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1.
Comput Struct Biotechnol J ; 20: 3533-3544, 2022.
Article in English | MEDLINE | ID: covidwho-1906929

ABSTRACT

Both novel and conventional vaccination strategies have been implemented worldwide since the onset of coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite various medical advances in the treatment and prevention of the spread of this contagious disease, it remains a major public health threat with a high mortality rate. As several lethal SARS-CoV-2 variants continue to emerge, the development of several vaccines and medicines, each with certain advantages and disadvantages, is underway. Additionally, many modalities are at various stages of research and development or clinical trials. Here, we summarize emerging SARS-CoV-2 variants, including delta, omicron, and "stealth omicron," as well as available oral drugs for COVID-19. We also discuss possible antigen candidates other than the receptor-binding domain protein for the development of a universal COVID-19 vaccine. The present review will serve as a helpful resource for future vaccine and drug development to combat COVID-19.

2.
Drug Discov Today ; 27(7): 1895-1912, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1850938

ABSTRACT

Cyclophilin A (CypA) is linked to diverse human diseases including viral infections. With the worldwide emergence of severe acute respiratory coronavirus 2 (SARS-CoV-2), drug repurposing has been highlighted as a strategy with the potential to speed up antiviral development. Because CypA acts as a proviral component in hepatitis C virus, coronavirus and HIV, its inhibitors have been suggested as potential treatments for these infections. Here, we review the structure of cyclosporin A and sanglifehrin A analogs as well as synthetic micromolecules inhibiting CypA; and we discuss their broad-spectrum antiviral efficacy in the context of the virus lifecycle.


Subject(s)
Antiviral Agents , COVID-19 , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , Cyclophilin A/pharmacology , Drug Repositioning , Humans , SARS-CoV-2 , Virus Replication
3.
Biomaterials ; 283: 121460, 2022 04.
Article in English | MEDLINE | ID: covidwho-1729556

ABSTRACT

The palatine tonsils (hereinafter referred to as "tonsils") serve as a reservoir for viral infections and play roles in the immune system's first line of defense. The aims of this study were to establish tonsil epithelial cell-derived organoids and examine their feasibility as an ex vivo model for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The tonsil organoids successfully recapitulated the key characteristics of the tonsil epithelium, including cellular composition, histologic properties, and biomarker distribution. Notably, the basal layer cells of the organoids express molecules essential for SARS-CoV-2 entry, such as angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin, being susceptible to the viral infection. Changes in the gene expression profile in tonsil organoids revealed that 395 genes associated with oncostatin M signaling and lipid metabolism were highly upregulated within 72 h after SARS-CoV-2 infection. Notably, remdesivir suppressed the viral RNA copy number in organoid culture supernatants and intracellular viral protein levels in a dose-dependent manner. Here, we suggest that tonsil epithelial organoids could provide a preclinical and translational research platform for investigating SARS-CoV-2 infectivity and transmissibility or for evaluating antiviral candidates.


Subject(s)
COVID-19 , Organoids , Humans , Palatine Tonsil , SARS-CoV-2 , Virus Internalization
4.
Sci Rep ; 11(1): 821, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-1065936

ABSTRACT

Influenza virus and coronavirus, belonging to enveloped RNA viruses, are major causes of human respiratory diseases. The aim of this study was to investigate the broad spectrum antiviral activity of a naturally existing sulfated polysaccharide, lambda-carrageenan (λ-CGN), purified from marine red algae. Cell culture-based assays revealed that the macromolecule efficiently inhibited both influenza A and B viruses with EC50 values ranging from 0.3 to 1.4 µg/ml, as well as currently circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with an EC50 value of 0.9 ± 1.1 µg/ml. No toxicity to the host cells was observed at concentrations up to 300 µg/ml. Plaque titration and western blot analysis verified that λ-CGN reduced expression of viral proteins in cell lysates and suppressed progeny virus production in culture supernatants in a dose-dependent manner. This polyanionic compound exerts antiviral activity by targeting viral attachment to cell surface receptors and preventing virus entry. Moreover, its intranasal administration to mice during influenza A viral challenge not only alleviated infection-mediated reductions in body weight but also protected 60% of mice from virus-induced mortality. Thus, λ-CGN could be a promising antiviral agent for preventing infection with several respiratory viruses.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Carrageenan/pharmacology , Orthomyxoviridae Infections/drug therapy , Orthomyxoviridae/drug effects , SARS-CoV-2/drug effects , Animals , Antiviral Agents/therapeutic use , Carrageenan/therapeutic use , Dogs , Female , HEK293 Cells , Humans , Madin Darby Canine Kidney Cells , Mice , Mice, Inbred BALB C , Orthomyxoviridae/physiology , SARS-CoV-2/physiology , Virus Replication/drug effects
5.
Int J Mol Sci ; 22(4)2021 Feb 04.
Article in English | MEDLINE | ID: covidwho-1063411

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. The virus still spreads globally through human-to-human transmission. Nevertheless, there are no specific treatments clinically approved. This study aimed to compare antiviral activity of gemcitabine and its analogue 2'-fluoro-2'-deoxycytidine (2FdC) against SARS-CoV-2 as well as cytotoxicity in vitro. Fluorescent image-based antiviral assays revealed that gemcitabine was highly potent, with a 50% effective concentration (EC50) of 1.2 µM, more active than the well-known nucleoside monophosphate remdesivir (EC50 = 35.4 µM). In contrast, 2FdC was marginally active (EC50 = 175.2 µM). For all three compounds, the 50% cytotoxic concentration (CC50) values were over 300 µM toward Vero CCL-81 cells. Western blot and quantitative reverse-transcription polymerase chain reaction analyses verified that gemcitabine blocked viral protein expression in virus-infected cells, not only Vero CCL-81 cells but also Calu-3 human lung epithelial cells in a dose-dependent manner. It was found that gemcitabine has a synergistic effect when combined with remdesivir. This report suggests that the difluoro group of gemcitabine is critical for the antiviral activity and that its combination with other evaluated antiviral drugs, such as remdesivir, could be a desirable option to treat SARS-CoV-2 infection.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19/drug therapy , Deoxycytidine/analogs & derivatives , SARS-CoV-2/drug effects , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Animals , Antiviral Agents/pharmacology , COVID-19/metabolism , COVID-19/virology , Cell Line , Chlorocebus aethiops , Deoxycytidine/pharmacology , Drug Therapy, Combination , Humans , Inhibitory Concentration 50 , SARS-CoV-2/physiology , Vero Cells , Virus Replication/drug effects
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