1
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Glynn RA, Hayer KE, Bassing CH. ATM-dependent Phosphorylation of Nemo SQ Motifs Is Dispensable for Nemo-mediated Gene Expression Changes in Response to DNA Double-Strand Breaks. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 213:628-640. [PMID: 39007641 PMCID: PMC11348802 DOI: 10.4049/jimmunol.2300139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 06/25/2024] [Indexed: 07/16/2024]
Abstract
In response to DNA double-strand breaks (DSBs), the ATM kinase activates NF-κB factors to stimulate gene expression changes that promote survival and allow time for cells to repair damage. In cell lines, ATM can activate NF-κB transcription factors via two independent, convergent mechanisms. One is ATM-mediated phosphorylation of nuclear NF-κB essential modulator (Nemo) protein, which leads to monoubiquitylation and export of Nemo to the cytoplasm where it engages the IκB kinase (IKK) complex to activate NF-κB. Another is DSB-triggered migration of ATM into the cytoplasm, where it promotes monoubiquitylation of Nemo and the resulting IKK-mediated activation of NF-κB. ATM has many other functions in the DSB response beyond activation of NF-κB, and Nemo activates NF-κB downstream of diverse stimuli, including developmental or proinflammatory stimuli such as LPSs. To elucidate the in vivo role of DSB-induced, ATM-dependent changes in expression of NF-κB-responsive genes, we generated mice expressing phosphomutant Nemo protein lacking consensus SQ sites for phosphorylation by ATM or related kinases. We demonstrate that these mice are viable/healthy and fertile and exhibit overall normal B and T lymphocyte development. Moreover, treatment of their B lineage cells with LPS induces normal NF-κB-regulated gene expression changes. Furthermore, in marked contrast to results from a pre-B cell line, primary B lineage cells expressing phosphomutant Nemo treated with the genotoxic drug etoposide induce normal ATM- and Nemo-dependent changes in expression of NF-κB-regulated genes. Our data demonstrate that ATM-dependent phosphorylation of Nemo SQ motifs in vivo is dispensable for DSB-signaled changes in expression of NF-κB-regulated genes.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Katharina E. Hayer
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Biomedical Engineering Doctoral Degree Program, School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, 19104
- Department of Biomedical and Health Informatics, Children’s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA, 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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2
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Ochodnicka-Mackovicova K, Mokry M, Haagmans M, Bradley TE, van Noesel CJM, Guikema JEJ. RAG1/2 induces double-stranded DNA breaks at non-Ig loci in the proximity of single sequence repeats in developing B cells. Eur J Immunol 2024:e2350958. [PMID: 39046890 DOI: 10.1002/eji.202350958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 07/11/2024] [Accepted: 07/16/2024] [Indexed: 07/27/2024]
Abstract
In developing B cells, V(D)J gene recombination is initiated by the RAG1/2 endonuclease complex, introducing double-stranded DNA breaks (DSBs) in V, D, and J genes and resulting in the formation of the hypervariable parts of immunoglobulins (Ig). Persistent or aberrant RAG1/2 targeting is a potential threat to genome integrity. While RAG1 and RAG2 have been shown to bind various regions genome-wide, the in vivo off-target DNA damage instigated by RAG1/2 endonuclease remains less well understood. In the current study, we identified regions containing RAG1/2-induced DNA breaks in mouse pre-B cells on a genome-wide scale using a global DNA DSB detection strategy. We detected 1489 putative RAG1/2-dependent DSBs, most of which were located outside the Ig loci. DNA sequence motif analysis showed a specific enrichment of RAG1/2-induced DNA DSBs at GA- and CA-repeats and GC-rich motifs. These findings provide further insights into RAG1/2 off-target activity. The ability of RAG1/2 to introduce DSBs on the non-Ig loci during the endogenous V(D)J recombination emphasizes its genotoxic potential in developing lymphocytes.
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Affiliation(s)
- Katarina Ochodnicka-Mackovicova
- Department of Pathology, Amsterdam University Medical Center, Location AMC, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam, The Netherlands
| | - Michal Mokry
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Central Diagnostics Laboratory, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Martin Haagmans
- Core Facility Genomics, Department of Clinical Genetics, Amsterdam University Medical Center, The Netherlands
| | - Ted E Bradley
- Core Facility Genomics, Department of Clinical Genetics, Amsterdam University Medical Center, The Netherlands
| | - Carel J M van Noesel
- Department of Pathology, Amsterdam University Medical Center, Location AMC, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam, The Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Amsterdam University Medical Center, Location AMC, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam, The Netherlands
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3
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Naik AK, Dauphars DJ, Corbett E, Simpson L, Schatz DG, Krangel MS. RORγt up-regulates RAG gene expression in DP thymocytes to expand the Tcra repertoire. Sci Immunol 2024; 9:eadh5318. [PMID: 38489350 PMCID: PMC11005092 DOI: 10.1126/sciimmunol.adh5318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 02/21/2024] [Indexed: 03/17/2024]
Abstract
Recombination activating gene (RAG) expression increases as thymocytes transition from the CD4-CD8- double-negative (DN) to the CD4+CD8+ double-positive (DP) stage, but the physiological importance and mechanism of transcriptional up-regulation are unknown. Here, we show that a DP-specific component of the recombination activating genes antisilencer (DPASE) provokes elevated RAG expression in DP thymocytes. Mouse DP thymocytes lacking the DPASE display RAG expression equivalent to that in DN thymocytes, but this supports only a partial Tcra repertoire due to inefficient secondary Vα-Jα rearrangement. These data indicate that RAG up-regulation is required for a replete Tcra repertoire and that RAG expression is fine-tuned during lymphocyte development to meet the requirements of distinct antigen receptor loci. We further show that transcription factor RORγt directs RAG up-regulation in DP thymocytes by binding to the DPASE and that RORγt influences the Tcra repertoire by binding to the Tcra enhancer. These data, together with prior work showing RORγt to control Tcra rearrangement by regulating DP thymocyte proliferation and survival, reveal RORγt to orchestrate multiple pathways that support formation of the Tcra repertoire.
