Project description:Mycobacterial infections pose a significant global health concern, requiring precise identification for effective treatment. However, diagnosing them is challenging due to inaccurate identifications and prolonged times. In this study, we aimed to develop a novel peptidome-based method using mycobacterial growth indicator tube (MGIT) cultures for faster and more accurate identification. We created the Peptide Taxonomy/Organism CHecking (PEP-TORCH), an algorithm that analyzes tryptic-peptide identified by mass spectrometry to diagnose species and subspecies with predominance scores. PEP-TORCH demonstrated 100% accuracy in identifying mycobacterial species, subspecies, and co-infections in 62 individuals suspected of mycobacterial infections, eliminating the need for a sub-solid culture procedure, the gold standard in clinical practice. A notable strength of PEP-TORCH is its ability to provide information on species and subspecies simultaneously, a process conventionally achieved sequentially. This capability significantly expedites pathogen identification. Furthermore, a targeted proteomics method was validated in 43 clinical samples using the taxa-specific peptides selected by PEP-TORCH, making them suitable as biomarkers in more clinically friendly settings. This comprehensive identification approach holds promise for streamlining treatment strategies in clinical practice.
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
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.
2021-02-17 | GSE166850 | GEO
Project description:Autosomal recessive SPPL2a, a novel genetic etiology of mycobacterial disease