1
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Lanahan SM, Yang L, Jones KM, Qi Z, Cabrera EC, Cominsky LY, Ramaswamy A, Barmada A, Gabernet G, Uthaya Kumar DB, Xu L, Shan P, Wymann MP, Kleinstein SH, Rao VK, Mustillo P, Romberg N, Abraham RS, Lucas CL. PI3Kγ in B cells promotes antibody responses and generation of antibody-secreting cells. Nat Immunol 2024; 25:1422-1431. [PMID: 38961274 DOI: 10.1038/s41590-024-01890-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 06/07/2024] [Indexed: 07/05/2024]
Abstract
The differentiation of naive and memory B cells into antibody-secreting cells (ASCs) is a key feature of adaptive immunity. The requirement for phosphoinositide 3-kinase-delta (PI3Kδ) to support B cell biology has been investigated intensively; however, specific functions of the related phosphoinositide 3-kinase-gamma (PI3Kγ) complex in B lineage cells have not. In the present study, we report that PI3Kγ promotes robust antibody responses induced by T cell-dependent antigens. The inborn error of immunity caused by human deficiency in PI3Kγ results in broad humoral defects, prompting our investigation of roles for this kinase in antibody responses. Using mouse immunization models, we found that PI3Kγ functions cell intrinsically within activated B cells in a kinase activity-dependent manner to transduce signals required for the transcriptional program supporting differentiation of ASCs. Furthermore, ASC fate choice coincides with upregulation of PIK3CG expression and is impaired in the context of PI3Kγ disruption in naive B cells on in vitro CD40-/cytokine-driven activation, in memory B cells on toll-like receptor activation, or in human tonsillar organoids. Taken together, our study uncovers a fundamental role for PI3Kγ in supporting humoral immunity by integrating signals instructing commitment to the ASC fate.
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Affiliation(s)
- Stephen M Lanahan
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Lucas Yang
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Kate M Jones
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Zhihong Qi
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Emylette Cruz Cabrera
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Lauren Y Cominsky
- Immunology Graduate Group, Perelman School of Medicine, Philadelphia, PA, USA
| | - Anjali Ramaswamy
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Anis Barmada
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Gisela Gabernet
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Lan Xu
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | - Peiying Shan
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Steven H Kleinstein
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - V Koneti Rao
- Primary Immunodeficiency Clinic, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, MD, USA
| | - Peter Mustillo
- Division of Allergy and Immunology, Department of Pediatrics, Nationwide Children's Hospital, Columbus, OH, USA
| | - Neil Romberg
- Division of Immunology and Allergy, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA, USA
| | - Roshini S Abraham
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Carrie L Lucas
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
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2
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Zhang F, Cheng T, Zhang SX. Mechanistic target of rapamycin (mTOR): a potential new therapeutic target for rheumatoid arthritis. Arthritis Res Ther 2023; 25:187. [PMID: 37784141 PMCID: PMC10544394 DOI: 10.1186/s13075-023-03181-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 09/25/2023] [Indexed: 10/04/2023] Open
Abstract
Rheumatoid arthritis (RA) is an autoimmune disease characterized by systemic synovitis and bone destruction. Proinflammatory cytokines activate pathways of immune-mediated inflammation, which aggravates RA. The mechanistic target of rapamycin (mTOR) signaling pathway associated with RA connects immune and metabolic signals, which regulates immune cell proliferation and differentiation, macrophage polarization and migration, antigen presentation, and synovial cell activation. Therefore, therapy strategies targeting mTOR have become an important direction of current RA treatment research. In the current review, we summarize the biological functions of mTOR, its regulatory effects on inflammation, and the curative effects of mTOR inhibitors in RA, thus providing references for the development of RA therapeutic targets and new drugs.
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Affiliation(s)
- Fen Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
| | - Ting Cheng
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China
| | - Sheng-Xiao Zhang
- Department of Rheumatology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Xinghualing District, Taiyuan, 030001, Shanxi Province, China.
- Shanxi Provincial Key Laboratory of Rheumatism Immune Microecology, Taiyuan, Shanxi Province, China.
- Key Laboratory of Cellular Physiology at Shanxi Medical University, Ministry of Education, Taiyuan, Shanxi Province, China.
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3
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Lam JH, Baumgarth N. Toll-like receptor mediated inflammation directs B cells towards protective antiviral extrafollicular responses. Nat Commun 2023; 14:3979. [PMID: 37407556 DOI: 10.1038/s41467-023-39734-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/27/2023] [Indexed: 07/07/2023] Open
Abstract
Extrafollicular plasmablast responses (EFRs) are considered to generate antibodies of low affinity that offer little protection from infections. Paradoxically, high avidity antigen-B cell receptor engagement is thought to be the main driver of B cell differentiation, whether in EFRs or slower-developing germinal centers (GCs). Here we show that influenza infection rapidly induces EFRs, generating protective antibodies via Toll-like receptor (TLR)-mediated mechanisms that are both B cell intrinsic and extrinsic. B cell-intrinsic TLR signals support antigen-stimulated B cell survival, clonal expansion, and the differentiation of B cells via induction of IRF4, the master regulator of B cell differentiation, through activation of NF-kB c-Rel. Provision of sustained TLR4 stimulation after immunization shifts the fate of virus-specific B cells towards EFRs instead of GCs, prompting rapid antibody production and improving their protective capacity over antigen/alum administration alone. Thus, inflammatory signals act as B cell fate-determinants for the rapid generation of protective antiviral extrafollicular responses.
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Affiliation(s)
- Jonathan H Lam
- Graduate Group in Immunology, University of California Davis, Davis, USA
- Center for Immunology and Infectious Diseases, University of California Davis, Davis, USA
- Dept. Pathology, Microbiology and Immunology, University of California Davis, Davis, USA
| | - Nicole Baumgarth
- Graduate Group in Immunology, University of California Davis, Davis, USA.
- Center for Immunology and Infectious Diseases, University of California Davis, Davis, USA.
- Dept. Pathology, Microbiology and Immunology, University of California Davis, Davis, USA.
- W. Harry Feinstone Dept Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, E4135, Baltimore, MD, 21205, USA.
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4
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Sadeghi Shaker M, Rokni M, Mahmoudi M, Farhadi E. Ras family signaling pathway in immunopathogenesis of inflammatory rheumatic diseases. Front Immunol 2023; 14:1151246. [PMID: 37256120 PMCID: PMC10225558 DOI: 10.3389/fimmu.2023.1151246] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/26/2023] [Indexed: 06/01/2023] Open
Abstract
The Ras (rat sarcoma virus) is a GTP-binding protein that is considered one of the important members of the Ras-GTPase superfamily. The Ras involves several pathways in the cell that include proliferation, migration, survival, differentiation, and fibrosis. Abnormalities in the expression level and activation of the Ras family signaling pathway and its downstream kinases such as Raf/MEK/ERK1-2 contribute to the pathogenic mechanisms of rheumatic diseases including immune system dysregulation, inflammation, and fibrosis in systemic sclerosis (SSc); destruction and inflammation of synovial tissue in rheumatoid arthritis (RA); and autoantibody production and immune complexes formation in systemic lupus erythematosus (SLE); and enhance osteoblast differentiation and ossification during skeletal formation in ankylosing spondylitis (AS). In this review, the basic biology, signaling of Ras, and abnormalities in this pathway in rheumatic diseases including SSc, RA, AS, and SLE will be discussed.
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Affiliation(s)
- Mina Sadeghi Shaker
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Rokni
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Department of Immunology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mahdi Mahmoudi
- Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Inflammation Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Farhadi
- Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Inflammation Research Center, Tehran University of Medical Sciences, Tehran, Iran
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5
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Sun Y, Wen J, Xu T, Meng L. Reduction of peritoneal cavity B1a cells in adult Slc7a5 knockdown mice via dysregulating the mTOR pathway. Int Immunopharmacol 2023; 117:109939. [PMID: 37012862 DOI: 10.1016/j.intimp.2023.109939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/12/2023]
Abstract
Slc7a5 is an important amino acid transporter that is highly expressed in metabolically active and rapidly proliferating cells. To explore the effect of Slc7a5 on adult B cell development, we conditionally deleted Slc7a5 in murine B cells and observed a significant reduction of B1a cells. In contrast to PI3K-Akt pathway activation, activity of the mTOR pathway was decreased. This may result from intracellular amino acid starvation in Slc7a5 knockdown (Slc7a5 KD) bone marrow B cells, thereby dampening B1a development. RNA-seq analysis demonstrated increased translation and reduced proliferation in Slc7a5 KD bone marrow B cells. Overall, the results of our study highlight the importance of Slc7a5 in peritoneal B1a cell development.
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Affiliation(s)
- Yumeng Sun
- CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China University of Chinese Academy of Sciences, Beijing, China
| | - Junjie Wen
- CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China University of Chinese Academy of Sciences, Beijing, China
| | - Tao Xu
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Huashan Hospital, State Key Laboratory of Genetic Engineering, School of Life Science, Fudan University, Shanghai, China
| | - Lu Meng
- CAS Key Laboratory of Molecular Virology and Immunology, Chinese Academy of Sciences, Shanghai, China University of Chinese Academy of Sciences, Beijing, China.
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6
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Glutathione-dependent redox balance characterizes the distinct metabolic properties of follicular and marginal zone B cells. Nat Commun 2022; 13:1789. [PMID: 35379825 PMCID: PMC8980022 DOI: 10.1038/s41467-022-29426-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
The metabolic principles underlying the differences between follicular and marginal zone B cells (FoB and MZB, respectively) are not well understood. Here we show, by studying mice with B cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), that glutathione synthesis affects homeostasis and differentiation of MZB to a larger extent than FoB, while glutathione-dependent redox control contributes to the metabolic dependencies of FoB. Specifically, Gclc ablation in FoB induces metabolic features of wild-type MZB such as increased ATP levels, glucose metabolism, mTOR activation, and protein synthesis. Furthermore, Gclc-deficient FoB have a block in the mitochondrial electron transport chain (ETC) due to diminished complex I and II activity and thereby accumulate the tricarboxylic acid cycle metabolite succinate. Finally, Gclc deficiency hampers FoB activation and antibody responses in vitro and in vivo, and induces susceptibility to viral infections. Our results thus suggest that Gclc is required to ensure the development of MZB, the mitochondrial ETC integrity in FoB, and the efficacy of antiviral humoral immunity. Follicular and marginal zone B (FoB and MZB, respectively) cells have divergent metabolic characteristics. Here the authors show that deficiency of glutamate cysteine ligase (Gclc), the enzyme for glutathione synthesis, differentially impacts FoB and MZB homeostasis, while specifically impeding FoB activation and downstream antiviral immunity.