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Affiliation(s)
- Abani Kanta Naik
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - Danielle J Dauphars
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - Elizabeth Corbett
- Department of Immunobiology and Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Lunden Simpson
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - David G Schatz
- Department of Immunobiology and Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Michael S Krangel
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
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4
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Khan GH, Veltkamp F, Scheper M, Hoebe RA, Claessen N, Butter L, Bouts AHM, Florquin S, Guikema JEJ. Levamisole suppresses activation and proliferation of human T cells by the induction of a p53-dependent DNA damage response. Eur J Immunol 2023; 53:e2350562. [PMID: 37597325 DOI: 10.1002/eji.202350562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/17/2023] [Accepted: 08/18/2023] [Indexed: 08/21/2023]
Abstract
Levamisole (LMS) is a small molecule used in the treatment of idiopathic nephrotic syndrome (INS). The pathogenesis of INS remains unknown, but evidence points toward an immunological basis of the disease. Recently, LMS has been shown to increase the relapse-free survival in INS patients. While LMS has been hypothesized to exert an immunomodulatory effect, its mechanism of action remains unknown. Here, we show that LMS decreased activation and proliferation of human T cells. T-cell activation-associated cytokines such as IL-2, TNF-α, and IFN-γ were reduced upon LMS treatment, whereas IL-4 and IL-13 were increased. Gene expression profiling confirmed that the suppressive effects of LMS as genes involved in cell cycle progression were downregulated. Furthermore, genes associated with p53 activation were upregulated by LMS. In agreement, LMS treatment resulted in p53 phosphorylation and increased expression of the p53 target gene FAS. Accordingly, LMS sensitized activated T cells for Fas-mediated apoptosis. LMS treatment resulted in a mid-S phase cell cycle arrest accompanied by γH2AX-foci formation and phosphorylation of CHK1. Our findings indicate that LMS acts as an immunosuppressive drug that directly affects the activation and proliferation of human T cells by induction of DNA damage and the activation of a p53-dependent DNA damage response.
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Affiliation(s)
- Gerarda H Khan
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Floor Veltkamp
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Mirte Scheper
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ron A Hoebe
- Department of Medical Biology, Amsterdam UMC and Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Nike Claessen
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Loes Butter
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Antonia H M Bouts
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Sandrine Florquin
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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5
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Glynn RA, Bassing CH. Nemo-Dependent, ATM-Mediated Signals from RAG DNA Breaks at Igk Feedback Inhibit V κ Recombination to Enforce Igκ Allelic Exclusion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:371-383. [PMID: 34965965 PMCID: PMC8756740 DOI: 10.4049/jimmunol.2100696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/01/2021] [Indexed: 01/17/2023]
Abstract
Monoallelic AgR gene expression underlies specific adaptive immune responses. AgR allelic exclusion is achieved by sequential initiation of V(D)J recombination between alleles and resultant protein from one allele signaling to prevent recombination of the other. The ATM kinase, a regulator of the DNA double-strand break (DSB) response, helps enforce allelic exclusion through undetermined mechanisms. ATM promotes repair of RAG1/RAG2 (RAG) endonuclease-induced DSBs and transduces signals from RAG DSBs during Igk gene rearrangement on one allele to transiently inhibit RAG1 protein expression, Igk accessibility, and RAG cleavage of the other allele. Yet, the relative contributions of ATM functions in DSB repair versus signaling to enforce AgR allelic exclusion remain undetermined. In this study, we demonstrate that inactivation in mouse pre-B cells of the NF-κB essential modulator (Nemo) protein, an effector of ATM signaling, diminishes RAG DSB-triggered repression of Rag1/Rag2 transcription and Igk accessibility but does not result in aberrant repair of RAG DSBs like ATM inactivation. We show that Nemo deficiency increases simultaneous biallelic Igk cleavage in pre-B cells and raises the frequency of B cells expressing Igκ proteins from both alleles. In contrast, the incidence of biallelic Igκ expression is not elevated by inactivation of the SpiC transcriptional repressor, which is induced by RAG DSBs in an ATM-dependent manner and suppresses Igk accessibility. Thus, we conclude that Nemo-dependent, ATM-mediated DNA damage signals enforce Igκ allelic exclusion by orchestrating transient repression of RAG expression and feedback inhibition of additional Igk rearrangements in response to RAG cleavage on one Igk allele.
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Affiliation(s)
- Rebecca A. Glynn
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104
| | - Craig H. Bassing
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104,Department of Pathology and Laboratory Medicine, Children’s Hospital of Pennsylvania, Philadelphia, PA 19104,Corresponding Author: Craig H. Bassing, Ph.D., Children’s Hospital of Philadelphia, 4054 Colket Translational Research Building, 3501 Civic Center Blvd., Philadelphia, PA 19104, 267-426-0311,
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6
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Maartens M, Kruger MJ, van de Vyver M. The Effect of N-Acetylcysteine and Ascorbic Acid-2-Phosphate Supplementation on Mesenchymal Stem Cell Function in B6.C-Lep ob/J Type 2 Diabetic Mice. Stem Cells Dev 2021; 30:1179-1189. [PMID: 34544266 DOI: 10.1089/scd.2021.0139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diabetes is a complex multifactorial disorder associated with hyperglycemia, oxidative stress, and inflammation. The pathological microenvironment impairs mesenchymal stem cell (MSC) viability and dysregulates their proregenerative and immune-modulatory function causing maladaptive tissue damage. Targeting stem cells to protect them against impairment could thus delay the onset of complications and enhance the quality of life in diabetes mellitus patients. The aim of this study was to investigate the efficacy of N-acetylcysteine (NAC) and ascorbic-acid-2-phosphate (AAP) oral supplementation as preventative measure against MSC impairment. Healthy wild-type control (C57BL/6J) (male, n = 24) and obese diabetic (B6.C-Lepob/J) (ob/ob) (male, n = 24) mice received either placebo or antioxidant (NAC/AAP) supplementation for a period of 6 weeks. Metabolic parameters (weight and blood glucose) and the oxidative status (serum total serum antioxidant capacity, malondialdehyde) of animals were assessed. At the end of the 6-week supplementation period, bone marrow MSCs were isolated and their functionality (growth rate, viability, adipogenesis, and osteogenesis) assessed ex vivo. Real time quantitative polymerase chain reaction microarray analysis was also performed to assess the expression of 84 genes related to oxidative stress in MSCs. Despite no change in the metabolic profile, NAC/AAP supplementation improved the antioxidant status of diabetic animals and reduced lipid peroxidation, which is indicative of cellular damage. NAC/AAP also improved the population doubling time of MSCs (first 6-days postisolation) and significantly downregulated the expression of two genes (Nox1 and Rag2) associated with oxidative stress compared to placebo treatment. Taken together, this study has shown reduced oxidative stress and improvements in MSC function following in vivo antioxidant supplementation in healthy control and type 2 diabetic mice.
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Affiliation(s)
- Michelle Maartens
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Maria Jacoba Kruger
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Mari van de Vyver
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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7
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Zhu Y, Lin B, Ding F, Ma F, Zhou X, Zong H, Feng G, Chen Q, Chen G, Lv X. Leonurine negatively modulates T cells activity by suppressing recombination activation gene protein 2 in pulmonary fibrosis. EUR J INFLAMM 2021. [DOI: 10.1177/20587392211035907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Introduction The key transformed T cell transcription factor recombination activation gene protein 2 (RAG2) is regulated during inflammation to allow for the acquisition of effector T cells functions. The present study was designed to investigate whether stress signals elicited by leonurine (LEO) could lead to the degradation of RAG2 through v-akt murine thymoma viral oncogene homolog (AKT) signaling in lung fibrosis. Methods A total of 120 female mice were randomly divided into five groups (Group I–V): Normal group, bleomycin (BLM), BLM+LEO 50 mg/kg/d, BLM+LEO 100 mg/kg/d, and BLM+LEO 50 mg/kg/d+LY294002. Hematoxylin-eosin, Masson’s, and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining were performed to observe the pathomorphological changes. The expression of CD3+, TGF-β, RAG2, and Bcl proteins was examined by immunodetection, while that of E-cadherin (ECAD), AKT, TGF-β1, alpha-actin-2, Bax, and RAG2 was detected by Western blot analysis. Results The level of T lymphocytes was reduced sharply in LEO-treated mice as compared to the other groups. The AKT signal was greatly inhibited in the BLM group and activated with LEO treatment on day 14. In addition, RAG2 was attenuated by LEO on day 14 and day 28. LY294002 could reverse the expression of AKT and RAG2 on day 28. Remarkably, the low dose of LEO has a greater protective efficacy as compared to the high-dose LEO group in terms of pulmonary fibrosis, T cell inactivation, and apoptosis in alveolar cells. Conclusion The results of the present study suggested that LEO has a protective effect on lung fibrosis with possible mechanisms of attenuating apoptosis and inflammation via the upregulation of the AKT signal in transformed T cells by suppressing the expression and activity of RAG2.
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Affiliation(s)
- Yongping Zhu
- Department of Cardiovascular Surgery, Fujian Medical University Attached Union Hospital, Fuzhou, Fujian, China
| | - Bixia Lin
- Department of Pharmacy, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Fadian Ding
- Department of Hepatopancreatobiliary Surgery and Institute of Abdominal Surgery, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Fenfen Ma
- Department of Pharmacy, Shanghai Pudong Hospital, Fudan University, Shanghai, China
| | - Xiaohui Zhou
- Department of Clinical Skill Training Center, Fujian Medical University, Fuzhou, Fujian, China
| | - Haiyang Zong
- Department of Orthopedic Surgery, The 920 Hospital of the Joint Logistic Support Force, Kunming, Yunnan, China
| | - Gao Feng
- Department of Pathology, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
| | - Qingquan Chen
- Department of Laboratory Medicine, Fujian Medical University, Fuzhou, China
| | - Gongping Chen
- Department of Respiratory and Critical Care Medicine, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
- Institute of Respiratory Disease, Fujian Medical University, Fuzhou, Fujian, China
| | - Xiaoting Lv
- Department of Respiratory and Critical Care Medicine, 1st Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China
- Institute of Respiratory Disease, Fujian Medical University, Fuzhou, Fujian, China
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8
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Jia C, Wang Q, Yao X, Yang J. The Role of DNA Damage Induced by Low/High Dose Ionizing Radiation in Cell Carcinogenesis. EXPLORATORY RESEARCH AND HYPOTHESIS IN MEDICINE 2021; 000:000-000. [DOI: 10.14218/erhm.2021.00020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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9
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Ioniţă E, Marcu A, Temelie M, Savu D, Şerbănescu M, Ciubotaru M. Radiofrequency EMF irradiation effects on pre-B lymphocytes undergoing somatic recombination. Sci Rep 2021; 11:12651. [PMID: 34135382 PMCID: PMC8208969 DOI: 10.1038/s41598-021-91790-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/31/2021] [Indexed: 01/14/2023] Open
Abstract
Intense electromagnetic fields (EMFs) induce DNA double stranded breaks (DSBs) in exposed lymphocytes.We study developing pre-B lymphocytes following V(D)J recombination at their Immunoglobulin light chain loci (IgL). Recombination physiologically induces DNA DSBs, and we tested if low doses of EMF irradiation affect this developmental stage. Recombining pre-B cells, were exposed for 48 h to low intensity EMFs (maximal radiative power density flux S of 9.5 µW/cm2 and electric field intensity 3 V/m) from waves of frequencies ranging from 720 to 1224 MHz. Irradiated pre-B cells show decreased levels of recombination, reduction which is dependent upon the power dose and most remarkably upon the frequency of the applied EMF. Although 50% recombination reduction cannot be obtained even for an S of 9.5 µW/cm2 in cells irradiated at 720 MHz, such an effect is reached in cells exposed to only 0.45 µW/cm2 power with 950 and 1000 MHz waves. A maximal four-fold recombination reduction was measured in cells exposed to 1000 MHz waves with S from 0.2 to 4.5 µW/cm2 displaying normal levels of γH2AX phosphorylated histone. Our findings show that developing B cells exposure to low intensity EMFs can affect the levels of production and diversity of their antibodies repertoire.
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Affiliation(s)
- Elena Ioniţă
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania.,Department of Immunology, Internal Medicine, Colentina Clinical Hospital, 72202, Bucharest, Romania
| | - Aurelian Marcu
- Center for Advanced Laser Technologies, National Institute for Laser Plasma and Radiation Physics, 077125, Măgurele, Ilfov, Romania
| | - Mihaela Temelie
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania
| | - Diana Savu
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania
| | - Mihai Şerbănescu
- Center for Advanced Laser Technologies, National Institute for Laser Plasma and Radiation Physics, 077125, Măgurele, Ilfov, Romania
| | - Mihai Ciubotaru
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania. .,Department of Immunology, Internal Medicine, Colentina Clinical Hospital, 72202, Bucharest, Romania.
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10
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AKT signaling restrains tumor suppressive functions of FOXO transcription factors and GSK3 kinase in multiple myeloma. Blood Adv 2021; 4:4151-4164. [PMID: 32898245 DOI: 10.1182/bloodadvances.2019001393] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023] Open
Abstract
The phosphatidylinositide-3 kinases and the downstream mediator AKT drive survival and proliferation of multiple myeloma (MM) cells. AKT signaling is active in MM and has pleiotropic effects; however, the key molecular aspects of AKT dependency in MM are not fully clear. Among the various downstream AKT targets are the Forkhead box O (FOXO) transcription factors (TFs) and glycogen synthase kinase 3 (GSK3), which are negatively regulated by AKT signaling. Here we show that abrogation of AKT signaling in MM cells provokes cell death and cell cycle arrest, which crucially depends on both FOXO TFs and GSK3. Based on gene expression profiling, we defined a FOXO-repressed gene set that has prognostic significance in a large cohort of patients with MM, indicating that AKT-mediated gene activation is associated with inferior overall survival. We further show that AKT signaling stabilizes the antiapoptotic myeloid cell leukemia 1 (MCL1) protein by inhibiting FOXO- and GSK3-mediated MCL1 turnover. In concordance, abrogation of AKT signaling greatly sensitized MM cells for an MCL1-targeting BH3-mimetic, which is currently in clinical development. Taken together, our results indicate that AKT activity is required to restrain the tumor-suppressive functions of FOXO and GSK3, thereby stabilizing the antiapoptotic protein MCL1 in MM. These novel insights into the role of AKT in MM pathogenesis and MCL1 regulation provide opportunities to improve targeted therapy for patients with MM.
