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1.
Travel Med Infect Dis ; 37: 101873, 2020.
Article in English | MEDLINE | ID: covidwho-2247060

ABSTRACT

In December 2019, a new severe acute respiratory syndrome coronavirus (SARS-CoV-2) causing coronavirus diseases 2019 (COVID-19) emerged in Wuhan, China. African countries see slower dynamic of COVID-19 cases and deaths. One of the assumptions that may explain this later emergence in Africa, and more particularly in malaria endemic areas, would be the use of antimalarial drugs. We investigated the in vitro antiviral activity against SARS-CoV-2 of several antimalarial drugs. Chloroquine (EC50 = 2.1 µM and EC90 = 3.8 µM), hydroxychloroquine (EC50 = 1.5 µM and EC90 = 3.0 µM), ferroquine (EC50 = 1.5 µM and EC90 = 2.4 µM), desethylamodiaquine (EC50 = 0.52 µM and EC90 = 1.9 µM), mefloquine (EC50 = 1.8 µM and EC90 = 8.1 µM), pyronaridine (EC50 = 0.72 µM and EC90 = 0.75 µM) and quinine (EC50 = 10.7 µM and EC90 = 38.8 µM) showed in vitro antiviral effective activity with IC50 and IC90 compatible with drug oral uptake at doses commonly administered in malaria treatment. The ratio Clung/EC90 ranged from 5 to 59. Lumefantrine, piperaquine and dihydroartemisinin had IC50 and IC90 too high to be compatible with expected plasma concentrations (ratio Cmax/EC90 < 0.05). Based on our results, we would expect that countries which commonly use artesunate-amodiaquine or artesunate-mefloquine report fewer cases and deaths than those using artemether-lumefantrine or dihydroartemisinin-piperaquine. It could be necessary now to compare the antimalarial use and the dynamics of COVID-19 country by country to confirm this hypothesis.


Subject(s)
Antimalarials/pharmacology , Betacoronavirus/drug effects , Virus Replication/drug effects , Animals , Cell Survival/drug effects , Chlorocebus aethiops , SARS-CoV-2 , Vero Cells
2.
Bioorg Chem ; 129: 106185, 2022 12.
Article in English | MEDLINE | ID: covidwho-2268978

ABSTRACT

The evolving SARS-CoV-2 epidemic buffets the world, and the concerted efforts are needed to explore effective drugs. Mpro is an intriguing antiviral target for interfering with viral RNA replication and transcription. In order to get potential anti-SARS-CoV-2 agents, we established an enzymatic assay using a fluorogenic substrate to screen the inhibitors of Mpro. Fortunately, Acriflavine (ACF) and Proflavine Hemisulfate (PRF) with the same acridine scaffold were picked out for their good inhibitory activity against Mpro with IC50 of 5.60 ± 0.29 µM and 2.07 ± 0.01 µM, respectively. Further evaluation of MST assay and enzymatic kinetics experiment in vitro showed that they had a certain affinity to SARS-CoV-2 Mpro and were both non-competitive inhibitors. In addition, they inhibited about 90 % HCoV-OC43 replication in BHK-21 cells at 1 µM. Both compounds showed nano-molar activities against SARS-CoV-2 virus, which were superior to GC376 for anti-HCoV-43, and equivalent to the standard molecule remdesivir. Our study demonstrated that ACF and PRF were inhibitors of Mpro, and ACF has been previously reported as a PLpro inhibitor. Taken together, ACF and PRF might be dual-targeted inhibitors to provide protection against infections of coronaviruses.


Subject(s)
Acriflavine , COVID-19 Drug Treatment , Coronavirus 3C Proteases , Cysteine Proteinase Inhibitors , Proflavine , SARS-CoV-2 , Viral Protease Inhibitors , Acriflavine/pharmacology , Proflavine/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Coronavirus 3C Proteases/antagonists & inhibitors , Cysteine Proteinase Inhibitors/pharmacology , Viral Protease Inhibitors/pharmacology , Mesocricetus , Animals , Cricetinae , Cell Line , Virus Replication/drug effects
3.
Arch Virol ; 165(9): 1935-1945, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-2236874

