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1.
Biosensors and Bioelectronics ; : 114222, 2022.
Article in English | ScienceDirect | ID: covidwho-1778011

ABSTRACT

The 21st century has already brought us a plethora of new threats related to viruses that emerge in humans after zoonotic transmission or drastically change their geographic distribution or prevalence. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first spotted at the end of 2019 to rapidly spread in southwest Asia and later cause a global pandemic, which paralyzes the world since then. We have designed novel immunosensors targeting conserved protein sequences of the N protein of SARS-CoV-2 based on lab-produced and purified anti-SARS-CoV-2 nucleocapsid antibodies that are densely grafted onto various surfaces (diamond/gold/glassy carbon). Titration of antibodies shows very strong reactions up to 1:72 900 dilution. Next, we showed the mechanism of interactions of our immunoassay with nucleocapsid N protein revealing molecular recognition by impedimetric measurements supported by hybrid modeling results with both density functional theory and molecular dynamics methods. Biosensors allowed for a fast (in less than 10 min) detection of SARS-CoV-2 virus with a limit of detection from 0.227 ng/ml through 0.334 ng/ml to 0.362 ng/ml for glassy carbon, boron-doped diamond, and gold surfaces, respectively. For all tested surfaces, we obtained a wide linear range of concentrations from 4.4 ng/ml to 4.4 pg/ml. Furthermore, our sensor leads to a highly specific response to SARS-CoV-2 clinical samples versus other upper respiratory tract viruses such as influenza, respiratory syncytial virus, or Epstein-Barr virus. All clinical samples were tested simultaneously on biosensors and real-time polymerase chain reactions.

2.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327735

ABSTRACT

During the RNA replication, coronaviruses require proofreading to maintain the integrity of their large genomes. Nsp14 associates with viral polymerase complex to excise the mismatched nucleotides. Aside from the exonuclease activity, nsp14 methyltransferase domain mediates cap methylation, facilitating translation initiation and protecting viral RNA from recognition by the innate immune sensors. The nsp14 exonuclease activity is modulated by a protein co-factor nsp10. While the nsp10/nsp14 complex structure is available, the mechanistic basis for nsp10 mediated modulation remains unclear in the absence of nsp14 structure. Here we provide a crystal structure of nsp14 in an apo-form. Comparative analysis of the apo- and nsp10 bound structures explain the modulatory role of the co-factor protein. Further, the structure presented in this study rationalizes the recently proposed idea of nsp14/nsp10/nsp16 ternary complex.

3.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327128

ABSTRACT

Coronaviruses protect their single-stranded RNA genome with the methylated cap added during the replication. This capping process is carried out by several nonstructural proteins (nsp) encoded in the viral genome. The methylation itself is performed consecutively by two methyltransferases, nsp14 and nsp16, which interact with nsp10 protein acting as a co-factor. The nsp14 protein also carries the exonuclease domain, which also serves as a part of the proofreading system during the replication of the large RNA genome. The available crystal structures suggest that the concomitant interaction between these three proteins is impossible due to the structural clash, and it is generally accepted that the nsp16 and nsp14 bind with the nsp10 separately. Here, we show that nsp14, nsp10, and nsp16 form a methylation complex despite the odds. Due to spatial proximity, this interaction is beneficial for forming mature capped viral mRNA. Further, it modulates the exonuclease activity of nsp14, protecting the viral RNA at the replication site. Our findings show that nsp14 is more amenable to allosteric regulation and may serve as a molecular target for the therapy.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-320685

ABSTRACT

New Ebselen-like derivatives resulted to be very strong in vitro inhibitors of SARS-CoV-2 main protease. We demonstrated that this activity mainly depends on the electrophilicity of the selenium atom that is considerably higher in the N-substituted 1,2- benzoselenazol-3(2H)-ones respect to the corresponding diselenides allowing it to be rapidly attached by free thiols affording sulfur-selenium intermediates that are further subjected to thiol exchange processes. This data paints a very complex scenario that requires us to consider Ebselen and Ebselen-like derivatives as potential electrophilic substrates for the several other free thiols present in the cell beside the target free cysteine. The sulfur selenium intermediates are milder electrophiles that could be theoretically implicated in both the detoxification process as well as in the final enzymatic inhibition. We here demonstrated that the in vitro inhibition activity is not fully reproduced in the prevention of viral replication in the cell-based assay. This indicates that the structure of the substituents introduced in the Ebselen scaffold is a crucial factor to control the reactivity of the selenated molecule in the network of thiol exchanges, as well as for molecular recognition of the targeted enzymatic cysteine. For this reason, an in-depth investigation is strongly desirable to better understand how to increase the activity and the selectivity of Ebselen derivatives overcoming the issues of the apparent PAINS-like role of Ebselen. Furthermore, besides the antiviral activity, thee selected compounds also showed a different ability to reduce the virus-induced cytopathic effect, indicating that other mechanisms could be implicated. One may consider here the well-known cytoprotective antioxidant activity of Ebselen and its derivatives.