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11
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Byrum JN, Hoolehan WE, Simpson DA, Rodgers W, Rodgers KK. Full length RAG2 expression enhances the DNA damage response in pre-B cells. Immunobiology 2021; 226:152089. [PMID: 33873062 DOI: 10.1016/j.imbio.2021.152089] [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: 12/22/2020] [Revised: 03/15/2021] [Accepted: 03/24/2021] [Indexed: 11/30/2022]
Abstract
V(D)J recombination by the RAG1 and RAG2 protein complex in developing lymphocytes includes DNA double strand break (DSB) intermediates. RAG2 undergoes export from the nucleus and enrichment at the centrosome minutes following production of DSBs by genotoxic stress, suggesting that RAG2 participates in cellular responses to DSBs such as those generated during V(D)J recombination. To determine the effect of RAG2 expression on cell viability following DSB generation, we measured pre-B cells that expressed either full length (FL) wild-type RAG2, or a T490A mutant of RAG2 that has increased stability and fails to undergo nuclear export following generation of DSBs. Each RAG2 construct was labeled with GFP at the N-terminus. Compared to the T490A mutant, cells expressing FL RAG2 exhibited elevated apoptosis by 24 h following irradiation, and this coincided with a greater amount of Caspase 3 cleavage measured in cell lysates. Pre-B cells expressing either RAG2 protein exhibited similar increases in phospho-p53 levels following irradiation. Interestingly, FL RAG2-expressing cells exhibited elevated division relative to the T490A clone beginning ~24 h following irradiation, as well as an increased percentage of cells proceeding through mitosis, suggesting an improved rate of recovery following the initial burst in apoptosis. Altogether, these data show that FL RAG2, but not its stable nuclear export-defective T490A mutant, participates in pre-B cell decisions between apoptosis versus DNA repair and cell cycle progression following DNA damage.
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Affiliation(s)
- Jennifer N Byrum
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, United States
| | - Walker E Hoolehan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, United States
| | - Destiny A Simpson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, United States
| | - William Rodgers
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, United States
| | - Karla K Rodgers
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, United States.
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12
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Zhu Y, Wu L. Identification of latent core genes and pathways associated with myelodysplastic syndromes based on integrated bioinformatics analysis. ACTA ACUST UNITED AC 2021; 25:299-308. [PMID: 32772642 DOI: 10.1080/16078454.2020.1802917] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Background: Myelodysplastic syndromes (MDS) are relatively common hematological malignancies characterized by dysplastic hematopoiesis in one or more of the lineages of the bone marrow. This study aimed to identify critical pathogenic biomarkers associated with the carcinogenesis and progression of MDS. Methods: To explore the candidate genes, the expression profiles of GSE2779, GSE4619, and GSE19429 were downloaded from the Gene Expression Omnibus (GEO) database, which contained CD34+ cells isolated from MDS patients and normal controls. The three microarray datasets were integrated to obtain differentially expressed genes (DEGs) and were deeply analyzed by bioinformatics methods. The construction of protein-protein interaction (PPI) network together with module analysis was performed based on Cytoscape software and the Search Tool for the Retrieval of Interacting Genes (STRING) database. Results: Our study identified 114 DEGs, which were highly enriched in various key pathways, including forkhead box protein O (FoxO) signaling pathway, the primary immunodeficiency, and hematopoietic cell lineage. Twelve core genes, such as FOXO1, PAX5 and CXCR4 were identified with a high degree of connectivity. It is plausible that FoxO signaling pathway plays an important role in MDS, and the dysregulation of FOXO1 was significantly associated with TGFβ, IL2/STAT5, Notch signaling and apoptosis pathways. Conclusion: The current study for the first time identified twelve latent indicators and their downstream targets, which might become significant biomarkers for worse clinical characteristics in MDS.
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Affiliation(s)
- Yuqian Zhu
- Department of Hematology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, People's Republic of China
| | - Lingyun Wu
- Department of Hematology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, People's Republic of China
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13
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Jani PK, Kubagawa H, Melchers F. A rheostat sets B-cell receptor repertoire selection to distinguish self from non-self. Curr Opin Immunol 2020; 67:42-49. [PMID: 32916645 DOI: 10.1016/j.coi.2020.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022]
Abstract
In bone marrow VDJ-recombination continuously generates original repertoires of immature B cells expressing IgM-B cell receptor (BcR), in which each cell recognizes the wide variety of self and non-self antigens with an individually different spectrum of avidities. High avidity self-reactive B cells try to edit their BcRs by secondary or multiple VL-rearrangements to JL-rearrangements. If they do not manage to change their self reactivity, they are deleted by apoptosis. Low avidity self-reactive B cells are anergized, while B cells with no avidity to self are ignored. A rheostat crosslinking antigen-binding BcRs, self antigen complexed with pentameric IgM and Fcμ-receptor monitors high, low or no binding. PI3K and PTEN are the effectors of this self antigen-sensing device. In mature B cells this rheostat continues to function in the activation of resting B cells by foreign antigens which crosslink BcR, antigen and pentameric IgM with Fcμ-receptors.
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Affiliation(s)
- Peter K Jani
- Deutsches Rheuma-Forschungszentrum, Charitéplatz 1, D-10117 Berlin, Germany.
| | - Hiromi Kubagawa
- Deutsches Rheuma-Forschungszentrum, Charitéplatz 1, D-10117 Berlin, Germany
| | - Fritz Melchers
- Deutsches Rheuma-Forschungszentrum, Charitéplatz 1, D-10117 Berlin, Germany
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14
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Chi X, Li Y, Qiu X. V(D)J recombination, somatic hypermutation and class switch recombination of immunoglobulins: mechanism and regulation. Immunology 2020; 160:233-247. [PMID: 32031242 DOI: 10.1111/imm.13176] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 12/30/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023] Open
Abstract
Immunoglobulins emerging from B lymphocytes and capable of recognizing almost all kinds of antigens owing to the extreme diversity of their antigen-binding portions, known as variable (V) regions, play an important role in immune responses. The exons encoding the V regions are known as V (variable), D (diversity), or J (joining) genes. V, D, J segments exist as multiple copy arrays on the chromosome. The recombination of the V(D)J gene is the key mechanism to produce antibody diversity. The recombinational process, including randomly choosing a pair of V, D, J segments, introducing double-strand breaks adjacent to each segment, deleting (or inverting in some cases) the intervening DNA and ligating the segments together, is defined as V(D)J recombination, which contributes to surprising immunoglobulin diversity in vertebrate immune systems. To enhance both the ability of immunoglobulins to recognize and bind to foreign antigens and the effector capacities of the expressed antibodies, naive B cells will undergo class switching recombination (CSR) and somatic hypermutation (SHM). However, the genetics mechanisms of V(D)J recombination, CSR and SHM are not clear. In this review, we summarize the major progress in mechanism studies of immunoglobulin V(D)J gene recombination and CSR as well as SHM, and their regulatory mechanisms.
