Mycobacterium tuberculosis Thioredoxin Reductase Is Essential for Thiol Redox Homeostasis but Plays a Minor Role in Antioxidant Defense

PLoS Pathogens

Carolina Trujillo¹  Joshua B. Wallach¹  Ruojun Wang¹  Sabine Ehrt¹  Kan Lin¹  Kathryn M. O'Brien²  Dirk Schnappinger² 

[1] Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America;Program in Immunology and Microbial Pathogenesis, Weill Graduate School of Medical Sciences of Cornell University, New York, New York, United States of America

关键词: Mycobacterium tuberculosis;    Lysis (medicine);    Sulfur;    Oxidative stress;    DNA metabolism;    Cysteine;    Antioxidants;    Plasmid construction;   

DOI  :  10.1371/journal.ppat.1005675

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Mycobacterium tuberculosis (Mtb) must cope with exogenous oxidative stress imposed by the host. Unlike other antioxidant enzymes, Mtb’s thioredoxin reductase TrxB2 has been predicted to be essential not only to fight host defenses but also for in vitro growth. However, the specific physiological role of TrxB2 and its importance for Mtb pathogenesis remain undefined. Here we show that genetic inactivation of thioredoxin reductase perturbed several growth-essential processes, including sulfur and DNA metabolism and rapidly killed and lysed Mtb. Death was due to cidal thiol-specific oxidizing stress and prevented by a disulfide reductant. In contrast, thioredoxin reductase deficiency did not significantly increase susceptibility to oxidative and nitrosative stress. In vivo targeting TrxB2 eradicated Mtb during both acute and chronic phases of mouse infection. Deliberately leaky knockdown mutants identified the specificity of TrxB2 inhibitors and showed that partial inactivation of TrxB2 increased Mtb’s susceptibility to rifampicin. These studies reveal TrxB2 as essential thiol-reducing enzyme in Mtb in vitro and during infection, establish the value of targeting TrxB2, and provide tools to accelerate the development of TrxB2 inhibitors.

【 授权许可】

CC BY