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1.
Signal Transduct Target Ther ; 7(1): 26, 2022 01 27.
Article in English | MEDLINE | ID: covidwho-1655545

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the causative agent of the pandemic disease COVID-19, which is so far without efficacious treatment. The discovery of therapy reagents for treating COVID-19 are urgently needed, and the structures of the potential drug-target proteins in the viral life cycle are particularly important. SARS-CoV-2, a member of the Orthocoronavirinae subfamily containing the largest RNA genome, encodes 29 proteins including nonstructural, structural and accessory proteins which are involved in viral adsorption, entry and uncoating, nucleic acid replication and transcription, assembly and release, etc. These proteins individually act as a partner of the replication machinery or involved in forming the complexes with host cellular factors to participate in the essential physiological activities. This review summarizes the representative structures and typically potential therapy agents that target SARS-CoV-2 or some critical proteins for viral pathogenesis, providing insights into the mechanisms underlying viral infection, prevention of infection, and treatment. Indeed, these studies open the door for COVID therapies, leading to ways to prevent and treat COVID-19, especially, treatment of the disease caused by the viral variants are imperative.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Drug Design/trends , Drug Repositioning , SARS-CoV-2/drug effects , Adrenal Cortex Hormones/chemistry , Adrenal Cortex Hormones/therapeutic use , Antibodies, Viral/chemistry , Antibodies, Viral/therapeutic use , Antiviral Agents/chemistry , Aptamers, Nucleotide/chemistry , Aptamers, Nucleotide/therapeutic use , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/therapeutic use , Humans , Models, Molecular , Nucleosides/chemistry , Nucleosides/therapeutic use , Protein Conformation , SARS-CoV-2/genetics , SARS-CoV-2/growth & development , SARS-CoV-2/metabolism , Virus Internalization/drug effects , Virus Release/drug effects , Virus Replication/drug effects
2.
Life Sci Alliance ; 5(4)2022 04.
Article in English | MEDLINE | ID: covidwho-1614505

ABSTRACT

The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The positive-sense single-stranded RNA virus contains a single linear RNA segment that serves as a template for transcription and replication, leading to the synthesis of positive and negative-stranded viral RNA (vRNA) in infected cells. Tools to visualize vRNA directly in infected cells are critical to analyze the viral replication cycle, screen for therapeutic molecules, or study infections in human tissue. Here, we report the design, validation, and initial application of FISH probes to visualize positive or negative RNA of SARS-CoV-2 (CoronaFISH). We demonstrate sensitive visualization of vRNA in African green monkey and several human cell lines, in patient samples and human tissue. We further demonstrate the adaptation of CoronaFISH probes to electron microscopy. We provide all required oligonucleotide sequences, source code to design the probes, and a detailed protocol. We hope that CoronaFISH will complement existing techniques for research on SARS-CoV-2 biology and COVID-19 pathophysiology, drug screening, and diagnostics.


Subject(s)
COVID-19/diagnosis , In Situ Hybridization, Fluorescence/methods , RNA, Viral/genetics , SARS-CoV-2/genetics , Virus Replication/genetics , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/pharmacology , Alanine/analogs & derivatives , Alanine/pharmacology , Animals , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , Caco-2 Cells , Cell Line, Tumor , Chlorocebus aethiops , Humans , In Situ Hybridization/methods , Microscopy, Electron/methods , RNA, Viral/ultrastructure , Reproducibility of Results , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Sensitivity and Specificity , Vero Cells , Virus Release/drug effects , Virus Release/genetics , Virus Release/physiology , Virus Replication/drug effects , Virus Replication/physiology
3.
Microbiol Spectr ; 10(1): e0150421, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1604818

