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Rajamani BM, Illangeswaran RSS, Benjamin ESB, Balakrishnan B, Jebanesan DZP, Das S, Pai AA, Vidhyadharan RT, Mohan A, Karathedath S, Abraham A, Mathews V, Velayudhan SR, Balasubramanian P. Modulating retinoid-X-receptor alpha (RXRA) expression sensitizes chronic myeloid leukemia cells to imatinib in vitro and reduces disease burden in vivo. Front Pharmacol 2023; 14:1187066. [PMID: 37324449 PMCID: PMC10264673 DOI: 10.3389/fphar.2023.1187066] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/18/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction: The ligand-activated transcription factors, nuclear hormone receptors (NHRs), remain unexplored in hematological malignancies except for retinoic acid receptor alpha (RARA). Methods: Here we profiled the expression of various NHRs and their coregulators in Chronic myeloid leukemia (CML) cell lines and identified a significant differential expression pattern between inherently imatinib mesylate (IM)-sensitive and resistant cell lines. Results: Retinoid-X-receptor alpha (RXRA) was downregulated in CML cell lines inherently resistant to IM and in primary CML CD34+ cells. Pre-treatment with clinically relevant RXRA ligands improved sensitivity to IM in-vitro in both CML cell lines and primary CML cells. This combination effectively reduced the viability and colony-forming capacity of CML CD34+ cells in-vitro. In-vivo, this combination reduced leukemic burden and prolonged survival. Overexpression (OE) of RXRA inhibited proliferation and improved sensitivity to IM in-vitro. In-vivo, RXRA OE cells showed reduced engraftment of cells in the bone marrow, improved sensitivity to IM, and prolonged survival. Both RXRA OE and ligand treatment markedly reduced BCR::ABL1 downstream kinase activation, activating apoptotic cascades and improving sensitivity to IM. Importantly, RXRA OE also led to the disruption of the oxidative capacity of these cells. Conclusion: Combining IM with clinically available RXRA ligands could form an alternative treatment strategy in CML patients with suboptimal response to IM.
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Affiliation(s)
- Bharathi M. Rajamani
- Department of Haematology, Christian Medical College, Vellore, India
- Department of Biotechnology, Thiruvalluvar University, Vellore, India
| | | | - Esther Sathya Bama Benjamin
- Department of Haematology, Christian Medical College, Vellore, India
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India
| | - Balaji Balakrishnan
- Department of Haematology, Christian Medical College, Vellore, India
- Department of Integrative Biology, School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | | | - Saswati Das
- Department of Haematology, Christian Medical College, Vellore, India
- Department of Biotechnology, Thiruvalluvar University, Vellore, India
| | - Aswin Anand Pai
- Department of Haematology, Christian Medical College, Vellore, India
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India
| | | | - Ajith Mohan
- Department of Haematology, Christian Medical College, Vellore, India
| | | | - Aby Abraham
- Department of Haematology, Christian Medical College, Vellore, India
| | - Vikram Mathews
- Department of Haematology, Christian Medical College, Vellore, India
| | - Shaji R. Velayudhan
- Department of Haematology, Christian Medical College, Vellore, India
- Centre for Stem Cell Research (CSCR), A Unit of InStem Bengaluru, Christian Medical College Campus, Vellore, India
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2
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Morthorst JE, Holbech H, De Crozé N, Matthiessen P, LeBlanc GA. Thyroid-like hormone signaling in invertebrates and its potential role in initial screening of thyroid hormone system disrupting chemicals. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2023; 19:63-82. [PMID: 35581168 PMCID: PMC10083991 DOI: 10.1002/ieam.4632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/30/2022] [Accepted: 05/12/2022] [Indexed: 05/07/2023]
Abstract
This review examines the presence and evolution of thyroid-like systems in selected aquatic invertebrates to determine the potential use of these organisms in screens for vertebrate thyroid hormone axis disrupting chemicals (THADCs). Such a screen might support the phasing out of some vertebrate testing. Although arthropods including crustaceans do not contain a functional thyroid signaling system, elements of such a system exist in the aquatic phyla mollusks, echinoderms, tunicates, and cephalochordates. These phyla can synthesize thyroid hormone, which has been demonstrated in some groups to induce the nuclear thyroid hormone receptor (THR). Thyroid hormone may act in these phyla through interaction with a membrane integrin receptor. Thyroid hormone regulates inter alia metamorphosis but, unlike in vertebrates, this does not occur via receptor activation by the ligands triiodothyronine (T3) and thyroxine (T4). Instead, the unliganded nuclear receptor itself controls metamorphosis in mollusks, echinoderms, and tunicates, whereas the T3 derivative tri-iodothyroacetic acid (TRIAC) acts as a THR ligand in cephalochordates. In view of this, it may be possible to develop an invertebrate-based screen that is sensitive to vertebrate THADCs that interfere with thyroid hormone synthesis or metabolism along with interaction with membrane receptors. The review makes some recommendations for the need to develop an appropriate test method. Integr Environ Assess Manag 2023;19:63-82. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
| | - Henrik Holbech
- Department of BiologyUniversity of Southern DenmarkOdense MDenmark
| | - Noémie De Crozé
- Laboratoire Recherche Environnementale, L'ORÉAL Recherche & InnovationAulnay‐sous‐BoisFrance
| | | | - Gerald A. LeBlanc
- Department of Biological SciencesNorth Carolina State UniversityRaleighNorth CarolinaUSA
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3
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Martinez ME, Pinz I, Preda M, Norton CR, Gridley T, Hernandez A. DIO3 protects against thyrotoxicosis-derived cranio-encephalic and cardiac congenital abnormalities. JCI Insight 2022; 7:e161214. [PMID: 36166296 PMCID: PMC9675556 DOI: 10.1172/jci.insight.161214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 09/21/2022] [Indexed: 12/15/2022] Open
Abstract
Maternal hyperthyroidism is associated with an increased incidence of congenital abnormalities at birth, but it is not clear which of these defects arise from a transient developmental excess of thyroid hormone and which depend on pregnancy stage, antithyroid drug choice, or unwanted subsequent fetal hypothyroidism. To address this issue, we studied a mouse model of comprehensive developmental thyrotoxicosis secondary to a lack of type 3 deiodinase (DIO3). Dio3-/- mice exhibited reduced neonatal viability on most genetic backgrounds and perinatal lethality on a C57BL/6 background. Dio3-/- mice exhibited severe growth retardation during the neonatal period and cartilage loss. Mice surviving after birth manifested brain and cranial dysmorphisms, severe hydrocephalus, choanal atresia, and cleft palate. These abnormalities were noticeable in C57BL/6J Dio3-/- mice at fetal stages, in addition to a thyrotoxic heart with septal defects and thin ventricular walls. Our findings stress the protecting role of DIO3 during development and support the hypothesis that human congenital abnormalities associated with hyperthyroidism during pregnancy are caused by transient thyrotoxicosis before clinical intervention. Our results also suggest thyroid hormone involvement in the etiology of idiopathic pathologies including cleft palate, choanal atresia, Chiari malformations, Kaschin-Beck disease, and Temple and other cranio-encephalic and heart syndromes.
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Affiliation(s)
- M. Elena Martinez
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
| | - Ilka Pinz
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, Maine, USA
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Marilena Preda
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
| | - Christine R. Norton
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
| | - Thomas Gridley
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, Maine, USA
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Arturo Hernandez
- Center for Molecular Medicine, MaineHealth Institute for Research, MaineHealth, Scarborough, Maine, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, Maine, USA
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, USA
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4
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Giguère V, Evans RM. Chronicle of a discovery: the retinoic acid receptor. J Mol Endocrinol 2022; 69:T1-T11. [PMID: 35900848 DOI: 10.1530/jme-22-0117] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 06/18/2022] [Indexed: 11/08/2022]
Abstract
The landmark 1987 discovery of the retinoic acid receptor (RAR) came as a surprise, uncovering a genomic kinship between the fields of vitamin A biology and steroid receptors. This stunning breakthrough triggered a cascade of studies to deconstruct the roles played by the RAR and its natural and synthetic ligands in embryonic development, skin, growth, physiology, vision, and disease as well as providing a template to elucidate the molecular mechanisms by which nuclear receptors regulate gene expression. In this review, written from historic and personal perspectives, we highlight the milestones that led to the discovery of the RAR and the subsequent studies that enriched our knowledge of the molecular mechanisms by which a low-abundant dietary compound could be so essential to the generation and maintenance of life itself.
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Affiliation(s)
- Vincent Giguère
- Goodman Cancer Institute, McGill University, Montréal, Quebec, Canada
- Department of Biochemistry, McGill University, Montréal, Quebec, Canada
| | - Ronald M Evans
- The Salk Institute for Biological Studies, La Jolla, California, USA
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5
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Human Cytomegalovirus Induces Vitamin-D Resistance In Vitro by Dysregulating the Transcriptional Repressor Snail. Viruses 2022; 14:v14092004. [PMID: 36146811 PMCID: PMC9505537 DOI: 10.3390/v14092004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 12/02/2022] Open
Abstract
Vitamin-D supplementation is considered to play a beneficial role against multiple viruses due to its immune-regulating and direct antimicrobial effects. In contrast, the human cytomegalovirus (HCMV) has shown to be resistant to treatment with vitamin D in vitro by downregulation of the vitamin-D receptor. In this study, we aimed to elucidate the mechanism and possible biological consequences of vitamin-D resistance during HCMV infection. Mechanistically, HCMV induced vitamin-D resistance by downregulating the vitamin-D receptor (VDR) within hours of lytic infection. We found that the VDR was inhibited at the promoter level, and treatment with histone deacetylase inhibitors could restore VDR expression. VDR downregulation highly correlated with the upregulation of the transcriptional repressor Snail1, a mechanism likely contributing to the epigenetic inactivation of the VDR promoter, since siRNA-mediated knockdown of Snail partly restored levels of VDR expression. Finally, we found that direct addition of the vitamin-D-inducible antimicrobial peptide LL-37 strongly and significantly reduced viral titers in infected fibroblasts, highlighting VDR biological relevance and the potential of vitamin-D-inducible peptides for the antiviral treatment of vitamin-D deficient patients.
