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Hu B, Liu T, Wu Z, Phan SH. P53 regulates CCAAT/Enhancer binding protein β gene expression. Gene 2023; 884:147675. [PMID: 37541559 DOI: 10.1016/j.gene.2023.147675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/13/2023] [Accepted: 07/28/2023] [Indexed: 08/06/2023]
Abstract
BACKGROUND The transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) is implicated in diverse processes and diseases. Its two isoforms, namely liver-enriched activator protein (LAP) and liver-enriched inhibitor protein (LIP) are translated from the same mRNA. They share the same C-terminal DNA binding domain except LAP has an extra N-terminal activation domain. Probably due to its higher affinity for its DNA cognate sequences, LIP can inhibit LAP transcriptional activity even at substoichiometric levels. However, the regulatory mechanism of C/EBPβ gene expression and the LAP: LIP ratio is unclear. METHODS In this study, the C/EBPβ promoter sequence was scanned for conserved P53 response element (P53RE), and binding of P53 to the C/EBPβ promoter was tested by Electrophoretic Mobility Shift Assay (EMSA) and chromatin immunoprecipitation assay. P53 over-expression and dominant negative P53 expression plasmids were transfected into rat lung fibroblasts and tested for C/EBPβ gene transcription and expression. Western blot analysis was used to test the regulation of C/EBPβ LAP and LIP isoforms. Constructs containing the LAP 5'untranslated region (5'UTR) or the LIP 5'UTR region were used to test the importance of 5'UTR in the control of C/EBPβ LAP and LIP translation. RESULTS The C/EBPβ promoter sequence was found to contain a conserved P53 response element (P53RE), which binds P53 as demonstrated by Electrophoresis Mobility Shift Assay and chromatin immunoprecipitation assays. P53 over-expression suppressed while dominant negative P53 stimulated C/EBPβ gene transcription and expression. Western blot analysis showed that P53 differentially regulated the translation of the C/EBPβ LAP and LIP isoforms through the regulation of eIF4E and eIF4E-BP1. Further studies with constructs containing the LAP 5'untranslated region (5'UTR) or the LIP 5'UTR region showed that the 5'UTR is important in differential control of C/EBPβ LAP and LIP translation. CONCLUSION Analysis of the effects of P53 on C/EBPβ expression revealed a novel mechanism by which P53 could antagonize the effects of C/EBPβ on its target gene expression. For the first time, P53 is shown to be a repressor of C/EBPβ gene expression at both transcriptional and translational levels, with a differential effect in the magnitude of the effect on LAP vs. LIP isoforms.
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Affiliation(s)
- Biao Hu
- Department of Internal Medicine, University of Michigan Medical School, 1600 Huron Parkway, Ann Arbor, MI 48109 USA
| | - Tianju Liu
- Department of Pathology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109 USA
| | - Zhe Wu
- Department of Pathology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109 USA
| | - Sem H Phan
- Department of Pathology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109 USA.
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Liu Y, Wang H, Zhang H, Wang J, Liu Q, Bi Y, Song S, Qiao X, Zhu K, Wu Y, Ji G. CUGBP1, a crucial factor for heart regeneration in mice. Cell Death Dis 2022; 13:120. [PMID: 35136022 PMCID: PMC8825809 DOI: 10.1038/s41419-022-04570-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 01/05/2022] [Accepted: 01/20/2022] [Indexed: 12/18/2022]
Abstract
The mammalian heart is capable of achieving perfect regeneration following cardiac injury through sustained cardiomyocyte proliferation during the early period after birth. However, this regenerative capacity is lost by postnatal day 7 and throughout adulthood. CUGBP1 is critical for normal cardiac development but its role in heart regeneration remains unclear. Cardiac CUGBP1 levels are high in the early postnatal period and soon downregulate to adult levels within 1 week following birth in mice. The simultaneously diminished regenerative capacity and CUGBP1 levels by postnatal day lead us to hypothesize that CUGBP1 may be beneficial in heart regeneration. In this study, the function of CUGBP1 in heart regeneration was tested by a heart apex resection mouse model. We demonstrate that cardiac inactivation of CUGBP1 impairs neonatal heart regeneration at P1, in turn, replenishment of CUGBP1 levels prolong regenerative potential at P8 and P14. Furthermore, our results imply that the Wnt/β-catenin signaling and GATA4 involve in the CUGBP1 modulated neonatal heart regeneration. Altogether, our findings support CUGBP1 as a key factor promoting post-injury heart regeneration and provide a potential therapeutic method for heart disease.
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Affiliation(s)
- Yang Liu
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Huiwen Wang
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
| | - Han Zhang
- Pediatric Cardiac Center, Beijing Anzhen Hospital, Capital Medical University, 100029, Beijing, China
| | - Jun Wang
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Qun Liu
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Youkun Bi
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Shaole Song
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Xinlong Qiao
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Keqi Zhu
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yanyun Wu
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Guangju Ji
- Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
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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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Vlasova-St Louis I, Dickson AM, Bohjanen PR, Wilusz CJ. CELFish ways to modulate mRNA decay. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:695-707. [PMID: 23328451 DOI: 10.1016/j.bbagrm.2013.01.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/03/2013] [Accepted: 01/05/2013] [Indexed: 12/14/2022]
Abstract
The CELF family of RNA-binding proteins regulates many steps of mRNA metabolism. Although their best characterized function is in pre-mRNA splice site choice, CELF family members are also powerful modulators of mRNA decay. In this review we focus on the different modes of regulation that CELF proteins employ to mediate mRNA decay by binding to GU-rich elements. After starting with an overview of the importance of CELF proteins during development and disease pathogenesis, we then review the mRNA networks and cellular pathways these proteins regulate and the mechanisms by which they influence mRNA decay. Finally, we discuss how CELF protein activity is modulated during development and in response to cellular signals. We conclude by highlighting the priorities for new experiments in this field. This article is part of a Special Issue entitled: RNA Decay mechanisms.
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Jones K, Timchenko L, Timchenko NA. The role of CUGBP1 in age-dependent changes of liver functions. Ageing Res Rev 2012; 11:442-9. [PMID: 22446383 DOI: 10.1016/j.arr.2012.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 12/14/2022]
Abstract
Aging liver is characterized by alterations of liver biology and by a reduction of many functions which are important for the maintenance of body homeostasis. The main dysfunctions include appearance of enlarged hepatocytes, impaired liver regeneration after partial hepatectomy (PH), development of hepatic steatosis, reduction of secretion of proteins and alterations in the hepatic sinusoid. RNA binding proteins are involved in the regulation of gene expression in all tissues including regulation of biological processes in the liver. This review is focused on the role of a conserved, multi-functional RNA-binding protein, CUGBP1, in the development of aging phenotype in the liver. CUGBP1 has been identified as a protein which binds to RNA CUG repeats expanded in Myotonic Dystrophy type 1 (DM1). CUGBP1 is highly expressed in the liver and regulates translation of proteins which are critical for maintenance of liver functions. In livers of young mice, CUGBP1 forms complexes with eukaryotic translation initiation factor eIF2 and supports translation of C/EBPβ and HDAC1 proteins, which are involved in liver growth, differentiation and liver cancer. Aging changes several signaling pathways which lead to the elevation of the CUGBP1-eIF2α complex and to an increase of translation of C/EBPβ and HDAC1. These proteins form multi-protein complexes with additional transcription factors and with chromatin remodeling proteins causing epigenetic alterations of gene expression in livers of old mice. It appears that CUGBP1-mediated translational elevation of HDAC1 is one of the key events in the epigenetic changes in livers of old mice, leading to the development of age-associated dysfunctions of the liver. This review will also discuss a possible role of CUGBP1 in liver dysfunction in patients affected with DM1.
