1
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Schaffer AM, Fiala GJ, Hils M, Natali E, Babrak L, Herr LA, Romero-Mulero MC, Cabezas-Wallscheid N, Rizzi M, Miho E, Schamel WWA, Minguet S. Kidins220 regulates the development of B cells bearing the λ light chain. eLife 2024; 13:e83943. [PMID: 38271217 PMCID: PMC10810608 DOI: 10.7554/elife.83943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/27/2023] [Indexed: 01/27/2024] Open
Abstract
The ratio between κ and λ light chain (LC)-expressing B cells varies considerably between species. We recently identified Kinase D-interacting substrate of 220 kDa (Kidins220) as an interaction partner of the BCR. In vivo ablation of Kidins220 in B cells resulted in a marked reduction of λLC-expressing B cells. Kidins220 knockout B cells fail to open and recombine the genes of the Igl locus, even in genetic scenarios where the Igk genes cannot be rearranged or where the κLC confers autoreactivity. Igk gene recombination and expression in Kidins220-deficient B cells is normal. Kidins220 regulates the development of λLC B cells by enhancing the survival of developing B cells and thereby extending the time-window in which the Igl locus opens and the genes are rearranged and transcribed. Further, our data suggest that Kidins220 guarantees optimal pre-BCR and BCR signaling to induce Igl locus opening and gene recombination during B cell development and receptor editing.
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Affiliation(s)
- Anna-Maria Schaffer
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Signalling Research Centers BIOSS and CIBSS, University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
| | - Gina Jasmin Fiala
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Signalling Research Centers BIOSS and CIBSS, University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
| | - Miriam Hils
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
- Department of Dermatology and Allergy Biederstein, School of Medicine, Technical University of MunichMunichGermany
| | - Eriberto Natali
- Institute of Medical Engineering and Medical Informatics, School of Life Sciences, FHNW 15 University of Applied Sciences and Arts Northwestern SwitzerlandMuttenzSwitzerland
| | - Lmar Babrak
- Institute of Medical Engineering and Medical Informatics, School of Life Sciences, FHNW 15 University of Applied Sciences and Arts Northwestern SwitzerlandMuttenzSwitzerland
| | - Laurenz Alexander Herr
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Signalling Research Centers BIOSS and CIBSS, University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
| | - Mari Carmen Romero-Mulero
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Max Planck Institute of Immunobiology and EpigeneticsFreiburgGermany
| | - Nina Cabezas-Wallscheid
- Max Planck Institute of Immunobiology and EpigeneticsFreiburgGermany
- CIBSS – Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
| | - Marta Rizzi
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
- CIBSS – Centre for Integrative Biological Signalling Studies, University of FreiburgFreiburgGermany
- Division of Clinical and Experimental Immunology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of ViennaViennaAustria
- Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, Faculty of Medicine, University of FreiburgFreiburgGermany
| | - Enkelejda Miho
- Institute of Medical Engineering and Medical Informatics, School of Life Sciences, FHNW 15 University of Applied Sciences and Arts Northwestern SwitzerlandMuttenzSwitzerland
- aiNET GmbHBaselSwitzerland
- SIB Swiss Institute of BioinformaticsLausanneSwitzerland
| | - Wolfgang WA Schamel
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Signalling Research Centers BIOSS and CIBSS, University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
| | - Susana Minguet
- Faculty of Biology, Albert-Ludwigs-University of FreiburgFreiburgGermany
- Signalling Research Centers BIOSS and CIBSS, University of FreiburgFreiburgGermany
- Center of Chronic Immunodeficiency CCI, University Clinics and Medical FacultyFreiburgGermany
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2
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Wemlinger SM, Parker Harp CR, Yu B, Hardy IR, Seefeldt M, Matsuda J, Mingueneau M, Spilker KA, Cameron TO, Larrick JW, Getahun A, Cambier JC. Preclinical Analysis of Candidate Anti-Human CD79 Therapeutic Antibodies Using a Humanized CD79 Mouse Model. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:1566-1584. [PMID: 35321883 PMCID: PMC8976721 DOI: 10.4049/jimmunol.2101056] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/18/2022] [Indexed: 11/19/2022]
Abstract
The BCR comprises a membrane-bound Ig that is noncovalently associated with a heterodimer of CD79A and CD79B. While the BCR Ig component functions to sense extracellular Ag, CD79 subunits contain cytoplasmic ITAMs that mediate intracellular propagation of BCR signals critical for B cell development, survival, and Ag-induced activation. CD79 is therefore an attractive target for Ab and chimeric Ag receptor T cell therapies for autoimmunity and B cell neoplasia. Although the mouse is an attractive model for preclinical testing, due to its well-defined immune system, an obstacle is the lack of cross-reactivity of candidate therapeutic anti-human mAbs with mouse CD79. To overcome this problem, we generated knockin mice in which the extracellular Ig-like domains of CD79A and CD79B were replaced with human equivalents. In this study, we describe the generation and characterization of mice expressing chimeric CD79 and report studies that demonstrate their utility in preclinical analysis of anti-human CD79 therapy. We demonstrate that human and mouse CD79 extracellular domains are functionally interchangeable, and that anti-human CD79 lacking Fc region effector function does not cause significant B cell depletion, but induces 1) decreased expression of plasma membrane-associated IgM and IgD, 2) uncoupling of BCR-induced tyrosine phosphorylation and calcium mobilization, and 3) increased expression of PTEN, consistent with the levels observed in anergic B cells. Finally, anti-human CD79 treatment prevents disease development in two mouse models of autoimmunity. We also present evidence that anti-human CD79 treatment may inhibit Ab secretion by terminally differentiated plasmablasts and plasma cells in vitro.
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Affiliation(s)
- Scott M Wemlinger
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO
| | | | - Bo Yu
- Panorama Research Institute, Sunnyvale, CA
| | | | | | - Jennifer Matsuda
- Department of Biomedical Research, National Jewish Health, Denver, CO; and
| | | | | | | | | | - Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO;
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3
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Genebrier S, Fusaro M, Lambert N, Roullaud S, Millot F, Picard C. A New Missense Mutation in CD79B Leads to Autosomal Recessive Agammaglobulinemia in Two Siblings. J Clin Immunol 2021; 41:1356-1360. [PMID: 33733381 DOI: 10.1007/s10875-021-01022-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022]
Affiliation(s)
- Steve Genebrier
- Study Center for Primary Immunodeficiencies, Necker Hospital for Sick Children - Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Biology Pole, University Hospital, Rennes, France
| | - Mathieu Fusaro
- Study Center for Primary Immunodeficiencies, Necker Hospital for Sick Children - Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- INSERM UMR1163, Imagine Institute, Université de Paris, Paris, France
| | - Nathalie Lambert
- Study Center for Primary Immunodeficiencies, Necker Hospital for Sick Children - Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | | | | | - Capucine Picard
- Study Center for Primary Immunodeficiencies, Necker Hospital for Sick Children - Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
- INSERM UMR1163, Imagine Institute, Université de Paris, Paris, France.
- Pediatric Immuno-Hematology and Rheumatology Unit, Necker Hospital for Sick Children - AP-HP, Paris, France.
- French National Reference Center for Primary Immune Deficiencies CEREDIH, Necker University, Hospital for Sick Children - AP-HP, Paris, France.
- Centre d'Etudes des Déficits Immunitaires (CEDI), Bâtiment Lavoisier, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75015, Paris, France.
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4
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Mahdaviani SA, Rezaei N. Pulmonary Manifestations of Predominantly Antibody Deficiencies. PULMONARY MANIFESTATIONS OF PRIMARY IMMUNODEFICIENCY DISEASES 2019. [PMCID: PMC7123456 DOI: 10.1007/978-3-030-00880-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Predominantly antibody deficiencies (PADs) are the most frequent forms of primary immunodeficiency diseases (PIDs). Commonly accompanied with complications involving several body systems, immunoglobulin substitution therapy along with prophylactic antibiotics remained the cornerstone of treatment for PADs and related complications. Patients with respiratory complications should be prescribed an appropriate therapy as soon as possible and have to be adhering to more and longer medical therapies. Recent studies identified a gap for screening protocols to monitor respiratory manifestations in patients with PADs. In the present chapter, the pulmonary manifestations of different PADs for each have been discussed. The chapter is mainly focused on X-linked agammaglobulinemia, common variable immunodeficiency, activated PI3K-δ syndrome, LRBA deficiency, CD19 complex deficiencies, CD20 deficiency, other monogenic defects associated with hypogammaglobulinemia, immunoglobulin class switch recombination deficiencies affecting B-cells, transient hypogammaglobulinemia of infancy, and selective IgA deficiency.
