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Bende RJ, Slot LM, Kwakkenbos MJ, Wormhoudt TA, Jongejan A, Verstappen GM, van Kampen AC, Guikema JE, Kroese FG, van Noesel CJ. Lymphoma-associated mutations in autoreactive memory B cells of patients with Sjögren's syndrome. J Pathol 2023; 259:264-275. [PMID: 36426826 PMCID: PMC10108009 DOI: 10.1002/path.6039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
We recently demonstrated that normal memory B lymphocytes carry a substantial number of de novo mutations in the genome. Here, we performed exome-wide somatic mutation analyses of bona fide autoreactive rheumatoid factor (RF)-expressing memory B cells retrieved from patients with Sjӧgren's syndrome (SS). The amount and repertoire of the de novo exome mutations of RF B cells were found to be essentially different from those detected in healthy donor memory B cells. In contrast to the mutation spectra of normal B cells, which appeared random and non-selected, the mutations of the RF B cells were greater in number and enriched for mutations in genes also found mutated in B-cell non-Hodgkin lymphomas. During the study, one of the SS patients developed a diffuse large B-cell lymphoma (DLBCL) out of an RF clone that was identified 2 years earlier in an inflamed salivary gland biopsy. The successive oncogenic events in the RF precursor clone and the DLBCL were assessed. In conclusion, our findings of enhanced and selected genomic damage in growth-regulating genes in RF memory B cells of SS patients together with the documented transformation of an RF-precursor clone into DLBCL provide unique novel insight into the earliest stages of B-cell derailment and lymphomagenesis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Richard J Bende
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Lymphoma and Myeloma Center (LYMMCARE), Amsterdam, The Netherlands.,Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Linda M Slot
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Lymphoma and Myeloma Center (LYMMCARE), Amsterdam, The Netherlands.,Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | | | - Thera Am Wormhoudt
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Lymphoma and Myeloma Center (LYMMCARE), Amsterdam, The Netherlands.,Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Aldo Jongejan
- Bioinformatics Laboratory, Epidemiology & Data Science, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Gwenny M Verstappen
- Department of Rheumatology and Clinical Immunology, UMC Groningen, University of Groningen, Groningen, The Netherlands
| | - Antoine Cm van Kampen
- Bioinformatics Laboratory, Epidemiology & Data Science, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Biosystems Data analysis, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeroen Ej Guikema
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Lymphoma and Myeloma Center (LYMMCARE), Amsterdam, The Netherlands.,Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Frans Gm Kroese
- Department of Rheumatology and Clinical Immunology, UMC Groningen, University of Groningen, Groningen, The Netherlands
| | - Carel Jm van Noesel
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Lymphoma and Myeloma Center (LYMMCARE), Amsterdam, The Netherlands.,Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
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Abstract
The central role of calcium (Ca2+) signaling in lymphocyte development and acquisition of functional immunity and tolerance is well established. Ca2+ signals are initiated upon antigen binding to cognate receptors on lymphocytes that trigger store operated Ca2+ entry (SOCE). The underlying mechanism of SOCE in lymphocytes involves TCR and BCR mediated activation of Stromal Interaction Molecule 1 and 2 (STIM1/2) embedded in the ER membrane. Once activated, STIM proteins oligomerize and re-localize to ER domains juxtaposed to the plasma membrane where they activate Orai channels to allow Ca2+ to enter the cell across the plasma membrane. Importantly, STIM/Orai-dependent Ca2+ signals guide antigen induced lymphocyte development and function principally by regulating the activity of transcription factors.The most widely studied of these transcription factors is the Nuclear Factor of Activated T cells (NFAT). NFAT is expressed ubiquitously and the mechanism by which Ca2+ regulates NFAT activation and signaling is well known. By contrast, a mechanistic understanding of how Ca2+ signals also shape the activation and specificity of NF-κB to control the expression of pro-inflammatory genes has lagged. Here we discuss the methodology used to investigate Ca2+ dependent mechanisms of NF-κB activation in lymphocytes. Our approach focuses on three main areas of signal transduction and signaling: (1) antigen receptor engagement and Ca2+ dependent initiation of NF-kB signaling, (2) Ca2+ dependent induction of NF-κB heterodimer activation and nuclear localization, and (3) and how Ca2+ regulates NF-κB dependent expression of target genes and proteins.
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Affiliation(s)
- Corbett T Berry
- Department of Pathobiology, The University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Michael J May
- Department of Biomedical Sciences, The University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
| | - Bruce D Freedman
- Department of Pathobiology, The University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA.
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Griffin MJ, Zhou Y, Kang S, Zhang X, Mikkelsen TS, Rosen ED. Early B-cell factor-1 (EBF1) is a key regulator of metabolic and inflammatory signaling pathways in mature adipocytes. J Biol Chem 2013; 288:35925-39. [PMID: 24174531 DOI: 10.1074/jbc.m113.491936] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
EBF1 plays a crucial role in early adipogenesis; however, despite high expression in mature adipocytes, its function in these cells is currently unknown. To identify direct and indirect EBF1 targets in fat, we undertook a combination of transcriptional profiling of EBF1-deficient adipocytes and genome-wide EBF1 location analysis. Our results indicate that many components of metabolic and inflammatory pathways are positively and directly regulated by EBF1, including PI3K/AKT, MAPK, and STAT1 signaling. Accordingly, we observed significant reduction of multiple signaling events in EBF1 knockdown cells as well as a reduction in insulin-stimulated glucose uptake and lipogenesis. Inflammatory signaling, gene expression, and secretion of inflammatory cytokines were also significantly affected by loss of EBF1 in adipocytes, although ChIP-sequencing results suggest that these actions are indirect. We also found that EBF1 occupies some 35,000 sites in adipocytes, most of which occur in enhancers. Significantly, comparison with three other published EBF1 ChIP-sequencing data sets in B-cells reveals both gene- and cell type-specific patterns of EBF1 binding. These results advance our understanding of the transcriptional mechanisms regulating signaling pathways in mature fat cells and indicate that EBF1 functions as a key integrator of signal transduction, inflammation, and metabolism.
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Affiliation(s)
- Michael J Griffin
- From the Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215
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