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Fiske BE, Wemlinger SM, Crute BW, Getahun A. The Src-family kinase Lyn plays a critical role in establishing and maintaining B cell anergy by suppressing PI3K-dependent signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.595208. [PMID: 38826354 PMCID: PMC11142063 DOI: 10.1101/2024.05.21.595208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Although the Src family kinase (SFK) Lyn is known to be involved in induction and maintenance of peripheral B cell tolerance, the molecular basis of its action in this context remains unclear. This question has been approached using conventional as well as B cell-targeted knockouts of Lyn, with varied conclusions likely confused by collateral loss of Lyn functions in B cell and myeloid cell development and activation. Here we utilized a system in which Lyn gene deletion is tamoxifen inducible and B cell restricted. This system allows acute elimination of Lyn in B cells without off-target effects. This genetic tool was employed in conjunction with immunoglobulin transgenic mice in which peripheral B cells are autoreactive. DNA reactive Ars/A1 B cells require continuous inhibitory signaling, mediated by the inositol phosphatase SHIP-1 and the tyrosine phosphatase SHP-1, to maintain an unresponsive (anergic) state. Here we show that Ars/A1 B cells require Lyn to establish and maintain B cell unresponsiveness. Lyn primarily functions by restricting PI3K-dependent signaling pathways. This Lyn-dependent mechanism complements the impact of reduced mIgM BCR expression to restrict BCR signaling in Ars/A1 B cells. Our findings suggest that a subset of autoreactive B cells requires Lyn to become anergic and that the autoimmunity associated with dysregulated Lyn function may, in part, be due to an inability of these autoreactive B cells to become tolerized.
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2
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Ono C, Tanaka S, Myouzen K, Iwasaki T, Ueda M, Oda Y, Yamamoto K, Kochi Y, Baba Y. Upregulated Fcrl5 disrupts B cell anergy and causes autoimmune disease. Front Immunol 2023; 14:1276014. [PMID: 37841260 PMCID: PMC10569490 DOI: 10.3389/fimmu.2023.1276014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
B cell anergy plays a critical role in maintaining self-tolerance by inhibiting autoreactive B cell activation to prevent autoimmune diseases. Here, we demonstrated that Fc receptor-like 5 (Fcrl5) upregulation contributes to autoimmune disease pathogenesis by disrupting B cell anergy. Fcrl5-a gene whose homologs are associated with human autoimmune diseases-is highly expressed in age/autoimmunity-associated B cells (ABCs), an autoreactive B cell subset. By generating B cell-specific Fcrl5 transgenic mice, we demonstrated that Fcrl5 overexpression in B cells caused systemic autoimmunity with age. Additionally, Fcrl5 upregulation in B cells exacerbated the systemic lupus erythematosus-like disease model. Furthermore, an increase in Fcrl5 expression broke B cell anergy and facilitated toll-like receptor signaling. Thus, Fcrl5 is a potential regulator of B cell-mediated autoimmunity by regulating B cell anergy. This study provides important insights into the role of Fcrl5 in breaking B cell anergy and its effect on the pathogenesis of autoimmune diseases.
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Affiliation(s)
- Chisato Ono
- Division of Immunology and Genome Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Shinya Tanaka
- Division of Immunology and Genome Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Keiko Myouzen
- Laboratory for Autoimmune Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Takeshi Iwasaki
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Mahoko Ueda
- Department of Genomic Function and Diversity, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshinao Oda
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhiko Yamamoto
- Laboratory for Autoimmune Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Yuta Kochi
- Department of Genomic Function and Diversity, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshihiro Baba
- Division of Immunology and Genome Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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3
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Ye Z, Wang Y, Xiang B, Wang H, Tao H, Zhang C, Zhang S, Sun D, Luo F, Song L. Roles of the Siglec family in bone and bone homeostasis. Biomed Pharmacother 2023; 165:115064. [PMID: 37413904 DOI: 10.1016/j.biopha.2023.115064] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/23/2023] [Accepted: 06/23/2023] [Indexed: 07/08/2023] Open
Abstract
Tremendous progress has been seen in the study of the role of sialic acid binding im-munoglobulin type lectins (Siglecs) in osteoimmunology in the past two decades. Interest in Siglecs as immune checkpoints has grown from the recognition that Siglecs have relevance to human disease. Siglecs play important roles in inflammation and cancer, and play key roles in immune cell signaling. By recognizing common sialic acid containing glycans on glycoproteins and glycolipids as regulatory receptors for immune cell signals, Siglecs are expressed on most immune cells and play important roles in normal homeostasis and self-tolerance. In this review, we describe the role that the siglec family plays in bone and bone homeostasis, including the regulation of osteoclast differentiation as well as recent advances in inflammation, cancer and osteoporosis. Particular emphasis is placed on the relevant functions of Siglecs in self-tolerance and as pattern recognition receptors in immune responses, thereby potentially providing emerging strategies for the treatment of bone related diseases.
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Affiliation(s)
- Zi Ye
- The Fourth Corps of Students of the Basic Medical College, Army Medical University, Chongqing 400037, China
| | - Yetong Wang
- The Fourth Corps of Students of the Basic Medical College, Army Medical University, Chongqing 400037, China
| | - Binqing Xiang
- Department of Surgical Anesthesia, First Affiliated Hospital, Army Medical University, Chongqing 400038, China
| | - Heng Wang
- Army Border Defense 331st Brigade, Dandong 118000, China
| | - Haiyan Tao
- Health Management Center, First Affiliated Hospital, Army Medical University, Chongqing 400038, China
| | - Chengmin Zhang
- Department of Orthopaedics, First Affiliated Hospital, Army Medical University, Chongqing 400038, China
| | - Shuai Zhang
- Department of Orthopaedics, First Affiliated Hospital, Army Medical University, Chongqing 400038, China
| | - Dong Sun
- Department of Orthopaedics, First Affiliated Hospital, Army Medical University, Chongqing 400038, China.
| | - Fei Luo
- Department of Orthopaedics, First Affiliated Hospital, Army Medical University, Chongqing 400038, China.
| | - Lei Song
- Department of Orthopaedics, First Affiliated Hospital, Army Medical University, Chongqing 400038, China.
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Venturelli V, Isenberg DA. Targeted Therapy for SLE-What Works, What Doesn't, What's Next. J Clin Med 2023; 12:jcm12093198. [PMID: 37176637 PMCID: PMC10179673 DOI: 10.3390/jcm12093198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
For many years, the failure of randomized controlled trials (RCTs) has prevented patients with systemic lupus erythematosus (SLE) from benefiting from biological drugs that have proved to be effective in other rheumatological diseases. Only two biologics are approved for SLE, however they can only be administered to a restricted proportion of patients. Recently, several phase II RCTs have evaluated the efficacy and safety of new biologics in extra-renal SLE and lupus nephritis. Six drug trials have reported encouraging results, with an improvement in multiple clinical and serological outcome measures. The possibility of combining B-cell depletion and anti-BLyS treatment has also been successfully explored.
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Affiliation(s)
- Veronica Venturelli
- Rheumatology Unit, Department of Medical Sciences, Università degli Studi di Ferrara, Azienda Ospedaliero-Universitaria S. Anna, 44124 Cona, Italy
| | - David Alan Isenberg
- Centre for Rheumatology, Department of Medicine, University College London, London WC1E 6JF, UK
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5
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Bangarh R, Khatana C, Kaur S, Sharma A, Kaushal A, Siwal SS, Tuli HS, Dhama K, Thakur VK, Saini RV, Saini AK. Aberrant protein glycosylation: Implications on diagnosis and Immunotherapy. Biotechnol Adv 2023; 66:108149. [PMID: 37030554 DOI: 10.1016/j.biotechadv.2023.108149] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 03/10/2023] [Accepted: 04/04/2023] [Indexed: 04/10/2023]
Abstract
Glycosylation-mediated post-translational modification is critical for regulating many fundamental processes like cell division, differentiation, immune response, and cell-to-cell interaction. Alterations in the N-linked or O-linked glycosylation pattern of regulatory proteins like transcription factors or cellular receptors lead to many diseases, including cancer. These alterations give rise to micro- and macro-heterogeneity in tumor cells. Here, we review the role of O- and N-linked glycosylation and its regulatory function in autoimmunity and aberrant glycosylation in cancer. The change in cellular glycome could result from a change in the expression of glycosidases or glycosyltransferases like N-acetyl-glucosaminyl transferase V, FUT8, ST6Gal-I, DPAGT1, etc., impact the glycosylation of target proteins leading to transformation. Moreover, the mutations in glycogenes affect glycosylation patterns on immune cells leading to other related manifestations like pro- or anti-inflammatory effects. In recent years, understanding the glycome to cancer indicates that it can be utilized for both diagnosis/prognosis as well as immunotherapy. Studies involving mass spectrometry of proteome, site- and structure-specific glycoproteomics, or transcriptomics/genomics of patient samples and cancer models revealed the importance of glycosylation homeostasis in cancer biology. The development of emerging technologies, such as the lectin microarray, has facilitated research on the structure and function of glycans and glycosylation. Newly developed devices allow for high-throughput, high-speed, and precise research on aberrant glycosylation. This paper also discusses emerging technologies and clinical applications of glycosylation.