5.
Clin Microbiol Infect ; 28(3): 451.e1-451.e4, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1623323

ABSTRACT

OBJECTIVES: This work aimed to analyse possible zoonotic spill-over of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We report the spill-over of mink-adapted SARS-CoV-2 from farmed mink to humans after adaptation that lasted at least 3 months. METHODS: Next-generation sequencing and a bioinformatic approach were applied to analyse the data. RESULTS: In an isolate obtained from an asymptomatic patient testing positive for SARS-CoV-2, we found four distinguishing mutations in the S gene that gave rise to the mink-adapted variant (G75V, M177T, Y453F, and C1247F) and others. CONCLUSIONS: Zoonotic spill-over of SARS-CoV-2 can occur from mink to human.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , COVID-19/veterinary , Farms , Humans , Mink , SARS-CoV-2/genetics , Zoonoses
6.
Cell Chem Biol ; 2022 Jan 11.
Article in English | MEDLINE | ID: covidwho-1616412

ABSTRACT

The COVID-19 pandemic caused by SARS-CoV-2 has been socially and economically devastating. Despite an unprecedented research effort and available vaccines, effective therapeutics are still missing to limit severe disease and mortality. Using high-throughput screening, we identify acriflavine (ACF) as a potent papain-like protease (PLpro) inhibitor. NMR titrations and a co-crystal structure confirm that acriflavine blocks the PLpro catalytic pocket in an unexpected binding mode. We show that the drug inhibits viral replication at nanomolar concentration in cellular models, in vivo in mice and ex vivo in human airway epithelia, with broad range activity against SARS-CoV-2 and other betacoronaviruses. Considering that acriflavine is an inexpensive drug approved in some countries, it may be immediately tested in clinical trials and play an important role during the current pandemic and future outbreaks.

7.
Cells ; 10(11)2021 11 13.
Article in English | MEDLINE | ID: covidwho-1512139

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the recently emerged virus responsible for the COVID-19 pandemic. Clinical presentation can range from asymptomatic disease and mild respiratory tract infection to severe disease with lung injury, multiorgan failure, and death. SARS-CoV-2 is the third animal coronavirus to emerge in humans in the 21st century, and coronaviruses appear to possess a unique ability to cross borders between species and infect a wide range of organisms. This is somewhat surprising as, except for the requirement of host cell receptors, cell-pathogen interactions are usually species-specific. Insights into these host-virus interactions will provide a deeper understanding of the process of SARS-CoV-2 infection and provide a means for the design and development of antiviral agents. In this study, we describe a complex analysis of SARS-CoV-2 infection using a genome-wide CRISPR-Cas9 knock-out system in HeLa cells overexpressing entry receptor angiotensin-converting enzyme 2 (ACE2). This platform allows for the identification of factors required for viral replication. This study was designed to include a high number of replicates (48 replicates; 16 biological repeats with 3 technical replicates each) to prevent data instability, remove sources of bias, and allow multifactorial bioinformatic analyses in order to study the resulting interaction network. The results obtained provide an interesting insight into the replication mechanisms of SARS-CoV-2.


Subject(s)
SARS-CoV-2/physiology , Virus Replication , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , CRISPR-Cas Systems , Computational Biology , Genome, Human/genetics , HeLa Cells , Host-Pathogen Interactions , Humans , SARS-CoV-2/pathogenicity
8.
Front Microbiol ; 12: 732998, 2021.
Article in English | MEDLINE | ID: covidwho-1506502

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a major epidemic threat since the beginning of 2020. Efforts to combat the virus and the associated coronavirus disease 2019 (COVID-19) disease are being undertaken worldwide. To facilitate the research on the virus itself, a number of surrogate systems have been developed. Here, we report the efficient production of SARS-CoV-2 virus-like particles (VLPs) in insect cells. Contrary to widely used pseudovirus particles, where only one coronaviral protein is displayed within a heterologous scaffold, developed VLPs are structurally similar to the native virus and allow for more throughput studies on the biology of the infection. On the other hand, being devoid of the viral genome, VLPs are unable to replicate and thus safe to work with. Importantly, this is the first report showing that SARS-CoV-2 VLPs can be efficiently produced in insect cells and purified using scalable affinity chromatography.

