Temporal and ligand effects on phagosome maturation

Systems biology analysis of temporally-resolved phagosome proteomes following uptake via key phagocytic receptors Macrophages operate at the forefront of innate immunity, and their discrimination of pathogenic versus “self” particles is critical for a number of responses including efficient pathogen killing, antigen presentation and cytokine induction. In order to efficiently phagocytose and destroy the particles, macrophages express an array of receptors to sense and internalise prey particles. In this manuscript, particles conjugated to seven ligands representing pathogen-associated molecular patterns, immune opsonins or apoptotic cell markers were inoculated to murine bone marrow-derived macrophages (BMDMs) and proteomes of isolated phagosomes were accurately quantified among conditions and across a timecourse. While we identified a clear functional differentiation over the three timepoints, only subtle differences were detected between certain ligand-phagosomes, suggesting that triggering of receptors through a single ligand has only mild effects on phagosome proteome and function. This data shows for the first time a systematic time-course analysis of BMDM phagosomes and how phagosome fate is regulated by the receptors triggered for phagocytosis.