ABSTRACT

Plants are a rich source of new antiviral, pharmacologically active agents. The naturally occurring plant alkaloid berberine (BBR) is one of the phytochemicals with a broad range of biological activity, including anticancer, anti-inflammatory and antiviral activity. BBR targets different steps in the viral life cycle and is thus a good candidate for use in novel antiviral drugs and therapies. It has been shown that BBR reduces virus replication and targets specific interactions between the virus and its host. BBR intercalates into DNA and inhibits DNA synthesis and reverse transcriptase activity. It inhibits replication of herpes simplex virus (HSV), human cytomegalovirus (HCMV), human papillomavirus (HPV), and human immunodeficiency virus (HIV). This isoquinoline alkaloid has the ability to regulate the MEK-ERK, AMPK/mTOR, and NF-κB signaling pathways, which are necessary for viral replication. Furthermore, it has been reported that BBR supports the host immune response, thus leading to viral clearance. In this short review, we focus on the most recent studies on the antiviral properties of berberine and its derivatives, which might be promising agents to be considered in future studies in the fight against the current pandemic SARS-CoV-2, the virus that causes COVID-19.


Subject(s)
Antiviral Agents/pharmacology , Berberine/pharmacology , Viruses/drug effects , Animals , Antiviral Agents/chemistry , Berberine/chemistry , Humans , Plant Extracts/chemistry , Plant Extracts/pharmacology , Virus Diseases/virology , Virus Replication/drug effects , Viruses/genetics , Viruses/growth & development
5.
Phytomedicine ; 78: 153296, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-1267880

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has extensively and rapidly spread in the world, causing an outbreak of acute infectious pneumonia. However, no specific antiviral drugs or vaccines can be used. Phillyrin (KD-1), a representative ingredient of Forsythia suspensa, possesses anti-inflammatory, anti-oxidant, and antiviral activities. However, little is known about the antiviral abilities and mechanism of KD-1 against SARS-CoV-2 and human coronavirus 229E (HCoV-229E). PURPOSE: The study was designed to investigate the antiviral and anti-inflammatory activities of KD-1 against the novel SARS-CoV-2 and HCoV-229E and its potential effect in regulating host immune response in vitro. METHODS: The antiviral activities of KD-1 against SARS-CoV-2 and HCoV-229E were assessed in Vero E6 cells using cytopathic effect and plaque-reduction assay. Proinflammatory cytokine expression levels upon infection with SARS-CoV-2 and HCoV-229E infection in Huh-7 cells were measured by real-time quantitative PCR assays. Western blot assay was used to determine the protein expression of nuclear factor kappa B (NF-κB) p65, p-NF-κB p65, IκBα, and p-IκBα in Huh-7 cells, which are the key targets of the NF-κB pathway. RESULTS: KD-1 could significantly inhibit SARS-CoV-2 and HCoV-229E replication in vitro. KD-1 could also markedly reduce the production of proinflammatory cytokines (TNF-α, IL-6, IL-1ß, MCP-1, and IP-10) at the mRNA levels. Moreover, KD-1 could significantly reduce the protein expression of p-NF-κB p65, NF-κB p65, and p-IκBα, while increasing the expression of IκBα in Huh-7 cells. CONCLUSIONS: KD-1 could significantly inhibit virus proliferation in vitro, the up-regulated expression of proinflammatory cytokines induced by SARS-CoV-2 and HCoV-229E by regulating the activity of the NF-кB signaling pathway. Our findings indicated that KD-1 protected against virus attack and can thus be used as a novel strategy for controlling the coronavirus disease 2019.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Coronavirus 229E, Human/drug effects , Coronavirus Infections , Glucosides/pharmacology , NF-kappa B/metabolism , Pandemics , Pneumonia, Viral , Animals , COVID-19 , Chlorocebus aethiops , Coronavirus/drug effects , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Cytokines/metabolism , Forsythia/chemistry , Humans , Phytotherapy , Plant Extracts/pharmacology , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , SARS-CoV-2 , Severe Acute Respiratory Syndrome/virology , Signal Transduction/drug effects , Vero Cells , Virus Replication/drug effects
6.
Life Sci ; 255: 117831, 2020 Aug 15.
Article in English | MEDLINE | ID: covidwho-1267781

