A dual drug regimen synergistically blocks human parainfluenza virus infection.

Benjamin Bailly,Ralf Altmeyer,Larissa Dirr,Mark Von Itzstein,Patrice Guillon,Ibrahim M El-Deeb

doi:10.1038/srep24138

Abstract

Human parainfluenza type-3 virus (hPIV-3) is one of the principal aetiological agents of acute respiratory illness in infants worldwide and also shows high disease severity in the elderly and immunocompromised, but neither therapies nor vaccines are available to treat or prevent infection, respectively. Using a multidisciplinary approach we report herein that the approved drug suramin acts as a non-competitive in vitro inhibitor of the hPIV-3 haemagglutinin-neuraminidase (HN). Furthermore, the drug inhibits viral replication in mammalian epithelial cells with an IC50 of 30 μM, when applied post-adsorption. Significantly, we show in cell-based drug-combination studies using virus infection blockade assays, that suramin acts synergistically with the anti-influenza virus drug zanamivir. Our data suggests that lower concentrations of both drugs can be used to yield high levels of inhibition. Finally, using NMR spectroscopy and in silico docking simulations we confirmed that suramin binds HN simultaneously with zanamivir. This binding event occurs most likely in the vicinity of the protein primary binding site, resulting in an enhancement of the inhibitory potential of the N-acetylneuraminic acid-based inhibitor. This study offers a potentially exciting avenue for the treatment of parainfluenza infection by a combinatorial repurposing approach of well-established approved drugs.

Highlights

Human parainfluenza viruses are the second most prevalent cause of acute respiratory tract infection in infants, after human respiratory syncytial virus
In the present study we look into another strategy to block HN-mediated Human parainfluenza type-3 virus (hPIV-3) infection, by investigating approved drugs, not related to N-acylneuraminic acids, that may inhibit Human parainfluenza viruses (hPIVs)-3 HN haemagglutination and neuraminidase functions
In our desire to discover novel, repurposable drugs of hPIV-3, we screened a library of 1280 USA and Internationally approved drugs in a neuraminidase activity inhibition assay using the neuraminidase substrate 2′ -(4-methylumbelliferyl) α -D-N-acetylneuraminide (MUN, 6, Fig. 1)

Summary

Introduction

Human parainfluenza viruses (hPIVs) are the second most prevalent cause of acute respiratory tract infection in infants, after human respiratory syncytial virus. Most of the compounds that have been investigated as anti-hPIV-3 agents are competitive inhibitors of HN. They are primarily N-acylneuraminic acid derivatives based on Neu5Ac2en (DANA, N-acetyl-2,3-didehydro2-deoxy-neuraminic acid), one of the first inhibitors of a broad range of neuraminidases (sialidases)[20]. The influenza virus neuraminidase inhibitor zanamivir[21,22] or derivatives of the hPIV inhibitor BCX-2798 have been the most widely studied, with the latter compounds displaying some prophylactic efficacy in a mouse model of hPIV-3 infection[17,23,24] (1–4, Fig. 1). BCX-2798 that was shown to covalently bind the key catalytic residue Tyr[530] in the HN active[26], as well as a bulky C4-substituted phenyltriazole derivative of BCX-2798 (5, Fig. 1) that was shown to be nicely accommodated into the protein’s active site and to lock open the 216-loop upon engagement[19]

Methods

Results

Conclusion