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1.
Molecules ; 28(1):160, 2023.
Article in English | MDPI | ID: covidwho-2166745

ABSTRACT

The Coronavirus Disease 2019 (COVID-19) and dengue fever (DF) pandemics both remain to be significant public health concerns in the foreseeable future. Anti-SARS-CoV-2 drugs and vaccines are both indispensable to eliminate the epidemic situation. Here, two piperazine-based polyphenol derivatives DF-47 and DF-51 were identified as potential inhibitors directly blocking the active site of SARS-CoV-2 and DENV RdRp. Data through RdRp inhibition screening of an in-house library and in vitro antiviral study selected DF-47 and DF-51 as effective inhibitors of SARS-CoV-2/DENV polymerase. Moreover, in silico simulation revealed stable binding modes between the DF-47/DF-51 and SARS-CoV-2/DENV RdRp, respectively, including chelating with Mg2+ near polymerase active site. This work discovered the inhibitory effect of two polyphenols on distinct viral RdRp, which are expected to be developed into broad-spectrum, non-nucleoside RdRp inhibitors with new scaffold.

2.
Antiviral Research ; : 105506, 2022.
Article in English | ScienceDirect | ID: covidwho-2165061

ABSTRACT

Massive efforts on both vaccine development and antiviral research were launched to combat the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We contributed, amongst others, by the development of a high-throughput screening (HTS) antiviral assay against SARS-CoV-2 using a fully automated, high-containment robot system. Here, we describe the development of this novel, convenient and phenotypic dual-reporter virus-cell-based high-content imaging assay using the A549+hACE2+TMPRSS2_mCherry reporter lung carcinoma cell line and an ancestral SARS-CoV-2_Wuhan_mNeonGreen reporter virus. Briefly, by means of clonal selection, a host cell subclone was selected that (i) efficiently supports replication of the reporter virus with high expression, upon infection, of the NeonGreen fluorescent reporter protein, (ii) that is not affected by virus-induced cytopathogenic effects and, (iii) that expresses a strong fluorescent mCherry signal in the nucleus. The selected clone matched these criteria with an infection rate on average of 75% with limited cell death. The average (R)Z′-factors of the assay plates were all >0.8, which indicates a robust assay suitable for HTS purposes. A selection of reference compounds that inhibits SARS-CoV-2 replication in vitro were used to validate this novel dual-reporter assay and confirms the data reported in the literature. This assay is a convenient and powerful tool for HTS of large compound libraries against SARS-CoV-2.

3.
Front Chem ; 10: 1058229, 2022.
Article in English | MEDLINE | ID: covidwho-2119726

ABSTRACT

RNA viral infections, including those caused by respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and Venezuelan Equine encephalitis virus (VEEV), pose a major global health challenge. Here, we report the synthesis and screening of a series of pyrrolo[2,3-b]pyridines targeting RSV, SARS-CoV-2 and/or VEEV. From this campaign, a series of lead compounds was generated that demonstrated antiviral activity in the low single-digit micromolar range against the various viruses and did not show cytotoxicity. These findings highlight the potential of 3-alkynyl-5-aryl-7-aza-indoles as a promising chemotype for the development of broad-spectrum antiviral agents.

4.
Nat Commun ; 13(1): 6644, 2022 Nov 04.
Article in English | MEDLINE | ID: covidwho-2106406

ABSTRACT

Current COVID-19 vaccines are based on prototypic spike sequences from ancestral 2019 SARS-CoV-2 strains. However, the ongoing pandemic is fueled by variants of concern (VOC) escaping vaccine-mediated protection. Here we demonstrate how immunization in hamsters using prototypic spike expressed from yellow fever 17D (YF17D) as vector blocks ancestral virus (B lineage) and VOC Alpha (B.1.1.7) yet fails to fully protect from Beta (B.1.351). However, the same YF17D vectored vaccine candidate with an evolved antigen induced considerably improved neutralizing antibody responses against VOCs Beta, Gamma (P.1) and the recently predominant Omicron (B.1.1.529), while maintaining immunogenicity against ancestral virus and VOC Delta (B.1.617.2). Thus vaccinated animals resisted challenge by all VOCs, including vigorous high titre exposure to the most difficult to cover Beta, Delta and Omicron variants, eliminating detectable virus and markedly improving lung pathology. Finally, vaccinated hamsters did not transmit Delta variant to non-vaccinated cage mates. Overall, our data illustrate how current first-generation COVID-19 vaccines may need to be updated to maintain efficacy against emerging VOCs and their spread at community level.


