MadR transcriptional regulation of mycolic acid biosynthesis in mycobacteria
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA720822 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14195100_1.fastq.gz | Fastqsanger.gz | |||
| SRR14195100_2.fastq.gz | Fastqsanger.gz | |||
| SRR14195101_1.fastq.gz | Fastqsanger.gz | |||
| SRR14195101_2.fastq.gz | Fastqsanger.gz | |||
| SRR14195102_1.fastq.gz | Fastqsanger.gz |
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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:The spread of antibiotic resistance is a major challenge for treatment of Mycobacterium tuberculosis infection. In addition, efficacy of drugs is often limited by the restricted permeability of the mycomembrane. Frontline antibiotics inhibit mycomembrane biosynthesis leading to rapid cell death. Inspired by this mechanism we exploit β-lactones as putative mycolic acid mimics to block serine hydrolases involved in their biosynthesis. Among a collection of β-lactones we found one hit with potent anti-mycobacterial and bactericidal activity. Chemical proteomics using an alkynylated probe identified Pks13 and Ag85 serine hydrolases as major targets. Validation via enzyme assays and customized 13C metabolite profiling showed that both targets are functionally impaired by the β-lactone. Co-administration with front-line antibiotics enhanced the potency against M. tuberculosis by more than 100-fold demonstrating a therapeutic potential of targeting mycomembrane biosynthesis serine hydrolases.
2022-01-19 | PXD007699 | Pride
Project description:We constructed mycolic acid synthesis key gene pks13 mutant strain and analyzed its impacts on whole cell at gene expression level compared to the wild-type ATCC13869.
2018-01-01 | GSE104833 | GEO
Project description:<p>Cyclic di-GMP (c-di-GMP) is a well-known second messenger that plays a key role in many physiological processes in bacteria. The synthesis of lipids is essential for bacterial biofilm formation. However, whether c-di-GMP signaling modulates the synthesis of lipid and further regulates biofilm formation in mycobacteria is unclear, and the c-di-GMP receptor involved remains unknown. In this study, we characterized the nucleoid-associated protein (NAP) Lsr2 as a novel c-di-GMP receptor in mycobacteria. c-di-GMP specifically binds to Lsr2 at a ratio of 1:1. We showed that c-di-GMP promotes mycobacterial biofilm formation in a manner dependent on Lsr2. Furthermore, Lsr2 mediates the synthesis of keto-mycolic acid, the lipid component of the mycobacterial cell wall, by positively regulating the expression of HadD, a (3R)-hydroxyacyl-ACP dehydratase, thus, Lsr2 ultimately controls biofilm formation. Finally, c-di-GMP promotes the positive regulation of HadD by Lsr2 and mycobacterial biofilm formation. Thus, we report a novel c-di-GMP receptor that links the second messenger’s function to lipid synthesis and biofilm formation in mycobacteria.</p>
2023-12-12 | MTBLS7053 | MetaboLights
Project description:One of the dominant features of the biology of Mycobacterium tuberculosis, and other mycobacteria, is the mycobacterial cell envelope with its exceptional complex composition. Mycolic acids are major and very specific components of the cell envelope and play a key role in its architecture and impermeability. Biosynthesis of mycolic acid (MA) precursors requires two types of fatty acid synthases, FAS I and FAS II, which should work in concert in order to keep lipid homeostasis tightly regulated. Both FAS systems are regulated at their transcriptional level by specific regulatory proteins. FasR regulates components of the FAS I system, whereas MabR and FadR regulate components of the FAS II system. In this article, by constructing a tight mabR conditional mutant in Mycobacterium smegmatis mc2155, we demonstrated that sub-physiological levels of MabR lead to a downregulation of the fasII genes, inferring that this protein is a transcriptional activator of the FAS II system. In vivo labelling experiments and lipidomic studies carried out in the wild-type and the mabR conditional mutant demonstrated that under conditions of reduced levels of MabR, there is a clear inhibition of biosynthesis of MAs, with a concomitant change in their relative composition, and of other MA-containing molecules. These studies also demonstrated a change in the phospholipid composition of the membrane of the mutant strain, with a significant increase of phosphatidylinositol. Gel shift assays carried out with MabR and PfasII as a probe in the presence of different chain-length acyl-CoAs strongly suggest that molecules longer than C18 can be sensed by MabR to modulate its affinity for the operator sequences that it recognizes, and in that way switch on or off the MabR-dependent promoter. Finally, we demonstrated the direct role of MabR in the upregulation of the fasII operon genes after isoniazid treatment.
| S-EPMC5541348 | biostudies-literature
Project description:Background: Mtb's cell wall comprises peptidoglycan, arabinogalactan, and mycolic acids linked to capsule proteins and polysaccharides by noncovalent bonds. Cell division requires extensive remodeling by inserting cell wall-building subunits, which require multiple enzymes to ensure precision and accuracy during the addition and conjugation of biomolecules to the cell wall. Approximately 35% of division and cell wall cluster operon genes are involved in cell wall biosynthesis, 22% in cell division, and 43% are still unstudied. Results: Rv2166c was examined in M. smegmatis, a substitute for M. tuberculosis, using three strains: CRISPR-Cas12a-knockout ∆Ms_4236, complemented ∆Ms_4236::Rv2166c, and pALACE transformed Ms_Vec were grown at 370C in 7H9 or 7H10 to evaluate phenotypic, chemical stress, and antibiotic responses in normoxia and hypoxia. We also examined the whole transcriptome to identify genes associated with MSMEG_4236 deletion of the Rv2166c homolog under normoxia and hypoxia. Deletion and overexpression of Rv2166c affect mycobacterial biofilm formation, cell elongation, colony morphology, and sliding motility in normoxia but are alleviated in hypoxia. Overexpression showed resistance to nucleic acid-target antibiotics, but sensitivity to cell wall-target drugs, yet long-term expression arrests growth. According to transcriptome investigation, the deletion of MSMEG_4236 upregulated all division and cell wall cluster operon genes, several mycolic acids and arabinogalactan biosynthesis genes and downregulated numerous promoters outside of the dcw cluster operon through binding at AAAGTG[G/T] sequence motifs. Conclusion: This study shows that the mycobacterial Rv2166c represses the division and cell wall cluster operon as a transcriptional regulator. Thus, modulating this gene's expression affects many mycobacteria phenotypes and environmental stress resistance. Several AAAGTG[G/T] motifs containing promoters have been found, demonstrating that Rv2166c regulates genes other than its operon. These data suggest that the Rv2166c can be targeted as future antituberculosis medicines.
