1
|
Graham A. Modulation of the Cellular microRNA Landscape: Contribution to the Protective Effects of High-Density Lipoproteins (HDL). BIOLOGY 2023; 12:1232. [PMID: 37759631 PMCID: PMC10526091 DOI: 10.3390/biology12091232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023]
Abstract
High-density lipoproteins (HDL) play an established role in protecting against cellular dysfunction in a variety of different disease contexts; however, harnessing this therapeutic potential has proved challenging due to the heterogeneous and relative instability of this lipoprotein and its variable cargo molecules. The purpose of this study is to examine the contribution of microRNA (miRNA; miR) sequences, either delivered directly or modulated endogenously, to these protective functions. This narrative review introduces the complex cargo carried by HDL, the protective functions associated with this lipoprotein, and the factors governing biogenesis, export and the uptake of microRNA. The possible mechanisms by which HDL can modulate the cellular miRNA landscape are considered, and the impact of key sequences modified by HDL is explored in diseases such as inflammation and immunity, wound healing, angiogenesis, dyslipidaemia, atherosclerosis and coronary heart disease, potentially offering new routes for therapeutic intervention.
Collapse
Affiliation(s)
- Annette Graham
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, UK
| |
Collapse
|
2
|
Oh S, Mao X, Manfredo-Vieira S, Lee J, Patel D, Choi EJ, Alvarado A, Cottman-Thomas E, Maseda D, Tsao PY, Ellebrecht CT, Khella SL, Richman DP, O'Connor KC, Herzberg U, Binder GK, Milone MC, Basu S, Payne AS. Precision targeting of autoantigen-specific B cells in muscle-specific tyrosine kinase myasthenia gravis with chimeric autoantibody receptor T cells. Nat Biotechnol 2023; 41:1229-1238. [PMID: 36658341 PMCID: PMC10354218 DOI: 10.1038/s41587-022-01637-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 12/08/2022] [Indexed: 01/21/2023]
Abstract
Muscle-specific tyrosine kinase myasthenia gravis (MuSK MG) is an autoimmune disease that causes life-threatening muscle weakness due to anti-MuSK autoantibodies that disrupt neuromuscular junction signaling. To avoid chronic immunosuppression from current therapies, we engineered T cells to express a MuSK chimeric autoantibody receptor with CD137-CD3ζ signaling domains (MuSK-CAART) for precision targeting of B cells expressing anti-MuSK autoantibodies. MuSK-CAART demonstrated similar efficacy as anti-CD19 chimeric antigen receptor T cells for depletion of anti-MuSK B cells and retained cytolytic activity in the presence of soluble anti-MuSK antibodies. In an experimental autoimmune MG mouse model, MuSK-CAART reduced anti-MuSK IgG without decreasing B cells or total IgG levels, reflecting MuSK-specific B cell depletion. Specific off-target interactions of MuSK-CAART were not identified in vivo, in primary human cell screens or by high-throughput human membrane proteome array. These data contributed to an investigational new drug application and phase 1 clinical study design for MuSK-CAART for the treatment of MuSK autoantibody-positive MG.
Collapse
Affiliation(s)
- Sangwook Oh
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xuming Mao
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Silvio Manfredo-Vieira
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Eun Jung Choi
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Damian Maseda
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Patricia Y Tsao
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christoph T Ellebrecht
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sami L Khella
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David P Richman
- Department of Neurology, University of California - Davis, Davis, CA, USA
| | - Kevin C O'Connor
- Departments of Neurology and Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | | | | | - Michael C Milone
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Aimee S Payne
- Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
3
|
Britt RD, Porter N, Grayson MH, Gowdy KM, Ballinger M, Wada K, Kim HY, Guerau-de-Arellano M. Sterols and immune mechanisms in asthma. J Allergy Clin Immunol 2023; 151:47-59. [PMID: 37138729 PMCID: PMC10151016 DOI: 10.1016/j.jaci.2022.09.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The field of sterol and oxysterol biology in lung disease has recently gained attention, revealing a unique need for sterol uptake and metabolism in the lung. The presence of cholesterol transport, biosynthesis, and sterol/oxysterol-mediated signaling in immune cells suggests a role in immune regulation. In support of this idea, statin drugs that inhibit the cholesterol biosynthesis rate-limiting step enzyme, hydroxymethyl glutaryl coenzyme A reductase, show immunomodulatory activity in several models of inflammation. Studies in human asthma reveal contradicting results, whereas promising retrospective studies suggest benefits of statins in severe asthma. Here, we provide a timely review by discussing the role of sterols in immune responses in asthma, analytical tools to evaluate the role of sterols in disease, and potential mechanistic pathways and targets relevant to asthma. Our review reveals the importance of sterols in immune processes and highlights the need for further research to solve critical gaps in the field.
Collapse
Affiliation(s)
- Rodney D. Britt
- Center for Perinatal Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus
- Department of Pediatrics, The Ohio State University, Columbus
| | - Ned Porter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville
| | - Mitchell H. Grayson
- Center for Clinical and Translational Research, The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus
- Division of Allergy and Immunology, Department of Pediatrics, Nationwide Children’s Hospital, Columbus
| | - Kymberly M. Gowdy
- Division of Pulmonary, Critical Care and Sleep Medicine, College of Medicine, Wexner Medical Center, Columbus
| | - Megan Ballinger
- Division of Pulmonary, Critical Care and Sleep Medicine, College of Medicine, Wexner Medical Center, Columbus
| | - Kara Wada
- Department of Otolaryngology, Wexner Medical Center, Columbus
| | - Hye-Young Kim
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville
| | - Mireia Guerau-de-Arellano
- School of Health and Rehabilitation Sciences, Division of Medical Laboratory Science, College of Medicine, Wexner Medical Center, Columbus
- Institute for Behavioral Medicine Research, The Ohio State University, Columbus
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus
- Department of Neuroscience, The Ohio State University, Columbus
| |
Collapse
|
4
|
The immunopathology of B lymphocytes during stroke-induced injury and repair. Semin Immunopathol 2022:10.1007/s00281-022-00971-3. [PMID: 36446955 PMCID: PMC9708141 DOI: 10.1007/s00281-022-00971-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/28/2022] [Indexed: 11/30/2022]
Abstract
B cells, also known as B lymphocytes or lymphoid lineage cells, are a historically understudied cell population with regard to brain-related injuries and diseases. However, an increasing number of publications have begun to elucidate the different phenotypes and roles B cells can undertake during central nervous system (CNS) pathology, including following ischemic and hemorrhagic stroke. B cell phenotype is intrinsically linked to function following stroke, as they may be beneficial or detrimental depending on the subset, timing, and microenvironment. Factors such as age, sex, and presence of co-morbidity also influence the behavior of post-stroke B cells. The following review will briefly describe B cells from origination to senescence, explore B cell function by integrating decades of stroke research, differentiate between the known B cell subtypes and their respective activity, discuss some of the physiological influences on B cells as well as the influence of B cells on certain physiological functions, and highlight the differences between B cells in healthy and disease states with particular emphasis in the context of ischemic stroke.
Collapse
|
5
|
McShane AN, Malinova D. The Ins and Outs of Antigen Uptake in B cells. Front Immunol 2022; 13:892169. [PMID: 35572544 PMCID: PMC9097226 DOI: 10.3389/fimmu.2022.892169] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
A review of our current knowledge of B cell antigen uptake mechanisms, the relevance of these processes to pathology, and outstanding questions in the field. Specific antigens induce B cell activation through the B cell receptor (BCR) which initiates downstream signaling and undergoes endocytosis. While extensive research has shed light on the signaling pathways in health and disease, the endocytic mechanisms remain largely uncharacterized. Given the importance of BCR-antigen internalization for antigen presentation in initiating adaptive immune responses and its role in autoimmunity and malignancy, understanding the molecular mechanisms represents critical, and largely untapped, potential therapeutics. In this review, we discuss recent advancements in our understanding of BCR endocytic mechanisms and the role of the actin cytoskeleton and post-translational modifications in regulating BCR uptake. We discuss dysregulated BCR endocytosis in the context of B cell malignancies and autoimmune disorders. Finally, we pose several outstanding mechanistic questions which will critically advance our understanding of the coordination between BCR endocytosis and B cell activation.