Subject(s)
COVID-19 , Viral Vaccines , Yellow Fever Vaccine , Cricetinae , Animals , Humans , SARS-CoV-2/genetics , Viral Vaccines/genetics , COVID-19 Vaccines , COVID-19/prevention & control , Antibodies, Neutralizing , Antibodies, Viral , Spike Glycoprotein, Coronavirus/genetics
5.
Neuron ; 2022 Nov 10.
Article in English | MEDLINE | ID: covidwho-2105658

ABSTRACT

Can SARS-CoV-2 hitchhike on the olfactory projection and take a direct and short route from the nose into the brain? We reasoned that the neurotropic or neuroinvasive capacity of the virus, if it exists, should be most easily detectable in individuals who died in an acute phase of the infection. Here, we applied a postmortem bedside surgical procedure for the rapid procurement of tissue, blood, and cerebrospinal fluid samples from deceased COVID-19 patients infected with the Delta, Omicron BA.1, or Omicron BA.2 variants. Confocal imaging of sections stained with fluorescence RNAscope and immunohistochemistry afforded the light-microscopic visualization of extracellular SARS-CoV-2 virions in tissues. We failed to find evidence for viral invasion of the parenchyma of the olfactory bulb and the frontal lobe of the brain. Instead, we identified anatomical barriers at vulnerable interfaces, exemplified by perineurial olfactory nerve fibroblasts enwrapping olfactory axon fascicles in the lamina propria of the olfactory mucosa.

6.
Front Cardiovasc Med ; 9: 964512, 2022.
Article in English | MEDLINE | ID: covidwho-2099115

ABSTRACT

Recovered COVID-19 patients often display cardiac dysfunction, even after a mild infection. Most current histological results come from patients that are hospitalized and therefore represent more severe outcomes than most COVID-19 patients face. To overcome this limitation, we investigated the cardiac effects of SARS-CoV-2 infection in a hamster model. SARS-CoV-2 infected hamsters developed diastolic dysfunction after recovering from COVID-19. Histologically, increased cardiomyocyte size was present at the peak of viral load and remained at all time points investigated. As this increase is too rapid for hypertrophic remodeling, we found instead that the heart was oedemic. Moreover, cardiomyocyte swelling is associated with the presence of ischemia. Fibrin-rich microthrombi and pericyte loss were observed at the peak of viral load, resulting in increased HIF1α in cardiomyocytes. Surprisingly, SARS-CoV-2 infection inhibited the translocation of HIF1α to the nucleus both in hamster hearts, in cultured cardiomyocytes, as well as in an epithelial cell line. We propose that the observed diastolic dysfunction is the consequence of cardiac oedema, downstream of microvascular cardiac ischemia. Additionally, our data suggest that inhibition of HIF1α translocation could contribute to an exaggerated response upon SARS-CoV-2 infection.

7.
Science ; 378(6620): 619-627, 2022 11 11.
Article in English | MEDLINE | ID: covidwho-2078696

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages carry distinct spike mutations resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters elicit plasma-neutralizing antibodies against Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5, and that breakthrough infections, but not vaccination alone, induce neutralizing antibodies in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1, BA.2, and BA.4/5 receptor-binding domains, whereas Omicron primary infections elicit B cells of narrow specificity up to 6 months after infection. Although most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant-neutralizing antibody that is a strong candidate for clinical development.


Subject(s)
Antibodies, Neutralizing , Antibodies, Viral , Antibody Formation , COVID-19 , Immune Evasion , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Humans , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Neutralization Tests , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Immunologic Memory , Memory B Cells/immunology
8.
Mol Divers ; 2022 Oct 17.
Article in English | MEDLINE | ID: covidwho-2075500

ABSTRACT

A new series of 3-acetyl-1,3,4-oxadiazoline hybrid molecules was designed and synthesized using a condensation between acyclonucleosides and substituted phenylhydrazone. All intermediates and final products were screened against Leishmania donovani, a Protozoan parasite and against three viruses SARS-CoV-2, HCMV and VZV. While no significant activity was observed against the viruses, the intermediate with 6-azatymine as thymine and 5-azathymine-3-acetyl-1,3,4-oxadiazoline hybrid exhibited a significant antileishmanial activity. The later compound was the most promising, exhibiting an IC50 value at 8.98 µM on L. donovani intramacrophage amastigotes and a moderate selectivity index value at 2.4.