ABSTRACT

A new SARS coronavirus (SARS-CoV-2) belonging to the genus Betacoronavirus has caused a pandemic known as COVID-19. Among coronaviruses, the main protease (Mpro) is an essential drug target which, along with papain-like proteases catalyzes the processing of polyproteins translated from viral RNA and recognizes specific cleavage sites. There are no human proteases with similar cleavage specificity and therefore, inhibitors are highly likely to be nontoxic. Therefore, targeting the SARS-CoV-2 Mpro enzyme with small molecules can block viral replication. The present study is aimed at the identification of promising lead molecules for SARS-CoV-2 Mpro enzyme through virtual screening of antiviral compounds from plants. The binding affinity of selected small drug-like molecules to SARS-CoV-2 Mpro, SARS-CoV Mpro and MERS-CoV Mpro were studied using molecular docking. Bonducellpin D was identified as the best lead molecule which shows higher binding affinity (-9.28 kcal/mol) as compared to the control (-8.24 kcal/mol). The molecular binding was stabilized through four hydrogen bonds with Glu166 and Thr190 as well as hydrophobic interactions via eight residues. The SARS-CoV-2 Mpro shows identities of 96.08% and 50.65% to that of SARS-CoV Mpro and MERS-CoV Mpro respectively at the sequence level. At the structural level, the root mean square deviation (RMSD) between SARS-CoV-2 Mpro and SARS-CoV Mpro was found to be 0.517 Å and 0.817 Å between SARS-CoV-2 Mpro and MERS-CoV Mpro. Bonducellpin D exhibited broad-spectrum inhibition potential against SARS-CoV Mpro and MERS-CoV Mpro and therefore is a promising drug candidate, which needs further validations through in vitro and in vivo studies.


Subject(s)
Antiviral Agents/pharmacology , Betacoronavirus/drug effects , Betacoronavirus/enzymology , Coronavirus Infections/drug therapy , Plant Extracts/pharmacology , Pneumonia, Viral/drug therapy , Viral Nonstructural Proteins/antagonists & inhibitors , Amino Acid Sequence , Antiviral Agents/chemistry , Betacoronavirus/metabolism , Binding Sites , COVID-19 , Computer Simulation , Coronavirus 3C Proteases , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Cysteine Endopeptidases/chemistry , Cysteine Endopeptidases/metabolism , Drug Evaluation, Preclinical/methods , Humans , Molecular Docking Simulation , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/virology , Protease Inhibitors/chemistry , Protein Binding , SARS-CoV-2 , Small Molecule Libraries/pharmacology , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
7.
J Biol Chem ; 299(3): 102976, 2023 03.
Article in English | MEDLINE | ID: covidwho-2220925

ABSTRACT

Feline infectious peritonitis (FIP) is a serious viral illness in cats, caused by feline coronavirus. Once a cat develops clinical FIP, the prognosis is poor. The effective treatment strategy for coronavirus infections with immunopathological complications such as SARS-CoV-2, MERS, and FIP is focused on antiviral and immunomodulatory agents to inhibit virus replication and enhance the protective immune response. In this article we report the binding and conformational alteration of feline alphacoronavirus (FCoV) nucleocapsid protein by a novel compound K31. K31 noncompetitively inhibited the interaction between the purified nucleocapsid protein and the synthetic 5' terminus of viral genomic RNA in vitro. K31 was well tolerated by cells and inhibited FCoV replication in cell culture with a selective index of 115. A single dose of K31inhibited FCoV replication to an undetectable level in 24 h post treatment. K31 did not affect the virus entry to the host cell but inhibited the postentry steps of virus replication. The nucleocapsid protein forms ribonucleocapsid in association with the viral genomic RNA that serves as a template for transcription and replication of the viral genome. Our results show that K31 treatment disrupted the structural integrity of ribonucleocapsid in virus-infected cells. After the COVID-19 pandemic, most of the antiviral drug development strategies have focused on RdRp and proteases encoded by the viral genome. Our results have shown that nucleocapsid protein is a druggable target for anticoronavirus drug discovery.


