ABSTRACT
The spread of SARS-CoV-2 and ongoing COVID-19 pandemic underscores the need for new treatments. Here we report that cannabidiol (CBD) inhibits infection of SARS-CoV-2 in cells and mice. CBD and its metabolite 7-OH-CBD, but not THC or other congeneric cannabinoids tested, potently block SARS-CoV-2 replication in lung epithelial cells. CBD acts after viral entry, inhibiting viral gene expression and reversing many effects of SARS-CoV-2 on host gene transcription. CBD inhibits SARS-CoV-2 replication in part by up-regulating the host IRE1α RNase endoplasmic reticulum (ER) stress response and interferon signaling pathways. In matched groups of human patients from the National COVID Cohort Collaborative, CBD (100 mg/ml oral solution per medical records) had a significant negative association with positive SARS-CoV-2 tests. This study highlights CBD as a potential preventative agent for early-stage SARS-CoV-2 infection and merits future clinical trials. We caution against use of non-medical formulations including edibles, inhalants or topicals as a preventative or treatment therapy at the present time.
Subject(s)
Antiviral Agents/pharmacology , Cannabidiol/pharmacology , Host-Pathogen Interactions/drug effects , Immunity, Innate/drug effects , SARS-CoV-2/drug effects , A549 Cells , Animals , Antiviral Agents/chemistry , COVID-19/virology , Cannabidiol/chemistry , Cannabidiol/metabolism , Chlorocebus aethiops , Endoplasmic Reticulum Stress/drug effects , Endoribonucleases/genetics , Endoribonucleases/metabolism , Epithelial Cells/virology , Female , Gene Expression Regulation, Viral/drug effects , Host-Pathogen Interactions/physiology , Humans , Interferons/metabolism , Mice , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , SARS-CoV-2/physiology , Vero Cells , Virus Internalization/drug effects , Virus Replication/drug effects , COVID-19 Drug TreatmentABSTRACT
We developed a SARS-CoV-2 vaccine candidate (CoV-RBD121-NP) comprised of a tobacco mosaic virus-like nanoparticle conjugated to the receptor-binding domain of the spike glycoprotein of SARS-CoV-2 fused to a human IgG1 Fc domain. CoV-RBD121-NP elicits strong antibody responses in C57BL/6 mice and is stable for up to 12 months at 2-8 or 22-28 °C. Here, we showed that this vaccine induces a strong neutralizing antibody response in K18-hACE2 mice. Furthermore, we demonstrated that immunization protects mice from virus-associated mortality and symptomatic disease. Our data indicated that a sufficient pre-existing pool of neutralizing antibodies is required to restrict SARS-CoV-2 replication upon exposure and prevent induction of inflammatory mediators associated with severe disease. Finally, we identified a potential role for CXCL5 as a protective cytokine in SARS-CoV-2 infection. Our results suggested that disruption of the CXCL5 and CXCL1/2 axis may be important early components of the inflammatory dysregulation that is characteristic of severe cases of COVID-19.
ABSTRACT
There is an urgent need for antiviral agents that treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We screened a library of 1900 clinically safe drugs against OC43, a human beta coronavirus that causes the common cold, and evaluated the top hits against SARS-CoV-2. Twenty drugs significantly inhibited replication of both viruses in cultured human cells. Eight of these drugs inhibited the activity of the SARS-CoV-2 main protease, 3CLpro, with the most potent being masitinib, an orally bioavailable tyrosine kinase inhibitor. X-ray crystallography and biochemistry show that masitinib acts as a competitive inhibitor of 3CLpro. Mice infected with SARS-CoV-2 and then treated with masitinib showed >200-fold reduction in viral titers in the lungs and nose, as well as reduced lung inflammation. Masitinib was also effective in vitro against all tested variants of concern (B.1.1.7, B.1.351, and P.1).