ABSTRACT

In December 2019, a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started spreading worldwide causing the coronavirus disease 2019 (COVID-19) pandemic. The hyperactivation of the immune system has been proposed to account for disease severity and death in COVID-19 patients. Despite several approaches having been tested, no therapeutic protocol has been approved. Given that Cyclosporine A (CsA) is well-known to exert a strong antiviral activity on several viral strains and an anti-inflammatory role in different organs with relevant benefits in diverse pathological contexts, we tested its effects on SARS-CoV-2 infection of lung cells. We found that treatment with CsA either before or after infection of CaLu3 cells by three SARS-CoV-2 variants: (i) reduces the expression of both viral RNA and proteins in infected cells; (ii) decreases the number of progeny virions released by infected cells; (iii) dampens the virus-triggered synthesis of cytokines (including IL-6, IL-8, IL1α and TNF-α) that are involved in cytokine storm in patients. Altogether, these data provide a rationale for CsA repositioning for the treatment of severe COVID-19 patients. IMPORTANCE SARS-CoV-2 is the most recently identified member of the betacoronavirus genus responsible for the COVID-19 pandemic. Repurposing of available drugs has been a "quick and dirty" approach to try to reduce mortality and severe symptoms in affected patients initially, and can still represent an undeniable and valuable approach to face COVID-19 as the continuous appearance and rapid diffusion of more "aggressive"/transmissible variants, capable of eluding antibody neutralization, challenges the effectiveness of some anti-SARS-CoV-2 vaccines. Here, we tested a known antiviral and anti-inflammatory drug, Cyclosporine A (CsA), and found that it dampens viral infection and cytokine release from lung cells upon exposure to three different SARS-CoV-2 variants. Knock down of the main intracellular target of CsA, Cyclophilin A, does not phenocopy the drug inhibition of viral infection. Altogether, these findings shed new light on the cellular mechanisms of SARS-CoV-2 infection and provide the rationale for CsA repositioning to treat severe COVID-19 patients.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Antiviral Agents/pharmacology , COVID-19/virology , Cyclosporine/pharmacology , Cytokines/immunology , Lung/virology , SARS-CoV-2/drug effects , Virus Release/drug effects , COVID-19/genetics , COVID-19/immunology , Cytokine Release Syndrome , Cytokines/genetics , Humans , SARS-CoV-2/genetics , SARS-CoV-2/physiology
4.
Viruses ; 13(12)2021 11 23.
Article in English | MEDLINE | ID: covidwho-1542792

ABSTRACT

The ongoing coronavirus disease (COVID-19) pandemic has required a variety of non-medical interventions to limit the transmission of the causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). One such option is over-the-counter nasal sprays that aim to block virus entry and transmission within the nasal cavity. In this study, we assessed the ability of three hydroxypropyl methylcellulose (HPMC)-based powder nasal sprays, produced by Nasaleze, to inhibit SARS-CoV-2 infection and release in vitro. Upon application, the HPMC powder forms a gel-like matrix within the nasal cavity-a process we recapitulated in cell culture. We found that virus release from cells previously infected with SARS-CoV-2 was inhibited by the gel matrix product in a dose-dependent manner, with virus levels reduced by >99.99% over a 72 h period at a dose of 6.4 mg/3.5 cm2. We also show that the pre-treatment of cells with product inhibited SARS-CoV-2 infection, independent of the virus variant. The primary mechanism of action appears to be via the formation of a physical, passive barrier. However, the addition of wild garlic provided additional direct antiviral properties in some formulations. We conclude that HPMC-based nasal sprays may offer an additional component to strategies to limit the spread of respiratory viruses, including SARS-CoV-2.


Subject(s)
COVID-19/prevention & control , Hypromellose Derivatives/pharmacology , SARS-CoV-2/drug effects , Animals , Chlorocebus aethiops , Dose-Response Relationship, Drug , Nasal Sprays , Vero Cells , Virus Internalization/drug effects , Virus Release/drug effects
5.
Microbiol Spectr ; 9(1): e0043921, 2021 09 03.
Article in English | MEDLINE | ID: covidwho-1329042