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6
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Heckert A, Dahal L, Tjian R, Darzacq X. Recovering mixtures of fast-diffusing states from short single-particle trajectories. eLife 2022; 11:e70169. [PMID: 36066004 PMCID: PMC9451534 DOI: 10.7554/elife.70169] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/04/2022] [Indexed: 12/15/2022] Open
Abstract
Single-particle tracking (SPT) directly measures the dynamics of proteins in living cells and is a powerful tool to dissect molecular mechanisms of cellular regulation. Interpretation of SPT with fast-diffusing proteins in mammalian cells, however, is complicated by technical limitations imposed by fast image acquisition. These limitations include short trajectory length due to photobleaching and shallow depth of field, high localization error due to the low photon budget imposed by short integration times, and cell-to-cell variability. To address these issues, we investigated methods inspired by Bayesian nonparametrics to infer distributions of state parameters from SPT data with short trajectories, variable localization precision, and absence of prior knowledge about the number of underlying states. We discuss the advantages and disadvantages of these approaches relative to other frameworks for SPT analysis.
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Affiliation(s)
- Alec Heckert
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
| | - Liza Dahal
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
- CIRM Center of Excellence, University of California, BerkeleyBerkeleyUnited States
| | - Robert Tjian
- CIRM Center of Excellence, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteBerkeleyUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, University of California, BerkeleyBerkeleyUnited States
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7
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Brtko J, Dvorak Z. Natural and synthetic retinoid X receptor ligands and their role in selected nuclear receptor action. Biochimie 2020; 179:157-168. [PMID: 33011201 DOI: 10.1016/j.biochi.2020.09.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/22/2020] [Accepted: 09/30/2020] [Indexed: 02/06/2023]
Abstract
Important key players in the regulatory machinery within the cells are nuclear retinoid X receptors (RXRs), which compose heterodimers in company with several diverse nuclear receptors, playing a role as ligand inducible transcription factors. In general, nuclear receptors are ligand-activated, transcription-modulating proteins affecting transcriptional responses in target genes. RXR molecules forming permissive heterodimers with disparate nuclear receptors comprise peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptor (FXR), pregnane X receptor (PXR) and constitutive androstan receptor (CAR). Retinoid receptors (RARs) and thyroid hormone receptors (TRs) may form conditional heterodimers, and dihydroxyvitamin D3 receptor (VDR) is believed to form nonpermissive heterodimer. Thus, RXRs are the important molecules that are involved in control of many cellular functions in biological processes and diseases, including cancer or diabetes. This article summarizes both naturally occurring and synthetic ligands for nuclear retinoid X receptors and describes, predominantly in mammals, their role in molecular mechanisms within the cells. A focus is also on triorganotin compounds, which are high affinity RXR ligands, and finally, we present an outlook on human microbiota as a potential source of RXR activators. Nevertheless, new synthetic rexinoids with better retinoid X receptor activity and lesser side effects are highly required.
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Affiliation(s)
- Julius Brtko
- Institute of Experimental Endocrinology, Biomedical Center of the Slovak Academy of Sciences, Dubravska cesta 9, 845 05, Bratislava, Slovak Republic.
| | - Zdenek Dvorak
- Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Slechtitelu 11, 783 71, Olomouc, Czech Republic
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8
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Martinez ME, Lary CW, Karaczyn AA, Griswold MD, Hernandez A. Spermatogonial Type 3 Deiodinase Regulates Thyroid Hormone Target Genes in Developing Testicular Somatic Cells. Endocrinology 2019; 160:2929-2945. [PMID: 31621880 PMCID: PMC6853691 DOI: 10.1210/en.2019-00259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022]
Abstract
Premature overexposure to thyroid hormone causes profound effects on testis growth, spermatogenesis, and male fertility. We used genetic mouse models of type 3 deiodinase (DIO3) deficiency to determine the genetic programs affected by premature thyroid hormone action and to define the role of DIO3 in regulating thyroid hormone economy in testicular cells. Gene expression profiling in the neonatal testis of DIO3-deficient mice identified 5699 differentially expressed genes. Upregulated and downregulated genes were, respectively, involved according to DAVID analysis with cell differentiation and proliferation. They included anti-Müllerian hormone and genes involved in the formation of the blood-testis barrier, which are specific to Sertoli cells (SCs). They also included steroidogenic genes, which are specific to Leydig cells. Comparison with published data sets of genes enriched in SCs and spermatogonia, and responsive to retinoic acid (RA), identified a subset of genes that were regulated similarly by RA and thyroid hormone. This subset of genes showed an expression bias, as they were downregulated when enriched in spermatogonia and upregulated when enriched in SCs. Furthermore, using a genetic approach, we found that DIO3 is not expressed in SCs, but spermatogonia-specific inactivation of DIO3 led to impaired testis growth, reduced SC number, decreased cell proliferation and, especially during neonatal development, altered gene expression specific to somatic cells. These findings indicate that spermatogonial DIO3 protects testicular cells from untimely thyroid hormone signaling and demonstrate a mechanism of cross-talk between somatic and germ cells in the neonatal testis that involves the regulation of thyroid hormone availability and action.
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Affiliation(s)
- M Elena Martinez
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, Maine
| | - Christine W Lary
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, Maine
- Graduate School for Biomedical Science and Engineering, University of Maine, Orono, Maine
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts
| | - Aldona A Karaczyn
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, Maine
| | - Michael D Griswold
- School for Molecular Sciences, Washington State University, Pullman, Washington
- Center for Reproductive Biology, Washington State University, Pullman, Washington
| | - Arturo Hernandez
- Center for Molecular Medicine, Maine Medical Center Research Institute, Maine Medical Center, Scarborough, Maine
- Graduate School for Biomedical Science and Engineering, University of Maine, Orono, Maine
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts
- Correspondence: Arturo Hernandez, PhD, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, Maine 04074. E-mail:
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9
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Multi-Omics Analysis Reveals Up-Regulation of APR Signaling, LXR/RXR and FXR/RXR Activation Pathways in Holstein Dairy Cows Exposed to High-Altitude Hypoxia. Animals (Basel) 2019; 9:ani9070406. [PMID: 31266191 PMCID: PMC6680605 DOI: 10.3390/ani9070406] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Blood has been widely collected and analyzed for diagnosing and monitoring diseases in human beings and animals. A range of plasma proteins and peptides were set as biomarkers for pathological and physiological status. Previous researchers have explored how humans, pigs, dogs, and horses adapt to hypoxia at high altitudes. Additionally, the mechanism of hypoxia adaptation in human, mice, and shrimp was studied by proteomics. However, information on the adaptation mechanism of Holstein cows introduced to high altitudes is limited. The present study was conducted to the adaptation mechanism of Holstein dairy cows to high-altitude hypoxia by miRNA microarray analysis and the isobaric tags for relative and absolute quantitation (iTRAQ) iTRAQ technology. Based on the obtained results, Holstein dairy cows transported to Nyingchi may adapt to the high-altitude hypoxia through regulation of inflammatory homeostasis by up-regulating the acute phase response (APR) APR and activation of the liver X receptor/retinoid X receptor (LXR/RXR)LXR/RXR and farnesoid X receptor/ retinoid X receptor (FXR/RXR) FXR/RXR pathways. Abstract Changes in the environment such as high-altitude hypoxia (HAH) high-altitude hypoxia can lead to adaptive changes in the blood system of mammals. However, there is limited information about the adaptation of Holstein dairy cows introduced to high-altitude areas. This study used 12 multiparous Holstein dairy cows (600 ± 55 kg, average three years old) exposed to HAH conditions in Nyingchi of Tibet (altitude 3000 m) and HAH-free conditions in Shenyang (altitude 50 m). The miRNA microarray analysis and iTRAQ proteomics approach (accepted as more suitable for accurate and comprehensive prediction of miRNA targets) were applied to explore the differences in the plasma proteomic and miRNA profiles in Holstein dairy cows. A total of 70 differential miRNAs (54 up-regulated, Fold change (FC) FC > 2, and 16 down-regulated, FC < 0.5) and 226 differential proteins (132 up-regulated, FC > 1.2, and 94 down-regulated, FC < 0.8) were found in the HAH-stressed group compared with the HAH-free group. Integrative analysis of proteomic and miRNA profiles demonstrated the biological processes associated with differential proteins were the immune response, complement activation, protein activation, and lipid transport. The integrative analysis of canonical pathways were most prominently associated with the APR signaling (z = 1.604), and LXR/RXR activation (z = 0.365), and FXR/RXR activation (z = 0.446) pathways. The current results indicated that Holstein dairy cows exposed to HAH could adapt to high-altitude hypoxia by up-regulating the APR, activating the LXR/RXR and FXE/RXR pathways.