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6
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Smink JJ, Leutz A. Instruction of mesenchymal cell fate by the transcription factor C/EBPβ. Gene 2012; 497:10-7. [PMID: 22306325 DOI: 10.1016/j.gene.2012.01.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/13/2011] [Accepted: 01/19/2012] [Indexed: 01/10/2023]
Abstract
The transcription factor CCAAT/enhancer binding protein beta (C/EBPβ) plays a role in the differentiation of a large variety of cell types. C/EBPβ was initially described as an early inducer of adipocyte differentiation, however, recent data have shown that this is not the only mesenchymal cell lineage where C/EBPβ has an instructive function. Mouse models and tissue culture studies have now established a regulatory role of C/EBPβ in osteoblast and in chondrocyte differentiation. These three different cell lineages are derived from the same precursor, the mesenchymal stem cell (MSC). This review will focus on the emerging role of C/EBPβ and its different protein isoforms in various mesenchymal cell lineages and its function in adipocyte, chondrocyte and osteoblast differentiation. Moreover, the mesenchymal stem cell has attracted the attention of regenerative medicine in recent years, and the possible role of C/EBPβ in this respect will be discussed.
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Affiliation(s)
- Jeske J Smink
- Max Delbrueck Center for Molecular Medicine, Berlin-Brandenburg Center for Regenerative Therapies, Berlin, Germany
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Involvement of pregnane X receptor in the regulation of CYP2B6 gene expression by oltipraz in human hepatocytes. Toxicol In Vitro 2010; 24:452-9. [DOI: 10.1016/j.tiv.2009.09.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 09/25/2009] [Accepted: 09/28/2009] [Indexed: 11/24/2022]
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8
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Yamada T, Kawakami SI, Nakanishi N. Effects of dietary roughage levels on the expression of adipogenic transcription factors in Wagyu steers. Meat Sci 2009; 83:775-81. [DOI: 10.1016/j.meatsci.2009.08.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 05/01/2009] [Accepted: 08/10/2009] [Indexed: 10/20/2022]
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9
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Yang YM, Kim HE, Ki SH, Kim SG. Metadoxine, an ion-pair of pyridoxine and L-2-pyrrolidone-5-carboxylate, blocks adipocyte differentiation in association with inhibition of the PKA-CREB pathway. Arch Biochem Biophys 2009; 488:91-9. [PMID: 19607801 DOI: 10.1016/j.abb.2009.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/30/2009] [Accepted: 07/09/2009] [Indexed: 11/19/2022]
Abstract
Adipogenesis is orchestrated by the expression of master adipogenic regulators. In particular, phosphorylation of cAMP response element binding protein (CREB) by protein kinase A promotes CREB nuclear translocation, thereby inducing expression of the adipogenic regulators and resulting in adipogenic maturation. Although metadoxine, an ion-pair of pyridoxine and l-2-pyrrolidone-5-carboxylate, has been shown to inhibit lipid accumulation in the liver, its effect on adipocyte differentiation has never been explored. This study investigated the effects of metadoxine on the differentiation of 3T3-L1 preadipocytes and the molecular mechanism. Metadoxine treatment did not inhibit mitotic clonal expansion, but inhibited late-stage cell differentiation, suggesting that metadoxine may block the differentiation step of preadipocytes. Metadoxine inhibited CREB phosphorylation and binding to the cAMP response element, thereby repressing CCAAT/enhancer-binding protein beta during hormone-induced adipogenesis. Overall, metadoxine inhibits adipogenic differentiation in association with the inhibition of CREB/cAMP response element-dependent CCAAT/enhancer-binding protein beta induction in the protein kinase A-CREB pathway.
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Affiliation(s)
- Yoon Mee Yang
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Sillim-dong, Kwanak-gu, Seoul 151-742, South Korea
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10
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Brooks SC, Brooks JS, Lee WH, Lee MG, Kim SG. Therapeutic potential of dithiolethiones for hepatic diseases. Pharmacol Ther 2009; 124:31-43. [PMID: 19563826 DOI: 10.1016/j.pharmthera.2009.06.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2009] [Indexed: 01/09/2023]
Abstract
Comprehensive studies support the notion that oltipraz [4-methyl-5-(2-pyrazynyl)-1,2-dithiole-3-thione] and its congeners exert cancer chemopreventive effects by the prevention, inhibition or reversal of carcinogenic processes. Recently, it was found that dithiolethione compounds had the activities to prevent or treat fibrosis, insulin resistance, and mitochondrial protective effects in the liver by a mechanism involving AMP-activated protein kinase (AMPK) and/or 70-kDa ribosomal protein S6 kinase 1 (S6K1). Moreover, chemical regulation of the AMPK-S6K1 pathway was found to affect Liver X receptor (LXR) activity and lipogenesis, leading to the identification of AMPK and S6K1 as targets for treating hepatic steatosis. These biological activities of dithiolethiones may offer a novel approach to pharmaceutical intervention. This review focuses on the interaction between oltipraz and the AMPK-mTOR-S6K1 pathway, which regulates genes that confer hepatocyte protection from intoxication, disrupted energy metabolism, and inflammation. In terms of therapeutic potential, the findings reviewed here demonstrate a new therapeutic potential for dithiolethiones, which function in a unique manner, and offer the possibility of new treatments for hepatic diseases.
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Affiliation(s)
- Samuel Carroll Brooks
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, South, Korea
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11
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Kang KW. This month in APR. Arch Pharm Res 2009; 32:463-4. [PMID: 19407961 DOI: 10.1007/s12272-009-0002-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Cho IJ, Sung DK, Kang KW, Kim SG. Oltipraz promotion of liver regeneration after partial hepatectomy: The role of PI3-kinase-dependent C/EBPbeta and cyclin E regulation. Arch Pharm Res 2009; 32:625-35. [PMID: 19407981 DOI: 10.1007/s12272-009-1419-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 03/31/2009] [Accepted: 03/31/2009] [Indexed: 12/17/2022]
Abstract
Oltipraz, a representative cancer chemopreventive agent, regenerates cirrhotic liver via CCAAT/enhancer binding protein beta (C/EBPbeta). This study examined the effect of oltipraz on liver regeneration after partial hepatectomy (PH) and explored the role of phosphatidylinositol 3-kinase (PI3K) pathway responsible in liver regeneration. Oltipraz treatment (30 mg/kg/day, for 3 days) promoted liver regeneration in PH rats, but did not increase hepatocyte growth factor production. Subcellular fractionation and electrophoretic mobility shift assays showed that oltipraz treatment increased C/EBPbeta-DNA binding activity in the liver of sham control rats and further enhanced PH-mediated nuclear translocation of C/EBPbeta. The expression of cyclin E and the activity of cyclin E-dependent kinase were both enhanced by oltipraz treatment of PH rats. The signaling pathway that controls C/EBPbeta and cyclin E were studied in H4IIE cells, a rat-derived hepatocyte cell line. Oltipraz potentiated the nuclear accumulation of C/ EBPbeta and C/EBPbeta-DNA binding activity in cells incubated in a medium containing serum. PI3K and its downstream kinase, p70S6 kinase, were both required for C/EBPbeta-dependent induction of cyclin E by oltipraz, as shown by chemical inhibition and plasmid transfection experiments. The results of this study demonstrate that oltipraz treatment enhances liver regeneration after PH, which involves activation of C/EBPbeta and C/EBPbeta-dependent cyclin E expression via the PI3K-p70S6 kinase pathway.