ABSTRACT

Hepatitis C virus (HCV) can cause acute and chronic infection that is associated with considerable liver-related morbidity and mortality. In recent years, there has been a shift in the treatment paradigm with the discovery and approval of agents that target specific proteins vital for viral replication. We employed a cell culture-adapted strain of HCV and human hepatoma-derived cells lines to test the effects of our novel small-molecule compound (AO13) on HCV. Virus inhibition was tested by analyzing RNA replication, protein expression, and virus production in virus-infected cells treated with AO13. Treatment with AO13 inhibited virus spread in cell culture and showed a 100-fold reduction in the levels of infectious virus production. AO13 significantly reduced the level of viral RNA contained within cell culture fluids and reduced the cellular levels of HCV core protein, suggesting that the compound might act on a late step in the viral life cycle. Finally, we observed that AO13 did not affect the release of infectious virus from infected cells. Docking studies and molecular dynamics analyses suggested that AO13 might target the NS5B RNA polymerase, however, real-time RT-PCR analyses of cellular levels of HCV RNA showed only an ∼2-fold reduction in viral RNA levels in the presence of AO13. Taken together, this study revealed that AO13 showed consistent, but low-level antiviral effect against HCV, although the mechanism of action remains unclear. IMPORTANCE The discovery of curative antiviral drugs for a chronic disease such as HCV infection has encouraged drug discovery in the context of other viruses for which no curative drugs currently exist. Since we currently face a novel virus that has caused a pandemic, the need for new antiviral agents is more apparent than ever. We describe here a novel compound that shows a modest antiviral effect against HCV that could serve as a lead compound for future drug development against other important viruses such as SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Cell Culture Techniques , Hepacivirus/drug effects , Virus Replication/drug effects , Antiviral Agents/therapeutic use , Carcinoma, Hepatocellular , Cell Line , Hepacivirus/genetics , Hepacivirus/physiology , Hepatitis C/drug therapy , Hepatitis C/virology , Humans , Life Cycle Stages , Liver , Liver Neoplasms , Molecular Docking Simulation , RNA, Viral , SARS-CoV-2 , Viral Nonstructural Proteins , Virus Release/drug effects
6.
Viruses ; 13(5)2021 04 30.
Article in English | MEDLINE | ID: covidwho-1217120

ABSTRACT

Repurposing clinically available drugs to treat the new coronavirus disease 2019 (COVID-19) is an urgent need in the course of the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV-2) pandemic, as very few treatment options are available. The iminosugar Miglustat is a well-characterized drug for the treatment of rare genetic lysosome storage diseases, such as Gaucher and Niemann-Pick type C, and has also been described to be active against a variety of enveloped viruses. The activity of Miglustat is here demonstrated in the micromolar range for SARS-CoV-2 in vitro. The drug acts at the post-entry level and leads to a marked decrease of viral proteins and release of infectious viruses. The mechanism resides in the inhibitory activity toward α-glucosidases that are involved in the early stages of glycoprotein N-linked oligosaccharide processing in the endoplasmic reticulum, leading to a marked decrease of the viral Spike protein. Indeed, the antiviral potential of protein glycosylation inhibitors against SARS-CoV-2 is further highlighted by the low-micromolar activity of the investigational drug Celgosivir. These data point to a relevant role of this approach for the treatment of COVID-19.


Subject(s)
1-Deoxynojirimycin/analogs & derivatives , Antiviral Agents/pharmacology , Drug Repositioning , Glycoside Hydrolase Inhibitors/pharmacology , Indolizines/pharmacology , SARS-CoV-2/drug effects , 1-Deoxynojirimycin/pharmacology , A549 Cells , Animals , COVID-19/drug therapy , Chlorocebus aethiops , Glycosylation/drug effects , HEK293 Cells , Humans , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Release/drug effects
7.
J Med Chem ; 63(24): 15371-15388, 2020 12 24.
Article in English | MEDLINE | ID: covidwho-929526

ABSTRACT

Fatal infectious diseases caused by HIV-1, influenza A virus, Ebola virus, and currently pandemic coronavirus highlight the great need for the discovery of antiviral agents in mechanisms different from current viral replication-targeted approaches. Given the critical role of virus-host interactions in the viral life cycle, the development of entry or shedding inhibitors may expand the current repertoire of antiviral agents; the combination of antireplication inhibitors and entry or shedding inhibitors would create a multifaceted drug cocktail with a tandem antiviral mechanism. Therefore, we provide critical information about triterpenoids as potential antiviral agents targeting entry and release, focusing specifically on the emerging aspect of triterpenoid-mediated inhibition of a variety of virus-host membrane fusion mechanisms via a trimer-of-hairpin motif. These properties of triterpenoids supply their host an evolutionary advantage for chemical defense and may protect against an increasingly diverse array of viruses infecting mammals, providing a direction for antiviral drug discovery.


Subject(s)
Antiviral Agents/therapeutic use , RNA Viruses/drug effects , Triterpenes/therapeutic use , Virus Internalization/drug effects , Virus Release/drug effects , Animals , Cell Line, Tumor , Humans , Molecular Structure , SARS-CoV-2/drug effects , Structure-Activity Relationship , Virus Shedding/drug effects
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