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Luo H, Jiao QB, Shen CB, Gong WY, Yuan JH, Liu YY, Chen Z, Liu J, Xu XL, Cong YS, Zhang XW. UFMylation of HRD1 regulates endoplasmic reticulum homeostasis. FASEB J 2023; 37:e23221. [PMID: 37795761 DOI: 10.1096/fj.202300004rrrr] [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: 01/02/2023] [Revised: 08/28/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023]
Abstract
Ubiquitin fold modifier 1 is a small ubiquitin-like protein modifier that is essential for embryonic development of metazoans. Although UFMylation has been connected to endoplasmic reticulum homeostasis, the underlying mechanisms and the relevant cellular targets are largely unknown. Here, we show that HRD1, a ubiquitin ligase of ER-associated protein degradation (ERAD), is a novel substrate of UFM1 conjugation. HRD1 interacts with UFMylation components UFL1 and DDRGK1 and is UFMylated at Lys610 residue. In UFL1-depleted cells, the stability of HRD1 is increased and its ubiquitination modification is reduced. In the event of ER stress, the UFMylation and ubiquitination modification of HRD1 is gradually inhibited over time. Alteration of HRD1 Lys610 residue to arginine impairs its ability to degrade unfolded or misfolded proteins to disturb protein processing in ER. These results suggest that UFMylation of HRD1 facilitates ERAD function to maintain ER homeostasis.
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Affiliation(s)
- Hui Luo
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Qi-Bin Jiao
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Chuan-Bin Shen
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Wen-Yan Gong
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Jing-Hua Yuan
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Ying-Ying Liu
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Zhen Chen
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
| | - Jiang Liu
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xiao-Ling Xu
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yu-Sheng Cong
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xing-Wei Zhang
- School of Clinical Medicine, Affiliated Hospital of Hangzhou Normal University, Hangzhou Normal University, Hangzhou, China
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Bucheli OTM, Eyer K. Insights into the relationship between persistent antibody secretion and metabolic programming - A question for single-cell analysis. Immunol Lett 2023; 260:35-43. [PMID: 37315849 DOI: 10.1016/j.imlet.2023.06.006] [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: 11/02/2022] [Revised: 04/28/2023] [Accepted: 06/10/2023] [Indexed: 06/16/2023]
Abstract
Vaccination aims to generate a protective and persisting antibody response. Indeed, humoral vaccine-mediated protection depends on the quality and quantity of the produced antigen-specific antibodies for its initial magnitude and the persistence of the plasma cells for its duration. Therefore, understanding the mechanisms behind the generation, selection and maintenance of long-lived plasma cells secreting protective antibodies is of fundamental importance for understanding long-term immunity, vaccine responses, therapeutical approaches for autoimmune disease and multiple myeloma. Recent studies have observed correlations between the generation, function and lifespan of plasma cells and their metabolism, with metabolism being both a main driver and primary consequence of changes in cellular behavior. This review introduces how metabolic programs influence and drive immune cell functions in general and plasma cell differentiation and longevity more specifically, summarizing the current knowledge on metabolic pathways and their influences on cellular fate. In addition, available technologies to profile metabolism and their limitations are discussed, leading to the unique and open technological challenges for further advancement of this research field.
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Affiliation(s)
- Olivia T M Bucheli
- Laboratory for Functional Immune Repertoire Analysis, Institute of Pharmaceutical Sciences, D-CHAB, ETH Zürich, 8093 Zürich, Switzerland
| | - Klaus Eyer
- Laboratory for Functional Immune Repertoire Analysis, Institute of Pharmaceutical Sciences, D-CHAB, ETH Zürich, 8093 Zürich, Switzerland.
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3
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Tang TF, Chan YT, Cheong HC, Cheok YY, Anuar NA, Looi CY, Gan GG, Wong WF. Regulatory network of BLIMP1, IRF4, and XBP1 triad in plasmacytic differentiation and multiple myeloma pathogenesis. Cell Immunol 2022; 380:104594. [PMID: 36081178 DOI: 10.1016/j.cellimm.2022.104594] [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: 07/02/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 11/27/2022]
Abstract
Antibody secreting plasma cell plays an indispensable role in humoral immunity. As activated B cell undergoes germinal center reaction and develops into plasma cell, it gradually loses B cell characteristics and embraces functional changes associated with immunoglobulins production. Differentiation of B cell into plasma cell involves drastic changes in cell structure, granularity, metabolism, gene expression and epigenetic regulation that couple with the mounting capacity for synthesis of a large quantity of antigen-specific antibodies. The interplay between three hallmark transcriptional regulators IRF4, BLIMP1, and XBP1, is critical for supporting the cellular reprograming activities during B to plasma cell transition. IRF4 promotes plasma cell generation by directing immunoglobulin class switching, proliferation and survival; BLIMP1 serves as a transcriptional repressor that extinguishes B cell features; whereas XBP1 controls unfolded protein response that relieves endoplasmic reticulum stress and permits antibody release during terminal differentiation. Intriguingly, high expression of IRF4, BLIMP1, and XBP1 molecules have been reported in myeloma cells derived from multiple myeloma patients, which negatively impact treatment outcome, prognosis, and relapse frequency. Despite the introduction of immunomodulatory drugs in recent years, multiple myeloma is still an incurable disease with poor survival rate. An in-depth review of IRF4, BLIMP1, and XBP1 triad molecules in plasma cell generation and multiple myeloma tumorigenesis may provide clues to the possibility of targeting these molecules in disease management.