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Affiliation(s)
- Il Je Cho
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 151-742, Korea
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Szabo E, Soboloff J, Dziak E, Opas M. Tamoxifen-Inducible Cre-Mediated Calreticulin Excision to Study Mouse Embryonic Stem Cell Differentiation. Stem Cells Dev 2009; 18:187-93. [DOI: 10.1089/scd.2008.0064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Eva Szabo
- Laboratory Medicine and Pathobiology/Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan Soboloff
- Laboratory Medicine and Pathobiology/Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Current affiliation: Department of Biochemistry, Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Ewa Dziak
- Laboratory Medicine and Pathobiology/Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Michal Opas
- Laboratory Medicine and Pathobiology/Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
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Vlasova IA, Bohjanen PR. Posttranscriptional regulation of gene networks by GU-rich elements and CELF proteins. RNA Biol 2008; 5:201-7. [PMID: 18971639 DOI: 10.4161/rna.7056] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
GU-rich elements found in pre-mRNA and mRNA transcripts play diverse roles in the control of gene expression by regulating mRNA stability, translation and pre-mRNA processing. Regulatory GU-rich elements are highly conserved throughout evolution, and play major roles in development in diverse species from worms to mammals. The conservation of the GU-rich element allowed it to be identified as a sequence that was enriched in the 3' UTR of human transcripts that exhibited rapid mRNA decay. This element functions, at least in part, as a molecular target for members of the CELF family of RNA-binding proteins, which recruit other components of the cellular posttranscriptional gene regulatory machinery to the transcript. Depending on the context, binding to GU-rich sequences by CELF proteins direct a variety of posttranscriptional regulatory events, including deadenylation, mRNA decay, translation or pre-mRNA processing. Thus, GU-rich elements and CELF proteins serve multiple functions in gene expression regulation and define an important evolutionarily conserved posttranscriptional regulatory network.
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Affiliation(s)
- Irina A Vlasova
- Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, McGuire Translational Research Facility, Minneapolis, Minnesota 55455, USA
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Ki SH, Kim SG. Phase II enzyme induction by α-lipoic acid through phosphatidylinositol 3-kinase-dependent C/EBPs activation. Xenobiotica 2008; 38:587-604. [DOI: 10.1080/00498250802126920] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- S. H. Ki
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University , Seoul, Korea
| | - S. G. Kim
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University , Seoul, Korea
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Expression of adipogenic transcription factors in adipose tissue of fattening Wagyu and Holstein steers. Meat Sci 2008; 81:86-92. [PMID: 22063966 DOI: 10.1016/j.meatsci.2008.06.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 06/04/2008] [Accepted: 06/27/2008] [Indexed: 11/22/2022]
Abstract
In this experiment, we studied the effects of breed differences on the protein expression of adipogenic transcription factors, the C/EBP family (C/EBPα, C/EBPβ-LAP, C/EBPβ-LIP and C/EBPδ) and PPARγ, in the adipose tissues of Japanese Black (Wagyu) and Holstein steers from various anatomical sites (subcutaneous, intermuscular, and mesenteric) at different fattening periods (19 and 24 months of age). The expression of C/EBPβ-LAP and C/EBPα in the mesenteric fat tissue of Wagyu at 19 months of age was significantly higher than that of Holstein. The expression of C/EBPδ in the subcutaneous, intermuscular and mesenteric fat tissue of Wagyu at 19 months of age was significantly higher than that of Holstein. The plasma insulin concentrations of Wagyu steers at 19 months of age tended to be higher than those of Holstein. No significant differences in the expression of the adipogenic transcription factors and plasma insulin concentration were observed between the breeds at 24 months of age. These results suggest the existence of breed difference on the expression of the C/EBP family between fattening Wagyu and Holstein steers at 19 months of age, whereas breed difference might have disappeared before 24 months of age.