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Affiliation(s)
- Seyed Alireza Mahdaviani
- Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies Children’s Medical Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran
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5
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Hobeika E, Dautzenberg M, Levit-Zerdoun E, Pelanda R, Reth M. Conditional Selection of B Cells in Mice With an Inducible B Cell Development. Front Immunol 2018; 9:1806. [PMID: 30127788 PMCID: PMC6087743 DOI: 10.3389/fimmu.2018.01806] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/23/2018] [Indexed: 11/13/2022] Open
Abstract
Developing B cells undergo defined maturation steps in the bone marrow and in the spleen. The timing and the factors that control these differentiation steps are not fully understood. By targeting the B cell-restricted mb-1 locus to generate an mb-1 allele that expresses a tamoxifen inducible Cre and another allele in which mb-1 expression can be controlled by Cre, we have established a mouse model with an inducible B cell compartment. With these mice, we studied in detail the kinetics of B cell development and the consequence of BCR activation at a defined B cell maturation stage. Contrary to expectations, transitional 1-B cells exposed to anti-IgM reagents in vivo did not die but instead developed into transitional 2 (T2)-B cells with upregulated Bcl-2 expression. We show, however, that these T2-B cells had an increased dependency on the B cell survival factor B cell activating factor when compared to non-stimulated B cells. Overall, our findings indicate that the inducible mb-1 mouse strain represents a useful model, which allows studying the signals that control the selection of B cells in greater detail.
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Affiliation(s)
- Elias Hobeika
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Marcel Dautzenberg
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Ella Levit-Zerdoun
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,International Max Planck Research School for Molecular and Cellular Biology, Freiburg, Germany
| | - Roberta Pelanda
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Michael Reth
- Centre for Biological Signaling Studies (BIOSS), Biology III, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
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6
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He X, Kläsener K, Iype JM, Becker M, Maity PC, Cavallari M, Nielsen PJ, Yang J, Reth M. Continuous signaling of CD79b and CD19 is required for the fitness of Burkitt lymphoma B cells. EMBO J 2018; 37:e97980. [PMID: 29669863 PMCID: PMC5983214 DOI: 10.15252/embj.201797980] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 02/28/2018] [Accepted: 03/07/2018] [Indexed: 01/05/2023] Open
Abstract
Expression of the B-cell antigen receptor (BCR) is essential not only for the development but also for the maintenance of mature B cells. Similarly, many B-cell lymphomas, including Burkitt lymphoma (BL), require continuous BCR signaling for their tumor growth. This growth is driven by immunoreceptor tyrosine-based activation motif (ITAM) and PI3 kinase (PI3K) signaling. Here, we employ CRISPR/Cas9 to delete BCR and B-cell co-receptor genes in the human BL cell line Ramos. We find that Ramos B cells require the expression of the BCR signaling component Igβ (CD79b), and the co-receptor CD19, for their fitness and competitive growth in culture. Furthermore, we show that in the absence of any other BCR component, Igβ can be expressed on the B-cell surface, where it is found in close proximity to CD19 and signals in an ITAM-dependent manner. These data suggest that Igβ and CD19 are part of an alternative B-cell signaling module that use continuous ITAM/PI3K signaling to promote the survival of B lymphoma and normal B cells.
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Affiliation(s)
- Xiaocui He
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Kathrin Kläsener
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Joseena M Iype
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Martin Becker
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Palash C Maity
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Marco Cavallari
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Peter J Nielsen
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Jianying Yang
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Michael Reth
- BIOSS Centre For Biological Signaling Studies, Department of Molecular Immunology, Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
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7
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Shinohara H, Nagashima T, Cascalho MI, Kurosaki T. TAK1 maintains the survival of immunoglobulin λ-chain-positive B cells. Genes Cells 2016; 21:1233-1243. [PMID: 27696624 DOI: 10.1111/gtc.12442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 09/08/2016] [Indexed: 12/13/2022]
Abstract
TAK1 (MAP3K7) mediation of the IκB kinase (IKK) complex-nuclear factor-κB (NF-κB) pathway is crucial for the activation of immune response and to perpetuate inflammation. Although progress has been made to understand TAK1 function in the B-cell receptor (BCR) signaling, the physiological roles of TAK1 in B-cell development, particularly in the bone marrow (BM), remain elusive. Previous studies suggested that the IKK complex is required for the development of immunoglobulin light chain λ-positive B cells, but not for receptor editing. In contrast, NF-κB activity is suggested to be involved in the regulation of receptor editing. Thus, NF-κB signaling in early B-cell development is yet to be fully characterized. Therefore, we addressed the role of TAK1 in early B-cell development. TAK1-deficient mice showed significant reduction of BM Igλ-positive B-cell numbers without any alteration in the BCR editing. Furthermore, the expression of survival factor Bcl-2 was reduced in TAK1-deficient BM B cells as assessed by microarray and quantitative PCR analyses. Ex vivo over-expression of exogenous Bcl-2 enhanced the survival of TAK1-deficient Igλ-positive B cells. TAK1-IKK-NF-κB signaling contributes to the survival of λ-chain-positive B cells through NF-κB-dependent anti-apoptotic Bcl-2 expression.
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Affiliation(s)
- Hisaaki Shinohara
- Laboratory for Integrated Cellular Systems, RIKEN Center for Integrative Medical Sciences (IMS-RCAI), Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Takeshi Nagashima
- Division of Cell Proliferation, ART, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Marilia I Cascalho
- Department of Surgery, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS-RCAI), Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.,Laboratory for Lymphocyte Differentiation, Immunology Frontier Research Center, Osaka University, 3-1 Yamada-oka, Suita, Osaka, 565-0871, Japan
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8
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Hobeika E, Maity PC, Jumaa H. Control of B Cell Responsiveness by Isotype and Structural Elements of the Antigen Receptor. Trends Immunol 2016; 37:310-320. [PMID: 27052149 DOI: 10.1016/j.it.2016.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/09/2016] [Accepted: 03/13/2016] [Indexed: 01/08/2023]
Abstract
Expression of a functional B cell antigen receptor (BCR) plays a central role in regulating B cell development, maturation, and effector functions. Although IgM is solely expressed in immature B cell stages, the presence of both IgM- and IgD-BCR isotypes on mature naïve B cells raises the question of whether IgD has a unique role in B cell activation and function. While earlier studies suggested a broad functional redundancy between IgM and IgD, recent data point to an important immune regulatory role of IgD. Herein, we review these findings and discuss how the structural flexibility, mode of antigen binding, and co-receptor interactions, enable the IgD-BCR to act as a 'rheostat', regulating the activation and function of mature naïve B cells.
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Affiliation(s)
- Elias Hobeika
- Institute of Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Palash Chandra Maity
- Department of Molecular Immunology, Faculty of Biology, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany; Max-Planck-Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Center for Biological Signaling Studies (BIOSS), Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
| | - Hassan Jumaa
- Institute of Immunology, University Hospital Ulm, 89081 Ulm, Germany; Department of Molecular Immunology, Faculty of Biology, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany.
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9
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Levit-Zerdoun E, Becker M, Pohlmeyer R, Wilhelm I, Maity PC, Rajewsky K, Reth M, Hobeika E. Survival of Igα-Deficient Mature B Cells Requires BAFF-R Function. THE JOURNAL OF IMMUNOLOGY 2016; 196:2348-60. [PMID: 26843325 DOI: 10.4049/jimmunol.1501707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/29/2015] [Indexed: 12/18/2022]
Abstract
Expression of a functional BCR is essential for the development of mature B cells and has been invoked in the control of their maintenance. To test this maintenance function in a new experimental setting, we used the tamoxifen-inducible mb1-CreER(T2) mouse strain to delete or truncate either the mb-1 gene encoding the BCR signaling subunit Igα or the VDJ segment of the IgH (H chain [HC]). In this system, Cre-mediated deletion of the mb-1 gene is accompanied by expression of a GFP reporter. We found that, although the Igα-deficient mature B cells survive for >20 d in vivo, the HC-deficient or Igα tail-truncated B cell population is short-lived, with the HC-deficient cells displaying signs of an unfolded protein response. We also show that Igα-deficient B cells still respond to the prosurvival factor BAFF in culture and require BAFF-R signaling for their in vivo maintenance. These results suggest that, under certain conditions, the loss of the BCR can be tolerated by mature B cells for some time, whereas HC-deficient B cells, potentially generated by aberrant somatic mutations in the germinal center, are rapidly eliminated.