9.
Molecules ; 26(19)2021 Oct 07.
Article in English | MEDLINE | ID: covidwho-1463770

ABSTRACT

The COVID-19 pandemic outbreak prompts an urgent need for efficient therapeutics, and repurposing of known drugs has been extensively used in an attempt to get to anti-SARS-CoV-2 agents in the shortest possible time. The glycoside rutin shows manifold pharmacological activities and, despite its use being limited by its poor solubility in water, it is the active principle of many pharmaceutical preparations. We herein report our in silico and experimental investigations of rutin as a SARS-CoV-2 Mpro inhibitor and of its water solubility improvement obtained by mixing it with l-arginine. Tests of the rutin/l-arginine mixture in a cellular model of SARS-CoV-2 infection highlighted that the mixture still suffers from unfavorable pharmacokinetic properties, but nonetheless, the results of this study suggest that rutin might be a good starting point for hit optimization.


Subject(s)
Antiviral Agents/pharmacology , Arginine/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Rutin/pharmacology , SARS-CoV-2/drug effects , A549 Cells , Coronavirus 3C Proteases/metabolism , Humans , Molecular Docking Simulation , Protease Inhibitors/pharmacology , SARS-CoV-2/metabolism , Solubility
10.
Sci Rep ; 11(1): 20012, 2021 10 08.
Article in English | MEDLINE | ID: covidwho-1462029

ABSTRACT

There are currently no cures for coronavirus infections, making the prevention of infections the only course open at the present time. The COVID-19 pandemic has been difficult to prevent, as the infection is spread by respiratory droplets and thus effective, scalable and safe preventive interventions are urgently needed. We hypothesise that preventing viral entry into mammalian nasal epithelial cells may be one way to limit the spread of COVID-19. Here we show that N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan (GCPQ), a positively charged polymer that has been through an extensive Good Laboratory Practice toxicology screen, is able to reduce the infectivity of SARS-COV-2 in A549ACE2+ and Vero E6 cells with a log removal value of - 3 to - 4 at a concentration of 10-100 µg/ mL (p < 0.05 compared to untreated controls) and to limit infectivity in human airway epithelial cells at a concentration of 500 µg/ mL (p < 0.05 compared to untreated controls). In vivo studies using transgenic mice expressing the ACE-2 receptor, dosed nasally with SARS-COV-2 (426,000 TCID50/mL) showed a trend for nasal GCPQ (20 mg/kg) to inhibit viral load in the respiratory tract and brain, although the study was not powered to detect statistical significance. GCPQ's electrostatic binding to the virus, preventing viral entry into the host cells, is the most likely mechanism of viral inhibition. Radiolabelled GCPQ studies in mice show that at a dose of 10 mg/kg, GCPQ has a long residence time in mouse nares, with 13.1% of the injected dose identified from SPECT/CT in the nares, 24 h after nasal dosing. With a no observed adverse effect level of 18 mg/kg in rats, following a 28-day repeat dose study, clinical testing of this polymer, as a COVID-19 prophylactic is warranted.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Nasal Sprays , SARS-CoV-2/drug effects , A549 Cells , Animals , Antiviral Agents/administration & dosage , Chlorocebus aethiops , Humans , Male , Methylation , Mice, Inbred BALB C , Mice, Transgenic , SARS-CoV-2/physiology , Surface-Active Agents/administration & dosage , Surface-Active Agents/therapeutic use , Vero Cells , Viral Load/drug effects
11.
Euro Surveill ; 26(39)2021 09.
Article in English | MEDLINE | ID: covidwho-1448681