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Ectopic expression of cyclin D3 corrects differentiation of DM1 myoblasts through activation of RNA CUG-binding protein, CUGBP1. Exp Cell Res 2008; 314:2266-78. [PMID: 18570922 DOI: 10.1016/j.yexcr.2008.04.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/02/2008] [Accepted: 04/22/2008] [Indexed: 11/20/2022]
Abstract
Differentiation of myocytes is impaired in patients with myotonic dystrophy type 1, DM1. CUG repeat binding protein, CUGBP1, is a key regulator of translation of proteins that are involved in muscle development and differentiation. In this paper, we present evidence that RNA-binding activity of CUGBP1 and its interactions with initiation translation complex eIF2 are differentially regulated during myogenesis by specific phosphorylation and that this regulation is altered in DM1. In normal myoblasts, Akt kinase phosphorylates CUGBP1 at Ser28 and increases interactions of CUGBP1 with cyclin D1 mRNA. During differentiation, CUGBP1 is phosphorylated by cyclinD3-cdk4/6 at Ser302, which increases CUGBP1 binding with p21 and C/EBPbeta mRNAs. While cyclin D3 and cdk4 are elevated in normal myotubes; DM1 differentiating cells do not increase these proteins. In normal myotubes, CUGBP1 interacts with cyclin D3/cdk4/6 and eIF2; however, interactions of CUGBP1 with eIF2 are reduced in DM1 differentiating cells and correlate with impaired muscle differentiation in DM1. Ectopic expression of cyclin D3 in DM1 cells increases the CUGBP1-eIF2 complex, corrects expression of differentiation markers, myogenin and desmin, and enhances fusion of DM1 myoblasts. Thus, normalization of cyclin D3 might be a therapeutic approach to correct differentiation of skeletal muscle in DM1 patients.
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Dudaronek JM, Barber SA, Clements JE. CUGBP1 is required for IFNbeta-mediated induction of dominant-negative CEBPbeta and suppression of SIV replication in macrophages. THE JOURNAL OF IMMUNOLOGY 2008; 179:7262-9. [PMID: 18025168 DOI: 10.4049/jimmunol.179.11.7262] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Productive HIV replication in the CNS occurs very early after infection, yet HIV-associated cognitive disorders do not typically manifest until the development of AIDS, suggesting that mechanisms exist in the CNS to control HIV replication and associated virus-induced pathological changes during the acute and asymptomatic stages of disease. Using an established SIV/macaque model of HIV dementia, we recently demonstrated that the mechanisms regulating virus replication in the brain at these stages involve the production of IFNbeta, which induces the truncated, dominant-negative isoform of C/EBPbeta, also referred to as LIP (liver-enriched transcriptional inhibitory protein). Alternative translation of C/EBPbeta mRNA and increased production of LIP can be mediated by CUGBP1 (CUG-repeat RNA-binding protein 1). Because IFNbeta induces the inhibitory C/EBPbeta in macrophages, we considered the possibility that IFNbeta signaling regulates the activity of CUGBP1, resulting in increased expression of LIP and suppression of SIV replication. In this study, we report that IFNbeta induces LIP and suppresses active SIV replication in primary macrophages from rhesus macaques. Further, we demonstrate that IFNbeta induces the phosphorylation of CUGBP1 and the formation of CUGBP1-C/EBPbeta mRNA complexes in the human monocytic U937 cell line. Finally, we demonstrate that CUGBP1 is not only required for IFNbeta-mediated induction of LIP but also for IFNbeta-mediated suppression of SIV replication. These results suggest that CUGBP1 is a previously unrecognized downstream effector of IFNbeta signaling in primary macrophages that likely plays a pivotal role in innate immune responses that control acute HIV/SIV replication in the brain.
