Berberine and Obatoclax Inhibit SARS-Cov-2 Replication in Primary Human Nasal Epithelial Cells In Vitro.

Finny Varghese,Gerco Den Hartog,Arjan Van Laarhoven,Pascal Miesen,Marc Eleveld,Niels Van Heerbeek,Ronald Van Rij,Marien De Jonge,Gijs Overheul,Esther Van Woudenbergh,Lisa Kurver

doi:10.3390/v13020282

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a new human pathogen in late 2019 and it has infected over 100 million people in less than a year. There is a clear need for effective antiviral drugs to complement current preventive measures, including vaccines. In this study, we demonstrate that berberine and obatoclax, two broad-spectrum antiviral compounds, are effective against multiple isolates of SARS-CoV-2. Berberine, a plant-derived alkaloid, inhibited SARS-CoV-2 at low micromolar concentrations and obatoclax, which was originally developed as an anti-apoptotic protein antagonist, was effective at sub-micromolar concentrations. Time-of-addition studies indicated that berberine acts on the late stage of the viral life cycle. In agreement, berberine mildly affected viral RNA synthesis, but it strongly reduced infectious viral titers, leading to an increase in the particle-to-pfu ratio. In contrast, obatoclax acted at the early stage of the infection, which is in line with its activity to neutralize the acidic environment in endosomes. We assessed infection of primary human nasal epithelial cells that were cultured on an air-liquid interface and found that SARS-CoV-2 infection induced and repressed expression of specific sets of cytokines and chemokines. Moreover, both obatoclax and berberine inhibited SARS-CoV-2 replication in these primary target cells. We propose berberine and obatoclax as potential antiviral drugs against SARS-CoV-2 that could be considered for further efficacy testing.

Highlights

Licensee MDPI, Basel, Switzerland.Coronaviruses form a group of respiratory viruses in the order Nidovirales that possess a positive-sense RNA genome of approximately 30 kb [1]
BBR and OLX have shown antiviral activity against viruses from multiple families [21,22,23,24,25]. We tested these compounds against SARS-CoV-2 in Vero E6 cells
At a low multiplicity of infection (MOI) of 0.01, SARS-CoV-2 titers peaked at 24 h post-infection (Figure S1A)

Summary

Introduction

Licensee MDPI, Basel, Switzerland.Coronaviruses form a group of respiratory viruses in the order Nidovirales that possess a positive-sense RNA genome of approximately 30 kb [1]. In permissive cells lacking TMPRSS2, receptor binding is most likely followed by dynamin and clathrin-mediated endocytosis of the virus particle into endosomal compartments [11]. Acidification of these compartments leads to the activation of cathepsin-B/L proteases that cleave the spike protein, initiating membrane fusion and release of the encapsidated viral RNA into the cytoplasm [12,13,14]. The viral positive-sense RNA genome is translated into two open reading frames that encode for several non-structural proteins (reviewed in [15,16,17]). These proteins constitute the machinery that replicates the viral RNA and transcribes subgenomic

Methods

Results

Conclusion