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Affiliation(s)
- Xiying Chi
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China.,NHC Key Laboratory of Medical Immunology, Peking University, Beijing, China
| | - Yue Li
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China.,NHC Key Laboratory of Medical Immunology, Peking University, Beijing, China
| | - Xiaoyan Qiu
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China.,NHC Key Laboratory of Medical Immunology, Peking University, Beijing, China
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15
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Abstract
DNA damage occurs on exposure to genotoxic agents and during physiological DNA transactions. DNA double-strand breaks (DSBs) are particularly dangerous lesions that activate DNA damage response (DDR) kinases, leading to initiation of a canonical DDR (cDDR). This response includes activation of cell cycle checkpoints and engagement of pathways that repair the DNA DSBs to maintain genomic integrity. In adaptive immune cells, programmed DNA DSBs are generated at precise genomic locations during the assembly and diversification of lymphocyte antigen receptor genes. In innate immune cells, the production of genotoxic agents, such as reactive nitrogen molecules, in response to pathogens can also cause genomic DNA DSBs. These DSBs in adaptive and innate immune cells activate the cDDR. However, recent studies have demonstrated that they also activate non-canonical DDRs (ncDDRs) that regulate cell type-specific processes that are important for innate and adaptive immune responses. Here, we review these ncDDRs and discuss how they integrate with other signals during immune system development and function.
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16
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Bahjat M, de Wilde G, van Dam T, Maas C, Bloedjes T, Bende RJ, van Noesel CJM, Luijks DM, Eldering E, Kersten MJ, Guikema JEJ. The NEDD8-activating enzyme inhibitor MLN4924 induces DNA damage in Ph+ leukemia and sensitizes for ABL kinase inhibitors. Cell Cycle 2019; 18:2307-2322. [PMID: 31349760 PMCID: PMC6738521 DOI: 10.1080/15384101.2019.1646068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The BCR-ABL1 fusion gene is the driver oncogene in chronic myeloid leukemia (CML) and Philadelphia-chromosome positive (Ph+) acute lymphoblastic leukemia (ALL). The introduction of tyrosine kinase inhibitors (TKIs) targeting the ABL kinase (such as imatinib) has dramatically improved survival of CML and Ph+ ALL patients. However, primary and acquired resistance to TKIs remains a clinical challenge. Ph+ leukemia patients who achieve a complete cytogenetic (CCR) or deep molecular response (MR) (≥4.5log reduction in BCR-ABL1 transcripts) represent long-term survivors. Thus, the fast and early eradication of leukemic cells predicts MR and is the prime clinical goal for these patients. We show here that the first-in-class inhibitor of the Nedd8-activating enzyme (NAE1) MLN4924 effectively induced caspase-dependent apoptosis in Ph+ leukemia cells, and sensitized leukemic cells for ABL tyrosine kinase inhibitors (TKI) and hydroxyurea (HU). We demonstrate that MLN4924 induced DNA damage in Ph+ leukemia cells by provoking the activation of an intra S-phase checkpoint, which was enhanced by imatinib co-treatment. The combination of MLN4924 and imatinib furthermore triggered a dramatic shift in the expression of MCL1 and NOXA. Our data offers a clear rationale to explore the clinical activity of MLN4924 (alone and in combination with ABL TKI) in Ph+ leukemia patients
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Affiliation(s)
- Mahnoush Bahjat
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Guus de Wilde
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Tijmen van Dam
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Chiel Maas
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Timon Bloedjes
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Richard J Bende
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Carel J M van Noesel
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
| | - Dieuwertje M Luijks
- Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands.,Department of Experimental Immunology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands
| | - Eric Eldering
- Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands.,Department of Experimental Immunology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands
| | - Marie José Kersten
- Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands.,Department of Hematology, Amsterdam University Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Amsterdam University Medical Centers, location AMC, University of Amsterdam , Amsterdam , The Netherlands.,Lymphoma and Myeloma Center Amsterdam (LYMMCARE) , Amsterdam , The Netherlands
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17
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Han Q, Ma J, Gu Y, Song H, Kapadia M, Kawasawa YI, Dovat S, Song C, Ge Z. RAG1 high expression associated with IKZF1 dysfunction in adult B-cell acute lymphoblastic leukemia. J Cancer 2019; 10:3842-3850. [PMID: 31333801 PMCID: PMC6636280 DOI: 10.7150/jca.33989] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/30/2019] [Indexed: 12/13/2022] Open
Abstract
The recombination mediated by recombination activating gene (RAG) is not only the dominant mutational process but also the predominant driver of oncogenic genomic rearrangement in acute lymphoblastic leukemia (ALL). It is further responsible for leukemic clonal evolution. In this study, significant RAG1 increase is observed in the subsets of B-ALL patients, and high expression of RAG1 is observed to be correlated with high proliferation markers. IKZF1-encoded protein, IKAROS, directly binds to the RAG1 promoter and regulates RAG1 expression in leukemic cells. CK2 inhibitor by increasing IKAROS activity significantly suppresses RAG1 expression in ALL in an IKAROS-dependent manner. Patients with IKZF1 deletion have significantly higher expression of RAG1 compared to that without IKZF1 deletion. CK2 inhibitor treatment also results in an increase in IKZF1 binding to the RAG1 promoter and suppression of RAG1 expression in primary ALL cells. Taken together, these results demonstrate that RAG1 high expression is associated with high proliferation markers in B-ALL. Our data for the first time proved that RAG1 expression is directly suppressed by IKAROS. Our results also reveal drive oncogenesis of B-ALL is driven by high expression of RAG1 with IKAROS dysfunction together, which have significance in an integrated prognostic model for adult ALL.
