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Emerging Microbes & Infections Dec 2024The discovery of promising cytokines and clarification of their immunological mechanisms in controlling the intracellular fate of (Mtb) are necessary to identify...
The discovery of promising cytokines and clarification of their immunological mechanisms in controlling the intracellular fate of (Mtb) are necessary to identify effective diagnostic biomarkers and therapeutic targets. To escape immune clearance, Mtb can manipulate and inhibit the normal host process of phagosome maturation. Phagosome maturation arrest by Mtb involves multiple effectors and much remains unknown about this important aspect of Mtb pathogenesis. In this study, we found that interleukin 16 (IL-16) is elevated in the serum samples of Tuberculosis (TB) patients and can serve as a specific target for treatment TB. There was a significant difference in IL-16 levels among active TB, latent TB infection (LTBI), and non-TB patients. This study first revealed that macrophages are the major source of IL-16 production in response to Mtb infection, and elucidated that IL-16 can promote Mtb intracellular survival by inhibiting phagosome maturation and suppressing the expression of Rev-erbα which can inhibit IL-10 secretion. The experiments using zebrafish larvae infected with and mice challenged with H37Rv demonstrated that reducing IL-16 levels resulted in less severe pathology and improved survival, respectively. In conclusion, this study provided direct evidence that Mtb hijacks the host macrophages-derived interleukin 16 to enhance intracellular growth. It is suggesting the immunosuppressive role of IL-16 during Mtb infection, supporting IL-16 as a promising therapeutic target.
Topics: Animals; Humans; Mice; Interleukin-16; Macrophages; Mycobacterium tuberculosis; Phagosomes; Tuberculosis; Zebrafish
PubMed: 38380651
DOI: 10.1080/22221751.2024.2322663 -
Life Science Alliance Apr 2024Regulation of host miRNA expression is a contested node that controls the host immune response to mycobacterial infection. The host must counter subversive efforts of...
Regulation of host miRNA expression is a contested node that controls the host immune response to mycobacterial infection. The host must counter subversive efforts of pathogenic mycobacteria to launch a protective immune response. Here, we examine the role of miR-126 in the zebrafish- infection model and identify a protective role for infection-induced miR-126 through multiple effector pathways. We identified a putative link between miR-126 and the and signalling axes resulting in the suppression of non- expressing macrophage accumulation at early granulomas. Mechanistically, we found a detrimental effect of expression that renders zebrafish embryos susceptible to higher bacterial burden and increased cell death via mTOR inhibition. We found that macrophage recruitment driven by the signalling axis was at the expense of the recruitment of classically activated -expressing macrophages and increased cell death around granulomas. Together, our results delineate putative pathways by which infection-induced miR-126 may shape an effective immune response to infection in zebrafish embryos.
Topics: Animals; Granuloma; Macrophages; MicroRNAs; Mycobacterium Infections, Nontuberculous; Zebrafish; Tuberous Sclerosis Complex 1 Protein; Chemokine CXCL12; Zebrafish Proteins
PubMed: 38307625
DOI: 10.26508/lsa.202302523 -
MSystems Feb 2024Tuberculosis remains the most pervasive infectious disease and the recent emergence of drug-resistant strains emphasizes the need for more efficient drug treatments. A...
Tuberculosis remains the most pervasive infectious disease and the recent emergence of drug-resistant strains emphasizes the need for more efficient drug treatments. A key feature of pathogenesis, conserved between the human pathogen and the model pathogen is the metabolic switch to lipid catabolism and altered expression of virulence genes at different stages of infection. This study aims to identify genes involved in sustaining viable intracellular infection. We applied transposon sequencing (Tn-Seq) to , an unbiased genome-wide strategy combining saturation insertional mutagenesis and high-throughput sequencing. This approach allowed us to identify the localization and relative abundance of insertions in pools of transposon mutants. Gene essentiality and fitness cost of mutations were quantitatively compared between growth and different stages of infection in two evolutionary distinct phagocytes, the amoeba and the murine BV2 microglial cells. In the genome, 57% of TA sites were disrupted and 568 genes (10.2%) were essential, which is comparable to previous Tn-Seq studies on and . Major pathways involved in the survival of during infection of are related to DNA damage repair, lipid and vitamin metabolism, the type VII secretion system (T7SS) ESX-1, and the Mce1 lipid transport system. These pathways, except Mce1 and some glycolytic enzymes, were similarly affected in BV2 cells. These differences suggest subtly distinct nutrient availability or requirement in different host cells despite the known predominant use of lipids in both amoeba and microglial cells.IMPORTANCEThe emergence of biochemically and genetically tractable host model organisms for infection studies holds the promise to accelerate the pace of discoveries related to the evolution of innate immunity and the dissection of conserved mechanisms of cell-autonomous defenses. Here, we have used the genetically and biochemically tractable infection model system / to apply a genome-wide transposon-sequencing experimental strategy to reveal comprehensively which mutations confer a fitness advantage or disadvantage during infection and compare these to a similar experiment performed using the murine microglial BV2 cells as host for to identify conservation of virulence pathways between hosts.