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7
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Modulation of the mTOR pathway plays a central role in dendritic cell functions after Echinococcus granulosus antigen recognition. Sci Rep 2021; 11:17238. [PMID: 34446757 PMCID: PMC8390662 DOI: 10.1038/s41598-021-96435-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 07/09/2021] [Indexed: 12/12/2022] Open
Abstract
Immune evasion is a hallmark of persistent echinococcal infection, comprising modulation of innate immune cells and antigen-specific T cell responses. However, recognition of Echinococcus granulosus by dendritic cells (DCs) is a key determinant of the host's response to this parasite. Given that mTOR signaling pathway has been described as a regulator linking metabolism and immune function in DCs, we reported for the first time in these cells, global translation levels, antigen uptake, phenotype, cytokine transcriptional levels, and splenocyte priming activity upon recognition of the hydatid fluid (HF) and the highly glycosylated laminar layer (LL). We found that LL induced a slight up-regulation of CD86 and MHC II in DCs and also stimulated the production of IL-6 and TNF-α. By contrast, HF did not increase the expression of any co-stimulatory molecules, but also down-modulated CD40 and stimulated the expression of the anti-inflammatory cytokine IL-10. Both parasitic antigens promoted protein synthesis through mTOR activation. The use of rapamycin decreased the expression of the cytokines tested, empowered the down-modulation of CD40 and also reduced splenocyte proliferation. Finally, we showed that E. granulosus antigens increase the amounts of LC3-positive structures in DCs which play critical roles in the presentation of these antigens to T cells.
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8
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Gaudette BT, Allman D. Biochemical coordination of plasma cell genesis. Immunol Rev 2021; 303:52-61. [PMID: 34313339 DOI: 10.1111/imr.12992] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/29/2021] [Indexed: 12/24/2022]
Abstract
Antibody-secreting plasma cells are a central component of short- and long-term adaptive immunity. Yet, many fundamental questions about how activated B cells decide to yield functional plasma cells have yet to be answered. Likewise, the biochemical processes underpinning the ability of plasma cells to generate and secrete large numbers of antibodies, the capacity of some plasma cell to sustain antibody secretion, presumably without interruption, for decades, and the capacity of long-lived plasma cells to avoid apoptosis despite the high-energy demands associated with sustained robust antibody synthesis and secretion each remain mysterious processes. Our objective here is to review what is currently known about these processes with an emphasis on the earliest phases of plasma cell genesis. Along the way, we will work toward developing a model that ties the biochemistry of plasma cell function and survival. The chief idea imbedded in this model is that progress toward understanding plasma cell survival mechanisms may require increased focus on the unique cell autonomous processes inherent in plasma cell differentiation and function.
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Affiliation(s)
- Brian T Gaudette
- The Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David Allman
- The Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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9
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Aydin E, Faehling S, Saleh M, Llaó Cid L, Seiffert M, Roessner PM. Phosphoinositide 3-Kinase Signaling in the Tumor Microenvironment: What Do We Need to Consider When Treating Chronic Lymphocytic Leukemia With PI3K Inhibitors? Front Immunol 2021; 11:595818. [PMID: 33552053 PMCID: PMC7857022 DOI: 10.3389/fimmu.2020.595818] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) and their downstream proteins constitute a signaling pathway that is involved in both normal cell growth and malignant transformation of cells. Under physiological conditions, PI3K signaling regulates various cellular functions such as apoptosis, survival, proliferation, and growth, depending on the extracellular signals. A deterioration of these extracellular signals caused by mutational damage in oncogenes or growth factor receptors may result in hyperactivation of this signaling cascade, which is recognized as a hallmark of cancer. Although higher activation of PI3K pathway is common in many types of cancer, it has been therapeutically targeted for the first time in chronic lymphocytic leukemia (CLL), demonstrating its significance in B-cell receptor (BCR) signaling and malignant B-cell expansion. The biological activity of the PI3K pathway is not only limited to cancer cells but is also crucial for many components of the tumor microenvironment, as PI3K signaling regulates cytokine responses, and ensures the development and function of immune cells. Therefore, the success or failure of the PI3K inhibition is strongly related to microenvironmental stimuli. In this review, we outline the impacts of PI3K inhibition on the tumor microenvironment with a specific focus on CLL. Acknowledging the effects of PI3K inhibitor-based therapies on the tumor microenvironment in CLL can serve as a rationale for improved drug development, explain treatment-associated adverse events, and suggest novel combinatory treatment strategies in CLL.
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Affiliation(s)
- Ebru Aydin
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Institute of Clinical Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Sebastian Faehling
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Medical Faculty, University of Heidelberg, Heidelberg, Germany
| | - Mariam Saleh
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Molecular Medicine, Ulm University, Ulm, Germany
| | - Laura Llaó Cid
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Faculty of Bioscience, University of Heidelberg, Heidelberg, Germany
| | - Martina Seiffert
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Philipp M Roessner
- Molecular Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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10
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Preite S, Gomez-Rodriguez J, Cannons JL, Schwartzberg PL. T and B-cell signaling in activated PI3K delta syndrome: From immunodeficiency to autoimmunity. Immunol Rev 2020; 291:154-173. [PMID: 31402502 DOI: 10.1111/imr.12790] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 05/30/2019] [Indexed: 12/15/2022]
Abstract
Phosphatidylinositol 3 kinases (PI3K) are a family of lipid kinases that are activated by a variety of cell-surface receptors, and regulate a wide range of downstream readouts affecting cellular metabolism, growth, survival, differentiation, adhesion, and migration. The importance of these lipid kinases in lymphocyte signaling has recently been highlighted by genetic analyses, including the recognition that both activating and inactivating mutations of the catalytic subunit of PI3Kδ, p110δ, lead to human primary immunodeficiencies. In this article, we discuss how studies on the human genetic disorder "Activated PI3K-delta syndrome" and mouse models of this disease (Pik3cdE1020K/+ mice) have provided fundamental insight into pathways regulated by PI3Kδ in T and B cells and their contribution to lymphocyte function and disease, including responses to commensal bacteria and the development of autoimmunity and tumors. We highlight critical roles of PI3Kδ in T follicular helper cells and the orchestration of the germinal center reaction, as well as in CD8+ T-cell function. We further present data demonstrating the ability of the AKT-resistant FOXO1AAA mutant to rescue IgG1 class switching defects in Pik3cdE1020K/+ B cells, as well as data supporting a role for PI3Kδ in promoting multiple T-helper effector cell lineages.
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Affiliation(s)
- Silvia Preite
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Julio Gomez-Rodriguez
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Jennifer L Cannons
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Pamela L Schwartzberg
- Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.,National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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11
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Li M, Lazorchak AS, Ouyang X, Zhang H, Liu H, Arojo OA, Yan L, Jin J, Han Y, Qu G, Fu Y, Xu X, Liu X, Zhang W, Yang Z, Ruan C, Wang Q, Liu D, Huang C, Lu L, Jiang S, Li F, Su B. Sin1/mTORC2 regulate B cell growth and metabolism by activating mTORC1 and Myc. Cell Mol Immunol 2019; 16:757-769. [PMID: 30705387 DOI: 10.1038/s41423-018-0185-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022] Open
Abstract
Proper control of B cell growth and metabolism is crucial for B-cell-mediated immunity, but the underlying molecular mechanisms remain incompletely understood. In this study, Sin1, a key component of mTOR complex 2 (mTORC2), specifically regulates B cell growth and metabolism. Genetic ablation of Sin1 in B cells reduces the cell size at either the transitional stage or upon antigen stimulation and severely impairs metabolism. Sin1 deficiency also severely impairs B-cell proliferation, antibody responses, and anti-viral immunity. At the molecular level, Sin1 controls the expression and stability of the c-Myc protein and maintains the activity of mTORC1 through the Akt-dependent inactivation of GSK3 and TSC1/2, respectively. Therefore, our study reveals a novel and specific role for Sin1 in coordinating the activation of mTORC2 and mTORC1 to control B cell growth and metabolism.
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Affiliation(s)
- Man Li
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Adam S Lazorchak
- Department of Immunobiology and the Vascular Biology and Therapeutics Program, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06520, USA.,EMD Serono Research & Development Institute, Inc., 45 Middlesex Tpke, Billerica, MA, 01821-3936, USA
| | - Xinxing Ouyang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Huihui Zhang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.,Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and Faculty of Basic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hongzhi Liu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Omotooke A Arojo
- Department of Immunobiology and the Vascular Biology and Therapeutics Program, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06520, USA
| | - Lichong Yan
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jingsi Jin
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yuheng Han
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Guojun Qu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yuhong Fu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology of MOE/MOH, Fudan University, Shanghai, China
| | - Xiaocao Xu
- Department of Immunobiology and the Vascular Biology and Therapeutics Program, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06520, USA
| | - Xiaobo Liu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.,Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and Faculty of Basic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wenqian Zhang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.,Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and Faculty of Basic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zhengfeng Yang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Chuan Ruan
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qijun Wang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Dou Liu
- Department of Immunobiology and the Vascular Biology and Therapeutics Program, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06520, USA
| | - Chuanxin Huang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Lu Lu
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology of MOE/MOH, Fudan University, Shanghai, China
| | - Shibo Jiang
- Shanghai Public Health Clinical Center and School of Basic Medical Sciences, Key Laboratory of Medical Molecular Virology of MOE/MOH, Fudan University, Shanghai, China
| | - Fubin Li
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. .,Hongqiao International Institute of Medicine, Shanghai Tongren Hospital and Faculty of Basic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Bing Su
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. .,Department of Immunobiology and the Vascular Biology and Therapeutics Program, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06520, USA.
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12
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Tsui C, Martinez-Martin N, Gaya M, Maldonado P, Llorian M, Legrave NM, Rossi M, MacRae JI, Cameron AJ, Parker PJ, Leitges M, Bruckbauer A, Batista FD. Protein Kinase C-β Dictates B Cell Fate by Regulating Mitochondrial Remodeling, Metabolic Reprogramming, and Heme Biosynthesis. Immunity 2018; 48:1144-1159.e5. [PMID: 29884460 PMCID: PMC6015119 DOI: 10.1016/j.immuni.2018.04.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/13/2018] [Accepted: 04/27/2018] [Indexed: 12/12/2022]
Abstract
PKCβ-null (Prkcb-/-) mice are severely immunodeficient. Here we show that mice whose B cells lack PKCβ failed to form germinal centers and plasma cells, which undermined affinity maturation and antibody production in response to immunization. Moreover, these mice failed to develop plasma cells in response to viral infection. At the cellular level, we have shown that Prkcb-/- B cells exhibited defective antigen polarization and mTORC1 signaling. While altered antigen polarization impaired antigen presentation and likely restricted the potential of GC development, defective mTORC1 signaling impaired metabolic reprogramming, mitochondrial remodeling, and heme biosynthesis in these cells, which altogether overwhelmingly opposed plasma cell differentiation. Taken together, our study reveals mechanistic insights into the function of PKCβ as a key regulator of B cell polarity and metabolic reprogramming that instructs B cell fate.
