Affiliation:
1. *Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
2. †Department of Cellular Biology, University of Georgia, Athens, GA
Abstract
Abstract
Host cell invasion by Trypanosoma cruzi is a markedly silent process, with limited host transcriptional changes indicative of innate immune recognition, except for a modest type I IFN (IFN-I) response. In this study, we show that T. cruzi–induced IFN-β production was nearly abolished in primary murine cGAS−/− or stimulator of IFN genes (STING)-deficient (STINGGt) macrophages and fibroblasts. T. cruzi infection did not impact the ability of IFN-regulatory factor reporter macrophages to respond to classical cGAS–STING agonists, indicating that the limited IFN-β induction is not due to active parasite suppression. cGAS−/−, STINGGt, and IFN-α/β receptor−/− (IFNAR−/−) macrophages infected with T. cruzi yielded significantly higher numbers of amastigotes compared with wild-type macrophages; however, the impact of the STING pathway during infection in vivo is more complex. Despite an initial increase in parasite growth, STINGGt and IFNAR−/− mice ultimately had lower parasite burden in footpads as compared with wild-type mice, demonstrating a role for IFN-I expression in potentiating parasite growth at the infection site. STING pathway activation had little impact on parasite levels in the skeletal muscle; however, in the heart, cGAS−/− and STINGGt mice, but not IFNAR−/− mice, accumulated higher acute parasite loads, suggesting a protective role of STING sensing of T. cruzi in this organ that was independent of IFN-I. Together, these results demonstrate that host cGAS–STING senses T. cruzi infection, enhancing parasite growth at the site of entry, and contributes to acute-phase parasite restriction in the heart, a major site of tissue damage in chronic T. cruzi infection.
Funder
HHS | NIH | National Institute of Allergy and Infectious Diseases
Publisher
The American Association of Immunologists
Subject
Immunology,Immunology and Allergy
Cited by
2 articles.
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