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Affiliation(s)
- Justyna M Dudaronek
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Bae EJ, Yang YM, Kim SG. Abrogation of Hyperosmotic Impairment of Insulin Signaling by a Novel Class of 1,2-Dithiole-3-thiones through the Inhibition of S6K1 Activation. Mol Pharmacol 2008; 73:1502-12. [DOI: 10.1124/mol.107.044347] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Bae EJ, Yang YM, Kim JW, Kim SG. Identification of a novel class of dithiolethiones that prevent hepatic insulin resistance via the adenosine monophosphate-activated protein kinase-p70 ribosomal S6 kinase-1 pathway. Hepatology 2007; 46:730-9. [PMID: 17668885 DOI: 10.1002/hep.21769] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Several established liver diseases of various causes are highly associated with hepatic insulin resistance, which is characterized by the desensitization of target cells to insulin. Peripheral insulin resistance is observed in most patients who have cirrhosis. Conversely, insulin-resistant diabetic patients are at increased risk for developing liver disease. Current therapeutic interventions in insulin resistance are limited and therefore likely to be advanced by new tailor-made drugs. Oltipraz, a prototype dithiolthione, inhibits transforming growth factor beta1 and has the ability to regenerate cirrhotic liver. We investigated the effects of oltipraz and synthetic dithiolthiones on hepatic insulin resistance and the molecular basis of action. Oltipraz and other dithiolethione compounds were tested on tumor necrosis factor alpha (TNF-alpha)-induced insulin resistance and glucose homeostasis in vitro and in vivo via immunoblotting, plasmid transfection, kinase analysis, and functional assays. Oltipraz treatment inhibited the ability of TNF-alpha to activate p70 ribosomal S6 kinase-1 (S6K1) downstream of mammalian target of rapamycin, thus preventing insulin receptor substrate-1 serine phosphorylation and protecting insulin signals. Moreover, oltipraz activated AMP-activated protein kinase (AMPK), whose inhibition by a dominant negative mutant abolished S6K1 inhibition and protected insulin signaling, indicating that AMPK activation leads to S6K1 inhibition. In hepatocyte-derived cell lines, oltipraz inhibited glucose production. Oltipraz prevented hepatic insulin resistance in C57BL/6 mice challenged with endotoxin (or TNF-alpha), leptin-deficient mice, and mice fed a high-fat diet. Synthetic dithiolethiones comparably inhibited insulin resistance. CONCLUSION Our findings led to the identification of dithiolethione compounds that prevent insulin resistance through a mechanism involving AMPK-mediated S6K1 inhibition and thereby sensitize hepatic insulin response.
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Affiliation(s)
- Eun Ju Bae
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
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Yamada T, Kawakami SI, Nakanishi N. Effects of fattening periods on the expression of adipogenic transcription factors in Wagyu beef cattle. Meat Sci 2007; 76:289-94. [DOI: 10.1016/j.meatsci.2006.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 10/28/2006] [Accepted: 11/21/2006] [Indexed: 10/23/2022]
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Karagiannides I, Thomou T, Tchkonia T, Pirtskhalava T, Kypreos KE, Cartwright A, Dalagiorgou G, Lash TL, Farmer SR, Timchenko NA, Kirkland JL. Increased CUG triplet repeat-binding protein-1 predisposes to impaired adipogenesis with aging. J Biol Chem 2006; 281:23025-33. [PMID: 16754681 DOI: 10.1074/jbc.m513187200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Preadipocyte differentiation capacity declines between middle and old age. Expression of the adipogenic transcription factors, CCAAT/enhancer-binding protein (C/EBP) alpha and peroxisome proliferator-activated receptor gamma (PPARgamma), is lower in differentiating preadipocytes from old than young animals, although no age-related changes occur in C/EBPbeta mRNA, which is upstream of C/EBPalpha and PPARgamma. C/EBPbeta-liver-enriched inhibitory protein (C/EBPbeta-LIP), a truncated C/EBPbeta isoform that is a dominant inhibitor of differentiation, increases with aging in rat fat tissue and preadipocytes. CUG triplet repeat-binding protein-1 (CUGBP1) binds to C/EBPbeta mRNA, increasing C/EBPbeta-LIP translation. Abundance and nucleotide binding activity of CUGBP1 increased with aging in preadipocytes. CUGBP1 overexpression in preadipocytes from young animals increased C/EBPbeta-LIP and impaired adipogenesis. Decreasing CUGBP1 in preadipocytes from old rats by RNA interference reduced C/EBPbeta-LIP abundance and promoted adipogenesis. Tumor necrosis factor-alpha, levels of which are elevated in fat tissue with aging, increased CUGBP1 protein, CUGBP1 binding activity, and C/EBPbeta-LIP in preadipocytes from young rats. Thus, CUGBP1 contributes to regulation of adipogenesis in primary preadipocytes and is responsive to tumor necrosis factor-alpha. With aging, preadipocyte CUGBP1 abundance and activity increases, resulting in enhanced translation of the C/EBPbeta-LIP isoform, thereby blocking effects of adipogenic transcription factors, predisposing preadipocytes from old animals to resist adipogenesis. Altered translational processing, possibly related to changes in cytokine milieu and activation of stress responses, may contribute to changes in progenitor differentiation and tissue function with aging.