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Affiliation(s)
- Ting Fang Tang
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yee Teng Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Heng Choon Cheong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yi Ying Cheok
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Nur Adila Anuar
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chung Yeng Looi
- School of Bioscience, Taylor's University, 47500 Subang Jaya, Selangor, Malaysia
| | - Gin Gin Gan
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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4
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OBF1 and Oct factors control the germinal center transcriptional program. Blood 2021; 137:2920-2934. [PMID: 33512466 DOI: 10.1182/blood.2020010175] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
OBF1 is a specific coactivator of the POU family transcription factors OCT1 and OCT2. OBF1 and OCT2 are B cell-specific and indispensable for germinal center (GC) formation, but their mechanism of action is unclear. Here, we show by chromatin immunoprecipitation-sequencing that OBF1 extensively colocalizes with OCT1 and OCT2. We found that these factors also often colocalize with transcription factors of the ETS family. Furthermore, we showed that OBF1, OCT2, and OCT1 bind widely to the promoters or enhancers of genes involved in GC formation in mouse and human GC B cells. Short hairpin RNA knockdown experiments demonstrated that OCT1, OCT2, and OBF1 regulate each other and are essential for proliferation of GC-derived lymphoma cell lines. OBF1 downregulation disrupts the GC transcriptional program: genes involved in GC maintenance, such as BCL6, are downregulated, whereas genes related to exit from the GC program, such as IRF4, are upregulated. Ectopic expression of BCL6 does not restore the proliferation of GC-derived lymphoma cells depleted of OBF1 unless IRF4 is also depleted, indicating that OBF1 controls an essential regulatory node in GC differentiation.
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Yeremenko N, Danger R, Baeten D, Tomilin A, Brouard S. Transcriptional regulator BOB.1: Molecular mechanisms and emerging role in chronic inflammation and autoimmunity. Autoimmun Rev 2021; 20:102833. [PMID: 33864944 DOI: 10.1016/j.autrev.2021.102833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022]
Abstract
Lymphocytes constitute an essential and potent effector compartment of the immune system. Therefore, their development and functions must be strictly regulated to avoid inappropriate immune responses, such as autoimmune reactions. Several lines of evidence from genetics (e.g. association with multiple sclerosis and primary biliary cirrhosis), human expression studies (e.g. increased expression in target tissues and draining lymph nodes of patients with autoimmune diseases), animal models (e.g. loss of functional protein protects animals from the development of collagen-induced arthritis, experimental autoimmune encephalomyelitis, type 1 diabetes, bleomycin-induced fibrosis) strongly support a causal link between the aberrant expression of the lymphocyte-restricted transcriptional regulator BOB.1 and the development of autoimmune diseases. In this review, we summarize the current knowledge of unusual structural and functional plasticity of BOB.1, stringent regulation of its expression, and the pivotal role that BOB.1 plays in shaping B- and T-cell responses. We discuss recent developments highlighting the significant contribution of BOB.1 to the pathogenesis of autoimmune diseases and how to leverage our knowledge to target this regulator to treat autoimmune tissue inflammation.
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Affiliation(s)
- Nataliya Yeremenko
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France; Amsterdam Rheumatology and Immunology Center, Department of Clinical Immunology and Rheumatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands; Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.
| | - Richard Danger
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Dominique Baeten
- Amsterdam Rheumatology and Immunology Center, Department of Clinical Immunology and Rheumatology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands; Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Alexey Tomilin
- Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russian Federation
| | - Sophie Brouard
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
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6
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Inhibition of the IRE-1α/XBP-1 pathway prevents chronic GVHD and preserves the GVL effect in mice. Blood Adv 2019; 2:414-427. [PMID: 29483082 DOI: 10.1182/bloodadvances.2017009068] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 02/02/2018] [Indexed: 01/07/2023] Open
Abstract
Hematopoietic stem cell transplantation (HCT) is a curative procedure for hematological malignancies, but chronic graft-versus-host disease (cGVHD) remains a major complication after allogeneic HCT. Because donor B cells are essential for cGVHD development and B cells are sensitive to endoplasmic reticulum (ER) stress, we hypothesized that the IRE-1α/XBP-1 pathway is required for B-cell activation and function and for the development of cGVHD. To test this hypothesis, we used conditional knock-out mice deficient of XBP-1 specifically in B cells. Recipients transplanted with donor grafts containing XBP-1-deficient B cells displayed reduced cGVHD compared with controls. Reduction of cGVHD correlated with impaired B-cell functions, including reduced production of anti-double-stranded DNA immunoglobulin G antibodies, CD86, Fas, and GL7 surface expression, and impaired T-cell responses, including reduced interferon-γ production and follicular helper T cells. In a bronchiolitis obliterans cGVHD model, recipients of transplants containing XBP-1-deficient B cells demonstrated improved pulmonary function correlated with reduced donor splenic follicular helper T cells and increased B cells compared with those of wild-type control donor grafts. We then tested if XBP-1 blockade via an IRE-1α inhibitor, B-I09, would attenuate cGVHD and preserve the graft-versus-leukemia (GVL) effect. In a cutaneous cGVHD model, we found that prophylactic administration of B-I09 reduced clinical features of cGVHD, which correlated with reductions in donor T-cell and dendritic cell skin infiltrates. Inhibition of the IRE-1α/XBP-1 pathway also preserved the GVL effect against chronic myelogenous leukemia mediated by allogeneic splenocytes. Collectively, the ER stress response mediated by the IRE-1α/XBP-1 axis is required for cGVHD development but dispensable for GVL activity.
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7
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Song S, Matthias PD. The Transcriptional Regulation of Germinal Center Formation. Front Immunol 2018; 9:2026. [PMID: 30233601 PMCID: PMC6134015 DOI: 10.3389/fimmu.2018.02026] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/16/2018] [Indexed: 12/19/2022] Open
Abstract
Germinal centers (GCs) are essential structures of the humoral immune response, which form in the periphery in response to T cell dependent antigens. During the GC reaction, B cells undergo critical differentiation steps, which ultimately lead to the generation of antibodies with altered effector function and higher affinity for the selected antigen. Remarkably, many of the B cell tumors have their origin in the GCs; thus, understanding how the formation of these structures is regulated or deregulated is of high medical importance. This review gives an overview of the transcription factors that have been linked to the generation of GCs, and of their roles in the process.