9.
J Med Chem ; 65(19): 13328-13342, 2022 10 13.
Article in English | MEDLINE | ID: covidwho-2050247

ABSTRACT

SARS-CoV-2 is the causative agent behind the COVID-19 pandemic. The main protease (Mpro, 3CLpro) of SARS-CoV-2 is a key enzyme that processes polyproteins translated from the viral RNA. Mpro is therefore an attractive target for the design of inhibitors that block viral replication. We report the diastereomeric resolution of the previously designed SARS-CoV-2 Mpro α-ketoamide inhibitor 13b. The pure (S,S,S)-diastereomer, 13b-K, displays an IC50 of 120 nM against the Mpro and EC50 values of 0.8-3.4 µM for antiviral activity in different cell types. Crystal structures have been elucidated for the Mpro complexes with each of the major diastereomers, the active (S,S,S)-13b (13b-K), and the nearly inactive (R,S,S)-13b (13b-H); results for the latter reveal a novel binding mode. Pharmacokinetic studies show good levels of 13b-K after inhalative as well as after peroral administration. The active inhibitor (13b-K) is a promising candidate for further development as an antiviral treatment for COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases , Cysteine Endopeptidases/metabolism , Humans , Pandemics , Polyproteins , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , RNA, Viral , Viral Nonstructural Proteins/metabolism
10.
EBioMedicine ; 83: 104195, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-2035960

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to the angiotensin-converting enzyme 2 (ACE2) receptor, a critical component of the kallikrein-kinin system. Its dysregulation may lead to increased vascular permeability and release of inflammatory chemokines. Interactions between the kallikrein-kinin and the coagulation system might further contribute to thromboembolic complications in COVID-19. METHODS: In this observational study, we measured plasma and tissue kallikrein hydrolytic activity, levels of kinin peptides, and myeloperoxidase (MPO)-DNA complexes as a biomarker for neutrophil extracellular traps (NETs), in bronchoalveolar lavage (BAL) fluid from patients with and without COVID-19. FINDINGS: In BAL fluid from patients with severe COVID-19 (n = 21, of which 19 were mechanically ventilated), we observed higher tissue kallikrein activity (18·2 pM [1·2-1535·0], median [range], n = 9 vs 3·8 [0·0-22·0], n = 11; p = 0·030), higher levels of the kinin peptide bradykinin-(1-5) (89·6 [0·0-2425·0], n = 21 vs 0·0 [0·0-374·0], n = 19, p = 0·001), and higher levels of MPO-DNA complexes (699·0 ng/mL [66·0-142621·0], n = 21 vs 70·5 [9·9-960·0], n = 19, p < 0·001) compared to patients without COVID-19. INTERPRETATION: Our observations support the hypothesis that dysregulation of the kallikrein-kinin system might occur in mechanically ventilated patients with severe pulmonary disease, which might help to explain the clinical presentation of patients with severe COVID-19 developing pulmonary oedema and thromboembolic complications. Therefore, targeting the kallikrein-kinin system should be further explored as a potential treatment option for patients with severe COVID-19. FUNDING: Research Foundation-Flanders (G0G4720N, 1843418N), KU Leuven COVID research fund.


Subject(s)
COVID-19 , Kallikrein-Kinin System , Angiotensin-Converting Enzyme 2 , Bradykinin , Bronchoalveolar Lavage Fluid , Humans , Kallikreins/metabolism , Peroxidase/metabolism , SARS-CoV-2 , Tissue Kallikreins/metabolism
11.
J Mol Struct ; : 134135, 2022 Sep 09.
Article in English | MEDLINE | ID: covidwho-2007964

