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Wright JA, Bazile C, Clark ES, Carlesso G, Boucher J, Kleiman E, Mahmoud T, Cheng LI, López-Rodríguez DM, Satterthwaite AB, Altman NH, Greidinger EL, Khan WN. Impaired B Cell Apoptosis Results in Autoimmunity That Is Alleviated by Ablation of Btk. Front Immunol 2021; 12:705307. [PMID: 34512628 PMCID: PMC8427801 DOI: 10.3389/fimmu.2021.705307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/30/2021] [Indexed: 01/23/2023] Open
Abstract
While apoptosis plays a role in B-cell self-tolerance, its significance in preventing autoimmunity remains unclear. Here, we report that dysregulated B cell apoptosis leads to delayed onset autoimmune phenotype in mice. Our longitudinal studies revealed that mice with B cell-specific deletion of pro-apoptotic Bim (BBimfl/fl ) have an expanded B cell compartment with a notable increase in transitional, antibody secreting and recently described double negative (DN) B cells. They develop greater hypergammaglobulinemia than mice lacking Bim in all cells and accumulate several autoantibodies characteristic of Systemic Lupus Erythematosus (SLE) and related Sjögren's Syndrome (SS) including anti-nuclear, anti-Ro/SSA and anti-La/SSB at a level comparable to NODH2h4 autoimmune mouse model. Furthermore, lymphocytes infiltrated the tissues including submandibular glands and formed follicle-like structures populated with B cells, plasma cells and T follicular helper cells indicative of ongoing immune reaction. This autoimmunity was ameliorated upon deletion of Bruton's tyrosine kinase (Btk) gene, which encodes a key B cell signaling protein. These studies suggest that Bim-mediated apoptosis suppresses and B cell tyrosine kinase signaling promotes B cell-mediated autoimmunity.
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Affiliation(s)
- Jacqueline A. Wright
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Cassandra Bazile
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Emily S. Clark
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Gianluca Carlesso
- Early Oncology Discovery, Early Oncology R&D, AstraZeneca, Gaithersburg, MD, United States
| | - Justin Boucher
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Eden Kleiman
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Tamer Mahmoud
- Early Oncology Discovery, Early Oncology R&D, AstraZeneca, Gaithersburg, MD, United States
| | - Lily I. Cheng
- Oncology Safety/Pathology, Clinical Pharmacology and Safety Sciences, AstraZeneca, Gaithersburg, MD, United States
| | - Darlah M. López-Rodríguez
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Anne B. Satterthwaite
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Norman H. Altman
- Department of Pathology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Eric L. Greidinger
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Wasif N. Khan
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, United States
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Berry CT, Liu X, Myles A, Nandi S, Chen YH, Hershberg U, Brodsky IE, Cancro MP, Lengner CJ, May MJ, Freedman BD. BCR-Induced Ca 2+ Signals Dynamically Tune Survival, Metabolic Reprogramming, and Proliferation of Naive B Cells. Cell Rep 2020; 31:107474. [PMID: 32294437 PMCID: PMC7301411 DOI: 10.1016/j.celrep.2020.03.038] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/10/2020] [Accepted: 03/12/2020] [Indexed: 01/06/2023] Open
Abstract
B cell receptor (BCR) engagement induces naive B cells to differentiate and perform critical immune-regulatory functions. Acquisition of functional specificity requires that a cell survive, enter the cell cycle, and proliferate. We establish that quantitatively distinct Ca2+ signals triggered by variations in the extent of BCR engagement dynamically regulate these transitions by controlling nuclear factor κB (NF-κB), NFAT, and mTORC1 activity. Weak BCR engagement induces apoptosis by failing to activate NF-κB-driven anti-apoptotic gene expression. Stronger signals that trigger more robust Ca2+ signals promote NF-κB-dependent survival and NFAT-, mTORC1-, and c-Myc-dependent cell-cycle entry and proliferation. Finally, we establish that CD40 or TLR9 costimulation circumvents these Ca2+-regulated checkpoints of B cell activation and proliferation. As altered BCR signaling is linked to autoimmunity and B cell malignancies, these results have important implications for understanding the pathogenesis of aberrant B cell activation and differentiation and therapeutic approaches to target these responses.
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Affiliation(s)
- Corbett T Berry
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; School of Biomedical Engineering, Science and Health Systems, Drexel University, PA 19104, USA
| | - Xiaohong Liu
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arpita Myles
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Satabdi Nandi
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Youhai H Chen
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Uri Hershberg
- School of Biomedical Engineering, Science and Health Systems, Drexel University, PA 19104, USA; Department of Human Biology, Faculty of Sciences, University of Haifa, Haifa 3498838, Israel
| | - Igor E Brodsky
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael P Cancro
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher J Lengner
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; University of Pennsylvania Institute for Regenerative Medicine, Philadelphia, PA 19104, USA
| | - Michael J May
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bruce D Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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3
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Zhang JY, Zhang PP, Zhou WP, Yu JY, Yao ZH, Chu JF, Yao SN, Wang C, Lone W, Xia QX, Ma J, Yang SJ, Liu KD, Dong ZG, Guo YJ, Smith LM, McKeithan TW, Chan WC, Iqbal J, Liu YY. L-Type Cav 1.2 Calcium Channel-α-1C Regulates Response to Rituximab in Diffuse Large B-Cell Lymphoma. Clin Cancer Res 2019; 25:4168-4178. [PMID: 30824586 DOI: 10.1158/1078-0432.ccr-18-2146] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/28/2018] [Accepted: 02/26/2019] [Indexed: 11/16/2022]
Abstract
PURPOSE One third of patients with diffuse large B-cell lymphoma (DLBCL) succumb to the disease partly due to rituximab resistance. Rituximab-induced calcium flux is an important inducer of apoptotic cell death, and we investigated the potential role of calcium channels in rituximab resistance. EXPERIMENTAL DESIGN The distinctive expression of calcium channel members was compared between patients sensitive and resistant to rituximab, cyclophosphamide, vincristine, doxorubicin, prednisone (RCHOP) regimen. The observation was further validated through mechanistic in vitro and in vivo studies using cell lines and patient-derived xenograft mouse models. RESULTS A significant inverse correlation was observed between CACNA1C expression and RCHOP resistance in two independent DLBCL cohorts, and CACNA1C expression was an independent prognostic factor for RCHOP resistance after adjusting for International Prognostic Index, cell-of-origin classification, and MYC/BCL2 double expression. Loss of CACNA1C expression reduced rituximab-induced apoptosis and tumor shrinkage. We further demonstrated direct interaction of CACNA1C with CD20 and its role in CD20 stabilization. Functional modulators of L-type calcium channel showed expected alteration in rituximab-induced apoptosis and tumor suppression. Furthermore, we demonstrated that CACNA1C expression was directly regulated by miR-363 whose high expression is associated with worse prognosis in DLBCL. CONCLUSIONS We identified the role of CACNA1C in rituximab resistance, and modulating its expression or activity may alter rituximab sensitivity in DLBCL.