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10
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Ramírez-Tejero JA, Martínez-Lara E, Rus A, Camacho MV, Del Moral ML, Siles E. Insight into the biological pathways underlying fibromyalgia by a proteomic approach. J Proteomics 2018; 186:47-55. [DOI: 10.1016/j.jprot.2018.07.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/16/2018] [Accepted: 07/16/2018] [Indexed: 12/18/2022]
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Taylor E, Heyland A. Evolution of thyroid hormone signaling in animals: Non-genomic and genomic modes of action. Mol Cell Endocrinol 2017; 459:14-20. [PMID: 28549993 DOI: 10.1016/j.mce.2017.05.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 01/02/2023]
Abstract
Much research has focused on vertebrate thyroid hormone (TH) synthesis and their function in development and metabolism. While important differences in TH synthesis and signaling exist, comparative studies between vertebrates fail to explain the evolutionary origins of this important regulatory axis. For that, one needs to make sense out of the diverse TH effects which have been described in invertebrate phyla but for which a mechanistic understanding is largely missing. Almost every major group of non-vertebrate animals possesses the capability to synthesize and metabolize thyroid hormones and there is evidence for a nuclear thyroid hormone receptor mediated mechanism in the bilateria, especially in molluscs, echinoderms, cephalochordates and ascidians. Still, genomic pathways cannot fully explain many observed effects of thyroid hormones in groups such as cnidarians, molluscs, and echinoderms and it is therefore possible that TH may signal via other mechanisms, such as non-genomic signaling systems via membrane bound or cytoplasmic receptors. Here we provide a brief review of TH actions in selected invertebrate species and discuss the hypothesis that non-genomic TH action may have played a critical role in TH signaling throughout animal evolution.
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Affiliation(s)
- Elias Taylor
- University of Guelph, Integrative Biology, Canada
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12
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Niu H, Fujiwara H, di Martino O, Hadwiger G, Frederick TE, Menéndez-Gutiérrez MP, Ricote M, Bowman GR, Welch JS. Endogenous retinoid X receptor ligands in mouse hematopoietic cells. Sci Signal 2017; 10:10/503/eaan1011. [PMID: 29089448 DOI: 10.1126/scisignal.aan1011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The retinoid X receptor α (RXRA) has been implicated in diverse hematological processes. To identify natural ligands of RXRA that are present in hematopoietic cells, we adapted an upstream activation sequence-green fluorescent protein (UAS-GFP) reporter mouse to detect natural RXRA ligands in vivo. We observed reporter activity in diverse types of hematopoietic cells in vivo. Reporter activity increased during granulocyte colony-stimulating factor (G-CSF)-induced granulopoiesis and after phenylhydrazine (PHZ)-induced anemia, suggesting the presence of dynamically regulated natural RXRA ligands in hematopoietic cells. Mouse plasma activated Gal4-UAS reporter cells in vitro, and plasma from mice treated with G-CSF or PHZ recapitulated the patterns of reporter activation that we observed in vivo. Plasma from mice with dietary vitamin A deficiency only mildly reduced RXRA reporter activity, whereas plasma from mice on a fatty acid restriction diet reduced reporter activity, implicating fatty acids as plasma RXRA ligands. Through differential extraction coupled with mass spectrometry, we identified the long-chain fatty acid C24:5 as a natural RXRA ligand that was greatly increased in abundance in response to hematopoietic stress. Together, these data suggest that natural RXRA ligands are present and dynamically increased in abundance in mouse hematopoietic cells in vivo.
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Affiliation(s)
- Haixia Niu
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hideji Fujiwara
- Diabetic Cardiovascular Disease Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Orsola di Martino
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gayla Hadwiger
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas E Frederick
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - María P Menéndez-Gutiérrez
- Myocardial Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid 28029, Spain
| | - Mercedes Ricote
- Myocardial Pathophysiology Area, Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid 28029, Spain
| | - Gregory R Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John S Welch
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Regulation of type 1 iodothyronine deiodinase by LXRα. PLoS One 2017; 12:e0179213. [PMID: 28617824 PMCID: PMC5472309 DOI: 10.1371/journal.pone.0179213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 05/25/2017] [Indexed: 11/24/2022] Open
Abstract
The iodothyronine deiodinases are selenoenzymes that regulate the activity of thyroid hormone via specific inner- or outer-ring deiodination. In humans, type 1 deiodinase (D1) is highly expressed in the liver, but the mechanism by which its gene expression is regulated remains to be elucidated. Liver X receptor α (LXRα), a transcription factor of the nuclear receptor superfamily, is highly expressed in the liver, where it functions as a sensor for excess intracellular oxysterols. LXRα interacts with other nuclear receptors on promoters of genes that contain a binding core sequence for nuclear receptors. In addition, it is reported that the promoter of the gene encoding human D1 (hDIO1) contains the core sequence for one of nuclear receptors, thyroid hormone receptor (TR). We investigated the involvement of LXRα in the regulation of hDIO1, in the liver. We performed hDIO1 promoter–reporter assays using a synthetic LXR agonist, T0901317, and compared promoter activity between a human liver carcinoma cell line, HepG2, and a clone of human embryonic kidney cells, TSA201. We defined the region between nucleotides −131 and −114, especially nucleotides −126 and −125, of the hDIO1 promoter as critical for basal and LXRα-mediated specific transcriptional activation in HepG2 cells. An increase in hDIO1 expression was observed in LXRα-stimulated cells, but absent in cycloheximide-treated cells, indicating that new protein synthesis is required for LXRα-mediated regulation of hDIO1. On the other hand, electrophoretic mobility shift assays revealed that LXRα and RXRα bound to the hDIO1 promoter. We also demonstrated that LXRα and TRβ compete with each other on this specific region of the promoter. In conclusion, our results indicated that LXRα plays a specific and important role in activation of TH by regulating D1, and that LXRα binds to and regulates the hDIO1 promoter, competing with TRβ on specific sequences within the promoter.
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Isotretinoin as a Possible Environmental Trigger to Autoimmunity in Genetically Susceptible Patients. Case Rep Pediatr 2017; 2017:4207656. [PMID: 28458939 PMCID: PMC5385229 DOI: 10.1155/2017/4207656] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/15/2017] [Indexed: 11/22/2022] Open
Abstract
Introduction. Isotretinoin is commonly used to treat cystic acne. Definitive mechanisms of action for isotretinoin are not known though despite many side effects having been documented. Various case reports have noted autoimmune diseases succeeding isotretinoin treatment. Case Report. A 16-year-old female presents with symptoms of tremors, lack of focus, sleeplessness, emotional liability, bulging eyes, loose stools, heat intolerance, and missed menstrual periods. Symptoms manifested shortly after the patient finished a course of oral isotretinoin treatment for acne. Physical exam showed resting tremors, bilateral proptosis, hyperactivity, and rapid speech. A diagnosis of Graves' Disease was made by correlating symptoms, physical exam findings, ultrasound, and positive family history of autoimmune thyroid disease. Conclusion. Emergence of autoimmune thyroid diseases depends upon genetic predisposition and environmental triggers. Mechanism of action for isotretinoin is not known but the drug may play a role in triggering autoimmunity in genetically susceptible individuals.
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Hamada T, Sugaya M, Tokura Y, Ohtsuka M, Tsuboi R, Nagatani T, Tani M, Setoyama M, Matsushita S, Kawai K, Yonekura K, Yoshida T, Saida T, Iwatsuki K. Phase I/II study of the oral retinoid X receptor agonist bexarotene in Japanese patients with cutaneous T-cell lymphomas. J Dermatol 2016; 44:135-142. [DOI: 10.1111/1346-8138.13542] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/28/2016] [Indexed: 11/27/2022]
Affiliation(s)
- Toshihisa Hamada
- Department of Dermatology; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama Japan
| | - Makoto Sugaya
- Department of Dermatology; Faculty of Medicine; University of Tokyo; Tokyo Japan
| | - Yoshiki Tokura
- Department of Dermatology; Hamamatsu University School of Medicine; Shizuoka Japan
| | - Mikio Ohtsuka
- Department of Dermatology; Fukushima Medical University; Fukushima Japan
| | - Ryoji Tsuboi
- Department of Dermatology; Tokyo Medical University; Tokyo Japan
| | - Tetsuo Nagatani
- Department of Dermatology; Tokyo Medical University Hachioji Medical Center; Tokyo Japan
| | - Mamori Tani
- Department of Dermatology; Osaka University Graduate School of Medicine; Osaka Japan
| | - Mitsuru Setoyama
- Department of Dermatology; Faculty of Medicine; University of Miyazaki; Miyazaki Japan
| | - Shigeto Matsushita
- Department of Dermatology; Kagoshima University Graduate School of Medical and Dental Sciences; Kagoshima Japan
| | - Kazuhiro Kawai
- Department of Dermatology; Kagoshima University Graduate School of Medical and Dental Sciences; Kagoshima Japan
| | - Kentaro Yonekura
- Department of Dermatology; Imamura Bun-in Hospital; Kagoshima Japan
| | | | - Toshiaki Saida
- Department of Dermatology; Shinshu University; Nagano Japan
| | - Keiji Iwatsuki
- Department of Dermatology; Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences; Okayama Japan
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Jones BG, Penkert RR, Xu B, Fan Y, Neale G, Gearhart PJ, Hurwitz JL. Binding of estrogen receptors to switch sites and regulatory elements in the immunoglobulin heavy chain locus of activated B cells suggests a direct influence of estrogen on antibody expression. Mol Immunol 2016; 77:97-102. [PMID: 27494228 DOI: 10.1016/j.molimm.2016.07.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 07/17/2016] [Accepted: 07/21/2016] [Indexed: 12/31/2022]
Abstract
Females and males differ in antibody isotype expression patterns and in immune responses to foreign- and self-antigens. For example, systemic lupus erythematosus is a condition that associates with the production of isotype-skewed anti-self antibodies, and exhibits a 9:1 female:male disease ratio. To explain differences between B cell responses in males and females, we sought to identify direct interactions of the estrogen receptor (ER) with the immunoglobulin heavy chain locus. This effort was encouraged by our previous identification of estrogen response elements (ERE) in heavy chain switch (S) regions. We conducted a full-genome chromatin immunoprecipitation analysis (ChIP-seq) using DNA from LPS-activated B cells and an ERα-specific antibody. Results revealed ER binding to a wide region of DNA, spanning sequences from the JH cluster to Cδ, with peaks in Eμ and Sμ sites. Additional peaks of ERα binding were coincident with hs1,2 and hs4 sites in the 3' regulatory region (3'RR) of the heavy chain locus. This first demonstration of direct binding of ER to key regulatory elements in the immunoglobulin locus supports our hypothesis that estrogen and other nuclear hormone receptors and ligands may directly influence antibody expression and class switch recombination (CSR). Our hypothesis encourages the conduct of new experiments to evaluate the consequences of ER binding. A better understanding of ER:DNA interactions in the immunoglobulin heavy chain locus, and respective mechanisms, may ultimately translate to better control of antibody expression, better protection against pathogens, and prevention of pathologies caused by auto-immune disease.
