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1.
Biochem Soc Trans ; 51(3): 1361-1375, 2023 06 28.
Article in English | MEDLINE | ID: covidwho-20232811

ABSTRACT

Alpha-1-antitrypsin (AAT), a serine protease inhibitor (serpin), is increasingly recognized to inhibit SARS-CoV-2 infection and counter many of the pathogenic mechanisms of COVID-19. Herein, we reviewed the epidemiologic evidence, the molecular mechanisms, and the clinical evidence that support this paradigm. As background to our discussion, we first examined the basic mechanism of SARS-CoV-2 infection and contend that despite the availability of vaccines and anti-viral agents, COVID-19 remains problematic due to viral evolution. We next underscored that measures to prevent severe COVID-19 currently exists but teeters on a balance and that current treatment for severe COVID-19 remains grossly suboptimal. We then reviewed the epidemiologic and clinical evidence that AAT deficiency increases risk of COVID-19 infection and of more severe disease, and the experimental evidence that AAT inhibits cell surface transmembrane protease 2 (TMPRSS2) - a host serine protease required for SARS-CoV-2 entry into cells - and that this inhibition may be augmented by heparin. We also elaborated on the panoply of other activities of AAT (and heparin) that could mitigate severity of COVID-19. Finally, we evaluated the available clinical evidence for AAT treatment of COVID-19.


Subject(s)
COVID-19 , alpha 1-Antitrypsin Deficiency , Humans , Heparin , Molecular Epidemiology , SARS-CoV-2
3.
Front Immunol ; 13: 811430, 2022.
Article in English | MEDLINE | ID: covidwho-1731772

ABSTRACT

Despite significant research efforts, treatment options for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain limited. This is due in part to a lack of therapeutics that increase host defense to the virus. Replication of SARS-CoV-2 in lung tissue is associated with marked infiltration of macrophages and activation of innate immune inflammatory responses that amplify tissue injury. Antagonists of the androgen (AR) and glucocorticoid (GR) receptors have shown efficacy in models of COVID-19 and in clinical studies because the cell surface proteins required for viral entry, angiotensin converting enzyme 2 (ACE2) and the transmembrane protease, serine 2 (TMPRSS2), are transcriptionally regulated by these receptors. We postulated that the GR and AR modulator, PT150, would reduce infectivity of SARS-CoV-2 and prevent inflammatory lung injury in the Syrian golden hamster model of COVID-19 by down-regulating expression of critical genes regulated through these receptors. Animals were infected intranasally with 2.5 × 104 TCID50/ml equivalents of SARS-CoV-2 (strain 2019-nCoV/USA-WA1/2020) and PT150 was administered by oral gavage at 30 and 100 mg/Kg/day for a total of 7 days. Animals were examined at 3, 5 and 7 days post-infection (DPI) for lung histopathology, viral load and production of proteins regulating the progression of SARS-CoV-2 infection. Results indicated that oral administration of PT150 caused a dose-dependent decrease in replication of SARS-CoV-2 in lung, as well as in expression of ACE2 and TMPRSS2. Lung hypercellularity and infiltration of macrophages and CD4+ T-cells were dramatically decreased in PT150-treated animals, as was tissue damage and expression of IL-6. Molecular docking studies suggest that PT150 binds to the co-activator interface of the ligand-binding domain of both AR and GR, thereby acting as an allosteric modulator and transcriptional repressor of these receptors. Phylogenetic analysis of AR and GR revealed a high degree of sequence identity maintained across multiple species, including humans, suggesting that the mechanism of action and therapeutic efficacy observed in Syrian hamsters would likely be predictive of positive outcomes in patients. PT150 is therefore a strong candidate for further clinical development for the treatment of COVID-19 across variants of SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , COVID-19 Drug Treatment , Glucocorticoids/metabolism , Immunity, Innate/drug effects , Inflammation/drug therapy , Receptors, Androgen/metabolism , Virus Internalization/drug effects , Animals , COVID-19/metabolism , Disease Models, Animal , Female , Inflammation/metabolism , Inflammation/virology , Lung/virology , Male , Mesocricetus , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Viral Load/drug effects
4.
Nat Rev Microbiol ; 20(5): 299-314, 2022 05.
Article in English | MEDLINE | ID: covidwho-1526083

ABSTRACT

In the past two decades, three coronaviruses with ancestral origins in bats have emerged and caused widespread outbreaks in humans, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the first SARS epidemic in 2002-2003, the appreciation of bats as key hosts of zoonotic coronaviruses has advanced rapidly. More than 4,000 coronavirus sequences from 14 bat families have been identified, yet the true diversity of bat coronaviruses is probably much greater. Given that bats are the likely evolutionary source for several human coronaviruses, including strains that cause mild upper respiratory tract disease, their role in historic and future pandemics requires ongoing investigation. We review and integrate information on bat-coronavirus interactions at the molecular, tissue, host and population levels. We identify critical gaps in knowledge of bat coronaviruses, which relate to spillover and pandemic risk, including the pathways to zoonotic spillover, the infection dynamics within bat reservoir hosts, the role of prior adaptation in intermediate hosts for zoonotic transmission and the viral genotypes or traits that predict zoonotic capacity and pandemic potential. Filling these knowledge gaps may help prevent the next pandemic.


