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Cox EM, El-Behi M, Ries S, Vogt JF, Kohlhaas V, Michna T, Manfroi B, Al-Maarri M, Wanke F, Tirosh B, Pondarre C, Lezeau H, Yogev N, Mittenzwei R, Descatoire M, Weller S, Weill JC, Reynaud CA, Boudinot P, Jouneau L, Tenzer S, Distler U, Rensing-Ehl A, König C, Staniek J, Rizzi M, Magérus A, Rieux-Laucat F, Wunderlich FT, Hövelmeyer N, Fillatreau S. AKT activity orchestrates marginal zone B cell development in mice and humans. Cell Rep 2023; 42:112378. [PMID: 37060566 DOI: 10.1016/j.celrep.2023.112378] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 12/14/2022] [Accepted: 03/27/2023] [Indexed: 04/16/2023] Open
Abstract
The signals controlling marginal zone (MZ) and follicular (FO) B cell development remain incompletely understood. Here, we show that AKT orchestrates MZ B cell formation in mice and humans. Genetic models that increase AKT signaling in B cells or abolish its impact on FoxO transcription factors highlight the AKT-FoxO axis as an on-off switch for MZ B cell formation in mice. In humans, splenic immunoglobulin (Ig) D+CD27+ B cells, proposed as an MZ B cell equivalent, display higher AKT signaling than naive IgD+CD27- and memory IgD-CD27+ B cells and develop in an AKT-dependent manner from their precursors in vitro, underlining the conservation of this developmental pathway. Consistently, CD148 is identified as a receptor indicative of the level of AKT signaling in B cells, expressed at a higher level in MZ B cells than FO B cells in mice as well as humans.
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Affiliation(s)
- Eva-Maria Cox
- Institute for Molecular Medicine Mainz, University Hospital of Mainz, 55131 Mainz, Germany
| | - Mohamed El-Behi
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France
| | - Stefanie Ries
- Deutsches Rheuma-Forschungszentrum, a Leibniz Institute, 10117 Berlin, Germany
| | - Johannes F Vogt
- Institute for Molecular Medicine Mainz, University Hospital of Mainz, 55131 Mainz, Germany
| | - Vivien Kohlhaas
- Max Planck Institute for Metabolism Research Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50931 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases (CECAD), 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP) Cologne, 50931 Cologne, Germany
| | - Thomas Michna
- Institute for Immunology, University Medical Centre of the Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Benoît Manfroi
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France
| | - Mona Al-Maarri
- Max Planck Institute for Metabolism Research Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50931 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases (CECAD), 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP) Cologne, 50931 Cologne, Germany
| | - Florian Wanke
- Institute for Molecular Medicine Mainz, University Hospital of Mainz, 55131 Mainz, Germany
| | - Boaz Tirosh
- The Hebrew University of Jerusalem, Institute for Drug Research, Jerusalem, Israel
| | - Corinne Pondarre
- Service de Pédiatrie Générale, Centre de Référence de la Drépanocytose, Centre Intercommunal de Créteil, Créteil, France; Inserm U955, Université Paris XII, Créteil, France
| | - Harry Lezeau
- Service de Pédiatrie Générale, Centre de Référence de la Drépanocytose, Centre Intercommunal de Créteil, Créteil, France; Inserm U955, Université Paris XII, Créteil, France
| | - Nir Yogev
- Faculty of Medicine, Department of Dermatology, University of Cologne, 50931 Cologne, Germany
| | - Romy Mittenzwei
- Institute for Molecular Medicine Mainz, University Hospital of Mainz, 55131 Mainz, Germany
| | - Marc Descatoire
- Laboratory of Immune Inherited Disorders, Department of Immunology and Allergology Lausanne Hospital CHUV, Lausanne, Switzerland
| | - Sandra Weller
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France
| | - Jean-Claude Weill
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France
| | - Claude-Agnès Reynaud
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France
| | - Pierre Boudinot
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350 Jouy-en-Josas, France
| | - Luc Jouneau
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350 Jouy-en-Josas, France
| | - Stefan Tenzer
- Institute for Immunology, University Medical Centre of the Johannes-Gutenberg University Mainz, Mainz, Germany; Research Centre for Immunotherapy (FZI), University Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany; Helmholtz Institute for Translational Oncology Mainz (HI-TRON Mainz), Mainz, Germany
| | - Ute Distler
- Institute for Immunology, University Medical Centre of the Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Anne Rensing-Ehl
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christoph König
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; University of Freiburg, Faculty of Biology, Schaenzlestrasse 1, 79104 Freiburg, Germany
| | - Julian Staniek
- Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marta Rizzi
- Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Division of Clinical and Experimental Immunology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Aude Magérus
- Université Paris Cité, Institut Imagine, Laboratory of Immunogenetics of Pediatric Autoimmune Diseases, INSERM UMR 1163, 75015 Paris, France
| | - Frederic Rieux-Laucat
- Université Paris Cité, Institut Imagine, Laboratory of Immunogenetics of Pediatric Autoimmune Diseases, INSERM UMR 1163, 75015 Paris, France
| | - F Thomas Wunderlich
- Max Planck Institute for Metabolism Research Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50931 Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-associated Diseases (CECAD), 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP) Cologne, 50931 Cologne, Germany
| | - Nadine Hövelmeyer
- Institute for Molecular Medicine Mainz, University Hospital of Mainz, 55131 Mainz, Germany; Research Centre for Immunotherapy (FZI), University Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany.
| | - Simon Fillatreau
- Institut Necker Enfants Malades, INSERM U1151-CNRS UMR 8253, 156-160, rue de Vaugirard, 75015 Paris, France; Université de Paris Cité, Paris Descartes, Faculté de Médecine, Paris, France; AP-HP, Hôpital Necker Enfants Malades, Paris, France.
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2
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Steinmetz TD, Schlötzer-Schrehardt U, Hearne A, Schuh W, Wittner J, Schulz SR, Winkler TH, Jäck HM, Mielenz D. TFG is required for autophagy flux and to prevent endoplasmic reticulum stress in CH12 B lymphoma cells. Autophagy 2020; 17:2238-2256. [PMID: 32910713 DOI: 10.1080/15548627.2020.1821546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plasma cells depend on quality control of newly synthesized antibodies in the endoplasmic reticulum (ER) via macroautophagy/autophagy and proteasomal degradation. The cytosolic adaptor protein TFG (Trk-fused gene) regulates ER-Golgi transport, the secretory pathway and proteasome activity in non-immune cells. We show here that TFG is upregulated during lipopolysaccharide- and CpG-induced differentiation of B1 and B2 B cells into plasmablasts, with the highest expression of TFG in mature plasma cells. CRISPR-CAS9-mediated gene disruption of tfg in the B lymphoma cell line CH12 revealed increased apoptosis, which was reverted by BCL2 but even more by ectopic TFG expression. Loss of TFG disrupted ER structure, leading to an expanded ER and increased expression of ER stress genes. When compared to wild-type CH12 cells, tfg KO CH12 cells were more sensitive toward ER stress induced by tunicamycin, monensin and proteasome inhibition or by expression of an ER-bound immunoglobulin (Ig) μ heavy (µH) chain. CH12 tfg KO B cells displayed more total LC3, lower LC3-II turnover and increased numbers and size of autophagosomes. Tandem-fluorescent-LC3 revealed less accumulation of GFP-LC3 in starved and chloroquine-treated CH12 tfg KO B cells. The GFP:RFP ratio of tandem-fluorescent-LC3 was higher in tunicamycin-treated CH12 tfg KO B cells, suggesting less autophagy flux during induced ER stress. Based on these data, we suggest that TFG controls autophagy flux in CH12 B cells and propose that TFG is a survival factor that alleviates ER stress through the support of autophagy flux in activated B cells and mature plasma cells.Abbreviations: Ab, antibody; Ag, antigen; ASC, antibody-secreting cells; ATG, autophagy-related; BCR, B cell receptor; COPII, coat protein complex II; CpG, non-methylated CpG oligonucleotide; ER, endoplasmic reticulum; ERAD, ER-associated degradation; FO, follicular; GFP, green fluorescent protein; HC, heavy chain; Ig, immunoglobulin; IRES, internal ribosomal entry site; LC, light chain; MZ, marginal zone; NFKB, nuclear factor of kappa light polypeptide gene enhancer in B cells; TLR, toll-like receptor; UPR, unfolded protein response.
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Affiliation(s)
- Tobit D Steinmetz
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | | | - Abigail Hearne
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Wolfgang Schuh
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Jens Wittner
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Sebastian R Schulz
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas H Winkler
- Department of Biology, Chair of Genetics, Nikolaus-Fiebiger-Zentrum, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Hans-Martin Jäck
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Dirk Mielenz
- Division of Molecular Immunology, Department of Internal Medicine 3, Nikolaus-Fiebiger-Zentrum, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
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3
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Hao L, Marshall AJ, Liu L. Bam32/DAPP1-Dependent Neutrophil Reactive Oxygen Species in WKYMVm-Induced Microvascular Hyperpermeability. Front Immunol 2020; 11:1028. [PMID: 32536926 PMCID: PMC7267069 DOI: 10.3389/fimmu.2020.01028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/29/2020] [Indexed: 11/13/2022] Open
Abstract
B cell adaptor molecule of 32 kDa (Bam32), known as dual adapter for phosphotyrosine and 3-phosphoinositides 1 (DAPP1), has been implicated in regulating lymphocyte proliferation and recruitment during inflammation. However, its role in neutrophils during inflammation remains unknown. Using intravital microscopy, we examined the role of Bam32 in formyl peptide receptor agonist WKYMVm-induced permeability changes in post-capillary venules and assessed simultaneously neutrophil adhesion and emigration in cremaster muscles of Bam32-deficient (Bam32−/−) and wild-type (WT) control mice. We observed significantly reduced WKYMVm-induced microvascular hyperpermeability accompanied by markedly decreased neutrophil emigration in Bam32−/− mice. The Bam32-specific decrease in WKYMVm-induced hyperpermeability was neutrophil-dependent as this was verified in bone marrow transplanted chimeric mice. We discovered that Bam32 was critically required for WKYMVm-induced intracellular and extracellular production of reactive oxygen species (ROS) in neutrophils. Pharmacological scavenging of ROS eliminated the differences in WKYMVm-induced hyperpermeability between Bam32−/− and WT mice. Deficiency of Bam32 decreased WKYMVm-induced ERK1/2 but not p38 or JNK phosphorylation in neutrophils. Inhibition of ERK1/2 signaling cascade suppressed WKYMVm-induced ROS generation in WT neutrophils and microvascular hyperpermeability in WT mice. In conclusion, our study reveals that Bam32-dependent, ERK1/2-involving ROS generation in neutrophils is critical in WKYMVm-induced microvascular hyperpermeability during neutrophil recruitment.
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Affiliation(s)
- Li Hao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Aaron J Marshall
- Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Lixin Liu
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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4
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The impact of CDK inhibition in human malignancies associated with pronounced defects in apoptosis: advantages of multi-targeting small molecules. Future Med Chem 2012; 4:395-424. [DOI: 10.4155/fmc.12.12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Malignant cells in chronic lymphocytic leukemia (CLL) and related diseases are heterogeneous and consist primarily of long-lived resting cells in the periphery and a minor subset of dividing cells in proliferating centers. Both cell populations have different molecular signatures that play a major role in determining their sensitivity to therapy. Contemporary approaches to treating CLL are heavily reliant on cytotoxic chemotherapeutics. However, none of the current treatment regimens can be considered curative. Pharmacological CDK inhibitors have extended the repertoire of potential drugs for CLL. Multi-targeted CDK inhibitors affect CDKs involved in regulating both cell cycle progression and transcription. Their interference with transcriptional elongation represses anti-apoptotic proteins and, thus, promotes the induction of apoptosis. Importantly, there is evidence that treatment with CDK inhibitors can overcome resistance to therapy. The pharmacological CDK inhibitors have great potential for use in combination with other therapeutics and represent promising tools for the development of new curative treatments for CLL.
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5
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Orozco G, Barton A. Update on the genetic risk factors for rheumatoid arthritis. Expert Rev Clin Immunol 2010; 6:61-75. [PMID: 20383892 DOI: 10.1586/eci.09.72] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Rheumatoid arthritis (RA) is a complex disease, meaning that multiple genetic variants, environmental factors and random events interact to trigger pathological pathways. Although many of these etiological factors have not yet been identified, recent groundbreaking advances have expanded our knowledge about the genetic factors that contribute to RA. Here, we review the most recent findings on the genetic risk factors for RA. First, we give an overview of the genetics of RA and briefly describe the susceptibility loci discovered prior to the availability of genome-wide association studies (GWAS). Second, we focus on the newly discovered RA loci that have arisen from GWAS in populations of European ancestry. Through these studies, the number of established RA susceptibility loci has now grown to 13. Third, we discuss several important issues emerging from GWAS, such as ethnic heterogeneity and shared autoimmunity risk loci. Finally, we discuss what still needs to be accomplished before a more complete picture of the genetic risk to RA can be attained.
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Affiliation(s)
- Gisela Orozco
- Arthritis Research Campaign Epidemiology Unit, The University of Manchester, Manchester Academic Health Science Centre, Stopford Building, Oxford Road, Manchester M13 9PT, UK.
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6
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Rothstein TL, Guo B. Receptor crosstalk: reprogramming B cell receptor signalling to an alternate pathway results in expression and secretion of the autoimmunity-associated cytokine, osteopontin. J Intern Med 2009; 265:632-43. [PMID: 19493057 PMCID: PMC2774770 DOI: 10.1111/j.1365-2796.2009.02103.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Receptor crosstalk: reprogramming B cell receptor signalling to an alternate pathway results in expression and secretion of the autoimmunity-associated cytokine, osteopontin (Review). J Intern Med 2009; 265: 632-643.Intracellular signalling emanating from the B-cell antigen receptor is considered to follow a discrete course that requires participation by a set of mediators, grouped together as the signalosome, in order for downstream events to occur. Recent work indicates that this paradigm is true only for naïve B cells. Following engagement of the IL-4 receptor, a new, alternate pathway for B-cell receptor (BCR)-triggered intracellular signalling is established that bypasses the need for signalosome elements and operates in parallel with the classical, signalosome-dependent pathway. Reliance on Lyn and sensitivity to rottlerin by the former, but not the latter, distinguishes these two pathways. The advent of alternate pathway signalling leads to production and secretion by B cells of osteopontin (Opn). As Opn is a polyclonal B-cell activator that is strongly associated with a number of autoimmune diseases including lupus and rheumatoid arthritis, this novel finding is likely to be clinically relevant. Our results highlight the potential role of B-cell-derived Opn in immunity and autoimmunity and suggest that stress-related IL-4 expression might act to strengthen immunoglobulin secretion at the risk of autoantibody formation. Further, these results illustrate receptor crosstalk in the form of reprogramming, whereby engagement of one receptor (IL-4R) produces an effect that persists after the original ligand (IL-4) is removed and results in alteration of the pathway, and outcome, of signalling via a second receptor (BCR) following its activation.
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Affiliation(s)
- T L Rothstein
- Center for Oncology and Cell Biology, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA.
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7
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Richards S, Watanabe C, Santos L, Craxton A, Clark EA. Regulation of B-cell entry into the cell cycle. Immunol Rev 2008; 224:183-200. [PMID: 18759927 DOI: 10.1111/j.1600-065x.2008.00652.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
B cells are induced to enter the cell cycle by stimuli including ligation of the B-cell receptor (BCR) complex and Toll-like receptor (TLR) agonists. This review discusses the contribution of several molecules, which act at distinct steps in B-cell activation. The adapter molecule Bam32 (B-lymphocyte adapter of 32 kDa) helps promote BCR-induced cell cycle entry, while the secondary messenger superoxide has the opposite effect. Bam32 and superoxide may fine tune BCR-induced activation by competing for the same limited resources, namely Rac1 and the plasma membrane phospholipid PI(3,4)P(2). The co-receptor CD22 can inhibit BCR-induced proliferation by binding to novel CD22 ligands. Finally, regulators of B-cell survival and death also play roles in B-cell transit through the cell cycle. Caspase 6 negatively regulates CD40- and TLR-dependent G(1) entry, while acting later in the cell cycle to promote S-phase entry. Caspase 6 deficiency predisposes B cells to differentiate rather than proliferate after stimulation. Bim, a pro-apoptotic Bcl-2 family member, exerts a positive regulatory effect on cell cycle entry, which is opposed by Bcl-2. New insights into what regulates B-cell transit through the cell cycle may lead to thoughtful design of highly selective drugs that target pathogenic B cells.
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Affiliation(s)
- Sabrina Richards
- Department of Immunology and Microbiology, University of Washington, Seattle, WA 98195, USA
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8
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Rheumatoid arthritis susceptibility loci at chromosomes 10p15, 12q13 and 22q13. Nat Genet 2008; 40:1156-9. [PMID: 18794857 DOI: 10.1038/ng.218] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 07/14/2008] [Indexed: 12/26/2022]
Abstract
The WTCCC study identified 49 SNPs putatively associated with rheumatoid arthritis at P = 1 x 10(-4) - 1 x 10(-5) (tier 3). Here we show that three of these SNPs, mapping to chromosome 10p15 (rs4750316), 12q13 (rs1678542) and 22q13 (rs3218253), are also associated (trend P = 4 x 10(-5), P = 4 x 10(-4) and P = 4 x 10(-4), respectively) in a validation study of 4,106 individuals with rheumatoid arthritis and an expanded reference group of 11,238 subjects, confirming them as true susceptibility loci in individuals of European ancestry.
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Engelke M, Engels N, Dittmann K, Stork B, Wienands J. Ca(2+) signaling in antigen receptor-activated B lymphocytes. Immunol Rev 2007; 218:235-46. [PMID: 17624956 DOI: 10.1111/j.1600-065x.2007.00539.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
B cells respond to antigen stimulation with mobilization of the Ca(2+) second messenger in two phases operated by two distinct sets of effector proteins. First, an antigen receptor-specific Ca(2+) initiation complex is assembled, activated, and targeted to the plasma membrane to trigger the transient release of Ca(2+) from intracellular stores of the endoplasmic reticulum. Second, more ubiquitously expressed Ca(2+) channels of the plasma membrane are opened to allow for sustained Ca(2+) influx from the extracellular medium. Depending on the developmental stage of the B cell, the kinetics and profile of the two phases are adjusted at multiple levels of positive and negative regulation. A molecular basis for the Ca(2+) signaling plasticity is provided by cytosolic and transmembrane adapter proteins. They act as signal organizers, which control enzyme/substrate interactions by directing the different signaling modules into specific subcellular compartments. These arrangements orchestrate a graduated activation of Ca(2+)-sensitive downstream pathways, which ultimately determine appropriate cellular responses, namely elimination of autoreactive B cells or proliferation and differentiation of immunocompetent B cells into antibody-secreting plasma cells.
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Affiliation(s)
- Michael Engelke
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany
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10
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Dye JR, Palvanov A, Guo B, Rothstein TL. B Cell Receptor Cross-Talk: Exposure to Lipopolysaccharide Induces an Alternate Pathway for B Cell Receptor-Induced ERK Phosphorylation and NF-κB Activation. THE JOURNAL OF IMMUNOLOGY 2007; 179:229-35. [PMID: 17579042 DOI: 10.4049/jimmunol.179.1.229] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BCR signaling in naive B cells depends on the function of signalosome mediators; however, prior engagement of CD40 or of IL-4R produces an alternate signaling pathway in which Bruton's tyrosine kinase, PI3K, phospholipase Cgamma2, and protein kinase Cbeta are no longer required for BCR-induced downstream events. To explore the range of mediators capable of producing such an alternate pathway for BCR signaling, we examined the TLR4 agonist, LPS. B cell treatment with LPS at relatively low doses altered subsequent BCR signaling such that ERK phosphorylation and NF-kappaB activation occurred in a PI3K-independent manner. This effect of LPS extended to MEK phosphorylation and IkappaBalpha degradation, and it developed slowly over a period of 16-24 h. The involvement of TLRs is suggested by similar effects observed with a structurally distinct TLR agonist, PAM3CSK4 and by the need for MyD88 for induction of alternate BCR signaling by LPS. Thus, LPS-mediated TLR engagement produces an alternate pathway for BCR-triggered signal propagation that differs from the classical, signalosome-dependent pathway.
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Affiliation(s)
- John R Dye
- Department of Pathology, Boston University School of Medicine, Boston, MA 02118, USA
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11
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Hou P, Araujo E, Zhao T, Zhang M, Massenburg D, Veselits M, Doyle C, Dinner AR, Clark MR. B cell antigen receptor signaling and internalization are mutually exclusive events. PLoS Biol 2006; 4:e200. [PMID: 16719564 PMCID: PMC1470458 DOI: 10.1371/journal.pbio.0040200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 04/13/2006] [Indexed: 02/03/2023] Open
Abstract
Engagement of the B cell antigen receptor initiates two concurrent processes, signaling and receptor internalization. While both are required for normal humoral immune responses, the relationship between these two processes is unknown. Herein, we demonstrate that following receptor ligation, a small subpopulation of B cell antigen receptors are inductively phosphorylated and selectively retained at the cell surface where they can serve as scaffolds for the assembly of signaling molecules. In contrast, the larger population of non-phosphorylated receptors is rapidly endocytosed. Each receptor can undergo only one of two mutually exclusive fates because the tyrosine-based motifs that mediate signaling when phosphorylated mediate internalization when not phosphorylated. Mathematical modeling indicates that the observed competition between receptor phosphorylation and internalization enhances signaling responses to low avidity ligands.
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Affiliation(s)
- Ping Hou
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
| | - Elizabeth Araujo
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
| | - Tong Zhao
- 3Department of Chemistry, University of Chicago, Chicago, Illinois, United States of America
- 4Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, United States of America
- 5James Franck Institute, University of Chicago, Chicago, Illinois, United States of America
| | - Miao Zhang
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
| | - Don Massenburg
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
| | - Margaret Veselits
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
| | - Colleen Doyle
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
| | - Aaron R Dinner
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
- 3Department of Chemistry, University of Chicago, Chicago, Illinois, United States of America
- 4Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois, United States of America
- 5James Franck Institute, University of Chicago, Chicago, Illinois, United States of America
| | - Marcus R Clark
- 1Department of Medicine and Section of Rheumatology, University of Chicago, Chicago, Illinois, United States of America
- 2Committee on Immunology, University of Chicago, Chicago, Illinois, United States of America
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Herrin BR, Justement LB. Expression of the adaptor protein hematopoietic Src homology 2 is up-regulated in response to stimuli that promote survival and differentiation of B cells. THE JOURNAL OF IMMUNOLOGY 2006; 176:4163-72. [PMID: 16547253 DOI: 10.4049/jimmunol.176.7.4163] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Analysis of hematopoietic Src homology 2 (HSH2) protein expression in mouse immune cells demonstrated that it is expressed at low levels in resting B cells but not T cells or macrophages. However, HSH2 expression is up-regulated within 6-12 h in response to multiple stimuli that promote activation, differentiation, and survival of splenic B cells. HSH2 expression is increased in response to anti-CD40 mAb, the TLR ligands LPS and CpG DNA, and B lymphocyte stimulator (BLyS), a key regulator of peripheral B cell survival and homeostasis. Stimulation of B cells with anti-CD40 mAb, LPS, CpG DNA, or BLyS has previously been shown to induce activation of NF-kappaB. In agreement with this finding, up-regulation of HSH2 expression in response to these stimuli is blocked by inhibitors of NF-kappaB activation and is potentiated by stimulation with PMA, suggesting that HSH2 expression is dependent on NF-kappaB activation. In contrast to CD40, BAFF receptor, TLR4, and TLR9 mediated signaling, stimulation of splenic B cells via the BCR was not observed to induce expression of HSH2 unless the cells had been stimulated previously through CD40. Finally, HSH2 expression is down-regulated in splenic B cells in response to stimulation with IL-21, which has been shown to induce apoptosis, even in the presence of anti-CD40 mAb, LPS, or CpG DNA. IL-21 stimulation also results in down-regulation of antiapoptotic proteins such as Bcl-x(L) and up-regulation of proapoptotic proteins like Bim. Therefore, HSH2 expression is coordinately up-regulated with known antiapoptotic molecules and directly correlates with B cell survival.
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Affiliation(s)
- Brantley R Herrin
- Division of Developmental and Clinical Immunology, Department of Microbiology, University of Alabama, Birmingham, 35294, USA
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Bilancio A, Okkenhaug K, Camps M, Emery JL, Ruckle T, Rommel C, Vanhaesebroeck B. Key role of the p110δ isoform of PI3K in B-cell antigen and IL-4 receptor signaling: comparative analysis of genetic and pharmacologic interference with p110δ function in B cells. Blood 2006; 107:642-50. [PMID: 16179367 DOI: 10.1182/blood-2005-07-3041] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
AbstractMouse gene–targeting studies have documented a central role of the p110δ isoform of phosphoinositide 3-kinase (PI3K) in B-cell development and function. A defect in B-cell antigen receptor (BCR) signaling is key to this B-cell phenotype. Here we further characterize this signaling defect and report that a p110δ-selective small molecule inhibitor mirrors the effect of genetic inactivation of p110δ in BCR signaling. p110δ activity is indispensable for BCR-induced DNA synthesis and phosphorylation of Akt/protein kinase B (PKB), forkhead transcription factor/forkhead box O3a (FOXO3a), and p70 S6 kinase (p70 S6K), with modest effects on the phosphorylation of glycogen synthase kinase 3 α/β (GSK3α/β) and extracellular signal-regulated kinase (Erk). The PI3K-dependent component of intracellular calcium mobilization also completely relies on p110δ catalytic activity. Resting B cells with inactive p110δ fail to enter the cell cycle, correlating with an incapacity to up-regulate the expression of cyclins D2, A, and E, and to phosphorylate the retinoblastoma protein (Rb). p110δ is also critical for interleukin 4 (IL-4)–induced phosphorylation of Akt/PKB and FOXO3a, and protection from apoptosis. Taken together, these data show that defects observed in p110δ mutant mice are not merely a consequence of altered B-cell differentiation, and emphasize the potential utility of p110δ as a drug target in autoimmune diseases in which B cells play a crucial role.
