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Costa KMDA, Valente RC, Silva JMCDA, Paiva LSDE, Rumjanek VM. Glucocorticoid susceptibility and in vivo ABCB1 activity differ in murine B cell subsets. AN ACAD BRAS CIENC 2020; 90:3081-3097. [PMID: 30304236 DOI: 10.1590/0001-3765201820180364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/22/2018] [Indexed: 01/09/2023] Open
Abstract
Glucocorticoids are produced and released by the adrenal gland and become elevated in response to stress. Although glucocorticoids are well known for their immunosuppressive effects, less is known about their effects on B cells. ABCB1 is an efflux pump expressed in both cancer and normal cells, modulating the gradient of various metabolites, including hydrocortisone. Our goal was to evaluate the effect of this glucocorticoid on murine B cell differentiation and whether sensitivity to hydrocortisone could be related to ABCB1 activity in vivo. C57BL/6 mice received one or three consecutive i.p. injections of hydrocortisone (70, 140 and 200 mg/kg/day). ABCB1 activity was evaluated via the rhodamine-123 transport and inhibited by cyclosporin A in hydrocortisone-treated and control mice. Cells from bone marrow, spleen and blood were counted, incubated with antibodies and analyzed by flow cytometry. A single hydrocortisone injection did not alter the number of bone marrow subsets. Conversely, three daily injections were able to reduce the cell number of most bone marrow subsets, excepting c-kit-sca-1+ and mature B cells. This treatment reduced marginal zone, follicular and transitional B cells, though splenic subsets were more resistant than bone marrow B cells. Recirculating follicular B cells in the blood were resistant to hydrocortisone. With the exception of follicular B cells, all subpopulations exhibited ABCB1 activity. However, hydrocortisone treatment did not affect ABCB1 activity in most subsets analyzed. Results suggest that hydrocortisone is able to regulate B cell lymphopoiesis although ABCB1 activity is not related to the susceptibility to that glucocorticoid in B cell subsets.
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Affiliation(s)
- Kelli M DA Costa
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Sala H2-03, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil.,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Sala C1-42, 21941-902 Ilha do Fundão, Rio de Janeiro, RJ, Brazil
| | - Raphael C Valente
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Sala H2-03, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil.,Faculdade de Ciências Médicas, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade do Estado do Rio de Janeiro, Av. Prof. Manuel de Abreu 444, 3º andar, Vila Isabel, 20550-170 Rio de Janeiro, RJ, Brazil
| | - Joyle M C DA Silva
- Instituto de Biologia, Departamento de Imunobiologia, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Campus do Valonguinho, Prédio Núcleo de Animais de Laboratório, 2º andar, Laboratório de Imunorregulacão, 24020-141 Niterói, RJ, Brazil
| | - Luciana S DE Paiva
- Instituto de Biologia, Departamento de Imunobiologia, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Campus do Valonguinho, Prédio Núcleo de Animais de Laboratório, 2º andar, Laboratório de Imunorregulacão, 24020-141 Niterói, RJ, Brazil
| | - Vivian M Rumjanek
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, Sala H2-03, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil
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2
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Green AC, Rudolph-Stringer V, Chantry AD, Wu JY, Purton LE. Mesenchymal lineage cells and their importance in B lymphocyte niches. Bone 2019; 119:42-56. [PMID: 29183783 DOI: 10.1016/j.bone.2017.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/21/2017] [Accepted: 11/23/2017] [Indexed: 02/06/2023]
Abstract
Early B lymphopoiesis occurs in the bone marrow and is reliant on interactions with numerous cell types in the bone marrow microenvironment, particularly those of the mesenchymal lineage. Each cellular niche that supports the distinct stages of B lymphopoiesis is unique. Different cell types and signaling molecules are important for the progressive stages of B lymphocyte differentiation. Cells expressing CXCL12 and IL-7 have long been recognized as having essential roles in facilitating progression through stages of B lymphopoiesis. Recently, a number of other factors that extrinsically mediate B lymphopoiesis (positively or negatively) have been identified. In addition, the use of transgenic mouse models to delete specific genes in mesenchymal lineage cells has further contributed to our understanding of how B lymphopoiesis is regulated in the bone marrow. This review will cover the current understanding of B lymphocyte niches in the bone marrow and key extrinsic molecules and signaling pathways involved in these niches, with a focus on how mesenchymal lineage cells regulate B lymphopoiesis.
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Affiliation(s)
- Alanna C Green
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; The University of Melbourne, Department of Medicine at St Vincent's Hospital, Fitzroy, Victoria, Australia; Sheffield Myeloma Research Team, Department of Oncology and Metabolism, The University of Sheffield, Sheffield, UK; The Mellanby Centre for Bone Research, Sheffield, UK.
| | - Victoria Rudolph-Stringer
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; The University of Melbourne, Department of Medicine at St Vincent's Hospital, Fitzroy, Victoria, Australia
| | - Andrew D Chantry
- Sheffield Myeloma Research Team, Department of Oncology and Metabolism, The University of Sheffield, Sheffield, UK; The Mellanby Centre for Bone Research, Sheffield, UK
| | - Joy Y Wu
- Division of Endocrinology, Stanford University School of Medicine, Stanford, CA, USA.
| | - Louise E Purton
- St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia; The University of Melbourne, Department of Medicine at St Vincent's Hospital, Fitzroy, Victoria, Australia.
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3
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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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Winkler TH, Mårtensson IL. The Role of the Pre-B Cell Receptor in B Cell Development, Repertoire Selection, and Tolerance. Front Immunol 2018; 9:2423. [PMID: 30498490 PMCID: PMC6249383 DOI: 10.3389/fimmu.2018.02423] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/01/2018] [Indexed: 11/18/2022] Open
Abstract
Around four decades ago, it had been observed that there were cell lines as well as cells in the fetal liver that expressed antibody μ heavy (μH) chains in the apparent absence of bona fide light chains. It was thus possible that these cells expressed another molecule(s), that assembled with μH chains. The ensuing studies led to the discovery of the pre-B cell receptor (pre-BCR), which is assembled from Ig μH and surrogate light (SL) chains, together with the signaling molecules Igα and β. It is expressed on a fraction of pro-B (pre-BI) cells and most large pre-B(II) cells, and has been implicated in IgH chain allelic exclusion and down-regulation of the recombination machinery, assessment of the expressed μH chains and shaping the IgH repertoire, transition from the pro-B to pre-B stage, pre-B cell expansion, and cessation.
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Affiliation(s)
- Thomas H Winkler
- Chair of Genetics, Department of Biology, Nikolaus-Fiebiger-Center for Molecular Medicine, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Inga-Lill Mårtensson
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Sigvardsson M. Molecular Regulation of Differentiation in Early B-Lymphocyte Development. Int J Mol Sci 2018; 19:ijms19071928. [PMID: 29966360 PMCID: PMC6073616 DOI: 10.3390/ijms19071928] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 12/15/2022] Open
Abstract
B-lymphocyte differentiation is one of the best understood developmental pathways in the hematopoietic system. Our understanding of the developmental trajectories linking the multipotent hematopoietic stem cell to the mature functional B-lymphocyte is extensive as a result of efforts to identify and prospectively isolate progenitors at defined maturation stages. The identification of defined progenitor compartments has been instrumental for the resolution of the molecular features that defines given developmental stages as well as for our understanding of the mechanisms that drive the progressive maturation process. Over the last years it has become increasingly clear that the regulatory networks that control normal B-cell differentiation are targeted by mutations in human B-lineage malignancies. This generates a most interesting link between development and disease that can be explored to improve diagnosis and treatment protocols in lymphoid malignancies. The aim of this review is to provide an overview of our current understanding of molecular regulation in normal and malignant B-cell development.
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Affiliation(s)
- Mikael Sigvardsson
- Division of Molecular Hematology, Lund Stem Cell Center, Department of Laboratory Medicine, Lund University, 22184 Lund, Sweden.
- Department of Clinical and Experimental Medicine, Linköping University, SE-581 85 Linköping, Sweden.
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Distorted antibody repertoire developed in the absence of pre-B cell receptor formation. Biochem Biophys Res Commun 2017; 495:1411-1417. [PMID: 29191653 DOI: 10.1016/j.bbrc.2017.11.171] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 11/25/2017] [Indexed: 11/22/2022]
Abstract
The pre-B cell receptor (pre-BCR), consisting of the μ heavy chain (μHC) and the surrogate light chain (SLC, Vpre-B and λ5), plays important roles during B cell development. The formation of the pre-BCR, which enables the nascent immunoglobulin HC to associate with the SLC, is considered a prerequisite for B cell development. However, a significant number of peripheral mature (leaky) B cells exist in SLC-deficient mice. These leaky B cells develop in the absence of pre-BCR and do not undergo the pre-BCR checkpoint. The antibody repertoires of leaky B cells thus reflect the absence of pre-BCR function. To investigate how the absence of the pre-BCR is circumvented by these leaky-B cells and examine the effect of the pre-BCR checkpoint on the antibody system, we analyzed the antibody repertoires of λ5-deficient (λ5-/-) mice using next-generation sequencing. In λ5-/- mice, spleen B cells displayed different patterns of VDJ-usage, relative to those in wild-type (WT) mice. Moreover, leaky B cells were neither derived from unusual B2 cells, characterized by particular LC gene rearrangements in the absence of pre-BCR signaling, nor from B1 cells, originating from different B cell progenitors. Analysis of the CDR-H3 amino acid sequences of μ-chain repertoires revealed that certain bone marrow B cells with particular CDR-H3 profiles undergo clonal expansion in λ5-/- mice. Part of these CDR-H3s contain arginine(s) in the middle of the CDR-H3 loop in λ5-/- mice, whereas few arginine(s) exist in this middle loop in WT CDR-H3s in the absence of clonal expansion. This CDR-H3 feature in λ5-/- mice presumably reflects the role of the pre-BCR in autoantibody regulation, since arginine(s) are often found in the antigen-binding site of autoantibodies. Here, we present a unique viewpoint on the role of pre-BCR, by assessing the whole antibody repertoire formed in SLC-deficient mice.