ABSTRACT

Analogs of pyrimidine and 1,3,4-oxadiazole are two well established class of molecules proven as potent antiviral and anticancer agents in the pharmaceutical industry. We envisioned designing new molecules where these two heterocycles were conjugated with the goal of enhancing biological activity. In this vein, we synthesized a series of novel pyrimidine-1,3,4-oxadiazole conjugated hybrid molecules as potential anticancer and antiviral agents. Herein, we present a new design for 5-fluorocytosine-1,3,4-oxadiazole hybrids (5a-h) connected via a methylene bridge. An efficient synthesis of new derivatives was established, and all compounds were fully characterized by NMR and MS. Eight compounds were evaluated for their cytotoxic activity against fibrosarcoma (HT-1080), breast (MCF-7 and MDA-MB-231), lung carcinoma (A-549), and for their antiviral activity against SARS-CoV-2. Among all compounds tested, the compound 5e showed marked growth inhibition against all cell lines tested, particularly in HT-1080, with IC50 values of 19.56 µM. Meanwhile, all tested compounds showed no anti-SARS-CoV-2 activity, with EC50 >100 µM. The mechanism of cell death was investigated using Annexin V staining, caspase-3/7 activity, and analysis of cell cycle progression. The compound 5e induced apoptosis by the activation of caspase-3/7 and cell-cycle arrest in HT-1080 and A-549 cells at the G2M phase. The molecular docking suggested that the compound 5e activated caspase-3 via the formation of a stable complex protein-ligand.

12.
EBioMedicine ; 83: 104240, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-2004031

ABSTRACT

BACKGROUND: The live-attenuated yellow fever vaccine YF17D holds great promise as alternative viral vector vaccine platform, showcased by our previously presented potent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine candidate YF-S0. Besides protection from SARS-CoV-2, YF-S0 also induced strong yellow fever virus (YFV)-specific immunity, suggestive for full dual activity. A vaccine concomitantly protecting from SARS-CoV-2 and YFV would be of great benefit for those living in YFV-endemic areas with limited access to current SARS-CoV-2 vaccines. However, for broader applicability, pre-existing vector immunity should not impact the potency of such YF17D-vectored vaccines. METHODS: The immunogenicity and efficacy of YF-S0 against YFV and SARS-CoV-2 in the presence of strong pre-existing YFV immunity were evaluated in mouse and hamster challenge models. FINDINGS: Here, we show that a single dose of YF-S0 is sufficient to induce strong humoral and cellular immunity against YFV as well as SARS-CoV-2 in mice and hamsters; resulting in full protection from vigorous YFV challenge in either model; in mice against lethal intracranial YF17D challenge, and in hamsters against viscerotropic infection and liver disease following challenge with highly pathogenic hamster-adapted YFV-Asibi strain. Importantly, strong pre-existing immunity against the YF17D vector did not interfere with subsequent YF-S0 vaccination in mice or hamsters; nor with protection conferred against SARS-CoV-2 strain B1.1.7 (Alpha variant) infection in hamsters. INTERPRETATION: Our findings warrant the development of YF-S0 as dual SARS-CoV-2 and YFV vaccine. Contrary to other viral vaccine platforms, use of YF17D does not suffer from pre-existing vector immunity. FUNDING: Stated in the acknowledgments.


Subject(s)
COVID-19 , Viral Vaccines , Yellow Fever Vaccine , Yellow Fever , Animals , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Cricetinae , Humans , Mice , SARS-CoV-2 , Viral Vaccines/genetics , Yellow Fever/prevention & control , Yellow fever virus/genetics
13.
Cardiovasc Res ; 2022 Aug 23.
Article in English | MEDLINE | ID: covidwho-2001256