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Affiliation(s)
- Ella Levit-Zerdoun
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Martin Becker
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Roland Pohlmeyer
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Isabel Wilhelm
- Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Palash Chandra Maity
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Klaus Rajewsky
- Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; and
| | - Michael Reth
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany;
| | - Elias Hobeika
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Institute of Immunology, University Hospital Ulm, 89081 Ulm, Germany
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10
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Budzyńska PM, Niemelä M, Sarapulov AV, Kyläniemi MK, Nera KP, Junttila S, Laiho A, Mattila PK, Alinikula J, Lassila O. IRF4 Deficiency Leads to Altered BCR Signalling Revealed by Enhanced PI3K Pathway, Decreased SHIP Expression and Defected Cytoskeletal Responses. Scand J Immunol 2016; 82:418-28. [PMID: 26173778 DOI: 10.1111/sji.12343] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 07/07/2015] [Indexed: 12/13/2022]
Abstract
The graded expression of transcription factor interferon regulatory factor 4 (IRF4) regulates B cell development and is critical for plasma cell differentiation. However, the mechanisms, by which IRF4 elicits its crucial tasks, are largely unknown. To characterize the molecular targets of IRF4 in B cells, we established an IRF4-deficient DT40 B cell line. We found that in the absence of IRF4, the expression of several molecules involved in BCR signalling was altered. For example, the expression of B cell adaptor for PI3K (BCAP) was upregulated, whereas the SHIP (SH2-containing Inositol 5?-Phosphatase) expression was downregulated. These molecular unbalances were accompanied by increased BCR-induced calcium signalling, attenuated B cell linker protein (BLNK) and ERK activity and enhanced activity of PI3K/protein kinase B (Akt) pathway. Further, the IRF4-deficient cells showed dramatically diminished cytoskeletal responses to anti-IgM cross-linking. Our results show that IRF4 has an important role in the regulation of BCR signalling and help to shed light on the molecular mechanisms of B cell development and germinal centre response.
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Affiliation(s)
- P M Budzyńska
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland.,Turku Doctoral Programme of Biomedical Sciences, University of Turku, Turku, Finland
| | - M Niemelä
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
| | - A V Sarapulov
- Institute of Biomedicine, Department of Pathology, University of Turku, Turku, Finland
| | - M K Kyläniemi
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
| | - K-P Nera
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
| | - S Junttila
- The Finnish Microarray and Sequencing Center, Turku Centre for Biotechnology, Turku, Finland
| | - A Laiho
- The Finnish Microarray and Sequencing Center, Turku Centre for Biotechnology, Turku, Finland
| | - P K Mattila
- Institute of Biomedicine, Department of Pathology, University of Turku, Turku, Finland
| | - J Alinikula
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
| | - O Lassila
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
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11
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Zhang BC, Zhang J, Sun L. In-depth profiling and analysis of host and viral microRNAs in Japanese flounder (Paralichthys olivaceus) infected with megalocytivirus reveal involvement of microRNAs in host-virus interaction in teleost fish. BMC Genomics 2014; 15:878. [PMID: 25297525 PMCID: PMC4200114 DOI: 10.1186/1471-2164-15-878] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 09/24/2014] [Indexed: 01/21/2023] Open
Abstract
Background MicroRNAs (miRNAs) regulate gene expression by binding to mRNA transcripts in various biological processes. In mammals and birds, miRNAs are known to play vital parts in both host immune defense and viral infection. However, in lower vertebrates such as teleost, systematic investigations on host and viral miRNAs are lacking. Results In this study, we applied high-throughput sequencing technology to identify and analyze both host and viral miRNAs in Japanese flounder (Paralichthys olivaceus), an economically important teleost fish farmed widely in the world, infected with megalocytivirus at a timescale of 14 days divided into five different time points. The results showed that a total of 381 host miRNAs and 9 viral miRNAs were identified, the latter being all novel miRNAs that have no homologues in the currently available databases. Of the host miRNAs, 251 have been reported previously in flounder and other species, and 130 were discovered for the first time. The expression levels of 121 host miRNAs were significantly altered at 2 d to 14 d post-viral infection (pi), and these miRNAs were therefore classified as differentially expressed host miRNAs. The expression levels of all 9 viral miRNAs increased from 0 d pi to 10 d pi and then dropped from 10 d pi to 14 d pi. For the 121 differentially expressed host miRNAs and the 9 viral miRNAs, 243 and 48 putative target genes, respectively, were predicted in flounder. GO and KEGG enrichment analysis revealed that the putative target genes of both host and viral miRNAs were grouped mainly into the categories of immune response, signal transduction, and apoptotic process. Conclusions The results of our study provide the first evidences that indicate existence in teleost fish (i) infection-responsive host and viral miRNAs that exhibit dynamic changes in expression profiles during the course of viral infection, and (ii) potential involvement of miRNAs in host-viral interaction. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-878) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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12
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Anbazhagan K, Duroux-Richard I, Jorgensen C, Apparailly F. Transcriptomic network support distinct roles of classical and non-classical monocytes in human. Int Rev Immunol 2014; 33:470-89. [PMID: 24730730 DOI: 10.3109/08830185.2014.902453] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Classical and non-classical monocytes are two well-defined subsets of monocytes displaying distinct roles. They differentially express numerous genes relevant to their primary role. Using five independent transcriptomic microarray datasets, we ruled out several inconsistent genes and identified common genes consistently overexpressed either in classical or non-classical monocytes. One hundred and eight genes were significantly increased in classical monocytes and are involved in bacterial defense, inflammation and atherosclerosis. Whereas the 74 genes overexpressed in non-classical monocytes are involved in cytoskeletal dynamics and invasive properties for enhanced motility and infiltration. These signatures unravel the biological functions of monocyte subsets. HIGHLIGHTS We compared five transcriptomic GEO datasets of human monocyte subsets. 108 genes in classical and 74 genes in non-classical monocytes are upregulated. Upregulated genes in classical monocytes support anti-bacterial and inflammatory responses. Upregulated genes in non-classical monocytes support patrolling and infiltration functions.
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13
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Mice with megabase humanization of their immunoglobulin genes generate antibodies as efficiently as normal mice. Proc Natl Acad Sci U S A 2014; 111:5153-8. [PMID: 24706856 DOI: 10.1073/pnas.1324022111] [Citation(s) in RCA: 325] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mice genetically engineered to be humanized for their Ig genes allow for human antibody responses within a mouse background (HumAb mice), providing a valuable platform for the generation of fully human therapeutic antibodies. Unfortunately, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which their genetic humanization was carried out. Heretofore, HumAb mice have been generated by disrupting the endogenous mouse Ig genes and simultaneously introducing human Ig transgenes at a different and random location; KO-plus-transgenic humanization. As we describe in the companion paper, we attempted to make mice that more efficiently use human variable region segments in their humoral responses by precisely replacing 6 Mb of mouse Ig heavy and kappa light variable region germ-line gene segments with their human counterparts while leaving the mouse constant regions intact, using a unique in situ humanization approach. We reasoned the introduced human variable region gene segments would function indistinguishably in their new genetic location, whereas the retained mouse constant regions would allow for optimal interactions and selection of the resulting antibodies within the mouse environment. We show that these mice, termed VelocImmune mice because they were generated using VelociGene technology, efficiently produce human:mouse hybrid antibodies (that are rapidly convertible to fully human antibodies) and have fully functional humoral immune systems indistinguishable from those of WT mice. The efficiency of the VelocImmune approach is confirmed by the rapid progression of 10 different fully human antibodies into human clinical trials.
