Identification of Theaflavin-3,3'-Digallate as a Novel Zika Virus Protease Inhibitor.

Xiangling Cui,Shan Cen,Jiwei Ding,Jing Wang,Chenchao Huang,Xiaoyu Li,Rui Zhou,Yongxin Zhang,Jinming Zhou,Rongyu Zhang

doi:10.3389/fphar.2020.514313

Abstract

Mounting evidence indicates that Zika virus (ZIKV) is closely related to neurological disorders such as microcephaly and Guillain-Barré syndrome. There are currently no effective vaccines and FDA-approved inhibitors against ZIKV infection. The flaviviral heterodimeric serine protease NS2B-NS3 plays an essential role in ZIKV maturation and replication, thus becoming a promising target in anti-ZIKV therapy. Herein, we developed a fluorescence-based screening assay to search for inhibitors targeting the ZIKV NS2B-NS3 protease (ZIKVpro), and identified theaflavin-3,3’-digallate (ZP10), a natural active compound derived from black tea, as a potent ZIKV protease inhibitor in vitro (IC50 = 2.3 μM). ZP10 exhibited dose-dependent inhibitory effect on ZIKV replication (EC50 = 7.65 μM). Western blot analysis suggested that ZP10 inhibited the cleavage processing of viral polyprotein precursor in cells either infected with ZIKV or expressing minimal self-cleaving proteinase NS2B-3 protease, resulting in inhibition of virus growth. Moreover, ZP10 was showed to directly bind to ZIKVpro, and a docking model further revealed that ZP10 interacted with several critical residues at the proteolytic cavity of the ZIKVpro. This study highlights that ZP10 has anti-ZIKV potency through ZIKVpro inhibition, which indicates its potential application in anti-ZIKV therapy.

Highlights

The recent outbreak of Zika virus (ZIKV) belonging to the family flaviviridae has posed a threat to human health
The findings of this study demonstrated for the first time that ZP10 has potential to target ZIKV NS2B-NS3 protease (ZIKVpro) to produce a protective effect in vitro against the infection of ZIKV, which suggests its potential application in anti-ZIKV therapy
We used benzoyl-norleucine-lysinelysine-arginine 7-amino-4-methylcoumarine (Bz-nKKR-AMC), one of the commercially available substrates for flaviviruses protease, as the substrate to assess the kinetic parameter of ZIKVpro (Phoo et al, 2016), resulting in a Km value of 30.51 μM (Figure 1D)

Summary

Introduction

The recent outbreak of Zika virus (ZIKV) belonging to the family flaviviridae has posed a threat to human health. No vaccine or therapeutic agent has been clinically approved for preventing or controlling ZIKV infection so far. This unmet medical need has motivated academia and industry to develop countermeasures. Three strategies have been developed for ZIKV drug discovery, including (1) repurposing of clinically approved drugs, (2) viral replication-based phenotypic screening for inhibitors, and (3) targeted drug discovery of viral proteins (Zou and Shi, 2019). Anti-malaria drug chloroquine (CQ) (Shiryaev et al, 2017), sofosbuvir (BullardFeibelman et al, 2017; Sacramento et al, 2017), and ribavirin (Kamiyama et al, 2017) showed great potential to be repurposed as antiviral drug for ZIKV treatment and prophylaxis

Methods

Results

Conclusion