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Bone Marrow-Derived Stem Cell Populations Are Differentially Regulated by Thyroid or/and Ovarian Hormone Loss. Int J Mol Sci 2017; 18:ijms18102139. [PMID: 29048335 PMCID: PMC5666821 DOI: 10.3390/ijms18102139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 09/19/2017] [Accepted: 09/28/2017] [Indexed: 02/08/2023] Open
Abstract
Bone marrow-derived stem cells (BMDSCs) play an essential role in organ repair and regeneration. The molecular mechanisms by which hormones control BMDSCs proliferation and differentiation are unclear. Our aim in this study was to investigate how a lack of ovarian or/and thyroid hormones affects stem cell number in bone marrow lineage. To examine the effect of thyroid or/and ovarian hormones on the proliferative activity of BMDSCs, we removed the thyroid or/and the ovaries of adult female rats. An absence of ovarian and thyroid hormones was confirmed by Pap staining and Thyroid Stimulating Hormone (TSH) measurement, respectively. To obtain the stem cells from the bone marrow, we punctured the iliac crest, and aspirated and isolated cells by using a density gradient. Specific markers were used by cytometry to identify the different BMDSCs types: endothelial progenitor cells (EPCs), precursor B cells/pro-B cells, and mesenchymal stem cells (MSCs). Interestingly, our results showed that hypothyroidism caused a significant increase in the percentage of EPCs, whereas a lack of ovarian hormones significantly increased the precursor B cells/pro-B cells. Moreover, the removal of both glands led to increased MSCs. In conclusion, both ovarian and thyroid hormones appear to have key and diverse roles in regulating the proliferation of cells populations of the bone marrow.
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8
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Deacetylase activity of histone deacetylase 3 is required for productive VDJ recombination and B-cell development. Proc Natl Acad Sci U S A 2017; 114:8608-8613. [PMID: 28739911 DOI: 10.1073/pnas.1701610114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Histone deacetylase 3 (HDAC3) is the catalytic component of NCoR/SMRT corepressor complexes that mediate the actions of transcription factors implicated in the regulation of B-cell development and function. We crossed Hdac3 conditional knockout mice with Mb1-Cre knockin animals to delete Hdac3 in early progenitor B cells. The spleens of Hdac3F/-Mb1-Cre+/- mice were virtually devoid of mature B cells, and B220+CD43+ B-cell progenitors accumulated within the bone marrow. Quantitative deep sequencing of the Ig heavy chain locus from B220+CD43+ populations identified a defect in VHDJH recombination with a severe reduction in productive rearrangements, which directly corresponded to the loss of pre-B cells from Hdac3Δ/- bone marrow. For Hdac3Δ/- B cells that did show productive VDJ rearrangement, there was significant skewing toward the incorporation of proximal VH gene segments and a corresponding reduction in distal VH gene segment use. Although transcriptional effects within these loci were modest, Hdac3Δ/- progenitor cells displayed global changes in chromatin structure that likely hindered effective distal V-DJ recombination. Reintroduction of wild-type Hdac3 restored normal B-cell development, whereas an Hdac3 point mutant lacking deacetylase activity failed to complement this defect. Thus, the deacetylase activity of Hdac3 is required for the generation of mature B cells.
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9
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Adler LN, Jiang W, Bhamidipati K, Millican M, Macaubas C, Hung SC, Mellins ED. The Other Function: Class II-Restricted Antigen Presentation by B Cells. Front Immunol 2017; 8:319. [PMID: 28386257 PMCID: PMC5362600 DOI: 10.3389/fimmu.2017.00319] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/07/2017] [Indexed: 12/31/2022] Open
Abstract
Mature B lymphocytes (B cells) recognize antigens using their B cell receptor (BCR) and are activated to become antibody-producing cells. In addition, and integral to the development of a high-affinity antibodies, B cells utilize the specialized major histocompatibility complex class II (MHCII) antigen presentation pathway to process BCR-bound and internalized protein antigens and present selected peptides in complex with MHCII to CD4+ T cells. This interaction influences the fate of both types of lymphocytes and shapes immune outcomes. Specific, effective, and optimally timed antigen presentation by B cells requires well-controlled intracellular machinery, often regulated by the combined effects of several molecular events. Here, we delineate and summarize these events in four steps along the antigen presentation pathway: (1) antigen capture and uptake by B cells; (2) intersection of internalized antigen/BCRs complexes with MHCII in peptide-loading compartments; (3) generation and regulation of MHCII/peptide complexes; and (4) exocytic transport for presentation of MHCII/peptide complexes at the surface of B cells. Finally, we discuss modulation of the MHCII presentation pathway across B cell development and maturation to effector cells, with an emphasis on the shaping of the MHCII/peptide repertoire by two key antigen presentation regulators in B cells: HLA-DM and HLA-DO.
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Affiliation(s)
- Lital N Adler
- Department of Pediatrics, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA
| | - Wei Jiang
- Department of Pediatrics, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA
| | | | | | - Claudia Macaubas
- Department of Pediatrics, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA
| | - Shu-Chen Hung
- Department of Pediatrics, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA
| | - Elizabeth D Mellins
- Department of Pediatrics, Stanford University, Stanford, CA, USA; Program in Immunology, Stanford University, Stanford, CA, USA
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10
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Constitutive Kit activity triggers B-cell acute lymphoblastic leukemia-like disease in mice. Exp Hematol 2016; 45:45-55.e6. [PMID: 27664314 DOI: 10.1016/j.exphem.2016.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 08/17/2016] [Accepted: 09/14/2016] [Indexed: 11/21/2022]
Abstract
Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and, in most cases, is of pro- or pre-B cell origin (B-ALL). The receptor tyrosine kinase KIT is expressed by hematopoietic stem and precursor cells. Gain-of-function mutations of KIT cause systemic mastocytosis, which is characterized by abnormal accumulations of mast cells. We previously reported a mouse model of mastocytosis based on conditional expression of a constitutively active Kit protein. Half of these animals developed leukemic disease of B-lineage origin. Herein, we report that this condition bears striking similarities to human B-ALL. The immuno-phenotype of the leukemic cells was compatible with a pro-B-cell origin, as was the finding of immunoglobulin heavy-chain gene rearrangements in all cases, whereas light-chain loci were mostly not rearranged. Leukemogenesis was independent of pre-B-cell receptor expression. Primary leukemic cells and permanent cell lines derived from these were serially transplantable and rapidly killed the recipients. In a few animals, the leukemia was of T-cell origin with abnormal CD4/8 double-positive T-cell precursors dominating in the circulation. In summary, we report a novel ALL mouse model that may prove useful for in vivo drug testing and identification of novel oncogenic mutations and principles.
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Rosenbaum M, Andreani V, Kapoor T, Herp S, Flach H, Duchniewicz M, Grosschedl R. MZB1 is a GRP94 cochaperone that enables proper immunoglobulin heavy chain biosynthesis upon ER stress. Genes Dev 2014; 28:1165-78. [PMID: 24888588 PMCID: PMC4052763 DOI: 10.1101/gad.240762.114] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
MZB1 (pERp1) is a B-cell-specific and endoplasmic reticulum (ER)-localized protein implicated in antibody secretion and integrin-mediated cell adhesion. Rosenbaum et al. discovered that MZB1 deletion impairs humoral immune responses and antibody secretion in plasma cells that naturally undergo ER stress. Experimental induction of ER stress in mice results in a block of pro-B-cell to pre-B-cell differentiation in Mzb1 knockout mice. MZB1 associates directly with GRP94 and is required for the interaction of GRP94 with immunoglobulin µ heavy chains upon ER stress. MZB1 (pERp1) is a B-cell-specific and endoplasmic reticulum (ER)-localized protein implicated in antibody secretion and integrin-mediated cell adhesion. Here, we examine the role of MZB1 in vivo by conditional gene inactivation in the mouse germline and at different stages of B lymphopoiesis. Deletion of MZB1 impairs humoral immune responses and antibody secretion in plasma cells that naturally undergo ER stress. In addition, we found that experimental induction of ER stress by tunicamycin injections in mice results in a block of pro-B-cell to pre-B-cell differentiation specifically in Mzb1−/− mice. A similar developmental block was observed in Mzb1fl/flmb1Cre mice, whereby a Cre recombinase-induced genotoxic stress unmasks a role for MZB1 in the surface expression of immunoglobulin µ heavy chains (µHCs). MZB1 associates directly with the substrate-specific chaperone GRP94 (also called HSP90B1 or gp96) in an ATP-sensitive manner and is required for the interaction of GRP94 with µHCs upon ER stress. Thus, MZB1 seems to act as a substrate-specific cochaperone of GRP94 that enables proper biosynthesis of µHCs under conditions of ER stress.
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Affiliation(s)
- Marc Rosenbaum
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Virginia Andreani
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Tanya Kapoor
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Simone Herp
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Henrik Flach
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Marlena Duchniewicz
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Rudolf Grosschedl
- Department of Cellular and Molecular Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
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Abstract
The development and function of B lymphocytes critically depend on the non-germline B-cell antigen receptor (BCR). In addition to the diverse antigen-recognition regions, whose coding sequences are generated by the somatic DNA rearrangement, the variety of the constant domains of the Heavy Chain (HC) portion contributes to the multiplicity of the BCR types. The functions of particular classes of the HC, particularly in the context of the membrane BCR, are not completely understood. The expression of the various classes of the HC correlates with the distinct stages of B-cell development, types of B-cell subsets, and their effector functions. In this chapter, we summarize and discuss the accumulated knowledge on the role of the μ, δ, and γ HC isotypes of the conventional and precursor BCR in B-cell differentiation, selection, and engagement with (auto)antigens.
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Affiliation(s)
- Elena Surova
- Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany; Department of Molecular immunology, Faculty of Biology, University of Freiburg and Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Hassan Jumaa
- Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany; Department of Molecular immunology, Faculty of Biology, University of Freiburg and Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Department of Immunology, Ulm University, Ulm, Germany.
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13
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Pang SHM, Carotta S, Nutt SL. Transcriptional control of pre-B cell development and leukemia prevention. Curr Top Microbiol Immunol 2014; 381:189-213. [PMID: 24831348 DOI: 10.1007/82_2014_377] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The differentiation of early B cell progenitors is controlled by multiple transcriptional regulators and growth-factor receptors. The triad of DNA-binding proteins, E2A, EBF1, and PAX5 is critical for both the early specification and commitment of B cell progenitors, while a larger number of secondary determinants, such as members of the Ikaros, ETS, Runx, and IRF families have more direct roles in promoting stage-specific pre-B gene-expression program. Importantly, it is now apparent that mutations in many of these transcription factors are associated with the progression to acute lymphoblastic leukemia. In this review, we focus on recent studies that have shed light on the transcriptional hierarchy that controls efficient B cell commitment and differentiation as well as focus on the oncogenic consequences of the loss of many of the same factors.
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Affiliation(s)
- Swee Heng Milon Pang
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
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Anbazhagan K, Rabbind Singh A, Isabelle P, Stella I, Céline ADM, Bissac E, Bertrand B, Rémy N, Naomi T, Vincent F, Rochette J, Lassoued K. Human pre-B cell receptor signal transduction: evidence for distinct roles of PI3kinase and MAP-kinase signalling pathways. IMMUNITY INFLAMMATION AND DISEASE 2013; 1:26-36. [PMID: 25400915 PMCID: PMC4217539 DOI: 10.1002/iid3.4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/08/2013] [Accepted: 07/11/2013] [Indexed: 12/16/2022]
Abstract
Pre-BCR acts as a critical checkpoint in B cell development. However, its signalling cascade still remains indistinctly characterised in human. We investigated pre-BCR signalling pathway to examine its regulation in normal primary pre-B lymphocytes and pre-B cell lines. In cell lines, early signalling events occurring after pre-BCR stimulation include phosphorylation of Lyn, Blk and Syk together with ZAP70, Btk, Vav, PLC-γ2 and various adaptor proteins, such as BLNK, LAB, LAT and SLP-76. Further downstream, these molecules induced activation of the PI3K/AKT and MAP-kinase resulting in an augmentation of canonical NF-κB pathways and cFos/AP1 activation. PI3K and MAPK exerted opposing effects on the pre-BCR-induced activation of the canonical NF-κB and c-Fos/AP1 pathways. Immediate nuclear export of FoxO3A and delayed import of IRF4 were additional events observed after pre-BCR crosslinking in primary cells. Pre-BCR-induced down-regulation of Rag1, Rag2, E2A and Pax5 transcripts occurred in a PI3K-dependent manner. Finally we bring evidence that pre-BCR stimulation or co stimulation with CD19 enhances cell cycle signal.
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Affiliation(s)
- Kolandaswamy Anbazhagan
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Amrathlal Rabbind Singh
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Piec Isabelle
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Ibata Stella
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Alleaume-De Martel Céline
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Eliane Bissac
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Brassart Bertrand
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Nyga Rémy
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Taylor Naomi
- CNRS/UMR 5535, Institut de Génétique Moléculaire de Montpellier 1919 Route de Mende, 34293, Montpellier, Cedex 5, France
| | - Fuentes Vincent
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Jacques Rochette
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
| | - Kaïss Lassoued
- Inserm/UMR925, Université Picardie Jules Verne, Laboratoire d'Immunologie, UFR de Médecine 3, rue des Louvels, 80036, Amiens, France
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15
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Huang L, Lange MD, Yu Y, Li S, Su K, Zhang Z. Contribution of V(H) replacement products in mouse antibody repertoire. PLoS One 2013; 8:e57877. [PMID: 23469094 PMCID: PMC3585286 DOI: 10.1371/journal.pone.0057877] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 01/30/2013] [Indexed: 11/19/2022] Open
Abstract
VH replacement occurs through RAG-mediated recombination between the cryptic recombination signal sequence (cRSS) near the 3′ end of a rearranged VH gene and the 23-bp RSS from an upstream unrearranged VH gene. Due to the location of the cRSS, VH replacement leaves a short stretch of nucleotides from the previously rearranged VH gene at the newly formed V-D junction, which can be used as a marker to identify VH replacement products. To determine the contribution of VH replacement products to mouse antibody repertoire, we developed a Java-based VH Replacement Footprint Analyzer (VHRFA) program and analyzed 17,179 mouse IgH gene sequences from the NCBI database to identify VH replacement products. The overall frequency of VH replacement products in these IgH genes is 5.29% based on the identification of pentameric VH replacement footprints at their V-D junctions. The identified VH replacement products are distributed similarly in IgH genes using most families of VH genes, although different families of VH genes are used differentially. The frequencies of VH replacement products are significantly elevated in IgH genes derived from several strains of autoimmune prone mice and in IgH genes encoding autoantibodies. Moreover, the identified VH replacement footprints in IgH genes from autoimmune prone mice or IgH genes encoding autoantibodies preferentially encode positively charged amino acids. These results revealed a significant contribution of VH replacement products to the diversification of antibody repertoire and potentially, to the generation of autoantibodies in mice.
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Affiliation(s)
- Lin Huang
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Miles D. Lange
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Yangsheng Yu
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Song Li
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kaihong Su
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- The Eppley Cancer Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Zhixin Zhang
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- The Eppley Cancer Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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16
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A novel mechanism for the autonomous termination of pre-B cell receptor expression via induction of lysosome-associated protein transmembrane 5. Mol Cell Biol 2012; 32:4462-71. [PMID: 22949502 DOI: 10.1128/mcb.00531-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The expression of the pre-B cell receptor (BCR) is confined to the early stage of B cell development, and its dysregulation is associated with anomalies of B-lineage cells, including leukemogenesis. Previous studies suggested that the pre-BCR signal might trigger the autonomous termination of pre-BCR expression even before the silencing of pre-BCR gene expression to prevent sustained pre-BCR expression. However, the underlying mechanism remains ill defined. Here we demonstrate that the pre-BCR signal induces the expression of lysosome-associated protein transmembrane 5 (LAPTM5), which leads to the prompt downmodulation of the pre-BCR. While LAPTM5 induction had no significant impact on the internalization of cell surface pre-BCR, it elicited the translocation of a large pool of intracellular pre-BCR from the endoplasmic reticulum to the lysosomal compartment concomitantly with a drastic reduction of the level of intracellular pre-BCR proteins. This reduction was inhibited by lysosomal inhibitors, indicating the lysosomal degradation of the pre-BCR. Notably, the LAPTM5 deficiency in pre-B cells led to the augmented expression level of surface pre-BCR. Collectively, the pre-BCR induces the prompt downmodulation of its own expression through the induction of LAPTM5, which promotes the lysosomal transport and degradation of the intracellular pre-BCR pool and, hence, limits the supply of pre-BCR to the cell surface.
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17
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Shahaf G, Gross AJ, Sternberg-Simon M, Kaplan D, DeFranco AL, Mehr R. Lyn deficiency affects B-cell maturation as well as survival. Eur J Immunol 2011; 42:511-21. [PMID: 22057631 DOI: 10.1002/eji.201141940] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 10/21/2011] [Accepted: 10/24/2011] [Indexed: 01/02/2023]
Abstract
Lyn, an Src-family protein tyrosine kinase expressed in B lymphocytes, contributes to initiation of BCR signaling and is also responsible for feedback inhibition of BCR signaling. Lyn-deficient mice have a decreased number of follicular B cells and also spontaneously develop a lupus-like autoimmunity. We used flow cytometric analysis, BrdU labeling and our mathematical models of B-cell population dynamics, to analyze how Lyn deficiency impacts B-cell maturation and survival. We found that Lyn-deficient transitional 1 (T1) cells develop normally, but T2 cells develop primarily from the T1 subset in the spleen and fail to also develop directly from BM immature B cells. Lyn-deficient T2 cells either mature to the follicular B-cell type at a close to normal rate, or die in this compartment rather than access the T3 anergic subset. The ≈ 40% of WT follicular cells that were short-lived exited primarily by joining the T3 anergic subset, whereas the ≈ 15% Lyn(-/-) follicular cells that were not long lived had a high death rate and died in this compartment rather than entering the T3 subset. We hypothesize that exaggerated BCR signaling resulting from weak interactions with self-antigens is largely responsible for these alterations in Lyn-deficient B cells.
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Affiliation(s)
- Gitit Shahaf
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
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18
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The P4-type ATPase ATP11C is essential for B lymphopoiesis in adult bone marrow. Nat Immunol 2011; 12:434-40. [PMID: 21423172 PMCID: PMC3079768 DOI: 10.1038/ni.2012] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 02/23/2011] [Indexed: 02/06/2023]
Abstract
B lymphopoiesis begins in fetal liver, switching to bone marrow after birth where it persists for life. The unique developmental outcomes of each phase are well documented, yet their molecular requirements are not. Here we describe two allelic X-linked mutations in mice that caused a cell-intrinsic arrest of adult B lymphopoiesis. Mutant fetal liver progenitors generated B cells in situ, but not in irradiated adult bone marrow, highlighting a necessity for the affected pathway only in the context of adult bone marrow. The causative mutation was ascribed to Atp11c, which encodes a P4-type ATPase with no previously described function. Our data establish an essential, cell-autonomous and context-sensitive function for ATP11C, a putative aminophospholipid flippase, in B cell development.
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19
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Nahar R, Müschen M. Pre-B cell receptor signaling in acute lymphoblastic leukemia. Cell Cycle 2009; 8:3874-7. [PMID: 19901533 DOI: 10.4161/cc.8.23.10035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
B cell lineage ALL represents by far the most frequent malignancy in children and is also common in adults. Despite significant advances over the past four decades, cytotoxic treatment strategies have recently reached a plateau with cure rates at 80 percent for children and 55 percent for adults. Relapse after cytotoxic drug treatment, initial drug-resistance and dose-limiting toxicity are among the most frequent complications of current therapy approaches. For this reason, pathway-specific treatment strategies in addition to cytotoxic drug treatment seem promising to further improve therapy options for ALL patients. In a recent study on 111 cases of pre-B cell-derived human ALL, we found that ALL cells carrying a BCR-ABL1-gene rearrangement lack expression of a functional pre-B cell receptor in virtually all cases. In a proof-of-principle experiment, we studied pre-B cell receptor function during progressive leukemic transformation of pre-B cells in BCR-ABL1-transgenic mice: Interestingly, signaling from the pre-B cell receptor and the oncogenic BCR-ABL1 kinase are mutually exclusive and only "crippled" pre-B cells that fail to express a functional pre-B cell receptor are permissive to transformation by BCR-ABL1.
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Affiliation(s)
- Rahul Nahar
- Leukemia and Lymphoma Program, USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA
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20
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gp96, an endoplasmic reticulum master chaperone for integrins and Toll-like receptors, selectively regulates early T and B lymphopoiesis. Blood 2009; 115:2380-90. [PMID: 19965672 DOI: 10.1182/blood-2009-07-233031] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Integrins contribute to lymphopoiesis, whereas Toll-like receptors (TLRs) facilitate the myeloid replenishment during inflammation. The combined role of TLRs and integrin on hematopoiesis remains unclear. gp96 (grp94, HSP90b1) is an endoplasmic reticulum master chaperone for multiple TLRs. We report herein that gp96 is also essential for expression of 14 hematopoietic system-specific integrins. Genetic deletion of gp96 thus enables us to determine the collective roles of gp96, integrins, and TLRs in hematopoiesis. We found that gp96-null hematopoietic stem cells could support long-term myelopoiesis. B- and T-cell development, however, was severely compromised with transitional block from pro-B to pre-B cells and the inability of thymocytes to develop beyond the CD4(-)CD8(-) stage. These defects were cell-intrinsic and could be recapitulated on bone marrow stromal cell culture. Furthermore, defective lymphopoiesis correlated strongly with failure of hematopoietic progenitors to form close contact with stromal cell niche and was not the result of the defect in the assembly of antigen receptor or interleukin-7 signaling. These findings define gp96 as the only known molecular chaperone to specifically regulate T- and B-cell development.
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21
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Li M, Marin-Muller C, Bharadwaj U, Chow KH, Yao Q, Chen C. MicroRNAs: control and loss of control in human physiology and disease. World J Surg 2009; 33:667-84. [PMID: 19030926 PMCID: PMC2933043 DOI: 10.1007/s00268-008-9836-x] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Analysis of the human genome indicates that a large fraction of the genome sequences are RNAs that do not encode any proteins, also known as non-coding RNAs. MicroRNAs (miRNAs) are a group of small non-coding RNA molecules 20-22 nucleotides (nt) in length that are predicted to control the activity of approximately 30% of all protein-coding genes in mammals. miRNAs play important roles in many diseases, including cancer, cardiovascular disease, and immune disorders. The expression of miRNAs can be regulated by epigenetic modification, DNA copy number change, and genetic mutations. miRNAs can serve as a valuable therapeutic target for a large number of diseases. For miRNAs with oncogenic capabilities, potential therapies include miRNA silencing, antisense blocking, and miRNA modifications. For miRNAs with tumor suppression functions, overexpression of those miRNAs might be a useful strategy to inhibit tumor growth. In this review, we discuss the current progress of miRNA research, regulation of miRNA expression, prediction of miRNA targets, and regulatory role of miRNAs in human physiology and diseases, with a specific focus on miRNAs in pancreatic cancer, liver cancer, colorectal cancer, cardiovascular disease, the immune system, and infectious disease. This review provides valuable information for clinicians and researchers who want to recognize the newest advances in this new field and identify possible lines of investigation in miRNAs as important mediators in human physiology and diseases.
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Affiliation(s)
- Min Li
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
| | - Christian Marin-Muller
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
| | - Uddalak Bharadwaj
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
| | - Kwong-Hon Chow
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
| | - Qizhi Yao
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
| | - Changyi Chen
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery and Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, Texas, USA
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22
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Alter-Wolf S, Blomberg BB, Riley RL. Deviation of the B cell pathway in senescent mice is associated with reduced surrogate light chain expression and altered immature B cell generation, phenotype, and light chain expression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:138-47. [PMID: 19109144 PMCID: PMC2749601 DOI: 10.4049/jimmunol.182.1.138] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
B lymphopoiesis in aged mice is characterized by reduced B cell precursors and an altered Ab repertoire. This likely results, in part, from reduced surrogate L chains in senescent B cell precursors and compromised pre-BCR checkpoints. Herein, we show that aged mice maintain an ordinarily minor pool of early c-kit(+) pre-B cells, indicative of poor pre-BCR expression, even as pre-BCR competent early pre-B cells are significantly reduced. Therefore, in aged mice, B2 B lymphopoiesis shifts from dependency on pre-BCR expansion and selection to more pre-BCR-deficient pathways. B2 c-kit(+) B cell precursors, from either young or aged mice, generate new B cells in vitro that are biased to larger size, higher levels of CD43, and decreased kappa L chain expression. Notably, immature B cells in aged bone marrow exhibit a similar phenotype in vivo. We hypothesize that reduced surrogate L chain expression contributes to decreased pre-B cells in aged mice. The B2 pathway is partially blocked with limited B cell development and reduced pre-BCR expression and signaling. In old age, B2 pathways have limited surrogate L chain and increasingly generate new B cells with altered phenotype and L chain expression.
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MESH Headings
- Aging/genetics
- Aging/immunology
- Animals
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- B-Lymphocyte Subsets/pathology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/metabolism
- Bone Marrow Cells/pathology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Lineage/genetics
- Cell Lineage/immunology
- Cells, Cultured
- Immunoglobulin Light Chains, Surrogate/biosynthesis
- Immunoglobulin Light Chains, Surrogate/genetics
- Immunoglobulin Light Chains, Surrogate/metabolism
- Immunophenotyping
- Lymphopenia/genetics
- Lymphopenia/immunology
- Lymphopenia/pathology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Pre-B Cell Receptors/deficiency
- Pre-B Cell Receptors/metabolism
- Pre-B Cell Receptors/physiology
- Precursor Cells, B-Lymphoid/immunology
- Precursor Cells, B-Lymphoid/metabolism
- Precursor Cells, B-Lymphoid/pathology
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Sarah Alter-Wolf
- Department of Microbiology and Immunology University of Miami Miller School of Medicine Miami, FL 33101
| | - Bonnie B. Blomberg
- Department of Microbiology and Immunology University of Miami Miller School of Medicine Miami, FL 33101
| | - Richard L. Riley
- Department of Microbiology and Immunology University of Miami Miller School of Medicine Miami, FL 33101
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23
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Martin DA, Lu L, Cascalho M, Wu GE. Maintenance of Surrogate Light Chain Expression Induces Developmental Delay in Early B Cell Compartment. THE JOURNAL OF IMMUNOLOGY 2007; 179:4996-5005. [PMID: 17911584 DOI: 10.4049/jimmunol.179.8.4996] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The production of a mature B cell requires passage through a number of developmental checkpoints. The pre-BCR plays a critical role in passage through the pro-B cell/pre-B cell checkpoint, and thus plays a central role in regulating the differentiation of a B cell. Due to the significance of this receptor, it is imperative that pre-BCR expression and function are precisely regulated. In this study, we have investigated a system in which the regulation of the pre-BCR is altered. We have found that continued expression of components of the pre-BCR (lambda5) resulted in a delay in the kinetics of B cell maturation. Pro-B cells from normal mouse bone marrow retrovirally infected with lambda5 exhibited a delay in differentiation. As compared with wild-type cells at the same time point, there is a reduction in the presence of cell surface markers that indicate developmental progression, and there is a 6- to 16-fold decrease in the production of Ig-positive cells in B cell maturation assays. The capacity to alter B cell progression by modifying and extending pre-BCR expression argues that the receptor and its associated signals play a unique role in directing developmental outcomes.
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Affiliation(s)
- Denise A Martin
- Department of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
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24
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Bankovich AJ, Raunser S, Juo ZS, Walz T, Davis MM, Garcia KC. Structural insight into pre-B cell receptor function. Science 2007; 316:291-4. [PMID: 17431183 DOI: 10.1126/science.1139412] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The pre-B cell receptor (pre-BCR) serves as a checkpoint in B cell development. In the 2.7 angstrom structure of a human pre-BCR Fab-like fragment, consisting of an antibody heavy chain (HC) paired with the surrogate light chain, the "unique regions" of VpreB and lambda5 replace the complementarity-determining region 3 (CDR3) loop of an antibody light chain and appear to "probe" the HC CDR3, potentially influencing the selection of the antibody repertoire. Biochemical analysis indicates that the pre-BCR is impaired in its ability to recognize antigen, which, together with electron microscopic visualization of a pre-BCR dimer, suggests ligand-independent oligomerization as the likely signaling mechanism.
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Affiliation(s)
- Alexander J Bankovich
- Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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25
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Zhou B, Wang S, Mayr C, Bartel DP, Lodish HF. miR-150, a microRNA expressed in mature B and T cells, blocks early B cell development when expressed prematurely. Proc Natl Acad Sci U S A 2007; 104:7080-5. [PMID: 17438277 PMCID: PMC1855395 DOI: 10.1073/pnas.0702409104] [Citation(s) in RCA: 490] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) are a family of approximately 22-nt noncoding RNAs that can posttranscriptionally regulate gene expression. Several miRNAs are specifically expressed in hematopoietic cells. Here we show that one such miRNA, miR-150, is mainly expressed in the lymph nodes and spleen and is highly up-regulated during the development of mature T and B cells; expression of miR-150 is sharply up-regulated at the immature B cell stage. Overexpression of miR-150 in hematopoietic stem cells, followed by bone marrow transplantation, had little effect on the formation of either mature CD8- and CD4-positive T cells or granulocytes or macrophages, but the formation of mature B cells was greatly impaired. Furthermore, premature expression of miR-150 blocked the transition from the pro-B to the pre-B stage. Our results indicate that miR-150 most likely down-regulates mRNAs that are important for pre- and pro-B cell formation or function, and its ectopic expression in these cells blocks further development of B cells.
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Affiliation(s)
- Beiyan Zhou
- *Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142; and
| | | | - Christine Mayr
- *Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142; and
- Department of Biology and
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - David P. Bartel
- *Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142; and
- Department of Biology and
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Harvey F. Lodish
- *Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142; and
- Department of Biology and
- To whom correspondence should be addressed. E-mail:
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26
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Meixlsperger S, Köhler F, Wossning T, Reppel M, Müschen M, Jumaa H. Conventional Light Chains Inhibit the Autonomous Signaling Capacity of the B Cell Receptor. Immunity 2007; 26:323-33. [PMID: 17331747 DOI: 10.1016/j.immuni.2007.01.012] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 12/14/2006] [Accepted: 01/26/2007] [Indexed: 02/06/2023]
Abstract
Signals from the B cell antigen receptor (BCR), consisting of mu heavy chain (muHC) and conventional light chain (LC), and its precursor the pre-BCR, consisting of muHC and surrogate light chain (SLC), via the adaptor protein SLP-65 regulate the development and function of B cells. Here, we compare the effect of SLC and conventional LC expression on receptor-induced Ca(2+) flux in B cells expressing an inducible form of SLP-65. We found that SLC expression strongly enhanced an autonomous ability of muHC to induce Ca(2+) flux irrespective of additional receptor crosslinking. In contrast, LC expression reduced this autonomous muHC ability and resulted in antigen-dependent Ca(2+) flux. These data indicate that autonomous ligand-independent signaling can be induced by receptor forms other than the pre-BCR. In addition, our data suggest that conventional LCs play an important role in the inhibition of autonomous receptor signaling, thereby allowing further B cell differentiation.
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Affiliation(s)
- Sonja Meixlsperger
- Institute for Biology III, Albert-Ludwigs University of Freiburg and Max Planck Institute for Immunobiology, Stuebeweg 51, 79108 Freiburg, Germany
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27
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Ma S, Turetsky A, Trinh L, Lu R. IFN regulatory factor 4 and 8 promote Ig light chain kappa locus activation in pre-B cell development. THE JOURNAL OF IMMUNOLOGY 2007; 177:7898-904. [PMID: 17114461 DOI: 10.4049/jimmunol.177.11.7898] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previous studies have shown that B cell development is blocked at the pre-B cell stage in IFN regulatory factor (IRF)4 (pip) and IRF8 (IFN consensus sequence binding protein) double mutant mice (IRF4,8(-/-)). In this study, the molecular mechanism by which IRF4,8 regulate pre-B cell development was further investigated. We show that IRF4,8 function in a B cell intrinsic manner to control pre-B cell development. IRF4,8(-/-) mice expressing a Bcl-2 transgene fail to rescue pre-B cell development, suggesting that the defect in B cell development in IRF4,8(-/-) mice is not due to a lack of survival signal. IRF4,8(-/-) pre-B cells display a high proliferation index that may indirectly inhibit the L chain rearrangement. However, forced cell cycle exit induced by IL-7 withdrawal fails to rescue the development of IRF4,8(-/-) pre-B cells, suggesting that cell cycle exit by itself is not sufficient to rescue the development of IRF4,8(-/-) pre-B cells and that IRF4,8 may directly regulate the activation of L chain loci. Using retroviral mediated gene transduction, we show that IRF4 and IRF8 function redundantly to promote pre-B cell maturation and the generation of IgM(+) B cells. Molecular analysis indicates that IRF4, when expressed in IRF4,8(-/-) pre-B cells, induces kappa germline transcription, enhances V(D)J rearrangement activity at the kappa locus, and promotes L chain rearrangement and transcription. Chromatin immunoprecipitation assay further reveals that IRF4 expression leads to histone modifications and enhanced chromatin accessibility at the kappa locus. Thus, IRF4,8 control pre-B cell development, at least in part, by promoting the activation of the kappa locus.
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Affiliation(s)
- Shibin Ma
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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28
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Song H, Zhang J, Chiang YJ, Siraganian RP, Hodes RJ. Redundancy in B Cell Developmental Pathways: c-Cbl Inactivation Rescues Early B Cell Development through a B Cell Linker Protein-Independent Pathway. THE JOURNAL OF IMMUNOLOGY 2007; 178:926-35. [PMID: 17202354 DOI: 10.4049/jimmunol.178.2.926] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Deficiency in the adaptor protein B cell linker protein (BLNK) results in a substantial but incomplete block in B cell development, suggesting that alternative pathways exist for B lineage differentiation. Another adaptor protein, c-Cbl, plays a negative regulatory role in several BCR-signaling pathways. We therefore investigated the role of c-Cbl during B cell development and addressed the possibility that redundancies in pathways for B cell differentiation could be further revealed by eliminating negative effects mediated by c-Cbl. Strikingly, c-Cbl inactivation reversed a number of the critical defects in early B cell differentiation that are seen in BLNK-deficient mice. c-Cbl(-/-)BLNK(-/-) mice exhibited normalized down-regulation of pre-BCR and CD43, up-regulation of MHC class II, and augmented L chain rearrangement, resulting in a successful transition from pre-B cells to immature B cells. c-Cbl inactivation also reversed the potentially tumor-predisposing hyperproliferative response of BLNK(-/-) pre-B cells to IL-7. Pre-BCR cross-linking induced enhanced and prolonged tyrosine phosphorylation in c-Cbl(-/-)BLNK(-/-) pre-BCR(+) pre-B cells compared with c-Cbl(+/-)BLNK(-/-) cells, including elevated phosphorylation of Lyn, Syk, Btk, and phospholipase C-gamma2. Our studies suggest that some, but not all, pre-BCR-triggered developmental events can be mediated by BLNK-independent pathways that are negatively regulated by c-Cbl, and further suggest that different events during early B cell development require different strength or duration of pre-BCR signaling.
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Affiliation(s)
- Haifeng Song
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
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29
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Abstract
The prevalence of immunoglobulin E (IgE)-mediated allergic diseases has been increasing for the last four decades. In this review determinants for an increased IgE synthesis are discussed on both an epidemiological and on an immunological level with special emphasis on the differentiation of the B cell to an IgE-producing plasma cell. Factors that favor an IgE immune response are low antigen doses and immunization via mucous membranes, but it is highly likely that other environmental factors besides exposure to the allergenic sources play a role. Important factors in the formation of the Thelper type 2 (Th2) T cell subset are the actions of thymic stromal lymphopoietin (TSLP) on dendritic cells and the OX40 ligand on CD4+ T cells. In order for a B lymphocyte to switch to IgE production it needs two signals provided by a Th2 cell in the form of the cytokines interleukin (IL-) 4/IL-13 and ligation of the CD40. In spite of a half-life of only a few days, there is evidence that the IgE response may last for years even without allergen stimulation. This is likely to be caused by long-lived IgE-producing plasma cells, and such cells may be difficult to target therapeutically thus emphasizing the need for more knowledge on preventable causes of IgE- and allergy development.
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Affiliation(s)
- Lars K Poulsen
- Laboratory of Medical Allergology, Allergy Clinic, National University Hospital, Copenhagen, Denmark.
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30
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Wossning T, Herzog S, Köhler F, Meixlsperger S, Kulathu Y, Mittler G, Abe A, Fuchs U, Borkhardt A, Jumaa H. Deregulated Syk inhibits differentiation and induces growth factor-independent proliferation of pre-B cells. ACTA ACUST UNITED AC 2006; 203:2829-40. [PMID: 17130299 PMCID: PMC2118175 DOI: 10.1084/jem.20060967] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The nonreceptor protein spleen tyrosine kinase (Syk) is a key mediator of signal transduction in a variety of cell types, including B lymphocytes. We show that deregulated Syk activity allows growth factor–independent proliferation and transforms bone marrow–derived pre–B cells that are then able to induce leukemia in mice. Syk-transformed pre–B cells show a characteristic pattern of tyrosine phosphorylation, increased c-Myc expression, and defective differentiation. Treatment of Syk-transformed pre–B cells with a novel Syk-specific inhibitor (R406) reduces tyrosine phosphorylation and c-Myc expression. In addition, R406 treatment removes the developmental block and allows the differentiation of the Syk-transformed pre–B cells into immature B cells. Because R406 treatment also prevents the proliferation of c-Myc–transformed pre–B cells, our data indicate that endogenous Syk kinase activity may be required for the survival of pre–B cells transformed by other oncogenes. Collectively, our data suggest that Syk is a protooncogene involved in the transformation of lymphocytes, thus making Syk a potential target for the treatment of leukemia.
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Affiliation(s)
- Thomas Wossning
- Institute of Biology III, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, and Department of Pediatric Hematology and Oncology, Children's Hospital, Munich, Germany
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31
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Abstract
The specificities of lymphocytes for antigen are generated by a quasi-random process of gene rearrangement that often results in non-functional or autoreactive antigen receptors. Regulation of lymphocyte specificities involves not only the elimination of cells that display 'unsuitable' receptors for antigen but also the active genetic correction of these receptors by secondary recombination of the DNA. As I discuss here, an important mechanism for the genetic correction of antigen receptors is ongoing recombination, which leads to receptor editing. Receptor editing is probably an adaptation that is necessitated by the high probability of receptor autoreactivity. In both B cells and T cells, the genes that encode the two chains of the antigen receptor seem to be specialized to promote, on the one hand, the generation of diverse specificities and, on the other hand, the regulation of these specificities through efficient editing.
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Affiliation(s)
- David Nemazee
- Department of Immunology, The Scripps Research Institute, Mail Drop IMM-29, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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32
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Kawano Y, Yoshikawa S, Minegishi Y, Karasuyama H. Pre-B cell receptor assesses the quality of IgH chains and tunes the pre-B cell repertoire by delivering differential signals. THE JOURNAL OF IMMUNOLOGY 2006; 177:2242-9. [PMID: 16887984 DOI: 10.4049/jimmunol.177.4.2242] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well understood how a variety of Ig H and L chains, components of BCR, are generated in the DNA level during B cell development. However, it has remained largely unknown whether and how each component is monitored for its quality and selected before the assembly into the BCR. Here we show that muH chains produced by pre-B cells display a wide spectrum of ability to form the pre-BCR, which is composed of muH and surrogate light (SL) chains and is crucial for B cell development. The level of surface pre-BCR expression varies among pre-B cells, depending on the ability of their muH chains to pair with SL chains. The higher the level of pre-BCR expression by pre-B cells, the stronger their pre-BCR signaling, and the better they proliferate and differentiate. Thus, the extent of survival, proliferation, and differentiation of individual pre-B cells is primarily determined by the SL-pairing ability of their muH chains. Furthermore, IgH chains with higher potential to assemble with IgL chains appear to be positively selected and amplified through the assessment of their ability to pair with SL chains at the pre-BCR checkpoint before the assembly into the BCR. These results indicate that the pre-BCR assesses the quality of muH chains and tunes the pre-B cell repertoire by driving the preferential expansion and differentiation of cells with the higher quality of muH chains.
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Affiliation(s)
- Yohei Kawano
- Department of Immune Regulation, Tokyo Medical and Dental University Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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33
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Kersseboom R, Ta VBT, Zijlstra AJE, Middendorp S, Jumaa H, van Loo PF, Hendriks RW. Bruton's tyrosine kinase and SLP-65 regulate pre-B cell differentiation and the induction of Ig light chain gene rearrangement. THE JOURNAL OF IMMUNOLOGY 2006; 176:4543-52. [PMID: 16585544 DOI: 10.4049/jimmunol.176.8.4543] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bruton's tyrosine kinase (Btk) and the adapter protein SLP-65 (Src homology 2 domain-containing leukocyte-specific phosphoprotein of 65 kDa) transmit precursor BCR (pre-BCR) signals that are essential for efficient developmental progression of large cycling into small resting pre-B cells. We show that Btk- and SLP-65-deficient pre-B cells have a specific defect in Ig lambda L chain germline transcription. In Btk/SLP-65 double-deficient pre-B cells, both kappa and lambda germline transcripts are severely reduced. Although these observations point to an important role for Btk and SLP-65 in the initiation of L chain gene rearrangement, the possibility remained that these signaling molecules are only required for termination of pre-B cell proliferation or for pre-B cell survival, whereby differentiation and L chain rearrangement is subsequently initiated in a Btk/SLP-65-independent fashion. Because transgenic expression of the antiapoptotic protein Bcl-2 did not rescue the developmental arrest of Btk/SLP-65 double-deficient pre-B cells, we conclude that defective L chain opening in Btk/SLP-65-deficient small resting pre-B cells is not due to their reduced survival. Next, we analyzed transgenic mice expressing the constitutively active Btk mutant E41K. The expression of E41K-Btk in Ig H chain-negative pro-B cells induced 1) surface marker changes that signify cellular differentiation, including down-regulation of surrogate L chain and up-regulation of CD2, CD25, and MHC class II; and 2) premature rearrangement and expression of kappa and lambda light chains. These findings demonstrate that Btk and SLP-65 transmit signals that induce cellular maturation and Ig L chain rearrangement independently of their role in termination of pre-B cell expansion.
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Affiliation(s)
- Rogier Kersseboom
- Department of Immunology, Erasmus Medical Center, Rotterdam, The Netherlands
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34
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Zhang Z, Espinoza CR, Yu Z, Stephan R, He T, Williams GS, Burrows PD, Hagman J, Feeney AJ, Cooper MD. Transcription factor Pax5 (BSAP) transactivates the RAG-mediated V(H)-to-DJ(H) rearrangement of immunoglobulin genes. Nat Immunol 2006; 7:616-24. [PMID: 16680144 DOI: 10.1038/ni1339] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 03/27/2006] [Indexed: 11/09/2022]
Abstract
Immunoglobulin rearrangement from variable heavy chain (V(H)) to diversity (D)-joining heavy chain (J(H)), which occurs exclusively in B lineage cells, is impaired in mice deficient for the B lineage-specific transcription factor Pax5. Conversely, ectopic Pax5 expression in thymocytes promotes the rearrangement of D(H)-proximal V(H)7183 genes. In exploring the mechanism for Pax5 regulation of V(H)-to-DJ(H) recombination, we have identified multiple Pax5 binding sites in the coding regions of human and mouse V(H) gene segments. Pax5 bound to those sites in vitro and occupied V(H) genes in early human and mouse B lineage cells. Moreover, Pax5 interacted with the recombination-activating gene 1 (RAG1)-RAG2 complex to enhance RAG-mediated V(H) recombination signal sequence cleavage and recombination of a V(H) gene substrate. These findings indicate a direct activating function for Pax5 in RAG-mediated immunoglobulin V(H)-to-DJ(H) recombination.
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Affiliation(s)
- Zhixin Zhang
- Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, 35294, USA.
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35
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Vettermann C, Herrmann K, Jäck HM. Powered by pairing: The surrogate light chain amplifies immunoglobulin heavy chain signaling and pre-selects the antibody repertoire. Semin Immunol 2006; 18:44-55. [PMID: 16464608 DOI: 10.1016/j.smim.2006.01.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Selective expansion of functional pre-B cells is accomplished by the assembly of a signaling-competent pre-B cell receptor (pre-BCR) consisting of immunoglobulin mu heavy chains (muHC), surrogate light chains (SLC) and Igalpha/Igbeta. Here, we review recent data showing that muHCs, in the absence of SLC, deliver autonomous differentiation signals. However, enhanced signaling necessary for pre-B cell expansion requires cross-linking of pre-BCRs via the non-immunoglobulin tail of SLC's subunit lambda5. We also discuss how SLC's ability to modulate the strength of pre-BCR signals is controlled by a muHC's idiotype and its affinity to the chaperone BiP. In this model, BiP in concert with SLC functions as a pre-selector of the antibody repertoire.
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Affiliation(s)
- Christian Vettermann
- Division of Molecular Immunology, Department of Internal Medicine III, Nikolaus-Fiebiger-Center for Molecular Medicine, Friedrich-Alexander-University Erlangen-Nürnberg, D-91054 Erlangen, Germany
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36
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Abstract
Progenitor B lymphocytes that successfully assemble a heavy chain gene encoding an immunoglobulin capable of pairing with surrogate light chain proteins trigger their own further differentiation by signaling via the pre-BCR complex. The pre-BCR signals several rounds of proliferation and, in this expanded population, directs a complex, B cell-specific set of epigenetic changes resulting in allelic exclusion of the heavy chain locus and activation of the light chain loci for V(D)J recombination.
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Affiliation(s)
- Jamie K Geier
- UC-Berkeley, Department of Molecular & Cell Biology, Division of Immunology, 439 Life Sciences Addition, Berkeley, CA 94720-3200, USA
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37
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Mundt C, Licence S, Maxwell G, Melchers F, Mårtensson IL. Only VpreB1, but not VpreB2, is expressed at levels which allow normal development of B cells. Int Immunol 2005; 18:163-72. [PMID: 16361315 DOI: 10.1093/intimm/dxh359] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The surrogate light chain (SLC) consists of the polypeptides lambda5 and, in the mouse, either VpreB1 or VpreB2. SLC associates with BILL-Cadherin and other glycoproteins to form the pro-B cell receptor (pro-BCR) at the pre-BI cell stage, and with the immunoglobulin mu heavy chain to form the pre-BCR at the pre-BII cell stage. The function of the pro-BCR, if any, is unknown, whereas the pre-BCR is crucial for proliferative expansion of pre-BII cells. To shed light on the functional properties of VpreB1 and VpreB2 in vivo, mice with either one or two VpreB1, or one or two VpreB2, alleles have been investigated. We show that B cell development in mice with two VpreB1 alleles is indistinguishable from that of normal mice. In contrast, mice with two VpreB2 alleles show an approximately 1.6-fold increase in pre-BI and a 35% decrease in pre-BII cell numbers, while mice with only one VpreB2 allele show a reduction in B cell development manifested in a 2-fold enrichment in pre-BI cells and a 75% reduction in pre-BII cells. However, such a gene dosage effect is not observed for VpreB1. Our results suggest that the difference between VpreB1- and VpreB2-deficient mice is due to lower VpreB2 protein expression, thus limiting the formation of pre-BCRs and thereby the number of large, cycling pre-BII cells.
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Affiliation(s)
- Cornelia Mundt
- Laboratory of Lymphocyte Signaling and Development, Babraham Institute, Babraham Research Campus, Cambridge CB2 4AT, UK
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38
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Parker MJ, Licence S, Erlandsson L, Galler GR, Chakalova L, Osborne CS, Morgan G, Fraser P, Jumaa H, Winkler TH, Skok J, Mårtensson IL. The pre-B-cell receptor induces silencing of VpreB and lambda5 transcription. EMBO J 2005; 24:3895-905. [PMID: 16281060 PMCID: PMC1283949 DOI: 10.1038/sj.emboj.7600850] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 10/06/2005] [Indexed: 01/17/2023] Open
Abstract
The pre-B-cell receptor (pre-BCR), composed of Ig heavy and surrogate light chain (SLC), signals pre-BII-cell proliferative expansion. We have investigated whether the pre-BCR also signals downregulation of the SLC genes (VpreB and lambda5), thereby limiting this expansion. We demonstrate that, as BM cells progress from the pre-BI to large pre-BII-cell stage, there is a shift from bi- to mono-allelic lambda5 transcription, while the second allele is silenced in small pre-BII cells. A VpreB1-promoter-driven transgene shows the same pattern, therefore suggesting that VpreB1 is similarly regulated and thereby defines the promoter as a target for transcriptional silencing. Analyses of pre-BCR-deficient mice show a temporal delay in lambda5 downregulation, thereby demonstrating that the pre-BCR is essential for monoallelic silencing at the large pre-BII-cell stage. Our data also suggest that SLP-65 is one of the signaling components important for this process. Furthermore, the VpreB1/lambda5 alleles undergo dynamic changes with respect to nuclear positioning and heterochromatin association, thereby providing a possible mechanism for their transcriptional silencing.
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Affiliation(s)
- Mathew J Parker
- Laboratory of Lymphocyte Signaling and Development, The Babraham Institute, Cambridge, UK
| | - Steve Licence
- Laboratory of Lymphocyte Signaling and Development, The Babraham Institute, Cambridge, UK
| | - Lena Erlandsson
- Laboratory of Lymphocyte Signaling and Development, The Babraham Institute, Cambridge, UK
| | | | - Lyubomira Chakalova
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Cambridge, UK
| | - Cameron S Osborne
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Cambridge, UK
| | - Geoff Morgan
- Flow Cytometry Facility, The Babraham Institute, Cambridge, UK
| | - Peter Fraser
- Laboratory of Chromatin and Gene Expression, The Babraham Institute, Cambridge, UK
| | - Hassan Jumaa
- Institute for Biology III, Max-Planck-Institute for Immunobiology, Freiburg, Germany
| | | | - Jane Skok
- Department of Immunology and Molecular Pathology, UCL, London, UK
| | - Inga-Lill Mårtensson
- Laboratory of Lymphocyte Signaling and Development, The Babraham Institute, Cambridge, UK
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39
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Miyamoto T, Akashi K. Lineage promiscuous expression of transcription factors in normal hematopoiesis. Int J Hematol 2005; 81:361-7. [PMID: 16158815 DOI: 10.1532/ijh97.05003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hematopoiesis has provided a valuable model for examining how genetic programs are established and executed in terms of cell fate decision. Identification of common myeloid and lymphoid progenitors allows us to directly assess the regulatory mechanisms of lineage commitment. Multiple markers of hematopoietic lineages are coexpressed in hematopoietic stem cells and progenitors, a phenomenon referred to as lineage priming. Promiscuous expression of several lineage-affiliated genes precedes lineage commitment but does not alter the biological potential of hematopoietic stem cells and multipotent progenitors. Promiscuous accessibility of multiple programs allows flexibility in cell fate commitment at the multipotent stages, indicating that transcriptional promiscuity can operate in stem cells and progenitors to control their transition from multipotency to single-lineage commitment.
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Affiliation(s)
- Toshihiro Miyamoto
- Center for Cellular and Molecular Medicine, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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40
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Melchers F. The pre-B-cell receptor: selector of fitting immunoglobulin heavy chains for the B-cell repertoire. Nat Rev Immunol 2005; 5:578-84. [PMID: 15999097 DOI: 10.1038/nri1649] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In this Opinion article, I address the role of the pre-B-cell receptor (pre-BCR) in the development of antigen-specific B cells in terms of immunoglobulin heavy chain (IgH) variable-region repertoire selection, precursor B-cell differentiation and proliferation, and IgH allelic exclusion. Comparisons with the role of the pre-T-cell receptor (pre-TCR) in T-cell development raise provocative questions. Why do B- and T-cell lineages both use a surrogate chain - the surrogate light chain and the pre-TCR alpha-chain, respectively - as a step to develop their repertoires of antigen-recognizing cells? What are the functions of the pre-BCR and pre-TCR in lymphocyte differentiation and antigen-receptor allelic exclusion? This article, together with the accompanying article by Harald von Boehmer, hopes to answer some of these questions.
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Affiliation(s)
- Fritz Melchers
- Max Planck Institute for Infection Biology, Campus Charité Mitte, Schumannstrasse 21-22, D-10117 Berlin, Germany.
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41
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Kawano Y, Yoshikawa S, Minegishi Y, Karasuyama H. Selection of stereotyped VH81X-{micro}H chains via pre-B cell receptor early in ontogeny and their conservation in adults by marginal zone B cells. Int Immunol 2005; 17:857-67. [PMID: 15908445 DOI: 10.1093/intimm/dxh265] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The pre-B cell receptor (preBCR) plays critical roles in early B cell differentiation. It has been shown that not all muH chains are capable of pairing with surrogate light (SL) chains to form preBCR. Here, we established a novel system to differentially identify two types of early pre-B cell populations in bone marrow and fetal liver of mice, one producing SL-pairing muH chains and the other producing SL-non-pairing muH chains. The former population accounted for 80% of all the early pre-B cells in adult bone marrow, while it accounted for only 20% of those in fetal liver. Comparison of the two types of pre-B cell populations in fetal liver revealed the structural difference between SL-pairing and -non-pairing muH chains encoded by the V(H)81X segment that was most frequently utilized in fetal liver pre-B cells but rarely expressed by B cells generated in adults. PreBCR played an important role in the positive selection of V(H)81X-muH chains carrying the characteristic sequences of the complementarity-determining region 3 with little or no nibbling or N nucleotide addition, leading to their predominance in neonatal splenic B cells. These fetal-type V(H)81X-muH chains were also detected in adult spleen, but almost exclusively in marginal zone (MZ) B cells in contrast to the adult-type V(H)81X-muH chains. This strongly suggests that neonatally generated and selected B cells expressing the stereotyped V(H)81X-muH chains are maintained in the adult MZ and could function as innate-like lymphocytes.
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Affiliation(s)
- Yohei Kawano
- Department of Immune Regulation, Tokyo Medical and Dental University Graduate School, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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42
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Jimi E, Phillips RJ, Rincon M, Voll R, Karasuyama H, Flavell R, Ghosh S. Activation of NF-κB promotes the transition of large, CD43+ pre-B cells to small, CD43− pre-B cells. Int Immunol 2005; 17:815-25. [PMID: 15908447 DOI: 10.1093/intimm/dxh263] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The regulation of the transcription factor nuclear factor-kappaB (NF-kappaB) during B-cell development was examined using cells isolated from the bone marrow of transgenic mice expressing a kappaB luciferase reporter gene. The results indicate that the highest level of NF-kappaB activity is present in cells expressing the pre-B-cell receptor. Furthermore, cross-linking of Igbeta on CD43(+) pre-B cells is able to activate NF-kappaB in recombination-activating gene 1-deficient mice, preceding their further differentiation into CD43(-) pre-B cells. Expression of a dominant negative form of IkappaBalpha using a transgenic approach or by retroviral infection leads to a reduction in the number of CD43(+) pre-B cells. These data therefore indicate that activation of NF-kappaB in CD43(+) pre-B cells, as a result of signaling by the pre-B-cell receptor, facilitates the continued development of large, CD43(+) pre-B cells into small CD43(-) pre-B cells.
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Affiliation(s)
- Eijiro Jimi
- Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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43
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Sabbattini P, Dillon N. The λ5–VpreB1 locus—a model system for studying gene regulation during early B cell development. Semin Immunol 2005; 17:121-7. [PMID: 15737573 DOI: 10.1016/j.smim.2005.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The lambda5 and VpreB genes encode the components of the surrogate light-chain, which forms part of the pre-B cell receptor. In mouse, the lambda5 and VpreB1 genes of mouse are closely linked and coordinately regulated by a locus control region (LCR). Activation of the genes in pro-B cells depends on the combined effects of early B cell factor (EBF) and the E2A factors E12 and E47. Silencing of lambda5 expression in mature B cells occurs through the action of Ikaros on the gene promoter where it may compete for binding of EBF and initiate the formation of a silent chromatin structure.
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Affiliation(s)
- Pierangela Sabbattini
- Gene Regulation and Chromatin Group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Campus, Du Cane Road, London W12 ONN, UK.
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44
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Su YW, Herzog S, Lotz M, Feldhahn N, Müschen M, Jumaa H. The molecular requirements for LAT-mediated differentiation and the role of LAT in limiting pre-B cell expansion. Eur J Immunol 2005; 34:3614-22. [PMID: 15549729 DOI: 10.1002/eji.200425445] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Successful recombination of the heavy-chain locus in developing B cells results in the expression of the pre-BCR, which induces the proliferation and expansion of pre-B cells. To avoid uncontrolled proliferation, pre-BCR signals transmitted via the adaptor protein SLP-65 (SH2-domain-containing leukocyte protein of 65 kDa) lead to the down-regulation of pre-BCR expression and to pre-B cell differentiation. Here, we show that, similarly to SLP-65, the adaptor protein LAT (linker for activation of T cells) limits pre-B cell proliferation and reduces the potential of a tumorgenic pre-B cell line to develop leukemia in immune-deficient mice. We further show that the four distal tyrosines are required for LAT activity in pre-B cells. Mutation at Y136 completely abolishes LAT activity, whereas single point-mutations at Y175, Y195 or Y235 impair, but do not block, LAT-induced pre-B cell differentiation. As LAT is also expressed in human pre-B cells, our results suggest that LAT cooperates with SLP-65 to promote the differentiation and control the proliferation of both murine and human pre-B cells.
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Affiliation(s)
- Yu-Wen Su
- Institute for Biology III, Albert-Ludwigs University of Freiburg and Max Planck Institute for Immunobiology, Freiburg, Germany
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45
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Hayashi K, Nojima T, Goitsuka R, Kitamura D. Impaired receptor editing in the primary B cell repertoire of BASH-deficient mice. THE JOURNAL OF IMMUNOLOGY 2004; 173:5980-8. [PMID: 15528332 DOI: 10.4049/jimmunol.173.10.5980] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The editing of B cell Ag receptor (BCR) through successive rearrangements of Ig genes has been considered to be a major mechanism for the central B cell tolerance, which precludes appearance of self-reactive B cells, through studies using anti-self-Ig transgenic/knock-in mouse systems. However, contribution of the receptor editing in the development of the normal B cell repertoire remains unclear. In addition, the signaling pathway directing this event is unknown. In this study, we demonstrate that receptor editing in anti-DNA Ig knock-in mice is impaired in the absence of an adaptor protein BASH (BLNK/SLP-65) that is involved in BCR signaling. Remarkably, the supposed hallmarks of receptor editing such as Iglambda chain expression, recombination sequence rearrangements at Igkappa loci, and presence of in-frame VkappaJkappa joins in the Igkappa loci inactivated by the recombination sequence rearrangements, were all diminished in BASH-deficient mice with unmanipulated Ig loci. BCR ligation-induced Iglambda gene recombination in vitro was also impaired in BASH-deficient B cells. Furthermore, the BASH-deficient mice showed an excessive Ab response to a DNA carrier immunization, suggesting the presence of unedited DNA-reactive B cells in the periphery. These results not only define a signaling pathway required for receptor editing but indicate that the BCR-signaled receptor editing indeed operates in the development of normal B cell repertoire and contributes to establishing the B cell tolerance.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Antibodies, Antinuclear/biosynthesis
- Antibodies, Antinuclear/genetics
- Antibodies, Antinuclear/metabolism
- Autoantigens/immunology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/physiology
- Clonal Anergy/genetics
- Gene Rearrangement, B-Lymphocyte, Heavy Chain
- Genetic Markers/immunology
- Immunoglobulin Heavy Chains/biosynthesis
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/metabolism
- Immunoglobulin Variable Region/biosynthesis
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Phosphoproteins/deficiency
- Phosphoproteins/genetics
- Phosphoproteins/physiology
- RNA Editing/genetics
- RNA Editing/immunology
- Receptors, Antigen, B-Cell/genetics
- Signal Transduction/genetics
- Signal Transduction/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
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Affiliation(s)
- Katsuhiko Hayashi
- Division of Molecular Biology, Research Institute for Biological Sciences, Tokyo University of Science, Yamazaki 2669, Noda, Chiba 278-0022, Japan
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Middendorp S, Zijlstra AJE, Kersseboom R, Dingjan GM, Jumaa H, Hendriks RW. Tumor suppressor function of Bruton tyrosine kinase is independent of its catalytic activity. Blood 2004; 105:259-65. [PMID: 15331445 DOI: 10.1182/blood-2004-07-2708] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During B-cell development in the mouse, Bruton tyrosine kinase (Btk) and the adaptor protein SLP-65 (Src homology 2 [SH2] domain-containing leukocyte protein of 65 kDa) limit the expansion and promote the differentiation of pre-B cells. Btk is thought to mainly function by phosphorylating phospholipase Cgamma2, which is brought into close proximity of Btk by SLP-65. However, this model was recently challenged by the identification of a role for Btk as a tumor suppressor in the absence of SLP-65 and by the finding that Btk function is partially independent of its kinase activity. To investigate if enzymatic activity is critical for the tumor suppressor function of Btk, we crossed transgenic mice expressing the kinase-inactive K430R-Btk mutant onto a Btk/SLP-65 double-deficient background. We found that K430R-Btk expression rescued the severe developmental arrest at the pre-B-cell stage in Btk/SLP-65 double-deficient mice. Moreover, K430R-Btk could functionally replace wild-type Btk as a tumor suppressor in SLP-65- mice: at 6 months of age, the observed pre-B-cell lymphoma frequencies were approximately 15% for SLP-65- mice, 44% for Btk/SLP-65-deficient mice, and 14% for K430R-Btk transgenic mice on the Btk/SLP-65-deficient background. Therefore, we conclude that Btk exerts its tumor suppressor function in pre-B cells as an adaptor protein, independent of its catalytic activity.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Agammaglobulinaemia Tyrosine Kinase
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Calcium/metabolism
- Calcium Signaling
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Catalysis
- Cell Differentiation
- Cells, Cultured
- Immunoglobulin G/blood
- Immunoglobulin G/immunology
- Lymphoma, B-Cell/enzymology
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/metabolism
- Lymphoma, B-Cell/pathology
- Lysine/genetics
- Lysine/metabolism
- Mice
- Mice, Knockout
- Mice, Transgenic
- Phosphoproteins/deficiency
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Phosphotyrosine/metabolism
- Protein-Tyrosine Kinases/deficiency
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Receptors, Antigen, B-Cell/metabolism
- Survival Rate
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Affiliation(s)
- Sabine Middendorp
- Department of Immunology, Erasmus MC Rotterdam, Rotterdam, The Netherlands
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Ikeda A, Merchant M, Lev L, Longnecker R, Ikeda M. Latent membrane protein 2A, a viral B cell receptor homologue, induces CD5+ B-1 cell development. THE JOURNAL OF IMMUNOLOGY 2004; 172:5329-37. [PMID: 15100272 DOI: 10.4049/jimmunol.172.9.5329] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The latent membrane protein 2A (LMP2A) of EBV plays a key role in regulating viral latency and EBV pathogenesis by functionally mimicking a constitutively active B cell Ag receptor. When expressed as a B cell-specific transgene in mice, LMP2A drives B cell development, resulting in the bypass of normal developmental checkpoints. In this study, we have demonstrated that expression of LMP2A in transgenic mice results in B cell development that exclusively favors B-1 cells. This switch to B-1 cell development occurs at the pre-B-cell stage of normal B cell development in the bone marrow, a B cell stage much earlier than appreciated for B-1 commitment. This finding indicates that all pre-B cells have the capacity to assume a B-1 cell phenotype if they encounter the appropriate signal during normal development. Furthermore, these studies offer insight into EBV latency and pathogenesis in the human host.