Topics: Animals; Mice; Humans; Virulence; Microglia; Mycobacterium marinum; Amoeba; Dictyostelium; Tuberculosis; Mycobacterium tuberculosis; Lipids
PubMed: 38270456
DOI: 10.1128/msystems.01326-23 -
Journal of Biotechnology Feb 2024Mycobacterium marinum CAR (MmCAR) is one of the most widely used CARs as the key enzyme for the synthesis of aldehydes, alcohols and further products from the respective...
Mycobacterium marinum CAR (MmCAR) is one of the most widely used CARs as the key enzyme for the synthesis of aldehydes, alcohols and further products from the respective carboxylic acids. Herein, we describe the first functionally secreted 131 kDa CAR and its isolated A-domain using Komagataella phaffii and a methanol-free constitutive expression strategy. Precipitated and lyophilized MmCAR (500 µg) was isolated from the culture supernatant and showed no decrease in activity for piperonylic acid (80% conversion), even when stored for up to 3 weeks at 4°C. Lyophilized MmCAR precipitate gave 48% yield of E/Z-nonanal-4-nitrobenzoyloxime from the reduction of nonanoic acid and in-situ derivatization with O-4-nitrobenzoyl-hydroxylamine. Furthermore, K. phaffii could successfully secrete the MmCAR adenylation domain. Its activity was confirmed by the amidation of benzoic acid with n-hexylamine. Neither enzyme variant was glycosylated by the yeast. In summary, functional CAR can be secreted by K. phaffii and used for cell free conversion of carboxylic acids to various products.
Topics: Carboxylic Acids; Oxidoreductases; Alcohols
PubMed: 38266924
DOI: 10.1016/j.jbiotec.2024.01.008 -
Frontiers in Cellular and Infection... 2023Anti-bacterial autophagy, also known as xenophagy, is a crucial innate immune process that helps maintain cellular homeostasis by targeting invading microbes. This...
Anti-bacterial autophagy, also known as xenophagy, is a crucial innate immune process that helps maintain cellular homeostasis by targeting invading microbes. This defense pathway is widely studied in the context of infections with mycobacteria, the causative agents of human tuberculosis and tuberculosis-like disease in animal models. Our previous work in a zebrafish tuberculosis model showed that host defense against (Mm) is impaired by deficiencies in xenophagy receptors, optineurin (Optn) or sequestome 1 (p62), and Damage-regulated autophagy modulator 1 (Dram1). However, the interdependency of these receptors and their interaction with Dram1 remained unknown. In the present study, we used single and double knockout zebrafish lines in combination with overexpression experiments. We show that Optn and p62 can compensate for the loss of each other's function, as their overexpression restores the infection susceptibility of the mutant phenotypes. Similarly, Dram1 can compensate for deficiencies in Optn and p62, and, vice versa, Optn and p62 compensate for the loss of Dram1, indicating that these xenophagy receptors and Dram1 do not rely on each other for host defense against Mm. In agreement, Dram1 overexpression in double mutants restored the interaction of autophagosome marker Lc3 with Mm. Finally, double mutants displayed more severe infection susceptibility than the single mutants. Taken together, these results suggest that Optn and p62 do not function downstream of each other in the anti-mycobacterial xenophagy pathway, and that the Dram1-mediated defense against Mm infection does not rely on specific xenophagy receptors.
Topics: Animals; Autophagy; Macroautophagy; Mycobacterium marinum; Tuberculosis; Zebrafish; Zebrafish Proteins
PubMed: 38264729
DOI: 10.3389/fcimb.2023.1331818 -
BioRxiv : the Preprint Server For... Jan 2024The mycobacterial cell envelope is a major virulence determinant in pathogenic mycobacteria. Specific outer lipids play roles in pathogenesis, modulating the immune...
The mycobacterial cell envelope is a major virulence determinant in pathogenic mycobacteria. Specific outer lipids play roles in pathogenesis, modulating the immune system and promoting the secretion of virulence factors. ESX-1 (ESAT-6 system-1) is a conserved protein secretion system required for mycobacterial pathogenesis (1, 2). Previous studies revealed that mycobacterial strains lacking the outer lipid PDIM have impaired ESX-1 function during laboratory growth and infection (3-5). The mechanisms underlying changes in ESX-1 function are unknown. We used a proteo-genetic approach to measure PDIM and PGL-dependent protein secretion in , a non-tubercular mycobacterial pathogen that causes tuberculosis-like disease in ectothermic animals (6, 7). Importantly, is a well-established model for mycobacterial pathogenesis (8, 9). Our findings showed that strains without PDIM and PGL showed specific, significant reductions in protein secretion compared to the WT and complemented strains. We recently established a hierarchy for the secretion of ESX-1 substrates in four (I-IV) groups (10). Loss of PDIM differentially impacted secretion of Groups III and IV ESX-1 substrates, which are likely the effectors of pathogenesis. Our data suggests that the altered secretion of specific ESX-1 substrates is responsible for the observed ESX-1-related effects in PDIM-deficient strains.