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Affiliation(s)
- Rashmi Bangarh
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Chainika Khatana
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Simranjeet Kaur
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Anchita Sharma
- Division of Biology, Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh 517641, India
| | - Ankur Kaushal
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Samarjeet Singh Siwal
- Department of Chemistry, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Hardeep Singh Tuli
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly 243122, Uttar Pradesh, India
| | - Vijay Kumar Thakur
- Biorefining and Advanced Materials Research Center, Scotland's Rural College (SRUC), Kings Buildings, West Mains Road, Edinburgh EH9 3JG, United Kingdom; School of Engineering, University of Petroleum & Energy Studies (UPES), Dehradun 248007, Uttarakhand, India.
| | - Reena V Saini
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
| | - Adesh K Saini
- Department of Biotechnology, MMEC, Maharishi Markandeshwar (Deemed to Be University), Mullana-Ambala, Haryana 133207, India
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6
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Brzezicka KA, Paulson JC. Impact of Siglecs on autoimmune diseases. Mol Aspects Med 2023; 90:101140. [PMID: 36055802 PMCID: PMC9905255 DOI: 10.1016/j.mam.2022.101140] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 02/08/2023]
Abstract
Autoimmune diseases affect tens of millions of people just in the United States alone. Most of the available treatment options are aimed at reducing symptoms but do not lead to cures. Individuals affected with autoimmune diseases suffer from the imbalance between tolerogenic and immunogenic functions of their immune system. Often pathogenesis is mediated by autoreactive B and T cells that escape central tolerance and react against self-antigens attacking healthy tissues in the body. In recent years Siglecs, sialic-acid-binding immunoglobulin (Ig)-like lectins, have gained attention as immune checkpoints for therapeutic interventions to dampen excessive immune responses and to restore immune tolerance in autoimmune diseases. Many Siglecs function as inhibitory receptors suppressing activation signals in various immune cells through binding to sialic acid ligands as signatures of self. In this review, we highlight potential of Siglecs in suppressing immune responses causing autoimmune diseases. In particular, we cover the roles of CD22 and Siglec-G/Siglec-10 in regulating autoreactive B cell responses. We discuss several functions of Siglec-10 in the immune modulation of other immune cells, and the potential of therapeutic strategies for restoring immune tolerance by targeting Siglecs and expanding regulatory T cells. Finally, we briefly review efforts evaluating Siglec-based biomarkers to monitor autoimmune diseases.
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Affiliation(s)
- Katarzyna Alicja Brzezicka
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - James C Paulson
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
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7
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Shivatare SS, Shivatare VS, Wong CH. Glycoconjugates: Synthesis, Functional Studies, and Therapeutic Developments. Chem Rev 2022; 122:15603-15671. [PMID: 36174107 PMCID: PMC9674437 DOI: 10.1021/acs.chemrev.1c01032] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glycoconjugates are major constituents of mammalian cells that are formed via covalent conjugation of carbohydrates to other biomolecules like proteins and lipids and often expressed on the cell surfaces. Among the three major classes of glycoconjugates, proteoglycans and glycoproteins contain glycans linked to the protein backbone via amino acid residues such as Asn for N-linked glycans and Ser/Thr for O-linked glycans. In glycolipids, glycans are linked to a lipid component such as glycerol, polyisoprenyl pyrophosphate, fatty acid ester, or sphingolipid. Recently, glycoconjugates have become better structurally defined and biosynthetically understood, especially those associated with human diseases, and are accessible to new drug, diagnostic, and therapeutic developments. This review describes the status and new advances in the biological study and therapeutic applications of natural and synthetic glycoconjugates, including proteoglycans, glycoproteins, and glycolipids. The scope, limitations, and novel methodologies in the synthesis and clinical development of glycoconjugates including vaccines, glyco-remodeled antibodies, glycan-based adjuvants, glycan-specific receptor-mediated drug delivery platforms, etc., and their future prospectus are discussed.
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Affiliation(s)
- Sachin S Shivatare
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Vidya S Shivatare
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Chi-Huey Wong
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
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8
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Radovani B, Gudelj I. N-Glycosylation and Inflammation; the Not-So-Sweet Relation. Front Immunol 2022; 13:893365. [PMID: 35833138 PMCID: PMC9272703 DOI: 10.3389/fimmu.2022.893365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/30/2022] [Indexed: 12/28/2022] Open
Abstract
Chronic inflammation is the main feature of many long-term inflammatory diseases such as autoimmune diseases, metabolic disorders, and cancer. There is a growing number of studies in which alterations of N-glycosylation have been observed in many pathophysiological conditions, yet studies of the underlying mechanisms that precede N-glycome changes are still sparse. Proinflammatory cytokines have been shown to alter the substrate synthesis pathways as well as the expression of glycosyltransferases required for the biosynthesis of N-glycans. The resulting N-glycosylation changes can further contribute to disease pathogenesis through modulation of various aspects of immune cell processes, including those relevant to pathogen recognition and fine-tuning the inflammatory response. This review summarizes our current knowledge of inflammation-induced N-glycosylation changes, with a particular focus on specific subsets of immune cells of innate and adaptive immunity and how these changes affect their effector functions, cell interactions, and signal transduction.
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Affiliation(s)
- Barbara Radovani
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
| | - Ivan Gudelj
- Department of Biotechnology, University of Rijeka, Rijeka, Croatia
- Genos Glycoscience Research Laboratory, Zagreb, Croatia
- *Correspondence: Ivan Gudelj,
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9
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Wang Y, Pan P, Khan A, Çil Ç, Pineda MA. Synovial Fibroblast Sialylation Regulates Cell Migration and Activation of Inflammatory Pathways in Arthritogenesis. Front Immunol 2022; 13:847581. [PMID: 35371069 PMCID: PMC8971784 DOI: 10.3389/fimmu.2022.847581] [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: 01/03/2022] [Accepted: 02/28/2022] [Indexed: 12/30/2022] Open
Abstract
Synovial fibroblasts have emerged as critical underlying factors to perpetuate chronic joint inflammation in Rheumatoid Arthritis. Like any other cell, synovial fibroblasts are covered with a complex layer of glycans that can change in response to extracellular signals, such as inflammation. We have previously shown that inflammatory synovial fibroblasts show decreased levels of sialic acid, but our understanding of sialic acid-dependent pathophysiological pathways in these stromal cells is still very limited. In this report, we used in vivo and in vitro studies with exogenous sialidases and RNA sequencing to investigate the responses of murine synovial fibroblasts upon desialylation. Our results show that hyposialylated fibroblasts present a dysregulated migratory ability and an activated phenotype characterized by the expression of inflammatory mediators, such as cytokines and chemokines, and anti-viral related mechanisms. Removal of surface sialic acid also affected the expression of sialyltransferases, revealing the existence of a positive feedback to sustain reduced sialylation. Moreover, we demonstrate that synovial fibroblasts subsets have distinct sialyltransferase expression profiles, both in healthy and arthritic mice. These findings underline the ability of sialic acid to modulate homeostatic and inflammatory responses in non-immune synovial fibroblasts, suggesting that sialylation plays a key role in perpetuating local inflammation in the arthritic joint.
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Affiliation(s)
- Yilin Wang
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Piaopiao Pan
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Aneesah Khan
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Çağlar Çil
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Miguel A. Pineda
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom,Research Into Inflammatory Arthritis Centre Versus Arthritis (RACE), Glasgow, United Kingdom,*Correspondence: Miguel A. Pineda,
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10
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Getahun A. Role of inhibitory signaling in peripheral B cell tolerance*. Immunol Rev 2022; 307:27-42. [PMID: 35128676 PMCID: PMC8986582 DOI: 10.1111/imr.13070] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 12/16/2022]
Abstract
At least 20% of B cells in the periphery expresses an antigen receptor with a degree of self-reactivity. If activated, these autoreactive B cells pose a risk as they can contribute to the development of autoimmune diseases. To prevent their activation, both B cell-intrinsic and extrinsic tolerance mechanisms are in place in healthy individuals. In this review article, I will focus on B cell-intrinsic mechanisms that prevent the activation of autoreactive B cells in the periphery. I will discuss how inhibitory signaling circuits are established in autoreactive B cells, focusing on the Lyn-SHIP-1-SHP-1 axis, how they contribute to peripheral immune tolerance, and how disruptions of these circuits can contribute to the development of autoimmunity.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology University of Colorado SOM Aurora Colorado USA
- Department of Immunology and Genomic Medicine National Jewish Health Denver Colorado USA
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11
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Targeted Therapy for Primary Sjögren's Syndrome: Where are We Now? BioDrugs 2021; 35:593-610. [PMID: 34731460 DOI: 10.1007/s40259-021-00505-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2021] [Indexed: 10/19/2022]
Abstract
Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by dryness symptoms. This review briefly describes recent advances in the targeted therapies for pSS. Biologics evaluated for pSS treatment mainly include B cell-depleting agents, inhibitors of B cell activation, and agents that target co-signaling molecules or proinflammatory cytokines. Small molecule inhibitors that target signaling pathways have also been evaluated. However, current evidence for the efficacy of targeted therapies in pSS is still sparse. Although ianalumab (an anti-B cell-activating factor [BAFF]-receptor antibody) and iscalimab (an anti-CD40 antibody) are promising biologics for pSS, their efficacy still needs to be evaluated in larger clinical trials. For other biologics, clinical trials have found no differences versus placebo in the change from baseline in European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) score and fatigue score. Possible causes of the disappointing outcomes mainly include the inefficacy of those evaluated biologics in treating pSS, the high heterogeneous nature of pSS, irreversible exocrine glandular failure at advanced disease stages, inappropriate recruitment strategy in clinical trials, and outcome measures. Early diagnosis and glandular function-centered outcome measures may help to improve the current situation in the systemic therapy of pSS.
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12
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Ulbricht C, Leben R, Rakhymzhan A, Kirchhoff F, Nitschke L, Radbruch H, Niesner RA, Hauser AE. Intravital quantification reveals dynamic calcium concentration changes across B cell differentiation stages. eLife 2021; 10:56020. [PMID: 33749591 PMCID: PMC8060033 DOI: 10.7554/elife.56020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/19/2021] [Indexed: 01/31/2023] Open
Abstract
Calcium is a universal second messenger present in all eukaryotic cells. The mobilization and storage of Ca2+ ions drives a number of signaling-related processes, stress-responses, or metabolic changes, all of which are relevant for the development of immune cells and their adaption to pathogens. Here, we introduce the Förster resonance energy transfer (FRET)-reporter mouse YellowCaB expressing the genetically encoded calcium indicator TN-XXL in B lymphocytes. Calcium-induced conformation change of TN-XXL results in FRET-donor quenching measurable by two-photon fluorescence lifetime imaging. For the first time, using our novel numerical analysis, we extract absolute cytoplasmic calcium concentrations in activated B cells during affinity maturation in vivo. We show that calcium in activated B cells is highly dynamic and that activation introduces a persistent calcium heterogeneity to the lineage. A characterization of absolute calcium concentrations present at any time within the cytosol is therefore of great value for the understanding of long-lived beneficial immune responses and detrimental autoimmunity.
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Affiliation(s)
- Carolin Ulbricht
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Rheumatology and Clinical Immunology, Charitéplatz 1, Berlin, Germany.,Immune Dynamics, Deutsches Rheuma-Forschungszentrum Berlin, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany
| | - Ruth Leben
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany
| | - Asylkhan Rakhymzhan
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany
| | | | - Lars Nitschke
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Helena Radbruch
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Neuropathology, Charitéplatz 1, Berlin, Germany
| | - Raluca A Niesner
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany.,Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Anja E Hauser
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Rheumatology and Clinical Immunology, Charitéplatz 1, Berlin, Germany.,Immune Dynamics, Deutsches Rheuma-Forschungszentrum Berlin, ein Institut der Leibniz-Gemeinschaft, Berlin, Germany
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13
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Mathias LM, Stohl W. Systemic lupus erythematosus (SLE): emerging therapeutic targets. Expert Opin Ther Targets 2020; 24:1283-1302. [PMID: 33034541 DOI: 10.1080/14728222.2020.1832464] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a heterogeneous clinical presentation whose etiologies are multifactorial. A myriad of genetic, hormonal, immunologic, and environmental factors contribute to its pathogenesis, and its diverse biological basis and phenotypic presentations make development of therapeutics difficult. In the past decade, tens of therapeutic targets with hundreds of individual candidate therapeutics have been investigated. AREAS COVERED We used a PUBMED database search through April 2020 to review the relevant literature. This review discusses therapeutic targets in the adaptive and innate immune systems, specifically: B cell surface antigens, B cell survival factors, Bruton's tyrosine kinase, costimulators, IL-12/IL-23, the calcineurin pathway, the JAK/STAT pathway, and interferons. EXPERT OPINION Our ever-improving understanding of SLE pathophysiology in the past decade has allowed us to identify new therapeutic targets. Multiple new drugs are on the horizon that target different elements of the adaptive and innate immune systems. SLE research remains challenging due to the heterogenous clinical presentation of SLE, confounding from background immunosuppressives being taken by SLE patients, animal models that inadequately recapitulate human disease, and imperfect and complicated outcome measures. Despite these limitations, research is promising and ongoing. The search for new therapies that target specific elements of SLE pathophysiology are discussed as well as key findings, pitfalls, and questions surrounding these targets.
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Affiliation(s)
- Lauren M Mathias
- Division of Rheumatology, Department of Medicine, University of Southern California Keck School of Medicine , Los Angeles, CA, USA
| | - William Stohl
- Division of Rheumatology, Department of Medicine, University of Southern California Keck School of Medicine , Los Angeles, CA, USA
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14
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Fernandes VE, Ercoli G, Bénard A, Brandl C, Fahnenstiel H, Müller-Winkler J, Weber GF, Denny P, Nitschke L, Andrew PW. The B-cell inhibitory receptor CD22 is a major factor in host resistance to Streptococcus pneumoniae infection. PLoS Pathog 2020; 16:e1008464. [PMID: 32324805 PMCID: PMC7179836 DOI: 10.1371/journal.ppat.1008464] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 03/06/2020] [Indexed: 01/29/2023] Open
Abstract
Streptococcus pneumoniae is a major human pathogen, causing pneumonia and sepsis. Genetic components strongly influence host responses to pneumococcal infections, but the responsible loci are unknown. We have previously identified a locus on mouse chromosome 7 from a susceptible mouse strain, CBA/Ca, to be crucial for pneumococcal infection. Here we identify a responsible gene, Cd22, which carries a point mutation in the CBA/Ca strain, leading to loss of CD22 on B cells. CBA/Ca mice and gene-targeted CD22-deficient mice on a C57BL/6 background are both similarly susceptible to pneumococcal infection, as shown by bacterial replication in the lungs, high bacteremia and early death. After bacterial infections, CD22-deficient mice had strongly reduced B cell populations in the lung, including GM-CSF producing, IgM secreting innate response activator B cells, which are crucial for protection. This study provides striking evidence that CD22 is crucial for protection during invasive pneumococcal disease. Streptococcus pneumoniae (known as the pneumococcus) is a human bacterial pathogen responsible for diseases such as pneumonia and sepsis, that cause illness and death in millions of individuals. Susceptibility to pneumococcal infections is associated with genetic components that strongly influence how infected individuals respond to infection, but little is known about the causal gene(s) and the mechanisms of control of the infection. In previous studies we have found strong differences in susceptibility and resistance to pneumococcal infections between mouse strains. In this study we identified a gene, the Cd22 gene, that controls resistance to pneumococcal infection. Mice without the B-cell specific CD22 protein were much more susceptible to infection with S. pneumoniae. We could show that a protective population of B cells that migrates to the lung during pneumococcal infection is missing in Cd22-deficient mice. The study shows to a new role for CD22 and indicates a new potential target for treatment of pneumococcal infections.
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Affiliation(s)
- Vitor E. Fernandes
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- * E-mail: (VEF); (LN); (PWA)
| | - Giuseppe Ercoli
- Department of Genetics, University of Leicester, Leicester, United Kingdom
| | - Alan Bénard
- Department of Surgery, University Hospital Erlangen, Erlangen, Germany
| | - Carolin Brandl
- Division of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
| | - Hannah Fahnenstiel
- Division of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
| | | | - Georg F. Weber
- Department of Surgery, University Hospital Erlangen, Erlangen, Germany
| | - Paul Denny
- Mammalian Genetics Unit, Medical Research Council, Harwell, United Kingdom
| | - Lars Nitschke
- Division of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
- * E-mail: (VEF); (LN); (PWA)
| | - Peter W. Andrew
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
- * E-mail: (VEF); (LN); (PWA)
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15
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Abstract
The glycome describes the complete repertoire of glycoconjugates composed of carbohydrate chains, or glycans, that are covalently linked to lipid or protein molecules. Glycoconjugates are formed through a process called glycosylation and can differ in their glycan sequences, the connections between them and their length. Glycoconjugate synthesis is a dynamic process that depends on the local milieu of enzymes, sugar precursors and organelle structures as well as the cell types involved and cellular signals. Studies of rare genetic disorders that affect glycosylation first highlighted the biological importance of the glycome, and technological advances have improved our understanding of its heterogeneity and complexity. Researchers can now routinely assess how the secreted and cell-surface glycomes reflect overall cellular status in health and disease. In fact, changes in glycosylation can modulate inflammatory responses, enable viral immune escape, promote cancer cell metastasis or regulate apoptosis; the composition of the glycome also affects kidney function in health and disease. New insights into the structure and function of the glycome can now be applied to therapy development and could improve our ability to fine-tune immunological responses and inflammation, optimize the performance of therapeutic antibodies and boost immune responses to cancer. These examples illustrate the potential of the emerging field of 'glycomedicine'.
