Biology subjects

Boudehen, Y.-M.

Publications and source records attributed to Boudehen, Y.-M..

5 recordsLinked to original sources

bioRxiv2026

Deep learning extracts MoA-specific signatures from high-throughput images of chemically and genetically perturbed Corynebacteria

Tuberculosis (TB) is the worldwide leading infectious killer due to a single pathogen and increasing antimicrobial resistance (AMR) makes it imperative to discover and develop new drugs with novel modes of action (MoAs) to treat TB infections. Phenotypic screening of chemical libraries has proven effective at identifying new compounds against bacterial pathogens. However, a major limitation of standard screens is their inability to uncover the MoA of hits thereby preventing targeted selection of compounds with novel MoAs. Linking drug perturbations to mutants from images could potentially enable to predict the targets of compounds that act through novel MoAs. Here, we develop a deep learning (DL)-based method to screen drug-treated Corynebacterium glutamicum (Cglu), a surrogate model for Mycobacterium tuberculosis (Mtb). Our DL model is based on a convolutional neural network architecture that takes high throughput images as input and is trained to distinguish between different MoAs. We show that our approach can robustly differentiate between the MoAs of established antibiotics and correctly recognise the MoA of antibiotics that were not previously seen by the DL model. We also show that inhibitors with the same and previously unseen MoA cluster together and apart from all other reference drugs, allowing for new MoA discovery. Importantly, we show that our model links images of chemical (drugs) and genetic (mutants) perturbations targeting similar pathways, thus paving the way towards mutant-based target prediction of compounds that act through novel MoAs, directly from high-content images. Finally, we explore the phenotypes induced by genetic disruption of pathways and demonstrate that features extracted with our DL model recover known biological relationships from high-throughput images alone using the cell cycle of Cglu as a case study, a finding with promising potential for fundamental mechanistic studies.

microbiology↗

bioRxiv2025

PacL-organized membrane-associated effluxosomes coordinate multi-metal resistance in Mycobacterium tuberculosis

Metal ion homeostasis is crucial for bacterial pathogens to withstand metal-induced stress during infection. However, the mechanisms underlying bacterial resistance to metal stress remain incompletely understood, particularly how bacteria coordinate responses to simultaneous exposure to multiple metals. Here, we uncover a previously unrecognized mechanism by which Mycobacterium tuberculosis, the causative agent of tuberculosis, orchestrates a coordinated response to multi-metal stress. We demonstrate that M. tuberculosis assembles dynamic, membrane-associated platforms, organized by PacL proteins, that confer resistance to multiple metals simultaneously. PacL proteins function as scaffolds, clustering multiple P-type ATPase (P-ATPase) pumps, CtpC, CtpG, and CtpV, into functional complexes we term "effluxosomes". Our findings show that PacL proteins are critical for stabilizing CtpG within membrane-associated clusters, conferring cadmium tolerance, while CtpC serves as a backup, promoting cross-resistance to both zinc and cadmium. Using super-resolution microscopy and single-particle tracking, we elucidate the 3D structure and dynamics of effluxosomes in the mycobacterial membrane. We further demonstrate that conserved residues within the transmembrane domain of PacL proteins are crucial for the assembly of dynamic effluxosomes, which are essential for P-ATPase activity. Additionally, we reveal that PacL1 exhibits metallochaperone activity, binding zinc, cadmium, and copper via a conserved C-terminal motif. Proximity labeling further identifies an extensive PacL1 interaction network, encompassing multiple proteins involved in stress adaptation. Our findings introduce effluxosomes as dynamic, membrane-associated efflux machineries that mediate coordinated multi-metal resistance in M. tuberculosis, providing new insights into bacterial metal homeostasis and unveiling potential antimicrobial targets.

microbiology↗

bioRxiv2024

The diversity of clinical Mycobacterium abscessus isolates in morphology, glycopeptidolipids and infection rates in a macrophage model