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Affiliation(s)
- Qi Han
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Institute of Hematology Southeast University,Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Jinlong Ma
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Institute of Hematology Southeast University,Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Yan Gu
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Institute of Hematology Southeast University,Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Huihui Song
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Institute of Hematology Southeast University,Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Malika Kapadia
- Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA17033, USA
| | - Yuka Imamura Kawasawa
- International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,Genome Sciences and Bioinformatics Core Facility, Institute for Personalized Medicine, Penn State College of Medicine, Hershey, PA17033, USA
| | - Sinisa Dovat
- International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA17033, USA
| | - Chunhua Song
- International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA17033, USA
| | - Zheng Ge
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Institute of Hematology Southeast University,Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
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18
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Huang P, Wang F, Yang Y, Lai W, Meng M, Wu S, Peng H, Wang L, Zhan R, Imani S, Yu J, Chen B, Li X, Deng Y. Hematopoietic-Specific Deletion of Foxo1 Promotes NK Cell Specification and Proliferation. Front Immunol 2019; 10:1016. [PMID: 31139183 PMCID: PMC6519137 DOI: 10.3389/fimmu.2019.01016] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
We previously reported that deletion of Foxo1, via Ncr1-iCre mice from the expression of NKp46 onward, led to enhanced natural killer (NK) cell maturation and effector function. In this model, however, the role of Foxo1 in regulating NK cell specification and early development remains exclusive. Herein, we utilized a murine model of hematopoietic-specific deletion of Foxo1 before lymphoid specification, by crossing mice carrying floxed Foxo1 alleles (Foxo1fl/fl) with Vav1-iCre mice, to revisit the role of Foxo1 on NK cell specification and early development. The data showed that hematopoietic-specific deletion of Foxo1 resulted in increased proportion and numbers of common lymphoid progenitors (CLP) (Lin−CD127+c-Kit+Sca-1+), pre-pro NK b cells (Lin−Sca-1+c-Kit−CD135−CD127+), as well as committed Lin−CD122+ cells and CD3−CD19−NKp46+ NK cells in bone marrow. Hematopoietic-specific deletion of Foxo1 also promoted NK cells proliferation in a cell-intrinsic manner, indicated by increased Ki-67 expression and more expansion of NK cell after ex vivo stimulation with IL-15. The reason for Foxo1 suppressing NK cell proliferation might be its direct transcription of the cell-cycle inhibitory genes, such as p21cip1, p27kip1, p130, Gadd45a, and Ccng2 (cyclin G2) in NK cells, supported by the evidence of decreased mRNA expression of p21cip1, p27kip1, p130, Gadd45a, and Ccng2 in Foxo1-deficient NK cells and direct binding of Foxo1 on their promoter region. Furthermore, hematopoietic-specific deletion of Foxo1 resulted in increased ratio of mature NK subsets, such as CD11b+CD27− and CD43+KLRG1+ NK cells, but decreased ratio of immature NK subsets, such as CD27+CD11b− and CD27+CD11b+ NK cells, consistent with the findings in the murine model of Ncr1-iCre mediated Foxo1 deletion. Conclusively, Foxo1 not only acts as a negative checkpoint on NK cell maturation, but also represses NK cell specification and proliferation. The relative higher expression of Foxo1 in CLP and early NK precursors may also contribute to the later NK cell proliferation and responsiveness, which warranties another separate study in the future.
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Affiliation(s)
- Pei Huang
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Fangjie Wang
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yao Yang
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Wenjing Lai
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Meng Meng
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Shuting Wu
- Hunan Children's Hospital, Hunan Children's Research Institute (HCRI), University of South China, Changsha, China
| | - Hongyan Peng
- Hunan Children's Hospital, Hunan Children's Research Institute (HCRI), University of South China, Changsha, China
| | - Lili Wang
- Hunan Children's Hospital, Hunan Children's Research Institute (HCRI), University of South China, Changsha, China
| | - Rixing Zhan
- Southwest Hospital, Institute of Burn Research, Army Medical University (Third Military Medical University), Chongqing, China
| | - Saber Imani
- Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jianhua Yu
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Duarte, CA, United States
| | - Bingbo Chen
- Laboratory Animal Center, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiaohui Li
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
| | - Youcai Deng
- Institute of Materia Medica, College of Pharmacy, Army Medical University (Third Military Medical University), Chongqing, China
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19
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Kubagawa H, Honjo K, Ohkura N, Sakaguchi S, Radbruch A, Melchers F, Jani PK. Functional Roles of the IgM Fc Receptor in the Immune System. Front Immunol 2019; 10:945. [PMID: 31130948 PMCID: PMC6509151 DOI: 10.3389/fimmu.2019.00945] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/12/2019] [Indexed: 12/14/2022] Open
Abstract
It is now evident from studies of mice unable to secrete IgM that both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since identification of its Fc receptor (FcμR) by a functional cloning strategy in 2009, the roles of FcμR in these IgM effector functions have begun to be explored. Unlike Fc receptors for switched Ig isotypes (e.g., FcγRs, FcεRs, FcαR, Fcα/μR, pIgR, FcRn), FcμR is selectively expressed by lymphocytes: B, T, and NK cells in humans and only B cells in mice. FcμR may have dual signaling ability: one through a potential as yet unidentified adaptor protein non-covalently associating with the FcμR ligand-binding chain via a His in transmembrane segment and the other through its own Tyr and Ser residues in the cytoplasmic tail. FcμR binds pentameric and hexameric IgM with a high avidity of ~10 nM in solution, but more efficiently binds IgM when it is attached to a membrane component via its Fab region on the same cell surface (cis engagement). Four different laboratories have generated Fcmr-ablated mice and eight different groups of investigators have examined the resultant phenotypes. There have been some clear discrepancies reported that appear to be due to factors including differences in the exons of Fcmr that were targeted to generate the knockouts. One common feature among these different mutant mice, however, is their propensity to produce autoantibodies of both IgM and IgG isotypes. In this review, we briefly describe recent findings concerning the functions of FcμR in both mice and humans and propose a model for how FcμR plays a regulatory role in B cell tolerance.
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Affiliation(s)
| | - Kazuhito Honjo
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Naganari Ohkura
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Shimon Sakaguchi
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | | | | | - Peter K Jani
- Deutsches Rheuma-Forschungszentrum, Berlin, Germany
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20
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Shen M, Xu Z, Xu W, Jiang K, Zhang F, Ding Q, Xu Z, Chen Y. Inhibition of ATM reverses EMT and decreases metastatic potential of cisplatin-resistant lung cancer cells through JAK/STAT3/PD-L1 pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:149. [PMID: 30961670 PMCID: PMC6454747 DOI: 10.1186/s13046-019-1161-8] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/31/2019] [Indexed: 12/14/2022]
Abstract
Background The cisplatin-resistance is still a main course for chemotherapy failure of lung cancer patients. Cisplatin-resistant cancer cells own higher malignance and exhibited increased metastatic ability, but the mechanism is not clear. In this study, we investigated the effects of Ataxia Telangiectasia Mutated (ATM) on lung cancer metastasis. Materials and methods Cisplatin-resistant A549CisR and H157CisR cell line were generated by long-term treating parental A549 and H157 cells (A549P and H157P) with cisplatin. Cell growth, cell migration and cell invasion were determined. Gene expressions were determined by Western Blot and qPCR. Tumor metastasis was investigated using a xenograft mouse model. Results The IC50 of the cisplatin-resistant cells (A549CisR and H157CisR cells) to cisplatin was 6–8 higher than parental cells. The A549CisR and H157CisR cells expressed lower level of E-cadherin and higher levels of N-cadherin, Vimentin and Snail compared to the parental A549P and H157P cells, and exhibited stronger capabilities of metastatic potential compared to the parental cells. The ATM expression was upregulated in A549CisR and H157CisR cells and cisplatin treatment also upregulated expression of ATM in parental cells, The inhibition of ATM by using specific ATM inhibitor CP466722 or knock-down ATM by siRNA suppressed Epithelial-to-Mesenchymal transition (EMT) and metastatic potential of A549CisR and H157CisR cells. These data suggest that ATM mediates the cisplatin-resistance in lung cancer cells. Expressions of JAK1,2,、 STAT3 、PD-L1 and ATM were increased in A549CisR and H157CisR cells and could by induced by cisplatin in parental lung cancer cells. Interestedly, ATM upregulated PD-L1 expression via JAK1,2/STAT3 pathway and inhibition of ATM decreased JAK/STAT3 signaling and decreased PD-L1 expression. The treatment of PD-L1 neutralizing Ab reduced EMT and cell invasion. Inhibition of JAK1,2/STAT3 signaling by specific inhibitors suppressed ATM-induced PD-L1 expression, EMT and cell invasion. Importantly, inhibition of ATM suppressed EMT and tumor metastasis in cisplatin-resistant lung cancer cells in an orthotopic xenograft mouse model. Conclusions Our results show that ATM regulates PD-L1 expression through activation of JAK/STAT3 signaling in cisplatin-resistant cells. Overexpression of ATM contributes to cisplatin-resistance in lung cancer cells. Inhibition of ATM reversed EMT and inhibited cell invasion and tumor metastasis. Thus, ATM may be a potential target for the treatment of cisplatin-resistant lung cancer. Electronic supplementary material The online version of this article (10.1186/s13046-019-1161-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mingjing Shen
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Zhonghua Xu
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Weihua Xu
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Kanqiu Jiang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Fuquan Zhang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Qifeng Ding
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China
| | - Zhonghen Xu
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China.
