Project description:We report the transcriptome of M. abscessus in amoebae and macrophages. M. abscessus intra-amoebal and intra-macrophagic transcriptomes demonstrate of the potential of M. abscessus to adapt to an intracellular lifestyle, though amoebae largely contribute to the enhancement of M. abscessus survival macrophages.
Project description:Tuberculosis (TB) is still a major global health challenge, killing over 1.5 million people each year, and hence, there is a need to identify and develop novel treatments for Mycobacterium tuberculosis (M. tuberculosis). The prevalence of infections caused by nontuberculous mycobacteria (NTM) is also increasing and has overtaken TB cases in the United States and much of the developed world. Mycobacterium abscessus (M. abscessus) is one of the most frequently encountered NTM and is difficult to treat. We describe the use of drug-disease association using a semantic knowledge graph approach combined with machine learning models that has enabled the identification of several molecules for testing anti-mycobacterial activity. We established that niclosamide (M. tuberculosis IC90 2.95 μM; M. abscessus IC90 59.1 μM) and tribromsalan (M. tuberculosis IC90 76.92 μM; M. abscessus IC90 147.4 μM) inhibit M. tuberculosis and M. abscessus in vitro. To investigate the mode of action, we determined the transcriptional response of M. tuberculosis and M. abscessus to both compounds in axenic log phase, demonstrating a broad effect on gene expression that differed from known M. tuberculosis inhibitors. Both compounds elicited transcriptional responses indicative of respiratory pathway stress and the dysregulation of fatty acid metabolism. Further testing against drug-resistant isolates and other NTM is warranted to clarify the usefulness of these repurposed drugs for mycobacteria.
Project description:Mice were challneged with Mycobacterium abscessus cell wall particles intra- tracheally or saline. Lung was harvested after 3 weeks. RNA extracted from lungs and RNASeq was performed to identify differentially expressed genes.
Project description:Human macrophages are a natural host of many mycobacterium species, including Mycobacterium abscessus (M. abscessus), an emerging pathogen affecting patients with lung diseases and immunocompromised individuals. There are few available treatments and the search for effective antibiotics against M. abscessus has been hindered by the lack of a tractable in vitro intracellular model of infection. Here, we established a reliable model for M. abscessus infection using human pluripotent stem cell-derived macrophages (hPSC-macrophages). hPSC differentiation permitted a reproducible generation of functional human macrophages that were highly susceptible to M. abscessus infection. Electron microscopy demonstrated that M. abscessus was present in the vacuoles of hPSC-macrophages. RNA-sequencing analysis revealed a time dependent host cell response to M. abscessus, with differing gene and protein expression patterns observed at 3-hours, 24-hours and 48-hours post-infection. Culture of engineered tdTOMATO-expressing hPSC-macrophages with GFP-expressing M. abscessus enabled rapid and image-based high-throughput analysis of intracellular infection and quantitative assessment of antibiotic resistance and efficacy. Our study describes the first hPSC-based model for M. abscessus infection, which represents a novel platform for studying M. abscessus-host interaction and an accessible tool for drug discovery.
Project description:WT M. abscessus ATCC_19977 was used to construct a targeted deletion mutant lacking the sRNA B11 and a complemented version of the mutant with ectopic expression of B11 from its native promoter at the L5 site. The deletion mutant was also complemented with versions of B11 that lacked a single C from the first loop or had an extra C in the second loop. All strains were grown to log phase and the extracted RNA was used to perform expression profiling by RNAseq.
Project description:Bronchial Epithelial cells were exposed to microparticles generated from mycobacterium abscessus MAB cell wall per an in-house protocol. Control group was exposed to saline. Differentially expressed genes related to MAB cell wall particles were determined.
Project description:The response of human neutrophils to the emerging pathogen Mycobacterium abscessus has not been described. However, M. abscessus infections are frequently associated with neutrophil-rich abscesses. To better understand the reponse of neutrophils to M. abscessus we performed gene expression analysis using Affymetrix HG-U133A Plus 2.0 microarrays. Human neutrophils from healthy donors were stimulated with isogenic rough and smooth morphotypes of M. abscessus. Staphylococcus aureus was used as a control. Gene expression was compared to neutrophils left unstimulated. Neutrophils from four individual donors were isolated on separate days and stimulated with freshly prepared bacteria. Neutrophils (stimulated and control) were left for 2 hours before total RNA was isolated, and biotinylated cRNA was prepared by standard methods. Analysis indicates that M. abscessus morphotypes induce a limited number of genes, when compared to S. aureus, which are enriched in genes for cytokines and chemokines, including neutrophil-specific chemokines. These data suggest that neutrophils have a limited response to M. abscessus, which may contribute to neutrophil-rich abscess formation.!Series_overall_design = Human neutrophils from healthy donors were exposed to rough Mab (ATCC 19977T), smooth Mab (ATCC 19977T) and S. aureus (CF clinical strain) for two hours; control cells were exposed to saline.
Project description:Mycobacterium abscessus is nowadays under the spotlight of the scientific community. This pathogenic mycobacteria is indeed responsible for a wide spectrum of infections involving mostly pulmonary infections in patients with cystic fibrosis. M. abscessus is intrinsically resistant to a broad range of antibiotics, including most antitubercular drugs, and is considered the most pathogenic and chemotherapy-resistant rapidly growing mycobacterium. Consequently, with very limited treatment options, the development of new therapeutic approaches to fight this pathogen are urgently needed. 38 new analogs of Cyclipostins & Cyclophostin (CyC), compounds naturally produced by Streptomyces species, have been synthesized. Their antibacterial activities against clinical isolates belonging to the M. chelonae-abscessus clade, as well as Gram-negative and Gram-positive bacteria have been evaluated by the REMA method. The intracellular activities of the CyC against intramacrophagic M. abscessus have also been investigated and compared to those of imipenem. The CyCs displayed very low toxicity towards host cells and their inhibitory activity was exclusively restricted to mycobacteria. The best candidate, CyC17, showed a high selectivity for mycobacteria with MIC values (<2 up to 40 µg/mL) comparable to those of most classical antibiotics used to treat M. abscessus infections. Of importance, several CyCs were active against extracellular M. abscessus growth (i.e., CyC17 / CyC18β / CyC25 / CyC26) or against intracellular mycobacteria inside macrophages (i.e., CyC7α,β / CyC8α,β) with MIC values similar to or better than those of standard antibiotics. Based on these results, we intended to identify the potential target enzymes of CyC17/CyC26 in M. abscessus by activity-based protein profiling (ABPP) approach coupled with mass spectrometry differential analysis.