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14
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Rowland SL, Tuttle K, Torres RM, Pelanda R. Antigen and cytokine receptor signals guide the development of the naïve mature B cell repertoire. Immunol Res 2013; 55:231-40. [PMID: 22941591 DOI: 10.1007/s12026-012-8366-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Immature B cells are generated daily in the bone marrow tissue. More than half of the newly generated immature B cells are autoreactive and bind a self-antigen, while the others are nonautoreactive. A selection process has evolved on the one hand to thwart development of autoreactive immature B cells and, on the other hand, to promote further differentiation of nonautoreactive immature B cells into transitional and mature B cells. These negative and positive selection events are carefully regulated by signals that emanate from the antigen receptor, whether antigen-mediated or tonic, and are influenced by signals that are generated by receptors that bind cytokines, chemokines, and other factors produced in the bone marrow tissue. These signals, therefore, are the predominant driving forces for the generation of a B cell population that is capable of protecting the body from infections while maintaining self-tolerance. Here, we review recent findings from our group and others that describe how tonic antigen receptor signaling and bone marrow cytokines regulate the selection of immature B cells.
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Affiliation(s)
- Sarah L Rowland
- Integrated Department of Immunology, University of Colorado School of Medicine, National Jewish Health, Denver, CO, USA
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15
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Sieger N, Fleischer SJ, Mei HE, Reiter K, Shock A, Burmester GR, Daridon C, Dörner T. CD22 ligation inhibits downstream B cell receptor signaling and Ca(2+) flux upon activation. ACTA ACUST UNITED AC 2013; 65:770-9. [PMID: 23233360 DOI: 10.1002/art.37818] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 11/29/2012] [Indexed: 12/25/2022]
Abstract
OBJECTIVE CD22 is a surface molecule exclusively expressed on B cells that regulates adhesion and B cell receptor (BCR) signaling as an inhibitory coreceptor of the BCR. Central downstream signaling molecules that are activated upon BCR engagement include spleen tyrosine kinase (Syk) and, subsequently, phospholipase Cγ2 (PLCγ2), which results in calcium (Ca(2+)) mobilization. The humanized anti-CD22 monoclonal antibody epratuzumab is currently being tested in clinical trials. This study was undertaken to determine the potential mechanism by which this drug regulates B cell activation. METHODS Purified B cells were preincubated with epratuzumab, and the colocalization of CD22 and CD79α, without BCR engagement, was assessed by confocal microscopy. The phosphorylation of Syk (Y348, Y352) and PLCγ2 (Y759) as well as the Ca(2+) flux in the cells were analyzed by flow cytometry upon stimulation of the BCR and/or Toll-like receptor 9 (TLR-9). The influence of CD22 ligation on BCR signaling was assessed by pretreating the cells with epratuzumab or F(ab')(2) fragment of epratuzumab, in comparison with control cells (medium alone or isotype-matched IgG1). RESULTS Epratuzumab induced colocalization of CD22 and components of the BCR independent of BCR engagement, and also reduced intracellular Ca(2+) mobilization and diminished the phosphorylation of Syk and PLCγ2 after BCR stimulation in vitro. Inhibition of kinase phosphorylation was demonstrated in both CD27- and CD27+ B cells, and this appeared to be independent of Fc receptor signaling. Preactivation of the cells via the stimulation of TLR-9 did not circumvent the inhibitory effect of epratuzumab on BCR signaling. CONCLUSION These findings are consistent with the concept of targeting CD22 to raise the threshold of BCR activation, which could offer therapeutic benefit in patients with autoimmune diseases.
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Affiliation(s)
- N Sieger
- Charité University Medicine Berlin, Berlin, Germany
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16
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Sun B, Mallampati S, Gong Y, Wang D, Lefebvre V, Sun X. Sox4 is required for the survival of pro-B cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:2080-9. [PMID: 23345330 DOI: 10.4049/jimmunol.1202736] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of mature B cells from hematopoietic stem cells is a strictly orchestrated process involving multiple regulatory genes. The transcription factor Sox4 is required for this process, but its role has not been systematically studied, and the underlying mechanisms remain unknown. To determine when and how Sox4 functions in the stepwise process of B cell development, we used mice harboring conditional null alleles for Sox4 and a Cre transgene. Sox4 deletion in hematopoietic stem cells almost entirely eliminated pro-B cells in both fetal livers and adult bone marrow, resulting in a severe deficiency in later stage B cells, including circulating mature B cells. Sox4-deficient pro-B cells, particularly those expressing the stem cell factor receptor c-Kit, readily underwent apoptosis, and even more so when c-Kit activity was inhibited by imatinib. C-Kit-expressing pro-B cells showed decreased activation of the c-Kit downstream protein Src upon Sox4 deletion. Likewise, the level of the anti-apoptotic Bcl2 protein was decreased in residual pro-B cells, and its restoration using a Bcl2 transgene allowed not only partial rescue of pro-B cell survival but also B cell maturation in the absence of Sox4. Our findings indicate that Sox4 is required for the survival of pro-B cells and may functionally interact with c-Kit and Bcl2.
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Affiliation(s)
- Baohua Sun
- Department of Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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17
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Fell Pony syndrome: characterization of developmental hematopoiesis failure and associated gene expression profiles. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:1054-64. [PMID: 22593239 DOI: 10.1128/cvi.00237-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Fell Pony syndrome (FPS) is a fatal immunodeficiency that occurs in foals of the Fell Pony breed. Affected foals present with severe anemia, B cell lymphopenia, and opportunistic infections. Our objective was to conduct a prospective study of potential FPS-affected Fell Pony foals to establish clinical, immunological, and molecular parameters at birth and in the first few weeks of life. Complete blood counts, peripheral blood lymphocyte phenotyping, and serum immunoglobulin concentrations were determined for 3 FPS-affected foals, 49 unaffected foals, and 6 adult horses. In addition, cytology of bone marrow aspirates was performed sequentially in a subset of foals. At birth, the FPS-affected foals were not noticeably ill and had hematocrit and circulating B cell counts comparable to those of unaffected foals; however, over 6 weeks, values for both parameters steadily declined. A bone marrow aspirate from a 3-week-old FPS-affected foal revealed erythroid hyperplasia and concurrent erythroid and myeloid dysplasia, which progressed to a severe erythroid hypoplasia at 5 weeks of life. Immunohistochemical staining confirmed the paucity of B cells in primary and secondary lymphoid tissues. The mRNA expression of genes involved in B cell development, signaling, and maturation was investigated using qualitative and quantitative reverse transcriptase PCR (RT-PCR). Several genes, including CREB1, EP300, MYB, PAX5, and SPI1/PU.1, were sequenced from FPS-affected and unaffected foals. Our study presents evidence of fetal erythrocyte and B cell hematopoiesis with rapid postnatal development of anemia and B lymphopenia in FPS-affected foals. The transition between fetal/neonatal and adult-like hematopoiesis may be an important aspect of the pathogenesis of FPS.
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18
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Hatton O, Martinez OM, Esquivel CO. Emerging therapeutic strategies for Epstein-Barr virus+ post-transplant lymphoproliferative disorder. Pediatr Transplant 2012; 16:220-9. [PMID: 22353174 PMCID: PMC4052840 DOI: 10.1111/j.1399-3046.2012.01656.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
De novo malignancies represent an increasing concern in the transplant population, particularly as long-term graft and patient survival improves. EBV-associated B-cell lymphoma in the setting of PTLD is the leading malignancy in children following solid organ transplantation. Therapeutic strategies can be categorized as pharmacologic, biologic, and cell-based but the variable efficacy of these approaches and the complexity of PTLD suggest that new treatment options are warranted. Here, we review current therapeutic strategies for treatment of PTLD. We also describe the life cycle of EBV, addressing the viral mechanisms that contribute to the genesis and persistence of EBV+ B-cell lymphomas. Specifically, we focus on the oncogenic signaling pathways activated by the EBV LMP1 and LMP2a to understand the underlying mechanisms and mediators of lymphomagenesis with the goal of identifying novel, rational therapeutic targets for the treatment of EBV-associated malignancies.
