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Fan S, Kang B, Li S, Li W, Chen C, Chen J, Deng L, Chen D, Zhou J. Exploring the multifaceted role of RASGRP1 in disease: immune, neural, metabolic, and oncogenic perspectives. Cell Cycle 2024; 23:722-746. [PMID: 38865342 PMCID: PMC11229727 DOI: 10.1080/15384101.2024.2366009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 11/25/2023] [Indexed: 06/14/2024] Open
Abstract
RAS guanyl releasing protein 1 (RASGRP1) is a guanine nucleotide exchange factor (GEF) characterized by the presence of a RAS superfamily GEF domain. It functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor, specifically activating RAS through the exchange of bound GDP for GTP. Activation of RAS by RASGRP1 has a wide range of downstream effects at the cellular level. Thus, it is not surprising that many diseases are associated with RASGRP1 disorders. Here, we present an overview of the structure and function of RASGRP1, its crucial role in the development, expression, and regulation of immune cells, and its involvement in various signaling pathways. This review comprehensively explores the relationship between RASGRP1 and various diseases, elucidates the underlying molecular mechanisms of RASGRP1 in each disease, and identifies potential therapeutic targets. This study provides novel insights into the role of RASGRP1 in insulin secretion and highlights its potential as a therapeutic target for diabetes. The limitations and challenges associated with studying RASGRP1 in disease are also discussed.
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Affiliation(s)
- Shangzhi Fan
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Bo Kang
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Shaoqian Li
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Weiyi Li
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Canyu Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jixiang Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Lijing Deng
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Danjun Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jiecan Zhou
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
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2
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Harley ITW, Allison K, Scofield RH. Polygenic autoimmune disease risk alleles impacting B cell tolerance act in concert across shared molecular networks in mouse and in humans. Front Immunol 2022; 13:953439. [PMID: 36090990 PMCID: PMC9450536 DOI: 10.3389/fimmu.2022.953439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/19/2022] [Indexed: 11/23/2022] Open
Abstract
Most B cells produced in the bone marrow have some level of autoreactivity. Despite efforts of central tolerance to eliminate these cells, many escape to periphery, where in healthy individuals, they are rendered functionally non-responsive to restimulation through their antigen receptor via a process termed anergy. Broad repertoire autoreactivity may reflect the chances of generating autoreactivity by stochastic use of germline immunoglobulin gene segments or active mechanisms may select autoreactive cells during egress to the naïve peripheral B cell pool. Likewise, it is unclear why in some individuals autoreactive B cell clones become activated and drive pathophysiologic changes in autoimmune diseases. Both of these remain central questions in the study of the immune system(s). In most individuals, autoimmune diseases arise from complex interplay of genetic risk factors and environmental influences. Advances in genome sequencing and increased statistical power from large autoimmune disease cohorts has led to identification of more than 200 autoimmune disease risk loci. It has been observed that autoantibodies are detectable in the serum years to decades prior to the diagnosis of autoimmune disease. Thus, current models hold that genetic defects in the pathways that control autoreactive B cell tolerance set genetic liability thresholds across multiple autoimmune diseases. Despite the fact these seminal concepts were developed in animal (especially murine) models of autoimmune disease, some perceive a disconnect between human risk alleles and those identified in murine models of autoimmune disease. Here, we synthesize the current state of the art in our understanding of human risk alleles in two prototypical autoimmune diseases – systemic lupus erythematosus (SLE) and type 1 diabetes (T1D) along with spontaneous murine disease models. We compare these risk networks to those reported in murine models of these diseases, focusing on pathways relevant to anergy and central tolerance. We highlight some differences between murine and human environmental and genetic factors that may impact autoimmune disease development and expression and may, in turn, explain some of this discrepancy. Finally, we show that there is substantial overlap between the molecular networks that define these disease states across species. Our synthesis and analysis of the current state of the field are consistent with the idea that the same molecular networks are perturbed in murine and human autoimmune disease. Based on these analyses, we anticipate that murine autoimmune disease models will continue to yield novel insights into how best to diagnose, prognose, prevent and treat human autoimmune diseases.