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Affiliation(s)
- Shuang Song
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Faculty of Sciences, University of Basel, Basel, Switzerland
| | - Patrick D Matthias
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,Faculty of Sciences, University of Basel, Basel, Switzerland
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8
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Chen L, Li Q, She T, Li H, Yue Y, Gao S, Yan T, Liu S, Ma J, Wang Y. IRE1α-XBP1 signaling pathway, a potential therapeutic target in multiple myeloma. Leuk Res 2016; 49:7-12. [PMID: 27518808 DOI: 10.1016/j.leukres.2016.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 07/15/2016] [Accepted: 07/21/2016] [Indexed: 10/21/2022]
Abstract
Multiple myeloma (MM), which arises from the uncontrolled proliferation of malignant plasma cells, is the second most commonly diagnosed hematologic malignancy in the United States. Despite the development and application of novel drugs and autologous stem cell transplantation (ASCT), MM remains an incurable disease and patients become more prone to MM relapse and drug resistance. It is extremely urgent to find novel targeted therapy for MM. To date, the classic signaling pathways underlying MM have included the RAS/RAF/MEK/ERK pathway, the JAK-STAT3 pathway, the PI3K/Akt pathway and the NF-KB pathway. The IRE1α-XBP1 signaling pathway is currently emerging as an important pathway involved in the development of MM. Moreover, it is closely associated with the effect of MM treatment and its prognosis. All these findings indicate that the IRE1α-XBP1 pathway can be a potential treatment target. Herein, we investigate the relationship between the IRE1α-XBP1 pathway and MM and discuss the functions of IRE1α-XBP1-targeted drugs in the treatment of MM.
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Affiliation(s)
- Lin Chen
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Qian Li
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Tiantian She
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Han Li
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Yuanfang Yue
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Shuang Gao
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Tinghui Yan
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Su Liu
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Jing Ma
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China
| | - Yafei Wang
- Department of Hematology and Blood and Marrow Transplantation, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Huan-Hu-Xi Road, Ti-Yuan-Bei, He Xi District, Tianjin 300060, People's Republic of China.
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9
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Zhou H, Brekman A, Zuo WL, Ou X, Shaykhiev R, Agosto-Perez FJ, Wang R, Walters MS, Salit J, Strulovici-Barel Y, Staudt MR, Kaner RJ, Mezey JG, Crystal RG, Wang G. POU2AF1 Functions in the Human Airway Epithelium To Regulate Expression of Host Defense Genes. THE JOURNAL OF IMMUNOLOGY 2016; 196:3159-67. [PMID: 26927796 DOI: 10.4049/jimmunol.1502400] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/01/2016] [Indexed: 02/05/2023]
Abstract
In the process of seeking novel lung host defense regulators by analyzing genome-wide RNA sequence data from normal human airway epithelium, we detected expression of POU domain class 2-associating factor 1 (POU2AF1), a known transcription cofactor previously thought to be expressed only in lymphocytes. Lymphocyte contamination of human airway epithelial samples obtained by bronchoscopy and brushing was excluded by immunohistochemistry staining, the observation of upregulation of POU2AF1 in purified airway basal stem/progenitor cells undergoing differentiation, and analysis of differentiating single basal cell clones. Lentivirus-mediated upregulation of POU2AF1 in airway basal cells induced upregulation of host defense genes, including MX1, IFIT3, IFITM, and known POU2AF1 downstream genes HLA-DRA, ID2, ID3, IL6, and BCL6. Interestingly, expression of these genes paralleled changes of POU2AF1 expression during airway epithelium differentiation in vitro, suggesting POU2AF1 helps to maintain a host defense tone even in pathogen-free condition. Cigarette smoke, a known risk factor for airway infection, suppressed POU2AF1 expression both in vivo in humans and in vitro in human airway epithelial cultures, accompanied by deregulation of POU2AF1 downstream genes. Finally, enhancing POU2AF1 expression in human airway epithelium attenuated the suppression of host defense genes by smoking. Together, these findings suggest a novel function of POU2AF1 as a potential regulator of host defense genes in the human airway epithelium.
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Affiliation(s)
- Haixia Zhou
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Sichuan 610041, China; Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Angelika Brekman
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Wu-Lin Zuo
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Xuemei Ou
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Renat Shaykhiev
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | | | - Rui Wang
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Matthew S Walters
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Jacqueline Salit
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | | | - Michelle R Staudt
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
| | - Robert J Kaner
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, NY 10065; and
| | - Jason G Mezey
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, New York, NY 14853
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065; Division of Pulmonary and Critical Care Medicine, Department of Medicine, Weill Cornell Medical College, New York, NY 10065; and
| | - Guoqing Wang
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY 10065
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10
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Smith SM, Carew NT, Milcarek C. RNA polymerases in plasma cells trav-ELL2 the beat of a different drum. World J Immunol 2015; 5:99-112. [DOI: 10.5411/wji.v5.i3.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/19/2015] [Accepted: 11/17/2015] [Indexed: 02/05/2023] Open
Abstract
There is a major transformation in gene expression between mature B cells (including follicular, marginal zone, and germinal center cells) and antibody secreting cells (ASCs), i.e., ASCs, (including plasma blasts, splenic plasma cells, and long-lived bone marrow plasma cells). This significant change-over occurs to accommodate the massive amount of secretory-specific immunoglobulin that ASCs make and the export processes itself. It is well known that there is an up-regulation of a small number of ASC-specific transcription factors Prdm1 (B-lymphocyte-induced maturation protein 1), interferon regulatory factor 4, and Xbp1, and the reciprocal down-regulation of Pax5, Bcl6 and Bach2, which maintain the B cell program. Less well appreciated are the major alterations in transcription elongation and RNA processing occurring between B cells and ASCs. The three ELL family members ELL1, 2 and 3 have different protein sequences and potentially distinct cellular roles in transcription elongation. ELL1 is involved in DNA repair and small RNAs while ELL3 was previously described as either testis or stem-cell specific. After B cell stimulation to ASCs, ELL3 levels fall precipitously while ELL1 falls off slightly. ELL2 is induced at least 10-fold in ASCs relative to B cells. All of these changes cause the RNA Polymerase II in ASCs to acquire different properties, leading to differences in RNA processing and histone modifications.