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Affiliation(s)
- Antonio Bilancio
- Ludwig Institute for Cancer Research, 91 Riding House Street, London, W1W 7BS, United Kingdom
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Guo B, Rothstein TL. B cell receptor (BCR) cross-talk: IL-4 creates an alternate pathway for BCR-induced ERK activation that is phosphatidylinositol 3-kinase independent. THE JOURNAL OF IMMUNOLOGY 2005; 174:5375-81. [PMID: 15843535 DOI: 10.4049/jimmunol.174.9.5375] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IL-4 has pleiotropic effects on B cells. These effects include alteration of subsequent BCR-triggered responses. To identify a molecular basis for this receptor cross-talk, we examined ERK activation and NF-kappaB induction. We found that treatment with IL-4, but not other cytokines, affected subsequent BCR signaling by creating a new pathway in which the need for PI3K in ERK activation was eliminated. In contrast, the need for PI3K in NF-kappaB induction was not altered. The new pathway for ERK required time to develop, depended on STAT6, and was blocked by inhibition of macromolecular synthesis. As in the classical pathway, BCR-induced ERK activation in the new, PI3K-independent pathway required MEK and was reflected in c-Raf. Thus, IL-4 promotes an alternate pathway through which BCR is coupled to Raf/MEK/ERK that may function to heighten the responsiveness of B cells during times of immunological stress.
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Affiliation(s)
- Benchang Guo
- Department of Medicine, Boston University School of Medicine, MA 02118, USA
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Mizuno T, Rothstein TL. B cell receptor (BCR) cross-talk: CD40 engagement enhances BCR-induced ERK activation. THE JOURNAL OF IMMUNOLOGY 2005; 174:3369-76. [PMID: 15749869 DOI: 10.4049/jimmunol.174.6.3369] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bystander B cells may be initially stimulated through CD40, which enhances susceptibility to Fas-mediated apoptosis, before encountering Ag, which produces Fas resistance. A key issue in this process is to what extent CD40 cross-talk might affect subsequent BCR signaling. It has previously been shown that CD40 engagement bypasses or mitigates the need for Bruton's tyrosine kinase in subsequent BCR signaling for NF-kappaB activation. However, the full extent of the effects of CD40 on BCR signaling has not been delineated. In the present study we evaluated the possibility that CD40-mediated cross-talk also affects another principal outcome of BCR signaling: MAPK activation. We found that prior stimulation of primary murine B cells with CD40L markedly enhanced the level of ERK and JNK (but not p38 MAPK) phosphorylation produced by subsequently added anti-Ig Ab, and much, but not all, of this enhancement was independent of PI3K and phospholipase C. CD40L treatment similarly enhanced BCR-induced MAPK kinase (MEK) phosphorylation, and MEK was required for enhancement of ERK. Although BCR-induced c-Raf phosphorylation was also enhanced by prior CD40L treatment, c-Raf was not required for MEK/ERK phosphorylation. These results identify a novel system of receptor cross-talk between CD40 and BCR and indicate that the effects of CD40 engagement on subsequent BCR stimulation spread beyond NF-kappaB to involve the MAPK pathway.
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Affiliation(s)
- Takuya Mizuno
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
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Abstract
Phosphoinositide 3-kinase (PI3K) activation is essential for lymphocyte proliferation driven by receptors for antigen, costimulatory ligands and cytokines. The lipid products of PI3K contribute to the assembly of membrane-associated signaling complexes by promoting recruitment of selected proteins from the cytoplasm. Many proteins possess domains that are able to bind selectively to PI3K products. Different 'PI3K effector' proteins are coupled to distinct biological responses, depending on cell type and on the receptor that is engaged. In B cells and T cells, Tec-family tyrosine kinases and Akt serine/threonine kinases are emerging as crucial mediators of proliferation and survival signals downstream of PI3K. Of particular interest is recent evidence that PI3K signaling controls increases in lymphocyte size and metabolic activity that accompany cell cycle progression.
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Affiliation(s)
- David A Fruman
- University of California, Irvine, Department of Molecular Biology and Biochemistry, 3242 McGaugh Hall, Irvine, California 92697-3900, USA.