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Affiliation(s)
- Isaac T. W. Harley
- Division of Rheumatology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Human Immunology and Immunotherapy Initiative (HI3), Department of Immunology, University of Colorado School of Medicine, Aurora, CO, United States
- Rheumatology Section, Medicine Service, Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States
- *Correspondence: Isaac T. W. Harley,
| | - Kristen Allison
- Division of Rheumatology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Human Immunology and Immunotherapy Initiative (HI3), Department of Immunology, University of Colorado School of Medicine, Aurora, CO, United States
| | - R. Hal Scofield
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Arthritis & Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
- Medical/Research Service, US Department of Veterans Affairs Medical Center, Oklahoma City, OK, United States
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3
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Fernández-Medarde A, Santos E. Ras GEF Mouse Models for the Analysis of Ras Biology and Signaling. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:361-395. [PMID: 33977490 DOI: 10.1007/978-1-0716-1190-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Animal models have become in recent years a crucial tool to understand the physiological and pathological roles of many cellular proteins. They allow analysis of the functional consequences of [1] complete or partial (time- or organ-limited) removal of specific proteins (knockout animals), [2] the exchange of a wild-type allele for a mutant or truncated version found in human illnesses (knock-in), or [3] the effect of overexpression of a given protein in the whole body or in specific organs (transgenic mice). In this regard, the study of phenotypes in Ras GEF animal models has allowed researchers to find specific functions for otherwise very similar proteins, uncovering their role in physiological contexts such as memory formation, lymphopoiesis, photoreception, or body homeostasis. In addition, mouse models have been used to unveil the functional role of Ras GEFs under pathological conditions, including Noonan syndrome, skin tumorigenesis, inflammatory diseases, diabetes, or ischemia among others. In the following sections, we will describe the methodological approaches employed for Ras GEF animal model analyses, as well as the main discoveries made.
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Affiliation(s)
- Alberto Fernández-Medarde
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain.
| | - Eugenio Santos
- Centro de Investigación del Cáncer-Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca) and CIBERONC, Salamanca, Spain
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4
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Mahajan VS, Mattoo H, Sun N, Viswanadham V, Yuen GJ, Allard-Chamard H, Ahmad M, Murphy SJH, Cariappa A, Tuncay Y, Pillai S. B1a and B2 cells are characterized by distinct CpG modification states at DNMT3A-maintained enhancers. Nat Commun 2021; 12:2208. [PMID: 33850140 PMCID: PMC8044213 DOI: 10.1038/s41467-021-22458-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 03/07/2021] [Indexed: 01/29/2023] Open
Abstract
The B1 and B2 lineages of B cells contribute to protection from pathogens in distinct ways. The role of the DNA CpG methylome in specifying these two B-cell fates is still unclear. Here we profile the CpG modifications and transcriptomes of peritoneal B1a and follicular B2 cells, as well as their respective proB cell precursors in the fetal liver and adult bone marrow from wild-type and CD19-Cre Dnmt3a floxed mice lacking DNMT3A in the B lineage. We show that an underlying foundational CpG methylome is stably established during B lineage commitment and is overlaid with a DNMT3A-maintained dynamic methylome that is sculpted in distinct ways in B1a and B2 cells. This dynamic DNMT3A-maintained methylome is composed of novel enhancers that are closely linked to lineage-specific genes. While DNMT3A maintains the methylation state of these enhancers in both B1a and B2 cells, the dynamic methylome undergoes a prominent programmed demethylation event during B1a but not B2 cell development. We propose that the methylation pattern of DNMT3A-maintained enhancers is determined by the coincident recruitment of DNMT3A and TET enzymes, which regulate the developmental expression of B1a and B2 lineage-specific genes.
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Affiliation(s)
- Vinay S Mahajan
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Brigham and Women's Hospital, Boston, MA, USA
| | - Hamid Mattoo
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Immunology and Inflammation Therapeutic Area, Sanofi, Cambridge, MA, USA
| | - Na Sun
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Department of Electrical Engineering and Computer Science, MIT, Cambridge, MA, USA
| | - Vinayak Viswanadham
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Grace J Yuen
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | | | - Maimuna Ahmad
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | | | | | - Yesim Tuncay
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Shiv Pillai
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA.