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16
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Abstract
Sialic acid-binding immunoglobulin-type lectins (Siglecs) are expressed on the majority of white blood cells of the immune system and play critical roles in immune cell signaling. Through recognition of sialic acid-containing glycans as ligands, they help the immune system distinguish between self and nonself. Because of their restricted cell type expression and roles as checkpoints in immune cell responses in human diseases such as cancer, asthma, allergy, neurodegeneration, and autoimmune diseases they have gained attention as targets for therapeutic interventions. In this review we describe the Siglec family, its roles in regulation of immune cell signaling, current efforts to define its roles in disease processes, and approaches to target Siglecs for treatment of human disease.
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Affiliation(s)
- Shiteng Duan
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
| | - James C Paulson
- Departments of Molecular Medicine, and Immunology and Microbiology, Scripps Research, La Jolla, California 92037, USA;
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17
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Enterina JR, Jung J, Macauley MS. Coordinated roles for glycans in regulating the inhibitory function of CD22 on B cells. Biomed J 2019; 42:218-232. [PMID: 31627864 PMCID: PMC6818156 DOI: 10.1016/j.bj.2019.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/19/2019] [Accepted: 07/26/2019] [Indexed: 01/17/2023] Open
Abstract
CD22 is an inhibitory B cell co-receptor that recognizes sialic acid-containing glycoconjugates as ligands. Interactions with its glycan ligands are key to regulating the ability of CD22 to modulate B cell function, the most widely explored of which is antagonizing B cell receptor (BCR) signaling. Most importantly, interactions of CD22 with ligands on the same cell (cis) control the organization of CD22 on the cell surface, which minimizes co-localization with the BCR. In contrast with the modest ability of CD22 to intrinsically dampen BCR signaling, glycan ligands presented on another cell (trans) along with an antigen drawn CD22 and the BCR together within an immunological synapse, strongly inhibiting BCR signaling. New concepts are emerging for how CD22 controls B cell function, such as changes in glycosylation at different stages of B cell differentiation, specifically on GC B cells. Related to these changes, new players, such galectin-9, have been discovered that regulate cell surface nanoclusters of CD22. Roles of glycan ligands in controlling CD22 are the primary focus of this review as we highlight the ability of CD22 to modulate B cell function.
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Affiliation(s)
- Jhon R Enterina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | - Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, Canada
| | - Matthew S Macauley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada; Department of Chemistry, University of Alberta, Edmonton, Canada.
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18
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Clark EA, Giltiay NV. CD22: A Regulator of Innate and Adaptive B Cell Responses and Autoimmunity. Front Immunol 2018; 9:2235. [PMID: 30323814 PMCID: PMC6173129 DOI: 10.3389/fimmu.2018.02235] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022] Open
Abstract
CD22 (Siglec 2) is a receptor predominantly restricted to B cells. It was initially characterized over 30 years ago and named “CD22” in 1984 at the 2nd International workshop in Boston (1). Several excellent reviews have detailed CD22 functions, CD22-regulated signaling pathways and B cell subsets regulated by CD22 or Siglec G (2–4). This review is an attempt to highlight recent and possibly forgotten findings. We also describe the role of CD22 in autoimmunity and the great potential for CD22-based immunotherapeutics for the treatment of autoimmune diseases such as systemic lupus erythematosus (SLE).
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Affiliation(s)
- Edward A Clark
- Department of Immunology, University of Washington, Seattle, WA, United States.,Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, United States
| | - Natalia V Giltiay
- Division of Rheumatology, Department of Medicine, University of Washington, Seattle, WA, United States
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19
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Özgör L, Meyer SJ, Korn M, Terörde K, Nitschke L. Sialic Acid Ligand Binding of CD22 and Siglec-G Determines Distinct B Cell Functions but Is Dispensable for B Cell Tolerance Induction. THE JOURNAL OF IMMUNOLOGY 2018; 201:2107-2116. [DOI: 10.4049/jimmunol.1800296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/27/2018] [Indexed: 12/20/2022]
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20
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Giovannone N, Liang J, Antonopoulos A, Geddes Sweeney J, King SL, Pochebit SM, Bhattacharyya N, Lee GS, Dell A, Widlund HR, Haslam SM, Dimitroff CJ. Galectin-9 suppresses B cell receptor signaling and is regulated by I-branching of N-glycans. Nat Commun 2018; 9:3287. [PMID: 30120234 PMCID: PMC6098069 DOI: 10.1038/s41467-018-05770-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 07/26/2018] [Indexed: 12/29/2022] Open
Abstract
Leukocytes are coated with a layer of heterogeneous carbohydrates (glycans) that modulate immune function, in part by governing specific interactions with glycan-binding proteins (lectins). Although nearly all membrane proteins bear glycans, the identity and function of most of these sugars on leukocytes remain unexplored. Here, we characterize the N-glycan repertoire (N-glycome) of human tonsillar B cells. We observe that naive and memory B cells express an N-glycan repertoire conferring strong binding to the immunoregulatory lectin galectin-9 (Gal-9). Germinal center B cells, by contrast, show sharply diminished binding to Gal-9 due to upregulation of I-branched N-glycans, catalyzed by the β1,6-N-acetylglucosaminyltransferase GCNT2. Functionally, we find that Gal-9 is autologously produced by naive B cells, binds CD45, suppresses calcium signaling via a Lyn-CD22-SHP-1 dependent mechanism, and blunts B cell activation. Thus, our findings suggest Gal-9 intrinsically regulates B cell activation and may differentially modulate BCR signaling at steady state and within germinal centers.
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Affiliation(s)
- N Giovannone
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - J Liang
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - A Antonopoulos
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - J Geddes Sweeney
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - S L King
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - S M Pochebit
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Pathology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - N Bhattacharyya
- Department of Surgery, Division of Otolaryngology, Brigham and Women's Hospital, Boston, MA, 02115, USA
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, USA
| | - G S Lee
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA, 02115, USA
| | - A Dell
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - H R Widlund
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - S M Haslam
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK.
| | - C J Dimitroff
- Department of Dermatology, Brigham and Women's Hospital, Boston, MA, 02115, USA.
- Harvard Medical School, Boston, MA, 02115, USA.
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21
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Melissaropoulos K, Liossis SN. Decreased CD22 expression and intracellular signaling aberrations in B cells of patients with systemic sclerosis. Rheumatol Int 2018; 38:1225-1234. [PMID: 29869007 DOI: 10.1007/s00296-018-4076-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Accepted: 06/01/2018] [Indexed: 12/18/2022]
Abstract
The objective of the study was to explore the phenotype and intracellular signaling events of B cells in patients with systemic sclerosis (SSc). Peripheral blood B cell surface markers CD19 and CD22 were evaluated by flow cytometry in 23 patients with SSc and seven healthy individuals. Levels of intracellular kinases Lyn, Syk and P-Y 348 Syk along with phosphatase SHP-1 were examined with Western immunoblotting in selected patients. P-Y 822 CD22 was subsequently evaluated flow cytometrically in antigen receptor stimulated B cells. A statistically significant decrease in CD22 B cell surface expression was found in the diffuse subset of patients (median CD22 MFI ± SD was 5.90 ± 2.35 vs 10.20 ± 1.88 for patients vs healthy controls respectively; p = 0.021), while no statistically significant change was found regarding CD19. CD22 underexpression was more pronounced when interstitial lung disease (ILD) was present (median CD22 MFI ± SD was 5.90 ± 2.25 vs 10.20 ± 1.88 for patients with ILD vs healthy controls respectively; p = 0.011). CD22 phosphorylation following B cell receptor (BCR) stimulation was also found to be impaired in patients with diffuse SSc (median change in MFI ± SD was 0.28 ± 0.09 vs 0.38 ± 0.08 for patients vs healthy controls respectively; p = 0.034). Low CD22 expression was arithmetically correlated with kinase Lyn underexpression (Pearson coefficient 0.926; p = ns) in B cells from a small sample of patients. These results suggest that CD22 underexpression and impaired phosphorylation along with implications for Lyn kinase aberrations could contribute to the activated B cell phenotype in SSc.
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Affiliation(s)
| | - Stamatis-Nick Liossis
- Division of Internal Medicine, Department of Rheumatology, Patras University Hospital, University of Patras Medical School, 26504, Patras, Greece.