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Herrin BR, Groeger AL, Justement LB. The adaptor protein HSH2 attenuates apoptosis in response to ligation of the B cell antigen receptor complex on the B lymphoma cell line, WEHI-231. J Biol Chem 2004; 280:3507-15. [PMID: 15569688 DOI: 10.1074/jbc.m407690200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Signals transduced by the B cell antigen receptor (BCR) play a central role in regulating the functional response of the cell to antigen. Depending on the nature of the antigenic signal and the developmental or differentiation state of the B cell, antigen receptor signaling can promote either apoptosis or survival and activation. Understanding the molecular mechanisms underlying BCR-mediated apoptosis constitutes an important area of research because aberrations in programmed cell death can result in the development of autoimmunity or cancer. Expression of the adaptor protein hematopoietic Src homology 2 (HSH2) was found to significantly decrease BCR-mediated apoptosis in the murine WEHI-231 cell line. Analysis of signal transduction pathways activated in response to BCR ligation revealed that HSH2 does not significantly alter total protein tyrosine phosphorylation or Ca2+ mobilization. HSH2 does not potentiate the activation-dependent phosphorylation of AKT either. With respect to MAPK activation, HSH2 was not observed to alter the activation of ERK or p38 in response to BCR ligation, but it does significantly potentiate JNK activation. Analysis of processes directly associated with apoptosis revealed that HSH2 inhibits mitochondrial depolarization to a significant degree, whereas it has only a slight effect on caspase activation and poly ADP-ribose polymerase cleavage. BCR-induced apoptosis of WEHI-231 cells is associated with the loss of endogenous HSH2 expression within 12 h, whereas inhibition of apoptosis in response to CD40-mediated signaling leads to stabilization of HSH2 expression. Thus, endogenous HSH2 expression correlates directly with survival of WEHI-231 cells, which supports the hypothesis that HSH2 modulates the apoptotic response through its ability to directly or indirectly promote mitochondrial stability.
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Affiliation(s)
- Brantley R Herrin
- Division of Developmental and Clinical Immunology, Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Niiro H, Allam A, Stoddart A, Brodsky FM, Marshall AJ, Clark EA. The B lymphocyte adaptor molecule of 32 kilodaltons (Bam32) regulates B cell antigen receptor internalization. THE JOURNAL OF IMMUNOLOGY 2004; 173:5601-9. [PMID: 15494510 DOI: 10.4049/jimmunol.173.9.5601] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The B lymphocyte adaptor molecule of 32 kDa (Bam32) is an adaptor that plays an indispensable role in BCR signaling. In this study, we found that upon BCR ligation, Bam32 is recruited to the plasma membrane where it associates with BCR complexes and redistributes and internalizes with BCRs. BCR ligation induced colocalization of Bam32 with lipid rafts, clathrin, and actin filaments. An inhibitor of Src family protein tyrosine kinases (PTKs) blocked both BCR-induced tyrosine phosphorylation of Bam32 and BCR internalization. Moreover, BCR internalization is impaired in Bam32-/- and Lyn-/- cells, and expression of Bam32 with a mutation of its tyrosine phosphorylation site (Y139F) inhibited BCR internalization. These data suggest that Bam32 functions downstream of Src family PTKs to regulate BCR internalization. Bam32 deficiency does not affect tyrosine phosphorylation of clathrin or the association of clathrin with lipid rafts upon BCR cross-linking. However, BCR-induced actin polymerization is impaired in Bam32-/- cells. Collectively, these findings indicate a novel role of Bam32 in connecting Src family PTKs to BCR internalization by an actin-dependent mechanism.
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Affiliation(s)
- Hiroaki Niiro
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
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Chiles TC. Regulation and Function of Cyclin D2 in B Lymphocyte Subsets. THE JOURNAL OF IMMUNOLOGY 2004; 173:2901-7. [PMID: 15322145 DOI: 10.4049/jimmunol.173.5.2901] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abs produced by B lymphocytes play an essential role in humoral immunity against pathogens. This response is dependent upon the extent of genome replication, which in turn allows clonal expansion of Ag-specific B cell precursors. Thus, there is considerable interest in understanding how naive B cells commit to genome replication following Ag challenge. The BCR is a key regulator of B cell growth responses in the bone marrow and the periphery. The importance of identifying BCR-coupled signaling networks and their cell cycle targets is underscored by the recognition that aberrant cell cycle control can lead to lymphoproliferative disorders or lymphoid malignancies. This review focuses on recent progress toward understanding the function of cyclin D2 in cell cycle control, and in the development of murine B lymphocytes.
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Affiliation(s)
- Thomas C Chiles
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA.
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