Targeting HIV-1 RNase H: N'-(2-Hydroxy-benzylidene)-3,4,5-Trihydroxybenzoylhydrazone as Selective Inhibitor Active against NNRTIs-Resistant Variants.

Angela Corona,Roger Badia,Claudia Del Vecchio,Dominga Rogolino,Eva Riveira-Muñoz,Ester Ballana,Francesca Esposito,Mauro Carcelli,José A Esté,Enzo Tramontano,Cristina Parolin,Simona Distinto,Nicole Grandi

doi:10.3390/v12070729

Abstract

HIV-1 infection requires life-long treatment and with 2.1 million new infections/year, faces the challenge of an increased rate of transmitted drug-resistant mutations. Therefore, a constant and timely effort is needed to identify new HIV-1 inhibitors active against drug-resistant variants. The ribonuclease H (RNase H) activity of HIV-1 reverse transcriptase (RT) is a very promising target, but to date, still lacks an efficient inhibitor. Here, we characterize the mode of action of N’-(2-hydroxy-benzylidene)-3,4,5-trihydroxybenzoylhydrazone (compound 13), an N-acylhydrazone derivative that inhibited viral replication (EC50 = 10 µM), while retaining full potency against the NNRTI-resistant double mutant K103N-Y181C virus. Time-of-addition and biochemical assays showed that compound 13 targeted the reverse-transcription step in cell-based assays and inhibited the RT-associated RNase H function, being >20-fold less potent against the RT polymerase activity. Docking calculations revealed that compound 13 binds within the RNase H domain in a position different from other selective RNase H inhibitors; site-directed mutagenesis studies revealed interactions with conserved amino acid within the RNase H domain, suggesting that compound 13 can be taken as starting point to generate a new series of more potent RNase H selective inhibitors active against circulating drug-resistant variants.

Highlights

The number of people worldwide infected with HIV-1 in 2019 has been estimated to be around 37.9 million [1]
To determine the mode of action of N-acylhydrazone analogs that displayed selective inhibition of HIV-1 reverse transcriptase (RT) ribonuclease H (RNase H) associated function and to acquire information useful to optimize the scaffold, a series of cell -based and enzymatic assays were performed on compound 13
Among the many molecules identified as HIV-1 RT-associated RNase H inhibitors the most potent inhibitors act by coordinating the ionic cofactors within the RNase H active sites [20,23]

Summary

Introduction

The number of people worldwide infected with HIV-1 in 2019 has been estimated to be around 37.9 million [1]. Optimum treatment regimens consist of a combination of two [2] or more antiretrovirals. Despite promising efforts, presently approved treatments do not allow immunization of people [5] or the eradication of the infection [6], requiring life-long treatment with optimal adherence. Only 64.6% of HIV-1 infected people are accessing antiretroviral therapy [1]. Lack of treatment adherence and suboptimal coverage of the infected population cause the emergence of drug-resistant variants (DRV) and treatment failure [7]. DRV transmission narrows the options for treatment and is a major concern that requires an optimized therapy [8,9,10]. There is a constant need to explore new drugs and new targets for salvage therapy

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