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Affiliation(s)
- Bart G Jones
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Rhiannon R Penkert
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Beisi Xu
- Department of Computational Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yiping Fan
- Department of Computational Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Geoff Neale
- Hartwell Center, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Patricia J Gearhart
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Julia L Hurwitz
- Department of Infectious Diseases, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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17
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Hurwitz JL, Penkert RR, Xu B, Fan Y, Partridge JF, Maul RW, Gearhart PJ. Hotspots for Vitamin-Steroid-Thyroid Hormone Response Elements Within Switch Regions of Immunoglobulin Heavy Chain Loci Predict a Direct Influence of Vitamins and Hormones on B Cell Class Switch Recombination. Viral Immunol 2016; 29:132-6. [PMID: 26741514 DOI: 10.1089/vim.2015.0104] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Vitamin A deficiencies are common throughout the world and have a significant negative influence on immune protection against viral infections. Mouse models demonstrate that the production of IgA, a first line of defense against viruses at mucosal sites, is inhibited in the context of vitamin A deficiency. In vitro, the addition of vitamin A to activated B cells can enhance IgA expression, but downregulate IgE. Previous reports have demonstrated that vitamin A modifies cytokine patterns, and in so doing may influence antibody isotype expression by an indirect mechanism. However, we have now discovered hundreds of potential response elements among Sμ, Sɛ, and Sα switch sites within immunoglobulin heavy chain loci. These hotspots appear in both mouse and human loci and include targets for vitamin receptors and related proteins (e.g., estrogen receptors) in the nuclear receptor superfamily. Full response elements with direct repeats are relatively infrequent or absent in Sγ regions although half-sites are present. Based on these results, we pose a hypothesis that nuclear receptors have a direct effect on the immunoglobulin heavy chain class switch recombination event. We propose that vitamin A may alter S site accessibility to activation-induced deaminase and nonhomologous end-joining machinery, thereby influencing the isotype switch, antibody production, and protection against viral infections at mucosal sites.
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Affiliation(s)
- Julia L Hurwitz
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,2 Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Rhiannon R Penkert
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Beisi Xu
- 3 Department of Computational Biology, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Yiping Fan
- 3 Department of Computational Biology, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Janet F Partridge
- 4 Department of Pathology, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Robert W Maul
- 5 National Institute on Aging, National Institutes of Health , Baltimore, Maryland
| | - Patricia J Gearhart
- 5 National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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18
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Surman SL, Penkert RR, Jones BG, Sealy RE, Hurwitz JL. Vitamin Supplementation at the Time of Immunization with a Cold-Adapted Influenza Virus Vaccine Corrects Poor Mucosal Antibody Responses in Mice Deficient for Vitamins A and D. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2016; 23:219-27. [PMID: 26740391 PMCID: PMC4783424 DOI: 10.1128/cvi.00739-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 12/28/2015] [Indexed: 12/21/2022]
Abstract
Vitamin A and D deficiencies and insufficiencies are prevalent worldwide in developed and developing countries. Vitamin metabolites are functionally intertwined in that they are high-affinity ligands for related receptors of the nuclear receptor superfamily. The effects of vitamin A deficiencies (VAD) on antibody responses to respiratory virus vaccines have already been demonstrated. Of particular concern was the reduction in IgA, a first line of defense against pathogens in the respiratory tract. Here, we describe the individual and combined effects of vitamin A and D deficiencies in mice immunized with an attenuated influenza virus vaccine. Relative to VAD, vitamin D deficiency (VDD) had a limited effect, but double deficiencies for vitamins A and D (VAD+VDD) further reduced antibody responses in the respiratory tract. The administration of supplemental vitamins A and D to VAD+VDD mice at the time of vaccination restored responses in a dose-dependent manner. Results suggest that vitamin supplementation programs may be beneficial in a clinical setting to promote healthy immune responses to respiratory virus vaccines in vitamin-deficient individuals.
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Affiliation(s)
- S L Surman
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - R R Penkert
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - B G Jones
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - R E Sealy
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - J L Hurwitz
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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Fattori J, Campos JLO, Doratioto TR, Assis LM, Vitorino MT, Polikarpov I, Xavier-Neto J, Figueira ACM. RXR agonist modulates TR: corepressor dissociation upon 9-cis retinoic acid treatment. Mol Endocrinol 2014; 29:258-73. [PMID: 25541638 DOI: 10.1210/me.2014-1251] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transcriptional regulation controlled by thyroid hormone receptor (TR) drives events such as development, differentiation, and metabolism. TRs may act either as homodimers or as heterodimers with retinoid X receptor (RXR). Thyroid hormone T3 preferentially binds TR-RXR heterodimers, which activate transcription through coactivator recruitment. However, it is unclear whether TR-RXR heterodimers may also be responsive to the canonical RXR agonist 9-cis retinoic acid (9C) in the context of physiological gene regulation. New structural studies suggest that 9C promotes the displacement of bound coactivators from the heterodimer, modifying TR-RXR activity. To shed light on the molecular mechanisms that control TR-RXR function, we used biophysical approaches to characterize coregulator recruitment to TR-TR or to TR-RXR in the presence of T3 and/or 9C as well as cell-based assays to establish the functional significance of biophysical findings. Using cell-based and fluorescence assays with mutant and wild-type TR, we show that 9C does indeed have a function in the TR-RXR heterodimer context, in which it induces the release of corepressors. Furthermore, we show that 9C does not promote detectable conformational changes in the structure of the TR-RXR heterodimer and does not affect coactivator recruitment. Finally, our data support the view that DNA binding domain and Hinge regions are important to set up NR-coactivator binding interfaces. In summary, we showed that the RXR agonist 9C can regulate TR function through its modulation of corepressor dissociation.
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Affiliation(s)
- Juliana Fattori
- Centro Nacional de Pesquisa em Energia e Materiais (J.F., J.L.O.C., T.R.D., L.M.A., M.T.V., J.X.-N., A.C.M.F.), Laboratório Nacional de Biociências, Campinas SP, 13083-970, Brazil; and Instituto de Física de São Carlos (I.P.), Universidade de São Paulo, São Carlos SP, 13560-970, Brazil
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20
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Paquette MA, Atlas E, Wade MG, Yauk CL. Thyroid hormone response element half-site organization and its effect on thyroid hormone mediated transcription. PLoS One 2014; 9:e101155. [PMID: 24971931 PMCID: PMC4074170 DOI: 10.1371/journal.pone.0101155] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/03/2014] [Indexed: 02/03/2023] Open
Abstract
Thyroid hormone (TH) exerts its effects by binding to the thyroid hormone receptor (TR), which binds to TH response elements (TREs) to regulate target gene expression. We investigated the relative ability of liganded homodimers TR and retinoid X receptor (RXR), and the heterodimer TR/RXR, to regulate gene expression for the TRE half-site organizations: direct repeat 4 (DR4), inverted repeat 0 (IR0) and everted repeat 6 (ER6). Luciferase reporter assays using a DR4 TRE suggest that both the TR homodimer and TR/RXR heterodimer regulate luciferase expression in the presence of their respective ligands. However, in the presence of the IR0 TRE, transfection with TR/RXR and RXR alone increased luciferase activity and there was no effect of TR alone. The presence of 9-cis-retinoic acid was necessary for luciferase expression, whereas TH treatment alone was insufficient. For the ER6 TRE, transfection with TR/RXR, TR alone and RXR alone (in the presence of their respective ligands) all caused a significant increase in luciferase activity. When both ligands were present, transfection with both TR/RXR caused more activation. Finally, we investigated the efficacy of the TR-antagonist 1–850 in inhibiting transcription by TR or TR/RXR at DR4 and ER6 TREs. We found that 1–850 did not suppress luciferase activation in the presence of TR/RXR for the ER6 TRE, suggesting conformational changes of the ligand binding domain of the TR when bound to different TRE half-site organizations. Collectively, the findings indicate that there are fundamental differences between TRE configurations that affect nuclear receptor interactions with the response element and ability to bind ligands and antagonists.
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Affiliation(s)
- Martin A. Paquette
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Mike G. Wade
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
- * E-mail:
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21
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Evans RM, Mangelsdorf DJ. Nuclear Receptors, RXR, and the Big Bang. Cell 2014; 157:255-66. [PMID: 24679540 DOI: 10.1016/j.cell.2014.03.012] [Citation(s) in RCA: 805] [Impact Index Per Article: 80.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/11/2014] [Indexed: 12/15/2022]
Abstract
Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism.
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Affiliation(s)
- Ronald M Evans
- Howard Hughes Medical Institute; The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - David J Mangelsdorf
- Howard Hughes Medical Institute; The Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA.
