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Maffei R, Fiorcari S, Atene CG, Martinelli S, Mesini N, Pilato F, Lagreca I, Barozzi P, Riva G, Nasillo V, Paolini A, Forghieri F, Potenza L, Trenti T, Tagliafico E, Luppi M, Marasca R. The dynamic functions of IRF4 in B cell malignancies. Clin Exp Med 2022:10.1007/s10238-022-00968-0. [PMID: 36495369 PMCID: PMC10390622 DOI: 10.1007/s10238-022-00968-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022]
Abstract
AbstractThe trajectory of B cell development goes through subsequent steps governed by complex genetic programs, strictly regulated by multiple transcription factors. Interferon regulatory factor 4 (IRF4) regulates key points from pre-B cell development and receptor editing to germinal center formation, class-switch recombination and plasma cell differentiation. The pleiotropic ability of IRF4 is mediated by its “kinetic control”, allowing different IRF4 expression levels to activate distinct genetic programs due to modulation of IRF4 DNA-binding affinity. IRF4 is implicated in B cell malignancies, acting both as tumor suppressor and as tumor oncogene in different types of precursors and mature B cell neoplasia. Here, we summarize the complexity of IRF4 functions related to different DNA-binding affinity, multiple IRF4-specific target DNA motif, and interactions with transcriptional partners. Moreover, we describe the unique role of IRF4 in acute leukemias and B cell mature neoplasia, focusing on pathogenetic implications and possible therapeutic strategies in multiple myeloma and chronic lymphocytic leukemia.
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2
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Deng X, Zhang M, Zhou J, Xiao M. Next-generation sequencing for MRD monitoring in B-lineage malignancies: from bench to bedside. Exp Hematol Oncol 2022; 11:50. [PMID: 36057673 PMCID: PMC9440501 DOI: 10.1186/s40164-022-00300-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 08/21/2022] [Indexed: 12/02/2022] Open
Abstract
Minimal residual disease (MRD) is considered the strongest relevant predictor of prognosis and an effective decision-making factor during the treatment of hematological malignancies. Remarkable breakthroughs brought about by new strategies, such as epigenetic therapy and chimeric antigen receptor-T (CAR-T) therapy, have led to considerably deeper responses in patients than ever, which presents difficulties with the widely applied gold-standard techniques of MRD monitoring. Urgent demands for novel approaches that are ultrasensitive and provide sufficient information have put a spotlight on high-throughput technologies. Recently, advances in methodology, represented by next-generation sequencing (NGS)-based clonality assays, have proven robust and suggestive in numerous high-quality studies and have been recommended by some international expert groups as disease-monitoring modalities. This review demonstrates the applicability of NGS-based clonality assessment for MRD monitoring of B-cell malignancies by summarizing the oncogenesis of neoplasms and the corresponding status of immunoglobulin (IG) rearrangements. Furthermore, we focused on the performance of NGS-based assays compared with conventional approaches and the interpretation of results, revealing directions for improvement and prospects in clinical practice.
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Affiliation(s)
- Xinyue Deng
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.,Immunotherapy Research Center for Hematologic Diseases of Hubei Province, Wuhan, Hubei, 430030, China
| | - Meilan Zhang
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.,Immunotherapy Research Center for Hematologic Diseases of Hubei Province, Wuhan, Hubei, 430030, China
| | - Jianfeng Zhou
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.,Immunotherapy Research Center for Hematologic Diseases of Hubei Province, Wuhan, Hubei, 430030, China
| | - Min Xiao
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China. .,Immunotherapy Research Center for Hematologic Diseases of Hubei Province, Wuhan, Hubei, 430030, China.
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3
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Presence of Natural Killer B Cells in Simian Immunodeficiency Virus-Infected Colon That Have Properties and Functions Similar to Those of Natural Killer Cells and B Cells but Are a Distinct Cell Population. J Virol 2022; 96:e0023522. [PMID: 35311549 PMCID: PMC9006943 DOI: 10.1128/jvi.00235-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
There is low-level but significant mucosal inflammation in the gastrointestinal tract secondary to human immunodeficiency virus (HIV) infection that has long-term consequences for the infected host. This inflammation most likely originates from the immune response that appears as a consequence of HIV. Here, we show in an animal model of HIV that the chronically SIV-infected gut contains cytotoxic natural killer B cells that produce inflammatory cytokines and proliferate during infection.
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4
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Sinkora M, Stepanova K, Butler JE, Sinkora M, Sinkora S, Sinkorova J. Comparative Aspects of Immunoglobulin Gene Rearrangement Arrays in Different Species. Front Immunol 2022; 13:823145. [PMID: 35222402 PMCID: PMC8873125 DOI: 10.3389/fimmu.2022.823145] [Citation(s) in RCA: 2] [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: 11/26/2021] [Accepted: 01/24/2022] [Indexed: 11/25/2022] Open
Abstract
Studies in humans and mice indicate the critical role of the surrogate light chain in the selection of the productive immunoglobulin repertoire during B cell development. However, subsequent studies using mutant mice have also demonstrated that alternative pathways are allowed. Our recent investigation has shown that some species, such as pig, physiologically use preferential rearrangement of authentic light chains, and become independent of surrogate light chains. Here we summarize the findings from swine and compare them with results in other species. In both groups, allelic and isotypic exclusions remain intact, so the different processes do not alter the paradigm of B-cell monospecificity. Both groups also retained some other essential processes, such as segregated and sequential rearrangement of heavy and light chain loci, preferential rearrangement of light chain kappa before lambda, and functional κ-deleting element recombination. On the other hand, the respective order of heavy and light chains rearrangement may vary, and rearrangement of the light chain kappa and lambda on different chromosomes may occur independently. Studies have also confirmed that the surrogate light chain is not required for the selection of the productive repertoire of heavy chains and can be substituted by authentic light chains. These findings are important for understanding evolutional approaches, redundancy and efficiency of B-cell generation, dependencies on other regulatory factors, and strategies for constructing therapeutic antibodies in unrelated species. The results may also be important for explaining interspecies differences in the proportional use of light chains and for the understanding of divergences in rearrangement processes. Therefore, the division into two groups may not be definitive and there may be more groups of intermediate species.
