Targeting Mycobacterium tuberculosis Sensitivity to Thiol Stress at Acidic pH Kills the Bacterium and Potentiates Antibiotics
Ontology highlight
ABSTRACT:
ORGANISM(S): Mycobacterium tuberculosis CDC1551
PROVIDER: GSE89106 | GEO | 2017/08/04
SECONDARY ACCESSION(S): PRJNA350293
REPOSITORIES: GEO
Similar Datasets
Project description:Mycobacterium tuberculosis (Mtb) must sense and adapt to immune pressures such as acidic pH during pathogenesis. The goal of this study was to isolate compounds that inhibit acidic pH resistance, thus defining virulence pathways that are vulnerable to chemotherapy. Here, we report that the compound AC2P36 selectively kills Mtb at acidic pH and potentiates the bactericidal activity of isoniazid, clofazimine, and diamide. We show that AC2P36 activity is associated with thiol stress and causes an enhanced accumulation of intracellular reactive oxygen species at acidic pH. Mechanism of action studies demonstrate that AC2P36 directly depletes Mtb thiol pools, with enhanced depletion of free thiols at acidic pH. These findings support that Mtb is especially vulnerable to thiol stress at acidic pH and that chemical depletion of thiol pools is a promising target to promote Mtb killing and potentiation of antimicrobials.
| S-EPMC5562523 | biostudies-literature
Project description:Mycobacterium tuberculosis (Mtb) senses and adapts to host immune cues as part of its pathogenesis. One environmental cue sensed by Mtb is the acidic pH of its host niche in the macrophage phagosome. Disrupting the ability of Mtb to sense and adapt to acidic pH has the potential to reduce survival of Mtb in macrophages. Previously, a high throughput screen of a ∼220 000 compound small molecule library was conducted to discover chemical probes that inhibit Mtb growth at acidic pH. The screen discovered chemical probes that kill Mtb at pH 5.7 but are inactive at pH 7.0. In this study, AC2P20 was prioritized for continued study to test the hypothesis that it was targeting Mtb pathways associated with pH-driven adaptation. RNAseq transcriptional profiling studies showed AC2P20 modulates expression of genes associated with redox homeostasis. Gene enrichment analysis revealed that the AC2P20 transcriptional profile had significant overlap with a previously characterized pH-selective inhibitor, AC2P36. Like AC2P36, we show that AC2P20 kills Mtb by selectively depleting free thiols at acidic pH. Mass spectrometry studies show the formation of a disulfide bond between AC2P20 and reduced glutathione, supporting a mechanism where AC2P20 is able to deplete intracellular thiols and dysregulate redox homeostasis. The observation of two independent molecules targeting free thiols to kill Mtb at acidic pH further supports that Mtb has restricted redox homeostasis and sensitivity to thiol-oxidative stress at acidic pH.
| S-EPMC8176622 | biostudies-literature
Project description:In this study, AC2P20 was prioritized for continued study to test the hypothesis that it was targeting Mtb pathways associated with pH-driven adaptation. RNAseq transcriptional profiling studies showed AC2P20 modulates expression of genes associated with redox-homeostasis. Gene enrichment analysis revealed that the AC2P20 transcriptional profile had significant overlap with a previously characterized pH-selective inhibitor, AC2P36. Like AC2P36, we show that AC2P20 kills Mtb by selectively depleting free thiols at acidic pH. Mass spectrometry studies show the formation of a disulfide bond between AC2P20 and reduced glutathione, supporting a mechanism where AC2P20 is able to deplete intracellular thiols and dysregulate redox homeostasis.
2021-07-02 | GSE151884 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2021-07-16 | GSE166806 | GEO
Project description:The purpose of this study was to examine how Mtb integrates acidic pH and available carbon sources as environmental cues to regulate its metabolism and growth rate. RNA-seq transcriptional profiling of M. tuberculosis growing at acidic or neutral pH, in pyruvate or glycerol, was examined. These studies identified carbon source-dependent and -independent pH-dependent adaptations.
2014-07-07 | GSE52020 | GEO
Project description:The purpose of this study was to examine how Mtb integrates acidic pH and available carbon sources as environmental cues to regulate its metabolism and growth rate. RNA-seq transcriptional profiling of M. tuberculosis growing at acidic or neutral pH, in pyruvate or glycerol, was examined. These studies identified carbon source-dependent and -independent pH-dependent adaptations. Mtb strain CDC1551 was grown in standing T-75 flasks in 40 mL of medium seeded an initial OD of 0.1. We examined medium in four conditions pH 7.0 10 mM glycerol, pH 5.7 10 mM glycerol, pH 7.0 10 mM pyruvate, pH 5.7 10 mM pyruvate. Following 3 days of incubation at 37C, RNA was isolated from the bacterial cultures and used for RNA-seq.
