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Lee G, Jang E, Youn J. CCAAT/enhancer binding protein β Induces Post-Switched B Cells to Produce Blimp1 and Differentiate into Plasma Cells. Immune Netw 2020; 20:e42. [PMID: 33163250 PMCID: PMC7609162 DOI: 10.4110/in.2020.20.e42] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/20/2020] [Accepted: 08/26/2020] [Indexed: 02/08/2023] Open
Abstract
Long-lasting post-switched plasma cells (PCs) arise mainly from germinal center (GC) reactions, but little is known about the mechanism by which GC B cells differentiate into PCs. Based on our observation that the expression of the transcription factor CCAAT/enhancer binding protein β (C/EPBβ) is associated with the emergence of post-switched PCs, we enquired whether a cell-autonomous function of C/EPBβ is involved in the program for PC development. To address this, we generated C/EPBβ-deficient mice in which the Cebpb locus was specifically deleted in B cells after transcription of the Ig γ1 constant gene segment (Cγ1). In response to in vitro stimulation, B cells from these Cebpbfl/flCγ1Cre/+ mice had defects in the induction of B lymphocyte-induced maturation protein 1 (Blimp1) and the formation of IgG1+ PCs, but not in proliferation and survival. At steady state, the Cebpbfl/flCγ1Cre/+ mice had reduced serum IgG1 titers but normal IgG2c and IgM titers. Moreover, upon immunization with T-dependent Ag, the mice produced reduced levels of Ag-specific IgG1 Ab, and were defective in the production of Ag-specific IgG1 Ab-secreting cells. These results suggest that a cell-autonomous function of C/EPBβ is crucial for differentiation of post-switched GC B cells into PCs through a Blimp1-dependent pathway.
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Affiliation(s)
- Geonhee Lee
- Laboratory of Autoimmunology, Department of Anatomy and Cell Biology, College of Medicine, Hanyang University, Seoul 04763, Korea
| | - Eunkyeong Jang
- Laboratory of Autoimmunology, Department of Anatomy and Cell Biology, College of Medicine, Hanyang University, Seoul 04763, Korea
| | - Jeehee Youn
- Laboratory of Autoimmunology, Department of Anatomy and Cell Biology, College of Medicine, Hanyang University, Seoul 04763, Korea
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2
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Yang W, Liu W, Wen C, Hu B, Jian S, Gang Y. A superoxide dismutase (MnSOD) with identification and functional characterization from the freshwater mussel Cristaria plicata. FISH & SHELLFISH IMMUNOLOGY 2019; 91:180-187. [PMID: 31078645 DOI: 10.1016/j.fsi.2019.04.307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/25/2019] [Accepted: 04/30/2019] [Indexed: 06/09/2023]
Abstract
Manganese superoxide dismutase (MnSOD) is a sort of important metalloenzyme that can catalyze ROS in the organisms. In this study, MnSOD cDNA of C. plicata, designated as CpMnSOD (accession no. MK465057), was cloned from hemocytes. The full-length cDNA of MnSOD was 1096 bp with a 672 bp open reading frame encoding 223 amino acids. The deduced amino acid sequence contained a mitochondrial-targeting sequence (MTS) of 18 amino acids in the N-terminus, and four conserved amino acids for manganese binding (H49, H97, D182, H186). CpMnSOD showed a high level (65-73%) of sequence similarity to MnSODs from other species. The results of Real-time quantitative PCR revealed that CpMnSOD mRNA constitutively expressed in tissues. The highest expression level was in hepatopancreas, followed by muscle, mantle and gill, and the lowest expression level was in hemocytes. After microcystin challenge, the expression levels of CpMnSOD mRNA were up-regulated in hemocytes and hepatopancreas. The cDNA of CpMnSOD was cloned into the plasmid pColdI-ZZ, and the recombinant protein was expressed in Escherichia coli BL21 (DE3). The enzyme stability assay showed that the purified CpMnSOD protein maintained more than 80% enzyme activity at temperature up to 70 °C, at pH 2.0-10.0, and resistant to 8 mol/L urea or 8% SDS.
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Affiliation(s)
- Wanying Yang
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China
| | - Wenxiu Liu
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China
| | - Chungen Wen
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China.
| | - Baoqing Hu
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China.
| | - Shaoqing Jian
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China
| | - Yang Gang
- College of Life Science, Education Ministry Key Laboratory of Poyang Lake Environment and Resource Utilization, Nanchang University, Nanchang, 330031, China
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3
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Li W, Tanikawa T, Kryczek I, Xia H, Li G, Wu K, Wei S, Zhao L, Vatan L, Wen B, Shu P, Sun D, Kleer C, Wicha M, Sabel M, Tao K, Wang G, Zou W. Aerobic Glycolysis Controls Myeloid-Derived Suppressor Cells and Tumor Immunity via a Specific CEBPB Isoform in Triple-Negative Breast Cancer. Cell Metab 2018; 28:87-103.e6. [PMID: 29805099 PMCID: PMC6238219 DOI: 10.1016/j.cmet.2018.04.022] [Citation(s) in RCA: 256] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 09/15/2017] [Accepted: 04/30/2018] [Indexed: 12/16/2022]
Abstract
Myeloid-derived suppressor cells (MDSCs) inhibit anti-tumor immunity. Aerobic glycolysis is a hallmark of cancer. However, the link between MDSCs and glycolysis is unknown in patients with triple-negative breast cancer (TNBC). Here, we detect abundant glycolytic activities in human TNBC. In two TNBC mouse models, 4T1 and Py8119, glycolysis restriction inhibits tumor granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) expression and reduces MDSCs. These are accompanied with enhanced T cell immunity, reduced tumor growth and metastasis, and prolonged mouse survival. Mechanistically, glycolysis restriction represses the expression of a specific CCAAT/enhancer-binding protein beta (CEBPB) isoform, liver-enriched activator protein (LAP), via the AMP-activated protein kinase (AMPK)-ULK1 and autophagy pathways, whereas LAP controls G-CSF and GM-CSF expression to support MDSC development. Glycolytic signatures that include lactate dehydrogenase A correlate with high MDSCs and low T cells, and are associated with poor human TNBC outcome. Collectively, tumor glycolysis orchestrates a molecular network of the AMPK-ULK1, autophagy, and CEBPB pathways to affect MDSCs and maintain tumor immunosuppression.