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11
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Abstract
In eukaryotic cells, protein folding and modification in the endoplasmic reticulum (ER) is highly sensitive to disturbances of homeostasis. The accumulation of unfolded and misfolded proteins in the ER lumen, termed ER stress, activates intracellular signaling pathways to resolve the protein-folding defect. This unfolded protein response (UPR) increases the capacity of ER protein folding, reduces global protein synthesis, and activates ER-associated protein degradation. If ER stress is too severe or chronic, or the UPR is compromised and not able to restore ER protein-folding homeostasis, numerous apoptotic signaling pathways are activated. Preclinical and clinical studies in the past decade indicate that ER stress and the UPR have a significant impact on the pathogenesis of inflammatory bowel disease. Paneth and goblet cells, 2 epithelial cell populations in the gut, rely on a robust ER function for protein folding and secretion. Several immune cells are orchestrated by ER stress and the UPR for differentiation, activation, migration, and survival. In addition, a variety of exogenous and endogenous molecules in the intestinal lumen affect ER function, making ER stress and the UPR relevant cellular signals in intestinal homeostasis. Recent studies demonstrated that unresolved ER stress and/or dysregulated UPR may cause inflammatory bowel disease by inducing epithelial cell death, impairing mucosal barrier function, and activating proinflammatory response in the gut. With our increased understanding of ER stress in inflammatory bowel disease pathogenesis, it is now possible to develop novel therapies to improve ER protein-folding homeostasis and target-specific UPR pathways in cells residing in the intestinal mucosa.
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12
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Park KS, Bayles I, Szlachta-McGinn A, Paul J, Boiko J, Santos P, Liu J, Wang Z, Borghesi L, Milcarek C. Transcription elongation factor ELL2 drives Ig secretory-specific mRNA production and the unfolded protein response. THE JOURNAL OF IMMUNOLOGY 2014; 193:4663-74. [PMID: 25238757 DOI: 10.4049/jimmunol.1401608] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Differentiation of B cells into Ab-secreting cells induces changes in gene transcription, IgH RNA processing, the unfolded protein response (UPR), and cell architecture. The transcription elongation factor eleven nineteen lysine-rich leukemia gene (ELL2) stimulates the processing of the secreted form of the IgH mRNA from the H chain gene. Mice (mus musculus) with the ELL2 gene floxed in either exon 1 or exon 3 were constructed and crossed to CD19-driven cre/CD19(+). The B cell-specific ELL2 conditional knockouts (cKOs; ell2(loxp/loxp) CD19(cre/+)) exhibit curtailed humoral responses both in 4-hydroxy-3-nitrophenyl acetyl-Ficoll and in 4-hydroxy-3-nitrophenyl acetyl-keyhole limpet hemocyanin immunized animals; recall responses were also diminished. The number of immature and recirculating B cells in the bone marrow is increased in the cKOs, whereas plasma cells in spleen are reduced relative to control animals. There are fewer IgG1 Ab-producing cells in the bone marrow of cKOs. LPS ex vivo-stimulated B220(lo)CD138(+) cells from ELL2-deficient mouse spleens are 4-fold less abundant than from control splenic B cells; have a paucity of secreted IgH; and have distended, abnormal-appearing endoplasmic reticulum. IRE1α is efficiently phosphorylated, but the amounts of Ig κ, ATF6, BiP, Cyclin B2, OcaB (BOB1, Pou2af1), and XBP1 mRNAs, unspliced and spliced, are severely reduced in ELL2-deficient cells. ELL2 enhances the expression of BCMA (also known as Tnfrsf17), which is important for long-term survival. Transcription yields from the cyclin B2 and the canonical UPR promoter elements are upregulated by ELL2 cDNA. Thus, ELL2 is important for many aspects of Ab secretion, XBP1 expression, and the UPR.
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Affiliation(s)
- Kyung Soo Park
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Ian Bayles
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | | | - Joshua Paul
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Julie Boiko
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Patricia Santos
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - June Liu
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Zhou Wang
- Department of Urology, University of Pittsburgh Cancer Institute, Shadyside Medical Center, Pittsburgh, PA 15232
| | - Lisa Borghesi
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Christine Milcarek
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261; and
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13
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Zhou Y, Liu X, Xu L, Hunter ZR, Cao Y, Yang G, Carrasco R, Treon SP. Transcriptional repression of plasma cell differentiation is orchestrated by aberrant over-expression of the ETS factorSPIBin Waldenström macroglobulinaemia. Br J Haematol 2014; 166:677-89. [DOI: 10.1111/bjh.12936] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/31/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Yangsheng Zhou
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Xia Liu
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Lian Xu
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Zachary R. Hunter
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Yang Cao
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Guang Yang
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Ruben Carrasco
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
| | - Steven P. Treon
- Bing Center for Waldenström's Macroglobulinemia; Dana Farber Cancer Institute; Brigham and Women's Hospital; Boston MA USA
- Departments of Medicine and Pathology; Harvard Medical School; Boston MA USA
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14
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Corcoran L, Emslie D, Kratina T, Shi W, Hirsch S, Taubenheim N, Chevrier S. Oct2 and Obf1 as Facilitators of B:T Cell Collaboration during a Humoral Immune Response. Front Immunol 2014; 5:108. [PMID: 24688485 PMCID: PMC3960507 DOI: 10.3389/fimmu.2014.00108] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/03/2014] [Indexed: 11/16/2022] Open
Abstract
The Oct2 protein, encoded by the Pou2f2 gene, was originally predicted to act as a DNA binding transcriptional activator of immunoglobulin (Ig) in B lineage cells. This prediction flowed from the earlier observation that an 8-bp sequence, the “octamer motif,” was a highly conserved component of most Ig gene promoters and enhancers, and evidence from over-expression and reporter assays confirmed Oct2-mediated, octamer-dependent gene expression. Complexity was added to the story when Oct1, an independently encoded protein, ubiquitously expressed from the Pou2f1 gene, was characterized and found to bind to the octamer motif with almost identical specificity, and later, when the co-activator Obf1 (OCA-B, Bob.1), encoded by the Pou2af1 gene, was cloned. Obf1 joins Oct2 (and Oct1) on the DNA of a subset of octamer motifs to enhance their transactivation strength. While these proteins variously carried the mantle of determinants of Ig gene expression in B cells for many years, such a role has not been borne out for them by characterization of mice lacking functional copies of the genes, either as single or as compound mutants. Instead, we and others have shown that Oct2 and Obf1 are required for B cells to mature fully in vivo, for B cells to respond to the T cell cytokines IL5 and IL4, and for B cells to produce IL6 normally during a T cell dependent immune response. We show here that Oct2 affects Syk gene expression, thus influencing B cell receptor signaling, and that Oct2 loss blocks Slamf1 expression in vivo as a result of incomplete B cell maturation. Upon IL4 signaling, Stat6 up-regulates Obf1, indirectly via Xbp1, to enable plasma cell differentiation. Thus, Oct2 and Obf1 enable B cells to respond normally to antigen receptor signals, to express surface receptors that mediate physical interaction with T cells, or to produce and respond to cytokines that are critical drivers of B cell and T cell differentiation during a humoral immune response.