| | - Yongbing Chen
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu, 215004, People's Republic of China.
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21
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Li J, Wang P, Gao J, Fei X, Liu Y, Ruan J. NaF Reduces KLK4 Gene Expression by Decreasing Foxo1 in LS8 Cells. Biol Trace Elem Res 2018; 186:498-504. [PMID: 29633120 DOI: 10.1007/s12011-018-1325-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
Decreased expression and increased phosphorylation of Forkhead box o1 (Foxo1) in ameloblasts were observed both in vivo and in vitro when treated by fluoride. The present study aims to investigate the possible relationship between Foxo1 and enamel matrix proteinases, matrix metalloproteinase 20 (MMP20), and kallikrein 4 (KLK4), in NaF-treated ameloblasts. Ameloblast-like cells (LS8 cells) were exposed to NaF at selected concentration (0/2 mM) for 24 h. Gene overexpression and silencing experiments were used to up- and down-regulate Foxo1 expression. The expression levels of Foxo1, MMP20, and KLK4 were detected by quantitative real-time PCR and western blot. Dual luciferase reporter assay was performed to evaluate the regulation of Foxo1 on the transcriptional activity of KLK4 promoter. The results showed that KLK4 expression was decreased in LS8 cells treated by NaF, while MMP20 expression was not changed. Foxo1 activation led to significantly up-regulation of KLK4 in LS8 cells under NaF condition. Knockout of Foxo1 markedly decreased klk4 expression in mRNA level, and intensified inhibition occurred in LS8 cells when combined with NaF treatment. However, the variation trend of MMP20 was not clear. Dual luciferase reporter assay showed that Foxo1 activation enhanced the transcriptional activity of KLK4 promoter. These findings suggest that the decrease of Foxo1 expression induced by high fluoride was a cause for low KLK4 expression.
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Affiliation(s)
- Juedan Li
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of General Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Peng Wang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Jianghong Gao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Xiuzhi Fei
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Yan Liu
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Jianping Ruan
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China.
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China.
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22
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Schabla NM, Perry GA, Palmer VL, Swanson PC. VprBP (DCAF1) Regulates RAG1 Expression Independently of Dicer by Mediating RAG1 Degradation. THE JOURNAL OF IMMUNOLOGY 2018; 201:930-939. [PMID: 29925675 DOI: 10.4049/jimmunol.1800054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/03/2018] [Indexed: 12/21/2022]
Abstract
The assembly of Ig genes in developing B lymphocytes by V(D)J recombination is initiated by the RAG1-RAG2 endonuclease complex. We previously identified an interaction between RAG1 and viral protein R binding protein (VprBP) (also known as DNA damage binding protein 1 cullin 4-associated factor 1 [DCAF1]), a substrate receptor for the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase (CRL4). We report in this article that in mice, B cell-intrinsic loss of VprBP increases RAG1 protein levels and disrupts expression of the endoribonuclease Dicer, which is essential for microRNA maturation. Rag1/2 transcription is known to be derepressed by loss of microRNA-mediated suppression of phosphatase and tensin homolog, raising the possibility that the elevated level of RAG1 observed in VprBP-deficient B cells is caused indirectly by the loss of Dicer. However, we show that VprBP restrains RAG1 expression posttranscriptionally and independently of Dicer. Specifically, loss of VprBP stabilizes RAG1 protein, which we show is normally degraded via a mechanism requiring both 20S proteasome and cullin-RING E3 ubiquitin ligase activity. Furthermore, we show that RAG1 stabilization through small molecule inhibition of cullin-RING E3 ubiquitin ligase activation promotes V(D)J recombination in a murine pre-B cell line. Thus, in addition to identifying a role for VprBP in maintaining Dicer levels in B cells, our findings reveal the basis for RAG1 turnover and provide evidence that the CRL4VprBP(DCAF1) complex functions to maintain physiological levels of V(D)J recombination.
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Affiliation(s)
- N Max Schabla
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Greg A Perry
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Victoria L Palmer
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
| | - Patrick C Swanson
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE 68178
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23
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Bahjat M, Guikema JEJ. The Complex Interplay between DNA Injury and Repair in Enzymatically Induced Mutagenesis and DNA Damage in B Lymphocytes. Int J Mol Sci 2017; 18:ijms18091876. [PMID: 28867784 PMCID: PMC5618525 DOI: 10.3390/ijms18091876] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/24/2017] [Accepted: 08/29/2017] [Indexed: 11/25/2022] Open
Abstract
Lymphocytes are endowed with unique and specialized enzymatic mutagenic properties that allow them to diversify their antigen receptors, which are crucial sensors for pathogens and mediators of adaptive immunity. During lymphocyte development, the antigen receptors expressed by B and T lymphocytes are assembled in an antigen-independent fashion by ordered variable gene segment recombinations (V(D)J recombination), which is a highly ordered and regulated process that requires the recombination activating gene products 1 & 2 (RAG1, RAG2). Upon activation by antigen, B lymphocytes undergo additional diversifications of their immunoglobulin B-cell receptors. Enzymatically induced somatic hypermutation (SHM) and immunoglobulin class switch recombination (CSR) improves the affinity for antigen and shape the effector function of the humoral immune response, respectively. The activation-induced cytidine deaminase (AID) enzyme is crucial for both SHM and CSR. These processes have evolved to both utilize as well as evade different DNA repair and DNA damage response pathways. The delicate balance between enzymatic mutagenesis and DNA repair is crucial for effective immune responses and the maintenance of genomic integrity. Not surprisingly, disturbances in this balance are at the basis of lymphoid malignancies by provoking the formation of oncogenic mutations and chromosomal aberrations. In this review, we discuss recent mechanistic insight into the regulation of RAG1/2 and AID expression and activity in lymphocytes and the complex interplay between these mutagenic enzymes and DNA repair and DNA damage response pathways, focusing on the base excision repair and mismatch repair pathways. We discuss how disturbances of this interplay induce genomic instability and contribute to oncogenesis.