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Affiliation(s)
- Wei Li
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA; Department of Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1277, Wuhan, Hubei 430022, China
| | - Takashi Tanikawa
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Ilona Kryczek
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Houjun Xia
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Gaopeng Li
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Ke Wu
- Department of Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1277, Wuhan, Hubei 430022, China
| | - Shuang Wei
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Lili Zhao
- Department of Biostatistics, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Linda Vatan
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA
| | - Bo Wen
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, Ann Arbor, MI, USA
| | - Pan Shu
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, Ann Arbor, MI, USA
| | - Duxin Sun
- Department of Pharmaceutical Sciences, University of Michigan College of Pharmacy, Ann Arbor, MI, USA; University of Michigan Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Celina Kleer
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Max Wicha
- University of Michigan Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA; Department of Medicine, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Michael Sabel
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA; University of Michigan Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Kaixiong Tao
- Department of Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1277, Wuhan, Hubei 430022, China.
| | - Guobin Wang
- Department of Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue 1277, Wuhan, Hubei 430022, China.
| | - Weiping Zou
- Department of Surgery, University of Michigan School of Medicine, BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-0669, USA; University of Michigan Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA; Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA; Graduate Programs in Immunology and Tumor Biology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
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4
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Jing W, Zhong J, Ping LJ, Yan LH. Relationship between oxidative stress and inflammation in peripheral and cerebral system of oxonate-induced hyperuricemic rats. BRAZ J PHARM SCI 2018. [DOI: 10.1590/s2175-97902017000400229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Wu Jing
- Gansu Agricultural University, China; Pulmonary Hospital of Lanzhou, China
| | - Jia Zhong
- Gansu Agricultural University, China; Pulmonary Hospital of Lanzhou, China
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Gardiner JD, Abegglen LM, Huang X, Carter BE, Schackmann EA, Stucki M, Paxton CN, Lor Randall R, Amatruda JF, Putnam AR, Kovar H, Lessnick SL, Schiffman JD. C/EBPβ-1 promotes transformation and chemoresistance in Ewing sarcoma cells. Oncotarget 2018; 8:26013-26026. [PMID: 28148901 PMCID: PMC5432234 DOI: 10.18632/oncotarget.14847] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 01/16/2017] [Indexed: 12/26/2022] Open
Abstract
CEBPB copy number gain in Ewing sarcoma was previously shown to be associated with worse clinical outcome compared to tumors with normal CEBPB copy number, although the mechanism was not characterized. We employed gene knockdown and rescue assays to explore the consequences of altered CEBPB gene expression in Ewing sarcoma cell lines. Knockdown of EWS-FLI1 expression led to a decrease in expression of all three C/EBPβ isoforms while re-expression of EWS-FLI1 rescued C/EBPβ expression. Overexpression of C/EBPβ-1, the largest of the three C/EBPβ isoforms, led to a significant increase in colony formation when cells were grown in soft agar compared to empty vector transduced cells. In addition, depletion of C/EBPβ decreased colony formation, and re-expression of either C/EBPβ-1 or C/EBPβ-2 rescued the phenotype. We identified the cancer stem cell marker ALDH1A1 as a target of C/EBPβ in Ewing sarcoma. Furthermore, increased expression of C/EBPβ led to resistance to chemotherapeutic agents. In summary, we have identified CEBPB as an oncogene in Ewing sarcoma. Overexpression of C/EBPβ-1 increases transformation, upregulates expression of the cancer stem cell marker ALDH1A1, and leads to chemoresistance.
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Affiliation(s)
- Jamie D Gardiner
- Department of Pediatrics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Lisa M Abegglen
- Department of Pediatrics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Xiaomeng Huang
- Department of Pediatrics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Bryce E Carter
- School of Medicine, University of Utah, Salt Lake City, UT, USA
| | | | - Marcus Stucki
- Department of Pediatrics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Christian N Paxton
- ARUP Institute for Clinical and Experimental Pathology®, Salt Lake City, UT, USA
| | - R Lor Randall
- Department of Orthopaedic Surgery, Sarcoma Services, University of Utah, Salt Lake City, UT, USA
| | - James F Amatruda
- Department of Pediatrics, Internal Medicine and Molecular Biology, University of Texas Southwestern, Dallas, TX, USA
| | - Angelica R Putnam
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - Heinrich Kovar
- Children's Cancer Research Institute, St. Anna Kinderkrebsforschung, Vienna, Austria
| | - Stephen L Lessnick
- Center for Childhood Cancer and Blood Disorders, Nationwide Children's Hospital, and the Division of Pediatric Heme/Onc/BMT, The Ohio State University, Columbus, OH, USA
| | - Joshua D Schiffman
- Department of Pediatrics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
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Tamura I, Jozaki K, Sato S, Shirafuta Y, Shinagawa M, Maekawa R, Taketani T, Asada H, Tamura H, Sugino N. The distal upstream region of insulin-like growth factor-binding protein-1 enhances its expression in endometrial stromal cells during decidualization. J Biol Chem 2018; 293:5270-5280. [PMID: 29453285 DOI: 10.1074/jbc.ra117.000234] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/06/2018] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that decidualization of human endometrial stromal cells (ESCs) causes a genome-wide increase in the levels of acetylation of histone-H3 Lys-27 (H3K27ac). We also reported that the distal gene regions, more than 3 kb up- or downstream of gene transcription start sites have increased H3K27ac levels. Insulin-like growth factor-binding protein-1 (IGFBP-1) is a specific decidualization marker and has increased H3K27ac levels in its distal upstream region (-4701 to -7501 bp). Here, using a luciferase reporter gene construct containing this IGFBP-1 upstream region, we tested the hypothesis that it is an IGFBP-1 enhancer. To induce decidualization, we incubated ESCs with cAMP and found that cAMP increased luciferase expression, indicating that decidualization increased the transcriptional activity from the IGFBP-1 upstream region. Furthermore, CRISPR/Cas9-mediated deletion of this region in HepG2 cells significantly reduced IGFBP-1 expression, confirming its role as an IGFBP-1 enhancer. A ChIP assay revealed that cAMP increased the recruitment of the transcriptional regulators CCAAT enhancer-binding protein β (C/EBPβ), forkhead box O1 (FOXO1), and p300 to the IGFBP-1 enhancer in ESCs. Of note, C/EBPβ knockdown inhibited the stimulatory effects of cAMP on the levels of H3K27ac, chromatin opening, and p300 recruitment at the IGFBP-1 enhancer. These results indicate that the region -4701 to -7501 bp upstream of IGFBP-1 functions as an enhancer for IGFBP-1 expression in ESCs undergoing decidualization, that C/EBPβ and FOXO1 bind to the enhancer region to up-regulate IGFBP-1 expression, and that C/EBPβ induces H3K27ac by recruiting p300 to the IGFBP-1 enhancer.
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Affiliation(s)
- Isao Tamura
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Kosuke Jozaki
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Shun Sato
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Yuichiro Shirafuta
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Masahiro Shinagawa
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Ryo Maekawa
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Toshiaki Taketani
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Hiromi Asada
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Hiroshi Tamura
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Norihiro Sugino
- From the Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
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7
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Tamura I, Shirafuta Y, Jozaki K, Kajimura T, Shinagawa M, Maekawa R, Taketani T, Asada H, Sato S, Tamura H, Sugino N. Novel Function of a Transcription Factor WT1 in Regulating Decidualization in Human Endometrial Stromal Cells and Its Molecular Mechanism. Endocrinology 2017; 158:3696-3707. [PMID: 28977591 DOI: 10.1210/en.2017-00478] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/12/2017] [Indexed: 12/28/2022]
Abstract
The Wilms tumor suppressor gene (WT1) encodes an essential transcription factor regulating mammalian urogenital development. However, the function of WT1 in human endometrium is still unclear. The current study examined the involvement of WT1 in the regulation of IGF-binding protein-1 (IGFBP-1) and prolactin (PRL), which are specific markers of decidualization, in human endometrial stromal cells (ESCs) undergoing decidualization. ESCs isolated from proliferative-phase endometrium were incubated with cyclic adenosine monophosphate (cAMP) to induce decidualization. cAMP increased WT1 expression with the induction of IGFBP-1 and PRL. Knockdown of WT1 by small interfering RNA inhibited cAMP-induced expression of IGFBP-1 and PRL. cAMP also induced the recruitment of WT1 to the IGFBP-1 and PRL promoters. To investigate the mechanism by which WT1 is upregulated by cAMP, we focused on C/EBPβ, a gene that regulates the expression of many genes during decidualization. Knockdown of C/EBPβ decreased cAMP-increased WT1 expression. cAMP increased the recruitment of C/EBPβ to the WT1 enhancer that is located approximately 14,000 bp downstream from the transcription start site. To test the endogenous function of the WT1 enhancer region on WT1 expression, the endogenous WT1 enhancer region was deleted by CRISPR/Cas9 system in HEK293 cells. The increase of WT1 expression by cAMP was not observed in the enhancer-deleted clones. Chromatin immunoprecipitation assay revealed that this enhancer region has high levels of H3K27ac and H3K4me1, which are active enhancer marks. These results show the role of WT1 in regulating decidualization in human ESCs. C/EBPβ is an upstream gene that regulates WT1 expression by binding to the novel enhancer region.
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Affiliation(s)
- Isao Tamura
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Yuichiro Shirafuta
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Kousuke Jozaki
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Takuya Kajimura
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Masahiro Shinagawa
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Ryo Maekawa
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Toshiaki Taketani
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Hiromi Asada
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Shun Sato
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Hiroshi Tamura
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
| | - Norihiro Sugino
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Minamikogushi 1-1-1, Ube 755-8505, Japan
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Pulido-Salgado M, Vidal-Taboada JM, Saura J. C/EBPβ and C/EBPδ transcription factors: Basic biology and roles in the CNS. Prog Neurobiol 2015; 132:1-33. [PMID: 26143335 DOI: 10.1016/j.pneurobio.2015.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/08/2015] [Accepted: 06/16/2015] [Indexed: 02/01/2023]
Abstract
CCAAT/enhancer binding protein (C/EBP) β and C/EBPδ are transcription factors of the basic-leucine zipper class which share phylogenetic, structural and functional features. In this review we first describe in depth their basic molecular biology which includes fascinating aspects such as the regulated use of alternative initiation codons in the C/EBPβ mRNA. The physical interactions with multiple transcription factors which greatly opens the number of potentially regulated genes or the presence of at least five different types of post-translational modifications are also remarkable molecular mechanisms that modulate C/EBPβ and C/EBPδ function. In the second part, we review the present knowledge on the localization, expression changes and physiological roles of C/EBPβ and C/EBPδ in neurons, astrocytes and microglia. We conclude that C/EBPβ and C/EBPδ share two unique features related to their role in the CNS: whereas in neurons they participate in memory formation and synaptic plasticity, in glial cells they regulate the pro-inflammatory program. Because of their role in neuroinflammation, C/EBPβ and C/EBPδ in microglia are potential targets for treatment of neurodegenerative disorders. Any strategy to reduce C/EBPβ and C/EBPδ activity in neuroinflammation needs to take into account its potential side-effects in neurons. Therefore, cell-specific treatments will be required for the successful application of this strategy.
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Affiliation(s)
- Marta Pulido-Salgado
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Jose M Vidal-Taboada
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Josep Saura
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain.
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9
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Nerlich A, Ruangkiattikul N, Laarmann K, Janze N, Dittrich-Breiholz O, Kracht M, Goethe R. C/EBPβ is a transcriptional key regulator of IL-36α in murine macrophages. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:966-78. [PMID: 26066982 DOI: 10.1016/j.bbagrm.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/15/2015] [Accepted: 06/01/2015] [Indexed: 12/25/2022]
Abstract
Interleukin (IL)-36α - one of the novel members of the IL-1 family of cytokines - is a potent regulator of dendritic and T cells and plays an important role in inflammatory processes like experimental skin inflammation in mice and in mouse models for human psoriasis. Here, we demonstrate that C/EBPβ, a transcription factor required for the selective expression of inflammatory genes, is a key activator of the Il36A gene in murine macrophages. RNAi-mediated suppression of C/EBPβ expression in macrophages (C/EBPβ(low) cells) significantly impaired Il36A gene induction following challenge with LPS. Despite the presence of five predicted C/EBP binding sites, luciferase reporter assays demonstrated that C/EBPβ confers responsiveness to LPS primarily through a half-CRE•C/EBP element in the proximal Il36A promoter. Electrophoretic mobility shift assays showed that C/EBPβ but not CREB proteins interact with this critical half-CRE•C/EBP element. In addition, overexpression of C/EBPβ in C/EBPβ(low) cells enhanced the expression of Il36A whereas CREB-1 had no effect. Finally, chromatin immunoprecipitation confirmed that C/EBPβ but neither CREB-1, ATF-2 nor ATF4 is directly recruited to the proximal promoter region of the Il36A gene. Together, these findings demonstrate an essential role of C/EBPβ in the regulation of the Il36A gene via the proximal half-CRE•C/EBP element in response to inflammatory stimuli.
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Affiliation(s)
- Andreas Nerlich
- Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine, Foundation Hannover, 30173 Hannover, Germany.
| | - Nanthapon Ruangkiattikul
- Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine, Foundation Hannover, 30173 Hannover, Germany
| | - Kristin Laarmann
- Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine, Foundation Hannover, 30173 Hannover, Germany
| | - Nina Janze
- Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine, Foundation Hannover, 30173 Hannover, Germany
| | | | - Michael Kracht
- Rudolf -Buchheim-Institute of Pharmacology, Justus-Liebig-University Giessen, 35392 Giessen, Germany
| | - Ralph Goethe
- Institute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine, Foundation Hannover, 30173 Hannover, Germany
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10
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Becuwe P, Ennen M, Klotz R, Barbieux C, Grandemange S. Manganese superoxide dismutase in breast cancer: from molecular mechanisms of gene regulation to biological and clinical significance. Free Radic Biol Med 2014; 77:139-51. [PMID: 25224035 DOI: 10.1016/j.freeradbiomed.2014.08.026] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 01/06/2023]
Abstract
Breast cancer is one of the most common malignancies of all cancers in women worldwide. Many difficulties reside in the prediction of tumor metastatic progression because of the lack of sufficiently reliable predictive biological markers, and this is a permanent preoccupation for clinicians. Manganese superoxide dismutase (MnSOD) may represent a rational candidate as a predictive biomarker of breast tumor metastatic progression, because its gene expression is profoundly altered between early and advanced breast cancer, in contrast to expression in the normal mammary gland. In this review, we report the characterization of some gene polymorphisms and molecular mechanisms of SOD2 gene regulation, which allows a better understanding of how MnSOD is decreased in early breast cancer and increased in advanced breast cancer. Several studies display the biological significance of MnSOD level in proliferation as well as in invasive and angiogenic abilities of breast tumor cells by controlling superoxide anion radical (O2(•-)) and hydrogen peroxide (H2O2). Particularly, they report how these reactive oxygen species may activate some signaling pathways involved in breast tumor growth. Emerging understanding of these findings provides an interesting framework for guiding translational research and suggests a way to define precisely the clinical interest of MnSOD as a prognostic and/or predicting marker in breast cancer, by associating with some regulators involved in SOD2 gene regulation and other well-known biomarkers, in addition to the typical clinical parameters.