Subject(s)
Antiviral Agents , Coronavirus, Feline , Feline Infectious Peritonitis , Nucleocapsid Proteins , Virus Replication , Animals , Cats , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Cell Culture Techniques , Coronavirus, Feline/drug effects , Coronavirus, Feline/physiology , Feline Infectious Peritonitis/drug therapy , RNA, Viral/genetics , Virus Replication/drug effects
8.
Mar Drugs ; 20(12)2022 Dec 19.
Article in English | MEDLINE | ID: covidwho-2225454

ABSTRACT

A global health concern has emerged as a response to the recent SARS-CoV-2 pandemic. The identification and inhibition of drug targets of SARS-CoV-2 is a decisive obligation of scientists. In addition to the cell entry mechanism, SARS-CoV-2 expresses a complicated replication mechanism that provides excellent drug targets. Papain-like protease (PLpro) and 3-chymotrypsin-like protease (3CLpro) play a vital role in polyprotein processing, producing functional non-structural proteins essential for viral replication and survival in the host cell. Moreover, PLpro is employed by SARS-CoV-2 for reversing host immune responses. Therefore, if some particular compound has the potential to interfere with the proteolytic activities of 3CLpro and PLpro of SARS-CoV-2, it may be effective as a treatment or prophylaxis for COVID-19, reducing viral load, and reinstating innate immune responses. Thus, the present study aims to inhibit SARS-CoV-2 through 3CLpro and PLpro using marine natural products isolated from marine algae that contain numerous beneficial biological activities. Molecular docking analysis was utilized in the present study for the initial screening of selected natural products depending on their 3CLpro and PLpro structures. Based on this approach, Ishophloroglucin A (IPA), Dieckol, Eckmaxol, and Diphlorethohydroxycarmalol (DPHC) were isolated and used to perform in vitro evaluations. IPA presented remarkable inhibitory activity against interesting drug targets. Moreover, Dieckol, Eckmaxol, and DPHC also expressed significant potential as inhibitors. Finally, the results of the present study confirm the potential of IPA, Dieckol, Eckmaxol, and DPHC as inhibitors of SARS-CoV-2. To the best of our knowledge, this is the first study that assesses the use of marine natural products as a multifactorial approach against 3CLpro and PLpro of SARS-CoV-2.


Subject(s)
Antiviral Agents , COVID-19 , Polyphenols , SARS-CoV-2 , Virus Replication , Humans , Antiviral Agents/chemistry , Antiviral Agents/isolation & purification , Antiviral Agents/pharmacology , COVID-19/prevention & control , Molecular Docking Simulation , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Virus Replication/drug effects , Polyphenols/chemistry , Polyphenols/isolation & purification , Polyphenols/pharmacology
9.
Viruses ; 14(12)2022 11 24.
Article in English | MEDLINE | ID: covidwho-2123875

ABSTRACT

SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Vaccination, supported by social and public health measures, has proven efficacious for reducing disease severity and virus spread. However, the emergence of highly transmissible viral variants that escape prior immunity highlights the need for additional mitigation approaches. Heparin binds the SARS-CoV-2 spike protein and can inhibit virus entry and replication in susceptible human cell lines and bronchial epithelial cells. Primary infection predominantly occurs via the nasal epithelium, but the nasal cell biology of SARS-CoV-2 is not well studied. We hypothesized that prophylactic intranasal administration of heparin may provide strain-agnostic protection for household contacts or those in high-risk settings against SARS-CoV-2 infection. Therefore, we investigated the ability of heparin to inhibit SARS-CoV-2 infection and replication in differentiated human nasal epithelial cells and showed that prolonged exposure to heparin inhibits virus infection. Furthermore, we establish a method for PCR detection of SARS-CoV-2 viral genomes in heparin-treated samples that can be adapted for the detection of viruses in clinical studies.


Subject(s)
Epithelial Cells , Heparin , SARS-CoV-2 , Virus Replication , Humans , COVID-19 , Epithelial Cells/virology , Heparin/pharmacology , Pandemics , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Virus Replication/drug effects
10.
Proc Natl Acad Sci U S A ; 119(30): e2123065119, 2022 07 26.
Article in English | MEDLINE | ID: covidwho-1947760

ABSTRACT

SARS-CoV-2, the causative agent of the COVID-19 pandemic, undergoes continuous evolution, highlighting an urgent need for development of novel antiviral therapies. Here we show a quantitative mass spectrometry-based succinylproteomics analysis of SARS-CoV-2 infection in Caco-2 cells, revealing dramatic reshape of succinylation on host and viral proteins. SARS-CoV-2 infection promotes succinylation of several key enzymes in the TCA, leading to inhibition of cellular metabolic pathways. We demonstrated that host protein succinylation is regulated by viral nonstructural protein (NSP14) through interaction with sirtuin 5 (SIRT5); overexpressed SIRT5 can effectively inhibit virus replication. We found succinylation inhibitors possess significant antiviral effects. We also found that SARS-CoV-2 nucleocapsid and membrane proteins underwent succinylation modification, which was conserved in SARS-CoV-2 and its variants. Collectively, our results uncover a regulatory mechanism of host protein posttranslational modification and cellular pathways mediated by SARS-CoV-2, which may become antiviral drug targets against COVID-19.