ABSTRACT

Routine genomic surveillance on samples from COVID-19 patients collected in Poland during summer 2021 revealed the emergence of a SARS-CoV-2 Delta variant with a large 872 nt deletion. This change, confirmed by Sanger and deep sequencing, causes complete loss of ORF7a, ORF7b, and ORF8 genes. The index case carrying the deletion is unknown. The standard pipeline for sequencing may mask this deletion with a long stretch of N's. Effects of this deletion on phenotype or immune evasion needs further study.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Poland
12.
Antioxidants (Basel) ; 10(9)2021 Sep 16.
Article in English | MEDLINE | ID: covidwho-1408381

ABSTRACT

COVID-19 caused by SARS-CoV-2 caused a worldwide crisis, highlighting the importance of preventive measures in infectious diseases control. SARS-CoV-2 can remain infectious on surfaces for up to several weeks; therefore, proper disinfection is required to mitigate the risk of indirect virus spreading. Gaseous ozone treatment has received particular attention as an easily accessible disinfection tool. In this study, we evaluated the virucidal effectiveness of gaseous ozone treatment (>7.3 ppm, 2 h) on murine hepatitis virus (MHV)-contaminated stainless-steel surface and PBS-suspended virus under field conditions at ambient (21.8%) and high (49.8-54.2%) relative humidity. Surficial virus was soiled with 0.3 g/L of BSA. Parallelly, a half-hour vaporization with 7.3% hydrogen peroxide was performed on contaminated carriers. The obtained results showed that gaseous ozone, whilst quite effective against suspended virus, was insufficient in sanitizing coronavirus contaminated surfaces, especially under low RH. Increased humidity created more favorable conditions for MHV inactivation, resulting in 2.1 log titre reduction. Vaporization with 7.3% hydrogen peroxide presented much better virucidal performance than ozonation in a similar experimental setup, indicating that its application may be more advantageous regarding gaseous disinfection of surfaces contaminated with other coronaviruses, including SARS-CoV-2.

13.
PLoS Pathog ; 16(12): e1008959, 2020 12.
Article in English | MEDLINE | ID: covidwho-1388958

ABSTRACT

SARS-CoV-2 genome annotation revealed the presence of 10 open reading frames (ORFs), of which the last one (ORF10) is positioned downstream of the N gene. It is a hypothetical gene, which was speculated to encode a 38 aa protein. This hypothetical protein does not share sequence similarity with any other known protein and cannot be associated with a function. While the role of this ORF10 was proposed, there is growing evidence showing that the ORF10 is not a coding region. Here, we identified SARS-CoV-2 variants in which the ORF10 gene was prematurely terminated. The disease was not attenuated, and the transmissibility between humans was maintained. Also, in vitro, the strains replicated similarly to the related viruses with the intact ORF10. Altogether, based on clinical observation and laboratory analyses, it appears that the ORF10 protein is not essential in humans. This observation further proves that the ORF10 should not be treated as the protein-coding gene, and the genome annotations should be amended.


Subject(s)
COVID-19/virology , Genome, Viral , Mutation , Open Reading Frames/genetics , SARS-CoV-2/genetics , Viral Proteins/genetics , Virus Replication , Adult , COVID-19/epidemiology , COVID-19/genetics , Codon, Nonsense , Female , Humans , In Vitro Techniques , Male , Middle Aged , Poland/epidemiology , SARS-CoV-2/isolation & purification , Viral Proteins/metabolism
15.
Vascul Pharmacol ; 130: 106680, 2020 07.
Article in English | MEDLINE | ID: covidwho-1386723

ABSTRACT

Angiotensin-converting enzyme (ACE) and its homologue, ACE2, have been mostly associated with hypertensive disorder. However, recent pandemia of SARS-CoV-2 has put these proteins at the center of attention, as this virus has been shown to exploit ACE2 protein to enter cells. Clear difference in the response of affected patients to this virus has urged researchers to find the molecular basis and pathophysiology of the cell response to this virus. Different levels of expression and function of ACE proteins, underlying disorders, consumption of certain medications and the existence of certain genomic variants within ACE genes are possible explanations for the observed difference in the response of individuals to the SARS-CoV-2 infection. In the current review, we discuss the putative mechanisms for this observation.


