Fungal-bacterial co-infection of macrophages reveals global reprogramming and adaptation during infection

In this study, we use mass spectrometry (MS)-based proteomics to define the host response under single and dual infection states of macrophages with C. neoformans and K. pneumoniae to define critical responses of each biological system. This high-resolution comparative analysis illustrates how protein abundance deviates during a transition from an acute to chronic infectious state with exposure to additional microbial stimuli. We reveal global changes upon infection followed by pathogen-specific host response signatures. Additionally, we define regulatory changes within C. neoformans as the fungi adapts to the host environment and stabilizes prior to further disruption in the presence of chronic bacterial infection. We validate our findings with host cytokine detection and phenotypic profiling of the fungi throughout the host and bacterial exposures. Overall, our study provides an in-depth analysis of cross-kingdom protein level changes during macrophage infection. This information provides new insight into fungal modulation of the immune response, including a stabilization and adaptation of the host and fungi during a chronic infection, which is disrupted upon chronic co-infection with a bacterial pathogen.