ABSTRACT

AIMS: SARS-CoV-2 infection causes COVID-19, which in severe cases evokes life-threatening acute respiratory distress syndrome (ARDS). Transcriptome signatures and the functional relevance of non-vascular cell types (e.g. immune and epithelial cells) in COVID-19 are becoming increasingly evident. However, despite its known contribution to vascular inflammation, recruitment/invasion of immune cells, vascular leakage and perturbed hemostasis in the lungs of severe COVID-19 patients, an in-depth interrogation of the endothelial cell (EC) compartment in lethal COVID-19 is lacking. Moreover, progressive fibrotic lung disease represents one of the complications of COVID-19 pneumonia and ARDS. Analogous features between idiopathic pulmonary fibrosis (IPF) and COVID-19 suggest partial similarities in their pathophysiology, yet, a head-to-head comparison of pulmonary cell transcriptomes between both conditions has not been implemented to date. METHODS AND RESULTS: We performed single nucleus RNA-seq (snRNA-seq) on frozen lungs from 7 deceased COVID-19 patients, 6 IPF explant lungs and 12 controls. The vascular fraction, comprising 38,794 nuclei, could be subclustered into 14 distinct EC subtypes. Non-vascular cell types, comprising 137,746 nuclei, were subclustered and used for EC-interactome analyses. Pulmonary ECs of deceased COVID-19 patients showed an enrichment of genes involved in cellular stress, as well as signatures suggestive of dampened immunomodulation and impaired vessel wall integrity. In addition, increased abundance of a population of systemic capillary and venous ECs was identified in COVID-19 and IPF. COVID-19 systemic ECs closely resembled their IPF counterparts, and a set of 30 genes was found congruently enriched in systemic ECs across studies. Receptor-ligand interaction analysis of ECs with non-vascular cell types in the pulmonary micro-environment revealed numerous previously unknown interactions specifically enriched/depleted in COVID-19 and/or IPF. CONCLUSIONS: This study uncovered novel insights into the abundance, expression patterns and interactomes of EC subtypes in COVID-19 and IPF, relevant for future investigations into the progression and treatment of both lethal conditions. TRANSLATIONAL PERSPECTIVE: While assessing clinical and molecular characteristics of severe and lethal COVID-19 cases, the vasculature's undeniable role in disease progression has been widely acknowledged. COVID-19 lung pathology moreover shares certain clinical features with late-stage IPF - yet an in-depth interrogation and direct comparison of the endothelium at single-cell level in both conditions is still lacking. By comparing the transcriptomes of ECs from lungs of deceased COVID-19 patients to those from IPF explant and control lungs, we gathered key insights the heterogeneous composition and potential roles of ECs in both lethal diseases, which may serve as a foundation for development of novel therapeutics.

14.
Sci Rep ; 12(1): 14230, 2022 08 20.
Article in English | MEDLINE | ID: covidwho-2000936

ABSTRACT

Essential oils and aromatic extracts (oleoresins, absolutes, concretes, resinoids) are often used as food flavorings and constituents of fragrance compositions. The flavor and fragrance industry observed significant growth in the sales of some natural materials during the COVID-19 outbreak. Some companies worldwide are making false claims regarding the effectiveness of their essential oils or blends (or indirectly point toward this conclusion) against coronaviruses, even though the available data on the activity of plant materials against highly pathogenic human coronaviruses are very scarce. Our exploratory study aimed to develop pioneering knowledge and provide the first experimental results on the inhibitory properties of hundreds of flavor and fragrance materials against SARS-CoV-2 main and papain-like proteases and the antiviral potential of the most active protease inhibitors. As essential oils are volatile products, they could provide an interesting therapeutic strategy for subsidiary inhalation in the long term.


Subject(s)
COVID-19 , Oils, Volatile , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Humans , Oils, Volatile/pharmacology , Protease Inhibitors , SARS-CoV-2
15.
Microorganisms ; 10(8)2022 Aug 12.
Article in English | MEDLINE | ID: covidwho-1987897

ABSTRACT

In the absence of drugs to treat or prevent COVID-19, drug repurposing can be a valuable strategy. Despite a substantial number of clinical trials, drug repurposing did not deliver on its promise. While success was observed with some repurposed drugs (e.g., remdesivir, dexamethasone, tocilizumab, baricitinib), others failed to show clinical efficacy. One reason is the lack of clear translational processes based on adequate preclinical profiling before clinical evaluation. Combined with limitations of existing in vitro and in vivo models, there is a need for a systematic approach to urgent antiviral drug development in the context of a global pandemic. We implemented a methodology to test repurposed and experimental drugs to generate robust preclinical evidence for further clinical development. This translational drug development platform comprises in vitro, ex vivo, and in vivo models of SARS-CoV-2, along with pharmacokinetic modeling and simulation approaches to evaluate exposure levels in plasma and target organs. Here, we provide examples of identified repurposed antiviral drugs tested within our multidisciplinary collaboration to highlight lessons learned in urgent antiviral drug development during the COVID-19 pandemic. Our data confirm the importance of assessing in vitro and in vivo potency in multiple assays to boost the translatability of pre-clinical data. The value of pharmacokinetic modeling and simulations for compound prioritization is also discussed. We advocate the need for a standardized translational drug development platform for mild-to-moderate COVID-19 to generate preclinical evidence in support of clinical trials. We propose clear prerequisites for progression of drug candidates for repurposing into clinical trials. Further research is needed to gain a deeper understanding of the scope and limitations of the presented translational drug development platform.