Collapse
Affiliation(s)
- Adam Nathan McShane
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Dessislava Malinova
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| |
Collapse
|
6
|
Enterina JR, Sarkar S, Streith L, Jung J, Arlian BM, Meyer SJ, Takematsu H, Xiao C, Baldwin TA, Nitschke L, Shlomchick MJ, Paulson JC, Macauley MS. Coordinated changes in glycosylation regulate the germinal center through CD22. Cell Rep 2022; 38:110512. [PMID: 35294874 PMCID: PMC9018098 DOI: 10.1016/j.celrep.2022.110512] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 01/19/2022] [Accepted: 02/16/2022] [Indexed: 12/18/2022] Open
Abstract
Germinal centers (GCs) are essential for antibody affinity maturation. GC B cells have a unique repertoire of cell surface glycans compared with naive B cells, yet functional roles for changes in glycosylation in the GC have yet to be ascribed. Detection of GCs by the antibody GL7 reflects a downregulation in ligands for CD22, an inhibitory co-receptor of the B cell receptor. To test a functional role for downregulation of CD22 ligands in the GC, we generate a mouse model that maintains CD22 ligands on GC B cells. With this model, we demonstrate that glycan remodeling plays a critical role in the maintenance of B cells in the GC. Sustained expression of CD22 ligands induces higher levels of apoptosis in GC B cells, reduces memory B cell and plasma cell output, and delays affinity maturation of antibodies. These defects are CD22 dependent, demonstrating that downregulation of CD22 ligands on B cells plays a critical function in the GC.
Collapse
Affiliation(s)
- Jhon R Enterina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Susmita Sarkar
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Laura Streith
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Britni M Arlian
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sarah J Meyer
- Division of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
| | - Hiromu Takematsu
- Faculty of Medical Technology, Fujita Health University, Aichi 470-1192, Japan
| | - Changchun Xiao
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Troy A Baldwin
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Lars Nitschke
- Division of Genetics, Department of Biology, University of Erlangen, 91058 Erlangen, Germany
| | - Mark J Shlomchick
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - James C Paulson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Matthew S Macauley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
| |
Collapse
|
7
|
Tanaka S, Ise W, Baba Y, Kurosaki T. Silencing and activating anergic B cells. Immunol Rev 2021; 307:43-52. [PMID: 34908172 DOI: 10.1111/imr.13053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 11/30/2021] [Indexed: 02/06/2023]
Abstract
Despite the existence of central tolerance mechanisms, including clonal deletion and receptor editing to eliminate self-reactive B cells, moderately self-reactive cells still survive in the periphery (about 20% of peripheral B cells). These cells normally exist in a functionally silenced state called anergy; thus, anergy has been thought to contribute to tolerance by active-silencing of potentially dangerous B cells. However, a positive rationale for the existence of these anergic B cells has recently been suggested by discoveries that broadly neutralizing antibodies for HIV and influenza virus possess poly- and/or auto-reactivity. Given the conundrum of generating inherent holes in the immune repertoire, retaining weakly self-reactive BCRs on anergic B cells could allow these antibodies to serve as an effective defense against pathogens, particularly in the case of pathogens that mimic forbidden self-epitopes to evade the host immune system. Thus, anergic B cells should be brought into a silenced or activated state, depending on their contexts. Here, we review recent progress in our understanding of how the anergic B cell state is controlled in B cell-intrinsic and B cell-extrinsic ways.
Collapse
Affiliation(s)
- Shinya Tanaka
- Division of Immunology and Genome Biology, Department of Molecular Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Wataru Ise
- Team of Host Defense, Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan.,Laboratory of Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Yoshihiro Baba
- Division of Immunology and Genome Biology, Department of Molecular Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Tomohiro Kurosaki
- Laboratory of Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Division of Microbiology and Immunology, Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan.,Laboratory of Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan
| |
Collapse
|
8
|
Fernandes das Neves M, Batuca JR, Delgado Alves J. The role of high-density lipoprotein in the regulation of the immune response: implications for atherosclerosis and autoimmunity. Immunology 2021; 164:231-241. [PMID: 33934336 PMCID: PMC8442240 DOI: 10.1111/imm.13348] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/29/2021] [Accepted: 04/16/2021] [Indexed: 12/21/2022] Open
Abstract
Inflammation and immune dysfunction have been increasingly recognized as crucial mechanisms in atherogenesis. Modifications in cell lipid metabolism, plasma dyslipidaemia and particularly low high-density lipoprotein (HDL) levels occur both in atherosclerosis and in autoimmune rheumatic diseases (which are strongly associated with an increased risk of atherosclerosis), suggesting the presence of a crucial link. HDL, the plasma lipoprotein responsible for reverse cholesterol transport, is known for its several protective effects in the context of atherosclerosis. Among these, HDL immunomodulatory effects are possibly the less understood. Through the efflux of cholesterol from plasma cell membranes with the consequent disruption of lipid rafts and the interaction with the cholesterol transporters present in the plasma membrane, HDL affects both the innate and adaptive immune responses. Animal and human studies have demonstrated a predominance of HDL anti-inflammatory effects, despite some pro-inflammatory actions having also been reported. The HDL role on the modulation of the immune response is further suggested by the detection of low levels together with a dysfunctional HDL in patients with autoimmune diseases. Here, we review the current knowledge of the immune mechanisms of atherosclerosis and the modulatory effects HDL may have on them.
Collapse
Affiliation(s)
- Marisa Fernandes das Neves
- Center of the Study of Chronic DiseasesNew University of LisbonLisbonPortugal
- Medicine 4 DepartmentFernando Fonseca HospitalAmadoraPortugal
| | - Joana R. Batuca
- Center of the Study of Chronic DiseasesNew University of LisbonLisbonPortugal
| | - José Delgado Alves
- Center of the Study of Chronic DiseasesNew University of LisbonLisbonPortugal
- Medicine 4 DepartmentFernando Fonseca HospitalAmadoraPortugal
| |
Collapse
|
9
|
Zhang T, Hu W, Chen W. Plasma Membrane Integrates Biophysical and Biochemical Regulation to Trigger Immune Receptor Functions. Front Immunol 2021; 12:613185. [PMID: 33679752 PMCID: PMC7933204 DOI: 10.3389/fimmu.2021.613185] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/06/2021] [Indexed: 11/23/2022] Open
Abstract
Plasma membrane provides a biophysical and biochemical platform for immune cells to trigger signaling cascades and immune responses against attacks from foreign pathogens or tumor cells. Mounting evidence suggests that the biophysical-chemical properties of this platform, including complex compositions of lipids and cholesterols, membrane tension, and electrical potential, could cooperatively regulate the immune receptor functions. However, the molecular mechanism is still unclear because of the tremendous compositional complexity and spatio-temporal dynamics of the plasma membrane. Here, we review the recent significant progress of dynamical regulation of plasma membrane on immune receptors, including T cell receptor, B cell receptor, Fc receptor, and other important immune receptors, to proceed mechano-chemical sensing and transmembrane signal transduction. We also discuss how biophysical-chemical cues couple together to dynamically tune the receptor's structural conformation or orientation, distribution, and organization, thereby possibly impacting their in-situ ligand binding and related signal transduction. Moreover, we propose that electrical potential could potentially induce the biophysical-chemical coupling change, such as lipid distribution and membrane tension, to inevitably regulate immune receptor activation.
Collapse
Affiliation(s)
- Tongtong Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The Center for Integrated Oncology and Precision Medicine, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Hu
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Chen
- Department of Cell Biology and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory for Biomedical Engineering of Ministry of Education, State Key Laboratory for Modern Optical Instrumentation, College of Biomedical Engineering and Instrument Science, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, China
| |
Collapse
|
10
|
Wu BR, Eltahla AA, Keoshkerian E, Walker MR, Underwood A, Brasher NA, Agapiou D, Lloyd AR, Bull RA. A method for detecting hepatitis C envelope specific memory B cells from multiple genotypes using cocktail E2 tetramers. J Immunol Methods 2019; 472:65-74. [PMID: 31226262 DOI: 10.1016/j.jim.2019.06.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/13/2019] [Accepted: 06/17/2019] [Indexed: 01/16/2023]
Abstract
Hepatitis C (HCV) is a rapidly mutating RNA virus, with a strong propensity to cause chronic infection and progressive liver disease. Recent evidence has shown that early appearance of neutralizing antibodies in primary infection is associated with clearance. Little is known about the characteristics of HCV-specific B cells and their correlation with outcomes in primary infection, as there is a lack of sensitive tools for HCV-specific B cells which are present at very low frequency. We describe the development and optimisation of tetramer staining for flow cytometric detection of HCV-specific B cells using a cocktail of two recombinant HCV Envelope-2 (rE2) glycoproteins (from genotype 1a and 3a; Gt1a and Gt3a) and streptavidin dyes. The optimal weight to weight (w/w) ratio of streptavidin-phycoerythrin (PE) and rE2 proteins were determined for sensitive detection using HCV E2-specific hybridoma cell lines and peripheral blood mononuclear cells (PBMC) from HCV-infected individuals. In a cross-sectional set of PBMC samples collected from 33 subjects with either chronic infection or previous clearance, HCV E2-specific B cells (CD19+CD20+CD10-IgD-tetramer+) were detected in 29 subjects (87.8%), with a mean frequency of 0.45% (0.012-2.20%). To validate the specificity of tetramer staining, 367 HCV E2-specific B cells were single cell sorted from 9 PBMC samples before monoclonal antibodies (mAbs) were synthesised, with 87.5% being reactive to E2 via ELISA. Of these mAbs, 284 and 246 clones were reactive to either Gt1a or Gt3a E2 proteins, respectively. This is a sensitive and robust method for future studies investigating B cell responses against the HCV Envelope protein.
Collapse
Affiliation(s)
- Bing-Ru Wu
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Auda A Eltahla
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Elizabeth Keoshkerian
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Melanie R Walker
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Alex Underwood
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Nicholas A Brasher
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - David Agapiou
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Andrew R Lloyd
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia
| | - Rowena A Bull
- School of Medical Sciences and the Kirby Institute, Faculty of Medicine, UNSW Australia, Sydney, NSW 2052, Australia.
| |
Collapse
|
11
|
Ginsenoside compound-K inhibits the activity of B cells through inducing IgD-B cell receptor endocytosis in mice with collagen-induced arthritis. Inflammopharmacology 2019; 27:845-856. [DOI: 10.1007/s10787-019-00608-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 05/25/2019] [Indexed: 01/06/2023]
|
12
|
Signalling circuits that direct early B-cell development. Biochem J 2019; 476:769-778. [PMID: 30842310 DOI: 10.1042/bcj20180565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/11/2019] [Accepted: 02/15/2019] [Indexed: 12/23/2022]
Abstract
In mammals, the B-cell lineage arises from pluripotent progenitors in the bone marrow. During their development, B-cells undergo lineage specification and commitment, followed by expansion and selection. These processes are mediated by regulated changes in gene expression programmes, rearrangements of immunoglobulin (Ig) genes, and well-timed rounds of proliferation and apoptosis. Many of these processes are initiated by environmental factors including cytokines, chemokines, and cell-cell contacts. Developing B-cells process these environmental cues into stage-specific functions via signalling pathways including the PI3K, MAPK, or JAK-STAT pathway. The cytokines FLT3-Ligand and c-Kit-Ligand are important for the early expansion of the B-cell precursors at different developmental stages and conditions. Interleukin 7 is essential for commitment to the B-cell lineage and for orchestrating the Ig recombination machinery. After rearrangement of the immunoglobulin heavy chain, proliferation and apoptosis, and thus selection, are mediated by the clonal pre-B-cell receptor, and, following light chain rearrangement, by the B-cell receptor.
Collapse
|
13
|
Coulter EM, Pepper A, Mele S, Folarin N, Townsend W, Cuthill K, Phillips EH, Patten PEM, Devereux S. In vitro and in vivo evidence for uncoupling of B-cell receptor internalization and signaling in chronic lymphocytic leukemia. Haematologica 2017; 103:497-505. [PMID: 29242301 PMCID: PMC5830387 DOI: 10.3324/haematol.2017.176164] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/12/2017] [Indexed: 12/24/2022] Open
Abstract
B-cell receptor activation, occurring within lymph nodes, plays a key role in the pathogenesis of chronic lymphocytic leukemia and is linked to prognosis. As well as activation of downstream signaling, receptor ligation triggers internalization, transit to acidified endosomes and degradation of ligand-receptor complexes. Herein, we investigated the relationship between these two processes in normal and leukemic B cells. We found that leukemic B cells, particularly anergic cases lacking the capacity to initiate downstream signaling, internalize and accumulate ligand in acidified endosomes more efficiently than normal B cells. Furthermore, ligation of either surface CD79B, a B-cell receptor component required for downstream signaling, or surface Immunoglobulin M (IgM) by cognate agonistic antibody, showed that the two molecules internalize independently of each other in leukemic but not normal B cells. Since association with surface CD79B is required for surface retention of IgM, this suggests that uncoupling of B-cell receptor internalization from signaling may be due to the dissociation of these two molecules in leukemic cells. A comparison of lymph node with peripheral blood cells from chronic lymphocytic leukemia patients showed that, despite recent B-cell receptor activation, lymph node B cells expressed higher levels of surface IgM. This surprising finding suggests that the B-cell receptors of lymph node- and peripheral blood-derived leukemic cells might be functionally distinct. Finally, long-term therapy with the Bruton’s tyrosine kinase inhibitors ibrutinib or acalabrutinib resulted in a switch to an anergic pattern of B-cell receptor function with reduced signaling capacity, surface IgM expression and more efficient internalization.
Collapse
Affiliation(s)
- Eve M Coulter
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Andrea Pepper
- Brighton and Sussex Medical School, Medical research Building, University of Sussex, Brighton
| | - Silvia Mele
- St John's Institute of Dermatology, Department of Genetics and Molecular Medicine, King's College London
| | | | - William Townsend
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Kirsty Cuthill
- Department of Haematological Medicine, Kings College Hospital, London, UK
| | - Elizabeth H Phillips
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Piers E M Patten
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London.,Department of Haematological Medicine, Kings College Hospital, London, UK
| | - Stephen Devereux
- Department of Haematological Medicine, Kings College Hospital, London, UK
| |
Collapse
|
14
|
Dezorella N, Katz BZ, Shapiro M, Polliack A, Perry C, Herishanu Y. SLP76 integrates into the B-cell receptor signaling cascade in chronic lymphocytic leukemia cells and is associated with an aggressive disease course. Haematologica 2016; 101:1553-1562. [PMID: 27443285 DOI: 10.3324/haematol.2015.139154] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 07/12/2016] [Indexed: 01/07/2023] Open
Abstract
I In the last decade, the B-cell receptor has emerged as a pivotal stimulus in the pathogenesis of chronic lymphocytic leukemia, and a very feasible therapeutic target in this disease. B-cell receptor responsiveness in chronic lymphocytic leukemia cells is heterogeneous among patients and correlates with aggressiveness of the disease. Here we show, for the first time, that SLP76, a key scaffold protein in T-cell receptor signaling, is ectopically expressed in chronic lymphocytic leukemia cells, with variable levels among patients, and correlates positively with unmutated immunoglobulin heavy chain variable gene status and ZAP-70 expression. We found that SLP76 was functionally active in chronic lymphocytic leukemia cells. A SYK-dependent basal level of phosphorylated SLP76 exists in the cells, and upon B-cell receptor engagement, SLP76 tyrosine phosphorylation is significantly enhanced concomitantly with increased physical association with BTK. B-cell receptor-induced SLP76 phosphorylation is mediated by upstream signaling events involving LCK and SYK. Knockdown of SLP76 in the cells resulted in decreased induction of BTK, PLCγ2 and IκB phosphorylation, as well as cell viability after B-cell receptor activation with anti-IgM. Consistent with our biochemical findings, high total SLP76 expression in chronic lymphocytic leukemia cells correlated with a more aggressive disease course. IN CONCLUSION SLP76 is ectopically expressed in chronic lymphocytic leukemia cells where it plays a role in B-cell receptor signaling.
Collapse
Affiliation(s)
- Nili Dezorella
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
| | - Ben-Zion Katz
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
| | - Mika Shapiro
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel
| | - Aaron Polliack
- Department of Hematology, Hadassah University Hospital and Hebrew University Medical School, Jerusalem, Israel
| | - Chava Perry
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel
| | - Yair Herishanu
- Department of Hematology, Tel-Aviv Sourasky Medical Center, Jerusalem, Israel .,Sackler Faculty of Medicine, Tel-Aviv University, Jerusalem, Israel
| |
Collapse
|
15
|
Miller H, Castro-Gomes T, Corrotte M, Tam C, Maugel TK, Andrews NW, Song W. Lipid raft-dependent plasma membrane repair interferes with the activation of B lymphocytes. J Cell Biol 2016; 211:1193-205. [PMID: 26694840 PMCID: PMC4687878 DOI: 10.1083/jcb.201505030] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Repair of plasma membrane wounds in B lymphocytes that lack caveolin requires lysosome exocytosis and lipid raft–mediated endocytosis and inhibits activation of the B cell receptor by sequestering lipid rafts. Cells rapidly repair plasma membrane (PM) damage by a process requiring Ca2+-dependent lysosome exocytosis. Acid sphingomyelinase (ASM) released from lysosomes induces endocytosis of injured membrane through caveolae, membrane invaginations from lipid rafts. How B lymphocytes, lacking any known form of caveolin, repair membrane injury is unknown. Here we show that B lymphocytes repair PM wounds in a Ca2+-dependent manner. Wounding induces lysosome exocytosis and endocytosis of dextran and the raft-binding cholera toxin subunit B (CTB). Resealing is reduced by ASM inhibitors and ASM deficiency and enhanced or restored by extracellular exposure to sphingomyelinase. B cell activation via B cell receptors (BCRs), a process requiring lipid rafts, interferes with PM repair. Conversely, wounding inhibits BCR signaling and internalization by disrupting BCR–lipid raft coclustering and by inducing the endocytosis of raft-bound CTB separately from BCR into tubular invaginations. Thus, PM repair and B cell activation interfere with one another because of competition for lipid rafts, revealing how frequent membrane injury and repair can impair B lymphocyte–mediated immune responses.
Collapse
Affiliation(s)
- Heather Miller
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Thiago Castro-Gomes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Matthias Corrotte
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Christina Tam
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Timothy K Maugel
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Norma W Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Wenxia Song
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| |
Collapse
|
16
|
Hüttl S, Kläsener K, Schweizer M, Schneppenheim J, Oberg HH, Kabelitz D, Reth M, Saftig P, Schröder B. Processing of CD74 by the Intramembrane Protease SPPL2a Is Critical for B Cell Receptor Signaling in Transitional B Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:1548-63. [PMID: 26157172 DOI: 10.4049/jimmunol.1403171] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/09/2015] [Indexed: 12/16/2022]
Abstract
The invariant chain (CD74), a chaperone in MHC class II-mediated Ag presentation, is sequentially processed by different endosomal proteases. We reported recently that clearance of the final membrane-bound N-terminal fragment (NTF) of CD74 is mediated by the intramembrane protease signal peptide peptidase-like (SPPL)2a, a process critical for B cell development. In mice, SPPL2a deficiency provokes the accumulation of this NTF in endocytic vesicles, which leads to a B cell maturation arrest at the transitional 1 stage. To define the underlying mechanism, we analyzed the impact of SPPL2a deficiency on signaling pathways involved in B cell homeostasis. We demonstrate that tonic as well as BCR-induced activation of the PI3K/Akt pathway is massively compromised in SPPL2a(-/-) B cells and identify this as major cause of the B cell maturation defect in these mice. Altered BCR trafficking induces a reduction of surface IgM in SPPL2a-deficient B cells, leading to a diminished signal transmission via the BCR and the tyrosine kinase Syk. We provide evidence that in SPPL2a(-/-) mice impaired BCR signaling is to a great extent provoked by the accumulating CD74 NTF, which can interact with the BCR and Syk, and that impaired PI3K/Akt signaling and reduced surface IgM are not directly linked processes. In line with disturbances in PI3K/Akt signaling, SPPL2a(-/-) B cells show a dysregulation of the transcription factor FOXO1, causing elevated transcription of proapoptotic genes. We conclude that SPPL2a-mediated processing of CD74 NTF is indispensable to maintain appropriate levels of tonic BCR signaling to promote B cell maturation.
Collapse
Affiliation(s)
- Susann Hüttl
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Kathrin Kläsener
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Janna Schneppenheim
- Institute of Anatomy, Christian Albrechts University of Kiel, D-24118 Kiel, Germany; and
| | - Hans-Heinrich Oberg
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Dieter Kabelitz
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany;
| |
Collapse
|
17
|
Visentini M, Marrapodi R, Conti V, Mitrevski M, Camponeschi A, Lazzeri C, Carbonari M, Catizone A, Quinti I, Fiorilli M. Dysregulated extracellular signal-regulated kinase signaling associated with impaired B-cell receptor endocytosis in patients with common variable immunodeficiency. J Allergy Clin Immunol 2014; 134:401-10. [PMID: 24792875 DOI: 10.1016/j.jaci.2014.03.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 03/17/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by B-cell dysfunction and, in a subgroup, by expansion of CD21(low) B cells. The CD21(low) B cells display defects in early B-cell receptor (BCR) signaling resembling those of anergic B cells. OBJECTIVE We sought to investigate whether B cells from patients with CVID, like anergic B cells, have defects in extracellular signal-regulated kinase (ERK) phosphorylation and in endocytic trafficking of the BCR. METHODS Using flow cytometry, we evaluated phosphorylated ERK (pERK) expression and internalization of cross-linked BCR in B-cell subsets. The localization of internalized BCR to lysosome-associated membrane protein 1-positive late endosomes was evaluated with confocal microscopy. RESULTS Constitutive pERK levels were increased in naive and IgM(+) memory B cells of patients with CVID compared with those of healthy donors, whereas the pERK increment induced by BCR cross-linking was relatively reduced. Intravenous immunoglobulin administration enhanced these anomalies, but they appeared to be intrinsic to B cells from patients with CVID. Cross-linking-induced BCR endocytosis was decreased in the IgM(+) memory B cells, especially in those with a CD21(low) phenotype, but not in the naive B cells of patients with CVID with CD21(low) expansion. Internalized BCR localized normally to late endosomes. Pharmacologic inhibition of ERK phosphorylation suppressed BCR endocytosis in B cells of healthy patients and those with CVID. CONCLUSIONS The B cells of patients with CVID with CD21(low) B-cell expansion resemble anergic B cells based on high constitutive pERK expression. The IgM(+) memory B cells of these patients, especially those that are CD21(low), have a defect in BCR endocytosis seemingly caused by dysregulated ERK signaling.
Collapse
Affiliation(s)
- Marcella Visentini
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy
| | - Ramona Marrapodi
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy
| | - Valentina Conti
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Milica Mitrevski
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy
| | | | - Cristina Lazzeri
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy
| | - Maurizio Carbonari
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy
| | - Angela Catizone
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, Rome, Italy
| | - Isabella Quinti
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Massimo Fiorilli
- Department of Clinical Immunology, Sapienza University of Rome, Rome, Italy.
| |
Collapse
|
18
|
Packham G, Krysov S, Allen A, Savelyeva N, Steele AJ, Forconi F, Stevenson FK. The outcome of B-cell receptor signaling in chronic lymphocytic leukemia: proliferation or anergy. Haematologica 2014; 99:1138-48. [PMID: 24986876 PMCID: PMC4077074 DOI: 10.3324/haematol.2013.098384] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/24/2014] [Indexed: 01/09/2023] Open
Abstract
Biologists and clinicians agree that the B-cell receptor influences the behavior of chronic lymphocytic leukemia, and promising new drugs are aimed at receptor-associated kinases. Engagement of surface immunoglobulin by antigen is a key driver of malignant cells with outcome influenced by the nature of the cell, the level of stimulation and the microenvironment. Analysis of surface immunoglobulin-mediated signaling in the two major disease subsets defined by IGHV mutational status reveals bifurcation of responses toward proliferation or anergy. Mutated chronic lymphocytic leukemia, generally of relatively good prognosis, is mainly, but not exclusively, driven towards anergy in vivo. In contrast, unmutated chronic lymphocytic leukemia shows less evidence for anergy in vivo retaining more responsiveness to surface immunoglobulin M-mediated signaling, possibly explaining increased tumor progression. Expression and function of surface immunoglobulin M in unmutated chronic lymphocytic leukemia appear rather homogeneous, but mutated chronic lymphocytic leukemia exhibits a highly heterogeneous profile that may relate to further variable clinical behavior within this subset. Anergy should increase susceptibility to apoptosis but, in leukemic cells, this may be countered by overexpression of the B-cell lymphoma-2 survival protein. Maintained anergy spreads to chemokines and adhesion molecules, restraining homing and migration. However, anergy is not necessarily completely benign, being able to reverse and regenerate surface immunoglobulin M-mediated responses. A two-pronged attack on proliferative and anti-apoptotic pathways may succeed. Increased understanding of how chronic lymphocytic leukemia cells are driven to anergy or proliferation should reveal predictive biomarkers of progression and of likely response to kinase inhibitors, which could assist therapeutic decisions.
Collapse
MESH Headings
- Animals
- Antigens/immunology
- Antigens/metabolism
- Apoptosis
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Cell Proliferation
- Clonal Anergy/immunology
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction
Collapse
Affiliation(s)
- Graham Packham
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Serge Krysov
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Alex Allen
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Natalia Savelyeva
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Andrew J Steele
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Francesco Forconi
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| | - Freda K Stevenson
- Cancer Research UK Centre, Faculty of Medicine, University of Southampton, UK
| |
Collapse
|
19
|
Séïté JF, Goutsmedt C, Youinou P, Pers JO, Hillion S. Intravenous immunoglobulin induces a functional silencing program similar to anergy in human B cells. J Allergy Clin Immunol 2014; 133:181-8.e1-9. [DOI: 10.1016/j.jaci.2013.08.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 12/29/2022]
|
20
|
|
21
|
Bartlett A, Buhlmann JE, Stone J, Lim B, Barrington RA. Multiple checkpoint breach of B cell tolerance in Rasgrp1-deficient mice. THE JOURNAL OF IMMUNOLOGY 2013; 191:3605-13. [PMID: 23997211 DOI: 10.4049/jimmunol.1202892] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Lymphopenic hosts offer propitious microenvironments for expansion of autoreactive B and T cells. Despite this, many lymphopenic hosts do not develop autoimmune disease, suggesting that additional factors are required for breaching self-tolerance in the setting of lymphopenia. Mice deficient in guanine nucleotide exchange factor Rasgrp1 develop a lymphoproliferative disorder with features of human systemic lupus erythematosus. Early in life, Rasgrp1-deficient mice have normal B cell numbers but are T lymphopenic, leading to defective homeostatic expansion of CD4 T cells. To investigate whether B cell-intrinsic mechanisms also contribute to autoimmunity, Rasgrp1-deficient mice were bred to mice containing a knockin autoreactive BCR transgene (564Igi), thereby allowing the fate of autoreactive B cells to be assessed. During B cell development, the frequency of receptor-edited 564Igi B cells was reduced in Rasrp1-deficient mice compared with Rasgrp1-sufficient littermate control mice, suggesting that tolerance was impaired. In addition, the number of 564Igi transitional B cells was increased in Rasgrp1-deficient mice compared with control mice. Immature 564Igi B cells in bone marrow and spleen lacking RasGRP1 expressed lower levels of Bim mRNA and protein, suggesting that autoreactive B cells elude clonal deletion during development. Concomitant with increased serum autoantibodies, Rasgrp1-deficient mice developed spontaneous germinal centers at 8-10 wk of age. The frequency and number of 564Igi B cells within these germinal centers were significantly increased in Rasgrp1-deficient mice relative to control mice. Taken together, these studies suggest that autoreactive B cells lacking Rasgrp1 break central and peripheral tolerance through both T cell-independent and -dependent mechanisms.
Collapse
Affiliation(s)
- Amber Bartlett
- Department of Microbiology and Immunology, University of South Alabama, Mobile, AL 36688
| | | | | | | | | |
Collapse
|
22
|
Weinstock-Guttman B, Horakova D, Zivadinov R, Tamaño-Blanco M, Badgett D, Tyblova M, Vaneckova M, Seidl Z, Krasensky J, Bergsland N, Ramasamy DP, Hagemeier J, Havrdova E, Ramanathan M. Interactions of serum cholesterol with anti-herpesvirus responses affect disease progression in clinically isolated syndromes. J Neuroimmunol 2013; 263:121-7. [PMID: 23916695 DOI: 10.1016/j.jneuroim.2013.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 06/26/2013] [Accepted: 07/11/2013] [Indexed: 01/15/2023]
Abstract
OBJECTIVES To investigate whether anti-herpesvirus antibodies are associated with serum cholesterol profiles in clinically isolated syndromes (CIS). METHODS Pre-treatment serum samples from 118 high-risk CIS patients were analyzed for IgG antibodies against cytomegalovirus (anti-CMV), Epstein Barr virus (EBV) viral capsid antigen (VCA) and EBV nuclear antigen-1 (EBNA-1). A lipid profile consisting of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) was obtained. Clinical and MRI assessments were obtained at baseline, 6, 12, and 24 months after start of interferon-beta treatment. RESULTS The study included 118 CIS patients (77 females, 41 males, 65.3% female; mean age: 28.1±SD 8.1 years). Anti-EBV EBNA-1 antibody levels were associated with LDL-C (p=0.009) and TC (p=0.008) levels. Anti-CMV positivity status was associated with reduced time to relapse (p=0.006) and the greater number of relapses (p=0.009) in patients with high HDL-C. Anti-EBV VCA antibody levels were associated with greater number of new T2 lesions (p=0.002) and with increased brain atrophy (p<0.001) in patients with high LDL-C. CONCLUSIONS Our results indicate that higher levels of anti-EBV EBNA-1 antibodies are associated with higher LDL-C and TC levels. Anti-CMV positive individuals have greater disease progression in the presence of higher HDL-C levels. Individuals with higher levels of anti-EBV VCA antibodies have greater progression on MRI measures in the presence of higher LDL-C.
Collapse
|
23
|
Pye DS, Rubio I, Pusch R, Lin K, Pettitt AR, Till KJ. Chemokine unresponsiveness of chronic lymphocytic leukemia cells results from impaired endosomal recycling of Rap1 and is associated with a distinctive type of immunological anergy. THE JOURNAL OF IMMUNOLOGY 2013; 191:1496-504. [PMID: 23804711 DOI: 10.4049/jimmunol.1203484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Trafficking of malignant lymphocytes is fundamental to the biology of chronic lymphocytic leukemia (CLL). Transendothelial migration (TEM) of normal lymphocytes into lymph nodes requires the chemokine-induced activation of Rap1 and αLβ2 integrin. However, in most cases of CLL, Rap1 is refractory to chemokine stimulation, resulting in failed αLβ2 activation and TEM unless α4β1 is coexpressed. In this study, we show that the inability of CXCL12 to induce Rap1 GTP loading in CLL cells results from failure of Rap1-containing endosomes to translocate to the plasma membrane. Furthermore, failure of chemokine-induced Rap1 translocation/GTP loading was associated with a specific pattern of cellular IgD distribution resembling that observed in normal B cells anergized by DNA-based Ags. Anergic features and chemokine unresponsiveness could be simultaneously reversed by culturing CLL cells ex vivo, suggesting that these two features are coupled and driven by stimuli present in the in vivo microenvironment. Finally, we show that failure of Rap1 translocation/GTP loading is linked to defective activation of phospholipase D1 and its upstream activator Arf1. Taken together, our findings indicate that chemokine unresponsiveness in CLL lymphocytes results from failure of Arf1/phospholipase D1-mediated translocation of Rap1 to the plasma membrane for GTP loading and may be a specific feature of anergy induced by DNA Ags.
Collapse
Affiliation(s)
- Derek S Pye
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, United Kingdom
| | | | | | | | | | | |
Collapse
|
24
|
Abstract
B-cell receptor (BCR) triggering and responsiveness have a crucial role in the survival and expansion of chronic lymphocytic leukemia (CLL) clones. Analysis of in vitro response of CLL cells to BCR triggering allowed the definition of 2 main subsets of patients and lack of signaling capacity was associated with constitutive activation of extracellular-regulated kinases 1/2 (ERK1/2) and nuclear factor of activated T cells c1 (NF-ATc1), consistent with the idea that at least one group of CLL patients derives from the abnormal expansion of anergic B cells. In the present work, we further investigated the anergic subset of CLL (defined as the one with constitutive ERK1/2 phosphorylation) and found that it is characterized by low levels of surface immunoglobulin M and impairment of calcium mobilization after BCR engagement in vitro. Chronic BCR triggering promoted CLL cell survival selectively in phosphorylated ERK1/2 samples and the use of mitogen-activated protein kinase and NF-AT signaling inhibitors specifically induced apoptosis in this group of patients. Apoptosis induction was preceded by an initial phase of anergy reversal consisting in the loss of ERK phosphorylation and NF-AT nuclear translocation and by the restoration of BCR responsiveness, reinforcing the idea that the anergic program favors the survival of leukemic lymphocytes.
