Novel Inhibitors of Cholesterol Degradation in Mycobacterium tuberculosis Reveal How the Bacterium’s Metabolism Is Constrained by the Intracellular Environment

PLoS Pathogens

David G. Russell¹  Wonsik Lee¹  Yancheng Liu¹  Brian C. VanderVen¹  Ruth J. Fahey¹  Robert B. Abramovitch¹  Lindsay D. Eltis²  Adam M. Crowe²  Tiansheng Wang³  David D. Deininger³  Christopher P. Locher³  Christine Memmott³  Emanuele Perola³ 

[1] Department of Microbiology and Immunology, Cornell University, Ithaca, New York, United States of America;Departments of Microbiology and Biochemistry, University of British Columbia, Vancouver, British Columbia, Canada;Vertex Pharmaceuticals Incorporated, Boston, Massachusetts, United States of America

关键词: Mycobacterium tuberculosis;    Cholesterol;    Macrophages;    Drug metabolism;    Tuberculosis drug discovery;    Propionates;    Enzyme inhibitors;    Enzyme metabolism;   

DOI  :  10.1371/journal.ppat.1004679

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Mycobacterium tuberculosis (Mtb) relies on a specialized set of metabolic pathways to support growth in macrophages. By conducting an extensive, unbiased chemical screen to identify small molecules that inhibit Mtb metabolism within macrophages, we identified a significant number of novel compounds that limit Mtb growth in macrophages and in medium containing cholesterol as the principle carbon source. Based on this observation, we developed a chemical-rescue strategy to identify compounds that target metabolic enzymes involved in cholesterol metabolism. This approach identified two compounds that inhibit the HsaAB enzyme complex, which is required for complete degradation of the cholesterol A/B rings. The strategy also identified an inhibitor of PrpC, the 2-methylcitrate synthase, which is required for assimilation of cholesterol-derived propionyl-CoA into the TCA cycle. These chemical probes represent new classes of inhibitors with novel modes of action, and target metabolic pathways required to support growth of Mtb in its host cell. The screen also revealed a structurally-diverse set of compounds that target additional stage(s) of cholesterol utilization. Mutants resistant to this class of compounds are defective in the bacterial adenylate cyclase Rv1625/Cya. These data implicate cyclic-AMP (cAMP) in regulating cholesterol utilization in Mtb, and are consistent with published reports indicating that propionate metabolism is regulated by cAMP levels. Intriguingly, reversal of the cholesterol-dependent growth inhibition caused by this subset of compounds could be achieved by supplementing the media with acetate, but not with glucose, indicating that Mtb is subject to a unique form of metabolic constraint induced by the presence of cholesterol.

【 授权许可】

CC BY