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Affiliation(s)
- Lynn Corcoran
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Dianne Emslie
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Tobias Kratina
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Wei Shi
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Susanne Hirsch
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Nadine Taubenheim
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
| | - Stephane Chevrier
- Molecular Immunology Division, Walter and Eliza Hall Institute of Medical Research , Melbourne, VIC , Australia ; Department of Medical Biology, The University of Melbourne , Melbourne, VIC , Australia
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15
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Wang JH, New JS, Xie S, Yang P, Wu Q, Li J, Luo B, Ding Y, Druey KM, Hsu HC, Mountz JD. Extension of the germinal center stage of B cell development promotes autoantibodies in BXD2 mice. ARTHRITIS AND RHEUMATISM 2013; 65:2703-12. [PMID: 23818250 PMCID: PMC3979745 DOI: 10.1002/art.38059] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Regulator of G protein signaling (RGS) proteins inhibit chemokine signaling by desensitizing G protein-coupled receptor signals. This study was undertaken to determine the mechanisms by which RGS13 promotes the generation of pathogenic autoantibodies in germinal centers (GCs), using BXD2-Rgs13-/- mice. METHODS Confocal and light microscopy imaging techniques were used to determine the location of cells that express RGS13 and activation-induced cytidine deaminase (AID) in the mouse spleen, and the number of plasmablasts. The levels of GC and plasma cell program transcripts in GC B cells were determined by real-time quantitative polymerase chain reaction (qPCR). Differential interleukin-17 (IL-17)-mediated expression of RGS13 in GC versus non-GC B cells was analyzed using A20 and 70Z/3 B cells. RESULTS In the spleens of BXD2 mice, RGS13 was mainly expressed by GC B cells and was stimulated by IL-17 but not IL-21. IL-17 up-regulated RGS13 in A20 GC cells but not 70Z/3 non-GC B cells. BXD2- Rgs13-/- mice exhibited smaller GCs and lower AID levels, suggesting lower somatic hypermutation and affinity maturation. However, GC B cells from BXD2- Rgs13-/- mice showed increased levels of IgMbright plasmablasts, up-regulation of the genes encoding plasma program, including interferon regulatory factor 4, B lymphocyte-induced maturation protein 1, and X-box binding protein 1 and the p-CREB target genes Fosb and Obf1, and down-regulation of the GC program genes Aid, Pax5, and Bach2 compared to BXD2 mice. BXD2-Rgs13-/- mice had lower titers of IgG autoantibodies and IgG deposits in the glomeruli, suggesting reduced autoantibody pathogenicity. CONCLUSION RGS13 deficiency is associated with a reduction in GC program genes and the exit of fewer pathogenic IgM plasmablasts in BXD2 mice. Our findings indicate that prolonged GC program, mediated by up-regulation of RGS13, enhances AID expression and enables the generation of pathogenic autoantibodies in autoreactive GCs.
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16
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Mueller K, Quandt J, Marienfeld RB, Weihrich P, Fiedler K, Claussnitzer M, Laumen H, Vaeth M, Berberich-Siebelt F, Serfling E, Wirth T, Brunner C. Octamer-dependent transcription in T cells is mediated by NFAT and NF-κB. Nucleic Acids Res 2013; 41:2138-54. [PMID: 23293002 PMCID: PMC3575799 DOI: 10.1093/nar/gks1349] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The transcriptional co-activator BOB.1/OBF.1 was originally identified in B cells and is constitutively expressed throughout B cell development. BOB.1/OBF.1 associates with the transcription factors Oct1 and Oct2, thereby enhancing octamer-dependent transcription. In contrast, in T cells, BOB.1/OBF.1 expression is inducible by treatment of cells with PMA/Ionomycin or by antigen receptor engagement, indicating a marked difference in the regulation of BOB.1/OBF.1 expression in B versus T cells. The molecular mechanisms underlying the differential expression of BOB.1/OBF.1 in T and B cells remain largely unknown. Therefore, the present study focuses on mechanisms controlling the transcriptional regulation of BOB.1/OBF.1 and Oct2 in T cells. We show that both calcineurin- and NF-κB-inhibitors efficiently attenuate the expression of BOB.1/OBF.1 and Oct2 in T cells. In silico analyses of the BOB.1/OBF.1 promoter revealed the presence of previously unappreciated combined NFAT/NF-κB sites. An array of genetic and biochemical analyses illustrates the involvement of the Ca2+/calmodulin-dependent phosphatase calcineurin as well as NFAT and NF-κB transcription factors in the transcriptional regulation of octamer-dependent transcription in T cells. Conclusively, impaired expression of BOB.1/OBF.1 and Oct2 and therefore a hampered octamer-dependent transcription may participate in T cell-mediated immunodeficiency caused by the deletion of NFAT or NF-κB transcription factors.
