Therapeutic potential of coumestan Pks13 inhibitors for tuberculosis

Shichun Lun; Shiqi Xiao; Wei Zhang; Shuangshuang Wang; Hendra Gunosewoyo; Li-Fang Yu; William R Bishai

doi:10.1128/AAC.02190-20

Therapeutic potential of coumestan Pks13 inhibitors for tuberculosis

Antimicrob Agents Chemother. 2023 May 1;95(5):e02190-20. doi: 10.1128/AAC.02190-20. Epub 2021 Feb 8.

Authors

Shichun Lun¹, Shiqi Xiao¹, Wei Zhang², Shuangshuang Wang², Hendra Gunosewoyo³, Li-Fang Yu⁴, William R Bishai⁵

Affiliations

¹ Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
² Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, and Shanghai Key Laboratory of Green Chemistry and Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.
³ School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, Australia.
⁴ Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, and Shanghai Key Laboratory of Green Chemistry and Chemical Process, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China wbishai1@jhmi.edu lfyu@sat.ecnu.edu.cn.
⁵ Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA wbishai1@jhmi.edu lfyu@sat.ecnu.edu.cn.

Abstract

Polyketide synthase 13 (Pks13) is an important enzyme found in Mycobacterium tuberculosis (M. tuberculosis) that condenses two fatty acyl chains to produce α-alkyl β-ketoesters, which in turn serve as the precursors for the synthesis of mycolic acids that are essential building blocks for maintaining the cell wall integrity of M. tuberculosis Coumestan derivatives have recently been identified in our group as a new chemotype that exert their antitubercular effects via targeting of Pks13. These compounds were active on both drug-susceptible and drug-resistant strains of M. tuberculosis as well as showing low cytotoxicity to healthy cells and a promising selectivity profile. No cross-resistance was found between the coumestan derivatives and first-line TB drugs. Here we report that treatment of M. tuberculosis bacilli with 15 times the MIC of compound 1, an optimized lead coumestan compound, resulted in a colony forming unit (CFU) reduction from 6.0 log₁₀ units to below the limit of detection (1.0 log₁₀ units) per mL culture, demonstrating a bactericidal mechanism of action. Single dose (10 mg/kg) pharmacokinetic studies revealed favorable parameters with a relative bioavailability of 19.4%. In a mouse infection and chemotherapy model, treatment with 1 showed dose-dependent mono-therapeutic activity, whereas treatment with 1 in combination with rifampin showed clear synergistic effects. Together these data suggest that coumestan derivatives are promising agents for further TB drug development.

Abstract

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