Subject(s)
Antiviral Agents , COVID-19 Drug Treatment , COVID-19 , Host-Pathogen Interactions , Molecular Targeted Therapy , Protein Processing, Post-Translational , SARS-CoV-2 , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/metabolism , COVID-19/virology , Caco-2 Cells , Exoribonucleases/metabolism , Host-Pathogen Interactions/drug effects , Humans , Protein Processing, Post-Translational/drug effects , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Sirtuins/metabolism , Succinates/metabolism , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
11.
Proc Natl Acad Sci U S A ; 119(26): e2122897119, 2022 06 28.
Article in English | MEDLINE | ID: covidwho-1890411

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolves rapidly under the pressure of host immunity, as evidenced by waves of emerging variants despite effective vaccinations, highlighting the need for complementing antivirals. We report that targeting a pyrimidine synthesis enzyme restores inflammatory response and depletes the nucleotide pool to impede SARS-CoV-2 infection. SARS-CoV-2 deploys Nsp9 to activate carbamoyl-phosphate synthetase, aspartate transcarbamoylase, and dihydroorotase (CAD) that catalyzes the rate-limiting steps of the de novo pyrimidine synthesis. Activated CAD not only fuels de novo nucleotide synthesis but also deamidates RelA. While RelA deamidation shuts down NF-κB activation and subsequent inflammatory response, it up-regulates key glycolytic enzymes to promote aerobic glycolysis that provides metabolites for de novo nucleotide synthesis. A newly synthesized small-molecule inhibitor of CAD restores antiviral inflammatory response and depletes the pyrimidine pool, thus effectively impeding SARS-CoV-2 replication. Targeting an essential cellular metabolic enzyme thus offers an antiviral strategy that would be more refractory to SARS-CoV-2 genetic changes.


Subject(s)
Antiviral Agents , Aspartate Carbamoyltransferase , COVID-19 Drug Treatment , Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) , Dihydroorotase , Enzyme Inhibitors , Pyrimidines , SARS-CoV-2 , Virus Replication , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Aspartate Carbamoyltransferase/antagonists & inhibitors , Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)/antagonists & inhibitors , Dihydroorotase/antagonists & inhibitors , Enzyme Activation/drug effects , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Humans , Inflammation/drug therapy , Mice , Pyrimidines/antagonists & inhibitors , Pyrimidines/biosynthesis , RNA-Binding Proteins/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Transcription Factor RelA/metabolism , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects
12.
Viruses ; 14(5)2022 04 28.
Article in English | MEDLINE | ID: covidwho-1820410

ABSTRACT

New strategies to rapidly develop broad-spectrum antiviral therapies are urgently required for emerging and re-emerging viruses. Host-targeting antivirals (HTAs) that target the universal host factors necessary for viral replication are the most promising approach, with broad-spectrum, foresighted function, and low resistance. We and others recently identified that host dihydroorotate dehydrogenase (DHODH) is one of the universal host factors essential for the replication of many acute-infectious viruses. DHODH is a rate-limiting enzyme catalyzing the fourth step in de novo pyrimidine synthesis. Therefore, it has also been developed as a therapeutic target for many diseases relying on cellular pyrimidine resources, such as cancers, autoimmune diseases, and viral or bacterial infections. Significantly, the successful use of DHODH inhibitors (DHODHi) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection further supports the application prospects. This review focuses on the advantages of HTAs and the antiviral effects of DHODHi with clinical applications. The multiple functions of DHODHi in inhibiting viral replication, stimulating ISGs expression, and suppressing cytokine storms make DHODHi a potent strategy against viral infection.


