Affiliation:
1. Department of Cell Physiology and Metabolism, Faculty of Medicine University of Geneva Geneva Switzerland
Abstract
AbstractIngestion and killing of bacteria by phagocytic cells are critical processes to protect the human body from bacterial infections. In addition, some immune cells (neutrophils, NK cells) can release microbicidal molecules in the extracellular medium to eliminate non‐ingested microorganism. Molecular mechanisms involved in the resulting intracellular and extracellular killing are still poorly understood. In this study, we used the amoeba Dictyostelium discoideum as a model phagocyte to investigate the mechanisms allowing intracellular and extracellular killing of Pseudomonas aeruginosa. When a D. discoideum cell establishes a close contact with a P. aeruginosa bacterium, it can either ingest it and kill it in phagosomes, or kill it extracellularly, allowing a direct side‐by‐side comparison of these two killing modalities. Efficient intracellular destruction of P. aeruginosa requires the presence of the Kil2 pump in the phagosomal membrane. On the contrary, extracellular lysis is independent on Kil2 but requires the expression of the superoxide‐producing protein NoxA, and the extracellular release of the AplA bacteriolytic protein. These results shed new light on the molecular mechanisms allowing elimination of P. aeruginosa bacteria by phagocytic cells.
Funder
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Subject
Molecular Biology,Microbiology