Mycobacterium tuberculosis small RNA MTS1338 is required for bacterial virulence and regulates the expression of an immune-evasion molecules
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ABSTRACT:
ORGANISM(S): Mycolicibacterium smegmatis
PROVIDER: GSE150815 | GEO | 2020/08/31
REPOSITORIES: GEO
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Project description:DosR is the regulator of a two-component system in mycobacteria that senses oxygen concentration and the redox state of the cells. To determine the DosR regulon, the transcriptomes of M. smegmatis mc2155 and the M-NM-^TdosR cells were compared by microarray at 10 hours following induction of oxygen-limitation in serum vials. 4 biological replicates incl. 2 dye swaps. 3 technical replicates per array
2014-07-10 | E-GEOD-56083 | biostudies-arrayexpress
Project description:Mycobacterium smegmatis is a model non-pathogenic mycobacterium that is efficiently killed by macrophages. Here, we explore the role of NF-?B in the innate immune response, focusing in detail on the mechanisms of the first killing period (1-4h) of M. smegmatis which coincides with phagosome-lysosome fusion. We show that infection of macrophages with M. smegmatis induces an activation of NF-?B and this activation is required for killing since treatment of macrophages with NF-?B inhibitors or siRNA silencing of the NF-?B subunit p65 increases bacterial survival. NF-?B induced proteins were thus hypothesized to be essential during the first phase of M. smegmatis killing. We therefore identified, using RNA microarray, the genes that were regulated during infection in the absence and presence of NF-?B inhibitors. By subtraction this provided a list of pro-inflammatory proteins that were under the control of NF-?B and putatively involved in the killing response. Among these category of genes were those for lysosomal enzymes and membrane trafficking regulators, including Cathepsins, LAMP-2 and Rab34, are regulated by NF-?B. Moreover, inhibition of NF-?B signaling retarded the delivery of v-ATPase, LAMP-2, CtsZ and CtsH thereby impairing the maturation of mycobacterial phagosomes. Collectively; our data provide the first compelling evidence that the innate immune response via NF-?B activation is linked to phagosome fusion with lysosomes that is essential for killing of mycobacteria. Keywords: NFkB inhibitor treated vs untreated The study includes J774 macrophage cell lines which are infected with Mycobacterium smegmatis in the presence and absense of NFkB inhibitor SC-514.Total RNA was isolated from individual samples and each sample was hybridised to CodeLink Mouse whole genome bioarray slides.This study was intended to know the role of NFkB regulated genes in killing non-pathogenic mycobacteria during 4 hour post infection of macrophages.
2007-10-23 | E-GEOD-8999 | biostudies-arrayexpress
Project description:Mycobacterium smegmatis is a model non-pathogenic mycobacterium that is efficiently killed by macrophages. Here, we explore the role of NF-κB in the innate immune response, focusing in detail on the mechanisms of the first killing period (1-4h) of M. smegmatis which coincides with phagosome-lysosome fusion. We show that infection of macrophages with M. smegmatis induces an activation of NF-κB and this activation is required for killing since treatment of macrophages with NF-κB inhibitors or siRNA silencing of the NF-κB subunit p65 increases bacterial survival. NF-κB induced proteins were thus hypothesized to be essential during the first phase of M. smegmatis killing. We therefore identified, using RNA microarray, the genes that were regulated during infection in the absence and presence of NF-κB inhibitors. By subtraction this provided a list of pro-inflammatory proteins that were under the control of NF-κB and putatively involved in the killing response. Among these category of genes were those for lysosomal enzymes and membrane trafficking regulators, including Cathepsins, LAMP-2 and Rab34, are regulated by NF-κB. Moreover, inhibition of NF-κB signaling retarded the delivery of v-ATPase, LAMP-2, CtsZ and CtsH thereby impairing the maturation of mycobacterial phagosomes. Collectively; our data provide the first compelling evidence that the innate immune response via NF-κB activation is linked to phagosome fusion with lysosomes that is essential for killing of mycobacteria. Keywords: NFkB inhibitor treated vs untreated
2007-10-23 | GSE8999 | GEO
Project description:In this study, we used mass spectrometry-based discovery proteomic analysis to examine the cell-wide changes of Mycobacterium smegmatis, in response to sub-lethal concentrations of H2O2 and nitric oxide (NO) over time. Preliminary results have shown that sub-lethal concentrations of reactive oxygen and nitrogen species may act as signalling molecules by playing a role in the overall protein abundance that may be conducive to survival in vivo. The presented study showed that both treatments induced: the DosR regulon, alterations in protein expression and lipid metabolism. In addition to the proteomic changes observed, we have also observed increased survival after macrophage infection of Mycobacterium smegmatis pre-exposed to sub-lethal doses of H2O2 or DETA-NO. ¬ In total, 27 samples yielded approximately 3300 M. smegmatis protein group identifications. More in-depth analysis of this new dataset will provide a better understanding as to the inner workings of mycobacteria under oxidative and nitrosative stress and potential mechanisms by which exposure to sub-lethal concentrations of stressors results in an increased resistance to stress.