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22
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Potential retinoid x receptor agonists for treating Alzheimer's disease from traditional chinese medicine. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:278493. [PMID: 24876869 PMCID: PMC4021742 DOI: 10.1155/2014/278493] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 01/04/2014] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease is neurodegenerative disorder due to the accumulation of amyloid-β in the brain and causes dementia with ageing. Some researches indicate that the RXR agonist, Targretin, has also been used for treatment of Alzheimer's disease in mouse models. We investigate the potent candidates as RXR agonists from the vast repertoire of TCM compounds in TCM Database@Taiwan. The potential TCM compounds, β-lipoic acid and sulfanilic acid, had higher potent binding affinities than both 9-cis-retinoic acid and Targretin in docking simulation and have stable H-bonds with residues Arg316 and some equivalent hydrophobic contacts with residues Ala272, Gln275, Leu309, Phe313, Val342, Ile345, and Cys432 as Targretin. The carboxyl or sulfonyl hydroxide group can form a H-bond with key residue Arg316 in the docking pose, and the phenyl group next to the carboxyl or sulfonyl hydroxide group can form a π interaction with residue Phe313. Moreover, β-lipoic acid and sulfanilic acid have stable H-bonds with residue Gln275, Ser313, and residue Ala327, respectively, which may strengthen and stabilize TCM candidates inside the binding domain of RXR protein. Hence, we propose β-lipoic acid and sulfanilic acid as potential lead compounds for further study in drug development process with the RXR protein against Alzheimer's disease.
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Abstract
Retinoid X Receptors (RXR) were initially identified as nuclear receptors binding with stereo-selectivity the vitamin A derivative 9-cis retinoic acid, although the relevance of this molecule as endogenous activator of RXRs is still elusive. Importantly, within the nuclear receptor superfamily, RXRs occupy a peculiar place, as they are obligatory partners for a number of other nuclear receptors, thus integrating the corresponding signaling pathways. In this chapter, we describe the structural features allowing RXR to form homo- and heterodimers, and the functional consequences of this unique ability. Furthermore, we discuss the importance of studying RXR activity at a genome-wide level in order to comprehensively address the biological implications of their action that is fundamental to understand to what extent RXRs could be exploited as new therapeutic targets.
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Affiliation(s)
- Federica Gilardi
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne, Switzerland,
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Rastinejad F, Huang P, Chandra V, Khorasanizadeh S. Understanding nuclear receptor form and function using structural biology. J Mol Endocrinol 2013; 51:T1-T21. [PMID: 24103914 PMCID: PMC3871882 DOI: 10.1530/jme-13-0173] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nuclear receptors (NRs) are a major transcription factor family whose members selectively bind small-molecule lipophilic ligands and transduce those signals into specific changes in gene programs. For over two decades, structural biology efforts were focused exclusively on the individual ligand-binding domains (LBDs) or DNA-binding domains of NRs. These analyses revealed the basis for both ligand and DNA binding and also revealed receptor conformations representing both the activated and repressed states. Additionally, crystallographic studies explained how NR LBD surfaces recognize discrete portions of transcriptional coregulators. The many structural snapshots of LBDs have also guided the development of synthetic ligands with therapeutic potential. Yet, the exclusive structural focus on isolated NR domains has made it difficult to conceptualize how all the NR polypeptide segments are coordinated physically and functionally in the context of receptor quaternary architectures. Newly emerged crystal structures of the peroxisome proliferator-activated receptor-γ-retinoid X receptor α (PPARγ-RXRα) heterodimer and hepatocyte nuclear factor (HNF)-4α homodimer have recently revealed the higher order organizations of these receptor complexes on DNA, as well as the complexity and uniqueness of their domain-domain interfaces. These emerging structural advances promise to better explain how signals in one domain can be allosterically transmitted to distal receptor domains, also providing much better frameworks for guiding future drug discovery efforts.
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Affiliation(s)
- Fraydoon Rastinejad
- Metabolic Signaling and Disease Program, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, USA
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25
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Ignatovich IV, Hobbs JA. Human parvovirus B19 infection leads to downregulation of thyroid, estrogen, and retinoid hormone receptor expression. Virology 2013; 446:173-9. [DOI: 10.1016/j.virol.2013.06.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/31/2013] [Accepted: 06/24/2013] [Indexed: 01/15/2023]
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Nagy L, Szanto A, Szatmari I, Széles L. Nuclear hormone receptors enable macrophages and dendritic cells to sense their lipid environment and shape their immune response. Physiol Rev 2012; 92:739-89. [PMID: 22535896 DOI: 10.1152/physrev.00004.2011] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A key issue in the immune system is to generate specific cell types, often with opposing activities. The mechanisms of differentiation and subtype specification of immune cells such as macrophages and dendritic cells are critical to understand the regulatory principles and logic of the immune system. In addition to cytokines and pathogens, it is increasingly appreciated that lipid signaling also has a key role in differentiation and subtype specification. In this review we explore how intracellular lipid signaling via a set of transcription factors regulates cellular differentiation, subtype specification, and immune as well as metabolic homeostasis. We introduce macrophages and dendritic cells and then we focus on a group of transcription factors, nuclear receptors, which regulate gene expression upon receiving lipid signals. The receptors we cover are the ones with a recognized physiological function in these cell types and ones which heterodimerize with the retinoid X receptor. These are as follows: the receptor for a metabolite of vitamin A, retinoic acid: retinoic acid receptor (RAR), the vitamin D receptor (VDR), the fatty acid receptor: peroxisome proliferator-activated receptor γ (PPARγ), the oxysterol receptor liver X receptor (LXR), and their obligate heterodimeric partner, the retinoid X receptor (RXR). We discuss how they can get activated and how ligand is generated and eliminated in these cell types. We also explore how activation of a particular target gene contributes to biological functions and how the regulation of individual target genes adds up to the coordination of gene networks. It appears that RXR heterodimeric nuclear receptors provide these cells with a coordinated and interrelated network of transcriptional regulators for interpreting the lipid milieu and the metabolic changes to bring about gene expression changes leading to subtype and functional specification. We also show that these networks are implicated in various immune diseases and are amenable to therapeutic exploitation.
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Affiliation(s)
- Laszlo Nagy
- Department of Biochemistry and Molecular Biology, University of Debrecen, Medical and Health Science Center, Egyetem tér 1, Debrecen, Hungary.
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Thomas M, Sukhai MA, Kamel-Reid S. An emerging role for retinoid X receptor α in malignant hematopoiesis. Leuk Res 2012; 36:1075-81. [PMID: 22710246 DOI: 10.1016/j.leukres.2012.05.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 04/13/2012] [Accepted: 05/21/2012] [Indexed: 12/29/2022]
Abstract
The retinoid X receptor alpha is the obligatory heterodimerization partner for a range of nuclear hormone receptors, and is required for signaling through the pathways mediated by those receptors. While RXR alpha has critical roles in embryonic development, it appears to be dispensable in adult hematopoiesis. Strikingly, recent evidence has indicated that proper functioning of RXR alpha is necessary for the pathogenesis of acute promyelocytic leukemia (APL), suggesting a novel avenue that can be exploited in the management and treatment of this disease. In this review we highlight recent studies that clarify the role of RXR alpha in normal and malignant hematopoiesis.
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Affiliation(s)
- Mariam Thomas
- Princess Margaret Hospital/the Ontario Cancer Institute, University Health Network, Toronto, ON, Canada
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Bernardes A, Batista FAH, de Oliveira Neto M, Figueira ACM, Webb P, Saidemberg D, Palma MS, Polikarpov I. Low-resolution molecular models reveal the oligomeric state of the PPAR and the conformational organization of its domains in solution. PLoS One 2012; 7:e31852. [PMID: 22363753 PMCID: PMC3283691 DOI: 10.1371/journal.pone.0031852] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 01/17/2012] [Indexed: 01/02/2023] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) regulate genes involved in lipid and carbohydrate metabolism, and are targets of drugs approved for human use. Whereas the crystallographic structure of the complex of full length PPARγ and RXRα is known, structural alterations induced by heterodimer formation and DNA contacts are not well understood. Herein, we report a small-angle X-ray scattering analysis of the oligomeric state of hPPARγ alone and in the presence of retinoid X receptor (RXR). The results reveal that, in contrast with other studied nuclear receptors, which predominantly form dimers in solution, hPPARγ remains in the monomeric form by itself but forms heterodimers with hRXRα. The low-resolution models of hPPARγ/RXRα complexes predict significant changes in opening angle between heterodimerization partners (LBD) and extended and asymmetric shape of the dimer (LBD-DBD) as compared with X-ray structure of the full-length receptor bound to DNA. These differences between our SAXS models and the high-resolution crystallographic structure might suggest that there are different conformations of functional heterodimer complex in solution. Accordingly, hydrogen/deuterium exchange experiments reveal that the heterodimer binding to DNA promotes more compact and less solvent-accessible conformation of the receptor complex.
