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1.
J Virol ; 95(24): e0139921, 2021 11 23.
Article in English | MEDLINE | ID: covidwho-1691426

ABSTRACT

Targeting host factors is a promising strategy to develop broad-spectrum antiviral drugs. Drugs targeting anti-apoptotic Bcl-2 family proteins that were originally developed as tumor suppressors have been reported to inhibit multiplication of different types of viruses. However, the mechanisms whereby Bcl-2 inhibitors exert their antiviral activity remain poorly understood. In this study, we have investigated the mechanisms by which obatoclax (OLX) and ABT-737 Bcl-2 inhibitors exhibited a potent antiviral activity against the mammarenavirus lymphocytic choriomeningitis virus (LCMV). OLX and ABT-737 potent anti-LCMV activity was not associated with their proapoptotic properties but rather with their ability to induce cell arrest at the G0/G1 phase. OLX- and ABT-737-mediated inhibition of Bcl-2 correlated with reduced expression levels of thymidine kinase 1 (TK1), cyclin A2 (CCNA2), and cyclin B1 (CCNB1) cell cycle regulators. In addition, small interfering RNA (siRNA)-mediated knockdown of TK1, CCNA2, and CCNB1 resulted in reduced levels of LCMV multiplication. The antiviral activity exerted by Bcl-2 inhibitors correlated with reduced levels of viral RNA synthesis at early times of infection. Importantly, ABT-737 exhibited moderate efficacy in a mouse model of LCMV infection, and Bcl-2 inhibitors displayed broad-spectrum antiviral activities against different mammarenaviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results suggest that Bcl-2 inhibitors, actively being explored as anticancer therapeutics, might be repositioned as broad-spectrum antivirals. IMPORTANCE Antiapoptotic Bcl-2 inhibitors have been shown to exert potent antiviral activities against various types of viruses via mechanisms that are currently poorly understood. This study has revealed that Bcl-2 inhibitors' mediation of cell cycle arrest at the G0/G1 phase, rather than their proapoptotic activity, plays a critical role in blocking mammarenavirus multiplication in cultured cells. In addition, we show that Bcl-2 inhibitor ABT-737 exhibited moderate antimammarenavirus activity in vivo and that Bcl-2 inhibitors displayed broad-spectrum antiviral activities against different mammarenaviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results suggest that Bcl-2 inhibitors, actively being explored as anticancer therapeutics, might be repositioned as broad-spectrum antivirals.


Subject(s)
Apoptosis , Arenaviridae/drug effects , COVID-19/drug therapy , Proto-Oncogene Proteins c-bcl-2/metabolism , A549 Cells , Animals , Antiviral Agents/pharmacology , Apoptosis Regulatory Proteins/pharmacology , Biphenyl Compounds/pharmacology , COVID-19/virology , Cell Cycle , Cell Cycle Checkpoints/drug effects , Cells, Cultured/drug effects , Cells, Cultured/virology , Chlorocebus aethiops , Cyclin A2/biosynthesis , Cyclin B1/biosynthesis , G1 Phase , Humans , Indoles/pharmacology , Mice , Mice, Inbred C57BL , Nitrophenols/pharmacology , Piperazines/pharmacology , Pyrroles/pharmacology , Resting Phase, Cell Cycle , SARS-CoV-2 , Sulfonamides/pharmacology , Thymidine Kinase/biosynthesis , Vero Cells
2.
J Virol ; 95(24): e0139921, 2021 11 23.
Article in English | MEDLINE | ID: covidwho-1443355

ABSTRACT

Targeting host factors is a promising strategy to develop broad-spectrum antiviral drugs. Drugs targeting anti-apoptotic Bcl-2 family proteins that were originally developed as tumor suppressors have been reported to inhibit multiplication of different types of viruses. However, the mechanisms whereby Bcl-2 inhibitors exert their antiviral activity remain poorly understood. In this study, we have investigated the mechanisms by which obatoclax (OLX) and ABT-737 Bcl-2 inhibitors exhibited a potent antiviral activity against the mammarenavirus lymphocytic choriomeningitis virus (LCMV). OLX and ABT-737 potent anti-LCMV activity was not associated with their proapoptotic properties but rather with their ability to induce cell arrest at the G0/G1 phase. OLX- and ABT-737-mediated inhibition of Bcl-2 correlated with reduced expression levels of thymidine kinase 1 (TK1), cyclin A2 (CCNA2), and cyclin B1 (CCNB1) cell cycle regulators. In addition, small interfering RNA (siRNA)-mediated knockdown of TK1, CCNA2, and CCNB1 resulted in reduced levels of LCMV multiplication. The antiviral activity exerted by Bcl-2 inhibitors correlated with reduced levels of viral RNA synthesis at early times of infection. Importantly, ABT-737 exhibited moderate efficacy in a mouse model of LCMV infection, and Bcl-2 inhibitors displayed broad-spectrum antiviral activities against different mammarenaviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results suggest that Bcl-2 inhibitors, actively being explored as anticancer therapeutics, might be repositioned as broad-spectrum antivirals. IMPORTANCE Antiapoptotic Bcl-2 inhibitors have been shown to exert potent antiviral activities against various types of viruses via mechanisms that are currently poorly understood. This study has revealed that Bcl-2 inhibitors' mediation of cell cycle arrest at the G0/G1 phase, rather than their proapoptotic activity, plays a critical role in blocking mammarenavirus multiplication in cultured cells. In addition, we show that Bcl-2 inhibitor ABT-737 exhibited moderate antimammarenavirus activity in vivo and that Bcl-2 inhibitors displayed broad-spectrum antiviral activities against different mammarenaviruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Our results suggest that Bcl-2 inhibitors, actively being explored as anticancer therapeutics, might be repositioned as broad-spectrum antivirals.


