Project description:Mycobacterial pathogens adapt to environmental stresses such as nutrient deprivation by entering a non-replicative antibiotic-tolerant state of persistence. Using a biochemically-validated data-driven approach, we identified an adaptive metabolic network underlying the mycobacterial response to starvation in M. tuberculosis, M. bovis BCG and M. smegmatis. All three species show a strong Mg+2-dependence for surviving complete nutrient deprivation, accompanied by a broad phenotypic antibiotic resistance. Multivariate analysis of RNA-seq, metabolic phenotyping and biochemical data revealed substantial metabolic remodelling involving a shift to triacylglycerol utilization with adaptation to the consequent ketoacidosis by upregulation of cytochrome P450s. Paradoxically, the ketosis-driven P450 upregulation generated substantial levels of reactive oxygen species (ROS) yet conferred hypersensitivity to killing by hydrogen peroxide-induced inactivation of the P450s that reduced ROS levels. This emergent property of starvation-induced mycobacterial persistence represents a potentially exploitable vulnerability.
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:Mycobacterium servetensis sp. nov., a novel rapid-growing mycobacterial species recovered from a human patient in Zaragoza, Spain
| PRJNA1138756 | ENA
Project description:Autosomal recessive SPPL2a, a novel genetic etiology of mycobacterial disease
Project description:Mycobacterial arabinogalactan (AG) is an essential cell wall component of Mycobacteria and a frequent structural and bio-synthetical target for anti-tuberculosis (TB) drug development. Yet, it is unclear whether mycobacterial AG is a pathogen-associated molecular pattern (PAMP) with an elusive pattern recognition receptor (PRR). Here, we report that mycobacterial AG is recognized by galectin-9 and exacerbates mycobacterial infection. Administration of AG-specific aptamers inhibited cellular infiltration caused by Mycobacterium tuberculosis (Mtb) or Mycobacterium bovis BCG, and moderately increased survival of Mtb-infected mice or Mycobacterium marinum-infected zebrafish. AG interacted with carbohydrate recognition domain (CRD) 2 of galectin-9 with high affinity, and galectin-9 associated with transforming growth factor β-activated kinase 1 (TAK1) via CRD2 to trigger subsequent activation of extracellular signal-regulated kinase (ERK) as well as induction of the expression of matrix metalloproteinases (MMPs). Moreover, deletion of galectin-9 or inhibition of MMPs blocked AG-induced pathological impairments in the lung, and the AG-galectin-9 axis aggravated the process of Mtb infection in mice. These results demonstrate that AG is an important virulence factor of mycobacteria and galectin-9 is a novel receptor for Mtb and other mycobacteria, paving the way for the development of novel effective TB immune modulators.
Project description:The immunomodulatory mycobacterial surface antigen lipoarabinomannan (LAM) with its immunogenic glycan component arabinomannan (AM) facilitates Mycobacterium tuberculosis’ (Mtb) escape from the host’s immune response. Some but not all antibodies against AM can protect against TB. To better understand which of AM’s structures to target, we must first identify the spectrum of its epitopes. Through isolating and characterizing a panel of novel human mAbs with binding to distinct AM OS motifs, we further defined the glycan epitope structures, identified a new epitope, and determined their differences among mycobacterial strains.
Project description:Related surrogate species are often used to study the molecular basis of pathogenicity of a pathogen on the basis of a shared set of biological features generally attributable to a shared core genome consisting of orthologous genes. An important and understudied aspect, however, is the extent to which regulatory features affecting the expression of such shared genes are present in both species. Here we report on an analysis of whole transcriptome maps for an important member of the TB complex Mycobacterium bovis and a closely related model organism for studying mycobacterial pathogenicity Mycobacterium marinum. Predict transcription start site