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Affiliation(s)
- Amanda Bernardes
- Institute of Physics of São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Fernanda A. H. Batista
- Institute of Physics of São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | - Mario de Oliveira Neto
- Institute of Physics of São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
| | | | - Paul Webb
- Diabetes Center and Cancer Research Unit, Methodist Hospital, Houston, Texas, United States of America
| | - Daniel Saidemberg
- Department of Biology, Center of Study of Social Insects (CEIS), Institute of Biosciences of Rio Claro, Universidade Estadual de São Paulo (UNESP), Rio Claro, São Paulo, Brazil,
- National Institute of Science and Technology on Immunology (INCT/iii), São Paulo, Brazil
| | - Mario S. Palma
- Department of Biology, Center of Study of Social Insects (CEIS), Institute of Biosciences of Rio Claro, Universidade Estadual de São Paulo (UNESP), Rio Claro, São Paulo, Brazil,
- National Institute of Science and Technology on Immunology (INCT/iii), São Paulo, Brazil
| | - Igor Polikarpov
- Institute of Physics of São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil
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Janakiram NB, Mohammed A, Qian L, Choi CI, Steele VE, Rao CV. Chemopreventive effects of RXR-selective rexinoid bexarotene on intestinal neoplasia of Apc(Min/+) mice. Neoplasia 2012; 14:159-68. [PMID: 22431924 PMCID: PMC3306261 DOI: 10.1593/neo.111440] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 01/30/2012] [Accepted: 02/03/2012] [Indexed: 12/18/2022]
Abstract
Retinoid X receptor (RXR) has been implicated in several neoplastic diseases. Previously, we have shown that RXR-α is downregulated in human and rodent colonic tumors, suggesting a potential target for colon cancer prevention (http://www.cancer.org/Cancer/ColonandRectumCancer/DetailedGuide/colorectal-cancer-key-statistics). Experiments were designed to assess the chemopreventive efficacy of the selective RXR agonist bexarotene for the suppression of intestinal tumorigenesis in Apc(Min/+) mice. Before the efficacy studies, we determined that the maximal tolerated dose in C57BL/6J mice was less than 400 ppm. For the efficacy study, 6-week-old male and female C57BL/6J-Apc(Min/+) mice (nine mice per group) were fed diets containing 0, 30, and 60 ppm of bexarotene or 200 ppm of bexarotene for 80 days before intestinal tumors were evaluated. Dietary administration of 30 and 60 ppm of bexarotene suppressed the intestinal polyp formation by 38% (P < .015) and 60% (P < .0001) in males, respectively, and by 8.5% and 37% (P < .007) in females, respectively. Also, significant inhibition (50%-100%) of colonic tumor formation was observed in both male and female mice with bexarotene treatment. Administration of 200 ppm of bexarotene showed significant suppression of tumor formation (66%, P < .0001); however, it had significant toxicity. Intestinal tumors of bexarotene-fed mice showed significantly reduced expression of proliferating cell nuclear antigen (60%, P < .0001), cyclin D1, and cyclooxygenase 2 and increased RXR-α messenger RNA and uptake of oleate (34%, P < .01). Also, bexarotene-fed mice showed dose-dependent suppression of serum triglycerides (25%-72%, P < .0001) and inflammatory cytokines.
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Affiliation(s)
- Naveena B Janakiram
- Center for Chemoprevention and Cancer Drug Development, Department of Medicine, Hem-Onc Section, PC Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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30
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Paquette MA, Dong H, Gagné R, Williams A, Malowany M, Wade MG, Yauk CL. Thyroid hormone-regulated gene expression in juvenile mouse liver: identification of thyroid response elements using microarray profiling and in silico analyses. BMC Genomics 2011; 12:634. [PMID: 22206413 PMCID: PMC3340398 DOI: 10.1186/1471-2164-12-634] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/29/2011] [Indexed: 01/26/2023] Open
Abstract
Background Disruption of thyroid hormone signalling can alter growth, development and energy metabolism. Thyroid hormones exert their effects through interactions with thyroid receptors that directly bind thyroid response elements and can alter transcriptional activity of target genes. The effects of short-term thyroid hormone perturbation on hepatic mRNA transcription in juvenile mice were evaluated, with the goal of identifying genes containing active thyroid response elements. Thyroid hormone disruption was induced from postnatal day 12 to 15 by adding goitrogens to dams' drinking water (hypothyroid). A subgroup of thyroid hormone-disrupted pups received intraperitoneal injections of replacement thyroid hormones four hours prior to sacrifice (replacement). An additional group received only thyroid hormones four hours prior to sacrifice (hyperthyroid). Hepatic mRNA was extracted and hybridized to Agilent mouse microarrays. Results Transcriptional profiling enabled the identification of 28 genes that appeared to be under direct thyroid hormone-regulation. The regulatory regions of the genome adjacent to these genes were examined for half-site sequences that resemble known thyroid response elements. A bioinformatics search identified 33 thyroid response elements in the promoter regions of 13 different genes thought to be directly regulated by thyroid hormones. Thyroid response elements found in the promoter regions of Tor1a, 2310003H01Rik, Hect3d and Slc25a45 were further validated by confirming that the thyroid receptor is associated with these sequences in vivo and that it can bind directly to these sequences in vitro. Three different arrangements of thyroid response elements were identified. Some of these thyroid response elements were located far up-stream (> 7 kb) of the transcription start site of the regulated gene. Conclusions Transcriptional profiling of thyroid hormone disrupted animals coupled with a novel bioinformatics search revealed new thyroid response elements associated with genes previously unknown to be responsive to thyroid hormone. The work provides insight into thyroid response element sequence motif characteristics.
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Affiliation(s)
- Martin A Paquette
- Environmental Health Sciences and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, Ottawa, Ontario K1A 0K9, Canada
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31
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Gross J, Angerstein M, Fuchs J, Stute K, Mazurek B. Expression analysis of prestin and selected transcription factors in newborn rats. Cell Mol Neurobiol 2011; 31:1089-101. [PMID: 21614551 DOI: 10.1007/s10571-011-9708-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 05/11/2011] [Indexed: 01/16/2023]
Abstract
Transcription factors (TFs) have a central role to play in regulating gene expression. To analyze the co-expression patterns of selected TFs with the motor protein prestin of the outer hair cells, we applied an real-time PCR approach combining several kinds of information: (i) expression changes during postnatal development, (ii) expression changes by exposure of organotypic cultures of the organ of Corti to factors which significantly affect prestin expression [thyroid hormone (T4), retinoic acid (RA), butyric acid (BA), increased KCl concentration] and (iii) changes along the apical-basal gradient. We found that the mRNA levels of the TF Brn-3c (Pou4f3), a member of the POU family, are significantly associated with the regulation of prestin during postnatal development and in cultures supplemented with T4 (0.5 μM), BA (0.5-2.0 mM), and high KCl (50 mM) concentration. The mRNA level of the constitutively active TF C/ebpb (CCAAT/enhancer binding protein beta) correlates positively with the prestin expression during postnatal development and in cultures exposed to T4 and RA (50-100 μM). The mRNA levels of the calcium-dependent TF CaRF correlates significantly with the prestin expression in cultures exposed to T4 and high KCl concentration. The observed coexpression patterns may suggest that the TFs Brn-3c, C/ebpb, and Carf contribute to regulating the expression of prestin under the investigated conditions.
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Affiliation(s)
- Johann Gross
- Molecular Biology Research Laboratory, Department of Otorhinolaryngology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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32
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Tomic-Canic M, Stojadinovic O, Lee B, Walsh R, Blumenberg M. Nexus between epidermolysis bullosa and transcriptional regulation by thyroid hormone in epidermal keratinocytes. Clin Transl Sci 2010; 1:45-9. [PMID: 20443817 DOI: 10.1111/j.1752-8062.2008.00015.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract Thyroid hormone, T3, through the interaction of its receptor with the recognition sequences in the DNA, regulates gene expression. This regulation includes the promoter activity of keratin genes. The receptor shares coregulators with other members of the nuclear receptor family, including RXR. Intending to define the transcriptional effects of thyroid hormones in keratinocytes, we used Affymetrix microarrays to comprehensively compare the genes expressed in T3-treated and untreated human epidermal keratinocytes. The transcriptomes were compared at 1, 4, 24, 48, and 72 hours. Surprisingly, T3 induced only 9 and suppressed 28 genes, much fewer than expected. Significantly, genes associated with epidermolysis bullosa, a set of inherited blistering skin diseases, were found statistically highly overrepresented among the suppressed genes. These genes include Integrin beta4, Plectin, Collagen XVII, MMP1, MMP3, and MMP14. The data imply that in keratinocytes T3 could suppresses the remodeling by, attachment to, and production of extracellular matrix. The results suggest that topical treatment with T3 may be effective for alleviation of symptoms in patients with epidermolysis bullosa.
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Affiliation(s)
- Marjana Tomic-Canic
- The Departments of Dermatology and Biochemistry, and the NYU Cancer Institute, New York University School of Medicine, 550 First Avenue, New York, New York, USA
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33
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Kerrigan JJ, Xie Q, Ames RS, Lu Q. Production of protein complexes via co-expression. Protein Expr Purif 2010; 75:1-14. [PMID: 20692346 DOI: 10.1016/j.pep.2010.07.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/22/2010] [Accepted: 07/31/2010] [Indexed: 12/21/2022]
Abstract
Multi-protein complexes are involved in essentially all cellular processes. A protein's function is defined by a combination of its own properties, its interacting partners, and the stoichiometry of each. Depending on binding partners, a transcription factor can function as an activator in one instance and a repressor in another. The study of protein function or malfunction is best performed in the relevant context. While many protein complexes can be reconstituted from individual component proteins after being produced individually, many others require co-expression of their native partners in the host cells for proper folding, stability, and activity. Protein co-expression has led to the production of a variety of biological active complexes in sufficient quantities for biochemical, biophysical, structural studies, and high throughput screens. This article summarizes examples of such cases and discusses critical considerations in selecting co-expression partners, and strategies to achieve successful production of protein complexes.
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Affiliation(s)
- John J Kerrigan
- Biological Reagents & Assay Development, Platform Technology & Science, GlaxoSmithKline R&D, 1250 South Collegeville Road, Collegeville, PA 19426, USA
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34
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Mankame TP, Zhou G, Lingen MW. Identification and characterization of the human NOL7 gene promoter. Gene 2010; 456:36-44. [PMID: 20206243 PMCID: PMC3408873 DOI: 10.1016/j.gene.2010.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 01/29/2010] [Accepted: 02/16/2010] [Indexed: 11/24/2022]
Abstract
NOL7 is a candidate tumor suppressor gene that localizes to 6p23, a chromosomal region frequently associated with loss of heterozygosity in a number of malignancies including cervical cancer (CC). Re-expression of NOL7 in CC cells suppresses in vivo tumor growth by 95% and alters the angiogenic phenotype by modulating the expression of VEGF and TSP1. Here, we describe the determination of two NOL7 transcriptional start sites (TSS), the cloning of its regulatory promoter region, and the identification of transcription factors that regulate its expression. Using 5' Rapid amplification of complementary DNA ends (RACE), two transcriptional start sites were identified. Deletion analysis determined that the essential elements required for the optimal promoter activity of NOL7 were 560 bp upstream of its translation start site. In silico analysis suggested that the promoter region contained potential binding sites for the SP1, c-Myc and RXRalpha transcription factors as well as an overall GC content of greater than 60%. Chromatin immunoprecipitation (ChIP) confirmed that SP1, c-Myc and RXRalpha bound to the NOL7 promoter region. Finally, we demonstrate that NOL7 expression was positively regulated by c-Myc and RXRalpha. These results demonstrate that the NOL7 promoter region possesses each of the key elements of a TATA-less promoter. In addition, the positive regulation of NOL7 by c-Myc and RXRalpha provides additional mechanistic insights into the potential role of NOL7 in CC and other malignancies.