Subject(s)
COVID-19 Drug Treatment , Dihydroorotate Dehydrogenase , Virus Diseases , Viruses , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Dihydroorotate Dehydrogenase/antagonists & inhibitors , Humans , Pyrimidines , SARS-CoV-2/drug effects , Virus Diseases/drug therapy , Virus Replication/drug effects , Viruses/drug effects
13.
Viruses ; 14(5)2022 05 05.
Article in English | MEDLINE | ID: covidwho-1820426

ABSTRACT

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2, SARS2) remains a great global health threat and demands identification of more effective and SARS2-targeted antiviral drugs, even with successful development of anti-SARS2 vaccines. Viral replicons have proven to be a rapid, safe, and readily scalable platform for high-throughput screening, identification, and evaluation of antiviral drugs against positive-stranded RNA viruses. In the study, we report a unique robust HIV long terminal repeat (LTR)/T7 dual-promoter-driven and dual-reporter firefly luciferase (fLuc) and green fluorescent protein (GFP)-expressing SARS2 replicon. The genomic organization of the replicon was designed with quite a few features that were to ensure the replication fidelity of the replicon, to maximize the expression of the full-length replicon, and to offer the monitoring flexibility of the replicon replication. We showed the success of the construction of the replicon and expression of reporter genes fLuc and GFP and SARS structural N from the replicon DNA or the RNA that was in vitro transcribed from the replicon DNA. We also showed detection of the negative-stranded genomic RNA (gRNA) and subgenomic RNA (sgRNA) intermediates, a hallmark of replication of positive-stranded RNA viruses from the replicon. Lastly, we showed that expression of the reporter genes, N gene, gRNA, and sgRNA from the replicon was sensitive to inhibition by Remdesivir. Taken together, our results support use of the replicon for identification of anti-SARS2 drugs and development of new anti-SARS strategies targeted at the step of virus replication.


Subject(s)
Replicon , SARS-CoV-2 , Antiviral Agents/pharmacology , Genes, Reporter , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Luciferases, Firefly/genetics , Luciferases, Firefly/metabolism , Promoter Regions, Genetic , RNA, Guide, Kinetoplastida , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Virus Replication/drug effects
14.
Virology ; 571: 21-33, 2022 06.
Article in English | MEDLINE | ID: covidwho-1783830

ABSTRACT

Since December 2019, the deadly novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the current COVID-19 pandemic. To date, vaccines are available in the developed countries to prevent the infection of this virus; however, medicines are necessary to help control COVID-19. Human coronavirus 229E (HCoV-229E) causes the common cold. The main protease (Mpro) is an essential enzyme required for the multiplication of these two viruses in the host cells, and thus is an appropriate candidate to screen potential medicinal compounds. Flavonols and dihydroflavonols are two groups of plant flavonoids. In this study, we report docking simulation with two Mpro enzymes and five flavonols and three dihydroflavonols, in vitro inhibition of the SARS-CoV-2 Mpro, and in vitro inhibition of the HCoV 229E replication. The docking simulation results predicted that (+)-dihydrokaempferol, (+)- dihydroquercetin, (+)-dihydromyricetin, kaempferol, quercetin, myricentin, isoquercitrin, and rutin could bind to at least two subsites (S1, S1', S2, and S4) in the binding pocket and inhibit the activity of SARS-CoV-2 Mpro. Their affinity scores ranged from -8.8 to -7.4 (kcal/mol). Likewise, these compounds were predicted to bind and inhibit the HCoV-229E Mpro activity with affinity scores ranging from -7.1 to -7.8 (kcal/mol). In vitro inhibition assays showed that seven available compounds effectively inhibited the SARS-CoV-2 Mpro activity and their IC50 values ranged from 0.125 to 12.9 µM. Five compounds inhibited the replication of HCoV-229E in Huh-7 cells. These findings indicate that these antioxidative flavonols and dihydroflavonols are promising candidates for curbing the two viruses.