Subject(s)
Coronavirus Infections/enzymology , Peptidyl-Dipeptidase A/biosynthesis , Pneumonia, Viral/enzymology , COVID-19 , Coronavirus Infections/genetics , Coronavirus Infections/pathology , Humans , Pandemics , Peptidyl-Dipeptidase A/blood , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/genetics , Pneumonia, Viral/pathology
16.
Adv Respir Med ; 89(3): 328-333, 2021.
Article in English | MEDLINE | ID: covidwho-1291976

ABSTRACT

A 44-year-old male with no history of underlying diseases was referred to academic hospital due to ARDS with confirmed SARSCoV-2 infection after 7 days of mechanical ventilation. Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) was initiated as no improvement was noted in prone position. Mechanical ventilation was continued with TV of 3-4 mL/kg. A gradual decline of static lung compliance was observed from baseline 35 mL/cm H20 to 8 mL/cm H2O. The chest CT scan revealed extensive ground-glass areas with a significant amount of traction bronchiectasis after 3 weeks since admission. When the patient was negative for SARS-CoV-2 during the 4th week of ECMO, the decision to perform an emergency lung transplantation (LTx) was made based on the ongoing degradation of lung function and irreversible damage to lung structure. The patient was transferred to the transplant center where he was extubated, awaiting the transplant on passive oxygen therapy and ECMO. Double lung transplantation was performed on the day 30th of ECMO. Currently, the patient is self-reliant. He does not need oxygen therapy and continues physiotherapy. ECMO may be life-saving in severe cases of COVID-19 ARDS but some of these patients may require LTx, especially when weaning proves impossible. VV ECMO as a bridging method is more difficult but ultimately more beneficial due to insufficient number of donors, and consequently long waiting time in Poland.


Subject(s)
COVID-19/diagnostic imaging , COVID-19/surgery , Extracorporeal Membrane Oxygenation/methods , Lung Transplantation/methods , Respiratory Distress Syndrome/diagnostic imaging , Respiratory Distress Syndrome/surgery , COVID-19/complications , Humans , Male , Middle Aged , Poland , Time Factors , Tomography, X-Ray Computed
17.
Int J Mol Sci ; 22(13)2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1288904

ABSTRACT

The development of new antiviral drugs against SARS-CoV-2 is a valuable long-term strategy to protect the global population from the COVID-19 pandemic complementary to the vaccination. Considering this, the viral main protease (Mpro) is among the most promising molecular targets in light of its importance during the viral replication cycle. The natural flavonoid quercetin 1 has been recently reported to be a potent Mpro inhibitor in vitro, and we explored the effect produced by the introduction of organoselenium functionalities in this scaffold. In particular, we report here a new synthetic method to prepare previously inaccessible C-8 seleno-quercetin derivatives. By screening a small library of flavonols and flavone derivatives, we observed that some compounds inhibit the protease activity in vitro. For the first time, we demonstrate that quercetin (1) and 8-(p-tolylselenyl)quercetin (2d) block SARS-CoV-2 replication in infected cells at non-toxic concentrations, with an IC50 of 192 µM and 8 µM, respectively. Based on docking experiments driven by experimental evidence, we propose a non-covalent mechanism for Mpro inhibition in which a hydrogen bond between the selenium atom and Gln189 residue in the catalytic pocket could explain the higher Mpro activity of 2d and, as a result, its better antiviral profile.


Subject(s)
Antiviral Agents/chemistry , Quercetin/chemistry , SARS-CoV-2/metabolism , Selenium/chemistry , Viral Matrix Proteins/antagonists & inhibitors , Animals , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Binding Sites , COVID-19/pathology , COVID-19/virology , Catalytic Domain , Chlorocebus aethiops , Humans , Hydrogen Bonding , Molecular Docking Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protease Inhibitors/pharmacology , Quercetin/metabolism , Quercetin/pharmacology , SARS-CoV-2/isolation & purification , Selenium/metabolism , Vero Cells , Viral Matrix Proteins/metabolism , Virus Replication/drug effects
18.
Front Genet ; 12: 602196, 2021.
Article in English | MEDLINE | ID: covidwho-1177970