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Affiliation(s)
- Carlson Tsui
- Lymphocyte Interaction Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | | | - Mauro Gaya
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA
| | - Paula Maldonado
- Lymphocyte Interaction Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Miriam Llorian
- Bioinformatics, The Francis Crick Institute, London NW1 1AT, UK
| | | | - Merja Rossi
- Metabolomics, The Francis Crick Institute, London NW1 1AT, UK
| | - James I MacRae
- Metabolomics, The Francis Crick Institute, London NW1 1AT, UK
| | - Angus J Cameron
- Barts Cancer Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Peter J Parker
- Protein phosphorylation Laboratory, The Francis Crick Institute, London NW1 1AT, UK; School of Cancer and Pharmaceutical Sciences, King's College, London SE1 1UL, UK
| | - Michael Leitges
- Biotechnology Centre of Oslo, University of Oslo, 0349 Oslo, Norway
| | - Andreas Bruckbauer
- Lymphocyte Interaction Laboratory, The Francis Crick Institute, London NW1 1AT, UK; FILM, Imperial College London, London SW7 2BB, UK
| | - Facundo D Batista
- Lymphocyte Interaction Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Ragon Institute of MGH, MIT and Harvard, Cambridge, MA 02139, USA.
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13
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Bod L, Douguet L, Auffray C, Lengagne R, Bekkat F, Rondeau E, Molinier-Frenkel V, Castellano F, Richard Y, Prévost-Blondel A. IL-4-Induced Gene 1: A Negative Immune Checkpoint Controlling B Cell Differentiation and Activation. THE JOURNAL OF IMMUNOLOGY 2017; 200:1027-1038. [PMID: 29288206 DOI: 10.4049/jimmunol.1601609] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/26/2017] [Indexed: 11/19/2022]
Abstract
Emerging data highlight the crucial role of enzymes involved in amino acid metabolism in immune cell biology. IL-4-induced gene-1 (IL4I1), a secreted l-phenylalanine oxidase expressed by APCs, has been detected in B cells, yet its immunoregulatory role has only been explored on T cells. In this study, we show that IL4I1 regulates multiple steps in B cell physiology. Indeed, IL4I1 knockout mice exhibit an accelerated B cell egress from the bone marrow, resulting in the accumulation of peripheral follicular B cells. They also present a higher serum level of natural Igs and self-reactive Abs. We also demonstrate that IL4I1 produced by B cells themselves controls the germinal center reaction, plasma cell differentiation, and specific Ab production in response to T dependent Ags, SRBC, and NP-KLH. In vitro, IL4I1-deficient B cells proliferate more efficiently than their wild-type counterparts in response to BCR cross-linking. Moreover, the absence of IL4I1 increases activation of the Syk-Akt-S6kinase signaling pathway and calcium mobilization, and inhibits SHP-1 activity upon BCR engagement, thus supporting that IL4I1 negatively controls BCR-dependent activation. Overall, our study reveals a new perspective on IL4I1 as a key regulator of B cell biology.
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Affiliation(s)
- Lloyd Bod
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Laetitia Douguet
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Cédric Auffray
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Renée Lengagne
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Fériel Bekkat
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Elena Rondeau
- INSERM, U1016, Institut Cochin, 75014 Paris, France.,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Valérie Molinier-Frenkel
- INSERM, U955, Equipe 09, 94000 Créteil, France.,Faculté de Médecine, Université Paris Est, 94000 Créteil, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Henri Mondor - Albert Chenevier, Service d'Immunologie Biologique, 94000 Créteil, France; and
| | - Flavia Castellano
- INSERM, U955, Equipe 09, 94000 Créteil, France.,Faculté de Médecine, Université Paris Est, 94000 Créteil, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Henri Mondor - Albert Chenevier, Plateforme de Ressources Biologiques, 94000 Créteil, France
| | - Yolande Richard
- INSERM, U1016, Institut Cochin, 75014 Paris, France; .,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Armelle Prévost-Blondel
- INSERM, U1016, Institut Cochin, 75014 Paris, France; .,CNRS, UMR8104, 75014 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
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14
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Ali MF, Dasari H, Van Keulen VP, Carmona EM. Canonical Stimulation of the NLRP3 Inflammasome by Fungal Antigens Links Innate and Adaptive B-Lymphocyte Responses by Modulating IL-1β and IgM Production. Front Immunol 2017; 8:1504. [PMID: 29170665 PMCID: PMC5684107 DOI: 10.3389/fimmu.2017.01504] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/25/2017] [Indexed: 01/02/2023] Open
Abstract
The NLRP3 inflammasome is activated in response to different bacterial, viral, and fungal pathogens and serves as modulator of different pattern recognition receptors signaling pathways. One of the main functions of NLRP3 is to participate in IL-1β maturation which is important in the host defense against Pneumocystis and other fungal infections. However, dysregulation of NLRP3 and IL-1β secretion are also implicated in the pathophysiology of many auto-inflammatory disorders. Often time’s inflammatory flares are preceded by infectious illnesses questioning the role of infection in autoimmune exacerbations. However, we still do not fully understand the exact role that infection or even colonization plays as a trigger of inflammation. Herein, we investigated the role of NLRP3 in circulating B-lymphocytes following activation with two major microbial antigens (β-glucan and CpG). NLRP3 was determined essential in two independent B-lymphocytes processes: pro-inflammatory cytokine secretion and antibody regulation. Our results show that the β-glucan fungal cell wall carbohydrate stimulated B-lymphocytes to secrete IL-1β in a process partially mediated by Dectin-1 activation via SYK and the transcription factors NF-κB and AP-1. This IL-1β secretion was regulated by the NLRP3 inflammasome and was dependent on potassium efflux and Caspase-1. Interestingly, B-lymphocytes activated by unmethylated CpG motifs, found in bacterial and fungal DNA, failed to induce IL-1β. However, B-lymphocyte stimulation by CpG resulted in NLRP3 and Caspase-1 activation and the production and secretion of IgM antibodies. Furthermore, CpG-stimulated IgM secretion, unlike β-glucan-mediated IL-1β production, was mediated by the mammalian target of rapamycin (mTOR). Inhibition of NLRP3 and the mTOR pathway in CpG activated B-lymphocytes resulted in impaired IgM secretion suggesting their participation in antibody regulation. In conclusion, this study describes a differential response of NLRP3 to β-glucan and CpG antigens and identifies the NLRP3 inflammasome of human circulating B-lymphocytes as a modulator of the innate and adaptive immune systems.
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Affiliation(s)
- Mohamed F Ali
- The Thoracic Diseases Research Unit and the Division of Pulmonary and Critical Care, Department of Medicine Mayo Clinic and Foundation, Rochester, MN, United States
| | - Harika Dasari
- The Thoracic Diseases Research Unit and the Division of Pulmonary and Critical Care, Department of Medicine Mayo Clinic and Foundation, Rochester, MN, United States
| | - Virginia P Van Keulen
- The Thoracic Diseases Research Unit and the Division of Pulmonary and Critical Care, Department of Medicine Mayo Clinic and Foundation, Rochester, MN, United States
| | - Eva M Carmona
- The Thoracic Diseases Research Unit and the Division of Pulmonary and Critical Care, Department of Medicine Mayo Clinic and Foundation, Rochester, MN, United States
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15
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mTOR signaling in immune cells and its implications for cancer immunotherapy. Cancer Lett 2017; 408:182-189. [DOI: 10.1016/j.canlet.2017.08.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 02/06/2023]
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16
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Fruman DA, Chiu H, Hopkins BD, Bagrodia S, Cantley LC, Abraham RT. The PI3K Pathway in Human Disease. Cell 2017; 170:605-635. [PMID: 28802037 PMCID: PMC5726441 DOI: 10.1016/j.cell.2017.07.029] [Citation(s) in RCA: 1592] [Impact Index Per Article: 227.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/17/2017] [Accepted: 07/20/2017] [Indexed: 02/08/2023]
Abstract
Phosphoinositide 3-kinase (PI3K) activity is stimulated by diverse oncogenes and growth factor receptors, and elevated PI3K signaling is considered a hallmark of cancer. Many PI3K pathway-targeted therapies have been tested in oncology trials, resulting in regulatory approval of one isoform-selective inhibitor (idelalisib) for treatment of certain blood cancers and a variety of other agents at different stages of development. In parallel to PI3K research by cancer biologists, investigations in other fields have uncovered exciting and often unpredicted roles for PI3K catalytic and regulatory subunits in normal cell function and in disease. Many of these functions impinge upon oncology by influencing the efficacy and toxicity of PI3K-targeted therapies. Here we provide a perspective on the roles of class I PI3Ks in the regulation of cellular metabolism and in immune system functions, two topics closely intertwined with cancer biology. We also discuss recent progress developing PI3K-targeted therapies for treatment of cancer and other diseases.
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Affiliation(s)
- David A Fruman
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA 92697-3900, USA.
| | - Honyin Chiu
- Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, CA 92697-3900, USA
| | - Benjamin D Hopkins
- Meyer Cancer Center, Weill Cornell Medical College, 413 E. 69(th) Street, New York, NY 10021, USA
| | - Shubha Bagrodia
- Oncology R&D Group, Pfizer Worldwide Research and Development, 10646/CB4 Science Center Drive, San Diego, CA 92121, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medical College, 413 E. 69(th) Street, New York, NY 10021, USA
| | - Robert T Abraham
- Oncology R&D Group, Pfizer Worldwide Research and Development, 10646/CB4 Science Center Drive, San Diego, CA 92121, USA
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17
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Li B, Li Z, Wang P, Huang Q, Xu L, He R, Ye L, Bai Q. Mammalian target of rapamycin complex 1 signalling is essential for germinal centre reaction. Immunology 2017; 152:276-286. [PMID: 28557002 DOI: 10.1111/imm.12767] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/04/2017] [Accepted: 05/25/2017] [Indexed: 12/13/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is a serine-threonine kinase that has been shown to be essential for the differentiation and function of various immune cells. Earlier in vitro studies showed that mTOR signalling regulates B-cell biology by supporting their activation and proliferation. However, how mTOR signalling temporally regulates in vivo germinal centre B (GCB) cell development and differentiation into short-lived plasma cells, long-lived plasma cells and memory cells is still not well understood. In this study, we used a combined conditional/inducible knock-out system to investigate the temporal regulation of mTOR complex 1 (mTORC1) in the GCB cell response to acute lymphocytic choriomeningitis virus infection by deleting Raptor, a main component of mTORC1, specifically in B cells in pre- and late GC phase. Early Raptor deficiency strongly inhibited GCB cell proliferation and differentiation and plasma cell differentiation. Nevertheless, late GC Raptor deficiency caused only decreases in the size of memory B cells and long-lived plasma cells through poor maintenance of GCB cells, but it did not change their differentiation. Collectively, our data revealed that mTORC1 signalling supports GCB cell responses at both early and late GC phases during viral infection but does not regulate GCB cell differentiation into memory B cells and plasma cells at the late GC stage.
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Affiliation(s)
- Bingshou Li
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Zhirong Li
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Pengcheng Wang
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Qizhao Huang
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Lifan Xu
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Ran He
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Lilin Ye
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
| | - Qiang Bai
- Institute of Immunology, PLA, Third Military Medical University, Chongqing, China
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18
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Control of B lymphocyte development and functions by the mTOR signaling pathways. Cytokine Growth Factor Rev 2017; 35:47-62. [PMID: 28583723 DOI: 10.1016/j.cytogfr.2017.04.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 04/07/2017] [Indexed: 12/21/2022]
Abstract
Mechanistic target of rapamycin (mTOR) is a serine/threonine kinase originally discovered as the molecular target of the immunosuppressant rapamycin. mTOR forms two compositionally and functionally distinct complexes, mTORC1 and mTORC2, which are crucial for coordinating nutrient, energy, oxygen, and growth factor availability with cellular growth, proliferation, and survival. Recent studies have identified critical, non-redundant roles for mTORC1 and mTORC2 in controlling B cell development, differentiation, and functions, and have highlighted emerging roles of the Folliculin-Fnip protein complex in regulating mTOR and B cell development. In this review, we summarize the basic mechanisms of mTOR signaling; describe what is known about the roles of mTORC1, mTORC2, and the Folliculin/Fnip1 pathway in B cell development and functions; and briefly outline current clinical approaches for targeting mTOR in B cell neoplasms. We conclude by highlighting a few salient questions and future perspectives regarding mTOR in B lineage cells.
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19
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Mohammadian A, Naderali E, Mohammadi SM, Movasaghpour A, Valipour B, Nouri M, Nozad Charoudeh H. Cord Blood Cells Responses to IL2, IL7 and IL15 Cytokines for mTOR Expression. Adv Pharm Bull 2017; 7:81-85. [PMID: 28507940 PMCID: PMC5426737 DOI: 10.15171/apb.2017.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/22/2017] [Accepted: 01/24/2017] [Indexed: 12/12/2022] Open
Abstract
Purpose: Mammalian target of rapamycin (mTOR)is important in hematopoiesis and affect cell growth,differentiation and survival. Although previous studies were identified the effect of cytokines on the mononuclear cells development however the cytokines effect on mTOR in cord blood mononuclear cells was unclear. The aim of this study was to evaluate mTOR expression in cord blood mononuclear and cord blood stem cells (CD34+ cells) in culture conditions for lymphoid cell development. Methods: Isolation of The mononuclear cells (MNCs) from umbilical cord blood were done with use of Ficollpaque density gradient. We evaluated cultured cord blood mononuclear and CD34+ cells in presece of IL2, IL7 and IL15 at distinct time points during 21 days by using flow cytometry. In this study, we presented the role of IL2, IL7 and IL15 on the expression of mTOR in cord blood cells. Results: mTOR expression were increased in peresence of IL2, IL7 and IL15 in day 14 and afterword reduced. However in persence of IL2 and IL15 expression of mTOR significantly reduced. mTOR expression in CD34+ cells decreased significantly from day7 to day 21 in culture. Conclusion: cytokines play important role in mTOR expression during hematopoiesis and development of cord blood mononuclear cells.
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Affiliation(s)
- Anahita Mohammadian
- Stem Cell Research Center, Tabriz university of Medical Sciences, Tabriz, Iran
| | - Elahe Naderali
- Stem Cell Research Center, Tabriz university of Medical Sciences, Tabriz, Iran
| | | | | | - Behnaz Valipour
- Stem Cell Research Center, Tabriz university of Medical Sciences, Tabriz, Iran
| | - Mohammad Nouri
- Stem Cell Research Center, Tabriz university of Medical Sciences, Tabriz, Iran
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20
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Martinez-Martin N, Maldonado P, Gasparrini F, Frederico B, Aggarwal S, Gaya M, Tsui C, Burbage M, Keppler SJ, Montaner B, Jefferies HBJ, Nair U, Zhao YG, Domart MC, Collinson L, Bruckbauer A, Tooze SA, Batista FD. A switch from canonical to noncanonical autophagy shapes B cell responses. Science 2017; 355:641-647. [PMID: 28183981 PMCID: PMC5805088 DOI: 10.1126/science.aal3908] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/13/2017] [Indexed: 11/02/2022]
Abstract
Autophagy is important in a variety of cellular and pathophysiological situations; however, its role in immune responses remains elusive. Here, we show that among B cells, germinal center (GC) cells exhibited the highest rate of autophagy during viral infection. In contrast to mechanistic target of rapamycin complex 1-dependent canonical autophagy, GC B cell autophagy occurred predominantly through a noncanonical pathway. B cell stimulation was sufficient to down-regulate canonical autophagy transiently while triggering noncanonical autophagy. Genetic ablation of WD repeat domain, phosphoinositide-interacting protein 2 in B cells alone enhanced this noncanonical autophagy, resulting in changes of mitochondrial homeostasis and alterations in GC and antibody-secreting cells. Thus, B cell activation prompts a temporal switch from canonical to noncanonical autophagy that is important in controlling B cell differentiation and fate.
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Affiliation(s)
- Nuria Martinez-Martin
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Paula Maldonado
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Francesca Gasparrini
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Bruno Frederico
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Shweta Aggarwal
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Mauro Gaya
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Carlson Tsui
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Marianne Burbage
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Selina Jessica Keppler
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Beatriz Montaner
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Harold B J Jefferies
- Molecular Cell Biology of Autophagy Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Usha Nair
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard University, 400 Technology Square, Cambridge, MA 02139, USA
| | - Yan G Zhao
- Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
| | | | - Lucy Collinson
- Electron Microscopy Unit, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Andreas Bruckbauer
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Sharon A Tooze
- Molecular Cell Biology of Autophagy Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| | - Facundo D Batista
- Lymphocyte Biology Laboratory, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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21
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Kishimoto TK, Ferrari JD, LaMothe RA, Kolte PN, Griset AP, O'Neil C, Chan V, Browning E, Chalishazar A, Kuhlman W, Fu FN, Viseux N, Altreuter DH, Johnston L, Maldonado RA. Improving the efficacy and safety of biologic drugs with tolerogenic nanoparticles. NATURE NANOTECHNOLOGY 2016; 11:890-899. [PMID: 27479756 DOI: 10.1038/nnano.2016.135] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 06/22/2016] [Indexed: 06/06/2023]
Abstract
The development of antidrug antibodies (ADAs) is a common cause for the failure of biotherapeutic treatments and adverse hypersensitivity reactions. Here we demonstrate that poly(lactic-co-glycolic acid) (PLGA) nanoparticles carrying rapamycin, but not free rapamycin, are capable of inducing durable immunological tolerance to co-administered proteins that is characterized by the induction of tolerogenic dendritic cells, an increase in regulatory T cells, a reduction in B cell activation and germinal centre formation, and the inhibition of antigen-specific hypersensitivity reactions. Intravenous co-administration of tolerogenic nanoparticles with pegylated uricase inhibited the formation of ADAs in mice and non-human primates and normalized serum uric acid levels in uricase-deficient mice. Similarly, the subcutaneous co-administration of nanoparticles with adalimumab resulted in the durable inhibition of ADAs, leading to normalized pharmacokinetics of the anti-TNFα antibody and protection against arthritis in TNFα transgenic mice. Adjunct therapy with tolerogenic nanoparticles represents a novel and broadly applicable approach to prevent the formation of ADAs against biologic therapies.
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Affiliation(s)
- Takashi K Kishimoto
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Joseph D Ferrari
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Robert A LaMothe
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Pallavi N Kolte
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Aaron P Griset
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Conlin O'Neil
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Victor Chan
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Erica Browning
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Aditi Chalishazar
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - William Kuhlman
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Fen-Ni Fu
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Nelly Viseux
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - David H Altreuter
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Lloyd Johnston
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
| | - Roberto A Maldonado
- Selecta Biosciences Inc., 480 Arsenal Street, Watertown, Massachusetts 02472, USA
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22
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Zeng H, Cohen S, Guy C, Shrestha S, Neale G, Brown SA, Cloer C, Kishton RJ, Gao X, Youngblood B, Do M, Li MO, Locasale JW, Rathmell JC, Chi H. mTORC1 and mTORC2 Kinase Signaling and Glucose Metabolism Drive Follicular Helper T Cell Differentiation. Immunity 2016; 45:540-554. [PMID: 27637146 PMCID: PMC5050556 DOI: 10.1016/j.immuni.2016.08.017] [Citation(s) in RCA: 257] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 05/25/2016] [Accepted: 06/13/2016] [Indexed: 12/12/2022]
Abstract
Follicular helper T (Tfh) cells are crucial for germinal center (GC) formation and humoral adaptive immunity. Mechanisms underlying Tfh cell differentiation in peripheral and mucosal lymphoid organs are incompletely understood. We report here that mTOR kinase complexes 1 and 2 (mTORC1 and mTORC2) are essential for Tfh cell differentiation and GC reaction under steady state and after antigen immunization and viral infection. Loss of mTORC1 and mTORC2 in T cells exerted distinct effects on Tfh cell signature gene expression, whereas increased mTOR activity promoted Tfh responses. Deficiency of mTORC2 impaired CD4(+) T cell accumulation and immunoglobulin A production and aberrantly induced the transcription factor Foxo1. Mechanistically, the costimulatory molecule ICOS activated mTORC1 and mTORC2 to drive glycolysis and lipogenesis, and glucose transporter 1-mediated glucose metabolism promoted Tfh cell responses. Altogether, mTOR acts as a central node in Tfh cells by linking immune signals to anabolic metabolism and transcriptional activity.