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22
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Satterthwaite AB. Bruton's Tyrosine Kinase, a Component of B Cell Signaling Pathways, Has Multiple Roles in the Pathogenesis of Lupus. Front Immunol 2018; 8:1986. [PMID: 29403475 PMCID: PMC5786522 DOI: 10.3389/fimmu.2017.01986] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 12/21/2017] [Indexed: 01/08/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the loss of adaptive immune tolerance to nucleic acid-containing antigens. The resulting autoantibodies form immune complexes that promote inflammation and tissue damage. Defining the signals that drive pathogenic autoantibody production is an important step in the development of more targeted therapeutic approaches for lupus, which is currently treated primarily with non-specific immunosuppression. Here, we review the contribution of Bruton’s tyrosine kinase (Btk), a component of B and myeloid cell signaling pathways, to disease in murine lupus models. Both gain- and loss-of-function genetic studies have revealed that Btk plays multiple roles in the production of autoantibodies. These include promoting the activation, plasma cell differentiation, and class switching of autoreactive B cells. Small molecule inhibitors of Btk are effective at reducing autoantibody levels, B cell activation, and kidney damage in several lupus models. These studies suggest that Btk may promote end-organ damage both by facilitating the production of autoantibodies and by mediating the inflammatory response of myeloid cells to these immune complexes. While Btk has not been associated with SLE in GWAS studies, SLE B cells display signaling defects in components both upstream and downstream of Btk consistent with enhanced activation of Btk signaling pathways. Taken together, these observations indicate that limiting Btk activity is critical for maintaining B cell tolerance and preventing the development of autoimmune disease. Btk inhibitors, generally well-tolerated and approved to treat B cell malignancy, may thus be a useful therapeutic approach for SLE.
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Affiliation(s)
- Anne B Satterthwaite
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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23
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Chen J, Wang H, Xu WP, Wei SS, Li HJ, Mei YQ, Li YG, Wang YP. Besides an ITIM/SHP-1-dependent pathway, CD22 collaborates with Grb2 and plasma membrane calcium-ATPase in an ITIM/SHP-1-independent pathway of attenuation of Ca2+i signal in B cells. Oncotarget 2018; 7:56129-56146. [PMID: 27276708 PMCID: PMC5302901 DOI: 10.18632/oncotarget.9794] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/14/2016] [Indexed: 12/30/2022] Open
Abstract
CD22 is a surface immunoglobulin implicated in negative regulation of B cell receptor (BCR) signaling; particularly inhibiting intracellular Ca2+ (Ca2+i)signals. Its cytoplasmic tail contains six tyrosine residues (Y773/Y783/Y817/Y828/Y843/Y863, designated Y1~Y6 respectively), including three (Y2/5/6) lying within immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that serve to recruit the protein tyrosine phosphatase SHP-1 after BCR activation-induced phosphorylation. The mechanism of inhibiting Ca2+i by CD22 has been poorly understood. Previous study demonstrated that CD22 associated with plasma membrane calcium-ATPase (PMCA) and enhanced its activity (Chen, J. et al. Nat Immunol 2004;5:651-7). The association is dependent on BCR activation-induced cytoplasmic tyrosine phosphorylation, because CD22 with either all six tyrosines mutated to phenylalanines or cytoplasmic tail truncated loses its ability to associate with PMCA. However, which individual or a group of tyrosine residues determine the association and how CD22 and PMCA interacts, are still unclear. In this study, by using a series of CD22 tyrosine mutants, we found that ITIM Y2/5/6 accounts for 34.3~37.1% Ca2+i inhibition but is irrelevant for CD22/PMCA association. Non-ITIM Y4 and its YEND motif contribute to the remaining 69.4~71.7% Ca2+i inhibition and is the binding site for PMCA-associated Grb2. Grb2, independently of BCR cross-linking, is constitutively associated with and directly binds to PMCA in both chicken and human B cells. Knockout of Grb2 by CRISPR/Cas9 completely disrupted the CD22/PMCA association. Thus, our results demonstrate for the first time that in addition to previously-identified ITIM/SHP-1-dependent pathway, CD22 holds a major pathway of negative regulation of Ca2+i signal, which is ITIM/SHP-1-independent, but Y4/Grb2/PMCA-dependent.
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Affiliation(s)
- Jie Chen
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Hong Wang
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Wei-Ping Xu
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Si-Si Wei
- Department of Pediatrics, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Hui Joyce Li
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Yun-Qing Mei
- Department of Cardio-Thoracic Surgery, Shanghai Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi-Gang Li
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
| | - Yue-Peng Wang
- Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai, China
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24
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Zhang R, Verkoczy L, Wiehe K, Munir Alam S, Nicely NI, Santra S, Bradley T, Pemble CW, Zhang J, Gao F, Montefiori DC, Bouton-Verville H, Kelsoe G, Larimore K, Greenberg PD, Parks R, Foulger A, Peel JN, Luo K, Lu X, Trama AM, Vandergrift N, Tomaras GD, Kepler TB, Moody MA, Liao HX, Haynes BF. Initiation of immune tolerance-controlled HIV gp41 neutralizing B cell lineages. Sci Transl Med 2017; 8:336ra62. [PMID: 27122615 DOI: 10.1126/scitranslmed.aaf0618] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/28/2016] [Indexed: 01/09/2023]
Abstract
Development of an HIV vaccine is a global priority. A major roadblock to a vaccine is an inability to induce protective broadly neutralizing antibodies (bnAbs). HIV gp41 bnAbs have characteristics that predispose them to be controlled by tolerance. We used gp41 2F5 bnAb germline knock-in mice and macaques vaccinated with immunogens reactive with germline precursors to activate neutralizing antibodies. In germline knock-in mice, bnAb precursors were deleted, with remaining anergic B cells capable of being activated by germline-binding immunogens to make gp41-reactive immunoglobulin M (IgM). Immunized macaques made B cell clonal lineages targeted to the 2F5 bnAb epitope, but 2F5-like antibodies were either deleted or did not attain sufficient affinity for gp41-lipid complexes to achieve the neutralization potency of 2F5. Structural analysis of members of a vaccine-induced antibody lineage revealed that heavy chain complementarity-determining region 3 (HCDR3) hydrophobicity was important for neutralization. Thus, gp41 bnAbs are controlled by immune tolerance, requiring vaccination strategies to transiently circumvent tolerance controls.
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Affiliation(s)
- Ruijun Zhang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Laurent Verkoczy
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Wiehe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - S Munir Alam
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nathan I Nicely
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sampa Santra
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Todd Bradley
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Charles W Pemble
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jinsong Zhang
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Feng Gao
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - David C Montefiori
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Garnett Kelsoe
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kevin Larimore
- Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA 98109, USA
| | - Phillip D Greenberg
- Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA 98109, USA
| | - Robert Parks
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Andrew Foulger
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jessica N Peel
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kan Luo
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Xiaozhi Lu
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ashley M Trama
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nathan Vandergrift
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Thomas B Kepler
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - M Anthony Moody
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hua-Xin Liao
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Barton F Haynes
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA. Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA. Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
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25
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Taher TE, Bystrom J, Ong VH, Isenberg DA, Renaudineau Y, Abraham DJ, Mageed RA. Intracellular B Lymphocyte Signalling and the Regulation of Humoral Immunity and Autoimmunity. Clin Rev Allergy Immunol 2017; 53:237-264. [PMID: 28456914 PMCID: PMC5597704 DOI: 10.1007/s12016-017-8609-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
B lymphocytes are critical for effective immunity; they produce antibodies and cytokines, present antigens to T lymphocytes and regulate immune responses. However, because of the inherent randomness in the process of generating their vast repertoire of antigen-specific receptors, B cells can also cause diseases through recognizing and reacting to self. Therefore, B lymphocyte selection and responses require tight regulation at multiple levels and at all stages of their development and activation to avoid diseases. Indeed, newly generated B lymphocytes undergo rigorous tolerance mechanisms in the bone marrow and, subsequently, in the periphery after their migration. Furthermore, activation of mature B cells is regulated through controlled expression of co-stimulatory receptors and intracellular signalling thresholds. All these regulatory events determine whether and how B lymphocytes respond to antigens, by undergoing apoptosis or proliferation. However, defects that alter regulated co-stimulatory receptor expression or intracellular signalling thresholds can lead to diseases. For example, autoimmune diseases can result from altered regulation of B cell responses leading to the emergence of high-affinity autoreactive B cells, autoantibody production and tissue damage. The exact cause(s) of defective B cell responses in autoimmune diseases remains unknown. However, there is evidence that defects or mutations in genes that encode individual intracellular signalling proteins lead to autoimmune diseases, thus confirming that defects in intracellular pathways mediate autoimmune diseases. This review provides a synopsis of current knowledge of signalling proteins and pathways that regulate B lymphocyte responses and how defects in these could promote autoimmune diseases. Most of the evidence comes from studies of mouse models of disease and from genetically engineered mice. Some, however, also come from studying B lymphocytes from patients and from genome-wide association studies. Defining proteins and signalling pathways that underpin atypical B cell response in diseases will help in understanding disease mechanisms and provide new therapeutic avenues for precision therapy.