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Affiliation(s)
- Olivia Hatton
- Program in Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Surgery/Division of Abdominal Transplantation, Stanford University School of Medicine, Stanford, CA, USA
| | - Olivia M. Martinez
- Program in Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Surgery/Division of Abdominal Transplantation, Stanford University School of Medicine, Stanford, CA, USA
| | - Carlos O. Esquivel
- Department of Surgery/Division of Abdominal Transplantation, Stanford University School of Medicine, Stanford, CA, USA
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19
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Hatton O, Phillips LK, Vaysberg M, Hurwich J, Krams SM, Martinez OM. Syk activation of phosphatidylinositol 3-kinase/Akt prevents HtrA2-dependent loss of X-linked inhibitor of apoptosis protein (XIAP) to promote survival of Epstein-Barr virus+ (EBV+) B cell lymphomas. J Biol Chem 2011; 286:37368-78. [PMID: 21908615 DOI: 10.1074/jbc.m111.255125] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
B cell lymphoma survival requires tonic or ligand-independent signals through activation of Syk by the B cell receptor. The Epstein-Barr virus (EBV) protein latent membrane 2a (LMP2a), a mimic of the B cell receptor, provides constitutive survival signals for latently infected cells through Syk activation; however, the precise downstream mechanisms coordinating this survival response in EBV+ B cell lymphomas remain to be elucidated. Herein, we assess the mechanism of Syk survival signaling in EBV+ B cell lymphomas from post-transplant lymphoproliferative disorder (PTLD) to discover virally controlled therapeutic targets involved in lymphomagenesis and tumor progression. Using small molecule inhibition and siRNA strategies, we show that Syk inhibition reduces proliferation and induces apoptosis of PTLD-derived EBV+ B cell lines. Syk inhibition also reduces autocrine IL-10 production. Although Syk inhibition attenuates signaling through both the PI3K/Akt and Erk pathways, only PI3K/Akt inhibition causes apoptosis of PTLD-derived cell lines. Loss of the endogenous caspase inhibitor XIAP is observed after Syk or PI3K/Akt inhibition. The loss of XIAP and apoptosis that results from Syk or PI3K/Akt inhibition is reversed by inhibition of the mitochondrial protease HtrA2. Thus, Syk drives EBV+ B cell lymphoma survival through PI3K/Akt activation, which prevents the HtrA2-dependent loss of XIAP. Syk, Akt, and XIAP antagonists may present potential new therapeutic strategies for PTLD through targeting of EBV-driven survival signals.
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Affiliation(s)
- Olivia Hatton
- Program in Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
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20
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Alinikula J, Kohonen P, Nera KP, Lassila O. Concerted action of Helios and Ikaros controls the expression of the inositol 5-phosphatase SHIP. Eur J Immunol 2010; 40:2599-607. [PMID: 20602434 DOI: 10.1002/eji.200940002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ikaros family transcription factors have a key role in lymphoid development, and their aberrant function contributes to a multitude of lymphoid malignancies. Ikaros and Helios bind to similar DNA sequences, and Helios associates with Ikaros-containing chromatin remodeling complexes. Previously, we have shown that loss of Ikaros leads to diminished BCR-signaling strength. In this study, we describe a Helios-deficient chicken DT40 B-cell line with a BCR signaling phenotype that is the opposite to that of Ikaros-deficient cells. In contrast to Ikaros-deficient cells, Helios(-/-) B cells exhibit increased calcium release to the cytoplasm after BCR crosslinking, but diminished BCR-induced phosphorylation of signaling molecules. The inositol 5-phosphatase SHIP, an important regulator in several signaling pathways, is differentially expressed in Ikaros- and Helios-deficient cells. In the absence of Ikaros, SHIP is upregulated, whereas Helios deficiency leads to the downregulation of SHIP expression. We also show with ChIP that Ikaros binds to the promoter of the INPP5D gene-encoding SHIP. Considering the critical role of SHIP in the BCR signaling pathway, our findings provide insight into the mechanism of how both Helios and Ikaros are involved in the regulation of BCR signaling.
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Affiliation(s)
- Jukka Alinikula
- Turku Graduate School of Biomedical Sciences, University of Turku, Turku, Finland.
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21
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Rowland SL, Leahy KF, Halverson R, Torres RM, Pelanda R. BAFF receptor signaling aids the differentiation of immature B cells into transitional B cells following tonic BCR signaling. THE JOURNAL OF IMMUNOLOGY 2010; 185:4570-81. [PMID: 20861359 DOI: 10.4049/jimmunol.1001708] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BAFF is an important prosurvival cytokine for mature B cells. However, previous studies have shown that BAFFR is already expressed at the immature B cell stage, and that the prosurvival protein Bcl-2 does not completely complement the B cell defects resulting from the absence of BAFFR or BAFF. Thus, we hypothesized that BAFF also functions to aid the differentiation of nonautoreactive immature B cells into transitional B cells and to promote their positive selection. We found that BAFFR is expressed at higher levels on nonautoreactive than on autoreactive immature B cells and that its expression correlates with that of surface IgM and with tonic BCR signaling. Our data indicate that BAFFR signaling enhances the generation of transitional CD23(-) B cells in vitro by increasing cell survival. In vivo, however, BAFFR signaling is dispensable for the generation of CD23(-) transitional B cells in the bone marrow, but it is important for the development of transitional CD23(-) T1 B cells in the spleen. Additionally, we show that BAFF is essential for the differentiation of CD23(-) into CD23(+) transitional B cells both in vitro and in vivo through a mechanism distinct from that mediating cell survival, but requiring tonic BCR signaling. In summary, our data indicate that BAFFR and tonic BCR signals cooperate to enable nonautoreactive immature B cells to differentiate into transitional B cells and to be positively selected into the naive B cell repertoire.
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Affiliation(s)
- Sarah L Rowland
- Integrated Department of Immunology, National Jewish Health and University of Colorado Denver, Denver, CO 80206, USA
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22
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Rowland SL, DePersis CL, Torres RM, Pelanda R. Ras activation of Erk restores impaired tonic BCR signaling and rescues immature B cell differentiation. ACTA ACUST UNITED AC 2010; 207:607-21. [PMID: 20176802 PMCID: PMC2839140 DOI: 10.1084/jem.20091673] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
B cell receptors (BCRs) generate tonic signals critical for B cell survival and early B cell development. To determine whether these signals also mediate the development of transitional and mature B cells, we examined B cell development using a mouse strain in which nonautoreactive immunoglobulin heavy and light chain–targeted B cells express low surface BCR levels. We found that reduced BCR expression translated into diminished tonic BCR signals that strongly impaired the development of transitional and mature B cells. Constitutive expression of Bcl-2 did not rescue the differentiation of BCR-low B cells, suggesting that this defect was not related to decreased cell survival. In contrast, activation of the Ras pathway rescued the differentiation of BCR-low immature B cells both in vitro and in vivo, whereas extracellular signal-regulated kinase (Erk) inhibition impaired the differentiation of normal immature B cells. These results strongly suggest that tonic BCR signaling mediates the differentiation of immature into transitional and mature B cells via activation of Erk, likely through a pathway requiring Ras.
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Affiliation(s)
- Sarah L Rowland
- Integrated Department of Immunology, National Jewish Health and University of Colorado Denver, Denver, CO 80206, USA
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Lacking of Aiolos accelerates pre-mature B cell apoptosis mediated by BCR signaling through elevation in cytochrome c release. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1304-14. [DOI: 10.1016/j.bbamcr.2009.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 04/20/2009] [Accepted: 04/27/2009] [Indexed: 01/12/2023]
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Small TN, Robinson WH, Miklos DB. B cells and transplantation: an educational resource. Biol Blood Marrow Transplant 2009; 15:104-13. [PMID: 19147088 DOI: 10.1016/j.bbmt.2008.10.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Trudy N Small
- Department of Pediatrics and Clinical Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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Bista P, Mele DA, Baez DV, Huber BT. Lymphocyte quiescence factor Dpp2 is transcriptionally activated by KLF2 and TOB1. Mol Immunol 2008; 45:3618-23. [PMID: 18555530 DOI: 10.1016/j.molimm.2008.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 05/05/2008] [Indexed: 12/12/2022]
Abstract
We have shown previously that dipeptidyl peptidase 2 (DPP2) activity is essential for the survival of quiescent, but not activated, lymphocytes. The specific requirement of DPP2 activity for non-dividing cells is indicative of cell cycle specific regulation of this gene product. In the present study, we tested this hypothesis by looking at contact and serum dependence of Dpp2 transcription. We found that transfected promoter-reporter activity, as well as endogenous Dpp2 transcripts, were enhanced in NIH-3T3 cells upon contact-inhibition or serum starvation. Since lung Kruppel-like factor (KLF2), a transcription factor, and TOB1, a transcriptional co-activator, have been shown to be important in maintaining T-lymphocyte quiescence and are both downregulated upon cellular activation, we also looked at the contributions of these factors to Dpp2 transcription. Using a Dpp2 promoter-reporter system, we demonstrate that KLF2 and TOB1 activate the mouse Dpp2 promoter. Finally, we show that in human PBMC, there is a decrease in levels of endogenous DPP2 transcripts upon T cell receptor activation when compared to resting cells. These results demonstrate that Dpp2 transcription is serum and contact-dependent and link two quiescence-specific transcriptional elements to the quiescence-specific requirement of DPP2 enzymatic activity.
