High-Content Screening of Eukaryotic Kinase Inhibitors Identify CHK2 Inhibitor Activity Against Mycobacterium tuberculosis.

Tirosh Shapira,Joseph D Chao,Virginia Pichler,Yossef Av-Gay,Tom Pfeifer,Leah Rankine-Wilson,Celine Rens

doi:10.3389/fmicb.2020.553962

Abstract

A screen of a eukaryotic kinase inhibitor library in an established intracellular infection model identified a set of drug candidates enabling intracellular killing of Mycobacterium tuberculosis (M.tb). Screen validity was confirmed internally by a Z′ = 0.5 and externally by detecting previously reported host-targeting anti-M.tb compounds. Inhibitors of the CHK kinase family, specifically checkpoint kinase 2 (CHK2), showed the highest inhibition and lowest toxicity of all kinase families. The screen identified and validated DDUG, a CHK2 inhibitor, as a novel bactericidal anti-M.tb compound. CHK2 inhibition by RNAi phenocopied the intracellular inhibitory effect of DDUG. DDUG was active intracellularly against M.tb, but not other mycobacteria. DDUG also had extracellular activity against 4 of 12 bacteria tested, including M.tb. Combined, these observations suggest DDUG acts in tandem against both host and pathogen. Importantly, DDUG’s validation highlights the screening and analysis methodology developed for this screen, which identified novel host-directed anti-M.tb compounds.

Highlights

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) infects one quarter of the world’s population and kills 1.5–2 million people annually, with a global case fatality rate of 16% and a poor treatment success rate of 55% for multidrug resistant TB (WHO, 2018)
Current treatment for tuberculosis involves a cocktail of four first-line drugs including rifampicin, isoniazid, ethambutol, and pyrazinamide for 6–9 months (CDC, 2016), often involving patient isolation in treatment facilities specializing in tuberculosis management
To identify host-targeting anti-M.tb compounds, we screened the OICR Kinase library, a small library of kinase inhibitors at various stages of clinical trials, or those used as molecular tools in kinase-inhibitory studies

Summary

Introduction

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) infects one quarter of the world’s population and kills 1.5–2 million people annually, with a global case fatality rate of 16% and a poor treatment success rate of 55% for multidrug resistant TB (WHO, 2018). Current treatment for tuberculosis involves a cocktail of four first-line drugs including rifampicin, isoniazid, ethambutol, and pyrazinamide for 6–9 months (CDC, 2016), often involving patient isolation in treatment facilities specializing in tuberculosis management. Second-line drugs are intended to be used sparingly due to decreased efficacy and greater toxicity-associated complications, as well as to limit the emergence of extensively drug resistant strains. Identifying the mechanisms of action of current drugs, as well as understanding the mechanisms of host-pathogen interactions between M.tb and alveolar macrophage to generate new targets for drug intervention, is fundamental to this effort (Parish, 2020)

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