Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity
ABSTRACTToxoplasma gondii is an intracellular parasite that can activate the NLRP1 inflammasome leading to macrophage pyroptosis in Lewis rats, but the underlying mechanism is not well understood. In this study, we performed a genome-wide CRISPR screen and identified the dense granule proteins GRA35...
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2024-03-01
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| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mbio.03302-23 |
| _version_ | 1797263240064925696 |
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| author | Yifan Wang L. Robert Hollingsworth Lamba Omar Sangaré Tatiana C. Paredes-Santos Shruthi Krishnamurthy Bennett H. Penn Hao Wu Jeroen P. J. Saeij |
| author_facet | Yifan Wang L. Robert Hollingsworth Lamba Omar Sangaré Tatiana C. Paredes-Santos Shruthi Krishnamurthy Bennett H. Penn Hao Wu Jeroen P. J. Saeij |
| author_sort | Yifan Wang |
| collection | DOAJ |
| description | ABSTRACTToxoplasma gondii is an intracellular parasite that can activate the NLRP1 inflammasome leading to macrophage pyroptosis in Lewis rats, but the underlying mechanism is not well understood. In this study, we performed a genome-wide CRISPR screen and identified the dense granule proteins GRA35, GRA42, and GRA43 as the Toxoplasma effectors mediating cell death in Lewis rat macrophages. GRA35 localizes on the parasitophorous vacuole membrane, where it interacts with the host E3 ubiquitin ligase ITCH. Inhibition of proteasome activity or ITCH knockout prevented pyroptosis in Toxoplasma-infected Lewis rat macrophages, consistent with the “NLRP1 functional degradation model.” However, there was no evidence that ITCH directly ubiquitinates or interacts with rat NLRP1. We also found that GRA35-ITCH interaction affected Toxoplasma fitness in IFNγ-activated human fibroblasts, likely due to ITCH’s role in recruiting ubiquitin and the parasite-restriction factor RNF213 to the parasitophorous vacuole membrane. These findings identify a new role of host E3 ubiquitin ligase ITCH in mediating effector-triggered immunity, a critical concept that involves recognizing intracellular pathogens and initiating host innate immune responses.IMPORTANCEEffector-triggered immunity represents an innate immune defense mechanism that plays a crucial role in sensing and controlling intracellular pathogen infection. The NLRP1 inflammasome in the Lewis rats can detect Toxoplasma infection, which triggers proptosis in infected macrophages and eliminates the parasite’s replication niche. The work reported here revealed that host E3 ubiquitin ligase ITCH is able to recognize and interact with Toxoplasma effector protein GRA35 localized on the parasite-host interface, leading to NLRP1 inflammasome activation in Lewis rat macrophages. Furthermore, ITCH-GRA35 interaction contributes to the restriction of Toxoplasma in human fibroblasts stimulated by IFNγ. Thus, this research provides valuable insights into understanding pathogen recognition and restriction mediated by host E3 ubiquitin ligase. |
| first_indexed | 2024-04-25T00:09:51Z |
| format | Article |
| id | doaj.art-1f12e478b874473fb773f6d60dec647f |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-04-25T00:09:51Z |
| publishDate | 2024-03-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-1f12e478b874473fb773f6d60dec647f2024-03-13T14:01:04ZengAmerican Society for MicrobiologymBio2150-75112024-03-0115310.1128/mbio.03302-23Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunityYifan Wang0L. Robert Hollingsworth1Lamba Omar Sangaré2Tatiana C. Paredes-Santos3Shruthi Krishnamurthy4Bennett H. Penn5Hao Wu6Jeroen P. J. Saeij7Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, USADepartment of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USADepartment of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, USADepartment of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, USADepartment of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, USADepartment of Internal Medicine, Division of Infectious Diseases, UC Davis Health, Sacramento, California, USADepartment of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USADepartment of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, USAABSTRACTToxoplasma gondii is an intracellular parasite that can activate the NLRP1 inflammasome leading to macrophage pyroptosis in Lewis rats, but the underlying mechanism is not well understood. In this study, we performed a genome-wide CRISPR screen and identified the dense granule proteins GRA35, GRA42, and GRA43 as the Toxoplasma effectors mediating cell death in Lewis rat macrophages. GRA35 localizes on the parasitophorous vacuole membrane, where it interacts with the host E3 ubiquitin ligase ITCH. Inhibition of proteasome activity or ITCH knockout prevented pyroptosis in Toxoplasma-infected Lewis rat macrophages, consistent with the “NLRP1 functional degradation model.” However, there was no evidence that ITCH directly ubiquitinates or interacts with rat NLRP1. We also found that GRA35-ITCH interaction affected Toxoplasma fitness in IFNγ-activated human fibroblasts, likely due to ITCH’s role in recruiting ubiquitin and the parasite-restriction factor RNF213 to the parasitophorous vacuole membrane. These findings identify a new role of host E3 ubiquitin ligase ITCH in mediating effector-triggered immunity, a critical concept that involves recognizing intracellular pathogens and initiating host innate immune responses.IMPORTANCEEffector-triggered immunity represents an innate immune defense mechanism that plays a crucial role in sensing and controlling intracellular pathogen infection. The NLRP1 inflammasome in the Lewis rats can detect Toxoplasma infection, which triggers proptosis in infected macrophages and eliminates the parasite’s replication niche. The work reported here revealed that host E3 ubiquitin ligase ITCH is able to recognize and interact with Toxoplasma effector protein GRA35 localized on the parasite-host interface, leading to NLRP1 inflammasome activation in Lewis rat macrophages. Furthermore, ITCH-GRA35 interaction contributes to the restriction of Toxoplasma in human fibroblasts stimulated by IFNγ. Thus, this research provides valuable insights into understanding pathogen recognition and restriction mediated by host E3 ubiquitin ligase.https://journals.asm.org/doi/10.1128/mbio.03302-23E3 ubiquitin ligaseeffector-triggered immunityNLRP1 inflammasomeIFNγToxoplasma gondii |
| spellingShingle | Yifan Wang L. Robert Hollingsworth Lamba Omar Sangaré Tatiana C. Paredes-Santos Shruthi Krishnamurthy Bennett H. Penn Hao Wu Jeroen P. J. Saeij Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity mBio E3 ubiquitin ligase effector-triggered immunity NLRP1 inflammasome IFNγ Toxoplasma gondii |
| title | Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity |
| title_full | Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity |
| title_fullStr | Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity |
| title_full_unstemmed | Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity |
| title_short | Host E3 ubiquitin ligase ITCH mediates Toxoplasma gondii effector GRA35-triggered NLRP1 inflammasome activation and cell-autonomous immunity |
| title_sort | host e3 ubiquitin ligase itch mediates toxoplasma gondii effector gra35 triggered nlrp1 inflammasome activation and cell autonomous immunity |
| topic | E3 ubiquitin ligase effector-triggered immunity NLRP1 inflammasome IFNγ Toxoplasma gondii |
| url | https://journals.asm.org/doi/10.1128/mbio.03302-23 |
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