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Affiliation(s)
- Hu Zeng
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sivan Cohen
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Cliff Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sharad Shrestha
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Geoffrey Neale
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Scott A Brown
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Caryn Cloer
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Rigel J Kishton
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Xia Gao
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Ben Youngblood
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Mytrang Do
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ming O Li
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jason W Locasale
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Jeffrey C Rathmell
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA; Department of Pathology, Microbiology, and Immunology, and Center for Immunobiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Hongbo Chi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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Oh B, Yoon J, Farris A, Kirk A, Knechtle S, Kwun J. Rapamycin Interferes With Postdepletion Regulatory T Cell Homeostasis and Enhances DSA Formation Corrected by CTLA4-Ig. Am J Transplant 2016; 16:2612-23. [PMID: 26990829 DOI: 10.1111/ajt.13789] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 03/01/2016] [Accepted: 03/08/2016] [Indexed: 01/25/2023]
Abstract
Previously, we demonstrated that alemtuzumab induction with rapamycin as sole maintenance therapy is associated with an increased incidence of humoral rejection in human kidney transplant patients. To investigate the role of rapamycin in posttransplant humoral responses after T cell depletion, fully MHC mismatched hearts were transplanted into hCD52Tg mice, followed by alemtuzumab treatment with or without a short course of rapamycin. While untreated hCD52Tg recipients acutely rejected B6 hearts (n = 12), hCD52Tg recipients treated with alemtuzumab alone or in conjunction with rapamycin showed a lack of acute rejection (MST > 100). However, additional rapamycin showed a reduced beating quality over time and increased incidence of vasculopathy. Furthermore, rapamycin supplementation showed an increased serum donor-specific antibodies (DSA) level compared to alemtuzumab alone at postoperation days 50 and 100. Surprisingly, additional rapamycin treatment significantly reduced CD4(+) CD25(+) FoxP3(+) T reg cell numbers during treatment. On the contrary, ICOS(+) PD-1(+) CD4 follicular helper T cells in the lymph nodes were significantly increased. Interestingly, CTLA4-Ig supplementation in conjunction with rapamycin corrected rapamycin-induced accelerated posttransplant humoral response by directly modulating Tfh cells but not Treg cells. This suggests that rapamycin after T cell depletion could affect Treg cells leading to an increase of Tfh cells and DSA production that can be reversed by CTLA4-Ig.
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Affiliation(s)
- B Oh
- Emory Transplant Center, Department of Surgery, Emory University School of Medicine, Atlanta, GA
| | - J Yoon
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
| | - A Farris
- Department of Pathology, Emory University School of Medicine, Atlanta, GA
| | - A Kirk
- Emory Transplant Center, Department of Surgery, Emory University School of Medicine, Atlanta, GA.,Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
| | - S Knechtle
- Emory Transplant Center, Department of Surgery, Emory University School of Medicine, Atlanta, GA.,Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
| | - J Kwun
- Emory Transplant Center, Department of Surgery, Emory University School of Medicine, Atlanta, GA.,Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC
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Keating R, McGargill MA. mTOR Regulation of Lymphoid Cells in Immunity to Pathogens. Front Immunol 2016; 7:180. [PMID: 27242787 PMCID: PMC4862984 DOI: 10.3389/fimmu.2016.00180] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 04/25/2016] [Indexed: 12/15/2022] Open
Abstract
Immunity to pathogens exists as a fine balance between promoting activation and expansion of effector cells, while simultaneously limiting normal and aberrant responses. These seemingly opposing functions are kept in check by immune regulators. The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that senses nutrient availability and, in turn, regulates cell metabolism, growth, and survival accordingly. mTOR plays a pivotal role in facilitating immune defense against invading pathogens by regulating the differentiation, activation, and effector functions of lymphoid cells. Here, we focus on the emerging and sometimes contradictory roles of mTOR in orchestrating lymphoid cell-mediated host immune responses to pathogens. A thorough understanding of how mTOR impacts lymphoid cells in pathogen defense will provide the necessary base for developing therapeutic interventions for infectious diseases.
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Affiliation(s)
- Rachael Keating
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
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25
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Petty RD, McCarthy NE, Le Dieu R, Kerr JR. MicroRNAs hsa-miR-99b, hsa-miR-330, hsa-miR-126 and hsa-miR-30c: Potential Diagnostic Biomarkers in Natural Killer (NK) Cells of Patients with Chronic Fatigue Syndrome (CFS)/ Myalgic Encephalomyelitis (ME). PLoS One 2016; 11:e0150904. [PMID: 26967895 PMCID: PMC4788442 DOI: 10.1371/journal.pone.0150904] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 02/22/2016] [Indexed: 01/10/2023] Open
Abstract
Background Chronic Fatigue Syndrome (CFS/ME) is a complex multisystem disease of unknown aetiology which causes debilitating symptoms in up to 1% of the global population. Although a large cohort of genes have been shown to exhibit altered expression in CFS/ME patients, it is currently unknown whether microRNA (miRNA) molecules which regulate gene translation contribute to disease pathogenesis. We hypothesized that changes in microRNA expression in patient leukocytes contribute to CFS/ME pathology, and may therefore represent useful diagnostic biomarkers that can be detected in the peripheral blood of CFS/ME patients. Methods miRNA expression in peripheral blood mononuclear cells (PBMC) from CFS/ME patients and healthy controls was analysed using the Ambion Bioarray V1. miRNA demonstrating differential expression were validated by qRT-PCR and then replicated in fractionated blood leukocyte subsets from an independent patient cohort. The CFS/ME associated miRNA identified by these experiments were then transfected into primary NK cells and gene expression analyses conducted to identify their gene targets. Results Microarray analysis identified differential expression of 34 miRNA, all of which were up-regulated. Four of the 34 miRNA had confirmed expression changes by qRT-PCR. Fractionating PBMC samples by cell type from an independent patient cohort identified changes in miRNA expression in NK-cells, B-cells and monocytes with the most significant abnormalities occurring in NK cells. Transfecting primary NK cells with hsa-miR-99b or hsa-miR-330-3p, resulted in gene expression changes consistent with NK cell activation but diminished cytotoxicity, suggesting that defective NK cell function contributes to CFS/ME pathology. Conclusion This study demonstrates altered microRNA expression in the peripheral blood mononuclear cells of CFS/ME patients, which are potential diagnostic biomarkers. The greatest degree of miRNA deregulation was identified in NK cells with targets consistent with cellular activation and altered effector function.
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Affiliation(s)
- Robert D. Petty
- CFS Group, St George´s University of London, Cranmer Terrace, London, United Kingdom
- Centre for Haemato-Oncology, Bart’s cancer institute, Queen Mary University of London, London, United Kingdom
- * E-mail:
| | - Neil E. McCarthy
- Centre for Immunobiology, The Blizzard institute, Queen Mary University of London, London, United Kingdom
| | - Rifca Le Dieu
- Centre for Haemato-Oncology, Bart’s cancer institute, Queen Mary University of London, London, United Kingdom
| | - Jonathan R. Kerr
- CFS Group, St George´s University of London, Cranmer Terrace, London, United Kingdom
- Grupo de Salud Publica, Escuela de Medicine y Ciencias de la Salud, Universidad del Rosario, Quinta de Mutis, Bogotá 111221, Colombia
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26
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Smith SM, Carew NT, Milcarek C. RNA polymerases in plasma cells trav-ELL2 the beat of a different drum. World J Immunol 2015; 5:99-112. [DOI: 10.5411/wji.v5.i3.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/19/2015] [Accepted: 11/17/2015] [Indexed: 02/05/2023] Open
Abstract
There is a major transformation in gene expression between mature B cells (including follicular, marginal zone, and germinal center cells) and antibody secreting cells (ASCs), i.e., ASCs, (including plasma blasts, splenic plasma cells, and long-lived bone marrow plasma cells). This significant change-over occurs to accommodate the massive amount of secretory-specific immunoglobulin that ASCs make and the export processes itself. It is well known that there is an up-regulation of a small number of ASC-specific transcription factors Prdm1 (B-lymphocyte-induced maturation protein 1), interferon regulatory factor 4, and Xbp1, and the reciprocal down-regulation of Pax5, Bcl6 and Bach2, which maintain the B cell program. Less well appreciated are the major alterations in transcription elongation and RNA processing occurring between B cells and ASCs. The three ELL family members ELL1, 2 and 3 have different protein sequences and potentially distinct cellular roles in transcription elongation. ELL1 is involved in DNA repair and small RNAs while ELL3 was previously described as either testis or stem-cell specific. After B cell stimulation to ASCs, ELL3 levels fall precipitously while ELL1 falls off slightly. ELL2 is induced at least 10-fold in ASCs relative to B cells. All of these changes cause the RNA Polymerase II in ASCs to acquire different properties, leading to differences in RNA processing and histone modifications.
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Differential Effects of Tacrolimus versus Sirolimus on the Proliferation, Activation and Differentiation of Human B Cells. PLoS One 2015; 10:e0129658. [PMID: 26087255 PMCID: PMC4472515 DOI: 10.1371/journal.pone.0129658] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/11/2015] [Indexed: 01/25/2023] Open
Abstract
The direct effect of immunosuppressive drugs calcineurin inhibitor (Tacrolimus, TAC) and mTOR inhibitor (Sirolimus, SRL) on B cell activation, differentiation and proliferation is not well documented. Purified human B cells from healthy volunteers were stimulated through the B Cell Receptor with Anti-IgM + anti-CD40 + IL21 in the absence / presence of TAC or SRL. A variety of parameters of B cell activity including activation, differentiation, cytokine productions and proliferation were monitored by flow cytometry. SRL at clinically relevant concentrations (6 ng/ml) profoundly inhibited CD19+ B cell proliferation compared to controls whereas TAC at similar concentrations had a minimal effect. CD27+ memory B cells were affected more by SRL than naïve CD27- B cells. SRL effectively blocked B cell differentiation into plasma cells (CD19+CD138+ and Blimp1+/Pax5low cells) even at low dose (2 ng/ml), and totally eliminated them at 6 ng/ml. SRL decreased absolute B cell counts, but the residual responding cells acquired an activated phenotype (CD25+/CD69+) and increased the expression of HLA-DR. SRL-treated stimulated B cells on a per cell basis were able to enhance the proliferation of allogeneic CD4+CD25− T cells and induce a shift toward the Th1 phenotype. Thus, SRL and TAC have different effects on B lymphocytes. These data may provide insights into the clinical use of these two agents in recipients of solid organ transplants.
