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Nature Microbiology Oct 2023The order Corynebacteriales includes major industrial and pathogenic Actinobacteria such as Corynebacterium glutamicum or Mycobacterium tuberculosis. These bacteria have...
The order Corynebacteriales includes major industrial and pathogenic Actinobacteria such as Corynebacterium glutamicum or Mycobacterium tuberculosis. These bacteria have multi-layered cell walls composed of the mycolyl-arabinogalactan-peptidoglycan complex and a polar growth mode, thus requiring tight coordination between the septal divisome, organized around the tubulin-like protein FtsZ, and the polar elongasome, assembled around the coiled-coil protein Wag31. Here, using C. glutamicum, we report the discovery of two divisome members: a gephyrin-like repurposed molybdotransferase (Glp) and its membrane receptor (GlpR). Our results show how cell cycle progression requires interplay between Glp/GlpR, FtsZ and Wag31, showcasing a crucial crosstalk between the divisome and elongasome machineries that might be targeted for anti-mycobacterial drug discovery. Further, our work reveals that Corynebacteriales have evolved a protein scaffold to control cell division and morphogenesis, similar to the gephyrin/GlyR system that mediates synaptic signalling in higher eukaryotes through network organization of membrane receptors and the microtubule cytoskeleton.
Topics: Eukaryota; Bacterial Proteins; Cell Division; Mycobacterium tuberculosis
PubMed: 37679597
DOI: 10.1038/s41564-023-01473-0 -
Emerging Infectious Diseases Aug 2023Nontuberculous mycobacteria (NTM) infections are caused by environmental exposure. We describe spatial distribution of NTM infections and associations with... (Review)
Review
Nontuberculous mycobacteria (NTM) infections are caused by environmental exposure. We describe spatial distribution of NTM infections and associations with sociodemographic factors and flooding in Missouri, USA. Our retrospective analysis of mycobacterial cultures reported to the Missouri Department of Health and Social Services surveillance system during January 1, 2008-December 31, 2019, detected geographic clusters of infection. Multilevel Poisson regression quantified small-area geographic variations and identified characteristics associated with risk for infection. Median county-level NTM infection rate was 66.33 (interquartile range 51-91)/100,000 persons. Risk of clustering was significantly higher in rural areas (rate ratio 2.82, 95% CI 1.90-4.19) and in counties with >5 floodings per year versus no flooding (rate ratio 1.38, 95% CI 1.26-1.52). Higher risk for NTM infection was associated with older age, rurality, and more flooding. Clinicians and public health professionals should be aware of increased risk for NTM infections, especially in similar environments.
Topics: Humans; Missouri; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Prevalence; Retrospective Studies; Risk Factors; Age Factors; Floods; Rural Population; Male; Female; Middle Aged; Aged; Disease Hotspot
PubMed: 37486160
DOI: 10.3201/eid2908.230378 -
Frontiers in Public Health 2023Metagenomic next-generation sequencing (mNGS) has been gradually applied to the diagnosis of tuberculosis (TB) due to its rapid and highly sensitive characteristics.... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Metagenomic next-generation sequencing (mNGS) has been gradually applied to the diagnosis of tuberculosis (TB) due to its rapid and highly sensitive characteristics. Despite numerous studies on this subject, their results vary significantly. Thus, the current meta-analysis was performed to assess the performance of the mNGS on tuberculosis.
METHODS
PubMed, Embase, Web of Science, and The Cochrane Library were searched up to June 21, 2023. Studies utilizing the mNGS for tuberculosis detection were included. The risk of bias was assessed by QUADAS-2, and a meta-analysis was performed with STATA14.0 software.
RESULTS
Seventeen studies comprising 3,205 specimens were included. The combined sensitivity and specificity of mNGS for clinical specimens were 0.69[0.58-0.79] and 1.00[0.99-1.00], respectively. Subgroup analysis identified sequencing platform, diagnostic criteria, study type, sample size, and sample types as potential sources of heterogeneity. Cerebrospinal Fluid (CSF) has a lower sensitivity of 0.58 (0.39-0.75). In a population with a 10% prevalence rate, the accuracy of sensitivity reached 94%.
CONCLUSION
Metagenomic next-generation sequencing technology exhibits high sensitivity and speed in diagnosing . Its application in mono and mixed infections peoples shows promise, and mNGS is likely to be increasingly used to address challenges posed by complexes in the future.