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Affiliation(s)
- Pradeep Bista
- Graduate Program in Immunology, Department of Pathology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, United States
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Masciarelli S, Sitia R. Building and operating an antibody factory: redox control during B to plasma cell terminal differentiation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:578-88. [PMID: 18241675 DOI: 10.1016/j.bbamcr.2008.01.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 12/20/2007] [Accepted: 01/04/2008] [Indexed: 01/24/2023]
Abstract
When small B lymphocytes bind their cognate antigens in the context of suitable signals, a dramatic differentiation program is activated that leads to the formation of plasma cells. These are short-lived specialized elements, each capable of secreting several thousands antibodies per second. The massive increase in Ig synthesis and transport entails a dramatic architectural and functional metamorphosis that involves the development of the endoplasmic reticulum (ER) and secretory organelles. Massive Ig secretion poses novel metabolic requirements, particularly for what concerns aminoacid import, ATP synthesis and redox homeostasis. Ig H and L chains enter the ER in the reduced state, to be rapidly oxidised mainly via protein driven relays based on the resident enzymes PDI and Ero1. How do plasma cells cope with the ensuing metabolic and redox stresses? In this essay, we discuss the physiological implications that increased Ig production could have in the control of plasma cell generation, function and lifespan, with emphasis on the potential role of ROS generation in mitochondria and ER.
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Affiliation(s)
- Silvia Masciarelli
- Department of Biology and Technology (DiBiT), San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milano, Italy.
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Kohonen P, Nera KP, Lassila O. Avian model for B-cell immunology--new genomes and phylotranscriptomics. Scand J Immunol 2007; 66:113-21. [PMID: 17635788 DOI: 10.1111/j.1365-3083.2007.01973.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The purpose of this review is to discuss the use of chicken and other model organisms in the study of B-cell development and function as well as to highlight the opportunities afforded by the expanded genome-sequencing efforts. A brief introduction on chicken B-cell biology is followed by discussion of somatic cell reverse genetic approaches using the DT40 cell line. The unique advantages of the DT40 system are emphasized with discussion on B-cell receptor signalling research as well as on DNA repair and mechanisms of immunoglobulin diversification. An attempt is made to compare and contrast the results from chicken with mouse knockouts on the one hand and RNAi with human cell lines on the other. Chicken is also emerging strongly as a platform for gene expression analysis, and avian studies are compared with mammalian studies. Multi-species gene co-expression analysis, which could also be termed phylotranscriptomics, aims to use the evolutionary distance between organisms to its advantage. This approach, still in its infancy, is also reviewed and its applicability to the chicken is discussed.
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Affiliation(s)
- P Kohonen
- Turku Graduate School of Biomedical Sciences, Department of Medical Microbiology, University of Turku, Turku, Finland.
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Narvi E, Nera KP, Terho P, Mustonen L, Granberg J, Lassila O. Aiolos controls gene conversion and cell death in DT40 B cells. Scand J Immunol 2007; 65:503-13. [PMID: 17523942 DOI: 10.1111/j.1365-3083.2007.01929.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Ikaros family transcription factor Aiolos is important for B cell function, since B cells of Aiolos-null mutant mice exhibit an activated phenotype, enhanced B-cell receptor (BCR) signalling response and develop a systemic lupus erythematosus (SLE) type autoimmune disease. Aiolos has also been reported to interact with anti-apoptotic Bcl-2 and Bcl-x(L) in T cells, but whether Aiolos regulates cell death has not been studied in B cells. Here we show that the disruption of Aiolos in the DT40 B cell line induces a cell death sensitive phenotype, as the Aiolos(-/-) cells are more prone to apoptosis by nutritional stress, BCR cross-linking, UV- or gamma-irradiation. Furthermore, the Aiolos(-/-) cells have defective Ig gene conversion providing evidence that Aiolos is needed for the somatic diversification of the BCR repertoire. The re-expression of DNA-binding isoform Aio-1 was able to restore the gene conversion defect of the Aiolos-deficient cells, whereas the introduction of dominant negative isofom Aio-2 had no effect on gene conversion, thus demonstrating the functional importance of alternative splicing within Ikaros family. Although the Aiolos(-/-) cells exhibit reduced expression of activation-induced cytidine deaminase (AID), ectopic AID overexpression did not restore the gene conversion defect in the Aiolos(-/-) cells. Our findings indicate that Aiolos may regulate gene conversion in an AID independent manner.
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Affiliation(s)
- E Narvi
- Turku Graduate School of Biomedical Sciences, University of Turku, Turku, Finland.
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30
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Verkoczy L, Duong B, Skog P, Aït-Azzouzene D, Puri K, Vela JL, Nemazee D. Basal B cell receptor-directed phosphatidylinositol 3-kinase signaling turns off RAGs and promotes B cell-positive selection. THE JOURNAL OF IMMUNOLOGY 2007; 178:6332-41. [PMID: 17475862 PMCID: PMC3777394 DOI: 10.4049/jimmunol.178.10.6332] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PI3K plays key roles in cell growth, differentiation, and survival by generating the second messenger phosphatidylinositol-(3,4,5)-trisphosphate (PIP3). PIP3 activates numerous enzymes, in part by recruiting them from the cytosol to the plasma membrane. We find that in immature B lymphocytes carrying a nonautoreactive Ag receptor, PI3K signaling suppresses RAG expression and promotes developmental progression. Inhibitors of PI3K signaling abrogate this positive selection. Furthermore, immature primary B cells from mice lacking the p85alpha regulatory subunit of PI3K suppress poorly RAG expression, undergo an exaggerated receptor editing response, and, as in BCR-ligated cells, fail to progress into the G1 phase of cell cycle. Moreover, immature B cells carrying an innocuous receptor have sustained elevation of PIP3 levels and activation of the downstream effectors phospholipase C (PLC)gamma2, Akt, and Bruton's tyrosine kinase. Of these, PLCgamma2 appears to play the most significant role in down-regulating RAG expression. It therefore appears that when the BCR of an immature B cell is ligated, PIP3 levels are reduced, PLCgamma2 activation is diminished, and receptor editing is promoted by sustained RAG expression. Taken together, our results provide evidence that PI3K signaling is an important cue required for fostering development of B cells carrying a useful BCR.
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Affiliation(s)
- Laurent Verkoczy
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | - Bao Duong
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
- Kellogg School of Science and Technology Doctoral Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA 92037
| | - Patrick Skog
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
| | | | | | - José Luis Vela
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
- Kellogg School of Science and Technology Doctoral Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA 92037
| | - David Nemazee
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037
- Address correspondence and reprint requests to Dr. David Nemazee, Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, Mail Drop IMM-29, La Jolla, CA 92037.
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31
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Sparwasser T, Eberl G. BAC to immunology--bacterial artificial chromosome-mediated transgenesis for targeting of immune cells. Immunology 2007; 121:308-13. [PMID: 17437533 PMCID: PMC2265958 DOI: 10.1111/j.1365-2567.2007.02605.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Thirty years after the first transgenic mouse was produced, a plethora of genetic tools has been developed to study immune cells in vivo. A powerful development is the bacterial artificial chromosome (BAC) transgenic approach, combining advantages of both conventional transgenic and knock-in gene-targeting strategies. In immunology the potential of BAC transgenic technology has yet to be fully harvested and, combined with a variety of elegant genetic tools, it will allow the analysis of complex immunological processes in vivo. In this short review, we discuss the applications of BACs in immunology, such as identification of regulatory regions, expression and cell-fate mapping, cell ablation, conditional mutations and the generation of humanized mice.