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Affiliation(s)
- Taher E Taher
- Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Jonas Bystrom
- Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Voon H Ong
- Centre for Rheumatology and Connective Tissue Diseases, Royal Free Hospital, University College London, London, UK
| | | | - Yves Renaudineau
- Immunology Laboratory, University of Brest Medical School, Brest, France
| | - David J Abraham
- Centre for Rheumatology and Connective Tissue Diseases, Royal Free Hospital, University College London, London, UK
| | - Rizgar A Mageed
- Centre for Experimental Medicine and Rheumatology, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
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26
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Tang H, Wang H, Lin Q, Fan F, Zhang F, Peng X, Fang X, Liu J, Ouyang K. Loss of IP3 Receptor–Mediated Ca2+ Release in Mouse B Cells Results in Abnormal B Cell Development and Function. THE JOURNAL OF IMMUNOLOGY 2017; 199:570-580. [DOI: 10.4049/jimmunol.1700109] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/17/2017] [Indexed: 12/16/2022]
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27
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Hemon P, Renaudineau Y, Debant M, Le Goux N, Mukherjee S, Brooks W, Mignen O. Calcium Signaling: From Normal B Cell Development to Tolerance Breakdown and Autoimmunity. Clin Rev Allergy Immunol 2017; 53:141-165. [DOI: 10.1007/s12016-017-8607-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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28
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Petersen F, Yue X, Riemekasten G, Yu X. Dysregulated homeostasis of target tissues or autoantigens - A novel principle in autoimmunity. Autoimmun Rev 2017; 16:602-611. [PMID: 28411168 DOI: 10.1016/j.autrev.2017.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 03/11/2017] [Indexed: 01/22/2023]
Abstract
Monogenic autoimmune disorders provide a powerful tool for our understanding of the principles of autoimmunity due to the obvious impact of a single gene on the disease. So far, approximately 100 single gene defects causing murine monogenic autoimmune disorders have been reported and the functional characterization of these genes will provide significant progress in understanding the nature of autoimmunity. According to their function, genes leading to monogenic autoimmune disorders can be categorized into two groups. An expectable first group contains genes involved in the homeostasis of the immune system, including homeostasis of immune organs and immune cells. Intriguingly, the second group consists of genes functionally involved in the homeostasis of target tissues or autoantigens. According to our novel hypothesis, we propose that autoimmunity represents a consequence of a dysregulated homeostasis of the immune system and/or its targets including autoantigens and target tissues. In this review we refer to both aspects of homeostasis in autoimmunity with a highlight on the role of the homeostasis of target tissues and autoantigens.
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Affiliation(s)
- Frank Petersen
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Members of the German Center for Lung Research (DZL), 23845 Borstel, Germany
| | - Xiaoyang Yue
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Members of the German Center for Lung Research (DZL), 23845 Borstel, Germany
| | - Gabriela Riemekasten
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Members of the German Center for Lung Research (DZL), 23845 Borstel, Germany; Department of Rheumatology, University of Lübeck, 23538 Lübeck, Germany
| | - Xinhua Yu
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), Members of the German Center for Lung Research (DZL), 23845 Borstel, Germany; Xiamen-Borstel Joint Laboratory of Autoimmunity, Medical College of Xiamen University, Xiamen 361102, China.
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29
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Abstract
Many Siglecs function as inhibitory receptors on innate and adaptive immune cells and may contribute to the attenuation of immune responses to tumors. Siglec 9 on neutrophils and Siglec 7 on NK cells are prominent examples of inhibitory Siglecs that can potentially dampen anti-tumor immunity. CD169 is a Siglec that may function as an adhesion molecule and a facilitator of the recognition and internalization of sialic acid decorated apoptotic bodies and exosomes derived from tumors. It can potentially contribute to both the attenuation as well as the facilitation of anti-tumor immunity. Siglecs have been best studied in the tumor context in animal models of cancer. Modulators of Siglec function are likely to be developed and investigated clinically in a cancer context over the next few years.
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Affiliation(s)
- Isabella Fraschilla
- Ragon Institute of MGH, MIT and Harvard, Harvard Medical School, Cambridge, MA, USA
| | - Shiv Pillai
- Ragon Institute of MGH, MIT and Harvard, Harvard Medical School, Cambridge, MA, USA
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30
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Abstract
An important underlying mechanism that contributes to autoimmunity is the loss of inhibitory signaling in the immune system. Sialic acid-recognizing Ig superfamily lectins or Siglecs are a family of cell surface proteins largely expressed in hematopoietic cells. The majority of Siglecs are inhibitory receptors expressed in immune cells that bind to sialic acid-containing ligands and recruit SH2-domain-containing tyrosine phosphatases to their cytoplasmic tails. They deliver inhibitory signals that can contribute to the constraining of immune cells, and thus protect the host from autoimmunity. The inhibitory functions of CD22/Siglec-2 and Siglec-G and their contributions to tolerance and autoimmunity, primarily in the B lymphocyte context, are considered in some detail in this review. The relevance to autoimmunity and unregulated inflammation of modified sialic acids, enzymes that modify sialic acid, and other sialic acid-binding proteins are also reviewed.
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Affiliation(s)
- Vinay S Mahajan
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.,Departments of Medicine and Pathology, Harvard Medical School, Boston, MA, USA.,Deaprtment of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Shiv Pillai
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA.,Departments of Medicine and Pathology, Harvard Medical School, Boston, MA, USA
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31
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Eakin AJ, Bustard MJ, McGeough CM, Ahmed T, Bjourson AJ, Gibson DS. Siglec-1 and -2 as potential biomarkers in autoimmune disease. Proteomics Clin Appl 2016; 10:635-44. [DOI: 10.1002/prca.201500069] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/25/2015] [Accepted: 01/05/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Amanda J. Eakin
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
| | - Michael J. Bustard
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
| | - Cathy M. McGeough
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
| | - Tahanver Ahmed
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
| | - Anthony J. Bjourson
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
| | - David S. Gibson
- Northern Ireland Centre for Stratified Medicine; Altnagelvin Hospital Campus; Ulster University; Londonderry Northern Ireland UK
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32
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Gasparrini F, Feest C, Bruckbauer A, Mattila PK, Müller J, Nitschke L, Bray D, Batista FD. Nanoscale organization and dynamics of the siglec CD22 cooperate with the cytoskeleton in restraining BCR signalling. EMBO J 2016; 35:258-80. [PMID: 26671981 PMCID: PMC4741297 DOI: 10.15252/embj.201593027] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/04/2015] [Accepted: 11/09/2015] [Indexed: 11/09/2022] Open
Abstract
Receptor organization and dynamics at the cell membrane are important factors of signal transduction regulation. Using super-resolution microscopy and single-particle tracking, we show how the negative coreceptor CD22 works with the cortical cytoskeleton in restraining BCR signalling. In naïve B cells, we found endogenous CD22 to be highly mobile and organized into nanodomains. The landscape of CD22 and its lateral diffusion were perturbed either in the absence of CD45 or when the CD22 lectin domain was mutated. To understand how a relatively low number of CD22 molecules can keep BCR signalling in check, we generated Brownian dynamic simulations and supported them with ex vivo experiments. This combined approach suggests that the inhibitory function of CD22 is influenced by its nanoscale organization and is ensured by its fast diffusion enabling a "global BCR surveillance" at the plasma membrane.
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Affiliation(s)
| | - Christoph Feest
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, London, UK
| | - Andreas Bruckbauer
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, London, UK
| | - Pieta K Mattila
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, London, UK
| | - Jennifer Müller
- Chair of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
| | - Lars Nitschke
- Chair of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
| | - Dennis Bray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Facundo D Batista
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute, London, UK
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33
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Abstract
The receptor-like tyrosine phosphatase CD45 regulates antigen receptor signaling by dephosphorylating the C-terminal inhibitory tyrosine of the src family kinases. However, despite its abundance, the function of the large, alternatively spliced extracellular domain of CD45 has remained elusive. We used normally spliced CD45 transgenes either incorporating a phosphatase-inactivating point mutation or lacking the cytoplasmic domain to uncouple the enzymatic and noncatalytic functions of CD45 in lymphocytes. Although these transgenes did not alter T-cell signaling or development irrespective of endogenous CD45 expression, both partially rescued the phenotype of CD45-deficient B cells. We identify a noncatalytic role for CD45 in regulating tonic, but not antigen-mediated, B-cell antigen receptor (BCR) signaling through modulation of the function of the inhibitory coreceptor CD22. This finding has important implications for understanding how naïve B cells maintain tonic BCR signaling while restraining inappropriate antigen-dependent activation to preserve clonal "ignorance."
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34
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Protein-carbohydrate interactions as part of plant defense and animal immunity. Molecules 2015; 20:9029-53. [PMID: 25996210 PMCID: PMC6272538 DOI: 10.3390/molecules20059029] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/12/2015] [Accepted: 05/14/2015] [Indexed: 12/20/2022] Open
Abstract
The immune system consists of a complex network of cells and molecules that interact with each other to initiate the host defense system. Many of these interactions involve specific carbohydrate structures and proteins that specifically recognize and bind them, in particular lectins. It is well established that lectin-carbohydrate interactions play a major role in the immune system, in that they mediate and regulate several interactions that are part of the immune response. Despite obvious differences between the immune system in animals and plants, there are also striking similarities. In both cases, lectins can play a role as pattern recognition receptors, recognizing the pathogens and initiating the stress response. Although plants do not possess an adaptive immune system, they are able to imprint a stress memory, a mechanism in which lectins can be involved. This review will focus on the role of lectins in the immune system of animals and plants.