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Affiliation(s)
- Mahnoush Bahjat
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
| | - Jeroen E J Guikema
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
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24
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Arya R, Bassing CH. V(D)J Recombination Exploits DNA Damage Responses to Promote Immunity. Trends Genet 2017; 33:479-489. [PMID: 28532625 PMCID: PMC5499712 DOI: 10.1016/j.tig.2017.04.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 11/16/2022]
Abstract
It has been recognized for 40 years that the variable (diversity) joining [V(D)J] recombination-mediated assembly of diverse B and T lymphocyte antigen receptor (AgR) genes is not only essential for adaptive immunity, but also a risk for autoimmunity and lymphoid malignancies. Over the past few years, several studies have revealed that recombination-activating gene (RAG) endonuclease-induced DNA double-strand breaks (DSBs) transcend hazardous intermediates during antigen receptor gene assembly. RAG cleavage within the genomes of lymphocyte progenitors and immature lymphocytes regulates the expression of ubiquitous and lymphocyte-specific gene transcripts to control the differentiation and function of both adaptive and innate immune cell lineages. These unexpected discoveries raise important new questions that have broad implications for basic immunology research and the screening, diagnosis, and treatment of human immunological disease.
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Affiliation(s)
- Rahul Arya
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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25
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Bahjat M, Bloedjes TA, van der Veen A, de Wilde G, Maas C, Guikema JEJ. Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay. J Vis Exp 2017. [PMID: 28654064 DOI: 10.3791/55703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The DNA damage response orchestrates the repair of DNA lesions that occur spontaneously, are caused by genotoxic stress, or appear in the context of programmed DNA breaks in lymphocytes. The Ataxia-Telangiectasia Mutated kinase (ATM), ATM- and Rad3-Related kinase (ATR) and the catalytic subunit of DNA-dependent Protein Kinase (DNA-PKcs) are among the first that are activated upon induction of DNA damage, and are central regulators of a network that controls DNA repair, apoptosis and cell survival. As part of a tumor-suppressive pathway, ATM and ATR activate p53 through phosphorylation, thereby regulating the transcriptional activity of p53. DNA damage also results in the formation of so-called ionizing radiation-induced foci (IRIF) that represent complexes of DNA damage sensor and repair proteins that accumulate at the sites of DNA damage, which are visualized by fluorescence microscopy. Co-localization of proteins in IRIFs, however, does not necessarily imply direct protein-protein interactions, as the resolution of fluorescence microscopy is limited. In situ Proximity Ligation Assay (PLA) is a novel technique that allows the direct visualization of protein-protein interactions in cells and tissues with unprecedented specificity and sensitivity. This technique is based on the spatial proximity of specific antibodies binding to the proteins of interest. When the interrogated proteins are within ~40 nm an amplification reaction is triggered by oligonucleotides that are conjugated to the antibodies, and the amplification product is visualized by fluorescent labeling, yielding a signal that corresponds to the subcellular location of the interacting proteins. Using the established functional interaction between ATM and p53 as an example, it is demonstrated here how PLA can be used in suspension cell cultures to study the direct interactions between proteins that are integral parts of the DNA damage response.
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Affiliation(s)
- Mahnoush Bahjat
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE)
| | - Timon A Bloedjes
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE)
| | - Amélie van der Veen
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE)
| | - Guus de Wilde
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE)
| | - Chiel Maas
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE)
| | - Jeroen E J Guikema
- Department of Pathology, Academic Medical Center, University of Amsterdam, Lymphoma and Myeloma Center Amsterdam (LYMMCARE);
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26
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Fisher MR, Rivera-Reyes A, Bloch NB, Schatz DG, Bassing CH. Immature Lymphocytes Inhibit Rag1 and Rag2 Transcription and V(D)J Recombination in Response to DNA Double-Strand Breaks. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 198:2943-2956. [PMID: 28213501 PMCID: PMC5360515 DOI: 10.4049/jimmunol.1601639] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/16/2017] [Indexed: 12/26/2022]
Abstract
Mammalian cells have evolved a common DNA damage response (DDR) that sustains cellular function, maintains genomic integrity, and suppresses malignant transformation. In pre-B cells, DNA double-strand breaks (DSBs) induced at Igκ loci by the Rag1/Rag2 (RAG) endonuclease engage this DDR to modulate transcription of genes that regulate lymphocyte-specific processes. We previously reported that RAG DSBs induced at one Igκ allele signal through the ataxia telangiectasia mutated (ATM) kinase to feedback-inhibit RAG expression and RAG cleavage of the other Igκ allele. In this article, we show that DSBs induced by ionizing radiation, etoposide, or bleomycin suppress Rag1 and Rag2 mRNA levels in primary pre-B cells, pro-B cells, and pro-T cells, indicating that inhibition of Rag1 and Rag2 expression is a prevalent DSB response among immature lymphocytes. DSBs induced in pre-B cells signal rapid transcriptional repression of Rag1 and Rag2, causing downregulation of both Rag1 and Rag2 mRNA, but only Rag1 protein. This transcriptional inhibition requires the ATM kinase and the NF-κB essential modulator protein, implicating a role for ATM-mediated activation of canonical NF-κB transcription factors. Finally, we demonstrate that DSBs induced in pre-B cells by etoposide or bleomycin inhibit recombination of Igκ loci and a chromosomally integrated substrate. Our data indicate that immature lymphocytes exploit a common DDR signaling pathway to limit DSBs at multiple genomic locations within developmental stages wherein monoallelic Ag receptor locus recombination is enforced. We discuss the implications of our findings for mechanisms that orchestrate the differentiation of monospecific lymphocytes while suppressing oncogenic Ag receptor locus translocations.
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Affiliation(s)
- Megan R Fisher
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Adrian Rivera-Reyes
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
| | - Noah B Bloch
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - David G Schatz
- Department of Immunobiology, Yale University School of Medicine, Howard Hughes Medical Institute, New Haven, CT 06520
| | - Craig H Bassing
- Division of Cancer Pathobiology, Department of Pathology and Laboratory Medicine, Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104;
- Immunology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Department of Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
- Cancer Biology Program of the Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104; and
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