Subject(s)
Coronavirus 229E, Human , Coronavirus 3C Proteases , Flavonols , SARS-CoV-2 , COVID-19 , Coronavirus 229E, Human/drug effects , Coronavirus 229E, Human/physiology , Coronavirus 3C Proteases/antagonists & inhibitors , Flavonols/pharmacology , Humans , Molecular Docking Simulation , SARS-CoV-2/drug effects , Virus Replication/drug effects
16.
Eur J Med Chem ; 229: 114046, 2022 Feb 05.
Article in English | MEDLINE | ID: covidwho-1768050

ABSTRACT

Severe diseases such as the ongoing COVID-19 pandemic, as well as the previous SARS and MERS outbreaks, are the result of coronavirus infections and have demonstrated the urgent need for antiviral drugs to combat these deadly viruses. Due to its essential role in viral replication and function, 3CLpro (main coronaviruses cysteine-protease) has been identified as a promising target for the development of antiviral drugs. Previously reported SARS-CoV 3CLpro non-covalent inhibitors were used as a starting point for the development of covalent inhibitors of SARS-CoV-2 3CLpro. We report herein our efforts in the design and synthesis of submicromolar covalent inhibitors when the enzymatic activity of the viral protease was used as a screening platform.


Subject(s)
Antiviral Agents/chemical synthesis , Antiviral Agents/pharmacology , COVID-19 Drug Treatment , Coronavirus 3C Proteases/antagonists & inhibitors , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Animals , Drug Design , High-Throughput Screening Assays , Humans , Virus Replication/drug effects
17.
J Biol Chem ; 297(6): 101362, 2021 12.
Article in English | MEDLINE | ID: covidwho-1751075

ABSTRACT

The Nsp9 replicase is a conserved coronaviral protein that acts as an essential accessory component of the multi-subunit viral replication/transcription complex. Nsp9 is the predominant substrate for the essential nucleotidylation activity of Nsp12. Compounds specifically interfering with this viral activity would facilitate its study. Using a native mass-spectrometry-based approach to screen a natural product library for Nsp9 binders, we identified an ent-kaurane natural product, oridonin, capable of binding to purified SARS-CoV-2 Nsp9 with micromolar affinities. By determining the crystal structure of the Nsp9-oridonin complex, we showed that oridonin binds through a conserved site near Nsp9's C-terminal GxxxG-helix. In enzymatic assays, oridonin's binding to Nsp9 reduces its potential to act as substrate for Nsp12's Nidovirus RdRp-Associated Nucleotidyl transferase (NiRAN) domain. We also showed using in vitro cellular assays oridonin, while cytotoxic at higher doses has broad antiviral activity, reducing viral titer following infection with either SARS-CoV-2 or, to a lesser extent, MERS-CoV. Accordingly, these preliminary findings suggest that the oridonin molecular scaffold may have the potential to be developed into an antiviral compound to inhibit the function of Nsp9 during coronaviral replication.


Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , Diterpenes, Kaurane/pharmacology , RNA-Binding Proteins/metabolism , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/metabolism , Virus Replication/drug effects , Animals , Antiviral Agents/chemistry , Binding Sites/drug effects , Biological Products/chemistry , Biological Products/pharmacology , COVID-19/metabolism , COVID-19/virology , Chlorocebus aethiops , Diterpenes, Kaurane/chemistry , Humans , Molecular Docking Simulation , RNA-Binding Proteins/chemistry , SARS-CoV-2/chemistry , SARS-CoV-2/physiology , Vero Cells , Viral Nonstructural Proteins/chemistry
18.
Sci Rep ; 12(1): 2505, 2022 02 15.
Article in English | MEDLINE | ID: covidwho-1747189

ABSTRACT

Mpro, the main protease of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is essential for the viral life cycle. Accordingly, several groups have performed in silico screens to identify Mpro inhibitors that might be used to treat SARS-CoV-2 infections. We selected more than five hundred compounds from the top-ranking hits of two very large in silico screens for on-demand synthesis. We then examined whether these compounds could bind to Mpro and inhibit its protease activity. Two interesting chemotypes were identified, which were further evaluated by characterizing an additional five hundred synthesis on-demand analogues. The compounds of the first chemotype denatured Mpro and were considered not useful for further development. The compounds of the second chemotype bound to and enhanced the melting temperature of Mpro. The most active compound from this chemotype inhibited Mpro in vitro with an IC50 value of 1 µM and suppressed replication of the SARS-CoV-2 virus in tissue culture cells. Its mode of binding to Mpro was determined by X-ray crystallography, revealing that it is a non-covalent inhibitor. We propose that the inhibitors described here could form the basis for medicinal chemistry efforts that could lead to the development of clinically relevant inhibitors.


