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Journal of Thoracic Disease Aug 2023As the first line of defense, epithelial cells play a vital role in the initiation and control of both innate and adaptive immunity, which participate in the development...
BACKGROUND
As the first line of defense, epithelial cells play a vital role in the initiation and control of both innate and adaptive immunity, which participate in the development of disease. Despite its therapeutic significance, little is understood about the specific interaction between pathogenic microorganisms and lung epithelial cells.
METHODS
In this study, we performed a head-to-head comparison of the virulence and infection mechanisms of () and (), which represent Gram-negative/positive respiratory pathogens, respectively, in lung epithelial cell models for the first time.
RESULTS
Through scanning electron microscopy combined with bacterial infection experiments, we confirmed the ability of and strains to form biofilm and cord factor out of the cell wall. has stronger adhesion and intracellular retention ability, while is more likely to induce acute infection. These pathogens could stay and proliferate in lung epithelial cells and stimulate the secretion of specific cytokines and chemokines through a gene transcription regulator. infection can promote crosstalk among epithelial cells and other immune cells in the lung from a very early stage by prompting the secretion of pro-inflammatory cytokines. Meanwhile, there were significant correlations between infection and higher levels of interleukin-15 (IL-15), interleukin-1Rα (IL-1Rα), fibroblast growth factor (FGF) basic, and granulocyte colony-stimulating factor (G-CSF). At the same time, infection also led to changes in the expression of cytoskeletal proteins in epithelial cells.
CONCLUSIONS
Our results emphasized the immunoprotection and immunomodulation of lung epithelial cells against exogenous pathogenic microorganisms, indicating that different pathogens damaged the host through different strategies and induced varying innate immune responses. At the same time, they provided important clues and key immune factors for dealing with complicated pulmonary infections.
PubMed: 37691650
DOI: 10.21037/jtd-23-493 -
Cell Reports Dec 2021Although prokaryotic organisms lack traditional organelles, they must still organize cellular structures in space and time, challenges that different species solve...
Although prokaryotic organisms lack traditional organelles, they must still organize cellular structures in space and time, challenges that different species solve differently. To systematically define the subcellular architecture of mycobacteria, we perform high-throughput imaging of a library of fluorescently tagged proteins expressed in Mycobacterium smegmatis and develop a customized computational pipeline, MOMIA and GEMATRIA, to analyze these data. Our results establish a spatial organization network of over 700 conserved mycobacterial proteins and reveal a coherent localization pattern for many proteins of known function, including those in translation, energy metabolism, cell growth and division, as well as proteins of unknown function. Furthermore, our pipeline exploits morphologic proxies to enable a pseudo-temporal approximation of protein localization and identifies previously uncharacterized cell-cycle-dependent dynamics of essential mycobacterial proteins. Collectively, these data provide a systems perspective on the subcellular organization of mycobacteria and provide tools for the analysis of bacteria with non-standard growth characteristics.
Topics: Bacterial Proteins; Cell Cycle; Molecular Imaging; Mycobacterium smegmatis; Organelles; Protein Transport; Spatio-Temporal Analysis
PubMed: 34965429
DOI: 10.1016/j.celrep.2021.110154 -
Human Vaccines & Immunotherapeutics Dec 2023The immune escape mutations of SARS-CoV-2 variants emerged frequently, posing a new challenge to weaken the protective efficacy of current vaccines. Thus, the...
The immune escape mutations of SARS-CoV-2 variants emerged frequently, posing a new challenge to weaken the protective efficacy of current vaccines. Thus, the development of novel SARS-CoV-2 vaccines is of great significance for future epidemic prevention and control. We herein reported constructing the attenuated () as a bacterial surface display system to carry the spike (S) and nucleocapsid (N) of SARS-CoV-2. To mimic the native localization on the surface of viral particles, the S or N antigen was fused with truncated PE_PGRS33 protein, which is a transportation component onto the cell wall of (). The sub-cellular fraction analysis demonstrated that S or N protein was exactly expressed onto the surface (cell wall) of the recombinant . After the immunization of the -based COVID-19 vaccine candidate in mice, S or N antigen-specific T cell immune responses were effectively elicited, and the subsets of central memory CD4+ T cells and CD8+ T cells were significantly induced. Further analysis showed that there were some potential cross-reactive CTL epitopes between SARS-CoV-2 and . Overall, our data provided insights that -based bacterial surface display system could be a suitable vector for developing T cell-based vaccines against SARS-CoV-2 and other infectious diseases.