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mTOR kinase inhibitors promote antibody class switching via mTORC2 inhibition. Proc Natl Acad Sci U S A 2014; 111:E5076-85. [PMID: 25385646 DOI: 10.1073/pnas.1407104111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is a kinase that functions in two distinct complexes, mTORC1 and mTORC2. In peripheral B cells, complete deletion of mTOR suppresses germinal center B-cell responses, including class switching and somatic hypermutation. The allosteric mTORC1 inhibitor rapamycin blocks proliferation and differentiation, but lower doses can promote protective IgM responses. To elucidate the complexity of mTOR signaling in B cells further, we used ATP-competitive mTOR kinase inhibitors (TOR-KIs), which inhibit both mTORC1 and mTORC2. Although TOR-KIs are in clinical development for cancer, their effects on mature lymphocytes are largely unknown. We show that high concentrations of TOR-KIs suppress B-cell proliferation and differentiation, yet lower concentrations that preserve proliferation increase the fraction of B cells undergoing class switching in vitro. Transient treatment of mice with the TOR-KI compound AZD8055 increased titers of class-switched high-affinity antibodies to a hapten-protein conjugate. Mechanistic investigation identified opposing roles for mTORC1 and mTORC2 in B-cell differentiation and showed that TOR-KIs enhance class switching in a manner dependent on forkhead box, subgroup O (FoxO) transcription factors. These observations emphasize the distinct actions of TOR-KIs compared with rapamycin and suggest that TOR-KIs might be useful to enhance production of class-switched antibodies following vaccination.
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29
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mTOR activation promotes plasma cell differentiation and bypasses XBP-1 for immunoglobulin secretion. Mol Cell Biol 2014; 35:153-66. [PMID: 25332234 DOI: 10.1128/mcb.01187-14] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Plasma cells (PCs) are responsible for the secretion of antibodies. The development of fully functional PCs relies on the activation of the inositol-requiring enzyme 1/X-box binding protein 1 (IRE1/XBP-1) arm of the unfolded protein response (UPR). XBP-1-deficient PCs secrete antibodies poorly and exhibit distensions of the endoplasmic reticulum (ER). The kinase mammalian target of rapamycin (mTOR) promotes anabolic activities and is negatively regulated by the tuberous sclerosis complex (TSC). Deletion of TSC1 renders mTOR hyperactive. To explore the relationship between mTOR and the UPR in PC development and function, mice with conditional deletions of XBP-1 and/or TSC1 in their B cell lineage were generated. Deletion of TSC1 enhanced Ig synthesis and promoted differentiation into PCs independently of XBP-1, as evidenced by comparison of TSC1/XBP-1 double-knockout (DKO) PCs to XBP-1 knockout (KO) PCs. The typical morphological abnormalities of the ER in XBP-1 KO PCs were alleviated in the DKO PCs. Expression profiling identified the glycoprotein Ly6C as an mTOR target. Ly6C expression contributed to the enhanced Ig secretion from DKO PCs. Our data reveal a functional overlap between mTOR and the UPR in promoting PC development. In addition to the classical mTOR role in promoting protein synthesis, the mechanism entails transcription regulation of accessory molecules, such as Ly6C.
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30
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Zhang Y, Hu T, Hua C, Gu J, Zhang L, Hao S, Liang H, Wang X, Wang W, Xu J, Liu H, Liu B, Cheng T, Yuan W. Rictor is required for early B cell development in bone marrow. PLoS One 2014; 9:e103970. [PMID: 25084011 PMCID: PMC4119011 DOI: 10.1371/journal.pone.0103970] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/03/2014] [Indexed: 11/19/2022] Open
Abstract
The development of early B cells, which are generated from hematopoietic stem cells (HSCs) in a series of well-characterized stages in bone marrow (BM), represents a paradigm for terminal differentiation processes. Akt is primarily regulated by phosphorylation at Thr308 by PDK1 and at Ser473 by mTORC2, and Akt signaling plays a key role in hematopoiesis. However, the role of mTORC2 in the development of early B cells remains poorly understood. In this study, we investigated the functional role of mTORC2 by specifically deleting an integral component, Rictor, in a hematopoietic system. We demonstrated that the deletion of Rictor induced an aberrant increase in the FoxO1 and Rag-1 proteins in BM B cells and that this increase was accompanied by a significant decrease in the abundance of B cells in the peripheral blood (PB) and the spleen, suggesting impaired development of early B cells in adult mouse BM. A BM transplantation assay revealed that the B cell differentiation defect induced by Rictor deletion was not affected by the BM microenvironment, thus indicating a cell-intrinsic mechanism. Furthermore, the knockdown of FoxO1 in Rictor-deleted HSCs and hematopoietic progenitor cells (HPCs) promoted the maturation of B cells in the BM of recipient mice. In addition, we revealed that treatment with rapamycin (an mTORC1 inhibitor) aggravated the deficiency in B cell development in the PB and BM. Taken together, our results provide further evidence that Rictor regulates the development of early B cells in a cell-intrinsic manner by modifying the expression of FoxO1 and Rag-1.
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Affiliation(s)
- Yingchi Zhang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Tianyuan Hu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Chunlan Hua
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Jie Gu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Liyan Zhang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Sha Hao
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Haoyue Liang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaomin Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Weili Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Xu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Hanzhi Liu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Bin Liu
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- 307-Ivy Translational Medicine Center, Laboratory of Oncology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China
| | - Tao Cheng
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
| | - Weiping Yuan
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
- Center for Stem Cell Medicine, Chinese Academy of Medical Sciences, Beijing, China
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Abstract
The mammalian target of rapamycin (mTOR), an essential serine/threonine kinase, functions in biochemically distinct multiprotein complexes, but little is known about roles of the complexes in B cells. The acutely rapamycin-sensitive mTOR complex 1 (mTORC1) is defined by a core subunit Raptor, whereas mTORC2 lacks Raptor and, instead, has Rictor and SIN1 as distinct essential components. We now show that homeostasis and function of B cells require Rictor. Conditional deletion of Rictor before lymphoid specification impaired generation of mature follicular, marginal zone, and B1a B lymphocytes. Induced inactivation in adult mice caused cell-autonomous defects in B lymphoid homeostasis and antibody responses in vivo, along with affecting plasma cells in bone marrow. Survival of B lymphocytes depended on Rictor, which was vital for normal induction of prosurvival genes, suppression of proapoptotic genes, nuclear factor κB induction after B-cell receptor stimulation, and B-cell activating factor-induced nuclear factor κB2/p52 generation. Collectively, the findings provide evidence that mTOR signaling affects survival and proliferation of mature B lymphocytes, and establish Rictor as an important signal relay in B-cell homeostasis, fate, and functions.
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32
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Soliman GA. The role of mechanistic target of rapamycin (mTOR) complexes signaling in the immune responses. Nutrients 2013; 5:2231-57. [PMID: 23783557 PMCID: PMC3725503 DOI: 10.3390/nu5062231] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/05/2013] [Accepted: 06/05/2013] [Indexed: 12/17/2022] Open
Abstract
The mechanistic Target of Rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase which is a member of the PI3K related kinase (PIKK) family. mTOR emerged as a central node in cellular metabolism, cell growth, and differentiation, as well as cancer metabolism. mTOR senses the nutrients, energy, insulin, growth factors, and environmental cues and transmits signals to downstream targets to effectuate the cellular and metabolic response. Recently, mTOR was also implicated in the regulation of both the innate and adaptive immune responses. This paper will summarize the current knowledge of mTOR, as related to the immune microenvironment and immune responses.
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Affiliation(s)
- Ghada A Soliman
- Department of Health Promotion, Social and Behavioral Health Sciences, College of Public Health, University of Nebraska Medical Center, 984365 Nebraska Medical Center, Omaha, NE 68198, USA.
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33
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Abstract
mTOR is an evolutionarily conserved serine/threonine kinase that plays a critical role in cell growth and metabolism by sensing different environmental cues. There is a growing appreciation of mTOR in immunology for its role in integrating diverse signals from the immune microenvironment and coordinating the functions of immune cells and their metabolism. In CD8 T cells, mTOR has shown to influence cellular commitment to effector versus memory programming; in CD4 T cells, mTOR integrates environmental cues that instruct effector cell differentiation. In this review, we summarize and discuss recent advances in the field, with a focus on the mechanisms through which mTOR regulates cellular and humoral immunity. Further understanding will enable the manipulation of mTOR signaling to direct the biological functions of immune cells, which holds great potential for improving immune therapies and vaccination against infections and cancer.
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So L, Yea SS, Oak JS, Lu M, Manmadhan A, Ke QH, Janes MR, Kessler LV, Kucharski JM, Li LS, Martin MB, Ren P, Jessen KA, Liu Y, Rommel C, Fruman DA. Selective inhibition of phosphoinositide 3-kinase p110α preserves lymphocyte function. J Biol Chem 2012; 288:5718-31. [PMID: 23275335 DOI: 10.1074/jbc.m112.379446] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Class IA phosphoinositide 3-kinase (PI3K) is essential for clonal expansion, differentiation, and effector function of B and T lymphocytes. The p110δ catalytic isoform of PI3K is highly expressed in lymphocytes and plays a prominent role in B and T cell responses. Another class IA PI3K catalytic isoform, p110α, is a promising drug target in cancer but little is known about its function in lymphocytes. Here we used highly selective inhibitors to probe the function of p110α in lymphocyte responses in vitro and in vivo. p110α inhibition partially reduced B cell receptor (BCR)-dependent AKT activation and proliferation, and diminished survival supported by the cytokines BAFF and IL-4. Selective p110δ inhibition suppressed B cell responses much more strongly, yet maximal suppression was achieved by targeting multiple PI3K isoforms. In mouse and human T cells, inhibition of single class IA isoforms had little effect on proliferation, whereas pan-class I inhibition did suppress T cell expansion. In mice, selective p110α inhibition using the investigational agent MLN1117 (previously known as INK1117) did not disrupt the marginal zone B cell compartment and did not block T cell-dependent germinal center formation. In contrast, the selective p110δ inhibitor IC87114 strongly suppressed germinal center formation and reduced marginal zone B cell numbers, similar to a pan-class I inhibitor. These findings show that although acute p110α inhibition partially diminishes AKT activation, selective p110α inhibitors are likely to be less immunosuppressive in vivo compared with p110δ or pan-class I inhibitors.