2023-12-15 | GSE250112 | GEO
Project description:Treatment of Mycobacterium tuberculosis infections is a challenging task due to a growing number of resistant clinical isolates as well as an almost empty drug development pipeline. To identify new antibiotic hits, we screened a focused library of 400 synthetic compounds derived from a recently discovered molecule with promising anti-mycobacterial activity. A suite of more potent hit molecules was deciphered with sub-micromolar activity. Utilising tailored affinity-based probes for chemical proteomic investigations, we successfully pinpointed the mycolic acid transporter MmpL3 and two epoxide hydrolases, EphD and EphF, also linked to mycolic acid biosynthesis, as specific targets of the compounds. These targets were thoroughly and independently validated by activity assays, under- and overexpression, resistance generation, and proteomic studies. Structural refinement of the most potent hit molecules led to the development of a new lead compound that demonstrates enhanced biological activity in M. tuberculosis, low human cytotoxicity, and improved solubility and oral bioavailability − traits that are often challenging to achieve with anti-mycobacterial drugs. Overall, drug-likeness, as well as the dual mode of action, addressing the mycolic acid cell wall assembly at two distinct steps, holds significant potential for further in vivo applications.
2025-05-06 | PXD050993 | Pride
Project description:Alleviation of monocyte exhaustion by BCG derivative mycolic acid
| PRJNA1014905 | ENA
Project description:Monocyte exhaustion characterized by sustained pathogenic inflammatory and immune-suppressive features underlies the pathogenesis of sepsis induced by systemic polymicrobial infections. However, effective strategies in blocking monocyte exhaustion and restoring innate homeostasis are currently not available. In this study, we found that Methoxy-Mycolic Acid (M-MA), a branched mycolic acid derived from Mycobacterium Bovis Bacillus Calmette–Guérin (BCG), to be a potent agent in alleviating monocyte exhaustion and restoring immune homeostasis. Co-treatment of monocytes with M-MA can effectively block the expansion of exhausted Ly6Chi /CD38hi/PD-L1hi monocytes induced by repetitive LPS challenges, and restore the expression of immune-enhancing CD86 on co-treated monocytes. Functionally, M-MA treatment restored mitochondrial functions of exhausted monocytes and alleviated their suppressive activities on co-cultured T cells. Mechanistically, M-MA exerts its protective effects independent of cellular receptor TREM2, and relieves cellular stress signaling through blocking Src-STAT1 mediated pathogenic inflammatory polarization as well as reducing the production of compensatory immune suppressors TAX1BP1 and PLAC8. Our whole genome methylation analyses further revealed that M-MA can effectively erase methylation memory of exhausted monocytes, with validated restoration of plac8 methylation by M-MA. Together, our data reveal M-MA as a potent agent in restoring monocyte homeostasis with future therapeutic potential for the treatment of sepsis.
2023-12-19 | GSE242825 | GEO
Project description:Mycobacteria can synthesize NAD+ using either the de novo biosynthesis pathway or the salvage pathway. The deletion of the three genes involved specifically in the NAD+ de novo biosynthesis pathway in the human pathogen Mycobacterium tuberculosis had no effect on the growth of the strain in vivo. In contrast, the same deletion in the bovine pathogen Mycobacterium bovis resulted in a strain that could not grow in vivo and could only grow in vitro with substantial nicotinamide supplmentation. This striking difference was attributed to the known defect in the nicotinamidase PncA of M. bovis, since introducing the M. tuberculosis pncA gene into the M. bovis strain defective for de novo NAD+ biosynthesis restored growth in vitro and in vivo. This study demonstrates that NAD+ starvation is a cidal event in mycobacteria and confirms that enzymes common to the de novo and salvage pathways may be good drug targets. We also propose that simultaneously targeting both the salvage and the de novo NAD+ biosynthesis pathways represents a potentially effective way to treat infection with tubercle bacilli. To characterize the lethality induced by nicotinamide starvation transcriptional profiling of the auxotrophs was performed. Triplicate 50 mL cultures of M. tuberculosis and M. bovis Delta nadABC mutants were grown in 7H9 OADC glycerol 0.05% tween broth in 500 mL roller bottles to an OD600nm= 0.1 in a roller incubator at 37°C. The cells were washed 1x in PBS and resuspended in 50 mL 7H9 OADC glycerol 0.05% tween broth with or without 20mg/L nicotinamide and returned to the incubator. After 7 days, cultures were harvested. Three biological replicates of each of two species with one dye-flip each
2010-05-14 | E-GEOD-18909 | biostudies-arrayexpress