ABSTRACT

The heavy burden imposed by the COVID-19 pandemic on our society triggered the race toward the development of therapies or preventive strategies. Among these, antibodies and vaccines are particularly attractive because of their high specificity, low probability of drug-drug interaction, and potentially long-standing protective effects. While the threat at hand justifies the pace of research, the implementation of therapeutic strategies cannot be exempted from safety considerations. There are several potential adverse events reported after the vaccination or antibody therapy, but two are of utmost importance: antibody-dependent enhancement (ADE) and cytokine storm syndrome (CSS). On the other hand, the depletion or exhaustion of T-cells has been reported to be associated with worse prognosis in COVID-19 patients. This observation suggests a potential role of vaccines eliciting cellular immunity, which might simultaneously limit the risk of ADE and CSS. Such risk was proposed to be associated with FcR-induced activation of proinflammatory macrophages (M1) by Fu et al. (2020) and Iwasaki and Yang (2020). All aspects of the newly developed vaccine (including the route of administration, delivery system, and adjuvant selection) may affect its effectiveness and safety. In this work we use a novel in silico approach (based on AI and bioinformatics methods) developed to support the design of epitope-based vaccines. We evaluated the capabilities of our method for predicting the immunogenicity of epitopes. Next, the results of our approach were compared with other vaccine-design strategies reported in the literature. The risk of immuno-toxicity was also assessed. The analysis of epitope conservation among other Coronaviridae was carried out in order to facilitate the selection of peptides shared across different SARS-CoV-2 strains and which might be conserved in emerging zootic coronavirus strains. Finally, the potential applicability of the selected epitopes for the development of a vaccine eliciting cellular immunity for COVID-19 was discussed, highlighting the benefits and challenges of such an approach.

19.
Methods Mol Biol ; 2203: 241-261, 2020.
Article in English | MEDLINE | ID: covidwho-729911

ABSTRACT

Coronavirus entry encompasses the initial steps of infection, from virion attachment to genome release. Advances in fluorescent labeling of viral and cellular components and confocal imaging enable broad spectrum studies on this process. Here, we describe methods for visualization of coronavirus entry into immortalized cell lines and 3D tissue culture models.


Subject(s)
Coronavirus/pathogenicity , Host-Pathogen Interactions/physiology , Microscopy, Confocal/methods , Cell Line , Coronavirus/isolation & purification , Coronavirus Nucleocapsid Proteins , Culture Media/chemistry , Endocytosis , Humans , Nucleocapsid Proteins/metabolism , Triiodobenzoic Acids/chemistry , Virus Internalization
20.
Biomolecules ; 11(3)2021 03 22.
Article in English | MEDLINE | ID: covidwho-1151739

ABSTRACT

Global processes, such as climate change, frequent and distant travelling and population growth, increase the risk of viral infection spread. Unfortunately, the number of effective and accessible medicines for the prevention and treatment of these infections is limited. Therefore, in recent years, efforts have been intensified to develop new antiviral medicines or vaccines. In this review article, the structure and activity of the most promising antiviral cyanobacterial products are presented. The antiviral cyanometabolites are mainly active against the human immunodeficiency virus (HIV) and other enveloped viruses such as herpes simplex virus (HSV), Ebola or the influenza viruses. The majority of the metabolites are classified as lectins, monomeric or dimeric proteins with unique amino acid sequences. They all show activity at the nanomolar range but differ in carbohydrate specificity and recognize a different epitope on high mannose oligosaccharides. The cyanobacterial lectins include cyanovirin-N (CV-N), scytovirin (SVN), microvirin (MVN), Microcystisviridis lectin (MVL), and Oscillatoria agardhii agglutinin (OAA). Cyanobacterial polysaccharides, peptides, and other metabolites also have potential to be used as antiviral drugs. The sulfated polysaccharide, calcium spirulan (CA-SP), inhibited infection by enveloped viruses, stimulated the immune system's response, and showed antitumor activity. Microginins, the linear peptides, inhibit angiotensin-converting enzyme (ACE), therefore, their use in the treatment of COVID-19 patients with injury of the ACE2 expressing organs is considered. In addition, many cyanobacterial extracts were revealed to have antiviral activities, but the active agents have not been identified. This fact provides a good basis for further studies on the therapeutic potential of these microorganisms.


Subject(s)
Antiviral Agents/chemistry , Cyanobacteria/chemistry , HIV/drug effects , Lectins/pharmacology , Polysaccharides/pharmacology , SARS-CoV-2/drug effects , Simplexvirus/drug effects , Anti-HIV Agents/pharmacology , Antineoplastic Agents/pharmacology , Antiviral Agents/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/pharmacology , COVID-19/drug therapy , Carbohydrates/chemistry , Carbohydrates/pharmacology , Cyanobacteria/metabolism , HIV Infections/drug therapy , Humans , Lectins/chemistry , Lectins/metabolism , Polysaccharides/chemistry , Polysaccharides/metabolism
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