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Affiliation(s)
- Lomon So
- Department of Molecular Biology & Biochemistry, and Institute for Immunology, University of California, Irvine, California 92697, USA
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Blix ES, Irish JM, Husebekk A, Delabie J, Forfang L, Tierens AM, Myklebust JH, Kolstad A. Phospho-specific flow cytometry identifies aberrant signaling in indolent B-cell lymphoma. BMC Cancer 2012; 12:478. [PMID: 23072591 PMCID: PMC3519597 DOI: 10.1186/1471-2407-12-478] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 10/12/2012] [Indexed: 11/10/2022] Open
Abstract
Background Knowledge about signaling pathways in malignant cells may provide prognostic and diagnostic information in addition to identify potential molecular targets for therapy. B-cell receptor (BCR) and co-receptor CD40 signaling is essential for normal B cells, and there is increasing evidence that signaling via BCR and CD40 plays an important role in the pathogenesis of B-cell lymphoma. The aim of this study was to investigate basal and induced signaling in lymphoma B cells and infiltrating T cells in single-cell suspensions of biopsies from small cell lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) and marginal zone lymphoma (MZL) patients. Methods Samples from untreated SLL/CLL and MZL patients were examined for basal and activation induced signaling by phospho-specific flow cytometry. A panel of 9 stimulation conditions targeting B and T cells, including crosslinking of the B cell receptor (BCR), CD40 ligand and interleukins in combination with 12 matching phospho-protein readouts was used to study signaling. Results Malignant B cells from SLL/CLL patients had higher basal levels of phosphorylated (p)-SFKs, p-PLCγ, p-ERK, p-p38, p-p65 (NF-κB), p-STAT5 and p-STAT6, compared to healthy donor B cells. In contrast, anti-BCR induced signaling was highly impaired in SLL/CLL and MZL B cells as determined by low p-SFK, p-SYK and p-PLCγ levels. Impaired anti-BCR-induced p-PLCγ was associated with reduced surface expression of IgM and CD79b. Similarly, CD40L-induced p-ERK and p-p38 were also significantly reduced in lymphoma B cells, whereas p-p65 (NF-κB) was equal to that of normal B cells. In contrast, IL-2, IL-7 and IL-15 induced p-STAT5 in tumor-infiltrating T cells were not different from normal T cells. Conclusions BCR signaling and CD40L-induced p-p38 was suppressed in malignant B cells from SLL/CLL and MZL patients. Single-cell phospho-specific flow cytometry for detection of basal as well as activation-induced phosphorylation of signaling proteins in distinct cell populations can be used to identify aberrant signaling pathways.
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Affiliation(s)
- Egil S Blix
- Department of Oncology, University Hospital of North Norway, Tromsø, Norway.
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Limon JJ, Fruman DA. Akt and mTOR in B Cell Activation and Differentiation. Front Immunol 2012; 3:228. [PMID: 22888331 PMCID: PMC3412259 DOI: 10.3389/fimmu.2012.00228] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/14/2012] [Indexed: 01/08/2023] Open
Abstract
Activation of phosphoinositide 3-kinase (PI3K) is required for B cell proliferation and survival. PI3K signaling also controls key aspects of B cell differentiation. Upon engagement of the B cell receptor (BCR), PI3K activation promotes Ca2+ mobilization and activation of NFκB-dependent transcription, events which are essential for B cell proliferation. PI3K also initiates a distinct signaling pathway involving the Akt and mTOR serine/threonine kinases. It has been generally assumed that activation of Akt and mTOR downstream of PI3K is essential for B cell function. However, Akt and mTOR have complex roles in B cell fate decisions and suppression of this pathway can enhance certain B cell responses while repressing others. In this review we will discuss genetic and pharmacological studies of Akt and mTOR function in normal B cells, and in malignancies of B cell origin.
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Affiliation(s)
- Jose J Limon
- Department of Molecular Biology and Biochemistry, Institute for Immunology, University of California Irvine Irvine, CA, USA
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37
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Poovassery JS, Bishop GA. Type I IFN receptor and the B cell antigen receptor regulate TLR7 responses via distinct molecular mechanisms. THE JOURNAL OF IMMUNOLOGY 2012; 189:1757-64. [PMID: 22786773 DOI: 10.4049/jimmunol.1200624] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Toll-like receptor 7 (TLR7) signals to B cells are critically involved in the innate immune response to microbes, as well as pathogenesis of autoimmune diseases, but the molecular mechanisms that normally regulate these responses are incompletely understood. We previously reported that repeated stimulation through TLR7 induces a state of hyporesponsiveness (TLR tolerance) in both human and mouse B cells, characterized by marked inhibition of particular signaling pathways. BCR signals prevent and overcome TLR7 tolerance. Because optimal responses to TLR7 in B cells require type I IFN, we investigated whether BCR-mediated effects on TLR7 tolerance are mediated by type I IFN receptor (IFNAR) signals. Surprisingly, although BCR-mediated reversal of TLR7 tolerance was IFNAR independent, IFNAR signals alone also blocked TLR7 tolerance, despite enhancing TLR7 expression. Both BCR and IFNAR signals restored the phosphorylation of the transcriptional regulator c-Jun, but only BCR signals blocked the tolerance-mediated inhibition of JNK. Both BCR and IFNAR-mediated regulation was dependent on activation of the PI3K/Akt/mammalian target of rapamycin signaling pathway, indicating a central role for this axis in integrating TLR7, BCR, and IFNAR signals in B cells. These new findings reveal distinct and overlapping signaling mechanisms used by BCR and IFNAR in the regulation of TLR7 tolerance and activation.
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Abstract
Activation of PI3K (phosphoinositide 3-kinase) is a shared response to engagement of diverse types of transmembrane receptors. Depending on the cell type and stimulus, PI3K activation can promote different fates including proliferation, survival, migration and differentiation. The diverse roles of PI3K signalling are well illustrated by studies of lymphocytes, the cells that mediate adaptive immunity. Genetic and pharmacological experiments have shown that PI3K activation regulates many steps in the development, activation and differentiation of both B- and T-cells. These findings have prompted the development of PI3K inhibitors for the treatment of autoimmunity and inflammatory diseases. PI3K activation, however, has both positive and negative roles in immune system activation. Consequently, although PI3K suppression can attenuate immune responses it can also enhance inflammation, disrupt peripheral tolerance and promote autoimmunity. An exciting discovery is that a selective inhibitor of the p110δ catalytic isoform of PI3K, CAL-101, achieves impressive clinical efficacy in certain B-cell malignancies. A model is emerging in which p110δ inhibition disrupts signals from the lymphoid microenvironment, leading to release of leukaemia and lymphoma cells from their protective niche. These encouraging findings have given further momentum to PI3K drug development efforts in both cancer and immune diseases.
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Johnson DS, Chen YH. Ras family of small GTPases in immunity and inflammation. Curr Opin Pharmacol 2012; 12:458-63. [PMID: 22401931 DOI: 10.1016/j.coph.2012.02.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 02/02/2012] [Accepted: 02/03/2012] [Indexed: 11/29/2022]
Abstract
The Ras superfamily of small GTPases is a group of more than 150 small G proteins, all of which share some degree of homology to the founding member Ras. These small GTPases function as molecular switches within cells, impacting nearly all cellular processes. The Ras superfamily can be further divided into several smaller subfamilies, with those proteins that most closely resemble Ras belonging to the Ras subfamily. While heavily studied within the field of cancer biology, the Ras family of proteins also plays cardinal roles in immunity and inflammation. Here we review the roles of these molecular switches in regulating immune cell homeostasis and functions.
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Affiliation(s)
- Derek S Johnson
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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40
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Meyer-Bahlburg A, Rawlings DJ. Differential impact of Toll-like receptor signaling on distinct B cell subpopulations. Front Biosci (Landmark Ed) 2012; 17:1499-516. [PMID: 22201817 DOI: 10.2741/4000] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
B cells exhibit a range of functional responses following TLR engagement including immunoglobulin and cytokine production, proliferation, antigen presentation and migration. However, B cell intrinsic TLR responses appear to be precisely programmed based upon the developmental stage of the cell. B cell subpopulations classified as innate immune cells including marginal zone and B-1 B cells exhibit robust responses to TLR stimulation. In contrast, activation of other B cell subsets is constrained via a variety of developmentally regulated events. In this review we provide an overview of TLR responses in murine and human B cells and specifically highlight patterns of TLR expression and developmentally regulated functional responses.
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Affiliation(s)
- Almut Meyer-Bahlburg
- Department of Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, D-30625 Germany.
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41
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Weichhart T. Mammalian target of rapamycin: a signaling kinase for every aspect of cellular life. Methods Mol Biol 2012; 821:1-14. [PMID: 22125056 DOI: 10.1007/978-1-61779-430-8_1] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mammalian (or mechanistic) target of rapamycin (mTOR) is an evolutionarily conserved serine-threonine kinase that is known to sense the environmental and cellular nutrition and energy status. Diverse mitogens, growth factors, and nutrients stimulate the activation of the two mTOR complexes mTORC1 and mTORC2 to regulate diverse functions, such as cell growth, proliferation, development, memory, longevity, angiogenesis, autophagy, and innate as well as adaptive immune responses. Dysregulation of the mTOR pathway is frequently observed in various cancers and in genetic disorders, such as tuberous sclerosis complex or cystic kidney disease. In this review, I will give an overview of the current understanding of mTOR signaling and its role in diverse tissues and cells. Genetic deletion of specific mTOR pathway proteins in distinct tissues and cells broadened our understanding of the cell-specific roles of mTORC1 and mTORC2. Inhibition of mTOR is an established therapeutic principle in transplantation medicine and in cancers, such as renal cell carcinoma. Pharmacological targeting of both mTOR complexes by novel drugs potentially expand the clinical applicability and efficacy of mTOR inhibition in various disease settings.
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Affiliation(s)
- Thomas Weichhart
- Division of Nephrology and Dialysis, Department of Internal Medicine III, Medical University Vienna, Vienna, Austria.
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42
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Abstract
mTOR is an evolutionarily conserved serine/threonine kinase that plays a central role in integrating environmental cues in the form of growth factors, amino acids, and energy. In the study of the immune system, mTOR is emerging as a critical regulator of immune function because of its role in sensing and integrating cues from the immune microenvironment. With the greater appreciation of cellular metabolism as an important regulator of immune cell function, mTOR is proving to be a vital link between immune function and metabolism. In this review, we discuss the ability of mTOR to direct the adaptive immune response. Specifically, we focus on the role of mTOR in promoting differentiation, activation, and function in T cells, B cells, and antigen-presenting cells.