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35
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Baba Y, Kurosaki T. Role of Calcium Signaling in B Cell Activation and Biology. Curr Top Microbiol Immunol 2015; 393:143-174. [PMID: 26369772 DOI: 10.1007/82_2015_477] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase in intracellular levels of calcium ions (Ca2+) is one of the key triggering signals for the development of B cell response to the antigen. The diverse Ca2+ signals finely controlled by multiple factors participate in the regulation of gene expression, B cell development, and effector functions. B cell receptor (BCR)-initiated Ca2+ mobilization is sourced from two pathways: one is the release of Ca2+ from the intracellular stores, endoplasmic reticulum (ER), and other is the prolonged influx of extracellular Ca2+ induced by depleting the stores via store-operated calcium entry (SOCE) and calcium release-activated calcium (CRAC) channels. The identification of stromal interaction molecule 1(STIM1), the ER Ca2+ sensor, and Orai1, a key subunit of the CRAC channel pore, has now provided the tools to understand the mode of Ca2+ influx regulation and physiological relevance. Herein, we discuss our current understanding of the molecular mechanisms underlying BCR-triggered Ca2+ signaling as well as its contribution to the B cell biological processes and diseases.
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Affiliation(s)
- Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan. .,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan.
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan.,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan
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36
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Daikh DI. Animal models of lupus. Rheumatology (Oxford) 2015. [DOI: 10.1016/b978-0-323-09138-1.00129-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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37
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Chance, genetics, and the heterogeneity of disease and pathogenesis in systemic lupus erythematosus. Semin Immunopathol 2014; 36:495-517. [PMID: 25102991 DOI: 10.1007/s00281-014-0440-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 06/30/2014] [Indexed: 12/30/2022]
Abstract
Systemic lupus erythematosus (SLE) is a remarkably complex and heterogeneous systemic autoimmune disease. Disease complexity within individuals and heterogeneity among individuals, even genetically identical individuals, is driven by stochastic execution of a complex inherited program. Genome-wide association studies (GWAS) have progressively improved understanding of which genes are most critical to the potential for SLE and provided illuminating insight about the immune mechanisms that are engaged in SLE. What initiates expression of the genetic program to cause SLE within an individual and how that program is initiated remains poorly understood. If we extrapolate from all of the different experimental mouse models for SLE, we can begin to appreciate why SLE is so heterogeneous and consequently why prediction of disease outcome is so difficult. In this review, we critically evaluate extrinsic versus intrinsic cellular functions in the clearance and elimination of cellular debris and how dysfunction in that system may promote autoimmunity to nuclear antigens. We also examine several mouse models genetically prone to SLE either because of natural inheritance or inheritance of induced mutations to illustrate how different immune mechanisms may initiate autoimmunity and affect disease pathogenesis. Finally, we describe the heterogeneity of disease manifestations in SLE and discuss the mechanisms of disease pathogenesis with emphasis on glomerulonephritis. Particular attention is given to discussion of how anti-DNA autoantibody initiates experimental lupus nephritis (LN) in mice.
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38
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Nitschke L. CD22 and Siglec-G regulate inhibition of B-cell signaling by sialic acid ligand binding and control B-cell tolerance. Glycobiology 2014; 24:807-17. [PMID: 25002414 DOI: 10.1093/glycob/cwu066] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CD22 and Siglec-G are two B-cell expressed members of the Siglec (sialic acid-binding immunoglobulin (Ig)-like lectin) family and are potent inhibitors of B-cell signaling. Genetic approaches have provided evidence that this inhibition of B-cell antigen receptor (BCR) signaling by Siglecs is dependent on ligand binding to sialic acids in specific linkages. The cis-ligand-binding activity of CD22 leads to homo-oligomer formation, which are to a large extent found in membrane domains that are distinct from those containing the BCR. In contrast, Siglec-G is recruited via sialic acid binding to the BCR. This interaction of Siglec-G with mIgM leads to an inhibitory function that seems to be specific for B-1 cells. Both CD22 and Siglec-G control B-cell tolerance and loss of these proteins, its ligands or its inhibitory pathways can increase the susceptibility for autoimmune diseases. CD22 is a target protein both in B-cell leukemias and lymphomas, as well as in B-cell mediated autoimmune diseases. Both antibodies and synthetic chemically modified sialic acids are currently tested to target Siglecs on B cells.
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Affiliation(s)
- Lars Nitschke
- Division of Genetics, Department of Biology, University of Erlangen, Erlangen, Germany
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39
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Angata T. Associations of genetic polymorphisms of Siglecs with human diseases. Glycobiology 2014; 24:785-93. [PMID: 24841380 DOI: 10.1093/glycob/cwu043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Genetic polymorphism studies in humans provide unique opportunities to understand human biology and the mechanisms of diseases. Correlations between polymorphisms in the genes encoding human Siglecs and various diseases have been reported. Leading examples, such as the CD33 polymorphism associated with late-onset Alzheimer's disease, are well supported by genetic replication and mechanistic studies, while some others (such as SIGLEC8 polymorphism associated with bronchial asthma and SIGLEC14 polymorphism associated with exacerbation of chronic obstructive pulmonary disease) may benefit reinforcement by independent genetic replication or mechanistic studies. In a few cases, such as MAG polymorphism associated with psychological disorder and CD22 polymorphism associated with autoimmune disease, the phenotype associated with a genetic polymorphism of a Siglec gene and that of an enzyme gene involved in the biosynthesis of Siglec ligand show some overlap, providing indirect support for the observed genotype-phenotype association. Although studies using engineered mutant mice have provided invaluable insights into the biological functions and mechanisms of diseases, it is not always possible to develop appropriate mouse model to replicate human situations because of significant species-to-species differences, which can be a major obstacle in understanding the biology of some of human CD33/Siglec-3-related Siglecs. Further studies in genetic polymorphisms of human Siglecs, combined with appropriate functional studies, may reveal unexpected biological roles of human Siglecs, and identify possible targets for prevention and/or treatment of certain diseases.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang District, Taipei 11529, Taiwan
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40
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Abstract
A high proportion of peripheral human B cells produce polyreactive or autoreactive antibodies, which indicates that they have escaped the elimination of self-reactive B cells in the bone marrow. CD22 and Siglec-G are two inhibitory receptors of the sialic-acid-binding immunoglobulin-like lectin (Siglec) family that inhibit the B-cell antigen receptor (BCR) signal. The ability of these two receptors to bind sialic acids is crucial for regulating inhibition and inducing tolerance to self-antigens. Sialylated glycans are usually absent on microbes (although several pathogenic microorganisms have evolved strategies to mimic self by decorating their surfaces with sialic acids) but abundant in higher vertebrates and might, therefore, provide an important tolerogenic signal. Combined Siglec-G deficiency and CD22 deficiency leads to spontaneous autoimmunity in mice, and mutations in an enzyme that modifies Siglec ligands are directly linked to several autoimmune diseases in humans. New data show that high-affinity ligands for CD22 and Siglec-G can be used to induce antigen-specific B-cell tolerance, which might be one strategy for the treatment of autoimmune diseases in the future.
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41
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Courtney AH, Bennett NR, Zwick DB, Hudon J, Kiessling LL. Synthetic antigens reveal dynamics of BCR endocytosis during inhibitory signaling. ACS Chem Biol 2014; 9:202-10. [PMID: 24131142 DOI: 10.1021/cb400532y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
B cells detect foreign antigens through their B cell antigen receptor (BCR). The BCR, when engaged by antigen, initiates a signaling cascade. Concurrent with signaling is endocytosis of the BCR complex, which acts to downregulate signaling and facilitate uptake of antigen for processing and display on the cell surface. The relationship between signaling and BCR endocytosis is poorly defined. Here, we explore the interplay between BCR endocytosis and antigens that either promote or inhibit B cell activation. Specifically, synthetic antigens were generated that engage the BCR alone or both the BCR and the inhibitory co-receptor CD22. The lectin CD22, a member of the Siglec family, binds sialic acid-containing glycoconjugates found on host tissues, inhibiting BCR signaling to prevent erroneous B cell activation. At low concentrations, antigens that can cocluster the BCR and CD22 promote rapid BCR endocytosis; whereas, slower endocytosis occurs with antigens that bind only the BCR. At higher antigen concentrations, rapid BCR endocytosis occurs upon treatment with either stimulatory or inhibitory antigens. Endocytosis of the BCR, in response to synthetic antigens, results in its entry into early endocytic compartments. Although the CD22-binding antigens fail to activate key regulators of antigen presentation (e.g., Syk), they also promote BCR endocytosis, indicating that inhibitory antigens can be internalized. Together, our observations support a functional role for BCR endocytosis in downregulating BCR signaling. The reduction of cell surface BCR levels in the absence of B cell activation should raise the threshold for BCR subsequent activation. The ability of the activating synthetic antigens to trigger both signaling and entry of the BCR into early endosomes suggests strategies for targeted antigen delivery.
