitinating (IC50 = 0.7 μM). Additionally, the inhibition is selective because these compounds do not exert significant inhibitory effects against other proteases including chymotrysin, papain, and HIV protease. These findings provide potential inhibitors for SARS-CoV viral infection and replication.
Tanshinone, SARS-CoV, 3CLpro, PLpro, Slow-binding inhibitor
Virus Research
Volume 165, Issue 1, April 2012, Pages 112-117
Recent research has shown that Coronavirus (CoV) replication depends on active immunophilin pathways. Here we demonstrate that the drug FK506 (Tacrolimus) inhibited strongly the growth of human coronaviruses SARS-CoV, HCoV-NL63 and HCoV-229E at low, non-cytotoxic concentrations in cell culture. As shown by plaque titration, qPCR, Luciferase- and green fluorescent protein (GFP) reporter gene expression, replication was diminished by several orders of magnitude. Knockdown of the cellular FK506-binding proteins FKBP1A and FKBP1B in CaCo2 cells prevented replication of HCoV-NL63, suggesting the requirement of these members of the immunophilin family for virus growth.
SARS-CoV, HCoV-NL63, HCoV-229E, FK506, Tacrolimus, Immunophilins, FKBP1A (FKBP12), FKBP1B (FKBP12.6), Inhibition of viral replication
Poultry Science
Volume 91, Issue 3, 1 March 2012, Pages 636-642
The goal of this study was to develop a quantitative detection system for severe acute respiratory syndrome-associated coronavirus (SARS-CoV), targeting the nucleocapsid protein (NP), to determine the presence and degree of infection in suspected individuals. Because the NP is the viral protein shed during infection and its template mRNA is the most abundant subgenomic RNA, it is a suitable candidate for developing antibodies for diagnostic applications. In this study, we have prepared full-length SARS-CoV NP expressed in Escherichia coli and purified. Full-length NP was used for the preparation of mouse monoclonal antibody and chicken polyclonal IgY antibodies for the development of heterosandwich ELISA for early diagnostics of SARS-suspected individuals. The sensitivity of the developed heterosandwich ELISA can detect the viral antigen at 18.5 pg/mL of recombinant NP. This study describes ultrasensitive ELISA using 19B6 monoclonal antibody as the capture antibody and IgY as the detecting antibody against the most abundant SARS-CoV NP antigens. One of the most important findings was the use of inexpensive polyclonal IgY antibody to increase the sensitivity of the detection system for SARS-CoV at the picogram level. Furthermore, the immunoassay of SARS-CoV NP antigen developed could be an effective and sensitive method of diagnosing SARS-suspected individuals during a future SARS-CoV outbreak.
SARS-CoV, nucleocapsid protein, 19B6 monoclonal antibody, immunoglobulin Y, heterosandwich ELISA
Virus Research
Volume 165, Issue 1, April 2012, Pages 112-117
Recent research has shown that Coronavirus (CoV) replication depends on active immunophilin pathways. Here we demonstrate that the drug FK506 (Tacrolimus) inhibited strongly the growth of human coronaviruses SARS-CoV, HCoV-NL63 and HCoV-229E at low, non-cytotoxic concentrations in cell culture. As shown by plaque titration, qPCR, Luciferase- and green fluorescent protein (GFP) reporter gene expression, replication was diminished by several orders of magnitude. Knockdown of the cellular FK506-binding proteins FKBP1A and FKBP1B in CaCo2 cells prevented replication of HCoV-NL63, suggesting the requirement of these members of the immunophilin family for virus growth.
SARS-CoV, HCoV-NL63, HCoV-229E, FK506, Tacrolimus, Immunophilins, FKBP1A (FKBP12), FKBP1B, (FKBP12.6), Inhibition of viral replication
Antiviral Research
Volume 85, Issue 3, March 2010, Pages 551-555
Because outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) might reemerge, identifying antiviral compounds is of key importance. Previously, we showed that the cellular factor TNF-α converting enzyme (TACE), activated by the spike protein of SARS-CoV (SARS-S protein), was positively involved in viral entry, implying that TACE is a possible target for developing antiviral compounds. To demonstrate this possibility, we here tested the effects of TACE inhibitors on viral entry. In vitro and in vivo data revealed that the TACE inhibitor TAPI-2 attenuated entry of both pseudotyped virus expressing the SARS-S protein in a lentiviral vector backbone and infectious SARS-CoV. TAPI-2 blocked both the SARS-S protein-induced shedding of angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV, and TNF-α production in lung tissues. Since the downregulation of ACE2 by SARS-S protein was proposed as an etiological event in the severe clinical manifestations, our data suggest that TACE antagonists block SARS-CoV infection and also attenuate its severe clinical outcome.
SARS-CoV, TACE, ACE2, Shedding
Bioorganic & Medicinal Chemistry Letters
Volume 20, Issue 6, 15 March 2010, Pages 1873-1876
Quinone-methide triterpenes, celastrol (1), pristimerin (2), tingenone (3), and iguesterin (4) were isolated from Triterygium regelii and dihydrocelastrol (5) was synthesized by hydrogenation under palladium catalyst. Isolated quinone-methide triterpenes (1–4) and 5 were evaluated for SARS-CoV 3CLpro inhibitory activities and showed potent inhibitory activities with IC50 values of 10.3, 5.5, 9.9, and 2.6 μM, respectively, whereas the corresponding 5 having phenol moiety was observed in low activity (IC50 = 21.7 μM). As a result, quinone-methide moiety in A-ring and more hydrophobic E-ring assist to exhibit potent activity. Also, all quinone-methide triterpenes 1–4 have proven to be competitive by the kinetic analysis.
SARS-CoV, 3CLpro, Tripterygium regelii, Quinone-methide, Celastrol, Iguesterin
Virology
Volume 405, Issue 1, 15 September 2010, Pages 139-148
Coronaviruses are enveloped RNA viruses that generally cause mild disease in humans. However, the recently emerged coronavirus that caused severe acute respiratory syndrome (SARS-CoV) is the most pathogenic human coronavirus discovered to date. The SARS-CoV spike (S) protein mediates virus entry by binding cellular receptors and inducing fusion between the viral envelope and the host cell membrane. Coronavirus S proteins are palmitoylated, which may affect function. Here, we created a non-palmitoylated SARS-CoV S protein by mutating all nine cytoplasmic cysteine residues. Palmitoylation of SARS-CoV S was required for partitioning into detergent-resistant membranes and for cell–cell fusion. Surprisingly, however, palmitoylation of S was not required for interaction with SARS-CoV M protein. This contrasts with the requirement for palmitoylation of mouse hepatitis virus S protein for interaction with M protein and may point to important differences in assembly and infectivity of these two coronaviruses.
coronavirus, SARS-CoV, spike, palmitoylation, fusion, detergent-resistant membranes, trafficking