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5
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Bajad P, Ebner F, Amman F, Szabó B, Kapoor U, Manjali G, Hildebrandt A, Janisiw MP, Jantsch MF. An internal deletion of ADAR rescued by MAVS deficiency leads to a minute phenotype. Nucleic Acids Res 2020; 48:3286-3303. [PMID: 31956894 PMCID: PMC7102943 DOI: 10.1093/nar/gkaa025] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 12/27/2019] [Accepted: 01/16/2020] [Indexed: 12/22/2022] Open
Abstract
The RNA-editing protein ADAR is essential for early development in the mouse. Genetic evidence suggests that A to I editing marks endogenous RNAs as ‘self’. Today, different Adar knockout alleles have been generated that show a common phenotype of apoptosis, liver disintegration, elevated immune response and lethality at E12.5. All the Adar knockout alleles can be rescued by a concomitant deletion of the innate immunity genes Mavs or Ifih1 (MDA5), albeit to different extents. This suggests multiple functions of ADAR. We analyze AdarΔ7-9 mice that show a unique growth defect phenotype when rescued by Mavs. We show that AdarΔ7-9 can form a truncated, unstable, editing deficient protein that is mislocalized. Histological and hematologic analysis of these mice indicate multiple tissue- and hematopoietic defects. Gene expression profiling shows dysregulation of Rps3a1 and Rps3a3 in rescued AdarΔ7-9. Consistently, a distortion in 40S and 60S ribosome ratios is observed in liver cells. This dysregulation is also seen in AdarΔ2-13; Mavs−/− but not in AdarE861A/E861A; Ifih1−/− mice, suggesting editing-independent functions of ADAR in regulating expression levels of Rps3a1 and Rps3a3. In conclusion, our study demonstrates the importance of ADAR in post-natal development which cannot be compensated by ADARB1.
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Affiliation(s)
- Prajakta Bajad
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Florian Ebner
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Fabian Amman
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria.,Institute of Theoretical Biochemistry, University of Vienna, Währinger Strasse 17, A-1090 Vienna, Austria
| | - Brigitta Szabó
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Utkarsh Kapoor
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Greeshma Manjali
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Alwine Hildebrandt
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Michael P Janisiw
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
| | - Michael F Jantsch
- Department of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria
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Abstract
Nonclonal innate immune responses mediated by germ line-encoded receptors, such as Toll-like receptors or natural killer receptors, are commonly contrasted with diverse, clonotypic adaptive responses of lymphocyte antigen receptors generated by somatic recombination. However, the Variable (V) regions of antigen receptors include germ line-encoded motifs unaltered by somatic recombination, and theoretically available to mediate nonclonal, innate responses, that are independent of or largely override clonotypic responses. Recent evidence demonstrates that such responses exist, underpinning the associations of particular γδ T cell receptors (TCRs) with specific anatomical sites. Thus, TCRγδ can make innate and adaptive responses with distinct functional outcomes. Given that αβ T cells and B cells can also make nonclonal responses, we consider that innate responses of antigen receptor V-regions may be more widespread, for example, inducing states of preparedness from which adaptive clones are better selected. We likewise consider that potent, nonclonal T cell responses to microbial superantigens may reflect subversion of physiologic innate responses of TCRα/β chains.
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Affiliation(s)
- Adrian C Hayday
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Pierre Vantourout
- Peter Gorer Department of Immunobiology, King's College, London, SE1 9RT, United Kingdom; .,Immunosurveillance Laboratory, Francis Crick Institute, London, NW1 1AT, United Kingdom
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7
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Upadhye A, Sturek JM, McNamara CA. 2019 Russell Ross Memorial Lecture in Vascular Biology: B Lymphocyte-Mediated Protective Immunity in Atherosclerosis. Arterioscler Thromb Vasc Biol 2019; 40:309-322. [PMID: 31852222 DOI: 10.1161/atvbaha.119.313064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Atherosclerosis-the major underlying pathology of cardiovascular disease-is characterized by accumulation and subsequent oxidative modification of lipoproteins within the artery wall, leading to inflammatory cell infiltration and lesion formation that can over time result in arterial stenosis, ischemia, and downstream adverse events. The contribution of innate and adaptive immunity to atherosclerosis development is well established, and B cells have emerged as important modulators of both pro- and anti-inflammatory effects in atherosclerosis. Murine B cells can broadly be divided into 2 subsets: (1) B-2 cells, which are bone marrow derived and include conventional follicular and marginal zone B cells, and (2) B-1 cells, which are largely fetal liver derived and persist in adults through self-renewal. B-cell subsets are developmentally, functionally, and phenotypically distinct with unique subset-specific contributions to atherosclerosis development. Mechanisms whereby B cells regulate vascular inflammation and atherosclerosis will be discussed with a particular emphasis on B-1 cells. B-1 cells have a protective role in atherosclerosis that is mediated in large part by IgM antibody production. Accumulating evidence over the last several years has pointed to a previously underappreciated heterogeneity in B-1 cell populations, which may have important implications for understanding atherosclerosis development and potential targeted therapeutic approaches. This heterogeneity within atheroprotective innate B-cell subsets will be highlighted.
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Affiliation(s)
- Aditi Upadhye
- From the Robert M. Berne Cardiovascular Research Center (A.U., C.A.M.), University of Virginia School of Medicine, Charlottesville
| | - Jeffrey M Sturek
- Division of Pulmonary and Critical Care Medicine, Department of Medicine (J.M.S.), University of Virginia School of Medicine, Charlottesville
| | - Coleen A McNamara
- From the Robert M. Berne Cardiovascular Research Center (A.U., C.A.M.), University of Virginia School of Medicine, Charlottesville.,Division of Cardiovascular Medicine (C.A.M.), University of Virginia School of Medicine, Charlottesville
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8
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Guo B, Ludlow AV, Brightwell AS, Rothstein TL. Impairment of PD-L2 positive B1a cells enhances susceptibility to sepsis in RasGRP1-deficient mice. Cell Immunol 2019; 346:103993. [PMID: 31679751 DOI: 10.1016/j.cellimm.2019.103993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 12/20/2022]
Abstract
RasGRP1 is a key molecule that mediates antigen-initiated signaling for activation of the RAS-MAPK pathway in lymphocytes. Patients with aberrant RasGRP1 expression experience lymphocyte dysfunction and are afflicted with recurrent microbial infections. Yet, the underlying mechanism that accounts for microbial infection remains unknown. We previously reported that B1a cells are heterogeneous with respect to PD-L2 expression and that RasGRP1 deficiency preferentially impairs PD-L2+ B1a cell development. In the present study, we show that PD-L2+ B1a cells exhibit increased capacity for differentiation to CD138+ plasma cells that secrete natural IgM antibody, as well as IL-10 and GM-CSF, in response to TLR stimulation. In keeping with this, we show here that RasGRP1-deficent mice are much more susceptible to septic infection triggered by cecalligation and puncture than wild type mice, and that reconstitution of RasGRP1-deficient mice with wild type PD-L2+ B1a cells greatly rescues RasGRP1-deficient mice from sepsis. Thus, this study indicates a mechanism for the association of RasGRP1 deficiency with predispostion to infection in the loss of a particular B1a subpopulation.
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Affiliation(s)
- Benchang Guo
- Center for Immunobiology, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA.
| | - Alexander V Ludlow
- Center for Immunobiology, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
| | - Angela S Brightwell
- Center for Immunobiology, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
| | - Thomas L Rothstein
- Center for Immunobiology, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA; Department of Biomedical Sciences, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI, USA
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9
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Molineros JE, Singh B, Terao C, Okada Y, Kaplan J, McDaniel B, Akizuki S, Sun C, Webb CF, Looger LL, Nath SK. Mechanistic Characterization of RASGRP1 Variants Identifies an hnRNP-K-Regulated Transcriptional Enhancer Contributing to SLE Susceptibility. Front Immunol 2019; 10:1066. [PMID: 31164884 PMCID: PMC6536009 DOI: 10.3389/fimmu.2019.01066] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/25/2019] [Indexed: 11/21/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease with a strong genetic component. We recently identified a novel SLE susceptibility locus near RASGRP1, which governs the ERK/MAPK kinase cascade and B-/T-cell differentiation and development. However, precise causal RASGRP1 functional variant(s) and their mechanisms of action in SLE pathogenesis remain undefined. Our goal was to fine-map this locus, prioritize genetic variants likely to be functional, experimentally validate their biochemical mechanisms, and determine the contribution of these SNPs to SLE risk. We performed a meta-analysis across six Asian and European cohorts (9,529 cases; 22,462 controls), followed by in silico bioinformatic and epigenetic analyses to prioritize potentially functional SNPs. We experimentally validated the functional significance and mechanism of action of three SNPs in cultured T-cells. Meta-analysis identified 18 genome-wide significant (p < 5 × 10−8) SNPs, mostly concentrated in two haplotype blocks, one intronic and the other intergenic. Epigenetic fine-mapping, allelic, eQTL, and imbalance analyses predicted three transcriptional regulatory regions with four SNPs (rs7170151, rs11631591-rs7173565, and rs9920715) prioritized for functional validation. Luciferase reporter assays indicated significant allele-specific enhancer activity for intronic rs7170151 and rs11631591-rs7173565 in T-lymphoid (Jurkat) cells, but not in HEK293 cells. Following up with EMSA, mass spectrometry, and ChIP-qPCR, we detected allele-dependent interactions between heterogeneous nuclear ribonucleoprotein K (hnRNP-K) and rs11631591. Furthermore, inhibition of hnRNP-K in Jurkat and primary T-cells downregulated RASGRP1 and ERK/MAPK signaling. Comprehensive association, bioinformatics, and epigenetic analyses yielded putative functional variants of RASGRP1, which were experimentally validated. Notably, intronic variant (rs11631591) is located in a cell type-specific enhancer sequence, where its risk allele binds to the hnRNP-K protein and modulates RASGRP1 expression in Jurkat and primary T-cells. As risk allele dosage of rs11631591 correlates with increased RASGRP1 expression and ERK activity, we suggest that this SNP may underlie SLE risk at this locus.
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Affiliation(s)
- Julio E Molineros
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Bhupinder Singh
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Chikashi Terao
- Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukinori Okada
- Department of Statistical Genetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jakub Kaplan
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Barbara McDaniel
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Shuji Akizuki
- Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Celi Sun
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Carol F Webb
- Departments of Medicine, Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma, OK, United States
| | - Loren L Looger
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, United States
| | - Swapan K Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
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10
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Pal Singh S, de Bruijn MJW, de Almeida MP, Meijers RWJ, Nitschke L, Langerak AW, Pillai SY, Stadhouders R, Hendriks RW. Identification of Distinct Unmutated Chronic Lymphocytic Leukemia Subsets in Mice Based on Their T Cell Dependency. Front Immunol 2018; 9:1996. [PMID: 30271400 PMCID: PMC6146083 DOI: 10.3389/fimmu.2018.01996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/14/2018] [Indexed: 01/27/2023] Open
Abstract
Chronic lymphocytic leukemia (CLL) can be divided into prognostically distinct subsets with stereotyped or non-stereotyped, mutated or unmutated B cell receptors (BCRs). Individual subsets vary in antigen specificity and origin, but the impact of antigenic pressure on the CLL BCR repertoire remains unknown. Here, we employed IgH.TEμ mice that spontaneously develop CLL, expressing mostly unmutated BCRs of which ~35% harbor VH11-2/Vκ14-126 and recognize phosphatidylcholine. Proportions of VH11/Vκ14-expressing CLL were increased in the absence of functional germinal centers in IgH.TEμ mice deficient for CD40L or activation-induced cytidine deaminase. Conversely, in vivo T cell-dependent immunization decreased the proportions of VH11/Vκ14-expressing CLL. Furthermore, CLL onset was accelerated by enhanced BCR signaling in Siglec-G−/− mice or in mice expressing constitutively active Bruton's tyrosine kinase. Transcriptional profiling revealed that VH11 and non-VH11 CLL differed in the upregulation of specific pathways implicated in cell signaling and metabolism. Interestingly, principal component analyses using the 148 differentially expressed genes revealed that VH11 and non-VH11 CLL clustered with BCR-stimulated and anti-CD40-stimulated B cells, respectively. We identified an expression signature consisting of 13 genes that were differentially expressed in a larger panel of T cell-dependent non-VH11 CLL compared with T cell-independent VH11/Vκ14 or mutated IgH.TEμ CLL. Parallel differences in the expression of these 13 signature genes were observed between heterogeneous and stereotypic human unmutated CLL. Our findings provide evidence for two distinct unmutated CLL subsets with a specific transcriptional signature: one is T cell-independent and B-1 cell-derived while the other arises upon antigen stimulation in the context of T-cell help.
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Affiliation(s)
- Simar Pal Singh
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, Netherlands.,Department of Immunology, Erasmus MC, Rotterdam, Netherlands.,Post-graduate School Molecular Medicine, Erasmus MC, Rotterdam, Netherlands
| | | | | | | | - Lars Nitschke
- Department of Genetics, University of Erlangen, Erlangen, Germany
| | | | | | - Ralph Stadhouders
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, Netherlands.,Department of Cell Biology, Erasmus MC, Rotterdam, Netherlands
| | - Rudi W Hendriks
- Department of Pulmonary Medicine, Erasmus MC, Rotterdam, Netherlands
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11
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Vanshylla K, Bartsch C, Hitzing C, Krümpelmann L, Wienands J, Engels N. Grb2 and GRAP connect the B cell antigen receptor to Erk MAP kinase activation in human B cells. Sci Rep 2018; 8:4244. [PMID: 29523808 PMCID: PMC5844867 DOI: 10.1038/s41598-018-22544-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/19/2018] [Indexed: 11/09/2022] Open
Abstract
The B cell antigen receptor (BCR) employs enzymatically inactive adaptor proteins to facilitate activation of intracellular signaling pathways. In animal model systems, adaptor proteins of the growth factor receptor-bound 2 (Grb2) family have been shown to serve critical functions in lymphocytes. However, the roles of Grb2 and the Grb2-related adaptor protein (GRAP) in human B lymphocytes remain unclear. Using TALEN-mediated gene targeting, we show that in human B cells Grb2 and GRAP amplify signaling by the immunoglobulin tail tyrosine (ITT) motif of mIgE-containing BCRs and furthermore connect immunoreceptor tyrosine-based activation motif (ITAM) signaling to activation of the Ras-controlled Erk MAP kinase pathway. In contrast to mouse B cells, BCR-induced activation of Erk in human B cells is largely independent of phospholipase C-ɣ activity and diacylglycerol-responsive members of Ras guanine nucleotide releasing proteins. Together, our results demonstrate that Grb2 family adaptors are critical regulators of ITAM and ITT signaling in naïve and IgE-switched human B cells.
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Affiliation(s)
- Kanika Vanshylla
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Caren Bartsch
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Christoffer Hitzing
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Laura Krümpelmann
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Jürgen Wienands
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany
| | - Niklas Engels
- University Medical Center Goettingen, Institute of Cellular & Molecular Immunology, Humboldtallee 34, 37073, Goettingen, Germany.
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12
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Winter S, Martin E, Boutboul D, Lenoir C, Boudjemaa S, Petit A, Picard C, Fischer A, Leverger G, Latour S. Loss of RASGRP1 in humans impairs T-cell expansion leading to Epstein-Barr virus susceptibility. EMBO Mol Med 2018; 10:188-199. [PMID: 29282224 PMCID: PMC5801500 DOI: 10.15252/emmm.201708292] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 12/15/2022] Open
Abstract
Inherited CTPS1, CD27, and CD70 deficiencies in humans have revealed key factors of T-lymphocyte expansion, a critical prerequisite for an efficient immunity to Epstein-Barr virus (EBV) infection. RASGRP1 is a T-lymphocyte-specific nucleotide exchange factor known to activate the pathway of MAP kinases (MAPK). A deleterious homozygous mutation in RASGRP1 leading to the loss RASGRP1 expression was identified in two siblings who both developed a persistent EBV infection leading to Hodgkin lymphoma. RASGRP1-deficient T cells exhibited defective MAPK activation and impaired proliferation that was restored by expression of wild-type RASGRP1. Similar defects were observed in T cells from healthy individuals when RASGRP1 was downregulated. RASGRP1-deficient T cells also exhibited decreased CD27-dependent proliferation toward CD70-expressing EBV-transformed B cells, a crucial pathway required for expansion of antigen-specific T cells during anti-EBV immunity. Furthermore, RASGRP1-deficient T cells failed to upregulate CTPS1, an important enzyme involved in DNA synthesis. These results show that RASGRP1 deficiency leads to susceptibility to EBV infection and demonstrate the key role of RASGRP1 at the crossroad of pathways required for the expansion of activated T lymphocytes.
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Affiliation(s)
- Sarah Winter
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
- Imagine Institut, University Paris Descartes Sorbonne Paris Cité, Paris, France
| | - Emmanuel Martin
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
| | - David Boutboul
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
| | - Christelle Lenoir
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
| | - Sabah Boudjemaa
- Department of Pathology, Armand Trousseau Hospital, Paris, France
| | - Arnaud Petit
- Department of Hematology and Pediatric Oncology, Armand Trousseau Hospital, Paris, France
| | - Capucine Picard
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
- Imagine Institut, University Paris Descartes Sorbonne Paris Cité, Paris, France
- Centre d'Etude des Déficits Immunitaires, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Alain Fischer
- Imagine Institut, University Paris Descartes Sorbonne Paris Cité, Paris, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
- Collège de France, Paris, France
- Inserm UMR 1163, Paris, France
| | - Guy Leverger
- Department of Hematology and Pediatric Oncology, Armand Trousseau Hospital, Paris, France
| | - Sylvain Latour
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Paris, France
- Imagine Institut, University Paris Descartes Sorbonne Paris Cité, Paris, France
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13
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King A, Li L, Wong DM, Liu R, Bamford R, Strasser A, Tarlinton DM, Heierhorst J. Dynein light chain regulates adaptive and innate B cell development by distinctive genetic mechanisms. PLoS Genet 2017; 13:e1007010. [PMID: 28922373 PMCID: PMC5619840 DOI: 10.1371/journal.pgen.1007010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 09/28/2017] [Accepted: 09/07/2017] [Indexed: 11/29/2022] Open
Abstract
Mechanistic differences in the development and function of adaptive, high-affinity antibody-producing B-2 cells and innate-like, “natural” antibody-producing B-1a cells remain poorly understood. Here we show that the multi-functional dynein light chain (DYNLL1/LC8) plays important roles in the establishment of B-1a cells in the peritoneal cavity and in the ongoing development of B-2 lymphoid cells in the bone marrow of mice. Epistasis analyses indicate that Dynll1 regulates B-1a and early B-2 cell development in a single, linear pathway with its direct transcriptional activator ASCIZ (ATMIN/ZNF822), and that the two genes also have complementary functions during late B-2 cell development. The B-2 cell defects caused by loss of DYNLL1 were associated with lower levels of the anti-apoptotic protein BCL-2, and could be supressed by deletion of pro-apoptotic BIM which is negatively regulated by both DYNLL1 and BCL-2. Defects in B cell development caused by loss of DYNLL1 could also be partially suppressed by a pre-arranged SWHELIgm-B cell receptor transgene. In contrast to the rescue of B-2 cell numbers, the B-1a cell deficiency in Dynll1-deleted mice could not be suppressed by the loss of Bim, and was further compounded by the SWHEL transgene. Conversely, oncogenic MYC expression, which is synthetic lethal with Dynll1 deletion in B-2 cells, did not further reduce B-1a cell numbers in Dynll1-defcient mice. Finally, we found that the ASCIZ-DYNLL1 axis was also required for the early-juvenile development of aggressive MYC-driven and p53-deficient B cell lymphomas. These results identify ASCIZ and DYNLL1 as the core of a transcriptional circuit that differentially regulates the development of the B-1a and B-2 B lymphoid cell lineages and plays a critical role in lymphomagenesis. Antibody-producing B cells can be segregated into two major populations: The better known conventional B-2 cells typically produce high-affinity and mono-specific antibodies, but only after they encounter a particular pathogen or in response to vaccines. In contrast, the B-1a cells constitutively produce lower-affinity broad-specificity “natural” antibodies that serve as a preemptive defense against a wide range of microbes. Here we reveal that the transcription factor ASCIZ and its target DYNLL1 are essential for mice to have a normally sized pool of B-1a cells in place shortly after birth. We show that these two factors function in a single linear pathway during the development of B-1a cells. This interaction represents a rare example where the activity of a transcription factor, in this case ASCIZ, can be explained by the effects of a single target gene, in this case Dynll1. While ASCIZ and DYNLL1 are also required for producing normal numbers of B-2 cells, we discovered that they regulate B-1a cells and B-2 cells by distinct genetic mechanisms. Finally, we found that ASCIZ also contributes to the early onset of B-1a B cell-derived lymphoid cancers in juvenile mice. The results provide insight into the development of an important cell population of the immune system.