2019-11-12 | PXD010020 | Pride
Project description:BACKGROUND: The ability to adapt to environments with fluctuating nutrient availability is vital for bacterial survival. Although essential for growth, few nitrogen metabolism genes have been identified or fully characterised in mycobacteria and nitrogen stress survival mechanisms are unknown. RESULTS: A global transcriptional analysis of the mycobacterial response to nitrogen stress, showed a significant change in the differential expression of 16% of the Mycobacterium smegmatis genome. Gene expression changes were mapped onto the metabolic network using Active Modules for Bipartite Networks (AMBIENT) to identify metabolic pathways showing coordinated transcriptional responses to the stress. AMBIENT revealed several key features of the metabolic response not identified by KEGG enrichment alone. Down regulated reactions were associated with the general reduction in cellular metabolism as a consequence of reduced growth rate. Up-regulated modules highlighted metabolic changes in nitrogen assimilation and scavenging, as well as reactions involved in hydrogen peroxide metabolism, carbon scavenging and energy generation. CONCLUSIONS: Application of an Active Modules algorithm to transcriptomic data identified key metabolic reactions and pathways altered in response to nitrogen stress, which are central to survival under nitrogen limiting environments. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-140]
2013-06-10 | E-BUGS-140 | biostudies-arrayexpress
Project description:DosR is the regulator of a two-component system in mycobacteria that senses oxygen concentration and the redox state of the cells.
2014-07-10 | GSE56083 | GEO
Project description:Mechanisms governing Mycobacterium tuberculosis acid-fastness and its capacity to induce long-term infections remain unknown. Serine/Threonine phosphorylation represents an emerging theme allowing mycobacteria to adapt their cell envelope structure/composition in response to environmental changes. We addressed whether phosphorylation of KasB, a mycolic acid biosynthetic enzyme, modulates M. tuberculosis pathogenicity. Phosphorylation of KasB occurred at Thr334 and Thr336 in vitro and in mycobacteria. A mutant strain bearing an kasB_T334D/T336D allele, mimicking constitutive KasB phosphorylation, was generated by specialized linkage transduction. This resulted in shortened mycolic acids and the lack of trans-cyclopropanation. Structural/modeling analyses revealed Thr334 and Thr336 in the vicinity of the catalytic triad, implying that phosphorylation of these residues impaired KasB activity. Importantly, the phosphomimetic strain lost acid-fast staining and was more attenuated than a kasB deletion mutant in immunocompetent and immunodeficient mice. The absence of lung pathology and mortality infers this mutant to represent a valuable vaccine candidate. This work emphasizes the critical role of Ser/Thr kinase-dependent signaling in controlling mycolic acid elongation, acid-fastness, virulence and has important clinical implications for diagnosis of latent infections. Transcriptome of kasB null, phosphoablative, and phosphomimetic mutants compared to parental. Triplicate 10ml cultures of M. tuberculosis CDC1551 and kasB null, phosphoablative, and phosphomimetic mutants were grown to OD 1.0 and harvested for transcriptional profiling.
2014-04-01 | E-GEOD-47640 | biostudies-arrayexpress
Project description:Mechanisms governing Mycobacterium tuberculosis acid-fastness and its capacity to induce long-term infections remain unknown. Serine/Threonine phosphorylation represents an emerging theme allowing mycobacteria to adapt their cell envelope structure/composition in response to environmental changes. We addressed whether phosphorylation of KasB, a mycolic acid biosynthetic enzyme, modulates M. tuberculosis pathogenicity. Phosphorylation of KasB occurred at Thr334 and Thr336 in vitro and in mycobacteria. A mutant strain bearing an kasB_T334D/T336D allele, mimicking constitutive KasB phosphorylation, was generated by specialized linkage transduction. This resulted in shortened mycolic acids and the lack of trans-cyclopropanation. Structural/modeling analyses revealed Thr334 and Thr336 in the vicinity of the catalytic triad, implying that phosphorylation of these residues impaired KasB activity. Importantly, the phosphomimetic strain lost acid-fast staining and was more attenuated than a kasB deletion mutant in immunocompetent and immunodeficient mice. The absence of lung pathology and mortality infers this mutant to represent a valuable vaccine candidate. This work emphasizes the critical role of Ser/Thr kinase-dependent signaling in controlling mycolic acid elongation, acid-fastness, virulence and has important clinical implications for diagnosis of latent infections.
2014-04-01 | GSE47640 | GEO
Project description:Mycobacterium tuberculosis has a complex cell envelope that is remodelled throughout infection to respond and survive the hostile and variable intracellular conditions within the host. Despite the importance of cell wall homeostasis in pathogenicity, little is known about the environmental signals and regulatory networks controlling cell wall biogenesis in mycobacteria. The mycolic acid desaturase regulator (MadR) is a transcriptional repressor responsible for regulation of the essential aerobic desaturases desA1 and desA2 that are differentially regulated throughout infection along with mycolate modification genes and thus, likely involved in mycolic acid remodelling. Here we generated a madR null mutant in M. smegmatis that exhibited traits of an impaired cell wall with increased permeability, susceptibility to rifampicin and cell surface disruption as a consequence of desA1/desA2 dysregulation. Analysis of mycolic acids revealed the presence of a highly desaturated mycolate in the null mutant that exists in relative trace amounts in the wildtype, but increases in abundance upon cell surface disruption as a result of relieved repression on the desA1/desA2 promoters. Transcriptomic profiling confirmed MadR as a cell surface disruption responsive regulator of desA1/desA2 and further implicating it in the control of bespoke β-oxidation pathways and transport evolutionarily diversified subnetworks associated with virulence. In vitro characterisation of MadR using electromobility shift assays and analysis of binding affinities is suggestive of a unique acyl-CoA pool sensing mechanism, whereby MadR is able to bind a range of acyl-CoA but MadR repression of desA1/desA2 promoters is only relieved upon binding of saturated acyl-CoA of chain length C16-C24. We propose this acyl effector ligand mechanism as distinct to other regulators of mycolic acid biosynthesis or fatty acid desaturases and places MadR as the key regulatory checkpoint that coordinates mycolic acid remodelling in response to host derived cell surface perturbation
2022-01-01 | GSE171759 | GEO
Project description:Determining the M. smegmatis DosR regulon
| PRJNA242381 | ENA