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Affiliation(s)
- Adam H. Courtney
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Nitasha R. Bennett
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel B. Zwick
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Jonathan Hudon
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Laura L. Kiessling
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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42
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Lehmann B, Schwab I, Böhm S, Lux A, Biburger M, Nimmerjahn F. FcγRIIB: a modulator of cell activation and humoral tolerance. Expert Rev Clin Immunol 2014; 8:243-54. [DOI: 10.1586/eci.12.5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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43
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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]
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44
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45
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Lamagna C, Hu Y, DeFranco AL, Lowell CA. B cell-specific loss of Lyn kinase leads to autoimmunity. THE JOURNAL OF IMMUNOLOGY 2013; 192:919-28. [PMID: 24376269 DOI: 10.4049/jimmunol.1301979] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Lyn tyrosine kinase regulates inhibitory signaling in B and myeloid cells: loss of Lyn results in a lupus-like autoimmune disease with hyperactive B cells and myeloproliferation. We have characterized the relative contribution of Lyn-regulated signaling pathways in B cells specifically to the development of autoimmunity by crossing the novel lyn(flox/flox) animals with mice carrying the Cre recombinase under the control of the Cd79a promoter, resulting in deletion of Lyn in B cells. The specific deletion of Lyn in B cells is sufficient for the development of immune complex-mediated glomerulonephritis. The B cell-specific Lyn-deficient mice have no defects in early bone marrow B cell development but have reduced numbers of mature B cells with poor germinal centers, as well as increased numbers of plasma and B1a cells, similar to the lyn(-/-) animals. Within 8 mo of life, B cell-specific Lyn mutant mice develop high titers of IgG anti-Smith Ag ribonucleoprotein and anti-dsDNA autoantibodies, which deposit in their kidneys, resulting in glomerulonephritis. B cell-specific Lyn mutant mice also develop myeloproliferation, similar to the lyn(-/-) animals. The additional deletion of MyD88 in B cells, achieved by crossing lyn(flox/flox)Cd79a-cre mice with myd88(flox/flox) animals, reversed the autoimmune phenotype observed in B cell-specific Lyn-deficient mice by blocking production of class-switched pathogenic IgG autoantibodies. Our results demonstrate that B cell-intrinsic Lyn-dependent signaling pathways regulate B cell homeostasis and activation, which in concert with B cell-specific MyD88 signaling pathways can drive the development of autoimmune disease.
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Affiliation(s)
- Chrystelle Lamagna
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA 94143
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46
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Poe JC, Kountikov EI, Lykken JM, Natarajan A, Marchuk DA, Tedder TF. EndoU is a novel regulator of AICD during peripheral B cell selection. ACTA ACUST UNITED AC 2013; 211:57-69. [PMID: 24344237 PMCID: PMC3892980 DOI: 10.1084/jem.20130648] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Balanced transmembrane signals maintain a competent peripheral B cell pool limited in self-reactive B cells that may produce pathogenic autoantibodies. To identify molecules regulating peripheral B cell survival and tolerance to self-antigens (Ags), a gene modifier screen was performed with B cells from CD22-deficient C57BL/6 (CD22(-/-[B6])) mice that undergo activation-induced cell death (AICD) and fail to up-regulate c-Myc expression after B cell Ag receptor ligation. Likewise, lysozyme auto-Ag-specific B cells in Ig(Tg) hen egg lysozyme (HEL) transgenic mice inhabit the spleen but undergo AICD after auto-Ag encounter. This gene modifier screen identified EndoU, a single-stranded RNA-binding protein of ancient origin, as a major regulator of B cell survival in both models. EndoU gene disruption prevents AICD and normalizes c-Myc expression. These findings reveal that EndoU is a critical regulator of an unexpected and novel RNA-dependent pathway controlling peripheral B cell survival and Ag responsiveness that may contribute to peripheral B cell tolerance.
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Affiliation(s)
- Jonathan C Poe
- Department of Immunology and 2 Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710
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47
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Do inhibitory immune receptors play a role in the etiology of autoimmune disease? Clin Immunol 2013; 150:31-42. [PMID: 24333531 DOI: 10.1016/j.clim.2013.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/07/2013] [Accepted: 11/10/2013] [Indexed: 12/21/2022]
Abstract
Inhibitory receptors are thought to be important in balancing immune responses. The general assumption is that lack of inhibition predisposes for autoimmune diseases. As reviewed here, various experimental and clinical data support this assumption. However, in humans genetic evidence implicates only a limited number of inhibitory receptors. GWAS have established common variation in a few inhibitory receptor genes, such as FCγRIIB, PD-1 and CTLA-4 as risk factors. The question arises whether inhibitory receptor function is a major determinant of autoimmune disease. In this respect, the finding that genetic variation in CSK and PTPN22 is strongly associated with multiple autoimmune diseases is of interest. We propose a model in which the molecules encoded by these genes are downstream of inhibitory receptors. We conclude that common genetic variation of inhibitory receptors, with few exceptions, is not a determining factor for autoimmunity in humans. However, common downstream signaling pathways are.
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48
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Tuscano JM, Martin S, Song K, Wun T. B cell reductive therapy in the treatment of autoimmune diseases: A focus on monoclonal antibody treatment of rheumatoid arthritis. Hematology 2013; 10:521-7. [PMID: 16321818 DOI: 10.1080/10245330500155424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The therapeutic approach to patients with autoimmune disorders is in the midst of a dramatic change. Monoclonal antibody technology has allowed us to dissect and now manipulate the human immune system with greater precision. It is now widely recognized that B lymphocytes play a role in the pathogenesis of many autoimmune diseases, though the extent and contribution is a matter of debate and active investigation. There is emerging data to suggest that both antibody-dependent and independent mechanisms contribute to disease pathogenesis. However, given the heterogeneous nature of autoimmune diseases, and the varied responses to B lymphocyte reduction, the role of B lymphocytes is likely disease-specific. The two clinical trials discussed in this review demonstrate remarkable consistency in the ability of B cell reduction to ameliorate the clinical manifestations of rheumatoid arthritis with minimal toxicity. B lymphocyte targeted approaches to autoimmune disease in general, and RA specifically, will not only provide an effective and potentially less toxic alternative treatment option, but also allow for a better understanding of the pathogenesis of these complex and morbid diseases.
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Affiliation(s)
- Joseph M Tuscano
- University of California, Davis Department of Inter Medicine, Sacramento, CA 95817, USA.
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Abstract
Why exactly some individuals develop autoimmune disorders remains unclear. The broadly accepted paradigm is that genetic susceptibility results in some break in immunological tolerance, may enhance the availability of autoantigens, and may enhance inflammatory responses. Some environmental insults that occur on this background of susceptibility may then contribute to autoimmunity. In this review we discuss some aspects related to inhibitory signaling and rare genetic variants, as well as additional factors that might contribute to autoimmunity including the possible role of clonal somatic mutations, the role of epigenetic events and the contribution of the intestinal microbiome. Genetic susceptibility alleles generally contribute to the loss of immunological tolerance, the increased availability of autoantigens, or an increase in inflammation. Apart from common genetic variants, rare loss-of-function genetic variants may also contribute to the pathogenesis of autoimmunity. Studies of an inhibitory signaling pathway in B cells helped identify a negative regulatory enzyme called sialic acid acetyl esterase. The study of rare genetic variants of this enzyme provides an illustrative example showing the importance of detailed functional analyses of variant alleles and the need to exclude functionally normal common or rare genetic variants from analysis. It has also become clear that pathways that are functionally impacted by either common or rare defective variants can also be more significantly compromised by gene expression changes that may result from epigenetic alterations. Another important and evolving area that has been discussed relates to the role of the intestinal microbiome in influencing helper T cell polarization and the development of autoimmunity.
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Affiliation(s)
- Shiv Pillai
- Massachusetts General Hospital, Center for Cancer Research, Harvard Medical School, Boston, MA 02129, USA.
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Clatworthy MR. B-cell regulation and its application to transplantation. Transpl Int 2013; 27:117-28. [PMID: 23909582 DOI: 10.1111/tri.12160] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 04/08/2013] [Accepted: 07/08/2013] [Indexed: 12/22/2022]
Abstract
There has been increasing interest in the role played by B cells and their associated antibody in the immune response to an allograft, driven by the need to undertake antibody-incompatible transplantation and evidence suggesting that B cells play a role in acute T-cell-mediated rejection and in acute and chronic antibody-mediated rejection. This review focuses on the molecular events, both activating and inhibitory, which control B-cell activation, and considers how this information might inform therapeutic strategies. Potential targets include the BAFF (B-cell-activating factor belonging to the tumour necrosis factor family) and CD40-CD40L pathways and inhibitory molecules, such as CD22 and FcγRIIB. B cells can also play an immunomodulatory role via interleukin (IL)10 production and may contribute to transplant tolerance. The expansion of allograft-specific IL10-producing B cells may be an additional therapeutic goal. Thus, the treatment paradigm required in transplantation has shifted from that of simple B-cell depletion, to that of a more subtle, differential manipulation of different B-cell subsets.
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