Collapse
|
25
|
Kendall PL, Case JB, Sullivan AM, Holderness JS, Wells KS, Liu E, Thomas JW. Tolerant anti-insulin B cells are effective APCs. THE JOURNAL OF IMMUNOLOGY 2013; 190:2519-26. [PMID: 23396943 DOI: 10.4049/jimmunol.1202104] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autoreactive B lymphocytes that are not culled by central tolerance in the bone marrow frequently enter the peripheral repertoire in a state of functional impairment, termed anergy. These cells are recognized as a liability for autoimmunity, but their contribution to disease is not well understood. Insulin-specific 125Tg B cells support T cell-mediated type 1 diabetes in NOD mice, despite being anergic to B cell mitogens and T cell-dependent immunization. Using this model, the potential of anergic, autoreactive B cells to present Ag and activate T cells was investigated. The data show that 1) insulin is captured and rapidly internalized by 125Tg BCRs, 2) these Ag-exposed B cells are competent to activate both experienced and naive CD4(+) T cells, 3) anergic 125Tg B cells are more efficient than naive B cells at activating T cells when Ag is limiting, and 4) 125Tg B cells are competent to generate low-affinity insulin B chain epitopes necessary for activation of diabetogenic anti-insulin BDC12-4.1 T cells, indicating the pathological relevance of anergic B cells in type 1 diabetes. Thus, phenotypically tolerant B cells that are retained in the repertoire may promote autoimmunity by driving activation and expansion of autoaggressive T cells via Ag presentation.
Collapse
Affiliation(s)
- Peggy L Kendall
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | | | | | | | | | | | | |
Collapse
|
26
|
Encounter with antigen-specific primed CD4 T cells promotes MHC class II degradation in dendritic cells. Proc Natl Acad Sci U S A 2012; 109:19380-5. [PMID: 23129633 DOI: 10.1073/pnas.1213868109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Major histocompatibility complex class II molecules (MHC-II) on antigen presenting cells (APCs) engage the TCR on antigen-specific CD4 T cells, thereby providing the specificity required for T cell priming and the induction of an effective immune response. In this study, we have asked whether antigen-loaded dendritic cells (DCs) that have been in contact with antigen-specific CD4 T cells retain the ability to stimulate additional naïve T cells. We show that encounter with antigen-specific primed CD4 T cells induces the degradation of surface MHC-II in antigen-loaded DCs and inhibits the ability of these DCs to stimulate additional naïve CD4 T cells. Cross-linking with MHC-II mAb as a surrogate for T-cell engagement also inhibits APC function and induces MHC-II degradation by promoting the clustering of MHC-II present in lipid raft membrane microdomains, a process that leads to MHC-II endocytosis and degradation in lysosomes. Encounter of DCs with antigen-specific primed T cells or engagement of MHC-II with antibodies promotes the degradation of both immunologically relevant and irrelevant MHC-II molecules. These data demonstrate that engagement of MHC-II on DCs after encounter with antigen-specific primed CD4 T cells promotes the down-regulation of cell surface MHC-II in DCs, thereby attenuating additional activation of naïve CD4 T cells by these APCs.
Collapse
|
27
|
The growth of B cell receptor microcluster is a universal response of B cells encountering antigens with different motion features. Protein Cell 2012; 3:545-58. [PMID: 22773344 DOI: 10.1007/s13238-012-2054-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 06/15/2012] [Indexed: 10/28/2022] Open
Abstract
B lymphocyte cell senses and acquires foreign antigens through clonal distributed B cell receptors (BCRs) expressed on the surface of plasma membrane. The presentation formats of antigens are quite diverse. Based on their Brownian diffusion mobility, there are three forms: free mobile soluble antigens, lateral mobile membrane bound antigens, and fixed immobile antigens. Here, using high resolution high speed live cell imaging approaches, we provide evidence that BCR microclusters are formed on the surface of B cells shortly after B cell's encountering of antigens with each format of motion features. Through high speed live cell imaging, we determine that these BCR microclusters show dynamic growth feature and by doing so function as the basic platforms for B cells to acquire the antigens. We propose that the formation and dynamic growth of BCR microcluster is a universal mechanism for B cell to response to antigens with diverse motion features.
Collapse
|
28
|
O'Neill SK, Getahun A, Gauld SB, Merrell KT, Tamir I, Smith MJ, Dal Porto JM, Li QZ, Cambier JC. Monophosphorylation of CD79a and CD79b ITAM motifs initiates a SHIP-1 phosphatase-mediated inhibitory signaling cascade required for B cell anergy. Immunity 2011; 35:746-56. [PMID: 22078222 DOI: 10.1016/j.immuni.2011.10.011] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 08/16/2011] [Accepted: 10/13/2011] [Indexed: 12/17/2022]
Abstract
Anergic B cells are characterized by impaired signaling and activation after aggregation of their antigen receptors (BCR). The molecular basis of this impairment is not understood. In studies reported here, Src homology-2 (SH2)-containing inositol 5-phosphatase SHIP-1 and its adaptor Dok-1 were found to be constitutively phosphorylated in anergic B cells, and activation of this inhibitory circuit was dependent on Src-family kinase activity and consequent to biased BCR immunoreceptor tyrosine-based activation motif (ITAM) monophosphorylation. B cell-targeted deletion of SHIP-1 caused severe lupus-like disease. Moreover, absence of SHIP-1 in B cells led to loss of anergy as indicated by restoration of BCR signaling, loss of anergic surface phenotype, and production of autoantibodies. Thus, chronic BCR signals maintain anergy in part via ITAM monophosphorylation-directed activation of an inhibitory signaling circuit involving SHIP-1 and Dok-1.
Collapse
Affiliation(s)
- Shannon K O'Neill
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish Health, Denver, CO 80206, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Kometani K, Yamada T, Sasaki Y, Yokosuka T, Saito T, Rajewsky K, Ishiai M, Hikida M, Kurosaki T. CIN85 drives B cell responses by linking BCR signals to the canonical NF-kappaB pathway. ACTA ACUST UNITED AC 2011; 208:1447-57. [PMID: 21708930 PMCID: PMC3135365 DOI: 10.1084/jem.20102665] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
CIN85 transduces B cell receptor signals to IKK-β, and its expression in B cells is essential for T cell–independent type II antibody responses in mice. CIN85, an adaptor protein which binds the C-terminal domain of tyrosine phosphorylated Cbl and Cbl-b, has been thought to be involved in the internalization and subsequent degradation of receptors. However, its physiological function remains unclear. To determine its role in B cells, we used Mb1-cre to generate mice with a B cell–specific deletion of CIN85. These mice had impaired T cell–independent type II antibody responses in vivo and diminished IKK-β activation and cellular responses to B cell receptor (BCR) cross-linking in vitro. Introduction of a constitutively active IKK-β construct corrected the defective antibody responses as well as cellular responses in the mutant mice. Together, our results suggest that CIN85 links the BCR to IKK-β activation, thereby contributing to T cell–independent immune responses.
Collapse
Affiliation(s)
- Kohei Kometani
- Laboratory for Lymphocyte Differentiation, RIKEN Research Center for Allergy and Immunology, Turumi-ku, Kanagawa 230-0045, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Baumgarth N. The double life of a B-1 cell: self-reactivity selects for protective effector functions. Nat Rev Immunol 2010; 11:34-46. [PMID: 21151033 DOI: 10.1038/nri2901] [Citation(s) in RCA: 657] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During their development, B and T cells with self-reactive antigen receptors are generally deleted from the repertoire to avoid autoimmune diseases. Paradoxically, innate-like B-1 cells in mice are positively selected for self-reactivity and form a pool of long-lived, self-renewing B cells that produce most of the circulating natural IgM antibodies. This Review provides an overview of the developmental processes that shape the B-1 cell pool in mice, outlines the functions of B-1 cells in both the steady state and during host defence, and discusses possible functional B-1 cell homologues that exist in humans.
Collapse
Affiliation(s)
- Nicole Baumgarth
- Center for Comparative Medicine, University of California, Davis, California 95616, USA.
| |
Collapse
|
31
|
Clark MR, Tanaka A, Powers SE, Veselits M. Receptors, subcellular compartments and the regulation of peripheral B cell responses: the illuminating state of anergy. Mol Immunol 2010; 48:1281-6. [PMID: 21144589 DOI: 10.1016/j.molimm.2010.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/13/2010] [Accepted: 10/26/2010] [Indexed: 12/22/2022]
Abstract
Signals through the B cell antigen receptor (BCR) are necessary but not sufficient for cellular activation. Co-stimulatory signals must be provided through other immune recognition receptor systems, such as MHC class II/CD40 and the toll-like receptor (TLR) 9 that can only productively acquire their ligands in the processive environment of specialized late endosomes (MHC class II containing compartment or MIIC). It has long been appreciated that the BCR, by effectively capturing complex antigens and delivering them to late endosomes, is the link between activation events on the cell surface and those dependent on late endosomes. However, it has become increasingly apparent that the BCR also directs the translocation of MHC class II and TLR9 into the MIIC and that the endocytic flow of these receptors coincides with that of the BCR. This likely ensures close apposition of receptor complexes within the MIIC and the efficient transfer of ligands from the BCR to MHC class II and TLR9. This complex orchestration of receptor endocytic movement is dependent upon the quality of signals elicited through the BCR. Failure to activate specific signaling pathways, such as occurs in anergic B cells, prevents the entry of the BCR and TLR9 into the MIIC and abrogates TLR9 activation. Like anergy, this block in endocytic trafficking is rapidly reversible. These findings indicate that cellular responsiveness can be determined by mechanisms that control the subcellular location of important immune recognition receptors.
Collapse
Affiliation(s)
- Marcus R Clark
- Section of Rheumatology, Department of Medicine and Knapp Center for Lupus and Immunological Research, University of Chicago, 5841 S. Maryland Ave, Chicago, IL 60637, USA.
| | | | | | | |
Collapse
|
32
|
Abstract
Rituximab (RTX), a monoclonal antibody directed against the CD20 protein, is a drug commonly used in the treatment of B-cell-derived lymphoid neoplasias and of antibody-mediated autoimmune diseases. In addition to cell- and complement-mediated B-cell depletion, RTX is thought to inhibit B-cell survival and proliferation through negative regulation of canonical signaling pathways involving Akt, ERK, and mammalian target of rapamycin. However, surprisingly, although B-cell receptor (BCR) signaling has been considered critical for normal and more recently, for neoplastic B cells, the hypothesis that RTX could target BCR has never been investigated. Using follicular lymphoma cell lines as models, as well as normal B cells, we show here, for the first time, that pretreatment with RTX results in a time-dependent inhibition of the BCR-signaling cascade involving Lyn, Syk, PLC gamma 2, Akt, and ERK, and calcium mobilization. The inhibitory effect of RTX correlates with decrease of raft-associated cholesterol, complete inhibition of BCR relocalization into lipid raft microdomains, and down-regulation of BCR immunoglobulin expression. Thus, RTX-mediated alteration of BCR expression, dynamics, and signaling might contribute to the immunosuppressive activity of the drug.
Collapse
|
33
|
Endocytic sequestration of the B cell antigen receptor and toll-like receptor 9 in anergic cells. Proc Natl Acad Sci U S A 2009; 106:6262-7. [PMID: 19332776 DOI: 10.1073/pnas.0812922106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In autoimmune prone murine strains, sequential engagement of the B cell antigen receptor (BCR) on the cell surface and toll-like receptors (TLRs) in late endosomes is necessary and sufficient for secretion of autoantibodies. However, ubiquitous nucleoprotein self-antigens fail to elicit productive TLR activation, and break self-tolerance in anergic DNA-reactive B cells. The mechanisms limiting TLR activation in these cells are largely unknown. Here, we demonstrate that in anergic 3H9/Vkappa8 and Ars/A1 B cells the normal endocytic transit of both the ligated BCR and TLR9 into late endosomes is abrogated. The BCR and TLR9 arrest together just outside late endosomes, indicating that they enter this compartment along a single, regulated endocytic route. Access to late endosomes could be restored by reversing anergy through several methods, including conferring genetic susceptibility to autoimmunity, complementing proximal BCR signaling or by preventing BCR binding to self-antigen. Downstream of the BCR, JNK, which is activated in naive but not anergic B cells, regulated entry into late endosomes. Restoration of BCR and TLR9 endocytic trafficking rescued TLR9 activation by BCR-captured ligands. These results indicate that B cell anergy is reinforced by the exclusion of both TLRs and their BCR captured ligands from subcellular environments necessary for TLR activation.
Collapse
|
34
|
Hernanz-Falcón P, Joffre O, Williams DL, Reis e Sousa C. Internalization of Dectin-1 terminates induction of inflammatory responses. Eur J Immunol 2009; 39:507-13. [PMID: 19130473 PMCID: PMC2699426 DOI: 10.1002/eji.200838687] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dectin-1 is a pattern-recognition receptor recognizing β-(1,3)-glucans found on fungal cell walls. Dectin-1 plays an important role in immunity to fungi by mediating phagocytic clearance of fungal particles and inducing transcription of innate response genes. We show here that the two processes are linked and that Dectin-1 signalling for inflammation is attenuated by phagocytosis. Blocking Dectin-1 ligand-dependent internalization using either actin polymerization or dynamin inhibitors, large non-phagocytosable β-glucan particles or poorly phagocytic cells leads in all cases to enhanced and sustained activation of downstream signalling pathways and culminates in production of high levels of pro-inflammatory cytokines. These findings establish the importance of phagocytosis not only in the clearance of pathogens, but also in the modulation of pattern-recognition receptor signalling and strongly suggest that internalization is the first step to attenuation of Dectin-1-mediated pro-inflammatory responses.
Collapse
|
35
|
Schram BR, Tze LE, Ramsey LB, Liu J, Najera L, Vegoe AL, Hardy RR, Hippen KL, Farrar MA, Behrens TW. B cell receptor basal signaling regulates antigen-induced Ig light chain rearrangements. THE JOURNAL OF IMMUNOLOGY 2008; 180:4728-41. [PMID: 18354197 DOI: 10.4049/jimmunol.180.7.4728] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BCR editing in the bone marrow contributes to B cell tolerance by orchestrating secondary Ig rearrangements in self-reactive B cells. We have recently shown that loss of the BCR or a pharmacologic blockade of BCR proximal signaling pathways results in a global "back-differentiation" response in which immature B cells down-regulate genes important for the mature B cell program and up-regulate genes characteristic of earlier stages of B cell development. These observations led us to test the hypothesis that self-Ag-induced down-regulation of the BCR, and not self-Ag-induced positive signals, lead to Rag induction and hence receptor editing. Supporting this hypothesis, we found that immature B cells from xid (x-linked immunodeficiency) mice induce re-expression of a Rag2-GFP bacterial artificial chromosome reporter as well as wild-type immature B cells following Ag incubation. Incubation of immature B cells with self-Ag leads to a striking reversal in differentiation to the pro-/pre-B stage of development, consistent with the idea that back-differentiation results in the reinduction of genes required for L chain rearrangement and receptor editing. Importantly, Rag induction, the back-differentiation response to Ag, and editing in immature and pre-B cells are inhibited by a combination of phorbol ester and calcium ionophore, agents that bypass proximal signaling pathways and mimic BCR signaling. Thus, mimicking positive BCR signals actually inhibits receptor editing. These findings support a model whereby Ag-induced receptor editing is inhibited by BCR basal signaling on developing B cells; BCR down-regulation removes this basal signal, thereby initiating receptor editing.
Collapse
Affiliation(s)
- Brian R Schram
- Center for Immunology, Department of Medicine, University of Minnesota Medical School, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Functional implications of plasma membrane condensation for T cell activation. PLoS One 2008; 3:e2262. [PMID: 18509459 PMCID: PMC2384009 DOI: 10.1371/journal.pone.0002262] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 04/19/2008] [Indexed: 12/20/2022] Open
Abstract
The T lymphocyte plasma membrane condenses at the site of activation but the functional significance of this receptor-mediated membrane reorganization is not yet known. Here we demonstrate that membrane condensation at the T cell activation sites can be inhibited by incorporation of the oxysterol 7-ketocholesterol (7KC), which is known to prevent the formation of raft-like liquid-ordered domains in model membranes. We enriched T cells with 7KC, or cholesterol as control, to assess the importance of membrane condensation for T cell activation. Upon 7KC treatment, T cell antigen receptor (TCR) triggered calcium fluxes and early tyrosine phosphorylation events appear unaltered. However, signaling complexes form less efficiently on the cell surface, fewer phosphorylated signaling proteins are retained in the plasma membrane and actin restructuring at activation sites is impaired in 7KC-enriched cells resulting in compromised downstream activation responses. Our data emphasizes lipids as an important medium for the organization at T cell activation sites and strongly indicates that membrane condensation is an important element of the T cell activation process.