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Affiliation(s)
- Marek Sinkora
- Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
- *Correspondence: Marek Sinkora,
| | - Katerina Stepanova
- Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
| | - John E. Butler
- Department of Microbiology, University of Iowa, Iowa City, IA, United States
| | - Marek Sinkora
- Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
| | - Simon Sinkora
- Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
| | - Jana Sinkorova
- Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
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5
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Müschen M. Metabolic gatekeepers to safeguard against autoimmunity and oncogenic B cell transformation. Nat Rev Immunol 2019; 19:337-348. [DOI: 10.1038/s41577-019-0154-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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6
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Su L, Wang C, Zheng C, Wei H, Song X. A meta-analysis of public microarray data identifies biological regulatory networks in Parkinson's disease. BMC Med Genomics 2018; 11:40. [PMID: 29653596 PMCID: PMC5899355 DOI: 10.1186/s12920-018-0357-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Parkinson's disease (PD) is a long-term degenerative disease that is caused by environmental and genetic factors. The networks of genes and their regulators that control the progression and development of PD require further elucidation. METHODS We examine common differentially expressed genes (DEGs) from several PD blood and substantia nigra (SN) microarray datasets by meta-analysis. Further we screen the PD-specific genes from common DEGs using GCBI. Next, we used a series of bioinformatics software to analyze the miRNAs, lncRNAs and SNPs associated with the common PD-specific genes, and then identify the mTF-miRNA-gene-gTF network. RESULT Our results identified 36 common DEGs in PD blood studies and 17 common DEGs in PD SN studies, and five of the genes were previously known to be associated with PD. Further study of the regulatory miRNAs associated with the common PD-specific genes revealed 14 PD-specific miRNAs in our study. Analysis of the mTF-miRNA-gene-gTF network about PD-specific genes revealed two feed-forward loops: one involving the SPRK2 gene, hsa-miR-19a-3p and SPI1, and the second involving the SPRK2 gene, hsa-miR-17-3p and SPI. The long non-coding RNA (lncRNA)-mediated regulatory network identified lncRNAs associated with PD-specific genes and PD-specific miRNAs. Moreover, single nucleotide polymorphism (SNP) analysis of the PD-specific genes identified two significant SNPs, and SNP analysis of the neurodegenerative disease-specific genes identified seven significant SNPs. Most of these SNPs are present in the 3'-untranslated region of genes and are controlled by several miRNAs. CONCLUSION Our study identified a total of 53 common DEGs in PD patients compared with healthy controls in blood and brain datasets and five of these genes were previously linked with PD. Regulatory network analysis identified PD-specific miRNAs, associated long non-coding RNA and feed-forward loops, which contribute to our understanding of the mechanisms underlying PD. The SNPs identified in our study can determine whether a genetic variant is associated with PD. Overall, these findings will help guide our study of the complex molecular mechanism of PD.
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Affiliation(s)
- Lining Su
- Department of Biology of Basic Medical Science College, Hebei North University, Zhangjiakou, 075000, Hebei, China
| | - Chunjie Wang
- Department of Basic Medicine, Zhangjiakou University, Zhangjiakou, 75000, Hebei, China
| | - Chenqing Zheng
- Shenzhen RealOmics (Biotech) Co., Ltd, Shenzhen, 518081, Guangdong, China
| | - Huiping Wei
- Department of Biology of Basic Medical Science College, Hebei North University, Zhangjiakou, 075000, Hebei, China.
| | - Xiaoqing Song
- Department of Biology of Basic Medical Science College, Hebei North University, Zhangjiakou, 075000, Hebei, China
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Lang J, Ota T, Kelly M, Strauch P, Freed BM, Torres RM, Nemazee D, Pelanda R. Receptor editing and genetic variability in human autoreactive B cells. J Exp Med 2015; 213:93-108. [PMID: 26694971 PMCID: PMC4710202 DOI: 10.1084/jem.20151039] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 11/23/2015] [Indexed: 12/11/2022] Open
Abstract
Lang et al. show in a humanized mouse model that human B cells undergo central tolerance via a combination of receptor editing and clonal deletion. The mechanisms by which B cells undergo tolerance, such as receptor editing, clonal deletion, and anergy, have been established in mice. However, corroborating these mechanisms in humans remains challenging. To study how autoreactive human B cells undergo tolerance, we developed a novel humanized mouse model. Mice expressing an anti–human Igκ membrane protein to serve as a ubiquitous neo self-antigen (Ag) were transplanted with a human immune system. By following the fate of self-reactive human κ+ B cells relative to nonautoreactive λ+ cells, we show that tolerance of human B cells occurs at the first site of self-Ag encounter, the bone marrow, via a combination of receptor editing and clonal deletion. Moreover, the amount of available self-Ag and the genetics of the cord blood donor dictate the levels of central tolerance and autoreactive B cells in the periphery. Thus, this model can be useful for studying specific mechanisms of human B cell tolerance and to reveal differences in the extent of this process among human populations.
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Affiliation(s)
- Julie Lang
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Takayuki Ota
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Margot Kelly
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Pamela Strauch
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Brian M Freed
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Division of Allergy and Clinical Immunology, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Raul M Torres
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - David Nemazee
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Roberta Pelanda
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
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NF-κB and AKT signaling prevent DNA damage in transformed pre-B cells by suppressing RAG1/2 expression and activity. Blood 2015; 126:1324-35. [PMID: 26153519 DOI: 10.1182/blood-2015-01-621623] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 07/01/2015] [Indexed: 01/16/2023] Open
Abstract
In developing lymphocytes, expression and activity of the recombination activation gene protein 1 (RAG1) and RAG2 endonuclease complex is tightly regulated to ensure ordered recombination of the immunoglobulin genes and to avoid genomic instability. Aberrant RAG activity has been implicated in the generation of secondary genetic events in human B-cell acute lymphoblastic leukemias (B-ALLs), illustrating the oncogenic potential of the RAG complex. Several layers of regulation prevent collateral genomic DNA damage by restricting RAG activity to the G1 phase of the cell cycle. In this study, we show a novel pathway that suppresses RAG expression in cycling-transformed mouse pre-B cells and human pre-B B-ALL cells that involves the negative regulation of FOXO1 by nuclear factor κB (NF-κB). Inhibition of NF-κB in cycling pre-B cells resulted in upregulation of RAG expression and recombination activity, which provoked RAG-dependent DNA damage. In agreement, we observe a negative correlation between NF-κB activity and the expression of RAG1, RAG2, and TdT in B-ALL patients. Our data suggest that targeting NF-κB in B-ALL increases the risk of RAG-dependent genomic instability.