Topics: Mice; Humans; Animals; Mycobacterium smegmatis; COVID-19 Vaccines; COVID-19; SARS-CoV-2; Spike Glycoprotein, Coronavirus
PubMed: 36785935
DOI: 10.1080/21645515.2023.2171233 -
Respiration; International Review of... 2022Rates of antimicrobial resistance are increasing globally while the pipeline of new antibiotics is drying up, putting patients with disease caused by drug-resistant... (Review)
Review
Rates of antimicrobial resistance are increasing globally while the pipeline of new antibiotics is drying up, putting patients with disease caused by drug-resistant bacteria at increased risk of complications and death. The growing costs for diagnosis and management of drug resistance threaten tuberculosis control where the disease is endemic and resources limited. Bacteriophages are viruses that attack bacteria. Phage preparations served as anti-infective agents long before antibiotics were discovered. Though small in size, phages are the most abundant and diverse biological entity on earth. Phages have co-evolved with their hosts and possess all the tools needed to infect and kill bacteria, independent of drug resistance. Modern biotechnology has improved our understanding of the biology of phages and their possible uses. Phage preparations are available to treat meat, fruit, vegetables, and dairy products against parasites or to prevent contamination with human pathogens, such as Listeria monocytogenes, Escherichia coli, or Staphylococcus aureus. Such phage-treated products are considered fit for human consumption. A number of recent case reports describe in great detail the successful treatment of highly drug-resistant infections with individualized phage preparations. Formal clinical trials with standardized products are slowly emerging. With its highly conserved genome and relative paucity of natural phage defence mechanisms Mycobacterium tuberculosis appears to be a suitable target for phage treatment. A phage cocktail with diverse and strictly lytic phages that kill all lineages of M. tuberculosis, and can be propagated on Mycobacterium smegmatis, has been assembled and is available for the evaluation of optimal dosage and suitable routes of administration for tuberculosis in humans. Phage treatment can be expected to be safe and active on extracellular organisms, but phage penetration to intracellular and granulomatous environments as well as synergistic effects with antibiotics are important questions to address during further evaluation.
Topics: Anti-Bacterial Agents; Bacteriophages; Delusions; Humans; Mycobacteriophages; Mycobacterium tuberculosis; Tuberculosis
PubMed: 34814151
DOI: 10.1159/000519870 -
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... Apr 2021Encapsulins containing dye-decolorizing peroxidase (DyP)-type peroxidases are ubiquitous among prokaryotes, protecting cells against oxidative stress. However, little is...
Encapsulins containing dye-decolorizing peroxidase (DyP)-type peroxidases are ubiquitous among prokaryotes, protecting cells against oxidative stress. However, little is known about how they interact and function. Here, we have isolated a native cargo-packaging encapsulin from and determined its complete high-resolution structure by cryogenic electron microscopy (cryo-EM). This encapsulin comprises an icosahedral shell and a dodecameric DyP cargo. The dodecameric DyP consists of two hexamers with a twofold axis of symmetry and stretches across the interior of the encapsulin. Our results reveal that the encapsulin shell plays a role in stabilizing the dodecameric DyP. Furthermore, we have proposed a potential mechanism for removing the hydrogen peroxide based on the structural features. Our study also suggests that the DyP is the primary cargo protein of mycobacterial encapsulins and is a potential target for antituberculosis drug discovery.
Topics: Bacterial Proteins; Cryoelectron Microscopy; Mycobacterium smegmatis; Organelles; Peroxidases
PubMed: 33853951
DOI: 10.1073/pnas.2025658118 -
Nature Communications Sep 2023Tuberculosis continues to pose a serious threat to global health. Mycobacterium tuberculosis, the causative agent of tuberculosis, is an intracellular pathogen that...
Tuberculosis continues to pose a serious threat to global health. Mycobacterium tuberculosis, the causative agent of tuberculosis, is an intracellular pathogen that relies on various mechanisms to survive and persist within the host. Among their many virulence factors, mycobacteria encode Mce systems. Some of these systems are implicated in lipid uptake, but the molecular basis for Mce function(s) is poorly understood. To gain insights into the composition and architecture of Mce systems, we characterized the putative Mce1 complex involved in fatty acid transport. We show that the Mce1 system in Mycobacterium smegmatis comprises a canonical ATP-binding cassette transporter associated with distinct heterohexameric assemblies of substrate-binding proteins. Furthermore, we establish that the conserved membrane protein Mce1N negatively regulates Mce1 function via a unique mechanism involving blocking transporter assembly. Our work offers a molecular understanding of Mce complexes, sheds light on mycobacterial lipid metabolism and its regulation, and informs future anti-mycobacterial strategies.