Topics: Humans; Mycobacterium tuberculosis; High-Throughput Nucleotide Sequencing; Coinfection; Research Design; Technology
PubMed: 37637815
DOI: 10.3389/fpubh.2023.1224993 -
Frontiers in Immunology 2023Tuberculosis (TB) remains a significant global health challenge, claiming the lives of up to 1.5 million individuals annually. TB is caused by the human pathogen (Mtb),... (Review)
Review
Tuberculosis (TB) remains a significant global health challenge, claiming the lives of up to 1.5 million individuals annually. TB is caused by the human pathogen (Mtb), which primarily infects innate immune cells in the lungs. These immune cells play a critical role in the host defense against Mtb infection, influencing the inflammatory environment in the lungs, and facilitating the development of adaptive immunity. However, Mtb exploits and manipulates innate immune cells, using them as favorable niche for replication. Unfortunately, our understanding of the early interactions between Mtb and innate effector cells remains limited. This review underscores the interactions between Mtb and various innate immune cells, such as macrophages, dendritic cells, granulocytes, NK cells, innate lymphocytes-iNKT and ILCs. In addition, the contribution of alveolar epithelial cell and endothelial cells that constitutes the mucosal barrier in TB immunity will be discussed. Gaining insights into the early cellular basis of immune reactions to Mtb infection is crucial for our understanding of Mtb resistance and disease tolerance mechanisms. We argue that a better understanding of the early host-pathogen interactions could inform on future vaccination approaches and devise intervention strategies.
Topics: Humans; Mycobacterium tuberculosis; Endothelial Cells; Immunity, Innate; Tuberculosis; Cell Communication
PubMed: 37965344
DOI: 10.3389/fimmu.2023.1260859 -
Current Opinion in Microbiology Jun 2024Members of the order Mycobacteriales are distinguished by a characteristic diderm cell envelope, setting them apart from other Actinobacteria species. In addition to the... (Review)
Review
Members of the order Mycobacteriales are distinguished by a characteristic diderm cell envelope, setting them apart from other Actinobacteria species. In addition to the conventional peptidoglycan cell wall, these organisms feature an extra polysaccharide polymer composed of arabinose and galactose, termed arabinogalactan. The nonreducing ends of arabinose are covalently linked to mycolic acids (MAs), forming the immobile inner leaflet of the highly hydrophobic MA membrane. The contiguous outer leaflet of the MA membrane comprises trehalose mycolates and various lipid species. Similar to all actinobacteria, Mycobacteriales exhibit apical growth, facilitated by a polar localized elongasome complex. A septal cell envelope synthesis machinery, the divisome, builds instead of the cell wall structures during cytokinesis. In recent years, a growing body of knowledge has emerged regarding the cell wall synthesizing complexes of Mycobacteriales., focusing particularly on three model species: Corynebacterium glutamicum, Mycobacterium smegmatis, and Mycobacterium tuberculosis.
Topics: Cell Wall; Mycolic Acids; Galactans; Peptidoglycan; Mycobacterium tuberculosis; Corynebacterium glutamicum; Mycobacterium smegmatis; Arabinose; Bacterial Proteins
PubMed: 38653035
DOI: 10.1016/j.mib.2024.102478 -
Proceedings of the National Academy of... Aug 2023Trehalose plays a crucial role in the survival and virulence of the deadly human pathogen (). The type I ATP-binding cassette (ABC) transporter LpqY-SugABC is the sole...
Trehalose plays a crucial role in the survival and virulence of the deadly human pathogen (). The type I ATP-binding cassette (ABC) transporter LpqY-SugABC is the sole pathway for trehalose to enter . The substrate-binding protein, LpqY, which forms a stable complex with the translocator SugABC, recognizes and captures trehalose and its analogues in the periplasmic space, but the precise molecular mechanism for this process is still not well understood. This study reports a 3.02-Å cryoelectron microscopy structure of trehalose-bound LpqY-SugABC in the pretranslocation state, a crystal structure of LpqY in a closed form with trehalose bound and five crystal structures of LpqY in complex with different trehalose analogues. These structures, accompanied by substrate-stimulated ATPase activity data, reveal how LpqY recognizes and binds trehalose and its analogues, and highlight the flexibility in the substrate binding pocket of LpqY. These data provide critical insights into the design of trehalose analogues that could serve as potential molecular probe tools or as anti-TB drugs.
Topics: Humans; Cryoelectron Microscopy; Mycobacterium tuberculosis; Trehalose; ATP-Binding Cassette Transporters; Molecular Probes
PubMed: 37603751
DOI: 10.1073/pnas.2307625120 -
Journal of Immunology (Baltimore, Md. :... Nov 2023Mycobacterium tuberculosis cell-wall glycolipids such as mannosylated lipoarabinomannan (ManLAM) can inhibit murine CD4+ T cells by blocking TCR signaling. This results...
Mycobacterium tuberculosis cell-wall glycolipids such as mannosylated lipoarabinomannan (ManLAM) can inhibit murine CD4+ T cells by blocking TCR signaling. This results in suppression of IL-2 production, reduced T cell proliferation, and induction of CD4+ T cell anergy. This study extended these findings to the interaction between primary human CD4+ T cells and macrophages infected by mycobacteria. Exposure of human CD4+ T cells to ManLAM before activation resulted in loss of polyfunctionality, as measured by IL-2, IFN-γ, and TNF-α expression, and reduced CD25 expression. This was not associated with upregulation of inhibitory receptors CTLA-4, PD-1, TIM-3, and Lag-3. By confocal microscopy and imaging flow cytometry, ManLAM exposure reduced conjugate formation between macrophages and CD4+ T cells. ManLAM colocalized to the immunological synapse (IS) and reduced translocation of lymphocyte-specific protein tyrosine kinase (LCK) to the IS. When CD4+ T cells and Mycobacterium bovis BCG-infected monocytes were cocultured, ManLAM colocalized to CD4+ T cells, which formed fewer conjugates with infected monocytes. These results demonstrate that mycobacterial cell-wall glycolipids such as ManLAM can traffic from infected macrophages to disrupt productive IS formation and inhibit CD4+ T cell activation, contributing to immune evasion by M. tuberculosis.
