Plante, O. | bioRxiv Science

bioRxiv2024

Spatial transcriptomics identifies novel P. aeruginosa virulence factors

To holistically unravel the complexity of pathogen-host interactions within infected tissues we leverage a dual spatial transcriptomic approach that, for the first time, simultaneously captures the expression of Pseudomonas aeruginosa genes alongside the entire host transcriptome in a model of ocular infection. This innovative method reveals differential pathogen and host-specific gene expression patterns across specific anatomical regions generating a unified transcriptional map of infection. By integrating these data, we developed a predictive ridge regression model trained on images from infected tissues. The model achieved an R{superscript 2} score of 0.923 in predicting bacterial burden distributions by using host features thereby predicting novel biomarkers associated with disease severity. Our analysis revealed a complex interplay between P. aeruginosa nutritional requirements and protective host responses and identified novel interactions between bacterial metabolite transport proteins and host autophagy. Among an array of iron acquisition gene transcripts that showed significant enrichment at the host-pathogen interface, we discovered a novel virulence mediator PA2590. This study highlights the power of spatial transcriptomics, particularly in combining bacterial and host transcriptomes, to uncover novel host-pathogen interactions, advance our understanding of bacterial virulence mechanisms, and point to druggable molecules.

microbiology↗

bioRxiv2022

Development of an antibody fused with an antimicrobial peptide targeting Pseudomonas aeruginosa: a new approach to prevent and treat bacterial infections

The increase of emerging drug resistant Gram-negative bacterial infections is of global concern. In addition, there is growing recognition that compromising the microbiota, through the use of broad spectrum antibiotics, may affect patient health in the long term. Therefore, there is the need to develop new -cidal strategies to combat Gram-negative infections that would consider these specific issues. In this study, we report and characterize one such approach, the antibody-drug conjugates (ADCs) that combine (i) targeting a specific pathogenic organism through a monoclonal antibody with (ii) the high killing activity of antimicrobial peptides. We focused on a major pathogenic Gram-negative bacterium associated with antibacterial resistance: Pseudomonas aeruginosa and designed an ADC by fusing an antimicrobial peptide at the C-terminal end of the VH and/or VL-chain of a monoclonal antibody, VSX, that targets the core of P. aeruginosa lipopolysaccharide (LPS). This ADC demonstrated appropriately minimal levels of toxicity to mammalian cells and rapidly kills P. aeruginosa strains through several mechanisms while protecting mice from P. aeruginosa lung infection when administered therapeutically. Furthermore, we found that the ADC was synergistic with several classes of antibiotics. This approach described in this study may result in a widely useful strategy to target specific pathogenic microorganisms without augmenting further antibiotic resistance. Author SummaryThe increasing of emerging drug resistant bacterial infections is a worldwide issue and infections caused by antibiotic resistant Gram-negative pathogens are particularly concerning. In addition, there is now growing recognition that disruption of the microbiota, through the use of broad spectrum antibiotics, may affect patient health in the long term. Therefore, there is the need to develop new -cidal strategies to combat Gram-negative infections while preserving the microbiota and also avoid enhancement of antibiotic resistance. We report and characterize here one such approach by using a specific monoclonal antibody associated with the potent killing activity of antimicrobial peptides in the form of an antibody-drug conjugate (ADC). The selected pathogenic bacterium was Pseudomonas aeruginosa, that presents numerous markers for both innate and acquired antibiotic resistance. The ADC lacked significant cytotoxicity against mammalian cells and was shown to be effective both in vitro and in vivo against P. aeruginosa.

microbiology↗