IL-1R regulates disease tolerance and cachexia in Toxoplasma gondii infection

SJ Melchor, CM Saunders, I Sanders… - The Journal of …, 2020 - journals.aai.org
SJ Melchor, CM Saunders, I Sanders, JA Hatter, KA Byrnes, S Coutermarsh-Ott, SE Ewald
The Journal of Immunology, 2020journals.aai.org
Toxoplasma gondii is an obligate intracellular parasite that establishes life-long infection in
a wide range of hosts, including humans and rodents. To establish a chronic infection,
pathogens often exploit the trade-off between resistance mechanisms, which promote
inflammation and kill microbes, and tolerance mechanisms, which mitigate inflammatory
stress. Signaling through the type I IL-1R has recently been shown to control disease
tolerance pathways in endotoxemia and Salmonella infection. However, the role of the IL-1 …
Abstract
Toxoplasma gondii is an obligate intracellular parasite that establishes life-long infection in a wide range of hosts, including humans and rodents. To establish a chronic infection, pathogens often exploit the trade-off between resistance mechanisms, which promote inflammation and kill microbes, and tolerance mechanisms, which mitigate inflammatory stress. Signaling through the type I IL-1R has recently been shown to control disease tolerance pathways in endotoxemia and Salmonella infection. However, the role of the IL-1 axis in T. gondii infection is unclear. In this study we show that IL-1R−/− mice can control T. gondii burden throughout infection. Compared with wild-type mice, IL-1R−/− mice have more severe liver and adipose tissue pathology during acute infection, consistent with a role in acute disease tolerance. Surprisingly, IL-1R−/− mice had better long-term survival than wild-type mice during chronic infection. This was due to the ability of IL-1R−/− mice to recover from cachexia, an immune-metabolic disease of muscle wasting that impairs fitness of wild-type mice. Together, our data indicate a role for IL-1R as a regulator of host homeostasis and point to cachexia as a cost of long-term reliance on IL-1–mediated tolerance mechanisms.
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