Topics: Humans; CD4-Positive T-Lymphocytes; Glycolipids; Immunological Synapses; Interleukin-2; Macrophages; Mycobacterium tuberculosis
PubMed: 37695687
DOI: 10.4049/jimmunol.2300107 -
Nature Communications Sep 2023The cell walls of pathogenic and acidophilic bacteria, such as Mycobacterium tuberculosis and Mycobacterium leprae, contain lipoarabinomannan and arabinogalactan. These...
The cell walls of pathogenic and acidophilic bacteria, such as Mycobacterium tuberculosis and Mycobacterium leprae, contain lipoarabinomannan and arabinogalactan. These components are composed of D-arabinose, the enantiomer of the typical L-arabinose found in plants. The unique glycan structures of mycobacteria contribute to their ability to evade mammalian immune responses. In this study, we identified four enzymes (two GH183 endo-D-arabinanases, GH172 exo-α-D-arabinofuranosidase, and GH116 exo-β-D-arabinofuranosidase) from Microbacterium arabinogalactanolyticum. These enzymes completely degraded the complex D-arabinan core structure of lipoarabinomannan and arabinogalactan in a concerted manner. Furthermore, through biochemical characterization using synthetic substrates and X-ray crystallography, we elucidated the mechanisms of substrate recognition and anomer-retaining hydrolysis for the α- and β-D-arabinofuranosidic bonds in both endo- and exo-mode reactions. The discovery of these D-arabinan-degrading enzymes, along with the understanding of their structural basis for substrate specificity, provides valuable resources for investigating the intricate glycan architecture of mycobacterial cell wall polysaccharides and their contribution to pathogenicity.
Topics: Animals; Female; Humans; Galactans; Lipopolysaccharides; Mycobacterium tuberculosis; Endometriosis; Mammals
PubMed: 37726269
DOI: 10.1038/s41467-023-41431-2 -
MBio Jan 2024As we rapidly approach a post-antibiotic era, bacteriophage (phage) therapy may offer a solution for treating drug-resistant bacteria. is an emerging,...
As we rapidly approach a post-antibiotic era, bacteriophage (phage) therapy may offer a solution for treating drug-resistant bacteria. is an emerging, multidrug-resistant pathogen that causes disease in people with cystic fibrosis, chronic obstructive pulmonary disease, and other underlying lung diseases. can survive inside host cells, a niche that can limit access to antibiotics. As current treatment options for infections often fail, there is an urgent need for alternative therapies. Phage therapy is being used to treat infections as an option of last resort. However, little is known about the ability of phages to kill bacteria in the host environment and specifically in an intracellular environment. Here, we demonstrate the ability of phages to enter mammalian cells and to infect and kill intracellular . These findings support the use of phages to treat intracellular bacterial pathogens.
Topics: Animals; Humans; Mycobacterium abscessus; Bacteriophages; Cystic Fibrosis; Anti-Bacterial Agents; Mammals
PubMed: 38059609
DOI: 10.1128/mbio.02924-23 -
ACS Infectious Diseases Feb 2024In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic... (Review)
Review
In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic nontuberculous mycobacteria (NTM). Among these, two neglected mycobacteria species of the Acinetobacter family, and , are the etiological agents of leprosy and Buruli ulcer infections, respectively, and fall under the broad umbrella of neglected tropical diseases (NTDs). Unfortunately, lackluster drug discovery efforts have been made against these pathogenic bacteria in the recent decade, resulting in the discovery of only a few countable hits and majorly repurposing anti-TB drug candidates such as telacebec (Q203), P218, and TB47 for current therapeutic interventions. Major ignorance in drug candidate identification might aggravate the dramatic consequences of rapidly spreading mycobacterial NTDs in the coming days. Therefore, this Review focuses on an up-to-date account of drug discovery efforts targeting selected druggable targets from both bacilli, including the accompanying challenges that have been identified and are responsible for the slow drug discovery. Furthermore, a succinct discussion of the all-new possibilities that could be alternative solutions to mitigate the neglected mycobacterial NTD burden and subsequently accelerate the drug discovery effort is also included. We anticipate that the state-of-the-art strategies discussed here may attract major attention from the scientific community to navigate and expand the roadmap for the discovery of next-generation therapeutics against these NTDs.
Topics: Humans; Mycobacterium ulcerans; Mycobacterium leprae; Buruli Ulcer; Mycobacterium
PubMed: 38295025
DOI: 10.1021/acsinfecdis.3c00371