2014-07-07 | E-GEOD-52020 | biostudies-arrayexpress
Project description:The purpose of this study was to identify genes that are differentially expressed upon prrA overexpression, to reveal the impact of PrrA on global transcription in acidic pH and/or high chloride conditions.
2022-06-23 | GSE198998 | GEO
Project description:The purpose of this study was to determine (i) the interplay between Mycobacterium tuberculosis response to acidic pH and cholesterol, two signals experienced concurrently by the bacterium during host colonization, and (ii) the role of the transcription factor Mce3R in regulation of this response.
2023-08-23 | GSE241072 | GEO
Project description:During pathogenesis, Mycobacterium tuberculosis (Mtb) colonizes environments, such as the macrophage or necrotic granuloma, that are acidic and rich in cholesterol and fatty acids. The goal of this study was to examine how acidic pH and available carbon sources interact to regulate Mtb physiology. Here we report that Mtb growth at acidic pH requires host-associated carbon sources that function at the intersection of glycolysis and the TCA cycle, such as pyruvate, acetate, oxaloacetate and cholesterol. In contrast, in other tested carbon sources, Mtb fully arrests its growth at acidic pH and establishes a state of non-replicating persistence. Growth-arrested Mtb is resuscitated by the addition of pyruvate suggesting that growth arrest is due to a pH-dependent checkpoint on metabolism. Additionally, we demonstrate that the phoPR two-component regulatory system is required to slow Mtb growth at acidic pH and functions to maintain redox homeostasis. Transcriptional profiling and functional metabolic studies demonstrate that signals from acidic pH and carbon source are integrated to remodel pathways associated with anaplerotic central metabolism, lipid anabolism and the regeneration of oxidized cofactors. Because phoPR is required for Mtb virulence in animals, we suggest that pH-driven adaptation may be critical to Mtb pathogenesis.
| S-EPMC4177513 | biostudies-literature
Project description:In defined media supplemented with single carbon sources, Mycobacterium tuberculosis (Mtb) exhibits carbon source specific growth restriction. When supplied with glycerol as the sole carbon source at pH 5.7, Mtb establishes a metabolically active state of nonreplicating persistence known as acid growth arrest. We hypothesized that acid growth arrest on glycerol is not a metabolic restriction, but rather an adaptive response. To test this hypothesis, we selected for and identified several Mtb mutants that could grow under these restrictive conditions. All mutations were mapped to the ppe51 gene and resulted in variants with 3 different amino acid substitutions- S211R, E215K, and A228D. Expression of the ppe51 variants in Mtb promoted growth at acidic pH showing that the mutant alleles are sufficient to cause the dominant gain-of-function, Enhanced Acid Growth (EAG) phenotype. Testing growth on other single carbon sources showed the PPE51 variants specifically enhanced growth on glycerol, suggesting PPE51 plays a role in glycerol uptake. Using radiolabeled glycerol, enhanced glycerol uptake was observed in Mtb expressing the PPE51 (S211R) variant, with glycerol overaccumulation in triacylglycerol. Notably, the EAG phenotype is deleterious for growth in macrophages, where the mutants have selectively faster replication and reduced survival in activated macrophages compared to resting macrophages. Recombinant PPE51 protein exhibited differential thermostability in the wild type (WT) or S211R variants in the presence of glycerol, supporting the model that EAG substitutions alter PPE51-glycerol interactions. Together, these findings support that PPE51 variants selectively promote glycerol uptake and that slowed growth at acidic pH is an important adaptive mechanism required for macrophage pathogenesis. IMPORTANCE It is puzzling why Mycobacterium tuberculosis (Mtb) cannot grow on glycerol at acidic pH, as it has a carbon source and oxygen, everything it needs to grow. In this study, we found that Mtb limits uptake of glycerol at acidic pH to restrict its growth and that mutations in ppe51 promote uptake of glycerol at acidic pH and enable growth. That is, Mtb can grow well at acidic pH on glycerol, but has adapted instead to stop growth. Notably, ppe51 variants exhibit enhanced replication and reduced survival in activated macrophages, supporting a role for pH-dependent slowed growth during macrophage pathogenesis.
| S-EPMC9664963 | biostudies-literature