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Affiliation(s)
- Kerstin Mueller
- Institute of Physiological Chemistry, University Ulm, D-89081 Ulm, Germany, Institute of Pathology, University Ulm, D-89081 Ulm, Germany
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17
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Schönthal AH. Endoplasmic reticulum stress: its role in disease and novel prospects for therapy. SCIENTIFICA 2012; 2012:857516. [PMID: 24278747 PMCID: PMC3820435 DOI: 10.6064/2012/857516] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/12/2012] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle required for lipid biosynthesis, calcium storage, and protein folding and processing. A number of physiological and pathological conditions, as well as a variety of pharmacological agents, are able to disturb proper ER function and thereby cause ER stress, which severely impairs protein folding and therefore poses the risk of proteotoxicity. Specific triggers for ER stress include, for example, particular intracellular alterations (e.g., calcium or redox imbalances), certain microenvironmental conditions (e.g., hypoglycemia, hypoxia, and acidosis), high-fat and high-sugar diet, a variety of natural compounds (e.g., thapsigargin, tunicamycin, and geldanamycin), and several prescription drugs (e.g., bortezomib/Velcade, celecoxib/Celebrex, and nelfinavir/Viracept). The cell reacts to ER stress by initiating a defensive process, called the unfolded protein response (UPR), which is comprised of cellular mechanisms aimed at adaptation and safeguarding cellular survival or, in cases of excessively severe stress, at initiation of apoptosis and elimination of the faulty cell. In recent years, this dichotomic stress response system has been linked to several human diseases, and efforts are underway to develop approaches to exploit ER stress mechanisms for therapy. For example, obesity and type 2 diabetes have been linked to ER stress-induced failure of insulin-producing pancreatic beta cells, and current research efforts are aimed at developing drugs that ameliorate cellular stress and thereby protect beta cell function. Other studies seek to pharmacologically aggravate chronic ER stress in cancer cells in order to enhance apoptosis and achieve tumor cell death. In the following, these principles will be presented and discussed.
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Affiliation(s)
- Axel H. Schönthal
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, HMR-405, Los Angeles, CA 90033, USA
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18
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Ling SCW, Lau EKK, Al-Shabeeb A, Nikolic A, Catalano A, Iland H, Horvath N, Ho PJ, Harrison S, Fleming S, Joshua DE, Allen JD. Response of myeloma to the proteasome inhibitor bortezomib is correlated with the unfolded protein response regulator XBP-1. Haematologica 2011; 97:64-72. [PMID: 21993678 DOI: 10.3324/haematol.2011.043331] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Multiple myeloma, a malignancy of the antibody-secreting plasma cells, remains incurable by current therapy. However, the proteasome inhibitor bortezomib and other new drugs are revolutionizing its treatment. It remains unclear why myelomas are peculiarly sensitive to bortezomib, or what causes primary or acquired resistance. The 'unfolded protein response' is necessary for folding and assembly of immunoglobulin chains in both normal and malignant plasma cells, as well as for the disposal of incorrectly folded or unpaired chains via the ubiquitin-proteasome pathway. We tested the hypothesis that levels of transcription factor XBP-1, a major regulator of the unfolded protein response, predict response to bortezomib. DESIGN AND METHODS Expression of XBP-1 and other regulators of the unfolded protein response were measured in myeloma and other cancer cell lines and two cohorts of patients with refractory myeloma and correlated with sensitivity/response to bortezomib. Bortezomib-resistant myeloma cell lines were derived and the effects on expression of unfolded protein response regulators, immunoglobulin secretion, proteasome activity and cross-resistance to cytotoxic drugs and tunicamycin determined. The consequences of manipulation of XBP-1 levels for sensitivity to bortezomib were tested. RESULTS Low XBP-1 levels predicted poor response to bortezomib, both in vitro and in myeloma patients. Moreover, myeloma cell lines selected for resistance to bortezomib had down-regulated XBP-1 and immunoglobulin secretion. Expression of ATF6, another regulator of the unfolded protein response, also correlated with bortezomib sensitivity. Direct manipulation of XBP-1 levels had only modest effects on sensitivity to bortezomib, suggesting it is a surrogate marker of response to bortezomib rather than a target itself. CONCLUSIONS The unfolded protein response may be a relevant target pathway for proteasome inhibitors in the treatment of myeloma and its regulator XBP-1 is a potential response marker. (The BIR study was registered with Australian Clinical Trial Registry Number 12605000770662).
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Affiliation(s)
- Silvia C W Ling
- Haematology Consulting RooLiverpool Hospital, Locked Bag 7090, Liverpool BC NSW 1871, Australia
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19
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Ren X, Siegel R, Kim U, Roeder RG. Direct interactions of OCA-B and TFII-I regulate immunoglobulin heavy-chain gene transcription by facilitating enhancer-promoter communication. Mol Cell 2011; 42:342-55. [PMID: 21549311 DOI: 10.1016/j.molcel.2011.04.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 02/16/2011] [Accepted: 04/16/2011] [Indexed: 02/07/2023]
Abstract
B cell-specific coactivator OCA-B, together with Oct-1/2, binds to octamer sites in promoters and enhancers to activate transcription of immunoglobulin (Ig) genes, although the mechanisms underlying their roles in enhancer-promoter communication are unknown. Here, we demonstrate a direct interaction of OCA-B with transcription factor TFII-I, which binds to DICE elements in Igh promoters, that affects transcription at two levels. First, OCA-B relieves HDAC3-mediated Igh promoter repression by competing with HDAC3 for binding to promoter-bound TFII-I. Second, and most importantly, Igh 3' enhancer-bound OCA-B and promoter-bound TFII-I mediate promoter-enhancer interactions, in both cis and trans, that are important for Igh transcription. These and other results reveal an important function for OCA-B in Igh 3' enhancer function in vivo and strongly favor an enhancer mechanism involving looping and facilitated factor recruitment rather than a tracking mechanism.