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Affiliation(s)
- Jiu-Yang Zhang
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Pei-Pei Zhang
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Wen-Ping Zhou
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Jia-Yu Yu
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Zhi-Hua Yao
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Jun-Feng Chu
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Shu-Na Yao
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Cheng Wang
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Waseem Lone
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Qing-Xin Xia
- Department of Molecule and Pathology, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Jie Ma
- Department of Molecule and Pathology, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Shu-Jun Yang
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Kang-Dong Liu
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan, China.,Department of Pathophysiology, Basic Medical College, Zhengzhou University, Zhengzhou, Henan, China
| | - Zi-Gang Dong
- China-US (Henan) Hormel Cancer Institute, Zhengzhou, Henan, China
| | - Yong-Jun Guo
- Department of Molecule and Pathology, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China
| | - Lynette M Smith
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, Nebraska
| | - Timothy W McKeithan
- Department of Pathology, City of Hope National Medical Center, Duarte, California
| | - Wing C Chan
- Department of Pathology, City of Hope National Medical Center, Duarte, California.
| | - Javeed Iqbal
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska.
| | - Yan-Yan Liu
- Department of Internal Medicine, Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, Henan, China.
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4
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Hemon P, Renaudineau Y, Debant M, Le Goux N, Mukherjee S, Brooks W, Mignen O. Calcium Signaling: From Normal B Cell Development to Tolerance Breakdown and Autoimmunity. Clin Rev Allergy Immunol 2017; 53:141-165. [DOI: 10.1007/s12016-017-8607-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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5
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Davenport B, Li Y, Heizer JW, Schmitz C, Perraud AL. Signature Channels of Excitability no More: L-Type Channels in Immune Cells. Front Immunol 2015; 6:375. [PMID: 26257741 PMCID: PMC4512153 DOI: 10.3389/fimmu.2015.00375] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/09/2015] [Indexed: 12/16/2022] Open
Abstract
Although the concept of Ca(2+) as a universal messenger is well established, it was assumed that the regulatory mechanisms of Ca(2+)-signaling were divided along the line of electric excitability. Recent advances in molecular biology and genomics have, however, provided evidence that non-excitable cells such as immunocytes also express a wide and diverse pool of ion channels that does not differ as significantly from that of excitable cells as originally assumed. Ion channels and transporters are involved in virtually all aspects of immune response regulation, from cell differentiation and development to activation, and effector functions such as migration, antibody-secretion, phagosomal maturation, or vesicular delivery of bactericidal agents. This comprises TRP channel family members, voltage- and Ca(2+)-gated K(+)- and Na(+)-channels, as well as unexpectedly, components of the CaV1-subfamily of voltage-gated L-type Ca(2+)-channels, originally thought to be signature molecules of excitability. This article provides an overview of recent observations made in the field of CaV1 L-type channel function in the immune context, as well as presents results we obtained studying these channels in B-lymphocytes.
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Affiliation(s)
- Bennett Davenport
- Department of Biomedical Research, National Jewish Health , Denver, CO , USA ; Department of Immunology and Microbiology, University of Colorado Denver , Denver, CO , USA
| | - Yuan Li
- Department of Biomedical Research, National Jewish Health , Denver, CO , USA ; Department of Immunology and Microbiology, University of Colorado Denver , Denver, CO , USA
| | - Justin W Heizer
- Department of Biomedical Research, National Jewish Health , Denver, CO , USA ; Department of Immunology and Microbiology, University of Colorado Denver , Denver, CO , USA
| | - Carsten Schmitz
- Department of Biomedical Research, National Jewish Health , Denver, CO , USA ; Department of Immunology and Microbiology, University of Colorado Denver , Denver, CO , USA
| | - Anne-Laure Perraud
- Department of Biomedical Research, National Jewish Health , Denver, CO , USA ; Department of Immunology and Microbiology, University of Colorado Denver , Denver, CO , USA
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Kleiman E, Salyakina D, De Heusch M, Hoek KL, Llanes JM, Castro I, Wright JA, Clark ES, Dykxhoorn DM, Capobianco E, Takeda A, Renauld JC, Khan WN. Distinct Transcriptomic Features are Associated with Transitional and Mature B-Cell Populations in the Mouse Spleen. Front Immunol 2015; 6:30. [PMID: 25717326 PMCID: PMC4324157 DOI: 10.3389/fimmu.2015.00030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/15/2015] [Indexed: 11/30/2022] Open
Abstract
Splenic transitional B-cells (T1 and T2) are selected to avoid self-reactivity and to safeguard against autoimmunity, then differentiate into mature follicular (FO-I and FO-II) and marginal zone (MZ) subsets. Transcriptomic analysis by RNA-seq of the five B-cell subsets revealed T1 cell signature genes included RAG suggesting a potential for receptor revision. T1 to T2 B-cell differentiation was marked by a switch from Myb to Myc, increased expression of the PI3K adapter DAP10 and MHC class II. FO-II may be an intermediate in FO-I differentiation and may also become MZ B-cells as suggested by principle component analysis. MZ B-cells possessed the most distinct transcriptome including down-regulation of CD45 phosphatase-associated protein (CD45-AP/PTPRC-AP), as well as upregulation of IL-9R and innate molecules TLR3, TLR7, and bactericidal Perforin-2 (MPEG1). Among the endosomal TLRs, stimulation via TLR3 further enhanced Perforin-2 expression exclusively in MZ B-cells. Using gene-deleted and overexpressing transgenic mice we show that IL-9/IL-9R interaction resulted in rapid activation of STAT1, 3, and 5, primarily in MZ B-cells. Importantly, CD45-AP mutant mice had reduced transitional and increased mature MZ and FO B-cells, suggesting that it prevents premature entry of transitional B-cells to the mature B-cell pool or their survival and proliferation. Together, these findings suggest, developmental plasticity among splenic B-cell subsets, potential for receptor revision in peripheral tolerance whereas enhanced metabolism coincides with T2 to mature B-cell differentiation. Further, unique core transcriptional signatures in MZ B-cells may control their innate features.