Collapse
|
37
|
The Multifunctional Role of Antibodies in the Protective Response to Bacterial T Cell-Independent Antigens. Curr Top Microbiol Immunol 2008; 319:17-40. [DOI: 10.1007/978-3-540-73900-5_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
38
|
Brezski RJ, Monroe JG. B cell antigen receptor-induced Rac1 activation and Rac1-dependent spreading are impaired in transitional immature B cells due to levels of membrane cholesterol. THE JOURNAL OF IMMUNOLOGY 2007; 179:4464-72. [PMID: 17878342 DOI: 10.4049/jimmunol.179.7.4464] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The BCR-triggered responses of mature and transitional immature B cells differ at both the biochemical and functional level. In this study, we show that in mature B cells, BCR signaling triggers Vav phosphorylation and Rac1 activation. Furthermore, we demonstrate that although downstream actin-dependent BCR capping is independent of Rac1 activation, actin-dependent membrane ruffling and cell spreading are Rac1-dependent processes. In contrast, BCR-induced Vav phosphorylation and Rac1 activation is impaired in transitional immature B cells, resulting in defects in actin polymerization-dependent spreading and membrane ruffling while Rac1-independent BCR capping remains intact. Because transitional immature murine B cells maintain lower steady-state levels of plasma membrane cholesterol, we augmented their levels to that of mature B cells and found that BCR-induced Rac1 activation and Rac1-dependent membrane ruffling and cell spreading were restored. These studies provide a direct link between B cell cholesterol levels and downstream cellular signaling processes.
Collapse
Affiliation(s)
- Randall J Brezski
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | |
Collapse
|
39
|
Kumar KR, Mohan C. Understanding B-cell tolerance through the use of immunoglobulin transgenic models. Immunol Res 2007; 40:208-23. [DOI: 10.1007/s12026-007-8008-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
40
|
Xia M, Wang Q, Zhu H, Ma J, Hou M, Tang Z, Li J, Ling W. Lipid rafts regulate cellular CD40 receptor localization in vascular endothelial cells. Biochem Biophys Res Commun 2007; 361:768-74. [PMID: 17678876 DOI: 10.1016/j.bbrc.2007.07.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 07/18/2007] [Indexed: 10/23/2022]
Abstract
Cholesterol enriched lipid rafts are considered to function as platforms involved in the regulation of membrane receptor signaling complex through the clustering of signaling molecules. In this study, we tested whether these specialized membrane microdomains affect CD40 localization in vitro and in vivo. Here, we provide evidence that upon CD40 ligand stimulation, endogenous and exogenous CD40 receptor is rapidly mobilized into lipid rafts compared with unstimulated HAECs. Efficient binding between CD40L and CD40 receptor also increases amounts of CD40 protein levels in lipid rafts. Deficiency of intracellular conserved C terminus of the CD40 cytoplasmic tail impairs CD40 partitioning in raft. Raft disorganization after methyl-beta-cyclodextrin treatment diminishes CD40 localization into rafts. In vivo studies show that elevation of circulating cholesterol in high-cholesterol fed rabbits increases the cholesterol content and CD40 receptor localization in lipid rafts. These findings identify a physiological role for membrane lipid rafts as a critical regulator of CD40-mediated signal transduction and raise the possibility that certain pathologic conditions may be treated by altering CD40 signaling with drugs affecting its raft localization.
Collapse
Affiliation(s)
- Min Xia
- Department of Nutrition, School of Public Health, Sun Yat-Sen University (Northern Campus), 74 Zhongshan Road 2, Guangzhou, Guangdong Province 510080, PR China
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Gupta N, DeFranco AL. Lipid rafts and B cell signaling. Semin Cell Dev Biol 2007; 18:616-26. [PMID: 17719248 PMCID: PMC2169358 DOI: 10.1016/j.semcdb.2007.07.009] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Revised: 07/20/2007] [Accepted: 07/20/2007] [Indexed: 12/12/2022]
Abstract
B cells comprise an essential component of the humoral immune system. They are equipped with the unique ability to synthesize and secrete pathogen-neutralizing antibodies, and share with professional antigen presenting cells the ability to internalize foreign antigens, and process them for presentation to helper T cells. Recent evidence indicates that specialized cholesterol- and glycosphingolipid-rich microdomains in the plasma membrane commonly referred to as lipid rafts, serve to compartmentalize key signaling molecules during the different stages of B cell activation including B cell antigen receptor (BCR)-initiated signal transduction, endocytosis of BCR-antigen complexes, loading of antigenic peptides onto MHC class II molecules, MHC-II associated antigen presentation to helper T cells, and receipt of helper signals via the CD40 receptor. Here we review the recent literature arguing for a role of lipid rafts in the spatial organization of B cell function.
Collapse
Affiliation(s)
- Neetu Gupta
- Department of Microbiology & Immunology, University of California, San Francisco, San Francisco, CA 94143, United States.
| | | |
Collapse
|
42
|
Choi S, Schwartz RH. Molecular mechanisms for adaptive tolerance and other T cell anergy models. Semin Immunol 2007; 19:140-52. [PMID: 17400472 PMCID: PMC2045643 DOI: 10.1016/j.smim.2007.02.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 02/16/2007] [Indexed: 01/09/2023]
Abstract
Since the original description of T cell anergy in CD4 clones from mice and humans, a number of different unresponsive states have been described, both in vivo and in vitro, that have been called anergic. While initial attempts were made to understand the similarities between the different models, it has now become clear from biochemical experiments that many of them have different molecular mechanisms underlying their unresponsiveness. In this review we will detail our own work on the in vivo model referred to as adaptive tolerance and then attempt to compare this biochemical state to the multitude of other states that have been described in the literature.
Collapse
Affiliation(s)
- Seeyoung Choi
- National Institutes of Health, LCMI, NIAID, Bethesda, MD 20892-0420, USA
| | | |
Collapse
|
43
|
Gobessi S, Laurenti L, Longo PG, Sica S, Leone G, Efremov DG. ZAP-70 enhances B-cell-receptor signaling despite absent or inefficient tyrosine kinase activation in chronic lymphocytic leukemia and lymphoma B cells. Blood 2006; 109:2032-9. [PMID: 17038529 DOI: 10.1182/blood-2006-03-011759] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Expression of ZAP-70 is an important negative prognostic factor in chronic lymphocytic leukemia (CLL). This protein tyrosine kinase is a key mediator of T-cell receptor (TCR) signaling and is structurally homologous to Syk, which plays an analogous role in B-cell receptor (BCR) signaling. Recent studies indicate that ZAP-70 may participate in BCR signaling as well, but the mechanism of action is not completely understood. We have now compared antigen receptor-induced activation of ZAP-70 in B cells and T cells by analyzing phosphorylation of critical regulatory tyrosine residues. We show that BCR-mediated activation of ZAP-70 is very inefficient in CLL and lymphoma B cells and is negligible when compared to activation of Syk. Despite the inefficient catalytic activation, the ability of ZAP-70 to recruit downstream signaling molecules in response to antigen receptor stimulation appeared relatively preserved. Moreover, ectopic expression of ZAP-70 enhanced and prolonged activation of several key mediators of BCR signaling, such as the Syk, ERK, and Akt kinases, and decreased the rate of ligand-mediated BCR internalization. We conclude that the role of ZAP-70 in BCR signaling is quite distinct from its role in TCR signaling and is likely mediated by inhibition of events that terminate the signaling response.
Collapse
Affiliation(s)
- Stefania Gobessi
- International Centre for Genetic Engineering and Biotechnology (ICGEB) Outstation-Monterotondo, Consiglio Nazionale delle Ricerche (CNR) Campus Adriano Buzzati-Traverso, Rome, Italy
| | | | | | | | | | | |
Collapse
|
44
|
Bléry M, Tze L, Miosge LA, Jun JE, Goodnow CC. Essential role of membrane cholesterol in accelerated BCR internalization and uncoupling from NF-κB in B cell clonal anergy. J Biophys Biochem Cytol 2006. [DOI: 10.1083/jcb1742oia5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|