16.
J Virol ; 96(16): e0075822, 2022 08 24.
Article in English | MEDLINE | ID: covidwho-1973792

ABSTRACT

Ancestral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lacks the intrinsic ability to bind to the mouse ACE2 receptor, and therefore establishment of SARS-CoV-2 mouse models has been limited to the use of mouse-adapted viruses or genetically modified mice. Interestingly, some of the variants of concern, such as the Beta B.1.351 variant, show an improved binding to the mouse receptor and hence better replication in different wild-type (WT) mouse species. Here, we describe the establishment of a SARS-CoV-2 Beta B.1.351 variant infection model in male SCID mice as a tool to assess the antiviral efficacy of potential SARS-CoV-2 small-molecule inhibitors. Intranasal infection of male SCID mice with 105 50% tissue culture infective doses (TCID50) of the Beta B.1.351 variant resulted in high viral loads in the lungs and moderate signs of lung pathology on day 3 postinfection. Treatment of infected mice with the antiviral drugs molnupiravir (200 mg/kg, twice a day [BID]) or nirmatrelvir (300 mg/kg, BID) for 3 consecutive days significantly reduced the infectious virus titers in the lungs by 2 and 3.9 log10 TCID50/mg of tissue, respectively, and significantly improved lung pathology. Together, these data demonstrate the validity of this SCID mouse Beta B.1.351 variant infection model as a convenient preclinical model for assessment of potential activity of antivirals against SARS-CoV-2. IMPORTANCE Unlike the ancestral SARS-CoV-2 strain, the Beta (B.1.351) variant of concern has been reported to replicate to some extent in WT mice (C57BL/6 and BALB/c). We demonstrate here that infection of SCID mice with the Beta variant resulted in high viral loads in the lungs on day 3 postinfection. Treatment of infected mice with molnupiravir or nirmatrelvir for 3 consecutive days markedly reduced the infectious virus titers in the lungs and improved lung pathology. The SARS-CoV2 SCID mouse infection model, which is ideally suited for antiviral studies, offers an advantage in comparison to other SARS-CoV2 mouse models, in that there is no need for the use of mouse-adapted virus strains or genetically modified mice. Mouse models also have advantages over hamster models because (i) lower amounts of test drugs are needed, (ii) more animals can be housed in a cage, and (iii) reagents to analyze mouse samples are more readily available than those for hamsters.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Cricetinae , Disease Models, Animal , Humans , Lung , Male , Mice , Mice, Inbred C57BL , Mice, SCID , RNA, Viral
17.
Int J Mol Sci ; 23(14)2022 Jul 11.
Article in English | MEDLINE | ID: covidwho-1964002

ABSTRACT

Chikungunya virus (CHIKV) has repeatedly spread via the bite of an infected mosquito and affected more than 100 countries. The disease poses threats to public health and the economy in the infected locations. Many efforts have been devoted to identifying compounds that could inhibit CHIKV. Unfortunately, successful clinical candidates have not been found yet. Computations through the simulating recognition process were performed on complexation of the nsP3 protein of CHIKV with the structures of triply conjugated drug lead candidates. The outcomes provided the aid on rational design of functionalized quinazoline-(α-substituted coumarin)-arylsulfonate compounds to inhibit CHIKV in Vero cells. The molecular docking studies showed a void space around the ß carbon atom of coumarin when a substituent was attached at the α position. The formed vacancy offered a good chance for a Michael addition to take place owing to steric and electronic effects. The best conjugate containing a quinazolinone moiety exhibited potency with EC50 = 6.46 µM, low toxicity with CC50 = 59.7 µM, and the selective index (SI) = 9.24. Furthermore, the corresponding 4-anilinoquinazoline derivative improved the anti-CHIKV potency to EC50 = 3.84 µM, CC50 = 72.3 µM, and SI = 18.8. The conjugate with 4-anilinoquinazoline exhibited stronger binding affinity towards the macro domain than that with quinazolinone via hydrophobic and hydrogen bond interactions.


