Transcriptome of Mycobacterium abscessus in response to transition metals
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ABSTRACT: Antimicrobial resistance (AMR) is one of the major challenges that humans are facing this century. Understanding the mechanisms behind the rise of AMR is crucial to tackle this global threat. Among the triggers of phenotypic antimicrobial resistance, the contribution of transition metals has been understudied in Mycobacterium abscessus (Mabs), a fast-growing non-tuberculous mycobacterium known for its extreme AMR levels. Deeper understanding of the effects of transition metal ions will be beneficial for our knowledge in AMR and the discovery of potential therapeutic targets. Here, we investigated the impact of transition metal ions, nickel, cobalt and copper on the physiology and drug susceptibility of Mabs.
Project description:Mycobacterium abscessus (Mabs) is a fast-growing, non-tuberculous mycobacterium responsible for serious lung infections in patients with cystic fibrosis. This bacterium evolves during the pulmonary infection between a smooth (S) and a rough morphotype (R). We have previously isolated the lsr2 gene as being differentially expressed during the transition between Mabs-S and Mabs-R. lsr2 encodes a pleiotropic transcription factor belonging to the superfamily of nucleoid-associated proteins (NAPs), which play an essential role in the hierarchical organization of bacterial chromosomes. The present study aims to unravel the molecular role of Lsr2 in regulating expression of gene involved in the adaptation and the pathobiology of Mabs using both RNA-Seq and ChIP-seq.
Project description:Mycobacterium abscessus (Mabs) is a fast-growing, non-tuberculous mycobacterium responsible for serious lung infections in patients with cystic fibrosis. This bacterium evolves during the pulmonary infection between a smooth (S) and a rough morphotype (R). We have previously isolated the lsr2 gene as being differentially expressed during the transition between Mabs-S and Mabs-R. lsr2 encodes a pleiotropic transcription factor belonging to the superfamily of nucleoid-associated proteins (NAPs), which play an essential role in the hierarchical organization of bacterial chromosomes. The present study aims to unravel the molecular role of Lsr2 in regulating expression of gene involved in the adaptation and the pathobiology of Mabs using both RNA-Seq and ChIP-seq.
Project description:Mycobacterium abscessus (Mabs) biofilms are altered in the presence of exogenous heme. We wanted to determine how protein levels were affected by heme. Mabs cells were grown in a modified media formulated to mimic the nutritional environment of the sputum of cystic fibrosis (CF) patients. Mabs cells grown in synthetic CF media (SCFM) typically form submerged biofilms, exogenous heme treatment however prevents this film formation and supports growth of a pellicle at the air-liquid interface. Heme treatment reduced several iron uptake and homeostasis proteins, suggesting heme is acting as an iron source for these bacteria. In addition, multiple proteins were upregulated in heme treatment, however, the function of these proteins remains to be determined.
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:Mycobacterium abscessus is one of the common clinical non-tuberculous mycobacteria (NTM) which can cause severe skin infections. 5-Aminolevulinic acid photodynamic therapy (ALA_PDT) is an emerming effective antimicrobial medication. To explore whether ALA_PDT can treat M. abscessus infections, we found that ALA_PDT can kill M. abscesses via colony forming unit method. ALA_PDT promoted ferroptosis-like death of M. abscesses, and the antioxidant N-Acetyl-L-cysteine (NAC) and ferroptosis inhibitor Ferrostatin-1(Fer-1) can mitigate the ALA_PDT-mediated sterilization. Furthermore, ALA_PDT significantly up-regulated the transcription of heme oxygenase MAB_4773, increased the intracellular Fe2+ concentration, altering the transcription of M. abscessus iron metabolism genes. ALA_PDT disrupted the integrity of the cell membrane and enhanced the permeability of the cell membrane, as evidenced by the boosted sterilization effect of antibiotics. In summary, ALA_PDT can kill M. abscesses via promoting the ferroptosis-like death and antibiotic sterilization through oxidative stress. This new mechanism of ALA_PDT against M. abscessus might underlie its clinical efficacy.
Project description:RNA sequencing (RNA-seq) of Mycobacterium abscessus in four infection-relevant culture conditions: hypoxic stress, artificial sputum medium, kanamycin-treated medium, and erythromycin-treated medium. Triplicate cultures of M. abscessus were grown in (1) Artificial Sputum media, (2) hypoxic conditions, (3) the presence of kanamycin, and (4) the presence of erythromycin. Triplicate controls were prepared for sample (1) and samples (2-4).
Project description:Generation and analysis of human macrophages from induced pluripotent stem cells were infected by Mycobacterium abscessus to examine susceptibility and transcriptomic response