Dataset Information

The Oxidative Stress Network of Mycobacterium tuberculosis Reveals Coordination between Radical Detoxification Systems.

ABSTRACT: M. tuberculosis (Mtb) survives a hostile environment within the host that is shaped in part by oxidative stress. The mechanisms used by Mtb to resist these stresses remain ill-defined because the complex combination of oxidants generated by host immunity is difficult to accurately recapitulate in vitro. We performed a genome-wide genetic interaction screen to comprehensively delineate oxidative stress resistance pathways necessary for Mtb to resist oxidation during infection. Our analysis predicted functional relationships between the superoxide-detoxifying enzyme (SodA), an integral membrane protein (DoxX), and a predicted thiol-oxidoreductase (SseA). Consistent with that, SodA, DoxX, and SseA form a membrane-associated oxidoreductase complex (MRC) that physically links radical detoxification with cytosolic thiol homeostasis. Loss of any MRC component correlated with defective recycling of mycothiol and accumulation of cellular oxidative damage. This previously uncharacterized coordination between oxygen radical detoxification and thiol homeostasis is required to overcome the oxidative environment Mtb encounters in the host.

SUBMITTER: Nambi S

PROVIDER: S-EPMC4465913 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Oxidative Stress Network of Mycobacterium tuberculosis Reveals Coordination between Radical Detoxification Systems.

Nambi Subhalaxmi S Long Jarukit E JE Mishra Bibhuti B BB Baker Richard R Murphy Kenan C KC Olive Andrew J AJ Nguyen Hien P HP Shaffer Scott A SA Sassetti Christopher M CM

Cell host & microbe 20150601 6

M. tuberculosis (Mtb) survives a hostile environment within the host that is shaped in part by oxidative stress. The mechanisms used by Mtb to resist these stresses remain ill-defined because the complex combination of oxidants generated by host immunity is difficult to accurately recapitulate in vitro. We performed a genome-wide genetic interaction screen to comprehensively delineate oxidative stress resistance pathways necessary for Mtb to resist oxidation during infection. Our analysis predic ...[more]

PMID: 26067605

Similar Datasets

Project description:BackgroundSnakebites remain a major life-threatening event worldwide. It is still difficult to make a positive identification of snake species by clinicians in both Western medicine and Chinese medicine. The main reason for this is a shortage of diagnostic biomarkers and lack of knowledge about pathways of venom-induced toxicity. In traditional Chinese medicine, snakebites are considered to be treated with wind, fire, and wind-fire toxin, but additional studies are required.MethodsCases of snakebite seen at the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine were grouped as follows: fire toxin - including four cases of bites by Agkistrodon acutus and three bites by Trimeresurus stejnegeri - and wind-fire toxin - four cases of bites by vipers and three bites by cobras. Serum protein quantification was performed using LC-MS/MS. Differential abundance proteins (DAPs) were identified from comparison of snakebites of each snake species and healthy controls. The protein interaction network was constructed using STITCH database.ResultsPrincipal component analysis and hierarchical clustering of 474 unique proteins exhibited protein expression profiles of wind-fire toxins that are distinct from that of fire toxins. Ninety-three DAPs were identified in each snakebite subgroup as compared with healthy control, of which 38 proteins were found to have significantly different expression levels and 55 proteins displayed no expression in one subgroup, by subgroup comparison. GO analysis revealed that the DAPs participated in bicarbonate/oxygen transport and hydrogen peroxide catabolic process, and affected carbon-oxygen lyase activity and heme binding. Thirty DAPs directly or indirectly acted on hydrogen peroxide in the interaction network of proteins and drug compounds. The network was clustered into four groups: lipid metabolism and transport; IGF-mediated growth; oxygen transport; and innate immunity.ConclusionsOur results show that the pathways of snake venom-induced toxicity may form a protein network of antioxidant defense by regulating oxidative stress through interaction with hydrogen peroxide.

Project description:Oxidative stress (OS) results from genetic defects or stressful environmental challenges that cause unchecked production of reactive oxygen species (ROS). OS has been implicated in many diseases due to its wide ranging damage to nucleic acids, proteins and lipids. Using Halobacterium salinarum NRC-1, an extremophile that thrives under conditions of excessive OS, we have constructed a systems model for oxidative stress response (OSR) by integrating transcriptional changes induced by treatments with H2O2 and paraquat, functional associations inferred through comparative genomics, and de novo discovered cis-regulatory motifs. Together with phenotypic analysis of mutant strains this has revealed a multi-tiered OS management program to transcriptionally coordinate three peroxidase/catalase enzymes, two superoxide dismutases, production of rhodopsins, carotenoids, and gas vesicles, metal trafficking, and various other aspects of metabolism. Remarkably, a significant fraction of this OSR was accurately recapitulated by a model that was previously constructed from cellular responses to diverse environmental perturbations –this constitutes the general stress response component. Notwithstanding this observation, comparison of the two models has identified the coordination of frontline defense and repair systems by regulatory mechanisms that are triggered uniquely by severe OS and not by other environmental stressors, including sub-inhibitory levels of redox-active metals, extreme changes in oxygen tension, and a sub-lethal dose of g rays. Mid-log phase cultures of H. salinarum NRC-1 (2 biological replicates) grown in flasks were treated with either sub-lethal concentrations of 25mM H2O2 or 4mM PQ and incubated with shaking for up to 240 min. For each treatment, two time courses were run to determine the transcriptional responses to (1) constant stress and (2) recovery of H. salinarum NRC-1 to H2O2 and PQ. During constant stress, culture aliquots (~4ml) were collected over a time course (-1, 5, 10, 20, 40, 80 and 160 minutes), centrifuged (16000g, 90 seconds) and flash frozen. For recovery, cells were first treated for 2-hours with either 25 mM H2O2 or 4mM PQ, recovered by centrifugation, washed and re-suspended in CM. Cultures were returned to the incubator with shaking and samples were taken at 0, 10, 20, 30, 40, 50, 60, 120, and 240 minutes and processed as described previously. Analysis of temporal transcriptional changes (-1, 0, 5, 10, 20, 40, 80, 160 and 320m) to sub-inhibitory concentrations of PQ (0.25mM) was also characterized. Total RNA was prepared and labeled with Alexa547 and Alexa647 dyes. Intensities were normalized between the Alexa 546 and Alexa 647 channels by scaling all intensities in one channel such that the 75th percentile in each channel was made equal.

Dataset Information

The Oxidative Stress Network of Mycobacterium tuberculosis Reveals Coordination between Radical Detoxification Systems.

Publications

The Oxidative Stress Network of Mycobacterium tuberculosis Reveals Coordination between Radical Detoxification Systems.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets