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Singh AK, Al Qureshah F, Drow T, Hou B, Rawlings DJ. Activated PI3Kδ Specifically Perturbs Mouse Regulatory T Cell Homeostasis and Function Leading to Immune Dysregulation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 213:135-147. [PMID: 38829130 PMCID: PMC11232928 DOI: 10.4049/jimmunol.2400032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024]
Abstract
FOXP3+ regulatory T cells (Treg) are required for maintaining immune tolerance and preventing systemic autoimmunity. PI3Kδ is required for normal Treg development and function. However, the impacts of dysregulated PI3Kδ signaling on Treg function remain incompletely understood. In this study, we used a conditional mouse model of activated PI3Kδ syndrome to investigate the role of altered PI3Kδ signaling specifically within the Treg compartment. Activated mice expressing a PIK3CD gain-of-function mutation (aPIK3CD) specifically within the Treg compartment exhibited weight loss and evidence for chronic inflammation, as demonstrated by increased memory/effector CD4+ and CD8+ T cells with enhanced IFN-γ secretion, spontaneous germinal center responses, and production of broad-spectrum autoantibodies. Intriguingly, aPIK3CD facilitated Treg precursor development within the thymus and an increase in peripheral Treg numbers. Peripheral Treg, however, exhibited an altered phenotype, including increased PD-1 expression and reduced competitive fitness. Consistent with these findings, Treg-specific aPIK3CD mice mounted an elevated humoral response following immunization with a T cell-dependent Ag, which correlated with a decrease in follicular Treg. Taken together, these findings demonstrate that an optimal threshold of PI3Kδ activity is critical for Treg homeostasis and function, suggesting that PI3Kδ signaling in Treg might be therapeutically targeted to either augment or inhibit immune responses.
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Affiliation(s)
- Akhilesh K Singh
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Fahd Al Qureshah
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
- Department of Immunology, University of Washington, Seattle, WA
- Wellness and Preventive Medicine Institute, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Travis Drow
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
| | - Baidong Hou
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - David J Rawlings
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA
- Department of Immunology, University of Washington, Seattle, WA
- Department of Pediatrics, University of Washington, Seattle, WA
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Singh AK, Qureshah FA, Drow T, Hou B, Rawlings DJ. Activated PI3Kδ specifically perturbs mouse Treg homeostasis and function leading to immune dysregulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.569665. [PMID: 38187650 PMCID: PMC10769388 DOI: 10.1101/2023.12.21.569665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Foxp3+ regulatory T cells (Treg) are required for maintaining immune tolerance and preventing systemic autoimmunity. PI3Kδ is required for normal Treg development and function. However, the impacts of dysregulated PI3Kδ signaling on Treg function remain incompletely understood. Here, we used a conditional mouse model of activated PI3Kδ syndrome (APDS) to investigate the role of altered PI3Kδ signaling specifically within the Treg compartment. Aged mice expressing a PIK3CD gain-of-function mutation (aPIK3CD) specifically within the Treg compartment exhibited weight loss and evidence for chronic inflammation as demonstrated by increased memory/effector CD4+ and CD8+ T cells with enhanced IFN-γ secretion, spontaneous germinal center responses and production of broad-spectrum autoantibodies. Intriguingly, aPIK3CD facilitated Treg precursor development within the thymus and an increase in peripheral Treg numbers. Peripheral Treg, however, exhibited an altered phenotype including increased PD1 expression and reduced competitive fitness. Consistent with these findings, Treg specific-aPIK3CD mice mounted an elevated humoral response following immunization with a T-cell dependent antigen, that correlated with a decrease in follicular Treg. Taken together, these findings demonstrate that an optimal threshold of PI3Kδ activity is critical for Treg homeostasis and function, suggesting that PI3Kδ signaling in Treg might be therapeutically targeted to either augment or inhibit immune responses.
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Affiliation(s)
- Akhilesh K. Singh
- Center for Immunity and Immunotherapy, Seattle Children’s Research Institute, Seattle, WA
| | - Fahd Al Qureshah
- Center for Immunity and Immunotherapy, Seattle Children’s Research Institute, Seattle, WA
- Department of Immunology, University of Washington, Seattle, WA
- King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Travis Drow
- Center for Immunity and Immunotherapy, Seattle Children’s Research Institute, Seattle, WA
| | - Baidong Hou
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - David J Rawlings
- Center for Immunity and Immunotherapy, Seattle Children’s Research Institute, Seattle, WA
- Department of Immunology, University of Washington, Seattle, WA
- Department of Pediatrics, University of Washington, Seattle, WA
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Nguyen T, Lau A, Bier J, Cooke KC, Lenthall H, Ruiz-Diaz S, Avery DT, Brigden H, Zahra D, Sewell WA, Droney L, Okada S, Asano T, Abolhassani H, Chavoshzadeh Z, Abraham RS, Rajapakse N, Klee EW, Church JA, Williams A, Wong M, Burkhart C, Uzel G, Croucher DR, James DE, Ma CS, Brink R, Tangye SG, Deenick EK. Human PIK3R1 mutations disrupt lymphocyte differentiation to cause activated PI3Kδ syndrome 2. J Exp Med 2023; 220:e20221020. [PMID: 36943234 PMCID: PMC10037341 DOI: 10.1084/jem.20221020] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 12/22/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
Heterozygous loss-of-function (LOF) mutations in PIK3R1 (encoding phosphatidylinositol 3-kinase [PI3K] regulatory subunits) cause activated PI3Kδ syndrome 2 (APDS2), which has a similar clinical profile to APDS1, caused by heterozygous gain-of-function (GOF) mutations in PIK3CD (encoding the PI3K p110δ catalytic subunit). While several studies have established how PIK3CD GOF leads to immune dysregulation, less is known about how PIK3R1 LOF mutations alter cellular function. By studying a novel CRISPR/Cas9 mouse model and patients' immune cells, we determined how PIK3R1 LOF alters cellular function. We observed some overlap in cellular defects in APDS1 and APDS2, including decreased intrinsic B cell class switching and defective Tfh cell function. However, we also identified unique APDS2 phenotypes including defective expansion and affinity maturation of Pik3r1 LOF B cells following immunization, and decreased survival of Pik3r1 LOF pups. Further, we observed clear differences in the way Pik3r1 LOF and Pik3cd GOF altered signaling. Together these results demonstrate crucial differences between these two genetic etiologies.
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Affiliation(s)
- Tina Nguyen
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - Anthony Lau
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - Julia Bier
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - Kristen C. Cooke
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
| | - Helen Lenthall
- Garvan Institute of Medical Research, Darlinghurst, Australia
| | | | | | - Henry Brigden
- Garvan Institute of Medical Research, Darlinghurst, Australia
| | - David Zahra
- Garvan Institute of Medical Research, Darlinghurst, Australia
| | - William A Sewell
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - Luke Droney
- Department of Clinical Immunology, Royal Brisbane and Women’s Hospital, Brisbane, Australia
| | - Satoshi Okada
- Department of Pediatrics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takaki Asano
- Department of Pediatrics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Hassan Abolhassani
- Department of Biosciences and Nutrition, Division of Clinical Immunology, Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden
- Research Center for Immunodeficiencies, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Chavoshzadeh
- Pediatric Infections Research Center, Mofid Children’s Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Roshini S. Abraham
- Department of Pathology and Laboratory Medicine, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Nipunie Rajapakse
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Infectious Diseases, Mayo Clinic, Rochester, MN, USA
| | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Joseph A. Church
- Division of Clinical Immunology and Allergy, Children’s Hospital of Los Angeles, Los Angeles, CA, USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andrew Williams
- Clinical Immunogenomics Research Consortium Australasia, Sydney, Australia
- Children’s Hospital at Westmead, Westmead, Australia
- Central Clinical School, University of Sydney, Sydney, Australia
| | - Melanie Wong
- Clinical Immunogenomics Research Consortium Australasia, Sydney, Australia
- Children’s Hospital at Westmead, Westmead, Australia
- Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Christoph Burkhart
- Novartis Institutes for Biomedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Gulbu Uzel
- Laboratory of Clinical Immunology and Microbiology, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David R. Croucher
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - David E. James
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
- School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Cindy S. Ma
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
- Clinical Immunogenomics Research Consortium Australasia, Sydney, Australia
| | - Robert Brink
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
| | - Stuart G. Tangye
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
- Clinical Immunogenomics Research Consortium Australasia, Sydney, Australia
| | - Elissa K. Deenick
- Garvan Institute of Medical Research, Darlinghurst, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, University of New South Wales Sydney, Kensington, Australia
- Clinical Immunogenomics Research Consortium Australasia, Sydney, Australia
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