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MESH Headings
- Animals
- Antigens, CD/biosynthesis
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- Biomarkers/analysis
- Bone Marrow Cells/cytology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/metabolism
- CD5 Antigens/biosynthesis
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Division/immunology
- Cell Line
- Enzyme Precursors/physiology
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/immunology
- Hematopoietic Stem Cells/metabolism
- Herpesvirus 4, Human/immunology
- Immunoglobulin M/biosynthesis
- Immunoglobulin M/blood
- Intracellular Signaling Peptides and Proteins
- Leukosialin
- Lipopolysaccharides/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/chemistry
- Receptors, Antigen, B-Cell/deficiency
- Receptors, IgE/deficiency
- Sialoglycoproteins/biosynthesis
- Structural Homology, Protein
- Syk Kinase
- Tetradecanoylphorbol Acetate/pharmacology
- Viral Matrix Proteins/biosynthesis
- Viral Matrix Proteins/chemistry
- Viral Matrix Proteins/physiology
- Virus Latency/immunology
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Affiliation(s)
- Akiko Ikeda
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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Galler GR, Mundt C, Parker M, Pelanda R, Mårtensson IL, Winkler TH. Surface mu heavy chain signals down-regulation of the V(D)J-recombinase machinery in the absence of surrogate light chain components. ACTA ACUST UNITED AC 2004; 199:1523-32. [PMID: 15173209 PMCID: PMC2211789 DOI: 10.1084/jem.20031523] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Early B cell development is characterized by stepwise, ordered rearrangement of the immunoglobulin (Ig) heavy (HC) and light (LC) chain genes. Only one of the two alleles of these genes is used to produce a receptor, a phenomenon referred to as allelic exclusion. It has been suggested that pre–B cell receptor (pre-BCR) signals are responsible for down-regulation of the VDJH-recombinase machinery (Rag1, Rag2, and terminal deoxynucleotidyl transferase [TdT]), thereby preventing further rearrangement on the second HC allele. Using a mouse model, we show that expression of an inducible μHC transgene in Rag2−/− pro–B cells induces down-regulation of the following: (a) TdT protein, (b) a transgenic green fluorescent protein reporter reflecting endogenous Rag2 expression, and (c) Rag1 primary transcripts. Similar effects were also observed in the absence of surrogate LC (SLC) components, but not in the absence of the signaling subunit Ig-α. Furthermore, in wild-type mice and in mice lacking either λ5, VpreB1/2, or the entire SLC, the TdT protein is down-regulated in μHC+LC− pre–B cells. Surprisingly, μHC without LC is expressed on the surface of pro–/pre–B cells from λ5−/−, VpreB1−/−VpreB2−/−, and SLC−/− mice. Thus, SLC or LC is not required for μHC cell surface expression and signaling in these cells. Therefore, these findings offer an explanation for the occurrence of HC allelic exclusion in mice lacking SLC components.
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Affiliation(s)
- Gunther R Galler
- Hematopoiesis Unit, Nikolaus-Fiebiger-Center, Friedrich-Alexander University, Glueckstrasse 6, 91054 Erlangen, Germany
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Middendorp S, Hendriks RW. Cellular maturation defects in Bruton's tyrosine kinase-deficient immature B cells are amplified by premature B cell receptor expression and reduced by receptor editing. THE JOURNAL OF IMMUNOLOGY 2004; 172:1371-9. [PMID: 14734712 DOI: 10.4049/jimmunol.172.3.1371] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In the mouse, Bruton's tyrosine kinase (Btk) is essential for efficient developmental progression of CD43(+)CD2(-) large cycling into CD43(-)CD2(+) small resting pre-B cells in the bone marrow and of IgM(high) transitional type 2 B cells into IgM(low) mature B cells in the spleen. In this study, we show that the impaired induction of cell surface changes in Btk-deficient pre-B cells was still noticeable in kappa(+) immature B cells, but was largely corrected in lambda(+) immature B cells. As lambda gene rearrangements are programmed to follow kappa rearrangements and lambda expression is associated with receptor editing, we hypothesized that the transit time through the pre-B cell compartment or receptor editing may affect the extent of the cellular maturation defects in Btk-deficient B cells. To address this issue, we used 3-83 mu delta transgenic mice, which prematurely express a complete B cell receptor and therefore manifest accelerated B cell development. In Btk-deficient 3-83 mu delta mice, the IgM(+) B cells in the bone marrow exhibited a very immature phenotype (pre-BCR(+)CD43(+)CD2(-)) and were arrested at the transitional type 1 B cell stage upon arrival in the spleen. However, these cellular maturation defects were largely restored when Btk-deficient 3-83 mu delta B cells were on a centrally deleting background and therefore targeted for receptor editing. Providing an extended time window for developing B cells by enforced expression of the antiapoptotic gene Bcl-2 did not alter the Btk dependence of their cellular maturation. We conclude that premature B cell receptor expression amplifies the cellular maturation defects in Btk-deficient B cells, while extensive receptor editing reduces these defects.
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MESH Headings
- Agammaglobulinaemia Tyrosine Kinase
- Animals
- B-Lymphocyte Subsets/enzymology
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- B-Lymphocyte Subsets/pathology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Movement/genetics
- Cell Movement/immunology
- Cells, Cultured
- Clonal Deletion/genetics
- Down-Regulation/genetics
- Down-Regulation/immunology
- Gene Rearrangement, B-Lymphocyte/genetics
- Gene Rearrangement, B-Lymphocyte/immunology
- Hematopoietic Stem Cells/enzymology
- Hematopoietic Stem Cells/immunology
- Hematopoietic Stem Cells/pathology
- Immunoglobulin delta-Chains/genetics
- Immunoglobulin kappa-Chains/biosynthesis
- Immunoglobulin lambda-Chains/biosynthesis
- Immunoglobulin mu-Chains/genetics
- Lymphopenia/enzymology
- Lymphopenia/genetics
- Lymphopenia/immunology
- Lymphopenia/pathology
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Pre-B Cell Receptors
- Protein-Tyrosine Kinases/biosynthesis
- Protein-Tyrosine Kinases/deficiency
- Protein-Tyrosine Kinases/genetics
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- Proto-Oncogene Proteins c-bcl-2/genetics
- Receptors, Antigen, B-Cell/biosynthesis
- Receptors, Antigen, B-Cell/genetics
- Spleen/immunology
- Spleen/pathology
- Up-Regulation/genetics
- Up-Regulation/immunology
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Affiliation(s)
- Sabine Middendorp
- Department of Immunology, Erasmus MC Rotterdam, Rotterdam, The Netherlands
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Sato H, Saito-Ohara F, Inazawa J, Kudo A. Pax-5 Is Essential for κ Sterile Transcription during Igκ Chain Gene Rearrangement. THE JOURNAL OF IMMUNOLOGY 2004; 172:4858-65. [PMID: 15067064 DOI: 10.4049/jimmunol.172.8.4858] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pax-5 is the key regulator in B cell development. Pax-5-deficient mice show defects in B cell commitment and recombination of IgH chain gene rearrangement from DJ to VDJ. Previously, we found that Pax-5 bound to KI and KII sites, which play a crucial role in kappa-chain gene rearrangement. However, the function of Pax-5 in Ig kappa chain gene rearrangement has not been investigated. To address this issue, we newly established pre-BI cell lines expressing the pre-B cell receptor from Pax-5-deficient mice and used them in an in vitro culture system, in which kappa-chain gene rearrangement is induced by removing IL-7. By examining the Pax-5-deficient pre-BI (knockout (KO)) cells, we show in this study that, despite recombination-activating gene 1 and 2 expression, these KO cells did not rearrange the kappa-chain gene following the absence of kappa sterile transcription. Consistent with these data, fluorescent in situ hybridization analyses revealed that the J(kappa) locus in KO cells was located at the nuclear periphery as a repressive compartment. Transfection of KO cells with Pax-5 constructs indicated that the transactivation domain of Pax-5 was required for kappa sterile transcription and kappa-chain gene rearrangement. Moreover, the hormone-inducible system in KO cells demonstrated that Pax-5 directly functioned in kappa sterile transcription. These results indicate that Pax-5 is necessary for kappa sterile transcription during Ig kappa chain gene rearrangement.
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Affiliation(s)
- Hiromu Sato
- Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan
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