Subject(s)
COVID-19 , Chiroptera , Animals , Evolution, Molecular , Humans , Phylogeny , SARS-CoV-2/genetics
5.
PLoS Pathog ; 17(5): e1009585, 2021 05.
Article in English | MEDLINE | ID: covidwho-1234597

ABSTRACT

Coronavirus disease-19 (COVID-19) emerged in late 2019 in China and rapidly became pandemic. As with other coronaviruses, a preponderance of evidence suggests the virus originated in horseshoe bats (Rhinolophus spp.) and may have infected an intermediate host prior to spillover into humans. A significant concern is that SARS-CoV-2 could become established in secondary reservoir hosts outside of Asia. To assess this potential, we challenged deer mice (Peromyscus maniculatus) with SARS-CoV-2 and found robust virus replication in the upper respiratory tract, lungs and intestines, with detectable viral RNA for up to 21 days in oral swabs and 6 days in lungs. Virus entry into the brain also occurred, likely via gustatory-olfactory-trigeminal pathway with eventual compromise to the blood-brain barrier. Despite this, no conspicuous signs of disease were observed, and no deer mice succumbed to infection. Expression of several innate immune response genes were elevated in the lungs, including IFNα, IFNß, Cxcl10, Oas2, Tbk1 and Pycard. Elevated CD4 and CD8ß expression in the lungs was concomitant with Tbx21, IFNγ and IL-21 expression, suggesting a type I inflammatory immune response. Contact transmission occurred from infected to naive deer mice through two passages, showing sustained natural transmission and localization into the olfactory bulb, recapitulating human neuropathology. In the second deer mouse passage, an insertion of 4 amino acids occurred to fixation in the N-terminal domain of the spike protein that is predicted to form a solvent-accessible loop. Subsequent examination of the source virus from BEI Resources determined the mutation was present at very low levels, demonstrating potent purifying selection for the insert during in vivo passage. Collectively, this work has determined that deer mice are a suitable animal model for the study of SARS-CoV-2 respiratory disease and neuropathogenesis, and that they have the potential to serve as secondary reservoir hosts in North America.


Subject(s)
COVID-19/physiopathology , COVID-19/transmission , Peromyscus/virology , Rodent Diseases/transmission , Animals , Brain/pathology , Brain/virology , COVID-19/pathology , Disease Models, Animal , Disease Reservoirs , Disease Susceptibility , Female , Male , Rodent Diseases/pathology , Rodent Diseases/virology , Spike Glycoprotein, Coronavirus/genetics , Virus Replication
6.
Virology ; 558: 28-37, 2021 06.
Article in English | MEDLINE | ID: covidwho-1057461

ABSTRACT

To help fight COVID-19, new molecular tools specifically targeting critical components of the causative agent of COVID-19, SARS-Coronavirus-2 (SARS-CoV-2), are desperately needed. The SARS-CoV-2 nucleocapsid protein is critical for viral replication, integral to viral particle assembly, and a major diagnostic marker for infection and immune protection. Currently the limited available antibody reagents targeting the nucleocapsid protein are not specific to SARS-CoV-2 nucleocapsid protein, and sequences for these antibodies are not publicly available. In this work we developed and characterized a series of new mouse monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein, with a specific clone, mBG86, targeting only SARS-CoV-2 nucleocapsid protein. The monoclonal antibodies were validated in ELISA, Western blot, and immunofluorescence analyses. The variable regions from six select clones were cloned and sequenced, and preliminary epitope mapping of the sequenced clones was performed. Overall, these new antibody reagents will be of significant value in the fight against COVID-19.