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Affiliation(s)
- Xiaodi Ren
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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20
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Costa CZF, da Rosa SEA, de Camargo MM. The Unfolded Protein Response: How Protein Folding Became a Restrictive Aspect for Innate Immunity and B Lymphocytes1. Scand J Immunol 2011; 73:436-48. [DOI: 10.1111/j.1365-3083.2010.02504.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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21
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Pereira ER, Liao N, Neale GA, Hendershot LM. Transcriptional and post-transcriptional regulation of proangiogenic factors by the unfolded protein response. PLoS One 2010; 5. [PMID: 20824063 PMCID: PMC2932741 DOI: 10.1371/journal.pone.0012521] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 07/31/2010] [Indexed: 01/17/2023] Open
Abstract
Background Inadequate extracellular conditions can adversely affect the environment of the ER and impinge on the maturation of nascent proteins. The resultant accumulation of unfolded proteins activates a signal transduction pathway, known as the unfolded protein response, which serves primarily to protect the cell during stress and helps restore homeostasis to the ER. Principal Findings Microarray analysis of the unfolded protein response in a human medulloblastoma cell line treated with thapsigargin revealed that, in addition to known targets, a large number of proangiogenic factors were up-regulated. Real-Time PCR analyses confirmed that four of these factors, VEGFA, FGF2, angiogenin and IL8, were transcriptionally up-regulated in multiple cell lines by various ER stress inducers. Our studies on VEGFA regulation revealed that XBP-1(S), a UPR-inducible transcription factor, bound to two regions on the VEGFA promoter, and analysis of XBP-1 null mouse embryonic fibroblasts revealed that it contributes to VEGFA expression in response to ER stress. ATF4, another UPR-inducible transcription factor, also binds to the VEGFA gene, although its contribution to VEGFA transcription appeared to be fairly modest. We also found that VEGFA mRNA stability is increased in response to UPR activation, via activation of AMP kinase, demonstrating that increased mRNA levels occur at two regulatory points. In keeping with the mRNA levels, we found that VEGFA protein is secreted at levels as high as or higher than that achieved in response to hypoxia. Conclusions and Significance Our results indicate that the UPR plays a significant role in inducing positive regulators of angiogenesis. It also regulates VEGFA expression at transcriptional, post-transcriptional and post-translational levels and is likely to have widespread implications for promoting angiogenesis in response to normal physiological cues as well as in pathological conditions like cancer.
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Affiliation(s)
- Ethel R. Pereira
- Department of Genetics & Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Nan Liao
- Department of Genetics & Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Geoff A. Neale
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Linda M. Hendershot
- Department of Genetics & Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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22
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Ma Y, Shimizu Y, Mann MJ, Jin Y, Hendershot LM. Plasma cell differentiation initiates a limited ER stress response by specifically suppressing the PERK-dependent branch of the unfolded protein response. Cell Stress Chaperones 2010; 15:281-93. [PMID: 19898960 PMCID: PMC2866998 DOI: 10.1007/s12192-009-0142-9] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 08/21/2009] [Accepted: 08/24/2009] [Indexed: 02/07/2023] Open
Abstract
In response to terminal differentiation signals that enable B cells to produce vast quantities of antibodies, a dramatic expansion of the secretory pathway and a corresponding increase in the molecular chaperones and folding enzymes that aid and monitor immunoglobulin synthesis occurs. Recent studies reveal that the unfolded protein response (UPR), which is normally activated by endoplasmic reticulum (ER) stress, plays a critical role in this process. Although B cells activate all three branches of the UPR in response to pharmacological inducers of the pathway, plasma cell differentiation elicits only a partial UPR in which components of the PKR-like ER kinase (PERK) branch are not expressed. This prompted us to further characterize UPR activation during plasma cell differentiation. We found that in response to lipopolysaccharides (LPS)-induced differentiation of the I.29 micro(+) B cell line, Ire1 was activated early, which led to splicing of XBP-1. PERK was partially phosphorylated with similar kinetics, but this was not sufficient to activate its downstream target eIF-2alpha, which initiates translation arrest, or to induce other targets like CHOP or GADD34. Both of these events preceded increased Ig synthesis, arguing this is not the signal for activating these two transducers. Targets of activating transcription factor 6 (ATF6) were up-regulated considerably later, arguing that the ATF6 branch is activated by a distinct signal. Pretreatment with LPS inhibited activation of the PERK branch by pharmacological inducers of the UPR, suggesting that differentiation-induced signals specifically silence this branch. This unique ability to differentially regulate various branches of the UPR allows B cells to accomplish distinct outcomes via the same UPR machinery.
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Affiliation(s)
- Yanjun Ma
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
- Department of Medical Oncology, Sammons Cancer Center Baylor University Medical Center, Dallas, TX 75246 USA
| | - Yuichiro Shimizu
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
| | - Melissa J. Mann
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
| | - Yi Jin
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
- Department of Molecular Science, University of Tennessee Health Science Center, Memphis, TN 38163 USA
| | - Linda M. Hendershot
- Department of Genetics and Tumor Cell Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
- Department of Molecular Science, University of Tennessee Health Science Center, Memphis, TN 38163 USA
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23
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Masciarelli S, Fra AM, Pengo N, Bertolotti M, Cenci S, Fagioli C, Ron D, Hendershot LM, Sitia R. CHOP-independent apoptosis and pathway-selective induction of the UPR in developing plasma cells. Mol Immunol 2010; 47:1356-65. [PMID: 20044139 PMCID: PMC2830287 DOI: 10.1016/j.molimm.2009.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 11/26/2009] [Accepted: 12/06/2009] [Indexed: 01/28/2023]
Abstract
Upon antigen stimulation, B lymphocytes differentiate into antibody secreting cells (ASC), most of which undergo apoptosis after a few days of intense Ig production. Differentiation entails expansion of the endoplasmic reticulum (ER) and requires XBP1 but not other elements of the unfolded protein response, like PERK. Moreover, normal and malignant ASC are exquisitely sensitive to proteasome inhibitors, but the underlying mechanisms are poorly understood. Here we analyze the role of C/EBP homologous protein (CHOP), a transcription factor mediating apoptosis in many cell types that experience high levels of ER stress. CHOP is transiently induced early upon B cell stimulation: covalent IgM aggregates form more readily and IgM secretion is slower in chop(-/-) cells. Despite these subtle changes, ASC differentiation and lifespan are normal in chop(-/-) mice. Unlike fibroblasts and other cell types, chop(-/-) ASC are equally or slightly more sensitive to proteasome inhibitors and ER stressors, implying tissue-specific roles for CHOP in differentiation and stress.
