Spatially-divergent metabolic impact of experimental toxoplasmosis: immunological and microbial correlates

Abstract

Maladaptive host metabolic responses to infection are emerging as major determinants of infectious disease pathogenesis. However, the factors regulating these metabolic changes within tissues remain poorly understood. In this study, we used toxoplasmosis, as a prototypical example of a disease regulated by strong type I immune responses, to assess the relative roles of local parasite burden, local tissue inflammation and the microbiome in shaping local tissue metabolism during acute and chronic infection. Toxoplasmosis is a zoonotic disease caused by the parasite Toxoplasma gondii. This protozoan infects the small intestine and then disseminates to nearly every organ in the acute stage of infection, before establishing chronic infection in the skeletal muscle, cardiac muscle and brain. We compared metabolism in eleven sampling sites in C57BL/6 mice during the acute and chronic stage of T. gondii infection. Strikingly, significant metabolic changes were observed in the large intestine and colon during chronic infection, organs not associated with T. gondii persistence. Overall, major spatial mismatches were observed between metabolic perturbation and local parasite burden for both disease stages. In contrast, a stronger association with indicators of type I immune responses was observed, indicating a tighter relationship between metabolic perturbation and local immunity, than with local parasite burden. In addition, we observed significant changes in microbiota composition with infection, and candidate microbial origins for multiple metabolites impacted by infection. These findings highlight the metabolic consequences of toxoplasmosis across different organs, and their regulators. ImportanceInflammation is a major driver of tissue perturbation. However, the signals driving these changes on a tissue-intrinsic and molecular level are poorly understood. This study evaluated tissue-specific metabolic perturbations across eleven sampling sites following systemic murine infection with the parasite Toxoplasma gondii. Results revealed relationships between differential metabolite enrichment and variables including inflammatory signals, pathogen burden and commensal microbial communities. These data will inform hypotheses about the signals driving specific metabolic adaptation in acute and chronic protozoan infection, with broader implications for infection and inflammation in general.