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Abstract
The oncomir microRNA-125b (miR-125b) is upregulated in a variety of human neoplastic blood disorders and constitutive upregulation of miR-125b in mice can promote myeloid and B-cell leukemia. We found that miR-125b promotes myeloid and B-cell neoplasm by inducing tumorigenesis in hematopoietic progenitor cells. Our study demonstrates that miR-125b induces myeloid leukemia by enhancing myeloid progenitor output from stem cells as well as inducing immortality, self-renewal, and tumorigenesis in myeloid progenitors. Through functional and genetic analyses, we demonstrated that miR-125b induces myeloid and B-cell leukemia by inhibiting interferon regulatory factor 4 (IRF4) but through distinct mechanisms; it induces myeloid leukemia through repressing IRF4 at the messenger RNA (mRNA) level without altering the genomic DNA and induces B-cell leukemia via genetic deletion of the gene encoding IRF4.
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10
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Gang EJ, Hsieh YT, Pham J, Zhao Y, Nguyen C, Huantes S, Park E, Naing K, Klemm L, Swaminathan S, Conway EM, Pelus LM, Crispino J, Mullighan C, McMillan M, Müschen M, Kahn M, Kim YM. Small-molecule inhibition of CBP/catenin interactions eliminates drug-resistant clones in acute lymphoblastic leukemia. Oncogene 2014; 33:2169-78. [PMID: 23728349 PMCID: PMC3994178 DOI: 10.1038/onc.2013.169] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 03/04/2013] [Accepted: 03/25/2013] [Indexed: 02/07/2023]
Abstract
Drug resistance in acute lymphoblastic leukemia (ALL) remains a major problem warranting new treatment strategies. Wnt/catenin signaling is critical for the self-renewal of normal hematopoietic progenitor cells. Deregulated Wnt signaling is evident in chronic and acute myeloid leukemia; however, little is known about ALL. Differential interaction of catenin with either the Kat3 coactivator CREBBP (CREB-binding protein (CBP)) or the highly homologous EP300 (p300) is critical to determine divergent cellular responses and provides a rationale for the regulation of both proliferation and differentiation by the Wnt signaling pathway. Usage of the coactivator CBP by catenin leads to transcriptional activation of cassettes of genes that are involved in maintenance of progenitor cell self-renewal. However, the use of the coactivator p300 leads to activation of genes involved in the initiation of differentiation. ICG-001 is a novel small-molecule modulator of Wnt/catenin signaling, which specifically binds to the N-terminus of CBP and not p300, within amino acids 1-110, thereby disrupting the interaction between CBP and catenin. Here, we report that selective disruption of the CBP/β- and γ-catenin interactions using ICG-001 leads to differentiation of pre-B ALL cells and loss of self-renewal capacity. Survivin, an inhibitor-of-apoptosis protein, was also downregulated in primary ALL after treatment with ICG-001. Using chromatin immunoprecipitation assay, we demonstrate occupancy of the survivin promoter by CBP that is decreased by ICG-001 in primary ALL. CBP mutations have been recently identified in a significant percentage of ALL patients, however, almost all of the identified mutations reported occur C-terminal to the binding site for ICG-001. Importantly, ICG-001, regardless of CBP mutational status and chromosomal aberration, leads to eradication of drug-resistant primary leukemia in combination with conventional therapy in vitro and significantly prolongs the survival of NOD/SCID mice engrafted with primary ALL. Therefore, specifically inhibiting CBP/catenin transcription represents a novel approach to overcome relapse in ALL.
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Affiliation(s)
- Eun Ji Gang
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Yao-Te Hsieh
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Jennifer Pham
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Yi Zhao
- Norris Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Department of Molecular Pharmacology and Toxicology, Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA
| | - Cu Nguyen
- Norris Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Department of Molecular Pharmacology and Toxicology, Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA
| | - Sandra Huantes
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Eugene Park
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Khatija Naing
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Lars Klemm
- Comprehensive Cancer Center, Department of Laboratory Medicine, University of California, San Francisco, California
| | - Srividya Swaminathan
- Comprehensive Cancer Center, Department of Laboratory Medicine, University of California, San Francisco, California
| | - Edward M. Conway
- Centre for Blood Research (CBR), Faculty of Medicine, Division of Hematology, University of British Columbia, Canada
| | - Louis M. Pelus
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis
| | - John Crispino
- Division of Hematology/Oncology, Northwestern University, Chicago
| | - Charles Mullighan
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Michael McMillan
- Norris Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Department of Molecular Pharmacology and Toxicology, Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA
| | - Markus Müschen
- Comprehensive Cancer Center, Department of Laboratory Medicine, University of California, San Francisco, California
| | - Michael Kahn
- Norris Comprehensive Cancer Center, Department of Biochemistry and Molecular Biology, Department of Molecular Pharmacology and Toxicology, Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA
| | - Yong-Mi Kim
- Childrens Hospital Los Angeles, Division of Hematology and Oncology, Department of Pediatrics, University of Southern California, Keck School of Medicine, Los Angeles, CA
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Banerjee S, Lu J, Cai Q, Saha A, Jha HC, Dzeng RK, Robertson ES. The EBV Latent Antigen 3C Inhibits Apoptosis through Targeted Regulation of Interferon Regulatory Factors 4 and 8. PLoS Pathog 2013; 9:e1003314. [PMID: 23658517 PMCID: PMC3642079 DOI: 10.1371/journal.ppat.1003314] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 03/04/2013] [Indexed: 12/15/2022] Open
Abstract
Epstein-Barr virus (EBV) is linked to a broad spectrum of B-cell malignancies. EBV nuclear antigen 3C (EBNA3C) is an encoded latent antigen required for growth transformation of primary human B-lymphocytes. Interferon regulatory factor 4 (IRF4) and 8 (IRF8) are transcription factors of the IRF family that regulate diverse functions in B cell development. IRF4 is an oncoprotein with anti-apoptotic properties and IRF8 functions as a regulator of apoptosis and tumor suppressor in many hematopoietic malignancies. We now demonstrate that EBNA3C can contribute to B-cell transformation by modulating the molecular interplay between cellular IRF4 and IRF8. We show that EBNA3C physically interacts with IRF4 and IRF8 with its N-terminal domain in vitro and forms a molecular complex in cells. We identified the Spi-1/B motif of IRF4 as critical for EBNA3C interaction. We also demonstrated that EBNA3C can stabilize IRF4, which leads to downregulation of IRF8 by enhancing its proteasome-mediated degradation. Further, si-RNA mediated knock-down of endogenous IRF4 results in a substantial reduction in proliferation of EBV-transformed lymphoblastoid cell lines (LCLs), as well as augmentation of DNA damage-induced apoptosis. IRF4 knockdown also showed reduced expression of its targeted downstream signalling proteins which include CDK6, Cyclin B1 and c-Myc all critical for cell proliferation. These studies provide novel insights into the contribution of EBNA3C to EBV-mediated B-cell transformation through regulation of IRF4 and IRF8 and add another molecular link to the mechanisms by which EBV dysregulates cellular activities, increasing the potential for therapeutic intervention against EBV-associated cancers. Interferon regulatory factor (IRF) family members have different roles in context of pathogen response, signal transduction, cell proliferation and hematopoietic development. IRF4 and IRF8 are members of the IRF family and are critical mediators of B-cell development. Enhanced expression of IRF4 is often associated with multiple myeloma and adult T-cell lymphomas. Furthermore, IRF8 can function as a tumor suppressor in myeloid cancers. Epstein-Barr virus (EBV), one of the first characterized human tumor viruses is associated with several lymphoid malignancies. One of the essential antigens, EBV encoded nuclear antigen 3C (EBNA3C), plays a critical role in EBV-induced B-cell transformation. In our study, we now demonstrate that EBNA3C forms a molecular complex with IRF4 and IRF8 specifically through its N-terminal domain. We show that IRF4 is stabilized by EBNA3C, which resulted in downregulation of IRF8 through proteasome-mediated degradation and subsequent inhibition of its tumor suppressive activity. Moreover, si-RNA-mediated inhibition of IRF4 showed a substantial reduction in EBV transformed B-cell proliferation, and also enhanced their sensitivity to DNA-damage induced apoptosis. Therefore, our findings demonstrated that targeted disruption of EBNA3C-mediated differential regulation of IRF4 and IRF8 may have potential therapeutic value for treating EBV induced B-cell malignancies.
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Affiliation(s)
- Shuvomoy Banerjee
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jie Lu
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Qiliang Cai
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Abhik Saha
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hem Chandra Jha
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Richard Kuo Dzeng
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Erle S. Robertson
- Department of Microbiology and the Tumor Virology Program, Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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SPIB, a novel immunohistochemical marker for human blastic plasmacytoid dendritic cell neoplasms: characterization of its expression in major hematolymphoid neoplasms. Blood 2012; 121:643-7. [PMID: 23165482 DOI: 10.1182/blood-2012-08-447599] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SPIB is an Ets transcription factor that is expressed exclusively in mature B cells, T-cell progenitors, and plasmacytoid dendritic cells. In the present study, we developed a novel mAb against the SPIB protein and characterized its expression in major hematolymphoid neoplasms, including a series of 45 cases of blastic plasmacytoid dendritic cell (BPDC) neoplasms and their potential cutaneous mimics. We found that SPIB is expressed heterogeneously among B- and T-cell lymphoma types. Interestingly, SPIB is expressed in a large proportion of nongerminal center type DLBCLs. In cutaneous neoplasms, SPIB is overexpressed in all BPDC neoplasms, but none of its cutaneous mimics. SPIB remains overexpressed in all cases that lack 1 or 2 of the markers used for BPDC neoplasms (ie, CD4, CD56, TCL1, and CD123). We conclude that SPIB expression can be used as a tool for diagnosing BPDC neoplasms, but it needs to be tested in conjunction with the growing arsenal of markers for human plasmacytoid dendritic cells.
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B cell receptor light chain repertoires show signs of selection with differences between groups of healthy individuals and SLE patients. Mol Immunol 2012; 51:273-82. [PMID: 22516082 DOI: 10.1016/j.molimm.2012.03.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 03/01/2012] [Accepted: 03/22/2012] [Indexed: 02/06/2023]
Abstract
We have developed a microarray to study the expression of L-chain V genes (V(L) genes) in healthy and SLE patient peripheral κ- and λ-sorted B cells. In all repertoires tested, one V(L) gene accounts for over 10% of all gene V(L) expression, consistent with positive selection acting on L-chains. While a few V(L) genes were highly expressed in all individuals, most V(L) genes were expressed at different levels. Some V(L) genes (5 out of a total of 78) were not detected. We attribute their absence from the repertoire to negative selection. Positive selection and negative selection were also found in SLE repertoires, but expression of V(L) genes was different; the differences point to less regulation of V(L) gene repertoires in SLE. Our data shows that V(L) gene expression is variable and supports a model where the L-chain repertoire is generated by both positive and negative selection on L-chains.
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De Silva NS, Simonetti G, Heise N, Klein U. The diverse roles of IRF4 in late germinal center B-cell differentiation. Immunol Rev 2012; 247:73-92. [DOI: 10.1111/j.1600-065x.2012.01113.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Hassaballa AE, Palmer VL, Anderson DK, Kassmeier MD, Nganga VK, Parks KW, Volkmer DL, Perry GA, Swanson PC. Accumulation of B1-like B cells in transgenic mice over-expressing catalytically inactive RAG1 in the periphery. Immunology 2012; 134:469-86. [PMID: 22044391 DOI: 10.1111/j.1365-2567.2011.03509.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
During their development, B lymphocytes undergo V(D)J recombination events and selection processes that, if successfully completed, produce mature B cells expressing a non-self-reactive B-cell receptor (BCR). Primary V(D)J rearrangements yield self-reactive B cells at high frequency, triggering attempts to remove, silence, or reprogramme them through deletion, anergy induction, or secondary V(D)J recombination (receptor editing), respectively. In principle, expressing a catalytically inactive V(D)J recombinase during a developmental stage in which V(D)J rearrangement is initiated may impair this process. To test this idea, we generated transgenic mice expressing a RAG1 active site mutant (dnRAG1 mice); RAG1 transcript was elevated in splenic, but not bone marrow, B cells in dnRAG1 mice relative to wild-type mice. The dnRAG1 mice accumulate splenic B cells with a B1-like phenotype that exhibit defects in B-cell activation, and are clonally diverse, yet repertoire restricted with a bias toward Jκ1 gene segment usage. The dnRAG1 mice show evidence of impaired B-cell development at the immature-to-mature transition, immunoglobulin deficiency, and poorer immune responses to thymus-independent antigens. Interestingly, dnRAG1 mice expressing the anti-dsDNA 3H9H56R heavy chain fail to accumulate splenic B1-like cells, yet retain peritoneal B1 cells. Instead, these mice show an expanded marginal zone compartment, but no difference is detected in the frequency of heavy chain gene replacement. Taken together, these data suggest a model in which dnRAG1 expression impairs secondary V(D)J recombination. As a result, selection and/or differentiation processes are altered in a way that promotes expansion of B1-like B cells in the spleen.
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Affiliation(s)
- Ashraf E Hassaballa
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178, USA
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16
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Jo SH, Ren R. IRF-4 suppresses BCR/ABL transformation of myeloid cells in a DNA binding-independent manner. J Biol Chem 2011; 287:1770-8. [PMID: 22110133 DOI: 10.1074/jbc.m111.289728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Interferon regulatory factor 4 (IRF-4) is essential for B and T cell development and immune response regulation, and has both nuclear and cytoplasmic functions. IRF-4 was originally identified as a proto-oncogene resulting from a t(6;14) chromosomal translocation in multiple myeloma and its expression was shown to be essential for multiple myeloma cell survival. However, we have previously shown that IRF-4 functions as a tumor suppressor in the myeloid lineage and in early stages of B cell development. In this study, we found that IRF-4 suppresses BCR/ABL transformation of myeloid cells. To gain insight into the molecular pathways that mediate IRF-4 tumor suppressor function, we performed a structure-function analysis of IRF-4 as a suppressor of BCR/ABL transformation. We found that the DNA binding domain deletion mutant of IRF-4, which is localized only in the cytoplasm, is still able to inhibit BCR/ABL transformation of myeloid cells. IRF-4 also functions as a tumor suppressor in bone marrow cells deficient in MyD88, an IRF-4-interacting protein found in the cytoplasm. However, IRF-4 tumor suppressor activity is lost in IRF association domain (IAD) deletion mutants. These results demonstrate that IRF-4 suppresses BCR/ABL transformation by a novel cytoplasmic function involving its IAD domain.
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Affiliation(s)
- Seung-Hee Jo
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02454, USA
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17
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Edholm ES, Wilson M, Bengten E. Immunoglobulin light (IgL) chains in ectothermic vertebrates. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:906-915. [PMID: 21256861 DOI: 10.1016/j.dci.2011.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 01/16/2011] [Accepted: 01/16/2011] [Indexed: 05/30/2023]
Abstract
Four major ancesteral IgL isotypes have been identified κ, λ, σ and σ-cart. However, depending on the vertebrate class the genomic representation of these isotypes differs in regards to what is encoded in the germline and how these genes are organized. Also, the relative contribution of each isotype in immune responses varies. This review focuses on the IgL chains of ectothermic vertebrates, specifically the number of different isotypes, their phylogenetic relationship, genomic organizations and expression.
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Affiliation(s)
- Eva-Stina Edholm
- Department of Microbiology, University of Mississippi Medical Center, Jackson, MS 39216, United States
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18
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Zakharova ES, Kazilo NA, Stefanov DN, Sinitsyna MN, Kovrigina AM. Genetic bases of the repertoire of immunoglobulins in application to diagnostics of clonality of B-cell lymphoid populations. RUSS J GENET+ 2011. [DOI: 10.1134/s1022795411050188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Arbuckle JL, Rahman NS, Zhao S, Rodgers W, Rodgers KK. Elucidating the domain architecture and functions of non-core RAG1: the capacity of a non-core zinc-binding domain to function in nuclear import and nucleic acid binding. BMC BIOCHEMISTRY 2011; 12:23. [PMID: 21599978 PMCID: PMC3124419 DOI: 10.1186/1471-2091-12-23] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 05/20/2011] [Indexed: 12/19/2022]
Abstract
Background The repertoire of the antigen-binding receptors originates from the rearrangement of immunoglobulin and T-cell receptor genetic loci in a process known as V(D)J recombination. The initial site-specific DNA cleavage steps of this process are catalyzed by the lymphoid specific proteins RAG1 and RAG2. The majority of studies on RAG1 and RAG2 have focused on the minimal, core regions required for catalytic activity. Though not absolutely required, non-core regions of RAG1 and RAG2 have been shown to influence the efficiency and fidelity of the recombination reaction. Results Using a partial proteolysis approach in combination with bioinformatics analyses, we identified the domain boundaries of a structural domain that is present in the 380-residue N-terminal non-core region of RAG1. We term this domain the Central Non-core Domain (CND; residues 87-217). Conclusions We show how the CND alone, and in combination with other regions of non-core RAG1, functions in nuclear localization, zinc coordination, and interactions with nucleic acid. Together, these results demonstrate the multiple roles that the non-core region can play in the function of the full length protein.
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Affiliation(s)
- Janeen L Arbuckle
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA
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20
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Cooperation between deficiencies of IRF-4 and IRF-8 promotes both myeloid and lymphoid tumorigenesis. Blood 2010; 116:2759-67. [PMID: 20585039 DOI: 10.1182/blood-2009-07-234559] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Interferon regulatory factor 4 (IRF-4) plays important functions in B- and T-cell development and immune response regulation and was originally identified as the product of a proto-oncogene involved in chromosomal translocations in multiple myeloma. Although IRF-4 is expressed in myeloid cells, its function in that lineage is not known. The closely related family member IRF-8 is a critical regulator of myelopoiesis, which when deleted in mice results in a syndrome highly similar to human chronic myelogenous leukemia. In early lymphoid development, we have shown previously that IRF-4 and IRF-8 can function redundantly. We therefore investigated the effects of a combined loss of IRF-4 and IRF-8 on hematologic tumorigenesis. We found that mice deficient in both IRF-4 and IRF-8 develop from a very early age a more aggressive chronic myelogenous leukemia-like disease than mice deficient in IRF-8 alone, correlating with a greater expansion of granulocyte-monocyte progenitors. Although these results demonstrate, for the first time, that IRF-4 can function as tumor suppressor in myeloid cells, interestingly, all mice deficient in both IRF-4 and IRF-8 eventually develop and die of a B-lymphoblastic leukemia/lymphoma. Combined losses of IRF-4 and IRF-8 therefore can cooperate in the development of both myeloid and lymphoid tumors.
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21
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Duy C, Yu JJ, Nahar R, Swaminathan S, Kweon SM, Polo JM, Valls E, Klemm L, Shojaee S, Cerchietti L, Schuh W, Jäck HM, Hurtz C, Ramezani-Rad P, Herzog S, Jumaa H, Koeffler HP, de Alborán IM, Melnick AM, Ye BH, Müschen M. BCL6 is critical for the development of a diverse primary B cell repertoire. ACTA ACUST UNITED AC 2010; 207:1209-21. [PMID: 20498019 PMCID: PMC2882829 DOI: 10.1084/jem.20091299] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BCL6 protects germinal center (GC) B cells against DNA damage-induced apoptosis during somatic hypermutation and class-switch recombination. Although expression of BCL6 was not found in early IL-7-dependent B cell precursors, we report that IL-7Ralpha-Stat5 signaling negatively regulates BCL6. Upon productive VH-DJH gene rearrangement and expression of a mu heavy chain, however, activation of pre-B cell receptor signaling strongly induces BCL6 expression, whereas IL-7Ralpha-Stat5 signaling is attenuated. At the transition from IL-7-dependent to -independent stages of B cell development, BCL6 is activated, reaches expression levels resembling those in GC B cells, and protects pre-B cells from DNA damage-induced apoptosis during immunoglobulin (Ig) light chain gene recombination. In the absence of BCL6, DNA breaks during Ig light chain gene rearrangement lead to excessive up-regulation of Arf and p53. As a consequence, the pool of new bone marrow immature B cells is markedly reduced in size and clonal diversity. We conclude that negative regulation of Arf by BCL6 is required for pre-B cell self-renewal and the formation of a diverse polyclonal B cell repertoire.