Topics: Membrane Proteins; Mycobacterium smegmatis; Mycobacterium tuberculosis; Membrane Transport Proteins; ATP-Binding Cassette Transporters
PubMed: 37736771
DOI: 10.1038/s41467-023-41578-y -
Microbiology Resource Announcements Oct 2022IgnatiusPatJac is a mycobacteriophage capable of lytic infection in Mycobacterium smegmatis and Mycobacterium tuberculosis. It was isolated from damp soil in...
IgnatiusPatJac is a mycobacteriophage capable of lytic infection in Mycobacterium smegmatis and Mycobacterium tuberculosis. It was isolated from damp soil in Johannesburg, South Africa. The 51,164-bp double-stranded DNA genome has a GC content of 63.6%, predicted to encode 93 genes. IgnatiusPatJac is classified as an A1 subcluster mycobacteriophage.
PubMed: 36129274
DOI: 10.1128/mra.00664-22 -
Microbiology (Reading, England) Feb 2021Multi-subunit SMC complexes are required to perform essential functions, such as chromosome compaction, segregation and DNA repair, from bacteria to humans. Prokaryotic...
Multi-subunit SMC complexes are required to perform essential functions, such as chromosome compaction, segregation and DNA repair, from bacteria to humans. Prokaryotic SMC proteins form complexes with two non-SMC subunits, ScpA and ScpB, to condense the chromosome. The mutants of both and genes in have been shown to display characteristic phenotypes such as growth defects and increased frequency of anucleate cells. Here, we studied the function of the Smc-ScpAB complex from . We observed no significant growth difference between the null mutant and wild-type under both standard and stress conditions. Furthermore, we characterized the Smc-ScpAB holocomplex from . The MsSMC consists of the dimerization hinge and ATPase head domains connected by long coiled-coils. The MsSMC interacts with two non-SMC proteins, ScpA and ScpB, and the resulting holocomplex binds to different DNA substrates independent of ATP. The Smc-ScpAB complex showed DNA-stimulated ATPase activity in the presence of ssDNA. A cytological profiling assay revealed that upon overexpression the Smc-ScpAB ternary complex compacts the decondensed nucleoid of rifampicin-treated wild-type and null mutant of . Together, our study suggests that has a functional Smc-ScpAB complex capable of DNA binding and condensation. Based on our observations, we speculate that the presence of alternative SMCs such as MksB or other SMC homologues might have rescued the mutant phenotype in .
Topics: Adenosine Triphosphatases; Bacterial Proteins; Cell Cycle Proteins; Chromosomes, Bacterial; DNA, Bacterial; DNA-Binding Proteins; Multiprotein Complexes; Mutation; Mycobacterium smegmatis; Protein Binding; Protein Domains; Protein Multimerization
PubMed: 33350902
DOI: 10.1099/mic.0.001011 -
Journal of Infection and Public Health Sep 2020An alternate host for mycobacteria is Mycobacterium smegmatis which is used frequently. It is a directly budding eco-friendly organism not emulated as human infection.... (Review)
Review
An alternate host for mycobacteria is Mycobacterium smegmatis which is used frequently. It is a directly budding eco-friendly organism not emulated as human infection. It is mainly useful for the investigation of various microorganisms in the sort of Mycobacteria in cell culture laboratories. Some Mycobacterium species groups that is normal, unsafe ailments, likely to Mycobacterium leprae, Mycobacterium tuberculosis and Mycobacterium bovis. At present, various laboratories are clean and culture this type of species to make an opinion that fascinating route of harmful Mycobacteria. This publication provides aggregate data on cell shape, genome studies, ecology, pathology and utilization of M. smegmatis.
Topics: Bacterial Proteins; Humans; Liposomes; Models, Biological; Mycobacterium Infections, Nontuberculous; Mycobacterium smegmatis; Mycobacterium tuberculosis
PubMed: 32674978
DOI: 10.1016/j.jiph.2020.06.023