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Zhao XY, Lempke SL, Urbán Arroyo JC, Brown IG, Yin B, Magaj MM, Holness NK, Smiley J, Redemann S, Ewald SE. iNOS is necessary for GBP-mediated T. gondii clearance in murine macrophages via vacuole nitration and intravacuolar network collapse. Nat Commun 2024; 15:2698. [PMID: 38538595 PMCID: PMC10973475 DOI: 10.1038/s41467-024-46790-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 03/04/2024] [Indexed: 04/02/2024] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite of rodents and humans. Interferon-inducible guanylate binding proteins (GBPs) are mediators of T. gondii clearance, however, this mechanism is incomplete. Here, using automated spatially targeted optical micro proteomics we demonstrate that inducible nitric oxide synthetase (iNOS) is highly enriched at GBP2+ parasitophorous vacuoles (PV) in murine macrophages. iNOS expression in macrophages is necessary to limit T. gondii load in vivo and in vitro. Although iNOS activity is dispensable for GBP2 recruitment and PV membrane ruffling; parasites can replicate, egress and shed GBP2 when iNOS is inhibited. T. gondii clearance by iNOS requires nitric oxide, leading to nitration of the PV and collapse of the intravacuolar network of membranes in a chromosome 3 GBP-dependent manner. We conclude that reactive nitrogen species generated by iNOS cooperate with GBPs to target distinct structures in the PV that are necessary for optimal parasite clearance in macrophages.
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Affiliation(s)
- Xiao-Yu Zhao
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Samantha L Lempke
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jan C Urbán Arroyo
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Isabel G Brown
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Bocheng Yin
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Magdalena M Magaj
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Nadia K Holness
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jamison Smiley
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology, Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA, USA.
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Zhao XY, Lempke SL, Urbán Arroyo JC, Yin B, Holness NK, Smiley J, Ewald SE. Inducible nitric oxide synthase (iNOS) is necessary for GBP-mediated T. gondii restriction in murine macrophages via vacuole nitration and intravacuolar network collapse. bioRxiv 2023:2023.07.24.549965. [PMID: 37546987 PMCID: PMC10402109 DOI: 10.1101/2023.07.24.549965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Toxoplasma gondii is an obligate intracellular, protozoan pathogen of rodents and humans. T. gondii's ability to grow within cells and evade cell-autonomous immunity depends on the integrity of the parasitophorous vacuole (PV). Interferon-inducible guanylate binding proteins (GBPs) are central mediators of T. gondii clearance, however, the precise mechanism linking GBP recruitment to the PV and T. gondii restriction is not clear. This knowledge gap is linked to heterogenous GBP-targeting across a population of vacuoles and the lack of tools to selectively purify the intact PV. To identify mediators of parasite clearance associated with GBP2-positive vacuoles, we employed a novel protein discovery tool automated spatially targeted optical micro proteomics (autoSTOMP). This approach identified inducible nitric oxide synthetase (iNOS) enriched at levels similar to the GBPs in infected bone marrow-derived myeloid cells. iNOS expression on myeloid cells was necessary for mice to control T. gondii growth in vivo and survive acute infection. T. gondii infection of IFNγ-primed macrophage was sufficient to robustly induce iNOS expression. iNOS restricted T. gondii infection through nitric oxide synthesis rather than arginine depletion, leading to robust and selective nitration of the PV. Optimal parasite restriction by iNOS and vacuole nitration depended on the chromosome 3 GBPs. Notably, GBP2 recruitment and ruffling of the PV membrane occurred in iNOS knockouts, however, these vacuoles contained dividing parasites. iNOS activity was necessary for the collapse of the intravacuolar network of nanotubular membranes which connects parasites to each other and the host cytosol. Based on these data we conclude reactive nitrogen species generated by iNOS cooperate with the chromosome 3 GBPs to target distinct biology of the PV that are necessary for optimal parasite clearance in murine myeloid cells.
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Affiliation(s)
- Xiao-Yu Zhao
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Samantha L. Lempke
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jan C. Urbán Arroyo
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Bocheng Yin
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Nadia K. Holness
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jamison Smiley
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Sarah E. Ewald
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- The Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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