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Affiliation(s)
- Eden Kleiman
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami , Miami, FL , USA
| | - Daria Salyakina
- Center for Computational Science, University of Miami , Miami, FL , USA
| | - Magali De Heusch
- Ludwig Institute for Cancer Research, Brussels Branch , Brussels , Belgium ; de Duve Institute, Université Catholique de Louvain , Brussels , Belgium
| | - Kristen L Hoek
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine , Nashville, TN , USA
| | - Joan M Llanes
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine , Nashville, TN , USA
| | - Iris Castro
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami , Miami, FL , USA
| | - Jacqueline A Wright
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami , Miami, FL , USA
| | - Emily S Clark
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami , Miami, FL , USA
| | - Derek M Dykxhoorn
- Hussman Institute for Human Genomics, University of Miami , Miami, FL , USA
| | - Enrico Capobianco
- Center for Computational Science, University of Miami , Miami, FL , USA
| | - Akiko Takeda
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis , St. Louis, MO , USA
| | - Jean-Christophe Renauld
- Ludwig Institute for Cancer Research, Brussels Branch , Brussels , Belgium ; de Duve Institute, Université Catholique de Louvain , Brussels , Belgium
| | - Wasif N Khan
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami , Miami, FL , USA
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7
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Gurzell EA, Teague H, Duriancik D, Clinthorne J, Harris M, Shaikh SR, Fenton JI. Marine fish oils are not equivalent with respect to B-cell membrane organization and activation. J Nutr Biochem 2014; 26:369-77. [PMID: 25616447 DOI: 10.1016/j.jnutbio.2014.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 10/29/2014] [Accepted: 11/05/2014] [Indexed: 12/29/2022]
Abstract
We previously reported that docosahexaenoic-acid (DHA)-enriched fish oil (DFO) feeding altered B-cell membrane organization and enhanced B-cell function. The purpose of this study was to evaluate whether menhaden oil (MO) and eicosapentaenoic-acid (EPA)-enriched fish oil (EFO) alters B-cell function/phenotype similarly. Mice were fed control (CON), MO, EFO or DFO diets for 5weeks. We evaluated the fatty acid composition of B-cell phospholipids, membrane microdomain organization, ex vivo B-cell functionality and in vivo B-cell subsets. Red blood cells and B cells were found to be strongly (r>0.85) and significantly (P<.001) correlated for major n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFAs). Compared to CON, MO and DFO resulted in decreased clustering of membrane microdomains, whereas EFO increased clustering. All fish oil treatments had 1.12-1.60 times higher CD40 expression following stimulation; however, we observed 0.86 times lower major histocompatibility complex class II expression and 0.7 times lower interleukin (IL)-6 production from EFO, but 3.25 times higher interferon-γ from MO and 1.5 times higher IL-6 from DFO. By 90min of incubation, MO had 1.11 times higher antigen uptake compared to CON, whereas EFO was 0.86 times lower. All fish oil treatments resulted in decreasingly mature splenic and bone marrow B-cell subsets. We conclude that diets high in n-3 LCPUFAs may elicit similar B-cell phenotypes but different organizational and functional outcomes. More specifically, these data suggest that the EPA and DHA content of a diet influences immunological outcomes, highlighting the importance of understanding how specific n-3 LCPUFAs modulate B-cell development and function.
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Affiliation(s)
- Eric A Gurzell
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824
| | - Heather Teague
- Department of Biochemistry & Molecular Biology, Department of Microbiology & Immunology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834
| | - David Duriancik
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824
| | - Jonathan Clinthorne
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824
| | - Mitchel Harris
- Department of Biochemistry & Molecular Biology, Department of Microbiology & Immunology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834
| | - Saame Raza Shaikh
- Department of Biochemistry & Molecular Biology, Department of Microbiology & Immunology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834
| | - Jenifer I Fenton
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824; College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48824.
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8
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Sharmila S, Christiana I, Kiran P, Reddy MVR, Sankaran K, Kaliraj P. Bacterial lipid modification enhances immunoprophylaxis of filarial abundant larval transcript-2 protein in Mastomys model. Parasite Immunol 2014; 35:201-13. [PMID: 23495791 DOI: 10.1111/pim.12034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/11/2013] [Indexed: 11/29/2022]
Abstract
As in many other parasitic diseases, efficacious vaccine for lymphatic filariasis has been elusive for want of new approaches leaving billions of people either debilitated or at risk. With multiple B- and T-cell epitopes, the abundant larval transcript-2 (ALT-2) of the filarial worm, Brugia malayi, has been shown to be a promising immunoprophylactic target. To enhance its efficacy, it was lipid modified using our recently developed protein engineering tool, which then offered 30% more immunoprotection (49 vs. 79%) in Mastomys coucha model. Sustained high levels of IFN-γ (about 100 times) and high antibody titres (10-fold) elicited by lipid-modified ALT-2, as compared to the native form, indicated the maintenance of Th1/Th2 balance that is impaired in filariasis. Thus, this study provides the basis for developing efficacious vaccines for filariasis and other parasitic diseases by exploiting bacterial lipid modification.
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Affiliation(s)
- S Sharmila
- Centre for Biotechnology, Anna University, Chennai, Tamilnadu, India
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9
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Khan WN, Wright JA, Kleiman E, Boucher JC, Castro I, Clark ES. B-lymphocyte tolerance and effector function in immunity and autoimmunity. Immunol Res 2013; 57:335-53. [DOI: 10.1007/s12026-013-8466-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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10
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Lanzilli G, Traggiai E, Braido F, Garelli V, Folli C, Chiappori A, Riccio AM, Bazurro G, Agazzi A, Magnani A, Canonica GW, Melioli G. Administration of a polyvalent mechanical bacterial lysate to elderly patients with COPD: Effects on circulating T, B and NK cells. Immunol Lett 2012. [PMID: 23206888 DOI: 10.1016/j.imlet.2012.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The modifications of the subsets of circulating lymphocytes were evaluated in a group of patients with COPD undergoing treatment with a polyvalent mechanical bacterial lysate (PMBL), a drug that is able to significantly modify the natural history of these patients. Using multicolor immune-florescence and flow cytometry, T, B subsets and NK cells were extensively studied both in the group of treated patients and in a disease and age matched controls. Despite the age, in treated patients, T and NK cells were significantly increased in numbers of circulating cells, but not in percentages, while B cells remained unmodified. CD3+4+T cells were increased in treated patients, while CD3+CD8T cells were unmodified by the treatment. Activated T cells were increased but Treg, resulted reduced both in percentage than in absolute numbers. Transitional B cells resulted increased (in percentage and in absolute numbers) in their late maturation step (T3), while only early Naïve B cells were increased by the treatment, while other naïve subpopulations were unmodified. Memory B cells were reduced in percentage (but remained unmodified as absolute numbers), while the most immature form of memory B cells was significantly increased. Finally, both switch memory B cells and plasma cells resulted unmodified by the PMBL treatment. These results clearly indicated that the administration of the PMBL, even in elderly patients with COPD, was able to induce a significant immune-stimulation and these results, at cellular level, clearly support the evidence that the mechanism of action of PMBL is strictly related to a direct effect on immune-competent cells.
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Affiliation(s)
- Giulia Lanzilli
- Istituto di Farmacologia Traslazionale, Consiglio Nazionale delle Ricerche (CNR), Via Fosso del Cavaliere, 100, 00133, Roma, Italy
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11
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Andrews SF, Dai X, Ryu BY, Gulick T, Ramachandran B, Rawlings DJ. Developmentally regulated expression of MEF2C limits the response to BCR engagement in transitional B cells. Eur J Immunol 2012; 42:1327-36. [PMID: 22311635 DOI: 10.1002/eji.201142226] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transitional and naïve mature peripheral B cells respond very differently to B-cell receptor (BCR) cross-linking. While transitional B cells undergo apoptosis upon BCR engagement, mature B cells survive and proliferate. This differential response correlates with the capacity of mature, but not transitional B cells to transcribe genes that promote cell survival and proliferation, including those encoding c-Myc and the Bcl-2 family members Bcl-xL and A1. We recently demonstrated that transitional B cells fail to assemble transcriptional machinery at the promoter region of these target genes despite equivalent cytoplasmic signaling and nuclear translocation of key transcription factors including NF-κB and nuclear factor of activated T cells (NFAT). The transcription factor myocyte enhancer factor-2C (MEF2C) is regulated by both calcineurin and mitogen-activated protein kinase signaling pathways, and is essential for proliferation and survival downstream of BCR engagement in mature B cells. In this work, we demonstrate that transitional B cells have intrinsically low levels of MEF2C protein and DNA-binding activity, and that this developmental difference in MEF2C expression is functionally significant. Forced expression of MEF2C in transitional B cells promoted cell survival, proliferation, and upregulation of pro-survival genes. Thus, low MEF2C expression limits transitional B-cell responsiveness to BCR engagement before these cells reach maturity.
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Affiliation(s)
- Sarah F Andrews
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute, Seattle, WA, USA
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12
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Junek S, Engelke M, Schild D, Wienands J. Spatiotemporal resolution of Ca2+signaling events by real time imaging of single B cells. FEBS Lett 2012; 586:1452-8. [DOI: 10.1016/j.febslet.2012.03.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/13/2012] [Accepted: 03/27/2012] [Indexed: 10/28/2022]
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13
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Khan WN. Colonel Bruton's Kinase Defined the Molecular Basis of X-Linked Agammaglobulinemia, the First Primary Immunodeficiency. THE JOURNAL OF IMMUNOLOGY 2012; 188:2933-5. [DOI: 10.4049/jimmunol.1200490] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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14
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Limnander A, Weiss A. Ca-dependent Ras/Erk signaling mediates negative selection of autoreactive B cells. Small GTPases 2011; 2:282-288. [PMID: 22292132 DOI: 10.4161/sgtp.2.5.17794] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/08/2011] [Accepted: 08/18/2011] [Indexed: 12/17/2022] Open
Abstract
Signaling via the Ras/Erk pathway has long been recognized to be critical in lymphocyte development and function, yet the mechanisms that control the distinct functional outputs of this pathway in different cellular contexts remain poorly understood. Our recent results have demonstrated unexpected involvement of Ras/Erk signaling in the sensitization of B cells to apoptosis in order to eliminate autoreactive cells. Increases in cytosolic Ca(2+) are necessary and sufficient to induce activation of this Ras/Erk pathway, and the biochemical events involved in its activation are different from the ones involved in diacylglycerol (DAG)-mediated Ras/Erk activation. Developmental regulation of upstream mediators of these distinct pathways contributes to their predominant activation at different stages of B cell development. These findings have revealed a mechanism by which antigen stimulation can activate distinct Ras/Erk pathways at different developmental stages to mediate appropriate functional outputs that control the selection, development and activation of B cells. Despite these recent findings, however, much remains to be learned about the molecular mechanisms that confer functional specificity to common Ras/Erk signaling modules.
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Affiliation(s)
- Andre Limnander
- Department of Medicine; Howard Hughes Medical Institute; Rosalind Russell Medical Research Center for Arthritis; University of California at San Francisco; San Francisco, CA USA
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15
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STIM1, PKC-δ and RasGRP set a threshold for proapoptotic Erk signaling during B cell development. Nat Immunol 2011; 12:425-33. [PMID: 21441934 PMCID: PMC3623929 DOI: 10.1038/ni.2016] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 03/02/2011] [Indexed: 01/05/2023]
Abstract
Clonal deletion of autoreactive B cells is crucial to prevent autoimmunity, but the signaling mechanisms that regulate this checkpoint remain undefined. Here we characterized a previously unrecognized Ca2+-driven Erk activation pathway, which was pro-apoptotic and biochemically distinct from DAG-induced Erk activation. This pathway required PKCδ and RasGRP proteins and depended on Stim1 concentrations, which control the magnitude of Ca2+ entry. Developmental regulation of these proteins was associated with selective activation of the pathway in B cells prone to negative selection. This checkpoint was impaired in PKCδ-deficient mice, which developed B cell autoimmunity. Conversely, Stim1 overexpression conferred a competitive disadvantage to developing B cells. These findings establish Ca2+-dependent Erk signaling as a critical pro-apoptotic pathway that mediates B cell negative selection.
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16
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Schena F, Gambini C, Gregorio A, Mosconi M, Reverberi D, Gattorno M, Casazza S, Uccelli A, Moretta L, Martini A, Traggiai E. Interferon-γ-dependent inhibition of B cell activation by bone marrow-derived mesenchymal stem cells in a murine model of systemic lupus erythematosus. ACTA ACUST UNITED AC 2010; 62:2776-86. [PMID: 20496367 DOI: 10.1002/art.27560] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Bone marrow-derived mesenchymal stem cells (BM-MSCs) are multipotent cells characterized by immunomodulatory properties and are therefore considered a promising tool for the treatment of immune-mediated diseases. This study was undertaken to assess the influence of murine BM-MSCs on the activation of B cells in (NZB × NZW)F(1) mice as an animal model of systemic lupus erythematosus (SLE). METHODS We evaluated the in vitro effects of BM-MSCs on the proliferation and differentiation to plasma cells of splenic mature B cell subsets, namely follicular and marginal zone B cells isolated from (NZB × NZW)F(1) mice. Lupus mice were also treated with BM-MSCs, and serum autoantibodies, proteinuria, histologic changes in the kidney, and survival rates were monitored. RESULTS BM-MSCs inhibited antigen-dependent proliferation and differentiation to plasma cells of follicular and marginal zone B cells in vitro. This inhibitory effect was dependent on interferon-γ (IFNγ) and was mediated by cell-to-cell contact, involving the programmed death 1 (PD-1)/PD ligand pathway. In vivo treatment with BM-MSCs did not affect the levels of anti-double-stranded DNA antibodies or proteinuria. However, a reduction in glomerular immune complex deposition, lymphocytic infiltration, and glomerular proliferation was observed. CONCLUSION Our findings indicate that BM-MSCs affect B cell receptor-dependent activation of both follicular and marginal zone B cells from lupus mice. This inhibitory effect is IFNγ-dependent and cell contact-dependent. MSCs in vivo do not affect the production of autoantibodies, the level of proteinuria, or the mortality rates. Nonetheless, the significant improvement in histologic findings in the kidney supports the potential role of MSCs in the prevention of glomerular damage.
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Mackay F, Figgett WA, Saulep D, Lepage M, Hibbs ML. B-cell stage and context-dependent requirements for survival signals from BAFF and the B-cell receptor. Immunol Rev 2010; 237:205-25. [DOI: 10.1111/j.1600-065x.2010.00944.x] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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18
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Abstract
The growth factor receptor-bound protein 2 (Grb2) is a ubiquitously expressed and evolutionary conserved adapter protein possessing a plethora of described interaction partners for the regulation of signal transduction. In B lymphocytes, the Grb2-mediated scaffolding function controls the assembly and subcellular targeting of activating as well as inhibitory signalosomes in response to ligation of the antigen receptor. Also, integration of simultaneous signals from B-cell coreceptors that amplify or attenuate antigen receptor signal output relies on Grb2. Hence, Grb2 is an essential signal integrator. The key question remains, however, of how pathway specificity can be maintained during signal homeostasis critically required for the balance between immune cell activation and tolerance induction. Here, we summarize the molecular network of Grb2 in B cells and introduce a proteomic approach to elucidate the interactome of Grb2 in vivo.
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Affiliation(s)
- Konstantin Neumann
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
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19
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Khan WN. B cell receptor and BAFF receptor signaling regulation of B cell homeostasis. THE JOURNAL OF IMMUNOLOGY 2009; 183:3561-7. [PMID: 19726767 DOI: 10.4049/jimmunol.0800933] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
B lymphocyte homeostasis depends on tonic and induced BCR signaling and receptors sensitive to trophic factors, such as B cell-activating factor receptor (BAFF-R or BR3) during development and maintenance. This review will discuss growing evidence suggesting that the signaling mechanisms that maintain B cell survival and metabolic fitness during selection at transitional stages and survival after maturation rely on cross-talk between BCR and BR3 signaling. Recent findings have also begun to unravel the molecular mechanisms underlying this crosstalk. In this review I also propose a model for regulating the amplitude of BCR signaling by a signal amplification loop downstream of the BCR involving Btk and NF-kappaB that may facilitate BCR-dependent B cell survival as well as its functional coupling to BR3 for the growth and survival of B lymphocytes.
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Affiliation(s)
- Wasif N Khan
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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20
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B-cell reconstitution and BAFF after alemtuzumab (Campath-1H) treatment of multiple sclerosis. J Clin Immunol 2009; 30:99-105. [PMID: 19763798 DOI: 10.1007/s10875-009-9327-3] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 08/20/2009] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Treatment with alemtuzumab is highly effective in relapsing-remitting multiple sclerosis; however, 30% of patients develop autoimmunity. Alemtuzumab (previously called Campath 1-H) induces a prolonged T-cell lymphopenia with memory cells dominating the reconstituting T-cell pool for at least 3 months. RESULTS Here we show that B-cell recovery is rapid, returning to baseline by 3 months and rising to 165% of baseline by 12 months after treatment. Immature transitional 1 B cells are the predominant cell type 1 month after treatment. This coincides with a surge in serum B-cell activating factor (BAFF), which remains elevated by 33% for at least 12 months after alemtuzumab. BAFF is critical for transition to the mature naive B-cell phenotype, which dominates from 3 months after alemtuzumab. Differentiation to memory B cells is slow so there are radical and prolonged alterations to the B-cell pool after alemtuzumab.
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Castro I, Wright JA, Damdinsuren B, Hoek KL, Carlesso G, Shinners NP, Gerstein RM, Woodland RT, Sen R, Khan WN. B cell receptor-mediated sustained c-Rel activation facilitates late transitional B cell survival through control of B cell activating factor receptor and NF-kappaB2. THE JOURNAL OF IMMUNOLOGY 2009; 182:7729-37. [PMID: 19494297 DOI: 10.4049/jimmunol.0803281] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Signaling from the BCR and B cell activating factor receptor (BAFF-R or BR3) differentially regulates apoptosis within early transitional (T1) and late transitional (T2; CD21(int)-T2) B cells during selection processes to generate mature B lymphocytes. However, molecular mechanisms underlying the differential sensitivity of transitional B cells to apoptosis remain unclear. In this study, we demonstrate that BCR signaling induced more long-term c-Rel activation in T2 and mature than in T1 B cells leading to increased expression of anti-apoptotic genes as well as prosurvival BAFF-R and its downstream substrate p100 (NF-kappaB2). Sustained c-Rel activation required de novo c-Rel gene transcription and translation via Btk-dependent mechanisms. Like T1 cells, mature B cells from Btk- and c-Rel-deficient mice also failed to activate these genes. These findings suggest that the gain of survival potential within transitional B cells is dependent on the ability to produce a long-term c-Rel response, which plays a critical role in T2 B cell survival and differentiation in vivo by inducing anti-apoptotic genes, BAFF-R and NF-kappaB2, an essential component for BAFF-R survival signaling. Thus, acquisition of resistance to apoptosis during transitional B cell maturation is achieved by integration of BCR and BAFF-R signals.
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Affiliation(s)
- Iris Castro
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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22
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Gross AJ, Lyandres JR, Panigrahi AK, Prak ETL, DeFranco AL. Developmental acquisition of the Lyn-CD22-SHP-1 inhibitory pathway promotes B cell tolerance. THE JOURNAL OF IMMUNOLOGY 2009; 182:5382-92. [PMID: 19380785 DOI: 10.4049/jimmunol.0803941] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
To better understand whether autoimmunity in Lyn-deficient mice arises from compromised central or peripheral B cell tolerance, we examined BCR signaling properties of wild-type and Lyn-deficient B cells at different stages of development. Wild-type mature follicular B cells were less sensitive to BCR stimulation than were immature transitional stage 1 B cells with regard to BCR-induced calcium elevation and ERK MAPK activation. In the absence of Lyn, mature B cell signaling was greatly enhanced, whereas immature B cell signaling was minimally affected. Correspondingly, Lyn deficiency substantially enhanced the sensitivity of mature B cells to activation via the BCR, but minimally affected events associated with tolerance induction at the immature stage. The effects of CD22 deficiency on BCR signaling were very similar in B cells at different stages of maturation. These results indicate that the Lyn-CD22-Src homology region 2 domain-containing phosphatase-1 inhibitory pathway largely becomes operational as B cell mature, and sets a threshold for activation that appears to be critical for the maintenance of tolerance in the B cell compartment.
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Affiliation(s)
- Andrew J Gross
- Department of Medicine, University of California, San Francisco, CA 94143, USA
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23
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Miller AT, Beisner DR, Liu D, Cooke MP. Inositol 1,4,5-trisphosphate 3-kinase B is a negative regulator of BCR signaling that controls B cell selection and tolerance induction. THE JOURNAL OF IMMUNOLOGY 2009; 182:4696-704. [PMID: 19342645 DOI: 10.4049/jimmunol.0802850] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Inositol 1,4,5-trisphosphate 3-kinase B (or Itpkb) converts inositol 1,4,5-trisphosphate to inositol 1,3,4,5-tetrakisphosphate upon Ag receptor activation and controls the fate and function of lymphocytes. To determine the role of Itpkb in B cell tolerance, Itpkb(-/-) mice were crossed to transgenic mice that express a BCR specific for hen egg lysozyme (IgHEL). B cells from Itpkb(-/-) IgHEL mice possess an anergic phenotype, hypoproliferate in response to cognate Ag, and yet they exhibit enhanced Ag-induced calcium signaling. In IgHEL transgenic mice that also express soluble HEL, lack of Itpkb converts anergy induction to deletion. These data establish Itpkb as a negative regulator of BCR signaling that controls the fate of developing B cells and tolerance induction.