Subject(s)
Chikungunya virus , Animals , Antiviral Agents/chemistry , Arylsulfonates/metabolism , Arylsulfonates/pharmacology , Chlorocebus aethiops , Computer-Aided Design , Coumarins/pharmacology , Molecular Docking Simulation , Quinazolines/metabolism , Quinazolines/pharmacology , Quinazolinones/pharmacology , Vero Cells , Virus Replication
18.
Nat Microbiol ; 7(9): 1376-1389, 2022 09.
Article in English | MEDLINE | ID: covidwho-1960379

ABSTRACT

The SARS-CoV-2 Omicron variant has very high levels of transmission, is resistant to neutralization by authorized therapeutic human monoclonal antibodies (mAb) and is less sensitive to vaccine-mediated immunity. To provide additional therapies against Omicron, we isolated a mAb named P2G3 from a previously infected vaccinated donor and showed that it has picomolar-range neutralizing activity against Omicron BA.1, BA.1.1, BA.2 and all other variants tested. We solved the structure of P2G3 Fab in complex with the Omicron spike using cryo-electron microscopy at 3.04 Å resolution to identify the P2G3 epitope as a Class 3 mAb that is different from mAb-binding spike epitopes reported previously. Using a SARS-CoV-2 Omicron monkey challenge model, we show that P2G3 alone, or in combination with P5C3 (a broadly active Class 1 mAb previously identified), confers complete prophylactic or therapeutic protection. Although we could select for SARS-CoV-2 mutants escaping neutralization by P2G3 or by P5C3 in vitro, they had low infectivity and 'escape' mutations are extremely rare in public sequence databases. We conclude that this combination of mAbs has potential as an anti-Omicron drug.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Monoclonal , Antibodies, Viral , Cryoelectron Microscopy , Epitopes , Haplorhini , Humans , Membrane Glycoproteins , Neutralization Tests , Spike Glycoprotein, Coronavirus , Viral Envelope Proteins
19.
Science ; 377(6607): 735-742, 2022 08 12.
Article in English | MEDLINE | ID: covidwho-1949931

ABSTRACT

The coronavirus spike glycoprotein attaches to host receptors and mediates viral fusion. Using a broad screening approach, we isolated seven monoclonal antibodies (mAbs) that bind to all human-infecting coronavirus spike proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune donors. These mAbs recognize the fusion peptide and acquire affinity and breadth through somatic mutations. Despite targeting a conserved motif, only some mAbs show broad neutralizing activity in vitro against alpha- and betacoronaviruses, including animal coronaviruses WIV-1 and PDF-2180. Two selected mAbs also neutralize Omicron BA.1 and BA.2 authentic viruses and reduce viral burden and pathology in vivo. Structural and functional analyses showed that the fusion peptide-specific mAbs bound with different modalities to a cryptic epitope hidden in prefusion stabilized spike, which became exposed upon binding of angiotensin-converting enzyme 2 (ACE2) or ACE2-mimicking mAbs.


Subject(s)
Angiotensin-Converting Enzyme 2 , Antibodies, Monoclonal , Antibodies, Viral , Broadly Neutralizing Antibodies , COVID-19 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Angiotensin-Converting Enzyme 2/chemistry , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/isolation & purification , Antibodies, Viral/immunology , Antibodies, Viral/isolation & purification , Broadly Neutralizing Antibodies/immunology , COVID-19/immunology , Humans , Peptides/immunology , Protein Binding , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology
20.
ACS Med Chem Lett ; 13(5): 855-864, 2022 May 12.
Article in English | MEDLINE | ID: covidwho-1947205

ABSTRACT

A selection of compounds from a proprietary library, based on chemical diversity and various biological activities, was evaluated as potential inhibitors of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a phenotypic-based screening assay. A compound based on a 2-phenylquinoline scaffold emerged as the most promising hit, with EC50 and CC50 values of 6 and 18 µM, respectively. The subsequent selection of additional analogues, along with the synthesis of ad hoc derivatives, led to compounds that maintained low µM activity as inhibitors of SARS-CoV-2 replication and lacked cytotoxicity at 100 µM. In addition, the most promising congeners also show pronounced antiviral activity against the human coronaviruses HCoV-229E and HCoV-OC43, with EC50 values ranging from 0.2 to 9.4 µM. The presence of a 6,7-dimethoxytetrahydroisoquinoline group at the C-4 position of the 2-phenylquinoline core gave compound 6g that showed potent activity against SARS-CoV-2 helicase (nsp13), a highly conserved enzyme, highlighting a potentiality against emerging HCoVs outbreaks.

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