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Affiliation(s)
- Tanmayi P Mankame
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA
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35
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Pyper SR, Viswakarma N, Yu S, Reddy JK. PPARalpha: energy combustion, hypolipidemia, inflammation and cancer. NUCLEAR RECEPTOR SIGNALING 2010; 8:e002. [PMID: 20414453 PMCID: PMC2858266 DOI: 10.1621/nrs.08002] [Citation(s) in RCA: 291] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 03/04/2010] [Indexed: 12/11/2022]
Abstract
The peroxisome proliferator-activated receptor alpha (PPARalpha, or NR1C1) is a nuclear hormone receptor activated by a structurally diverse array of synthetic chemicals known as peroxisome proliferators. Endogenous activation of PPARalpha in liver has also been observed in certain gene knockout mouse models of lipid metabolism, implying the existence of enzymes that either generate (synthesize) or degrade endogenous PPARalpha agonists. For example, substrates involved in fatty acid oxidation can function as PPARalpha ligands. PPARalpha serves as a xenobiotic and lipid sensor to regulate energy combustion, hepatic steatosis, lipoprotein synthesis, inflammation and liver cancer. Mainly, PPARalpha modulates the activities of all three fatty acid oxidation systems, namely mitochondrial and peroxisomal beta-oxidation and microsomal omega-oxidation, and thus plays a key role in energy expenditure. Sustained activation of PPARalpha by either exogenous or endogenous agonists leads to the development of hepatocellular carcinoma resulting from sustained oxidative and possibly endoplasmic reticulum stress and liver cell proliferation. PPARalpha requires transcription coactivator PPAR-binding protein (PBP)/mediator subunit 1(MED1) for its transcriptional activity.
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Affiliation(s)
| | | | | | - Janardan K. Reddy
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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36
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Figueira ACM, Lima LMTR, Lima LHF, Ranzani AT, Mule GDS, Polikarpov I. Recognition by the thyroid hormone receptor of canonical DNA response elements. Biochemistry 2010; 49:893-904. [PMID: 20025240 DOI: 10.1021/bi901282s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To shed more light on the molecular requirements for recognition of thyroid response elements (TREs) by thyroid receptors (TRs), we compared the specific aspects of DNA TRE recognition by different TR constructs. Using fluorescence anisotropy, we performed a detailed and hierarchical study of TR-TRE binding. This was done by comparing the binding affinities of three different TR constructs for four different TRE DNA elements, including palindromic sequences and direct repeats (F2, PAL, DR-1, and DR-4) as well as their interactions with nonspecific DNA sequences. The effect of MgCl(2) on suppressing of nonselective DNA binding to TR was also investigated. Furthermore, we determined the dissociation constants of the hTRbeta DBD (DNA binding domain) and hTRbeta DBD-LBD (DNA binding and ligand binding domains) for specific TREs. We found that a minimum DNA recognition peptide derived from DBD (H1TR) is sufficient for recognition and interaction with TREs, whereas scrambled DNA sequences were unrecognized. Additionally, we determined that the TR DBD binds to F2, PAL, and DR-4 with high affinity and similar K(d) values. The TR DBD-LBD recognizes all the tested TREs but binds preferentially to F2, with even higher affinity. Finally, our results demonstrate the important role played by LBDs in modulating TR-DNA binding.
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Affiliation(s)
- Ana Carolina Migliorini Figueira
- Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Saocarlense, 400, Sao Carlos, SP, Brazil 13560-970
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37
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Rid R, Onder K, Trost A, Bauer J, Hintner H, Ritter M, Jakab M, Costa I, Reischl W, Richter K, MacDonald S, Jendrach M, Bereiter-Hahn J, Breitenbach M. H2O2-dependent translocation of TCTP into the nucleus enables its interaction with VDR in human keratinocytes: TCTP as a further module in calcitriol signalling. J Steroid Biochem Mol Biol 2010; 118:29-40. [PMID: 19815065 DOI: 10.1016/j.jsbmb.2009.09.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 09/27/2009] [Accepted: 09/29/2009] [Indexed: 01/07/2023]
Abstract
Translationally controlled tumour protein (TCTP) is an evolutionarily highly conserved molecule implicated in many processes related to cell cycle progression, proliferation and growth, to the protection against harmful conditions including apoptosis and to the human allergic response. We are showing here that after application of mild oxidative stress, human TCTP relocates from the cytoplasm to the nuclei of HaCaT keratinocytes where it directly associates with the ligand-binding domain of endogenous vitamin D(3) receptor (VDR) through its helical domain 2 (AA 71-132). Interestingly, the latter harbours a putative nuclear hormone receptor coregulatory LxxLL-like motif which seems to be involved in the interaction. Moreover, we demonstrate that VDR transcriptionally induces the expression of TCTP by binding to a previously unknown VDR response element within the TCTP promotor. Conversely, ectopically overexpressed TCTP downregulates the amount of VDR on both mRNA as well as protein level. These data, to conclude, suggest a kind of feedback regulation between TCTP and VDR to regulate a variety of (Ca(2+) dependent) cellular effects and in this way further underscore the physiological relevance of this novel protein-protein interaction.
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MESH Headings
- Active Transport, Cell Nucleus/drug effects
- Active Transport, Cell Nucleus/physiology
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Calcitriol/pharmacology
- Calcitriol/physiology
- Cell Line, Transformed
- Cell Nucleus/metabolism
- Cytoplasm/metabolism
- DNA/metabolism
- Electrophoretic Mobility Shift Assay
- Feedback, Physiological/physiology
- Fluorescence Resonance Energy Transfer
- Gene Expression/genetics
- Gene Expression Regulation, Neoplastic/physiology
- Humans
- Hydrogen Peroxide/pharmacology
- Immunoprecipitation
- Keratinocytes/drug effects
- Keratinocytes/metabolism
- Oxidative Stress/drug effects
- Oxidative Stress/physiology
- Promoter Regions, Genetic/genetics
- Protein Binding/drug effects
- Protein Binding/physiology
- Protein Interaction Domains and Motifs/physiology
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Recombinant Proteins/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Tumor Protein, Translationally-Controlled 1
- Two-Hybrid System Techniques
- Vitamin D Response Element/genetics
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Affiliation(s)
- Raphaela Rid
- Department of Cell Biology, Division of Genetics, University of Salzburg, Salzburg, Austria
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38
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Volate SR, Muga SJ, Issa AY, Nitcheva D, Smith T, Wargovich MJ. Epigenetic modulation of the retinoid X receptor alpha by green tea in the azoxymethane-Apc Min/+ mouse model of intestinal cancer. Mol Carcinog 2009; 48:920-33. [PMID: 19378291 DOI: 10.1002/mc.20542] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We investigated the possible mechanisms of inhibition of colorectal carcinogenesis by green tea (GT) in azoxymethane-treated (AOM) Apc(Min/+) mice. Mice received water or a 0.6% (w/v) solution of GT as the only source of beverage. GT treatment commenced at the 8th week of age and lasted for 8 wk. The treatment caused a statistically significant reduction in the number of newly formed tumors (28%, P < 0.05). Immunohistochemical analysis showed that GT decreased the levels of beta-catenin and its downstream target cyclin D1. To probe a mechanism, we further investigated the expression of retinoic X receptor alpha (RXR alpha) in AOM/Apc(Min/+) tumors. Our results show that RXR alpha is selectively downregulated in AOM/Apc(Min/+) mouse intestinal tumors. In contrast, other retinoic receptors including retinoic acid receptor alpha (RAR alpha), RAR beta, RXR beta, and RXR gamma were all expressed in Apc(Min/+) adenomas. Furthermore, our results show that RXR alpha downregulation is an early event in colorectal carcinogenesis and is independent of beta-catenin expression. GT significantly increased the protein levels of RXR alpha. In addition, RT-PCR analysis showed that GT induced a similar increase in the levels of RXR alpha mRNA. Genomic bisulfite treatment of colonic DNA followed by pyrosequencing of 24 CpG sites in the promoter region of RXR alpha gene showed a significant decrease in CpG methylation with GT treatment. The results suggest that a low concentration of GT is sufficient to desilence RXR alpha and inhibit intestinal tumorigenesis in the Apc(Min/+) mouse.