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Affiliation(s)
- Philippe Becuwe
- Centre de Recherche en Automatique de Nancy, UMR 7039 CNRS, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy Cedex, France.
| | - Marie Ennen
- Centre de Recherche en Automatique de Nancy, UMR 7039 CNRS, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - Rémi Klotz
- Centre de Recherche en Automatique de Nancy, UMR 7039 CNRS, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - Claire Barbieux
- Centre de Recherche en Automatique de Nancy, UMR 7039 CNRS, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - Stéphanie Grandemange
- Centre de Recherche en Automatique de Nancy, UMR 7039 CNRS, Faculté des Sciences et Technologies, Université de Lorraine, 54506 Vandoeuvre-lès-Nancy Cedex, France
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11
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Chokas AL, Bickford JS, Barilovits SJ, Rogers RJ, Qiu X, Newsom KJ, Beachy DE, Nick HS. A TEAD1/p65 complex regulates the eutherian-conserved MnSOD intronic enhancer, eRNA transcription and the innate immune response. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1205-16. [PMID: 24953189 DOI: 10.1016/j.bbagrm.2014.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/11/2014] [Accepted: 06/13/2014] [Indexed: 12/21/2022]
Abstract
Manganese superoxide dismutase (MnSOD), a critical anti-oxidant enzyme, detoxifies the mitochondrial-derived reactive oxygen species, superoxide, elicited through normal respiration or the inflammatory response. Proinflammatory stimuli induce MnSOD gene expression through a eutherian-conserved, intronic enhancer element. We identified two prototypic enhancer binding proteins, TEAD1 and p65, that when co-expressed induce MnSOD expression comparable to pro-inflammatory stimuli. TEAD1 causes the nuclear sequestration of p65 leading to a novel TEAD1/p65 complex that associates with the intronic enhancer and is necessary for cytokine induction of MnSOD. Unlike typical NF-κB-responsive genes, the induction of MnSOD does not involve p50. Beyond MnSOD, the TEAD1/p65 complex regulates a subset of genes controlling the innate immune response that were previously viewed as solely NF-κB-dependent. We also identified an enhancer-derived RNA (eRNA) that is induced by either proinflammatory stimuli or the TEAD1/p65 complex, potentially linking the intronic enhancer to intra- and interchromosomal gene regulation through the inducible eRNA.
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Affiliation(s)
- Ann L Chokas
- Departments of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Justin S Bickford
- Departments of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Sarah J Barilovits
- Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Richard J Rogers
- Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Anesthesiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Xiaolei Qiu
- Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Kimberly J Newsom
- Departments of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Dawn E Beachy
- Departments of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Harry S Nick
- Departments of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA; McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
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Kma L. Plant Extracts and Plant-Derived Compounds: Promising Players in Countermeasure Strategy Against Radiological Exposure: A Review. Asian Pac J Cancer Prev 2014; 15:2405-25. [DOI: 10.7314/apjcp.2014.15.6.2405] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Barilovits SJ, Newsom KJ, Bickford JS, Beachy DE, Rhoton-Vlasak A, Nick HS. Characterization of a mechanism to inhibit ovarian follicle activation. Fertil Steril 2014; 101:1450-7. [PMID: 24559722 DOI: 10.1016/j.fertnstert.2014.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/14/2014] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To demonstrate that a small molecule can induce the transcription factor Foxo3 in the ovary and lead to inhibition of follicle activation. DESIGN Cell culture, organ culture, and animal studies. SETTING University-based laboratory. ANIMAL(S) 23 female C57BL/6 mice. INTERVENTION(S) Human ovary cells and mouse ovaries in culture treated with 2-deoxyglucose (2-DG) to mimic glucose deprivation, and mice intraperitoneally injected with 100 mg/kg, 300 mg/kg, or 600 mg/kg 2-DG daily for 2 weeks. MAIN OUTCOME MEASURE(S) In cell and organ culture, Foxo3 expression analyzed by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR); in treated animals, expression of genes regulated by nutrient deprivation (Foxo3, ATF4, GRP78, CHOP, ASNS, c-Myc) measured in brain, kidney, and ovary by qRT-PCR; and ovarian follicles histologically classified and counted. RESULT(S) Foxo3 expression is induced by 2-DG at both the mRNA and protein level in human ovarian cell culture, possibly through ATF4-dependent gene regulation. Foxo3 expression is also induced by 2-DG in ovarian organ culture. Treatment of mice with 100 mg/kg 2-DG resulted in a 2.6 fold induction of Foxo3 in the ovary and a 58% decrease in type 3a primary follicles. CONCLUSION(S) Expression of Foxo3 is induced by nutrient deprivation in cell culture, organ culture, and in vivo. In mice, 2-DG treatment results in an inhibition of primordial follicle activation. These data indicate that Foxo3 induction by 2-DG may be useful for fertility preservation.
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Affiliation(s)
- Sarah J Barilovits
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida; Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida
| | - Kimberly J Newsom
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida
| | - Justin S Bickford
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida
| | - Dawn E Beachy
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida
| | - Alice Rhoton-Vlasak
- Department of Obstetrics and Gynecology, College of Medicine, University of Florida, Gainesville, Florida
| | - Harry S Nick
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida; Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida.
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14
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Tamura I, Sato S, Okada M, Tanabe M, Lee L, Maekawa R, Asada H, Yamagata Y, Tamura H, Sugino N. Importance of C/EBPβ binding and histone acetylation status in the promoter regions for induction of IGFBP-1, PRL, and Mn-SOD by cAMP in human endometrial stromal cells. Endocrinology 2014; 155:275-86. [PMID: 24248464 DOI: 10.1210/en.2013-1569] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dynamic changes of gene expressions occur in human endometrial stromal cells (ESCs) during decidualization. CCAAT/enhancer-binding proteinβ (C/EBPβ) regulates the expression of a number of decidualization-related genes. In addition to transcription factors, it is important to know the role of epigenetic mechanisms, such as histone modifications in the regulation of decidualization-related genes. This study investigated the molecular and epigenetic mechanisms by which cAMP up-regulates the expression of IGF-binding protein-1 (IGFBP-1), prolactin (PRL), and manganese superoxide dismutase (Mn-SOD) in ESC. ESCs isolated from proliferative phase endometrium were incubated with cAMP to induce decidualization. IGFBP-1, PRL, and Mn-SOD mRNA expressions were determined by real-time RT-PCR. The C/EBPβ binding and histone modification status (acetylation of histone-H3 lysine-27 [H3K27ac]) in the promoter were examined by chromatin immunoprecipitation assay. Knockdowns of C/EBPβ were performed using the small interfering RNA method. cAMP induced mRNA expressions of IGFBP-1 and PRL accompanied by the increases in both C/EBPβ binding activities and H3K27ac levels in the promoters. The stimulatory effects of cAMP on mRNA levels and H3K27ac levels were completely abolished by C/EBPβ knockdown. cAMP increased Mn-SOD mRNA levels and C/EBPβ binding activities in the enhancer region. C/EBPβ knockdown inhibited Mn-SOD mRNA levels. The H3K27ac levels in the enhancer were high before cAMP stimulus but were not further increased by cAMP and were not inhibited by C/EBPβ knockdown. These results show that C/EBPβ regulates the expression of IGFBP-1 and PRL by altering the histone acetylation status of their promoters but differently regulates Mn-SOD gene expression in human ESC during decidualization.
