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Archambault, D.

Publications and source records attributed to Archambault, D..

2 recordsLinked to original sources

Predestined neutrophil heterogeneity in homeostasis varies in transcriptional and phenotypic response to Candida

Once perceived to be homogenous effector cells, neutrophils have since been shown to exhibit population heterogeneity. Here, we established an experimental model of clonal neutrophil heterogeneity using conditionally immortalized clonal granulocyte monocyte progenitors (GMPs) and their mature neutrophil progeny. Transcriptional and epigenetic profiling showed conserved genome-wide signatures of transcription and chromatin accessibility that were specific to individual GMP clones and their paired neutrophil progeny, suggesting that clone specificity is established as early as the GMP stage. Clone-specific genes in vital regulatory pathways were pre-programmed and exhibited delayed expression in the mature neutrophil stage. The clone-specific gene expression in the mature neutrophils paired to enhancer activation in their parental GMPs. To determine whether transcriptional heterogeneity predicted the response to fungal pathogens, neutrophil clones were functionally profiled. Clones demonstrated heterogeneous responses to fungal pathogens in vitro and revealed neutrophil subsets with evidence for tailored functional responses to Candida spp. as well as specific transcriptional and epigenetic patterns that may explain these differences. Together, this work establishes that heterogenous GMP and neutrophil compartments exist under homeostatic conditions and that these represent predefined clusters that are uniquely adapted to control invasive fungal pathogens. Short SummaryClonal neutrophil progenitors demonstrate heterogeneity in transcription and chromatin accessibility which may inform response to later fungal challenges.

immunology↗

Characterization of the cluster MabR prophages of Mycobacterium abscessus and Mycobacterium chelonae

Mycobacterium abscessus is an emerging pathogen of concern in cystic fibrosis and immunocompromised patients and is considered one of the most drug-resistant mycobacteria. The majority of clinical M. abscessus isolates carry one or more prophages that are hypothesized to contribute to virulence and bacterial fitness. The prophage McProf was identified in the genome of the Bergey strain of M. chelonae, and is distinct from previously described prophages of M. abscessus. The McProf genome increases intrinsic antibiotic resistance of M. chelonae and drives expression of the intrinsic antibiotic resistance gene, whiB7, when superinfected by a second phage. The prevalence of McProf-like genomes was determined in sequenced mycobacterial genomes. Related prophage genomes were identified in the genomes of 25 clinical isolates of M. abscessus and assigned to the novel cluster, MabR. The MabR genomes share less than 10% gene content with previously described prophages; however, share features typical of prophages, including polymorphic toxin immunity (PT-Imm) systems.

genomics↗