Mycobacterium abscessus (Mab) colonies adopt smooth (S) or rough (R) morphotypes, which are linked to the presence or absence of glycopeptidolipids (GPL), respectively. Though clinically relevant, the association between GPL levels, morphotype and pathogenesis are poorly understood. To investigate the degree of correlation between Mab morphology, GPL levels, and infectivity, we generated isolates from Mab-positive sputum samples from cystic fibrosis patients. Isolated strains were categorised based on their morphology, GPL profile, and replication rate in macrophages. Our findings revealed that around 50% of isolates displayed mixed morphologies and GPL analysis confirmed a consistent relationship between GPL content and morphotype was only found in smooth isolates. Across morphotype groups, no differences were observed in vitro, yet using a high-content THP-1 cell ex vivo infection model, clinical R strains were observed to replicate at higher levels. Moreover, the proportion of infected macrophages was notably higher among clinical R strains compared to their S counterparts at 72 hours post-infection. Clinical variants also infected at significantly higher rates compared to laboratory strains, highlighting the limited translatability of lab strain infection data to clinical contexts. Our study confirmed the general correlation between morphotype and GPL levels in smooth strains yet unveiled more variability within morphotype groups than previously recognised, particularly during intracellular infection. As the rough morphotype is of highest clinical concern, these findings contribute to the expanding knowledge base surrounding Mab infections, offering insights that can steer diagnostic methodologies, and treatment approaches.

microbiology↗

bioRxiv2021

Mycobacterial resistance to zinc poisoning requires assembly of P-ATPase-containing membrane metal efflux platforms

Transition metals are toxic at high concentrations. The P1B-ATPase metal exporter CtpC/Rv3270 is required for resistance to zinc poisoning in the human pathogen Mycobacterium tuberculosis. Here, we discovered that zinc resistance also depends on the chaperone-like protein PacL1/Rv3269. PacL1 bound Zn2+, but unlike PacL1 and CtpC, the PacL1 metal-binding motif (MBM) was required only at high zinc concentrations. PacL1 co-localized with CtpC in dynamic microdomains within the mycobacterial plasma membrane. Microdomain formation did not require flotillins nor the PacL1 MBM. Instead, loss of the PacL1 Glutamine/Alanine repeats led to loss of CtpC and sensitivity to zinc. PacL1 and CtpC are within the same operon, and homologous PacL1-P1B-ATPase pairs are widely distributed within and across prokaryotes. PacL1 colocalized and functioned redundantly with PacL orthologs in Mycobacterium tuberculosis. Overall, our study suggests that PacL proteins are scaffolds that assemble P-ATPase-containing metal efflux platforms, a novel type of functional membrane microdomain that underlies bacterial resistance to metal poisoning.

microbiology↗

bioRxiv2019

An improved Xer-cise technology for the generation of multiple unmarked mutants in Mycobacteria

Xer-cise is a technique using antibiotic resistance cassettes flanked by dif sites allowing spontaneous and accurate excision from bacterial chromosomes with a high frequency through the action of the cellular recombinase XerCD. Here, we report a significant improvement of Xer-cise in Mycobacteria. Zeocin-resistance cassettes flanked by variants of the natural Mycobacterium tuberculosis dif site were constructed and shown to be effective tools to construct multiple unmarked mutations in M. tuberculosis and in the model species Mycobacterium smegmatis. The dif site variants harbor mutations in the central region and can therefore not recombine with the wild type or other variants, resulting in mutants of increased genetic stability. The herein described method should be generalizable to virtually any transformable bacterial species.\n\nMethod summarydif-ZeoR-dif cassettes are used to replace non-essential genes in mycobacterial genome through recombineering. Spontaneous excision of the cassette is carried out under the action of the recombinase XerCD, resulting in unmarked deletions. Subsequent rounds of mutagenesis using cassettes flanked by a range of dif site variants allow construction of multiple mutants in which the different dif sites cannot recombine which each other, yielding stable genetic constructs.

microbiology↗