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Affiliation(s)
- Tim Sparwasser
- Institut für Medizinische Mikrobiologie, Immunologie & Hygiene, Technische Universität MünchenMunich, Germany
| | - Gérard Eberl
- Laboratory of Lymphoid Tissue Development, Institut PasteurParis, France
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32
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Abstract
B cells maintain homeostasis by balancing cell viability and cell death. B lymphocytes are susceptible to mitochondria- and receptor-initiated cell death at various stages of peripheral differentiation and during immune responses. The inducible transcription factor NF-kappaB enhances cell viability by activating genes that counteract both cell-death pathways. This review uses characteristic features of NF-kappaB activation and downregulation to provide insight into the regulation of B cell apoptosis in the periphery. In particular, the temporal patterns of NF-kappaB induction, differences between Rel family members, and the intersection between canonical and noncanonical signaling pathways in keeping B cells alive are discussed.
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Affiliation(s)
- Ranjan Sen
- Laboratory of Cellular and Molecular Biology, National Institute on Aging, Baltimore, Maryland 21224, USA.
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33
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Abstract
In adult mammals, bone marrow pluripotent hematopoietic stem cells generate B lymphoid-specified progeny that progress through a series of well-characterized stages before generating B-cell receptor expressing B lymphocytes. These functionally immature B lymphocytes then migrate to the spleen wherein they differentiate through transitional stages into follicular or marginal zone B lymphocytes capable of responding to T-dependent and -independent antigens, respectively. During the terminal stages of B lymphocyte development in the bone marrow, as well as immediately following egress into the peripheral compartments, B lymphocytes are counterselected to eliminate B lymphocytes with potentially dangerous self-reactivity. These developmental and selection events in the bone marrow and periphery are dependent on the integration of intrinsic genetic programs with extrinsic microenvironmental signals that drive progenitors toward increasing B lineage commitment and maturation. This chapter provides a comprehensive overview of the various stages of primary and secondary B lymphocyte development with an emphasis on the selection processes that affect decisions at critical checkpoints. Our intent is to stress the concept that at many steps in the developmental process leading to a mature immunocompetent B lymphocyte, B lineage cells are integrating multiple and different signaling inputs that are translated into specific and appropriate cell fate decisions.
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MESH Headings
- Aging
- Animals
- Antigens, Differentiation, B-Lymphocyte/analysis
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/physiology
- B-Lymphocytes/cytology
- B-Lymphocytes/immunology
- B-Lymphocytes/physiology
- Bone Marrow Cells/cytology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/physiology
- Cell Lineage
- Humans
- Lymphopoiesis/genetics
- Models, Immunological
- Precursor Cells, B-Lymphoid/cytology
- Precursor Cells, B-Lymphoid/immunology
- Precursor Cells, B-Lymphoid/physiology
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Recombination, Genetic
- Signal Transduction
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Affiliation(s)
- John G Monroe
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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34
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Fuentes-Pananá EM, Bannish G, Karnell FG, Treml JF, Monroe JG. Analysis of the Individual Contributions of Igα (CD79a)- and Igβ (CD79b)-Mediated Tonic Signaling for Bone Marrow B Cell Development and Peripheral B Cell Maturation. THE JOURNAL OF IMMUNOLOGY 2006; 177:7913-22. [PMID: 17114463 DOI: 10.4049/jimmunol.177.11.7913] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The individual contribution of Igalpha and Igbeta for BCR-triggered fates is unclear. Prior evidence supports conflicting ideas concerning unique as well as redundant functions for these proteins in the context of BCR/pre-BCR signaling. Part of this ambiguity may reflect the recent appreciation that Igalpha and Igbeta participate in both Ag-independent (tonic) and Ag-dependent signaling. The present study undertook defining the individual requirement for Igalpha and Igbeta under conditions where only ligand-independent tonic signaling was operative. In this regard, we have constructed chimeric proteins containing one or two copies of the cytoplasmic domains of either Igalpha or Igbeta and Igalpha/Igbeta heterodimers with targeted Tyr-->Phe modifications. The ability of these proteins to act as surrogate receptors and trigger early bone marrow and peripheral B cell maturation was tested in RAG2(-/-) primary pro-B cell lines and in gene transfer experiments in the muMT mouse model. We considered that the threshold for a functional activity mediated by the pre-BCR/BCR might only be reached when two functional copies of the Igalpha/Igbeta ITAM domain are expressed together, and therefore the specificity conferred by these proteins can only be observed in these conditions. We found that the ligand-independent tonic signal is sufficient to drive development into mature follicular B cells and both Igalpha and Igbeta chains supported formation of this population. In contrast, neither marginal zone nor B1 mature B cell subsets develop from bone marrow precursors under conditions where only tonic signals are generated.
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Affiliation(s)
- Ezequiel M Fuentes-Pananá
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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35
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Abstract
Studies carried out over the past few years provide strong support for the idea that Ig alpha-Ig beta-containing complexes such as the pre-B-cell receptor and the B-cell receptor can signal independently of ligand engagement, and this has been termed tonic signalling. In this Review, I discuss recent literature that is relevant to the potential mechanisms by which tonic signals are initiated and regulated, and discuss views on how tonic and ligand-dependent (aggregation-mediated) signalling differ. These mechanisms are relevant to the possibility that tonic signals generated through immunoreceptor tyrosine-based activation motif (ITAM)-containing proteins that are expressed by oncogenic viruses induce transformation in non-haematopoietic cells.
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Affiliation(s)
- John G Monroe
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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36
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Nera KP, Alinikula J, Terho P, Narvi E, Törnquist K, Kurosaki T, Buerstedde JM, Lassila O. Ikaros has a crucial role in regulation of B cell receptor signaling. Eur J Immunol 2006; 36:516-25. [PMID: 16482514 DOI: 10.1002/eji.200535418] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The transcription factor Ikaros, a key regulator of hematopoiesis, has an essential role in lymphocyte development. In mice, fetal lymphoid differentiation is blocked in the absence of Ikaros, and whereas T cells develop postnatally, B cells are totally absent. The significance of Ikaros in the B cell development is evident, but how Ikaros regulates B cell function has neither been established nor previously been studied with B cells that lack Ikaros expression. Here we show that disruption of Ikaros in the chicken B cell line DT40 induces a B cell receptor (BCR) signaling defect with reduced phospholipase Cgamma2 phosphorylation and impaired intracellular calcium mobilization, which is restored by Ikaros reintroduction. Furthermore, we show that lack of Ikaros induces hyperphosphorylation of Casitas B lymphoma protein subsequent to BCR activation. These results indicate that the absolute need of Ikaros for development, cell fate decisions and maintenance of B cells is due to the enhancement of BCR signaling.
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Affiliation(s)
- Kalle-Pekka Nera
- Turku Graduate School of Biomedical Sciences, University of Turku, Turku, Finland.
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37
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Pelanda R, Torres RM. Receptor editing for better or for worse. Curr Opin Immunol 2006; 18:184-90. [PMID: 16460922 DOI: 10.1016/j.coi.2006.01.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 01/24/2006] [Indexed: 10/25/2022]
Abstract
Receptor editing has emerged from its original identification as a minor secondary mechanism of B cell tolerance to be considered as a dominant mechanism by which autoreactive immature B cells are rendered tolerant. Clonal deletion, previously regarded as the major mechanism of central B cell tolerance, has been shown by recent studies to operate secondarily and only when receptor editing is unable to provide a non-autoreactive specificity. Receptor editing has also been shown to operate during the development of wild-type B lymphocytes, and ongoing investigations demonstrate the influence of particular signaling molecules in the induction and/or inhibition of receptor editing. Together, these studies begin to map the signaling pathways that regulate receptor editing in autoreactive and non-autoreactive immature B cells.
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Affiliation(s)
- Roberta Pelanda
- Integrated Department of Immunology, National Jewish Medical and Research Center and University of Colorado Health Sciences Center, 1400 Jackson Street, Denver, CO 80206, USA.