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Affiliation(s)
- Cihangir Duy
- Childrens Hospital Los Angeles and Leukemia and Lymphoma Program, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90027, USA
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22
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Nahar R, Müschen M. Pre-B cell receptor signaling in acute lymphoblastic leukemia. Cell Cycle 2009; 8:3874-7. [PMID: 19901533 DOI: 10.4161/cc.8.23.10035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
B cell lineage ALL represents by far the most frequent malignancy in children and is also common in adults. Despite significant advances over the past four decades, cytotoxic treatment strategies have recently reached a plateau with cure rates at 80 percent for children and 55 percent for adults. Relapse after cytotoxic drug treatment, initial drug-resistance and dose-limiting toxicity are among the most frequent complications of current therapy approaches. For this reason, pathway-specific treatment strategies in addition to cytotoxic drug treatment seem promising to further improve therapy options for ALL patients. In a recent study on 111 cases of pre-B cell-derived human ALL, we found that ALL cells carrying a BCR-ABL1-gene rearrangement lack expression of a functional pre-B cell receptor in virtually all cases. In a proof-of-principle experiment, we studied pre-B cell receptor function during progressive leukemic transformation of pre-B cells in BCR-ABL1-transgenic mice: Interestingly, signaling from the pre-B cell receptor and the oncogenic BCR-ABL1 kinase are mutually exclusive and only "crippled" pre-B cells that fail to express a functional pre-B cell receptor are permissive to transformation by BCR-ABL1.
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Affiliation(s)
- Rahul Nahar
- Leukemia and Lymphoma Program, USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA
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23
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Panigrahi AK, Goodman NG, Eisenberg RA, Rickels MR, Naji A, Luning Prak ET. RS rearrangement frequency as a marker of receptor editing in lupus and type 1 diabetes. ACTA ACUST UNITED AC 2008; 205:2985-94. [PMID: 19075293 PMCID: PMC2605238 DOI: 10.1084/jem.20082053] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Continued antibody gene rearrangement, termed receptor editing, is an important mechanism of central B cell tolerance that may be defective in some autoimmune individuals. We describe a quantitative assay for recombining sequence (RS) rearrangement that we use to estimate levels of antibody light chain receptor editing in various B cell populations. RS rearrangement is a recombination of a noncoding gene segment in the κ antibody light chain locus. RS rearrangement levels are highest in the most highly edited B cells, and are inappropriately low in autoimmune mouse models of systemic lupus erythematosus (SLE) and type 1 diabetes (T1D), including those without overt disease. Low RS rearrangement levels are also observed in human subjects with SLE or T1D.
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Affiliation(s)
- Anil K Panigrahi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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24
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Acquaviva J, Chen X, Ren R. IRF-4 functions as a tumor suppressor in early B-cell development. Blood 2008; 112:3798-806. [PMID: 18713947 PMCID: PMC2572804 DOI: 10.1182/blood-2007-10-117838] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 07/19/2008] [Indexed: 12/25/2022] Open
Abstract
Interferon regulatory factor-4 (IRF-4) is a hematopoietic cell-restricted transcription factor important for hematopoietic development and immune response regulation. It was also originally identified as the product of a proto-oncogene involved in chromosomal translocations in multiple myeloma. In contrast to its oncogenic function in late stages of B lymphopoiesis, expression of IRF-4 is down-regulated in certain myeloid and early B-lymphoid malignancies. In this study, we found that the IRF-4 protein levels are increased in lymphoblastic cells transformed by the BCR/ABL oncogene in response to BCR/ABL tyrosine kinase inhibitor imatinib. We further found that IRF-4 deficiency enhances BCR/ABL transformation of B-lymphoid progenitors in vitro and accelerates disease progression of BCR/ABL-induced acute B-lymphoblastic leukemia (B-ALL) in mice, whereas forced expression of IRF-4 potently suppresses BCR/ABL transformation of B-lymphoid progenitors in vitro and BCR/ABL-induced B-ALL in vivo. Further analysis showed that IRF-4 inhibits growth of BCR/ABL+ B lymphoblasts primarily through negative regulation of cell-cycle progression. These results demonstrate that IRF-4 functions as tumor suppressor in early B-cell development and may allow elucidation of new molecular pathways significant to the lymphoid leukemogenesis by BCR/ABL. The context dependent roles of IRF-4 in oncogenesis should be an important consideration in developing cancer therapies targeting IRF-4.
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Affiliation(s)
- Jaime Acquaviva
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454-9110, USA
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25
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Su W, Gordon JN, Barone F, Boursier L, Turnbull W, Mendis S, Dunn-Walters DK, Spencer J. Lambda light chain revision in the human intestinal IgA response. THE JOURNAL OF IMMUNOLOGY 2008; 181:1264-71. [PMID: 18606680 DOI: 10.4049/jimmunol.181.2.1264] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Revision of Ab L chains by secondary rearrangement in mature B cells has the potential to change the specific target of the immune response. In this study, we show for the first time that L chain revision is normal and widespread in the largest Ab producing population in man: intestinal IgA plasma cells (PC). Biases in the productive and non-productive repertoire of lambda L chains, identification of the circular products of rearrangement that have the characteristic biases of revision, and identification of RAG genes and protein all reflect revision during normal intestinal IgA PC development. We saw no evidence of IgH revision, probably due to inappropriately orientated recombination signal sequences, and little evidence of kappa-chain revision, probably due to locus inactivation by the kappa-deleting element. We propose that the lambda L chain locus is available and a principal modifier and diversifier of Ab specificity in intestinal IgA PCs.