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Affiliation(s)
- Isao Tamura
- Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
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15
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Zhang D, Cui S, Guo H, Jiang S. Genomic structure, characterization and expression analysis of a manganese superoxide dismutase from pearl oyster Pinctada fucata. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 41:484-490. [PMID: 23880235 DOI: 10.1016/j.dci.2013.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/13/2013] [Accepted: 07/15/2013] [Indexed: 06/02/2023]
Abstract
Manganese superoxide dismutase (MnSOD) is a major component of the cellular defense mechanisms against oxidative damage. We cloned and analyzed the expression pattern and genomic structure of the MnSOD gene of pearl oyster Pinctada fucata, hereafter designated as PoMnSOD. The full-length PoMnSOD cDNA was 1080 bp in length and consisted of a 5'-untranslated region (UTR) of 222 bp, a 3'-UTR of 318 bp with a polyadenylation signal (AATAAA) at 15 nucleotides upstream of the poly (A) tail, and an open reading frame (ORF) of 540 bp encoding a polypeptide of 180 amino acids with an estimated molecular mass of 20.4 kDa and a predicted pI of 6.72. Sequence analysis showed that PoMnSOD contained MnSOD family signatures F(44)NGGGHLNH(52), I(97)QGSGWGWLA(106) and D(138)VWEHAYY(145), four conserved residues for manganese metal binding (H(4), H(52), D(138) and H(142)), and two potential N-glycosylation sites (N(33) and N(51)). Homology analysis revealed that PoMnSOD shared 47.6-55.9% identity and 57.4-65.6% similarity to the other known PoMnSOD amino acid sequences. PoMnSOD genomic DNA was 5040 bp in length and contained three exons and two introns, which was a tripartite organization and coincided with the consensus GT-AG splicing rule. PoMnSOD promoter contained the various transcription factors associated with the immune modulation and stress responses. Quantitative RT-PCR analysis demonstrated that PoMnSOD was constitutively expressed in all detected tissues, and PoMnSOD mRNA expression was significantly up-regulated in intestine, mantle, gills, digestive gland and haemocytes after Vibrio alginolyticus injection. These results suggested that PoMoSOD was an acute-response protein involved in the innate immune responses of pearl oyster, and provided general information about the mechanisms of innate immune defense against bacterial infection in pearl oyster.
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Affiliation(s)
- Dianchang Zhang
- Division of Aquaculture and Biotechnology, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China; Key Laboratory of South China Sea Fishery Resources Exploitation and Utilization, Ministry of Agriculture, Guangzhou 510300, China
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16
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Sookruksawong S, Pongsomboon S, Tassanakajon A. Genomic organization of the cytosolic manganese superoxide dismutase gene from the Pacific white shrimp, Litopenaeus vannamei, and its response to thermal stress. FISH & SHELLFISH IMMUNOLOGY 2013; 35:1395-1405. [PMID: 23994278 DOI: 10.1016/j.fsi.2013.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/28/2013] [Accepted: 08/07/2013] [Indexed: 06/02/2023]
Abstract
Cytosolic manganese superoxide dismutase (cMnSOD) is an important antioxidant enzyme which catalyzes the conversion of superoxides to oxygen and hydrogen peroxide in several organisms. In the Pacific white shrimp, Litopenaeus vannamei, three cMnSOD genes (LvcMnSOD1-3) have previously been characterized. Here, the genomic structure of LvcMnSOD2 and its mRNA expression in response to thermal stress was examined. Analysis of the nucleotide sequence demonstrated that LvcMnSOD2 is comprised of 2392 bp spanning from the ATG translation start site to the stop codon and contains six exons interrupted by five introns. The 5' region upstream of the LvcMnSOD2 gene contains several putative regulatory elements but lacks the accepted TATA sequence. The putative transcription factor binding elements that may be involved in LvcMnSOD2 mRNA expression level include activator protein-1 (AP-1), cAMP response element binding protein (CREB), upstream stimulatory factor (USF), CAAT-enhancer binding protein (C/EBP), nuclear factor-κB (NF-κB) and heat shock regulatory element (HSE). In addition, we compared the 5' upstream sequences of the LvcMnSOD2 gene between two shrimp strains that are resistant or susceptible to Taura syndrome virus (TSV), respectively, which revealed the absence of the USF and C/EBP elements at positions -2125 and -1986, respectively, in the TSV-susceptible shrimp line. Moreover, genomic variations between the two shrimp strains were detected in some of the putative C/EBP, USF, HSE and NF-κB transcription factor binding elements. That these genomic variations might be involved in the TSV resistance as well as in stress responses remains to be evaluated. The presence of 15 putative HSEs suggests that the expression of LvcMnSOD2 is regulated under thermal stress. Here, we found that in response to a 1 or 3 h thermal stress (35 °C), the mRNA expression levels of LvcMnSOD2 were significantly increased and then gradually decreased in the recovering phase at room temperature (25 °C) to control levels by 3 h after the heat shock. Thus, the antioxidant system may be induced to protect cells from the oxidative damage caused by thermal stress. The genomic organization of LvcMnSOD2 likely provides a clue to the mechanisms that might regulate the antioxidant defense pathway in shrimps and so potentially in marine invertebrates.
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Affiliation(s)
- Suchonma Sookruksawong
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand; Biotechnology Program, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand
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Balamurugan K, Sterneck E. The many faces of C/EBPδ and their relevance for inflammation and cancer. Int J Biol Sci 2013; 9:917-33. [PMID: 24155666 PMCID: PMC3805898 DOI: 10.7150/ijbs.7224] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 08/27/2013] [Indexed: 12/29/2022] Open
Abstract
The CCAAT/enhancer binding protein delta (CEBPD, C/EBPδ) is a transcription factor that modulates many biological processes including cell differentiation, motility, growth arrest, proliferation, and cell death. The diversity of C/EBPδ's functions depends in part on the cell type and cellular context and can have opposing outcomes. For example, C/EBPδ promotes inflammatory signaling, but it can also inhibit pro-inflammatory pathways, and in a mouse model of mammary tumorigenesis, C/EBPδ reduces tumor incidence but promotes tumor metastasis. This review highlights the multifaceted nature of C/EBPδ's functions, with an emphasis on pathways that are relevant for cancer and inflammation, and illustrates how C/EBPδ emerged from the shadow of its family members as a fascinating “jack of all trades.” Our current knowledge on C/EBPδ indicates that, rather than being essential for a specific cellular process, C/EBPδ helps to interpret a variety of cues in a cell-type and context-dependent manner, to adjust cellular functions to specific situations. Therefore, insights into the roles and mechanisms of C/EBPδ signaling can lead to a better understanding of how the integration of different signaling pathways dictates normal and pathological cell functions and physiology.
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Affiliation(s)
- Kuppusamy Balamurugan
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute, Frederick, MD-21702-1201, U.S.A
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18
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Bickford JS, Beachy DE, Newsom KJ, Barilovits SJ, Herlihy JDH, Qiu X, Walters JN, Li N, Nick HS. A distal enhancer controls cytokine-dependent human cPLA2α gene expression. J Lipid Res 2013; 54:1915-26. [PMID: 23549331 DOI: 10.1194/jlr.m037382] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Specific control of group IVA cytosolic phospholipase A2 (cPLA2α or PLA2G4A) expression modulates arachidonic acid production, thus tightly regulating the downstream effects of pro- and anti-inflammatory eicosanoids. The significance of this pathway in human disease is apparent in a range of pathologies from inflammation to tumorigenesis. While much of the regulation of cPLA2α has focused on posttranslational phosphorylation of the protein, studies on transcriptional regulation of this gene have focused only on proximal promoter regions. We have identified a DNase I hypersensitive site encompassing a 5' distal enhancer element containing a highly conserved consensus AP-1 site involved in transcriptional activation of cPLA2α by interleukin (IL)-1β. Chromatin immunoprecipitation (ChIP), knockdown, knockout, and overexpression analyses have shown that c-Jun acts both in a negative and positive regulatory role. Transcriptional activation of cPLA2α occurs through the phosphorylation of c-Jun in conjunction with increased association of C/EBPβ with the distal novel enhancer. The association of C/EBPβ with the transcriptional activation complex does not require an obvious DNA binding site. These data provide new and important contributions to the understanding of cPLA2α regulation at the transcriptional level, with implications for eicosanoid metabolism, cellular signaling, and disease pathogenesis.