Subject(s)
Coronavirus 3C Proteases/antagonists & inhibitors , Protease Inhibitors/chemistry , SARS-CoV-2/enzymology , Binding Sites , COVID-19/pathology , COVID-19/virology , Coronavirus 3C Proteases/genetics , Coronavirus 3C Proteases/metabolism , Crystallography, X-Ray , Humans , Molecular Conformation , Molecular Docking Simulation , Nitriles/chemistry , Nitriles/metabolism , Nitriles/pharmacology , Protease Inhibitors/metabolism , Protease Inhibitors/pharmacology , Quinazolines/chemistry , Quinazolines/metabolism , Quinazolines/pharmacology , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Virus Replication/drug effects
19.
Front Immunol ; 13: 841459, 2022.
Article in English | MEDLINE | ID: covidwho-1731786

ABSTRACT

In late 2019, COVID-19 emerged in Wuhan, China. Currently, it is an ongoing global health threat stressing the need for therapeutic compounds. Linking the virus life cycle and its interaction with cell receptors and internal cellular machinery is key to developing therapies based on the control of infectivity and inflammation. In this framework, we evaluate the combination of cannabidiol (CBD), as an anti-inflammatory molecule, and terpenes, by their anti-microbiological properties, in reducing SARS-CoV-2 infectivity. Our group settled six formulations combining CBD and terpenes purified from Cannabis sativa L, Origanum vulgare, and Thymus mastichina. The formulations were analyzed by HPLC and GC-MS and evaluated for virucide and antiviral potential by in vitro studies in alveolar basal epithelial, colon, kidney, and keratinocyte human cell lines. Conclusions and Impact: We demonstrate the virucide effectiveness of CBD and terpene-based formulations. F2TC reduces the infectivity by 17%, 24%, and 99% for CaCo-2, HaCat, and A549, respectively, and F1TC by 43%, 37%, and 29% for Hek293T, HaCaT, and Caco-2, respectively. To the best of our knowledge, this is the first approach that tackles the combination of CBD with a specific group of terpenes against SARS-CoV-2 in different cell lines. The differential effectiveness of formulations according to the cell line can be relevant to understanding the pattern of virus infectivity and the host inflammation response, and lead to new therapeutic strategies.


Subject(s)
Antiviral Agents/pharmacology , Cannabidiol/pharmacology , SARS-CoV-2/drug effects , Terpenes/pharmacology , Anti-Inflammatory Agents/pharmacology , Antiviral Agents/chemistry , Cannabidiol/chemistry , Cell Line , Cell Survival/drug effects , Drug Synergism , Humans , Plants, Medicinal/chemistry , Terpenes/chemistry , Virus Internalization/drug effects , Virus Replication/drug effects
20.
Front Immunol ; 13: 820131, 2022.
Article in English | MEDLINE | ID: covidwho-1731776

ABSTRACT

Coronavirus disease 2019 (COVID-19) is currently a worldwide emergency caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). In observational clinical studies, statins have been identified as beneficial to hospitalized patients with COVID-19. However, experimental evidence of underlying statins protection against SARS-CoV-2 remains elusive. Here we reported for the first-time experimental evidence of the protective effects of simvastatin treatment both in vitro and in vivo. We found that treatment with simvastatin significantly reduced the viral replication and lung damage in vivo, delaying SARS-CoV-2-associated physiopathology and mortality in the K18-hACE2-transgenic mice model. Moreover, simvastatin also downregulated the inflammation triggered by SARS-CoV-2 infection in pulmonary tissue and in human neutrophils, peripheral blood monocytes, and lung epithelial Calu-3 cells in vitro, showing its potential to modulate the inflammatory response both at the site of infection and systemically. Additionally, we also observed that simvastatin affected the course of SARS-CoV-2 infection through displacing ACE2 on cell membrane lipid rafts. In conclusion, our results show that simvastatin exhibits early protective effects on SARS-CoV-2 infection by inhibiting virus cell entry and inflammatory cytokine production, through mechanisms at least in part dependent on lipid rafts disruption.


Subject(s)
COVID-19 Drug Treatment , Down-Regulation/drug effects , Inflammation/drug therapy , Membrane Microdomains/drug effects , SARS-CoV-2/pathogenicity , Simvastatin/pharmacology , Animals , COVID-19/virology , Disease Models, Animal , Humans , Inflammation/virology , Lung/virology , Mice , Mice, Transgenic , Virus Replication/drug effects
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