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Affiliation(s)
- Wen Su
- Department of Immunobiology, Kings College London School of Medicine, Guy's King's College, St Thomas' Hospitals, London, United Kingdom
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26
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Vela JL, Aït-Azzouzene D, Duong BH, Ota T, Nemazee D. Rearrangement of mouse immunoglobulin kappa deleting element recombining sequence promotes immune tolerance and lambda B cell production. Immunity 2008; 28:161-70. [PMID: 18261939 DOI: 10.1016/j.immuni.2007.12.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 11/16/2007] [Accepted: 12/10/2007] [Indexed: 12/11/2022]
Abstract
The recombining sequence (RS) of mouse and its human equivalent, the immunoglobulin (Ig) kappa deleting element (IGKDE), are sequences found at the 3' end of the Ig kappa locus (Igk) that rearrange to inactivate Igk in developing B cells. RS recombination correlates with Ig lambda (Iglambda) light (L) chain expression and likely plays a role in receptor editing by eliminating Igk genes encoding autoantibodies. A mouse strain was generated in which the recombination signal of RS was removed, blocking RS-mediated Igk inactivation. In RS mutant mice, receptor editing and self-tolerance were impaired, in some cases leading to autoantibody formation. Surprisingly, mutant mice also made fewer B cells expressing lambda chain, whereas lambda versus kappa isotype exclusion was only modestly affected. These results provide insight into the mechanism of L chain isotype exclusion and indicate that RS has a physiological role in promoting the formation of lambda L chain-expressing B cells.
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MESH Headings
- Animals
- Antibodies, Antinuclear/blood
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Gene Rearrangement, B-Lymphocyte, Light Chain/genetics
- Gene Rearrangement, B-Lymphocyte, Light Chain/immunology
- Genes, Immunoglobulin
- Hybridomas
- Immune Tolerance
- Immunoglobulin kappa-Chains/genetics
- Immunoglobulin kappa-Chains/immunology
- Immunoglobulin lambda-Chains/genetics
- Immunoglobulin lambda-Chains/immunology
- Immunoglobulin lambda-Chains/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mice, Transgenic
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-2
- Recombination, Genetic
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Affiliation(s)
- José Luis Vela
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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27
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Sjakste NI, Sjakste TG. Possible involvement of DNA breaks in epigenetic regulation of cell differentiation. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407050018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Xin-Sheng Y, Zheng-Jun X, Li M, Wan-Bang S, Wei-Yang Z, Qian W, Zhi-Ming H, Min-Jie M, Ying L, Zhen-Qiang W, Xiao-Wei H, Ju-Fang W, Xiao-Ning W. Analysis of the CDR3 region of alpha/beta T-cell receptors (TCRs) and TCR BD gene double-stranded recombination signal sequence breaks end in peripheral blood mononuclear cells of T-lineage acute lymphoblastic leukemia. ACTA ACUST UNITED AC 2007; 28:405-15. [PMID: 17105495 DOI: 10.1111/j.1365-2257.2006.00827.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, numerous reports have highlighted the restriction of the CDR3 length of T-cell receptor (TCR) beta chain in T-cells infiltrating solid tumors and hematological malignancies. However, these studies ignored the restriction of CDR3 length of TCR alpha chain and few of them attempted to reveal the mechanisms of the oligo-clonal expansion of T cells in the tumors. The primary aims of this study were twofold to: (i) analyze the CDR3 length of TCR alpha and beta chain in peripheral blood mononuclear cells of T-lineage acute lymphoblastic leukemia (T-ALL); and (ii) discover the relationship between the clonality of T cells and the process of TCR rearrangement in peripheral T cells. To this end, we investigated the TCR BV and TCR AV family spectratypes of two T-ALL patients and healthy controls using the immunoscope spectratyping technique. We found that the spectratypes exhibited a Gaussian distribution in healthy controls. However, the TCR repertoires of the two patients were highly restricted in the number of different TCR BV and TCR AV family members present. Furthermore, we found that the peripheral blood mononuclear cells (PBMC) of two T-ALL patients had the recombination signal sequence (RSS) 5'- and 3'-breaks end in the TCR BD2 gene using a specialized ligation-mediated polymerase chain reaction, implying the ongoing recombination of the TCR beta gene. Analysis of the particular CDR3 length of TCR alpha/beta T cells might be helpful for further study of the individualized therapy of T-ALL. This information will also be helpful in exploring new immunological pathogenesis and facilitating the design of a T-ALL vaccine, as well as in improving our understanding of healthy human T-cell development.
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MESH Headings
- Adolescent
- Adult
- Case-Control Studies
- Cells, Cultured
- Clone Cells
- Complementarity Determining Regions/genetics
- Genes, T-Cell Receptor alpha/genetics
- Genes, T-Cell Receptor beta/genetics
- Humans
- Leukemia-Lymphoma, Adult T-Cell/blood
- Leukemia-Lymphoma, Adult T-Cell/genetics
- Leukemia-Lymphoma, Adult T-Cell/immunology
- Male
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Recombination, Genetic
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Affiliation(s)
- Y Xin-Sheng
- Institute of Molecular Immunology, Southern Medical University, Guangzhou 510515, China
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29
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Abstract
The specificities of lymphocytes for antigen are generated by a quasi-random process of gene rearrangement that often results in non-functional or autoreactive antigen receptors. Regulation of lymphocyte specificities involves not only the elimination of cells that display 'unsuitable' receptors for antigen but also the active genetic correction of these receptors by secondary recombination of the DNA. As I discuss here, an important mechanism for the genetic correction of antigen receptors is ongoing recombination, which leads to receptor editing. Receptor editing is probably an adaptation that is necessitated by the high probability of receptor autoreactivity. In both B cells and T cells, the genes that encode the two chains of the antigen receptor seem to be specialized to promote, on the one hand, the generation of diverse specificities and, on the other hand, the regulation of these specificities through efficient editing.
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Affiliation(s)
- David Nemazee
- Department of Immunology, The Scripps Research Institute, Mail Drop IMM-29, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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30
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Hsu E, Criscitiello MF. Diverse immunoglobulin light chain organizations in fish retain potential to revise B cell receptor specificities. THE JOURNAL OF IMMUNOLOGY 2006; 177:2452-62. [PMID: 16888007 PMCID: PMC3129705 DOI: 10.4049/jimmunol.177.4.2452] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have characterized the genomic organization of the three zebrafish L chain isotypes and found they all differed from those reported in other teleost fishes. Two of the zebrafish L chain isotypes are encoded by two loci, each carrying multiple V gene segments. To understand the derivation of these L chain genes and their organizations, we performed phylogenetic analyses and show that IgL organization can diverge considerably among closely related species. Except in zebrafish, the teleost fish IgL each contain only two to four recombinogenic components (one to three V, one J) and exist in multiple copies. BCR heterogeneity can be generated, but this arrangement apparently provides neither combinatorial diversification nor an opportunity for the secondary rearrangements that, in mammals, take place during receptor editing, a process crucial to the promotion of tolerance in developing lymphocytes. Examination of the zebrafish IgL recombination possibilities gave insight into how the suppression of self-reactivity by receptor editing might be managed, including in miniloci. We suggest that, despite the diverse IgL organizations in early and higher vertebrates, two elements essential to generating the Ab repertoire are retained: the numerous genes/loci for ligand-binding diversification and the potential for correcting unwanted specificities that arise.