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Affiliation(s)
- Andrew T Miller
- The Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
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24
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Andrews SF, Rawlings DJ. Transitional B cells exhibit a B cell receptor-specific nuclear defect in gene transcription. THE JOURNAL OF IMMUNOLOGY 2009; 182:2868-78. [PMID: 19234182 DOI: 10.4049/jimmunol.0802368] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The signaling programs that enforce negative selection in early transitional (T1) B cells in response to BCR engagement remain poorly defined. We conducted a comprehensive comparison of BCR signaling in T1 vs follicular mature splenic B cells. T1, in contrast to follicular mature B cells, failed to express key NF-kappaB target genes in response to BCR engagement and exhibited a striking defect in assembly of an active transcriptional complex at the promoter of the survival and proliferative genes A1 and c-Myc. Surprisingly, and contrary to previous models, classical protein kinase C and IkappaB kinase activation, NF-kappaB nuclear translocation and DNA binding were intact in T1 B cells. Furthermore, despite a marked reduction in NFAT1 expression, differential NFAT or AP-1 activation cannot explain this transcriptional defect. Our combined findings demonstrate that T1 B cells are programmed for signal- and stage-specific "nuclear nonresponsiveness" upon encounter with self-Ags.
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Affiliation(s)
- Sarah F Andrews
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195, USA
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25
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Signalling of the BCR is regulated by a lipid rafts-localised transcription factor, Bright. EMBO J 2009; 28:711-24. [PMID: 19214191 DOI: 10.1038/emboj.2009.20] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 01/09/2009] [Indexed: 02/06/2023] Open
Abstract
Regulation of BCR signalling strength is crucial for B-cell development and function. Bright is a B-cell-restricted factor that complexes with Bruton's tyrosine kinase (Btk) and its substrate, transcription initiation factor-I (TFII-I), to activate immunoglobulin heavy chain gene transcription in the nucleus. Here we show that a palmitoylated pool of Bright is diverted to lipid rafts of resting B cells where it associates with signalosome components. After BCR ligation, Bright transiently interacts with sumoylation enzymes, blocks calcium flux and phosphorylation of Btk and TFII-I and is then discharged from lipid rafts as a Sumo-I-modified form. The resulting lipid raft concentration of Bright contributes to the signalling threshold of B cells, as their sensitivity to BCR stimulation decreases as the levels of Bright increase. Bright regulates signalling independent of its role in IgH transcription, as shown by specific dominant-negative titration of rafts-specific forms. This study identifies a BCR tuning mechanism in lipid rafts that is regulated by differential post-translational modification of a transcription factor with implications for B-cell tolerance and autoimmunity.
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26
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Cao S, Carlesso G, Osipovich AB, Llanes J, Lin Q, Hoek KL, Khan WN, Ruley HE. Subunit 1 of the prefoldin chaperone complex is required for lymphocyte development and function. THE JOURNAL OF IMMUNOLOGY 2008; 181:476-84. [PMID: 18566413 DOI: 10.4049/jimmunol.181.1.476] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prefoldin is a hexameric chaperone that facilitates posttranslational folding of actins and other cytoskeletal proteins by the Tcp1-containing ring complex chaperonin, TriC. The present study characterized mice with a null mutation in Pfdn1, which encodes the first subunit of the Prefoldin complex. Pfdn1-deficient mice displayed phenotypes characteristic of defects in cytoskeletal function, including manifestations of ciliary dyskinesia, neuronal loss, and defects in B and T cell development and function. B and T cell maturation was markedly impaired at relatively early stages, namely at the transitions from pre-pro-B to pre-B cells in the bone marrow and from CD4-CD8- double-negative to CD4+CD8+ double-positive T cells in the thymus. In addition, mature B and T lymphocytes displayed cell activation defects upon Ag receptor cross-linking accompanied by impaired Ag receptor capping in B cells. These phenotypes illustrate the importance of cytoskeletal function in immune cell development and activation.
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Affiliation(s)
- Shang Cao
- Department of Microbiology and Immunology, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
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27
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Zheng H, Nam JH, Nguen YH, Kang TM, Kim TJ, Earm YE, Kim SJ. Arachidonic acid-induced activation of large-conductance potassium channels and membrane hyperpolarization in mouse B cells. Pflugers Arch 2008; 456:867-81. [PMID: 18214524 DOI: 10.1007/s00424-008-0445-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 12/13/2007] [Accepted: 01/02/2008] [Indexed: 12/31/2022]
Abstract
Lymphocytes express voltage-gated (Kv) and Ca(2+)-activated (IKCa1) K(+) channels. Recently, we found that WEHI-231, an immature B cell line, expresses voltage-independent K(+) channels called large-conductance background K( + ) channels (LK(bg)). Arachidonic acid (AA) has attracted attention because of its potential regulatory roles in the apoptosis of immature B cells. To elucidate the functional targets of AA, we investigated the effects of AA on membrane currents, voltages, and cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) of WEHI-231 and Bal-17 cells that represent immature and mature mouse B cells, respectively. In whole-cell patch clamp, both Kv and IKCa1 were inhibited by AA. On the other hand, AA activated LK(bg) current and non-selective cationic (NSC) current in WEHI-231 while only NSC current in Bal-17. Inside-out patch clamp study showed that AA directly activates LK(bg). AA induced hyperpolarization of WEHI-231 and depolarization of Bal-17 cells, respectively. The selective functional expression of LK(bg) and their activation by AA were also confirmed in the immature B cells (B220(+)/AA4.1(+)) freshly isolated from mouse spleen. In fura-2 spectrofluorimetry, AA induced persistent increase in [Ca(2+)](c) of WEHI-231 cells, which was attenuated by KCl-induced depolarization. In Bal-17 cell, however, AA induced only a transient increase of [Ca(2+)](c). In summary, the novel type of background K(+) channels (LK(bg)) in immature B cells is strongly activated while the other K(+) channels (Kv and IKCa1) commonly expressed in lymphocytes are inhibited by AA. The hyperpolarization and augmentation of Ca(2+) influx by LK(bg) activation might play a role in the response of immature B cells to AA.