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Affiliation(s)
- Justin S Bickford
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
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Decreased O-GlcNAcylation of the key proteins in kinase and redox signalling pathways is a novel mechanism of the beneficial effect of α-lipoic acid in diabetic liver. Br J Nutr 2013; 110:401-12. [PMID: 23312093 DOI: 10.1017/s0007114512005429] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The present study aimed to investigate the effects of the treatment with a-lipoic acid (LA), a naturally occurring compound possessing antioxidant activity, on liver oxidant stress in a rat model of streptozotocin (STZ)-induced diabetes by examining potential mechanistic points that influence changes in the expression of antioxidant enzymes such as catalase (CAT) and CuZn/Mn superoxide dismutase(s) (SOD). LA was administered for 4 weeks by daily intraperitoneal injections (10 mg/kg) to STZ-induced diabetic rats, starting from the last STZ treatment. LA administration practically normalised the activities of the indicators of hepatocellular injury, alanine and aspartate aminotransferases, and lowered oxidative stress, as observed by the thiobarbituric acid-reactive substance assay, restored the reduced glutathione:glutathione disulphide ratio and increased the protein sulfhydryl group content. The lower level of DNA damage detected by the comet assay revealed that LA reduced cytotoxic signalling, exerting a hepatoprotective effect. The LA-treated diabetic rats displayed restored specific enzymatic activities of CAT, CuZnSOD and MnSOD. Quantitative real-time PCR analysis showed that LA restored CAT gene expression to its physiological level and increased CuZnSOD gene expression, but the gene expression of MnSOD remained at the diabetic level. Although the amounts of CAT and CuZnSOD protein expression returned to the control levels, the protein expression of MnSOD was elevated. These results suggested that LA administration affected CAT and CuZnSOD expression mainly at the transcriptional level, and MnSOD expression at the post-transcriptional level. The observed LA-promoted decrease in the O-GlcNAcylation of extracellular signal-regulated kinase, protein 38 kinase, NF-kB, CCAAT/enhancer-binding protein and the antioxidative enzymes themselves in diabetic rats suggests that the regulatory mechanisms that supported the changes in antioxidative enzyme expression were also influenced by post-translational mechanisms.
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Umasuthan N, Revathy KS, Bathige SDNK, Lim BS, Park MA, Whang I, Lee J. A manganese superoxide dismutase with potent antioxidant activity identified from Oplegnathus fasciatus: genomic structure and transcriptional characterization. FISH & SHELLFISH IMMUNOLOGY 2013; 34:23-37. [PMID: 23022055 DOI: 10.1016/j.fsi.2012.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 09/06/2012] [Accepted: 09/06/2012] [Indexed: 06/01/2023]
Abstract
In this study, we describe the identification and characterization of manganese superoxide dismutase, an important antioxidant enzyme acting as the chief reactive oxygen species (ROS) scavenger, from rock bream Oplegnathus fasciatus (Of-mMnSOD) at genomic- and transcriptional-levels as well as the biological activity of recombinant protein. The Of-mMnSOD protein portrayed distinct MnSOD family features including signature motifs, metal association sites and the typical active site topology. It was also predicted to be localized in mitochondrial matrix. The Of-mMnSOD had a quinquepartite genome organization encompassing five exons interrupted by four introns. Comparison of its sequence and gene structure with that of other lineages emphasized its strong conservation among different vertebrates. The Of-mMnSOD was ubiquitously transcribed in different rock bream tissues with higher levels in blood cells and metabolically active tissues. Transcription of Of-mMnSOD was kinetically modulated in response to investigational challenges using mitogens (lipopolysaccharide and poly I:C) and live-pathogens (Edwardsiella tarda and rock bream irido virus) in blood cells and liver tissue. The purified recombinant Of-mMnSOD possessed potential antioxidant capacity and actively survived over a range of pH (7.5-11) and temperature (15-40 °C) conditions. Collectively, findings of this study suggest that Of-mMnSOD combats against oxidative stress and cellular damages induced by mitogen/pathogen-mediated inflammation, by detoxifying harmful ROS (O(2)(●-)) in rock bream.
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Affiliation(s)
- Navaneethaiyer Umasuthan
- Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea
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Dhar SK, St Clair DK. Manganese superoxide dismutase regulation and cancer. Free Radic Biol Med 2012; 52:2209-22. [PMID: 22561706 DOI: 10.1016/j.freeradbiomed.2012.03.009] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 03/06/2012] [Accepted: 03/06/2012] [Indexed: 01/03/2023]
Abstract
Mitochondria are the power plants of the eukaryotic cell and the integrators of many metabolic activities and signaling pathways important for the life and death of a cell. Normal aerobic cells use oxidative phosphorylation to generate ATP, which supplies energy for metabolism. To drive ATP production, electrons are passed along the electron transport chain, with some leaking as superoxide during the process. It is estimated that, during normal respiration, intramitochondrial superoxide concentrations can reach 10⁻¹² M. This extremely high level of endogenous superoxide production dictates that mitochondria are equipped with antioxidant systems that prevent consequential oxidative injury to mitochondria and maintain normal mitochondrial functions. The major antioxidant enzyme that scavenges superoxide anion radical in mitochondria is manganese superoxide dismutase (MnSOD). Extensive studies on MnSOD have demonstrated that MnSOD plays a critical role in the development and progression of cancer. Many human cancer cells harbor low levels of MnSOD proteins and enzymatic activity, whereas some cancer cells possess high levels of MnSOD expression and activity. This apparent variation in MnSOD level among cancer cells suggests that differential regulation of MnSOD exists in cancer cells and that this regulation may be linked to the type and stage of cancer development. This review summarizes current knowledge of the relationship between MnSOD levels and cancer with a focus on the mechanisms regulating MnSOD expression.
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Affiliation(s)
- Sanjit Kumar Dhar
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA
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Regulation of human microsomal prostaglandin E synthase-1 by IL-1β requires a distal enhancer element with a unique role for C/EBPβ. Biochem J 2012; 443:561-71. [DOI: 10.1042/bj20111801] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The studies of PGE2 (prostaglandin E2) biosynthesis have focused primarily on the role of cyclo-oxygenases. Efforts have shifted towards the specific PGE2 terminal synthases, particularly mPGES-1 (microsomal PGE synthase 1), which has emerged as the crucial inducible synthase with roles in pain, cancer and inflammation. mPGES-1 is induced by pro-inflammatory cytokines with studies focusing on the proximal promoter, mediated specifically through Egr-1 (early growth-response factor 1). Numerous studies demonstrate that the mPGES-1 promoter (PTGES) alone cannot account for the level of IL-1β (interleukin 1β) induction. We identified two DNase I-hypersensitive sites within the proximal promoter near the Egr-1 element and a novel distal site near −8.6 kb. Functional analysis of the distal site revealed two elements that co-operate with basal promoter expression and a stimulus-dependent enhancer. A specific binding site for C/EBPβ (CCAAT/enhancer-binding protein β) in the enhancer was directly responsible for inducible enhancer activity. ChIP (chromatin immunoprecipitation) analysis demonstrated constitutive Egr-1 binding to the promoter and induced RNA polymerase II and C/EBPβ binding to the promoter and enhancer respectively. Knockout/knockdown studies established a functional role for C/EBPβ in mPGES-1 gene regulation and the documented interaction between Egr-1 and C/EBPβ highlights the proximal promoter co-operation with a novel distal enhancer element in regulating inducible mPGES-1 expression.