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Affiliation(s)
- Ellen Hsu
- Department of Physiology and Pharmacology, State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203, USA.
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31
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Sprangers M, Feldhahn N, Liedtke S, Jumaa H, Siebert R, Müschen M. SLP65 deficiency results in perpetual V(D)J recombinase activity in pre-B-lymphoblastic leukemia and B-cell lymphoma cells. Oncogene 2006; 25:5180-6. [PMID: 16636677 DOI: 10.1038/sj.onc.1209520] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Perpetual V(D)J recombinase activity involving multiple DNA double-strand break events in B-cell lineage leukemia and lymphoma cells may introduce secondary genetic aberrations leading towards malignant progression. Here, we investigated defective negative feedback signaling through the (pre-) B-cell receptor as a possible reason for deregulated V(D)J recombinase activity in B-cell malignancy. On studying 28 cases of pre-B-lymphoblastic leukemia and 27 B-cell lymphomas, expression of the (pre-) B-cell receptor-related linker molecule SLP65 (SH2 domain-containing lymphocyte protein of 65 kDa) was found to be defective in seven and five cases, respectively. SLP65 deficiency correlates with RAG1/2 expression and unremitting V(H) gene rearrangement activity. Reconstitution of SLP65 expression in SLP65-deficient leukemia and lymphoma cells results in downregulation of RAG1/2 expression and prevents both de novo V(H)-DJ(H) rearrangements and secondary V(H) replacement. We conclude that iterative V(H) gene rearrangement represents a frequent feature in B-lymphoid malignancy, which can be attributed to SLP65 deficiency in many cases.
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Affiliation(s)
- M Sprangers
- Laboratory for Molecular Stem Cell Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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32
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Klein F, Feldhahn N, Herzog S, Sprangers M, Mooster JL, Jumaa H, Müschen M. BCR-ABL1 induces aberrant splicing of IKAROS and lineage infidelity in pre-B lymphoblastic leukemia cells. Oncogene 2006; 25:1118-24. [PMID: 16205638 DOI: 10.1038/sj.onc.1209133] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pre-B lymphoblastic leukemia cells carrying a BCR-ABL1 gene rearrangement exhibit an undifferentiated phenotype. Comparing the genome-wide gene expression profiles of normal B-cell subsets and BCR-ABL1+ pre-B lymphoblastic leukemia cells by SAGE, the leukemia cells show loss of B lymphoid identity and aberrant expression of myeloid lineage-specific molecules. Consistent with this, BCR-ABL1+ pre-B lymphoblastic leukemia cells exhibit defective expression of IKAROS, a transcription factor needed for early lymphoid lineage commitment. As shown by inducible expression of BCR-ABL1 in human and murine B-cell precursor cell lines, BCR-ABL1 induces the expression of a dominant-negative IKAROS splice variant, termed IK6. Comparing matched leukemia sample pairs from patients before and during therapy with the BCR-ABL1 kinase inhibitor STI571 (Imatinib), inhibition of BCR-ABL1 partially corrected aberrant expression of IK6 and lineage infidelity of the leukemia cells. To elucidate the contribution of IK6 to lineage infidelity in BCR-ABL1+ cell lines, IK6 expression was silenced by RNA interference. Upon inhibition of IK6, BCR-ABL1+ leukemia cells partially restored B lymphoid lineage commitment. Therefore, we propose that BCR-ABL1 induces aberrant splicing of IKAROS, which interferes with lineage identity and differentiation of pre-B lymphoblastic leukemia cells.
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Affiliation(s)
- F Klein
- Laboratory for Molecular Stem Cell Biology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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Feldhahn N, Río P, Soh BNB, Liedtke S, Sprangers M, Klein F, Wernet P, Jumaa H, Hofmann WK, Hanenberg H, Rowley JD, Müschen M. Deficiency of Bruton's tyrosine kinase in B cell precursor leukemia cells. Proc Natl Acad Sci U S A 2005; 102:13266-71. [PMID: 16141323 PMCID: PMC1201599 DOI: 10.1073/pnas.0505196102] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bruton's tyrosine kinase (BTK) deficiency results in a differentiation block at the pre-B cell stage. Likewise, acute lymphoblastic leukemia cells are typically arrested at early stages of B cell development. We therefore investigated BTK function in B cell precursor leukemia cells carrying a BCR-ABL1, E2A-PBX1, MLL-AF4, TEL-AML1, or TEL-PDGFRB gene rearrangement. Although somatic mutations of the BTK gene are rare in B cell precursor leukemia cells, we identified kinase-deficient splice variants of BTK throughout all leukemia subtypes. Unlike infant leukemia cells carrying an MLL-AF4 gene rearrangement, where expression of full-length BTK was detectable in only four of eight primary cases, in leukemia cells harboring other fusion genes full-length BTK was typically coexpressed with kinase-deficient variants. As shown by overexpression experiments, kinase-deficient splice variants can act as a dominant-negative BTK in that they suppress BTK-dependent differentiation and pre-B cell receptor responsiveness of the leukemia cells. On the other hand, induced expression of full-length BTK rendered the leukemia cells particularly sensitive to apoptosis. Comparing BTK expression in surviving or preapoptotic leukemia cells after 10-Gy gamma radiation, we observed selective survival of leukemia cells that exhibit expression of dominant-negative BTK forms. These findings indicate that lack of BTK expression or expression of dominant-negative splice variants in B cell precursor leukemia cells can (i) inhibit differentiation beyond the pre-B cell stage and (ii) protect from radiation-induced apoptosis.
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Affiliation(s)
- Niklas Feldhahn
- Laboratory for Molecular Stem Cell Biology, Institute for Transplantation Diagnostics and Cell Therapeutics, and Department of Pediatric Hematology and Oncology, Children's Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany
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Soh BNB, Klein F, Feldhahn N, Müschen M. B-lymphoid or myeloid lineage identity of cell lines derived from chronic myeloid leukemia blast crisis. ACTA ACUST UNITED AC 2005; 161:187-8. [PMID: 16102593 DOI: 10.1016/j.cancergencyto.2005.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 02/17/2005] [Indexed: 11/23/2022]
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