Subject(s)
Antibodies, Monoclonal , Antibodies, Viral , COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/isolation & purification , Antibodies, Viral/immunology , Antibodies, Viral/isolation & purification , COVID-19/epidemiology , Cloning, Molecular , Escherichia coli , Female , Humans , Mice , Mice, Inbred BALB C , Phosphoproteins/immunology , Recombinant Proteins/immunology
7.
Front Immunol ; 11: 614256, 2020.
Article in English | MEDLINE | ID: covidwho-1004681

ABSTRACT

The emergence of COVID-19 has led to a pandemic that has caused millions of cases of disease, variable morbidity and hundreds of thousands of deaths. Currently, only remdesivir and dexamethasone have demonstrated limited efficacy, only slightly reducing disease burden, thus novel approaches for clinical management of COVID-19 are needed. We identified a panel of human monoclonal antibody clones from a yeast display library with specificity to the SARS-CoV-2 spike protein receptor binding domain that neutralized the virus in vitro. Administration of the lead antibody clone to Syrian hamsters challenged with SARS-CoV-2 significantly reduced viral load and histopathology score in the lungs. Moreover, the antibody interrupted monocyte infiltration into the lungs, which may have contributed to the reduction of disease severity by limiting immunopathological exacerbation. The use of this antibody could provide an important therapy for treatment of COVID-19 patients.


Subject(s)
Antibodies, Monoclonal , Antibodies, Neutralizing , Antibodies, Viral , COVID-19 Drug Treatment , COVID-19 , Immunoglobulin G , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/pharmacology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/pharmacology , Antibodies, Viral/immunology , Antibodies, Viral/pharmacology , COVID-19/blood , COVID-19/immunology , Chlorocebus aethiops , Humans , Immunoglobulin G/immunology , Immunoglobulin G/pharmacology , Male , Mesocricetus , Severity of Illness Index , Vero Cells , Viral Load/drug effects , Viral Load/immunology
8.
bioRxiv ; 2020 Sep 03.
Article in English | MEDLINE | ID: covidwho-920839

ABSTRACT

The global COVID-19 pandemic has caused massive disruptions in every society around the world. To help fight COVID-19, new molecular tools specifically targeting critical components of the causative agent of COVID-19, SARS-Coronavirus-2 (SARS-CoV-2), are desperately needed. The SARS-CoV-2 nucleocapsid protein is a major component of the viral replication processes, integral to viral particle assembly, and is a major diagnostic marker for infection and immune protection. Currently available antibody reagents targeting the nucleocapsid protein were primarily developed against the related SARS-CoV virus and are not specific to SARS-CoV-2 nucleocapsid protein. Therefore, in this work we developed and characterized a series of new mouse monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein. The anti-nucleocapsid monoclonal antibodies were tested in ELISA, western blot, and immunofluorescence analyses. The variable regions from the heavy and light chains from five select clones were cloned and sequenced, and preliminary epitope mapping of the sequenced clones was performed. Overall, the new antibody reagents described here will be of significant value in the fight against COVID-19.

9.
bioRxiv ; 2020 Aug 07.
Article in English | MEDLINE | ID: covidwho-721086

ABSTRACT

Coronavirus disease-19 (COVID-19) emerged in November, 2019 in China and rapidly became pandemic. As with other coronaviruses, a preponderance of evidence suggests the virus originated in horseshoe bats (Rhinolophus spp.) and likely underwent a recombination event in an intermediate host prior to entry into human populations. A significant concern is that SARS-CoV-2 could become established in secondary reservoir hosts outside of Asia. To assess this potential, we challenged deer mice (Peromyscus maniculatus) with SARS-CoV-2 and found robust virus replication in the upper respiratory tract, lungs and intestines, with detectable viral RNA for up to 21 days in oral swabs and 14 days in lungs. Virus entry into the brain also occurred, likely via gustatory-olfactory-trigeminal pathway with eventual compromise to the blood brain barrier. Despite this, no conspicuous signs of disease were observed and no deer mice succumbed to infection. Expression of several innate immune response genes were elevated in the lungs, notably IFNα, Cxcl10, Oas2, Tbk1 and Pycard. Elevated CD4 and CD8ß expression in the lungs was concomitant with Tbx21, IFNγ and IL-21 expression, suggesting a type I inflammatory immune response. Contact transmission occurred from infected to naive deer mice through two passages, showing sustained natural transmission. In the second deer mouse passage, an insertion of 4 amino acids occurred to fixation in the N-terminal domain of the spike protein that is predicted to form a solvent-accessible loop. Subsequent examination of the source virus from BEI Resources indicated the mutation was present at very low levels, demonstrating potent purifying selection for the insert during in vivo passage. Collectively, this work has determined that deer mice are a suitable animal model for the study of SARS-CoV-2 pathogenesis, and that they have the potential to serve as secondary reservoir hosts that could lead to periodic outbreaks of COVID-19 in North America.

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