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Induction of group IVC phospholipase A2 in allergic asthma: transcriptional regulation by TNFα in bronchoepithelial cells. Biochem J 2012; 442:127-37. [PMID: 22082005 DOI: 10.1042/bj20111269] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Airway inflammation in allergen-induced asthma is associated with eicosanoid release. These bioactive lipids exhibit anti- and pro-inflammatory activities with relevance to pulmonary pathophysiology. We hypothesized that sensitization/challenge using an extract from the ubiquitous fungus Aspergillus fumigatus in a mouse model of allergic asthma would result in altered phospholipase gene expression, thus modulating the downstream eicosanoid pathway. We observed the most significant induction in the group IVC PLA2 (phospholipase A2) [also known as cPLA2γ (cytosolic PLA2γ) or PLA2G4C]. Our results infer that A. fumigatus extract can induce cPLA2γ levels directly in eosinophils, whereas induction in lung epithelial cells is most likely to be a consequence of TNFα (tumour necrosis factor α) secretion by A. fumigatus-activated macrophages. The mechanism of TNFα-dependent induction of cPLA2γ gene expression was elucidated through a combination of promoter deletions, ChIP (chromatin immunoprecipitation) and overexpression studies in human bronchoepithelial cells, leading to the identification of functionally relevant CRE (cAMP-response element), NF-κB (nuclear factor κB) and E-box promoter elements. ChIP analysis demonstrated that RNA polymerase II, ATF-2 (activating transcription factor 2)-c-Jun, p65-p65 and USF (upstream stimulating factor) 1-USF2 complexes are recruited to the cPLA2γ enhancer/promoter in response to TNFα, with overexpression and dominant-negative studies implying a strong level of co-operation and interplay between these factors. Overall, our results link cytokine-mediated alterations in cPLA2γ gene expression with allergic asthma and outline a complex regulatory mechanism.
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Kim BM, Rhee JS, Park GS, Lee J, Lee YM, Lee JS. Cu/Zn- and Mn-superoxide dismutase (SOD) from the copepod Tigriopus japonicus: molecular cloning and expression in response to environmental pollutants. CHEMOSPHERE 2011; 84:1467-1475. [PMID: 21550634 DOI: 10.1016/j.chemosphere.2011.04.043] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 04/08/2011] [Accepted: 04/17/2011] [Indexed: 05/30/2023]
Abstract
Superoxide dismutase (SOD) is an important antioxidant enzyme which catalyzes conversion of superoxide to oxygen and hydrogen peroxide in aerobic organisms. Here, we cloned and sequenced the full-length cDNA and genomic DNA of two SODs from the copepod, Tigriopus japonicus: copper/zinc SOD (TJ-Cu/Zn-SOD) and manganese SOD (TJ-Mn-SOD). To define whether TJ-Mn-SOD is a cytosolic or a mitochondrial protein, a phylogenetic analysis was performed. The genomic structure of both TJ-SOD genes was determined with the promoter region sequences. In order to investigate their potential role in response to environmental pollutants, T. japonicus were treated with heavy metal (copper, zinc, and silver; 0, 10, 25, 50, and 100 μg L(-1)) and industrial chemicals (benzo[α]pyrene, 4-nonylphenol, and tributyltin; 0, 1, 5, 10, and 20 μg L(-1)) for 96 h. Subsequently, the TJ-Cu/Zn-SOD and TJ-Mn-SOD mRNA level was measured with quantitative real-time RT-PCR along with total SOD activity. The deduced amino acid residues of TJ-Cu/Zn-SOD and TJ-Mn-SOD possessed evolutionary conserved domains that are required for metal binding and Cu/ZnSOD-conserved signature sequences. The phylogenetic analysis revealed that TJ-Mn-SOD was closely clustered to mitochondrial Mn-SOD of another copepod, Lepeophtheirus salmonis. TJ-Cu/Zn-SOD gene had four exons and three introns, while the TJ-Mn-SOD gene consisted of two exons interrupted by one intron. In the 5'-flanking region of TJ-Cu/Zn-SOD and TJ-Mn-SOD, we observed several transcription regulatory elements such as p53, XRE, MRE, and ERE-half sites. In the response to heavy metals, Cu, Zn, and Ag, both TJ-Cu/Zn-SOD and TJ-Mn-SOD transcript levels along with enzyme levels were significantly increased at high concentrations (50 μg L(-1) and 100 μg L(-1)). Particularly, in the Cu- and Ag-exposed group, the expression of TJ-Mn-SOD mRNA was regulated more sensitively than the TJ-Cu/Zn-SOD mRNA level, indicating that the chemical susceptibility would be not correlated with the form of chemicals. B[a]P treatment showed a significant increase in the expression of both TJ-SODs mRNA level and enzyme level from 5 μg L(-1) concentration, while TBT decreased its expression at high concentrations (10 μg L(-1) and 20 μg L(-1)). 4-NP increased both TJ-SODs mRNA level at 1 μg L(-1) concentration, and then inhibited its expression from 5 μg L(-1) concentration to a lower level than the control. This finding suggests that TJ-Cu/Zn-SOD and TJ-Mn-SOD would be an inducible gene upon exposure to heavy metals and B[α]P, and could be used as a potential biomarker for the risk assessment of these environmental pollutants. This is the first report to elucidate response of SOD to environmental pollutants in copepods. Therefore, this study would give a clue to better understand the mode of action of antioxidant genes and enzymes under oxidative stress in marine invertebrates.
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Affiliation(s)
- Bo-Mi Kim
- Department of Chemistry, The Research Institute for Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea
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Marigo I, Bosio E, Solito S, Mesa C, Fernandez A, Dolcetti L, Ugel S, Sonda N, Bicciato S, Falisi E, Calabrese F, Basso G, Zanovello P, Cozzi E, Mandruzzato S, Bronte V. Tumor-induced tolerance and immune suppression depend on the C/EBPbeta transcription factor. Immunity 2010; 32:790-802. [PMID: 20605485 DOI: 10.1016/j.immuni.2010.05.010] [Citation(s) in RCA: 700] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/17/2010] [Accepted: 05/20/2010] [Indexed: 12/21/2022]
Abstract
Tumor growth is associated with a profound alteration in myelopoiesis, leading to recruitment of immunosuppressive cells known as myeloid-derived suppressor cells (MDSCs). We showed that among factors produced by various experimental tumors, the cytokines GM-CSF, G-CSF, and IL-6 allowed a rapid generation of MDSCs from precursors present in mouse and human bone marrow (BM). BM-MDSCs induced by GM-CSF+IL-6 possessed the highest tolerogenic activity, as revealed by the ability to impair the priming of CD8(+) T cells and allow long term acceptance of pancreatic islet allografts. Cytokines inducing MDSCs acted on a common molecular pathway and the immunoregulatory activity of both tumor-induced and BM-derived MDSCs was entirely dependent on the C/EBPbeta transcription factor. Adoptive transfer of tumor antigen-specific CD8(+) T lymphocytes resulted in therapy of established tumors only in mice lacking C/EBPbeta in the myeloid compartment, suggesting that C/EBPbeta is a critical regulator of the immunosuppressive environment created by growing cancers.
