Muselius, B. | Search bioRxiv

bioRxiv2023

Resolving the temporal splenic proteome during fungal infection for discovery of putative dual perspective biomarker signatures

Fungal pathogens are emerging threats to global health with the rise of incidence associated with climate change and increased geographical distribution; factors also influencing host susceptibility to infection. Accurate detection and diagnosis of fungal infections is paramount to offer rapid and effective therapeutic options. For improved diagnostics, the discovery and development of protein biomarkers presents a promising avenue; however, this approach requires a priori knowledge of infection hallmarks. To uncover putative novel biomarkers of disease, profiling of the host immune response and pathogen virulence factor production is indispensable. In this study, we use mass spectrometry-based proteomics to resolve the temporal proteome of Cryptococcus neoformans infection of the spleen following a murine model of infection. Dual perspective proteome profiling defines global remodeling of the host over a time course of infection, confirming activation of immune associated proteins in response to fungal invasion. Conversely, pathogen proteomes detect well-characterized C. neoformans virulence determinants, along with novel mapped patterns of pathogenesis during the progression of disease. Together, our innovative systematic approach confirms immune protection against fungal pathogens and explores the discovery of putative biomarker signatures from complementary biological systems to monitor the presence and progression of cryptococcal disease.

microbiology↗

bioRxiv2021

Dual perspective proteomics infectome profiling discovers Salmonella type III secretion system effector functions in macrophages

Intracellular bacterial pathogens have evolved sophisticated infection strategies, including the release and secretion of virulence factors to interfere with host cell functions and to perturb immune responses. For Salmonella enterica serovar Typhimurium (S. Typhimurium), the type III secretion systems encoded on Salmonella pathogenicity islands (SPI) 1 and 2 mediates invasion of the bacterium into innate immune cells and regulates bacterial replication and survival within the hostile environment of the host, respectively. Here, we explore the temporal and strain-specific dual perspective response of both the host and pathogen during cellular infection via quantitative proteomics. We report time- and pathogenicity island-specific expression and secretion of infection-associated proteins (i.e., SL1344_1263, SL1344_3112, SL1344_1563, and YnhG) and regulated immune response proteins in macrophage, including Cd86, Cd40, Casp4, C3, IL-1, and Cd69). Through intracellular macrophage and in vivo murine models of infection, we reveal a role in virulence for three of the bacterial proteins (SL1344_1263, SL1344_1563, and YnhG), defining their importance as novel T3SS effectors. We characterize the temporal intra- and extracellular production of the effectors and identify their interaction networks in host cells, representing inhibitory and stimulatory pathways mounted by invading bacterial pathogens. Author SummaryThe relationship between a host and pathogen is intricate, and regulation of the host immune response correlates with the progressive timing of infection and tailored responses to the pathogen. Relying on detection and quantification of protein-level changes using mass spectrometry-based proteomics, we explore the production of known and novel effectors by Salmonella during intracellular survival within macrophage. Our results portray a role for these effectors in bacterial virulence using an in vivo murine model of infection, and we define a dynamic network of interaction between the effectors and host proteins. These interactions reveal opportunity for drug design to disrupt modulation of the host by the invading bacterium as a new strategy for combatting infection. Our approach is dynamic and universal, with the power to alter therapeutic discovery against infectious diseases.

microbiology↗