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Affiliation(s)
- Ashleigh King
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
- Department of Medicine (St. Vincent’s Health), University of Melbourne, Fitzroy, Victoria, Australia
| | - Lingli Li
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
- Department of Medicine (St. Vincent’s Health), University of Melbourne, Fitzroy, Victoria, Australia
| | - David M. Wong
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Rui Liu
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Rebecca Bamford
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Andreas Strasser
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - David M. Tarlinton
- Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia
| | - Jörg Heierhorst
- Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
- Department of Medicine (St. Vincent’s Health), University of Melbourne, Fitzroy, Victoria, Australia
- * E-mail:
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14
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Essential role for the transcription factor Bhlhe41 in regulating the development, self-renewal and BCR repertoire of B-1a cells. Nat Immunol 2017; 18:442-455. [PMID: 28250425 PMCID: PMC5363839 DOI: 10.1038/ni.3694] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 01/26/2017] [Indexed: 01/02/2023]
Abstract
Innate-like B-1a cells provide a first line of defense against pathogens, yet little is known about their transcriptional control. Here we identified an essential role of the transcription factor Bhlhe41, with a lesser contribution of Bhlhe40, in controlling late stages of B-1a cell differentiation. Bhlhe41–/–Bhlhe40–/– B-1a cells were severely reduced as compared to their wild-type counterparts. Mutant B-1a cells exhibited an abnormal cell-surface phenotype and altered B-cell receptor (BCR) repertoire exemplified by loss of the phosphatidylcholine-specific VH12/Vκ4 BCR. Expression of a pre-rearranged VH12/Vκ4 BCR failed to rescue the mutant phenotype and revealed enhanced proliferation accompanied with increased cell death. Bhlhe41 directly repressed the expression of cell cycle regulators and inhibitors of BCR signaling, while enabling pro-survival cytokine signaling. Thus, Bhlhe41 controls the development, BCR repertoire and self-renewal of B-1a cells.
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15
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Holodick NE, Vizconde T, Hopkins TJ, Rothstein TL. Age-Related Decline in Natural IgM Function: Diversification and Selection of the B-1a Cell Pool with Age. THE JOURNAL OF IMMUNOLOGY 2016; 196:4348-57. [PMID: 27183643 DOI: 10.4049/jimmunol.1600073] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/18/2016] [Indexed: 01/21/2023]
Abstract
Streptococcus pneumoniae is the most common cause of pneumonia, which claims the lives of people over the age of 65 y seven times more frequently than those aged 5-49 y. B-1a cells provide immediate and essential protection from S. pneumoniae through production of natural Ig, which has minimal insertion of N-region additions added by the enzyme TdT. In experiments with SCID mice infected with S. pneumoniae, we found passive transfer of IgG-depleted serum from aged (18-24 mo old) mice had no effect whereas IgG-depleted serum from young (3 mo old) mice was protective. This suggests protective natural IgM changes with age. Using single cell PCR we found N-region addition, which is initially low in fetal-derived B-1a cell IgM developing in the absence of TdT, increased in 7- to 24-mo-old mice as compared with 3-mo-old mice. To determine the mechanism responsible for the age related change in B-1a cell IgM, we established a mixed chimera system in which mice were reconstituted with allotype-marked mature peritoneal B-1a cells and adult bone marrow cells. We demonstrated even in the presence of mature peritoneal B-1a cells, adult bone marrow contributed to the mature B-1a cell pool. More importantly, using this system we found over a 10-mo-period peritoneal B-1a cell IgM changed, showing the number of cells lacking N-region additions at both junctions fell from 49 to 29% of sequences. These results strongly suggest selection-induced skewing alters B-1a cell-derived natural Ab, which may in turn be responsible for the loss of natural IgM-mediated protection against pneumococcal infection.
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Affiliation(s)
- Nichol E Holodick
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Hofstra Northwell School of Medicine, Manhasset, NY 11030;
| | - Teresa Vizconde
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Hofstra Northwell School of Medicine, Manhasset, NY 11030
| | - Thomas J Hopkins
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Hofstra Northwell School of Medicine, Manhasset, NY 11030
| | - Thomas L Rothstein
- Center for Oncology and Cell Biology, Feinstein Institute for Medical Research, Hofstra Northwell School of Medicine, Manhasset, NY 11030; Department of Medicine, Hofstra Northwell School of Medicine, Manhasset, NY 11030; and Department of Molecular Medicine, Hofstra Northwell School of Medicine, Manhasset, NY 11030
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