PubMed: 38260599
DOI: 10.1101/2024.01.09.574891 -
Computational and Structural... Dec 2024The exposure of ethanol increases the risk of head and neck inflammation and tumor progression. However, limited studies have investigated the composition and...
UNLABELLED
The exposure of ethanol increases the risk of head and neck inflammation and tumor progression. However, limited studies have investigated the composition and functionality of laryngeal microbiota under ethanol exposure. We established an ethanol-exposed mouse model to investigate the changes in composition and function of laryngeal microbiota using Metagenomic shotgun sequencing. In the middle and late stages of the experiment, the laryngeal microbiota of mice exposed to ethanol exhibited obvious distinguished from that of the control group on principal-coordinate analysis (PCoA) plots. Among the highly abundant species, and were likely to be most impacted. Our findings indicated that the exposure to ethanol significantly increased their abundance in larynxes in mice of the same age, which has been confirmed through FISH experiments. Among the species-related functions and genes, metabolism is most severely affected by ethanol. The difference was most obvious in the second month of the experiment, which may be alleviated later because the animal established tolerance. Notable enrichments concerning energy, amino acid, and carbohydrate metabolic pathways occurred during the second month under ethanol exposure. Finally, based on the correlation between species and functional variations, a network was established to investigate relationships among microbiota, functional pathways, and related genes affected by ethanol. Our data first demonstrated the continuous changes of abundance, function and their interrelationship of laryngeal microbiota under ethanol exposure by Metagenomic shotgun sequencing.
IMPORTANCE
Ethanol may participate in the inflammation and tumor progression by affecting the composition of the laryngeal microbiota. Here, we applied the metagenomic shotgun sequencing instead of 16 S rRNA sequencing method to identify the laryngeal microbiota under ethanol exposure. and are two dominant species that may play a role in the reconstruction of the laryngeal microenvironment, as their local abundance increases following exposure to ethanol. The metabolic function is most evidently impacted, and several potential metabolic pathways could be associated with alterations in microbiota composition. These findings could help us better understand the impact of prolonged ethanol exposure on the microbial composition and functionality in the larynx.
PubMed: 38235358
DOI: 10.1016/j.csbj.2023.12.022 -
Vaccine Jan 2024Based on previous evidence demonstrating the efficacy of inactivated mycobacteria for the control of fish mycobacteriosis, we explored the protective efficacy of two...
Based on previous evidence demonstrating the efficacy of inactivated mycobacteria for the control of fish mycobacteriosis, we explored the protective efficacy of two inactivated Mycobacterium bovis administered via parenteral and mucosal routes against Mycobacterium marinum infection mimicking natural conditions in the zebrafish model of tuberculosis. Although we did not observe a clear effect of any of the immunostimulants on mycobacterial burden, the results showed a significant increase in TLR2 and TLR4 gene expression levels in fishes parenterally immunized with inactivated Bacillus Calmette-Guérin (BCG). Our findings demonstrated that the TLR2 and the TLR4 signaling pathways are involved in the immune response elicited by inactivated mycobacteria in the zebrafish model of tuberculosis and support the use of inactivated mycobacteria in vaccine formulations for the control of mycobacteriosis.
Topics: Animals; Toll-Like Receptor 2; Zebrafish; Toll-Like Receptor 4; Hot Temperature; Tuberculosis; Mycobacterium bovis; BCG Vaccine
PubMed: 38184390
DOI: 10.1016/j.vaccine.2023.12.085 -
Photodiagnosis and Photodynamic Therapy Feb 2024
PubMed: 38118372
DOI: 10.1016/j.pdpdt.2023.103909 -
Heliyon Nov 2023A series of triclosan azo-adducts were synthesized to investigate their structure-activity relationship against and non-tuberculous mycobacteria. The series' most...
A series of triclosan azo-adducts were synthesized to investigate their structure-activity relationship against and non-tuberculous mycobacteria. The series' most potent compound was four and sixteen times more active than triclosan and rifabutin against drug-resistant , respectively, while being less cytotoxic to human macrophages than triclosan on day one. Additionally, one of the azo-adducts was twice as efficient against as triclosan and twice as effective against as isoniazid. Furthermore, the synthesized azo-adducts were equally effective against strains overexpressing InhA, suggesting that these compounds work through a distinct mechanism.
PubMed: 38034623
DOI: 10.1016/j.heliyon.2023.e22182