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Affiliation(s)
- Haifeng Zheng
- Department of Physiology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul, 110-799, South Korea
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28
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Conformational plasticity and navigation of signaling proteins in antigen-activated B lymphocytes. Adv Immunol 2008; 97:251-81. [PMID: 18501772 DOI: 10.1016/s0065-2776(08)00005-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Over the past two decades our view of the B cell antigen receptor (BCR) has fundamentally changed. Being initially regarded as a mute antibody orphan of the B cell surface, the BCR turned out to be a complex multimolecular machine monitoring almost all stages of B cell development, selection, and activation through a plethora of ubiquitously and cell-type-specific effector proteins. A comprehensive understanding of the many BCR signaling facets is still out but a few common biochemical principles outlined in this review operate at the level of receptor activation and orchestrate specific wiring of intracellular transducer cascades. First, initiation and processing of antigen-induced signal transduction relies on transient conformational changes in the signaling proteins to trigger their physical interaction with downstream elements. Second, this dynamic assembly of signalosomes occurs at distinct subcellular locations, most prominently the plasma membrane, which requires dynamic relocalization of one or more of the engaged molecules. For both, precise complex formation and efficient subcellular targeting, B cell signaling components are equipped with a variety of protein interaction domains. Here we provide an overview on how these simple rules are applied by a limited number of transmembrane and cytosolic proteins to convert BCR ligation into Ca(2+) mobilization and Ras activation in an adjustable manner.
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29
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Antony P, Hoek K, Sarmah B, Khan WN. Micro-scale flow cytometry-based and biochemical analysis of lipid signaling in primary B cell subpopulations. Biol Proced Online 2007; 9:73-83. [PMID: 18385809 PMCID: PMC2275047 DOI: 10.1251/bpo135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 10/25/2007] [Accepted: 12/09/2007] [Indexed: 11/23/2022] Open
Abstract
B cell subpopulations in the spleen have been extensively characterized phenotypically; however, biochemical properties of these cell populations following B cell antigen receptor engagement have not been fully determined due to technical difficulties and limiting cell numbers. We therefore employed mini-scale protocols to assess lipid signaling, particularly that of diacylglycerol and inositol trisphosphate, with as few as 0.5x10(6) purified early (T1) and late (T2) transitional B cells. Additionally, utilizing flow cytometric techniques, we determined levels of phosphatidylinositol bisphosphate and calcium mobilization in T1 and T2 cells, as well as mature follicular and marginal zone B cells using less than 1x10(6 )primary B cells. Thus, these biochemical and flow cytometric methodologies can be used to analyse signal-induced changes in phosphatidylinositol bisphosphate levels, diacylglycerol and inositol triphosphate production and calcium in each B cell population.
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Wang H, Feng J, Qi CF, Li Z, Morse HC, Clarke SH. Transitional B Cells Lose Their Ability to Receptor Edit but Retain Their Potential for Positive and Negative Selection. THE JOURNAL OF IMMUNOLOGY 2007; 179:7544-52. [DOI: 10.4049/jimmunol.179.11.7544] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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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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32
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Stork B, Neumann K, Goldbeck I, Alers S, Kähne T, Naumann M, Engelke M, Wienands J. Subcellular localization of Grb2 by the adaptor protein Dok-3 restricts the intensity of Ca2+ signaling in B cells. EMBO J 2007; 26:1140-9. [PMID: 17290227 PMCID: PMC1852829 DOI: 10.1038/sj.emboj.7601557] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 12/19/2006] [Indexed: 01/19/2023] Open
Abstract
Spatial and temporal modulation of intracellular Ca2+ fluxes controls the cellular response of B lymphocytes to antigen stimulation. Herein, we identify the hematopoietic adaptor protein Dok-3 (downstream of kinase-3) as a key component of negative feedback regulation in Ca2+ signaling from the B-cell antigen receptor. Dok-3 localizes at the inner leaflet of the plasma membrane and is a major substrate for activated Src family kinase Lyn. Phosphorylated Dok-3 inhibits antigen receptor-induced Ca2+ elevation by recruiting cytosolic Grb2, which acts at this location as a negative regulator of Bruton's tyrosine kinase. This leads to diminished activation of phospholipase C-gamma2 and reduced production of soluble inositol trisphosphate. Hence, the Dok-3/Grb2 module is a membrane-associated signaling organizer, which orchestrates the interaction efficiency of Ca2+-mobilizing enzymes.
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Affiliation(s)
- Björn Stork
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
| | - Konstantin Neumann
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
| | - Ingo Goldbeck
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
| | - Sebastian Alers
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany
| | - Michael Engelke
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
| | - Jürgen Wienands
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Göttingen, Germany
- Institute of Cellular and Molecular Immunology, Georg August University of Göttingen, Humboldtallee 34, 37073 Göttingen, Germany. Tel.: +49 (0)551 39 5812; Fax: +49 (0)551 39 5843, E-mail:
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