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Affiliation(s)
- Jonathan D Powell
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA.
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Benhamron S, Tirosh B. Direct activation of mTOR in B lymphocytes confers impairment in B-cell maturation andloss of marginal zone B cells. Eur J Immunol 2011; 41:2390-6. [PMID: 21674478 DOI: 10.1002/eji.201041336] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 04/21/2011] [Accepted: 05/17/2011] [Indexed: 11/06/2022]
Abstract
The tuberous sclerosis complex (TSC), composed of TSC1/TSC2 heterodimers, is inhibitory to the mammalian target of rapamycin (mTOR). Deletion of either TSC1 or TSC2 renders mTOR constitutively active. To directly explore the impact of mTOR activation on B-cell development, we conditionally deleted TSC1 in murine B cells. This led to impairment in B-cell maturation. Unexpectedly, and in contrast to Akt activation, marginal zone (MZ) B cells were significantly reduced. Administration of rapamycin partially corrected the MZ defect, indicating a direct role for mTOR in controlling MZ development. When challenged with a T-cell-dependent antigen, TSC1 KO mice responded less efficiently. Consistent with the MZ defects, TSC1 KO mice did not respond at all to T-independent antigens. Because activation of Akt upstream of TSC and mTOR yields the reverse phenotype with respect to MZ development, we conclude that, physiologically, Akt simultaneously emits two opposing signals that counterbalance each other in the control of B-cell differentiation.
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Affiliation(s)
- Sandrine Benhamron
- Institute for Drug Research, the School of Pharmacy, Hebrew University, Jerusalem, Israel
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Ott PA, Adams S. Small-molecule protein kinase inhibitors and their effects on the immune system: implications for cancer treatment. Immunotherapy 2011; 3:213-27. [PMID: 21322760 DOI: 10.2217/imt.10.99] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Oncogenic signaling pathways have emerged as key targets for the development of small-molecule inhibitors, with several protein kinase inhibitors already in clinical use for cancer patients. In addition to their role in tumorigenesis, many of the molecules and signaling pathways targeted by these inhibitors are also important in the signaling and interaction of immune cells, such as T cells and dendritic cells. Not surprisingly, there is increasing evidence that many of these inhibitors can have a substantial impact on immune function, both stimulating and downregulating an immune response. In order to illustrate the important role of signaling molecule inhibition in the modulation of immune function, we will discuss the exemplary pathways MAPK, AKT-PI3K-mTOR and VEGF-VEGFR, as well as selected small-molecule inhibitors, whose impact on immune cells has been studied more extensively.
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Affiliation(s)
- Patrick A Ott
- New York University Cancer Institute, Division of Medical Oncology, 160 E 34th Street, New York, NY 10016, USA.
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45
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Goldfinger M, Shmuel M, Benhamron S, Tirosh B. Protein synthesis in plasma cells is regulated by crosstalk between endoplasmic reticulum stress and mTOR signaling. Eur J Immunol 2010; 41:491-502. [PMID: 21268018 DOI: 10.1002/eji.201040677] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 10/04/2010] [Accepted: 11/19/2010] [Indexed: 01/22/2023]
Abstract
Plasma cells (PCs) secrete copious levels of immunoglobulins. To achieve this, their endoplasmic reticulum (ER) undergoes expansion in a process that requires continuous ER stress and activation of the unfolded protein response. It is important that protein synthesis, the driver of ER stress, is regulated in a manner that does not induce apoptosis. We followed protein synthesis in murine splenic B cells activated in vitro with LPS. Total protein synthesis levels increased and then steeply decreased when the cells acquired a secretory phenotype. We explored the involvement of two mechanisms in controlling protein synthesis levels, namely ER stress-mediated phosphorylation of eukaryote initiation factor 2α (eIF2α) and the mammalian target of rapamycin (mTOR) pathway, which attenuate or activate mRNA translation, respectively. We show that induction of ER stress in activated B cells counter-intuitively led to dephosphorylation of eIF2α. Despite the reduction in phosphorylated eIF2α, expression of activating transcription factor 4, an effector of hyper eIF2α phosphorylation, was induced. In addition, ER stress attenuated the mTOR pathway, which ultimately reduced protein synthesis. Finally, B cells engineered to overactivate the mTOR pathway exhibited higher apoptosis in the course of LPS stimulation. We conclude that protein synthesis in PCs is controlled by an ER stress-mediated mTOR regulation, which is needed for optimal cell viability.
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Affiliation(s)
- Meidan Goldfinger
- Institute for Drug Research, The School of Pharmacy, The Hebrew University, Jerusalem, Israel
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46
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Constitutive reductions in mTOR alter cell size, immune cell development, and antibody production. Blood 2010; 117:1228-38. [PMID: 21079150 DOI: 10.1182/blood-2010-05-287821] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mammalian TOR (mTOR) regulates cell growth, proliferation, and migration. Because mTOR knock-outs are embryonic lethal, we generated a viable hypomorphic mouse by neo-insertion that partially disrupts mTOR transcription and creates a potential physiologic model of mTORC1/TORC2 inhibition. Homozygous knock-in mice exhibited reductions in body, organ, and cell size. Although reductions in most organ sizes were proportional to decreased body weight, spleens were disproportionately smaller. Decreases in the total number of T cells, particularly memory cells, and reduced responses to chemokines suggested alterations in T-cell homing/homeostasis. T-cell receptor-stimulated T cells proliferated less, produced lower cytokine levels, and expressed FoxP3. Decreased neutrophil numbers were also observed in the spleen, despite normal development and migration in the bone marrow. However, B-cell effects were most pronounced, with a partial block in B-cell development in the bone marrow, altered splenic populations, and decreases in proliferation, antibody production, and migration to chemokines. Moreover, increased AKT(Ser473) phosphorylation was observed in activated B cells, reminiscent of cancers treated with rapamycin, and was reduced by a DNA-pk inhibitor. Thus, mTOR is required for the maturation and differentiation of multiple immune cell lineages. These mice provide a novel platform for studying the consequences of constitutively reduced mTORC1/TORC2 activity.
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47
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Chen J, Limon JJ, Blanc C, Peng SL, Fruman DA. Foxo1 regulates marginal zone B-cell development. Eur J Immunol 2010; 40:1890-6. [PMID: 20449867 DOI: 10.1002/eji.200939817] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A fundamental component of signaling initiated by the BCR and CD19 is the activation of phosphoinositide 3-kinase. Downstream of phosphoinositide 3-kinase, the protein kinase AKT phosphorylates several substrates, including members of the forkhead box subgroup O (Foxo) transcription factor family. Among the Foxo proteins, Foxo1 has unique functions in bone marrow B-cell development and peripheral B-cell function. Here, we report a previously unrecognized role for Foxo1 in controlling the ratio of mature B-cell subsets in the spleen. Conditional deletion of Foxo1 in B cells resulted in an increased percentage of marginal zone B cells and a decrease in follicular (FO) B cells. In addition, Foxo1 deficiency corrected the absence of marginal zone B cells that occurs in CD19-deficient mice. These findings show that Foxo1 regulates the balance of mature B-cell subsets and is required for the marginal zone B-cell deficiency phenotype of mice lacking CD19.
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Affiliation(s)
- Jing Chen
- Department of Molecular Biology & Biochemistry, Institute for Immunology, University of California Irvine, Irvine, CA, USA
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48
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North CM, Crawford RB, Lu H, Kaminski NE. 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated suppression of toll-like receptor stimulated B-lymphocyte activation and initiation of plasmacytic differentiation. Toxicol Sci 2010; 116:99-112. [PMID: 20348231 PMCID: PMC2886857 DOI: 10.1093/toxsci/kfq095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 03/23/2010] [Indexed: 01/20/2023] Open
Abstract
2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD) is a potent suppressor of humoral immunity, disrupting antibody production in response to both T cell-dependent and T cell-independent antigens. Among the cell types required for humoral responses, the B cell is highly, and directly, sensitive to TCDD. B cells become antibody-secreting cells via plasmacytic differentiation, a process regulated by several transcription factors, including activator protein-1, B-cell CLL/lymphoma 6 (BCL-6), and B lymphocyte-induced maturation protein 1 (Blimp-1). The overarching conceptual framework guiding experimentation is that TCDD disrupts plasmacytic differentiation by altering the expression or activity for upstream regulators of Blimp-1. Multiparametric flow cytometry was used to investigate TCDD-induced alterations in both activation marker and transcription factor expression following lipopolysaccharide (LPS) activation of purified B cells. TCDD significantly impaired LPS-activated expression of major histocompatibility complex class II, cluster of differentiation (CD)69, CD80, and CD86. Immunosuppressive concentrations of TCDD also suppressed LPS-activated Blimp-1 and phosphorylated c-Jun expression, whereas elevating BCL-6 expression. Because BCL-6 and c-Jun are directly and indirectly regulated by the kinases AKT, extracellular signal-regulated kinase (ERK), and Jun N-terminal kinase (JNK), it was hypothesized that TCDD alters toll-like receptor-activated kinase phosphorylation. TCDD at 0.03 and 0.3 nM significantly impaired phosphorylation of AKT, ERK, and JNK in CH12.LX B cells activated with LPS, CpG oligonucleotides, or resiquimod (R848). In primary B cells, R848-activated phosphorylation of AKT, ERK, and JNK was also impaired by TCDD at 30 nM. These results suggest that impairment of plasmacytic differentiation by TCDD involves altered transcription factor expression, in part, by suppressed kinase phosphorylation.
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Affiliation(s)
| | | | | | - Norbert E. Kaminski
- Center for Integrative Toxicology, Department of Pharmacology & Toxicology, Michigan State University, East Lansing, Michigan 48824
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49
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Covey TM, Cesano A, Parkinson DR. Single-cell network profiling (SCNP) by flow cytometry in autoimmune disease. Autoimmunity 2010; 43:550-9. [DOI: 10.3109/08916931003674774] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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50
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Okkenhaug K, Fruman DA. PI3Ks in lymphocyte signaling and development. Curr Top Microbiol Immunol 2010; 346:57-85. [PMID: 20563708 DOI: 10.1007/82_2010_45] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Lymphocyte development and function are regulated by tyrosine kinase and G-protein coupled receptors. Each of these classes of receptors activates phosphoinositide 3-kinase (PI3K). In this chapter, we summarize current understanding of how PI3K contributes to key aspects of the adaptive immune system.
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Affiliation(s)
- Klaus Okkenhaug
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK.
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