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Affiliation(s)
- Silvia Masciarelli
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
| | - Anna M. Fra
- Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy
| | - Niccoló Pengo
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
- Universitá Vita-Salute, San Raffaele Scientific Institute, Milano, Italy
| | - Milena Bertolotti
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
| | - Simone Cenci
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
- Universitá Vita-Salute, San Raffaele Scientific Institute, Milano, Italy
| | - Claudio Fagioli
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
| | - David Ron
- Skirball Institute of Biomolecular Medicine and the Departments of Cell Biology, Medicine and Pharmacology, New York University School of Medicine, New York, NY, USA
| | | | - Roberto Sitia
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy
- Universitá Vita-Salute, San Raffaele Scientific Institute, Milano, Italy
- Institute Curie, Paris, France
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24
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Schmidlin H, Diehl SA, Blom B. New insights into the regulation of human B-cell differentiation. Trends Immunol 2009; 30:277-85. [PMID: 19447676 DOI: 10.1016/j.it.2009.03.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 03/25/2009] [Accepted: 03/26/2009] [Indexed: 10/20/2022]
Abstract
B lymphocytes provide the cellular basis of the humoral immune response. All stages of this process, from B-cell activation to formation of germinal centers and differentiation into memory B cells or plasma cells, are influenced by extrinsic signals and controlled by transcriptional regulation. Compared to naïve B cells, memory B cells display a distinct expression profile, which allows for their rapid secondary responses. Indisputably, many B-cell malignancies result from aberrations in the circuitry controlling B-cell function, particularly during the germinal centre (GC) reaction. Here, we review new insights into memory B-cell subtypes, recent literature on transcription factors regulating human B-cell differentiation and further evidence for B-cell lymphomagenesis emanating from errors during GC cell reactions.
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Affiliation(s)
- Heike Schmidlin
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, The Netherlands
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25
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Todd DJ, Lee AH, Glimcher LH. The endoplasmic reticulum stress response in immunity and autoimmunity. Nat Rev Immunol 2009; 8:663-74. [PMID: 18670423 DOI: 10.1038/nri2359] [Citation(s) in RCA: 459] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Many exogenous sources of stress can lead to cell death. In recent years, endogenous cellular sources of stress have also been identified, including the stress that arises from the accumulation of unfolded proteins within a cell's endoplasmic reticulum (ER). To counterbalance this type of ER stress, higher eukaryotic cells possess a three-pronged signal-transduction pathway termed the unfolded-protein response (UPR). This Review focuses on the role of the UPR in the mammalian immune system and how manipulation of this complex signalling pathway may be of therapeutic benefit in human disease.
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Affiliation(s)
- Derrich J Todd
- Department of Infectious Diseases and Immunology, Harvard School of Public Health, 651 Huntington Avenue, Boston, Massachusetts 02115, USA
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Dong M, Bridges JP, Apsley K, Xu Y, Weaver TE. ERdj4 and ERdj5 are required for endoplasmic reticulum-associated protein degradation of misfolded surfactant protein C. Mol Biol Cell 2008; 19:2620-30. [PMID: 18400946 DOI: 10.1091/mbc.e07-07-0674] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Mutations in the SFTPC gene associated with interstitial lung disease in human patients result in misfolding, endoplasmic reticulum (ER) retention, and degradation of the encoded surfactant protein C (SP-C) proprotein. In this study, genes specifically induced in response to transient expression of two disease-associated mutations were identified by microarray analyses. Immunoglobulin heavy chain binding protein (BiP) and two heat shock protein 40 family members, endoplasmic reticulum-localized DnaJ homologues ERdj4 and ERdj5, were significantly elevated and exhibited prolonged and specific association with the misfolded proprotein; in contrast, ERdj3 interacted with BiP, but it did not associate with either wild-type or mutant SP-C. Misfolded SP-C, ERdj4, and ERdj5 coprecipitated with p97/VCP indicating that the cochaperones remain associated with the misfolded proprotein until it is dislocated to the cytosol. Knockdown of ERdj4 and ERdj5 expression increased ER retention and inhibited degradation of misfolded SP-C, but it had little effect on the wild-type protein. Transient expression of ERdj4 and ERdj5 in X-box binding protein 1(-/-) mouse embryonic fibroblasts substantially restored rapid degradation of mutant SP-C proprotein, whereas transfection of HPD mutants failed to rescue SP-C endoplasmic reticulum-associated protein degradation. ERdj4 and ERdj5 promote turnover of misfolded SP-C and this activity is dependent on their ability to stimulate BiP ATPase activity.
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Affiliation(s)
- Mei Dong
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, and The University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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Poser I, Sarov M, Hutchins JRA, Hériché JK, Toyoda Y, Pozniakovsky A, Weigl D, Nitzsche A, Hegemann B, Bird AW, Pelletier L, Kittler R, Hua S, Naumann R, Augsburg M, Sykora MM, Hofemeister H, Zhang Y, Nasmyth K, White KP, Dietzel S, Mechtler K, Durbin R, Stewart AF, Peters JM, Buchholz F, Hyman AA. BAC TransgeneOmics: a high-throughput method for exploration of protein function in mammals. Nat Methods 2008; 5:409-15. [PMID: 18391959 DOI: 10.1038/nmeth.1199] [Citation(s) in RCA: 488] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 03/17/2008] [Indexed: 12/11/2022]
Abstract
The interpretation of genome sequences requires reliable and standardized methods to assess protein function at high throughput. Here we describe a fast and reliable pipeline to study protein function in mammalian cells based on protein tagging in bacterial artificial chromosomes (BACs). The large size of the BAC transgenes ensures the presence of most, if not all, regulatory elements and results in expression that closely matches that of the endogenous gene. We show that BAC transgenes can be rapidly and reliably generated using 96-well-format recombineering. After stable transfection of these transgenes into human tissue culture cells or mouse embryonic stem cells, the localization, protein-protein and/or protein-DNA interactions of the tagged protein are studied using generic, tag-based assays. The same high-throughput approach will be generally applicable to other model systems.
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Affiliation(s)
- Ina Poser
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany
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