Project description:Out of the 10 million of tuberculosis (TB) cases estimated in the world, around 14% are isoniazid (INH) resistant among new cases and 29% among previously treated cases in the last decade. INH is one of the oldest but also one of the more potent drugs to eliminate Mycobacterium tuberculosis (Mtb), the causing agent of TB. Because of the efficiency of isoniazid (INH) against Mycobacterium tuberculosis (Mtb), many studies are still focused in better understand its role in different bacterial metabolic pathways. We recently conducted a study that evaluated the changes in the protein abundance at different cellular fractions when clonal strains of Mtb developed INH resistance in the clinical and laboratory setting. Here, we want to establish which of the protein changes occurred or started because of the initial exposure to INH. Additionally, we wanted to evaluate if those changes happen differently in strains that are sensitive or resistant to INH, evaluating different cellular compartments from two different genetic lineages of Mtb. For this purpose, we analyzed the proteome of each cellular compartment (cytosol, cell wall, membrane and secreted proteins) through liquid chromatography (nano-HPLC) coupled to mass spectrometry using the Orbitrap Velos instrument and a t-test to perform the statistical analysis for each pair comparison.
Project description:Background: Understanding how growth state influences Mycobacterium tuberculosis responses to antibiotic exposure provides a window into drug action during patient chemotherapy. In this article, we describe the transcriptional programs mediated by isoniazid (INH) during the transition from log-phase to nonreplicating bacilli, from INH-sensitive to INH-tolerant bacilli respectively, using the Wayne model. Results: INH treatment did not elicit a transcriptional response from nonreplicating bacteria under microarophilic conditions (NRP2), unlike the induction of a robust and well-characterized INH signature in log-phase bacilli. Conclusion: The differential regulation (between drug-free NRP2 and log-phase bacilli) of genes directly implicated in INH resistance could not account for the abrogation of INH killing in nongrowing bacilli. Thus, factors affecting the requirement for mycolic acids and the redox status of bacilli are likely responsible for the reduction in INH efficacy. We speculate on additional mechanisms revealed by transcriptome analysis that might account for INH tolerance. Data is also available from <ahref=http://bugs.sgul.ac.uk/E-BUGS-104 target=_blank>BuG@Sbase</a>
Project description:To explore the mechanism of drug resistance, most works focused on resistance associated genetic mutations, whereas concerns for resistance related gene expression are relatively low. Here a global expression analysis was performed between a reference strain H37Rv and two clinical extensively drug-resistant (XDR) strains with three anti-TB drug exposures {isoniazid (INH), capreomycin (CAP), rifampicin (RIF)} Strains were grown in Middlebrook 7H9 broth supplemented with ADC, 0.05% Tween 80 and 0.2% glycerol to an OD600 of 0.5-0.6, and then respectively treated with control (water), 10×MIC INH, 1×MIC RIF and CAP for 6hr.
Project description:Tuberculosis, caused by the pathogen Mycobacterium tuberculosis is a worldwide public health threat. Mycobacterium tuberculosis is capable of resisting of various stresses in host cells including high levels of ROS and copper ions. To better understand the resistance mechanisms of mycobacteria to copper, we generated a copper-resistant strain of Mycobacterium smegmatis, mc2155-Cu from the selection of copper sulfate treated-bacteria. The mc2155-Cu strain has the 5-fold higher resistance to copper sulfate and the 2-fold higher resistance to isoniazid (INH) than its parental strain mc2155, respectively. Quantitative proteomics was carried out to find differentially expressed proteins between mc2155 and mc2155-Cu. Among 345 differentially expressed proteins, copper-translocating P-type ATPase was up-regulated, while all other ABC transporters were down-regulated in mc2155-Cu, suggesting copper-translocating P-type ATPase plays a crucial role in copper resistance. Results also indicated that the down-regulation of metabolic enzymes and decreases in cellular NAD, FAD, mycothiol, and glutamine levels in mc2155-Cu were responsible to its slow growth rate as compared to mc2155. Down-regulation of KatG2 expression in both protein and mRNA levels indicates the co-evolution of copper and INH resistance in copper resistance bacteria, and provides new evidences to understanding of the molecular mechanisms of survival of mycobacteria under stress conditions.
2016-04-13 | PXD001989 | Pride
Project description:Mutations identified in mce3R gene causing contezolid resistance in Mycobacterium tuberculosis
Project description:This project describes the isoniazid (INH) resistance acquisition event in Mycobacterium tuberculosis (Mtb) from the proteomics perspective. In this way, an exploration of the protein differences, comparing clonal INH susceptible (INHs) and INHr pairs of Mtb were evaluated. One clonal clinical and one clonal laboratory-derived Mtb pair with different susceptibility profiles to INH were studied. The laboratory INHr strain had one katG mutation (V1A), while the clinical INHr strain had two (V1A and E3V). Large-scale bacterial cultures were grown in triplicate to obtain secreted proteins as well as proteins from cell fractions. The resulting peptide solutions from all fractions were analyzed using liquid-chromatography coupled with tandem mass spectrometry (LC-MS/MS). LC-MS/MS spectra were compared against an Mtb database to determine the protein abundance. Protein abundance differences were tested by Student’s t test. Looking at the same cellular fractions, there were 25 commonly altered Mtb proteins after acquiring INH resistance. These proteins were involved in ATP synthase machinery, lipid metabolism, regulatory events, virulence, detoxification and adaptation processes.