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38
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Ng YS, Wardemann H, Chelnis J, Cunningham-Rundles C, Meffre E. Bruton's tyrosine kinase is essential for human B cell tolerance. ACTA ACUST UNITED AC 2004; 200:927-34. [PMID: 15466623 PMCID: PMC2213290 DOI: 10.1084/jem.20040920] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Most polyreactive and antinuclear antibodies are removed from the human antibody repertoire during B cell development. To elucidate how B cell receptor (BCR) signaling may regulate human B cell tolerance, we tested the specificity of recombinant antibodies from single peripheral B cells isolated from patients suffering from X-linked agammaglobulinemia (XLA). These patients carry mutations in the Bruton's tyrosine kinase (BTK) gene that encode an essential BCR signaling component. We find that in the absence of Btk, peripheral B cells show a distinct antibody repertoire consistent with extensive secondary V(D)J recombination. Nevertheless, XLA B cells are enriched in autoreactive clones. Our results demonstrate that Btk is essential in regulating thresholds for human B cell tolerance.
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Affiliation(s)
- Yen-Shing Ng
- Laboratory of Biochemistry and Molecular Immunology, The Hospital for Special Surgery, New York, NY 10021, USA
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39
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Kraus M, Alimzhanov MB, Rajewsky N, Rajewsky K. Survival of resting mature B lymphocytes depends on BCR signaling via the Igalpha/beta heterodimer. Cell 2004; 117:787-800. [PMID: 15186779 DOI: 10.1016/j.cell.2004.05.014] [Citation(s) in RCA: 445] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 04/08/2004] [Accepted: 04/12/2004] [Indexed: 12/19/2022]
Abstract
We previously showed that type I interferon-induced, Cre-mediated ablation of surface BCR expression in mature B cells through Ig-heavy chain deletion results in apoptosis of these cells. This led to the hypothesis that survival signals from the BCR are vital for mature B cells. Here, we test two critical assumptions of this model. First, we demonstrate loss of mature B cells upon induced mutation of a signaling module of the BCR, not precluding BCR surface expression. Second, we show that the cells are also lost upon BCR inactivation in the absence of an exogenous inducer like interferon, excluding that cell death depends on previous cellular activation by the latter. Kinetic data demonstrate that BCR-less mature B cells have a severely reduced lifespan, with a half-life of 3-6 days. Together these results establish that BCR signaling is required to keep resting mature B cells alive in vivo.
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Affiliation(s)
- Manfred Kraus
- New York University, Department of Biology, 1009 Main Building, 100 Washington Square East, New York, NY 10003, USA
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40
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Feng B, Cheng S, Pear WS, Liou HC. NF-kB inhibitor blocks B cell development at two checkpoints. MEDICAL IMMUNOLOGY 2004; 3:1. [PMID: 15050028 PMCID: PMC419369 DOI: 10.1186/1476-9433-3-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Accepted: 03/29/2004] [Indexed: 01/13/2023]
Abstract
Members of the NF-kB transcription factor family are differentially expressed in the B cell lineage. Disruption of individual or two NF-kB subunits exhibits distinct defects in B lymphocyte development, activation, and survival. However, the role each NF-kB plays during B cell development has been obscured by molecular compensation. To address this issue, a trans-dominant form of IkBα was transduced into bone marrow cells to act as a pan-inhibitor of NF-kB using a retroviral system. While the development of T-lymphocytes and myeloid cell lineages was not grossly affected by the transduced IkBα gene, a significant reduction in the number and percentage of B lineage cells was apparent in IkBα transduced chimeric mice. IkBα expression decreased the percentage of pre-B and immature B cell subsets in the bone marrow and further impaired the development of follicular mature B cells and marginal zone B cells in the periphery. Introduction of the Bcl-X transgene completely restored the pre-B and immature B cell pool in the bone marrow. However, despite a significant improvement of overall viability of the B cell lineage, Bcl-X expression was insufficient to overcome the maturation block resulting from NF-kB inhibition. Together, our study suggests that NF-kB activity is required for two distinct checkpoints during B cell development: one is for pre-B/immature B cell viability, the other is to provide both survival and maturation signals to ensure the proper development of follicular mature B cells.
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Affiliation(s)
- Biao Feng
- Division of Immunology, Department of Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Shuhua Cheng
- Division of Immunology, Department of Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Warren S Pear
- Department of Pathology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hsiou-Chi Liou
- Division of Immunology, Department of Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA
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41
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Rosnet O, Blanco-Betancourt C, Grivel K, Richter K, Schiff C. Binding of Free Immunoglobulin Light Chains to VpreB3 Inhibits Their Maturation and Secretion in Chicken B Cells. J Biol Chem 2004; 279:10228-36. [PMID: 14670953 DOI: 10.1074/jbc.m312169-a200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The VpreB3 gene product was first characterized as an immunoglobulin (Ig) mu heavy chain-binding protein in mouse precursor B (pre-B) cells. Although its function is unknown, it has been proposed to participate in the assembly and transport of the pre-B cell receptor. We have identified a VpreB3 orthologous gene in chicken that is located close to the immunoglobulin light chain (LC) gene cluster and specifically expressed in the bursa of Fabricius. By overexpressing VpreB3 in the DT40 IgM(+) immature chicken B cell line, we have characterized VpreB3 as an endoplasmic reticulum-resident glycoprotein that binds preferentially to free IgLC. However, binding to IgHC is observed in IgLC-deficient DT40 cells. Interaction of VpreB3 with free IgLC is partly covalent and induces retention of free IgLC in the endoplasmic reticulum, preventing their secretion without affecting IgM surface expression. Our results demonstrate that this evolutionarily conserved molecule may play a role in the regulation of the maturation and secretion of free IgLC in B cells. We discuss possible implications in the regulation of the immune response.
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MESH Headings
- Amino Acid Sequence
- Animals
- B-Lymphocytes/metabolism
- Cell Line
- Chickens
- DNA, Complementary/metabolism
- Dimerization
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Endoplasmic Reticulum
- Flow Cytometry
- Glycoside Hydrolases/pharmacology
- Golgi Apparatus
- Humans
- Immunoblotting
- Immunoglobulin Light Chains/chemistry
- Immunoglobulin M/chemistry
- Kinetics
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/metabolism
- Mice
- Microscopy, Confocal
- Models, Genetic
- Molecular Sequence Data
- Multigene Family
- Pre-B Cell Receptors
- Precipitin Tests
- Protein Binding
- RNA, Messenger/metabolism
- Receptors, Antigen, B-Cell
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Time Factors
- Tissue Distribution
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Affiliation(s)
- Olivier Rosnet
- Centre d'Immunologie de Marseille-Luminy, Centre National de la Recherche Scientifique-Institut National de la Santé et de la Recherche Médicale-Université de la Méditeranée, Campus de Luminy, 13288 Marseille Cedex 09, France.
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42
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Han A, Saijo K, Mecklenbräuker I, Tarakhovsky A, Nussenzweig MC. Bam32 links the B cell receptor to ERK and JNK and mediates B cell proliferation but not survival. Immunity 2003; 19:621-32. [PMID: 14563325 DOI: 10.1016/s1074-7613(03)00275-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Bam32 is an adaptor protein recruited to the plasma membrane upon B cell receptor (BCR) crosslinking in a phosphoinositol 3-kinase (PI3K)-dependent manner; however, its physiologic function is unclear. To determine its physiologic function, we produced Bam32-deficient mice. Bam32(-/-) B cells develop normally but have impaired T-independent antibody responses in vivo and diminished responses to BCR crosslinking in vitro. Biochemical analysis revealed that Bam32 acts in a novel pathway leading from the BCR to MAPK/ERK Kinases (MEK1/2), MAPK/ERK Kinase Kinase-1 (MEKK1), extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK), but not p38 mitogen-activated protein kinase (p38). This pathway appears to be initiated by hematopoietic progenitor kinase-1 (HPK1), which interacts directly with Bam32, and differs from all previously characterized BCR signaling pathways in that it is required for normal BCR-mediated proliferation but not for B cell survival.
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Affiliation(s)
- Arnold Han
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10021, USA
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43
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Abstract
Recent evidence indicates that B cells are instructed continuously by B-cell receptor (BCR) signals to make crucial cell-fate decisions at several checkpoints during their development. Targeted disruption of BCR signalling components leads to distinct blocks in B-cell maturation, which indicates that key kinases and adaptors fine-tune BCR signalling to direct appropriate cell fates. Recent progress in unravelling the molecular mechanisms of the BCR signalling pathways has helped to clarify how BCR signals regulate the proliferation, survival and apoptosis of developing B cells.
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Affiliation(s)
- Hiroaki Niiro
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA
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