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Affiliation(s)
- Ilaria Marigo
- Department of Oncology and Surgical Sciences, University of Padua, 35128 Padua, Italy
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Cho YS, Lee SY, Bang IC, Kim DS, Nam YK. Genomic organization and mRNA expression of manganese superoxide dismutase (Mn-SOD) from Hemibarbus mylodon (Teleostei, Cypriniformes). FISH & SHELLFISH IMMUNOLOGY 2009; 27:571-576. [PMID: 19616630 DOI: 10.1016/j.fsi.2009.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 07/09/2009] [Accepted: 07/12/2009] [Indexed: 05/28/2023]
Abstract
The genomic structure of manganese superoxide dismutase (Mn-SOD) was characterized in Hemibarbus mylodon (Teleostei, Cypriniformes), an endangered freshwater fish species, and changes in Mn-SOD mRNA expression in response to various stimuli, such as challenge with lipopolysaccharide (LPS), bacteria, or heavy metals, were examined. H. mylodon Mn-SOD possesses well-conserved features of vertebrate Mn-SODs, including its homologous quinquepartite gene structure (five exons interrupted by four introns) and high sequence identity with vertebrate orthologs in coding regions, including a typical eukaryotic Mn-SOD signature. The 5'-regulatory upstream region of the H. mylodon Mn-SOD gene lacked a canonical TATA sequence; however, it displayed various transcription factor binding elements that may be involved in immune and stress responses, as well as the modulation of enzymes that mediate the metabolism of metals and other xenobiotics. Bioinformatic analysis of Mn-SOD genes from fish and mammalian genome databases revealed chromosomal synteny of the Mn-SOD locus in the vertebrate lineage. Mn-SOD transcripts were ubiquitously detected in diverse tissues with variable levels of basal expression using an RT-PCR assay. Mn-SOD expression in the liver and kidney were significantly modulated by injection of LPS (1, 5, or 10 microg g(-1) body weight), Edwardsiella tarda challenge (5 x 10(3) or 5 x 10(5) cells/fish), and heavy metal exposure (Cd, Cu, or Zn at 5 microM). Results from this study suggest that Mn-SOD plays an important role in the host defence against oxidative damage caused by infection-mediated inflammation and/or toxicant related stress in this species.
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Affiliation(s)
- Young Sun Cho
- Department of Aquaculture, Pukyong National University, Busan 608-737, South Korea
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Abstract
The idea of dominant mutations that interfere with the activity of a normal gene product has been known for more than 80 years-the famous Muller's antimorphs. However, only over half a century later, the mechanistic bases of dominant negative mutations (DNMs) were defined in a systematic way by Ira Herskowitz. Most analyses of DNMs consider only intralocus (interallelic) interactions. The typical textbook explanation invokes a defective subunit, which poisons a homo-dimer or a homo-oligomer. More complex cases exist and the quantitative dimension of this phenomenon will be explored here. The basic ideas underlying DN effects can be (and should be) extended to included epistatic (interloci) interactions. Indeed, poisoning heteromeric macromolecular complexes is per se a matter of 'transdominant' negative effects. In this context, non-allelic non-complementation is also considered. Given the importance of DNMs in human disease and in the study of gene function, understanding how they work is essential for understanding pathology and for the design of effective DN molecules that can also prove useful in therapeutics. Finally, the existence and potential relevance of an increasing number of physiological DN protein isoforms is briefly discussed.
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Affiliation(s)
- Reiner A Veitia
- Institut Jacques Monod, CNRS-UMR 7592, Bâtiment Buffon, 15 Rue Hélène Brion, Paris Cedex 13, France.
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Miao L, St. Clair DK. Regulation of superoxide dismutase genes: implications in disease. Free Radic Biol Med 2009; 47:344-56. [PMID: 19477268 PMCID: PMC2731574 DOI: 10.1016/j.freeradbiomed.2009.05.018] [Citation(s) in RCA: 557] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 05/10/2009] [Accepted: 05/15/2009] [Indexed: 01/22/2023]
Abstract
Numerous short-lived and highly reactive oxygen species (ROS) such as superoxide (O2(.-)), hydroxyl radical, and hydrogen peroxide are continuously generated in vivo. Depending upon concentration, location, and intracellular conditions, ROS can cause toxicity or act as signaling molecules. The cellular levels of ROS are controlled by antioxidant enzymes and small-molecule antioxidants. As major antioxidant enzymes, superoxide dismutases (SODs), including copper-zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase, and extracellular superoxide dismutase, play a crucial role in scavenging O2(.-). This review focuses on the regulation of the sod genes coding for these enzymes, with an emphasis on the human genes. Current knowledge about sod structure and regulation is summarized and depicted as diagrams. Studies to date on genes coding for Cu/ZnSOD (sod1) are mostly focused on alterations in the coding region and their associations with amyotrophic lateral sclerosis. Evaluation of nucleotide sequences reveals that regulatory elements of the sod2 gene reside in both the noncoding and the coding region. Changes associated with sod2 lead to alterations in expression levels as well as protein function. We also discuss the structural basis for the changes in SOD expression associated with pathological conditions and where more work is needed to establish the relationship between SODs and diseases.
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Affiliation(s)
| | - Daret K. St. Clair
- Author to whom correspondence should be addressed: Daret K. St.Clair, Ph.D., Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, HSRB 454, Lexington, KY 40536-0298, Phone: 1-(859) 257-3956, FAX: 1-(859) 323-1059,
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CCAAT/enhancer-binding protein beta: its role in breast cancer and associations with receptor tyrosine kinases. Expert Rev Mol Med 2009; 11:e12. [PMID: 19351437 DOI: 10.1017/s1462399409001033] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The CCAAT/enhancer-binding proteins (C/EBPs) are a family of leucine-zipper transcription factors that regulate gene expression to control cellular proliferation, differentiation, inflammation and metabolism. Encoded by an intronless gene, C/EBPbeta is expressed as several distinct protein isoforms (LAP1, LAP2, LIP) whose expression is regulated by the differential use of several in-frame translation start sites. LAP1 and LAP2 are transcriptional activators and are associated with differentiation, whereas LIP is frequently elevated in proliferative tissue and acts as a dominant-negative inhibitor of transcription. However, emerging evidence suggests that LIP can serve as a transcriptional activator in some cellular contexts, and that LAP1 and LAP2 might also have unique actions. The LIP:LAP ratio is crucial for the maintenance of normal growth and development, and increases in this ratio lead to aggressive forms of breast cancer. This review discusses the regulation of C/EBPbeta activity by post-translational modification, the individual actions of LAP1, LAP2 and LIP, and the functions and downstream targets that are unique to each isoform. The role of the C/EBPbeta isoforms in breast cancer is discussed and emphasis is placed on their interactions with receptor tyrosine kinases.
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