Project description:To explore the mechanism of drug resistance, most works focused on resistance associated genetic mutations, whereas concerns for resistance related gene expression are relatively low. Here a global expression analysis was performed between a reference strain H37Rv and two clinical extensively drug-resistant (XDR) strains with three anti-TB drug exposures {isoniazid (INH), capreomycin (CAP), rifampicin (RIF)}
Project description:Isoniazid (INH) is the first-line anti-tuberculosis drug used for nearly seventy years. Metabolites of INH showed hepatotoxicity in human and tumorigenicity in rodents. However, mechanism underlying the side effects of INH is elusive. Histone acylation is known to be modulated by intracellular metabolites. Here, we report INH and its metabolites induces a novel post-translational modification (PTM) on histones, the lysine isonicotinylation (Kinic), also called 4-picolinylation, in cells and mice. INH functions as a donor to promote biosynthesis of isonicotinyl-CoA that is used for a co-factor of intracellular isonicotinylation reaction. Twenty-six isonicotinylation sites were identified on histones in HepG2 cells by mass spectrometry. Acetyltransferases CREB-binding protein (CBP) and P300 were found to catalyze histone Kinic, whilst histone deacetylase HDAC3 functions as a deisonicotinylase. MNase sensitivity assay and RNA-seq analysis showed that histone Kinic relaxes chromatin structure and promotes gene transcription. Importantly, INH-mediated histone Kinic upregulates PIK3R1 gene expression and activates PI3K/Akt/mTOR signaling pathway in liver cancer cells, linking INH to the tumorigenicity in liver. Further, Kinic was found increased in liver cancer patients with concomitant raised PIK3R1 protein level. In addition, histone Kinic also affects TNF and GABAergic synapse signaling pathways that are closely related to INH-caused side effects. Taken together, we demonstrated that lysine isonicotinylation represents the first histone acylation mark with the pyridine ring that may arise broad biological effects. Therefore, INH-induced isonicotinylation is likely a mechanism accounting for side effects in patients who taking long-term INH for anti-tuberculosis therapy and this modification may also increase cancer risk in human.
Project description:The human pathogen, Mycobacterium tuberculosis, develops a dormant infection, in which organisms survive within the body. We established a unique in vitro dormancy model based on the characterization of drug-resistance to INH and rifampin. M. tuberculosis cells were maintained in controlled and defined multiple stress conditions with low oxygen (5% dissolved oxygen tension), acid (pH 5.) along with glycerol-deprived medium conditions. To monitor gene expression changes in M. tuberculosis in response to the multiple stresses, we performed microarray analysis at the time point of 1, 2, 3, 6, and 12days after treatment. M. tuberculosis adapting to multiple stresses displayed characteristics associated with persistence in vivo, including entry into a non-replicative state and the repression of genes involved in energy regeneration. Under in vitro multiple-stresses, M. tuberculosis significantly modulated gene expression mainly in response to the starvation stresses. Cells exposed to these multiple stress conditions shows significant drug-resistance. Comparison with other in vivo expression profiles demonstrates induction of several common genes for in vitro dormancy conditions. Keywords: Stress response in time course.
Project description:The human pathogen, Mycobacterium tuberculosis, develops a dormant infection, in which organisms survive within the body. We established a unique in vitro dormancy model based on the characterization of drug-resistance to INH and rifampin. M. tuberculosis cells were maintained in controlled and defined multiple stress conditions with low oxygen (5% dissolved oxygen tension), acid (pH 5.) along with glycerol-deprived medium conditions. To monitor gene expression changes in M. tuberculosis in response to the multiple stresses, we performed microarray analysis at the time point of 1, 2, 3, 6, and 12days after treatment. M. tuberculosis adapting to multiple stresses displayed characteristics associated with persistence in vivo, including entry into a non-replicative state and the repression of genes involved in energy regeneration. Under in vitro multiple-stresses, M. tuberculosis significantly modulated gene expression mainly in response to the starvation stresses. Cells exposed to these multiple stress conditions shows significant drug-resistance. Comparison with other in vivo expression profiles demonstrates induction of several common genes for in vitro dormancy conditions. Keywords: Stress response in time course. Samples under multiple stress condition were taken at day 1, 2, 3, 6, and 12 for microarray hybridization. More than two technical replicates per biological samples with Cy3/5 dye-swaps.