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Ko MS, Lee SJ, Kim JW, Lim JW, Kim SG. DIFFERENTIAL EFFECTS OF THE OXIDIZED METABOLITES OF OLTIPRAZ ON THE ACTIVATION OF CCAAT/ENHANCER BINDING PROTEIN-β AND NF-E2-RELATED FACTOR-2 FOR GSTA2 GENE INDUCTION. Drug Metab Dispos 2006; 34:1353-60. [PMID: 16714377 DOI: 10.1124/dmd.106.009514] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Comprehensive mechanistic studies suggest that oltipraz exerts cancer chemopreventive effects through the induction of glutathione S-transferase (GST). Previously, we have shown that the activation of CCAAT/enhancer binding protein-beta (C/EBPbeta), promoted by oltipraz, contributes to the transcriptional induction of the GSTA2 gene. Studies also indicated that exposure of animals to oltipraz triggers nuclear accumulation of NF-E2-related factor-2 (Nrf2) with an increase in Nrf2's antioxidant response element (ARE) binding activity. Given the previous reports that C/EBPbeta activation contributes to oltipraz's induction of the GSTA2 gene and that Nrf2 activation by oltipraz was variable depending on the concentrations, this study investigated whether the major oxidized metabolites of oltipraz induce GSTA2 through the activation of C/EBPbeta and/or Nrf2. Immunoblot analysis revealed that M1 [4-methyl-5-(pyrazin-2-yl)-3H-1,2-dithiol-3-one] and M2 (7-methyl-6,8-bis(methylthio)H-pyrrolo[1,2-a]pyrazine), but not M3 (7-methyl-8-(methylsulfinyl)-6-(methylthio)H-pyrrolo[1,2-a]pyrazine) and M4 (7-methyl-6,8-bis(methylsulfinyl)H-pyrrolo[1,2-a]pyrazine), induced GSTA2 in H4IIE cells. M1 and M2 also increased the luciferase activity from pGL-1651, which contained the luciferase structural gene downstream of the -1.65-kilobase GSTA2 promoter region. Nuclear C/EBPbeta levels were enhanced by the metabolites but not by M3 or M4. Among the oxidized metabolites examined, only M2, which elicited cell death at a relatively high concentration, activated Nrf2, as indicated by nuclear accumulation of Nrf2 and its ARE binding activity. The present study provides evidence that M1 and M2, but not M3 and M4, induce GSTA2 and that M1 induces GSTA2 only via C/EBPbeta activation, whereas M2 does so by activating Nrf2 as well as C/EBPbeta. These results substantiate the differential effects of oltipraz's metabolites on C/EBPbeta- and/or Nrf2-mediated GSTA2 induction.
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Affiliation(s)
- Myong Suk Ko
- College of Pharmacy, National Research Laboratory, Seoul National University, Sillim-dong, Kwanak-gu, Seoul 151-742, Korea
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