Subject(s)
Apoptosis , Arenaviridae/drug effects , COVID-19/drug therapy , Proto-Oncogene Proteins c-bcl-2/metabolism , A549 Cells , Animals , Antiviral Agents/pharmacology , Apoptosis Regulatory Proteins/pharmacology , Biphenyl Compounds/pharmacology , COVID-19/virology , Cell Cycle , Cell Cycle Checkpoints/drug effects , Cells, Cultured/drug effects , Cells, Cultured/virology , Chlorocebus aethiops , Cyclin A2/biosynthesis , Cyclin B1/biosynthesis , G1 Phase , Humans , Indoles/pharmacology , Mice , Mice, Inbred C57BL , Nitrophenols/pharmacology , Piperazines/pharmacology , Pyrroles/pharmacology , Resting Phase, Cell Cycle , SARS-CoV-2 , Sulfonamides/pharmacology , Thymidine Kinase/biosynthesis , Vero Cells
3.
Respir Care ; 66(1): 113-119, 2021 01.
Article in English | MEDLINE | ID: covidwho-1389654

ABSTRACT

BACKGROUND: Low airway surface pH is associated with many airway diseases, impairs antimicrobial host defense, and worsens airway inflammation. Inhaled Optate is designed to safely raise airway surface pH and is well tolerated in humans. Raising intracellular pH partially prevents activation of SARS-CoV-2 in primary normal human airway epithelial (NHAE) cells, decreasing viral replication by several mechanisms. METHODS: We grew primary NHAE cells from healthy subjects, infected them with SARS-CoV-2 (isolate USA-WA1/2020), and used clinical Optate at concentrations used in humans in vivo to determine whether Optate would prevent viral infection and replication. Cells were pretreated with Optate or placebo prior to infection (multiplicity of infection = 1), and viral replication was determined with plaque assay and nucleocapsid (N) protein levels. Healthy human subjects also inhaled Optate as part of a Phase 2a safety trial. RESULTS: Optate almost completely prevented viral replication at each time point between 24 h and 120 h, relative to placebo, on both plaque assay and N protein expression (P < .001). Mechanistically, Optate inhibited expression of major endosomal trafficking genes and raised NHAE intracellular pH. Optate had no effect on NHAE cell viability at any time point. Inhaled Optate was well tolerated in 10 normal subjects, with no change in lung function, vital signs, or oxygenation. CONCLUSIONS: Inhaled Optate may be well suited for a clinical trial in patients with pulmonary SARS-CoV-2 infection. However, it is vitally important for patient safety that formulations designed for inhalation with regard to pH, isotonicity, and osmolality be used. An inhalational treatment that safely prevents SARS-CoV-2 viral replication could be helpful for treating patients with pulmonary SARS-CoV-2 infection.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Epithelial Cells/drug effects , Glycine/pharmacology , Isotonic Solutions/pharmacology , Lung/drug effects , SARS-CoV-2 , Virus Replication/drug effects , Administration, Inhalation , Antiviral Agents/administration & dosage , Cells, Cultured/drug effects , Glycine/administration & dosage , Healthy Volunteers , Humans , Hydrogen-Ion Concentration/drug effects , Isotonic Solutions/administration & dosage
4.
Am J Respir Crit Care Med ; 204(4): 421-430, 2021 08 15.
Article in English | MEDLINE | ID: covidwho-1180997

ABSTRACT

Rationale: Mechanical ventilation is a mainstay of intensive care but contributes to the mortality of patients through ventilator-induced lung injury. eCypA (extracellular CypA [cyclophilin A]) is an emerging inflammatory mediator and metalloproteinase inducer, and the gene responsible for its expression has recently been linked to coronavirus disease (COVID-19). Objectives: To explore the involvement of eCypA in the pathophysiology of ventilator-induced lung injury. Methods: Mice were ventilated with a low or high Vt for up to 3 hours, with or without blockade of eCypA signaling, and lung injury and inflammation were evaluated. Human primary alveolar epithelial cells were exposed to in vitro stretching to explore the cellular source of eCypA, and CypA concentrations were measured in BAL fluid from patients with acute respiratory distress syndrome to evaluate the clinical relevance. Measurements and Main Results: High-Vt ventilation in mice provoked a rapid increase in soluble CypA concentration in the alveolar space but not in plasma. In vivo ventilation and in vitro stretching experiments indicated the alveolar epithelium as the likely major source. In vivo blockade of eCypA signaling substantially attenuated physiological dysfunction, macrophage activation, and MMPs (matrix metalloproteinases). Finally, we found that patients with acute respiratory distress syndrome showed markedly elevated concentrations of eCypA within BAL fluid. Conclusions: CypA is upregulated within the lungs of injuriously ventilated mice (and critically ill patients), where it plays a significant role in lung injury. eCypA represents an exciting novel target for pharmacological intervention.


Subject(s)
Anti-Inflammatory Agents/immunology , Cyclophilin A/immunology , Inflammation/immunology , Respiration, Artificial/adverse effects , Respiratory Distress Syndrome/immunology , Respiratory Mucosa/immunology , Ventilator-Induced Lung Injury/immunology , Ventilator-Induced Lung Injury/physiopathology , Animals , COVID-19/genetics , COVID-19/physiopathology , Cells, Cultured/drug effects , Cyclophilin A/pharmacology , Humans , Inflammation/physiopathology , Male , Mice , Models, Animal , Respiratory Distress Syndrome/physiopathology , SARS-CoV-2 , Ventilator-Induced Lung Injury/genetics
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