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Affiliation(s)
- Suresh R Volate
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, South Carolina, USA
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39
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40
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Evidence of functional interaction between NuMA-RARα and RXRα in an in vivo model of acute promyelocytic leukemia. Oncogene 2008; 27:4666-77. [DOI: 10.1038/onc.2008.106] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Boehm MF, Heyman RA, Patel S, Stein RB, Nagpal S. Section Review: Retinoids: Biological Function and Use in the Treatment of Dermatological Diseases: Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.4.7.593] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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42
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Takayama S, Hostick U, Haendel M, Eisen J, Darimont B. An F-domain introduced by alternative splicing regulates activity of the zebrafish thyroid hormone receptor alpha. Gen Comp Endocrinol 2008; 155:176-89. [PMID: 17583703 PMCID: PMC3758257 DOI: 10.1016/j.ygcen.2007.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 03/19/2007] [Accepted: 04/13/2007] [Indexed: 11/15/2022]
Abstract
Thyroid hormones (THs) play an important role in vertebrate development; however, the underlying mechanisms of their actions are still poorly understood. Zebrafish (Danio rerio) is an emerging vertebrate model system to study the roles of THs during development. In general, the response to THs relies on closely related proteins and mechanisms across vertebrate species, however some species-specific differences exist. In contrast to mammals, zebrafish has two TRalpha genes (thraa, thrab). Moreover, the zebrafish thraa gene expresses a TRalpha isoform (TRalphaA1) that differs from other TRs by containing additional C-terminal amino acids. C-terminal extensions, called "F domains", are common in other members of the nuclear receptor superfamily and modulate the response of these receptors to hormones. Here we demonstrate that the F-domain constrains the transcriptional activity of zebrafish TRalpha by altering the selectivity of this receptor for certain coactivator binding motifs. We found that the F-domain of zebrafish TRalphaA1 is encoded on a separate exon whose inclusion is regulated by alternative splicing, indicating a regulatory role of the F-domain in vivo. Quantitative expression analyses revealed that TRalphaA1 is primarily expressed in reproductive organs whereas TRalphaB and the TRalphaA isoform that lacks the F-domain (TRalphaA1-2) appear to be ubiquitous. The relative expression levels of these TRalpha transcripts differ in a tissue-specific manner suggesting that zebrafish uses both alternative splicing and differential expression of TRalpha genes to diversify the cellular response to THs.
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Affiliation(s)
- Sachiko Takayama
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Ute Hostick
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Melissa Haendel
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Judith Eisen
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Beatrice Darimont
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
- Corresponding author: Institute of Molecular Biology University of Oregon Eugene, OR, 97403-1229 Phone: (541) 346-5265 Fax: (541) 346-5891
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43
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Jugan ML, Lévy-Bimbot M, Pomérance M, Tamisier-Karolak S, Blondeau JP, Lévi Y. A new bioluminescent cellular assay to measure the transcriptional effects of chemicals that modulate the alpha-1 thyroid hormone receptor. Toxicol In Vitro 2007; 21:1197-205. [PMID: 17532181 DOI: 10.1016/j.tiv.2007.03.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 03/26/2007] [Accepted: 03/28/2007] [Indexed: 10/23/2022]
Abstract
Interactions of environmental pollutants with the thyroid endocrine axis have received much attention especially because thyroid hormones (THs) play a major role in mammalian brain development. In order to screen for compounds that act on the triiodothyronine (T3) signaling pathway, we developed a new reporter gene assay expressing luciferase under the control of the TH receptor (TR). PC12 cells expressing the alpha1-isoform of TR of avian origin were stably transfected with a luciferase gene controlled by the SV40 promoter, and enhanced by a four-spaced direct repeat (DR4) thyroid response element (TRE). The resulting PC-DR-LUC cells were used to optimize a T3 assay in multiwell microplates. This assay was highly sensitive (30 pM T3) and reproducible, and responded as expected to TH analogues. Several halogenated phenolic (3,3',5,5'-tetrabromobisphenol A, 3,3',5,5'-tetrachlorobisphenol A, 4-hydroxy-2',3,4',5,6'-pentachlorobiphenyl) and phenol (pentachlorophenol, 2,4,6-triiodophenol) compounds suspected of being thyroid-disrupting environmental chemicals induced partial agonistic and/or complex competitive/uncompetitive antagonistic responses in PC-DR-LUC cells at micromolar concentrations. A cell viability test indicated that these effects were not related to cytotoxicity of the chemicals. These results suggest that the PC-DR-LUC assay could be a valuable tool for the large-scale screening for thyroid receptor agonists and antagonists in vitro, and for detecting thyroid disruptors in the environment.
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Affiliation(s)
- M L Jugan
- Univ Paris-Sud, Faculté de Pharmacie, Laboratoire Santé Publique-Environnement, F-92296 Châtenay-Malabry, France
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44
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Niles RM. Biomarker and animal models for assessment of retinoid efficacy in cancer chemoprevention. Acta Pharmacol Sin 2007; 28:1383-91. [PMID: 17723172 DOI: 10.1111/j.1745-7254.2007.00685.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Vitamin A is essential for normal growth and development. Epidemiology and laboratory studies suggest that decreased vitamin A levels and defective metabolism/ action may contribute to the genesis of certain cancers. Based on this information, natural and synthetic derivatives of vitamin A (retinoids) have been used for chemoprevention of cancer. Retinoids have had some success in the chemoprevention of leukoplakia and in the decreased incidence of second primaries in head and neck cancer. There is little information on biomarkers that can be used to assess the efficacy of the chemopreventive activity of retinoids. The ability of retinoids to induce RARb has been consistently shown to correlate with the response of cells and tissues to retinoic acid, but few other biomarkers have been certified as indicators of retinoid activity. In light of the failure of the ATBC and CARET clinical intervention trials for chemoprevention of lung cancer, greater use of animal models for chemoprevention studies is necessary. The potential combination of phytochemicals that inhibit DNA methyltransferase activity with retinoids holds promise for more effective chemoprevention of retinoid-unresponsive premalignant lesions.
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Affiliation(s)
- Richard M Niles
- Department of Biochemistry and Microbiology, Joan C Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA.
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45
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Germain P, Chambon P, Eichele G, Evans RM, Lazar MA, Leid M, De Lera AR, Lotan R, Mangelsdorf DJ, Gronemeyer H. International Union of Pharmacology. LXIII. Retinoid X receptors. Pharmacol Rev 2007; 58:760-72. [PMID: 17132853 DOI: 10.1124/pr.58.4.7] [Citation(s) in RCA: 376] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The physiological effects of retinoic acids (RAs) are mediated by members of two families of nuclear receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs), which are encoded by three distinct human genes, RXRalpha, RXRbeta, and RXRgamma. RARs bind both all-trans- and 9-cis-RA, whereas only the 9-cis-RA stereoisomer binds to RXRs. As RXR/RAR heterodimers, these receptors control the transcription of RA target genes through binding to RA-response elements. This review is focused on the structure, mode of action, ligands, expression, and pharmacology of RXRs. Given their role as common partners to many other members of the nuclear receptor superfamily, these receptors have been the subject of intense scrutiny. Moreover, and despite numerous studies since their initial discovery, RXRs remain enigmatic nuclear receptors, and there is still no consensus regarding their role. Indeed, multiple questions about the actual biological role of RXRs and the existence of an endogenous ligand have still to be answered.
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Affiliation(s)
- Pierre Germain
- Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur, Illkirch, Communauté Urbaine de Strasbourg, France.
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Abstract
The retinas of teleost fish have long been of interest to developmental neurobiologists for their persistent plasticity during growth, life history changes, and response to injury. Because the vertebrate retina is a highly conserved tissue, the study of persistent plasticity in teleosts has provided insights into mechanisms for postembryonic retinal neurogenesis in mammals. In addition, in the past 10 years there has been an explosion in the use of teleost fish-zebrafish (Danio rerio) in particular-to understand the mechanisms of embryonic retinal neurogenesis in a model vertebrate with genetic resources. This review summarizes the key features of teleost retinal neurogenesis that make it a productive and interesting experimental system, and focuses on the contributions to our knowledge of retinal neurogenesis that uniquely required or significantly benefited from the use of a fish model system.
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Affiliation(s)
- Deborah L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844, USA
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Shimizu T, Esaki L, Mizuno H, Takeda K. Granulocyte macrophage colony-stimulating factor enhances retinoic acid-induced gene expression. J Leukoc Biol 2006; 80:889-96. [PMID: 16885501 DOI: 10.1189/jlb.0905502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We reported previously that treatment of human myeloblastic leukemia ML-1 cells with all-trans retinoic acid (ATRA) in combination with GM-CSF enhances the granulocytic differentiation, which is induced only slightly by ATRA alone. To investigate the mechanism underlying this differentiation and the synergistic effect of ATRA and GM-CSF, we used cDNA microarray to examine gene expression profiles of ML-1 cells treated with ATRA and/or GM-CSF. We identified 22 up-regulated genes in ML-1 cells treated with both reagents and examined the expression of these genes in cells treated with ATRA and/or GM-CSF by Northern blot analysis. Comparison of cells treated with both reagents and cells treated with ATRA or GM-CSF alone revealed that expression of nine of the 19 genes was induced synergistically by combined treatment with ATRA and GM-CSF. Expression of most of these genes was increased only slightly by ATRA alone, and this induction was enhanced by the addition of GM-CSF. These results indicate that GM-CSF enhances ATRA-induced gene expression. Moreover, studies with inhibitors of signaling molecules suggested that activation of JAK2 is associated with the synergistic induction of several genes by ATRA and GM-CSF. JAK2 inhibitor suppressed induction of NBT-reducing activity in ML-1 cells treated with both reagents. It is likely that the enhancer effect of GM-CSF on ATRA-induced gene expression leads to the differentiation induced synergistically by ATRA combined with GM-CSF. Further studies of the mechanism underlying this effect may identify better approaches for the treatment of RA-insensitive leukemia.
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Affiliation(s)
- Takahisa Shimizu
- Department of Hygiene-Chemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba 278-8510, Japan.
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Schwabe JW, Chapman L, Finch JT, Rhodes D, Neuhaus D. DNA recognition by the oestrogen receptor: from solution to the crystal. Structure 2005; 1:187-204. [PMID: 16100953 DOI: 10.1016/0969-2126(93)90020-h] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The steroid/nuclear hormone receptors are a large family of conserved ligand-activated transcription factors that regulate gene expression through binding to response elements upstream of their target genes. Most members of this family bind to DNA as homodimers or heterodimers and recognize the sequence, spacing and orientation of the two half-sites of their response elements. The recognition and discrimination of the sequence and arrangements of these half-sites are mediated primarily by a highly conserved DNA-binding domain. RESULTS Here we describe the DNA-binding properties of the isolated DNA-binding domain of the oestrogen receptor, the ERDBD, and its refined NMR structure. This domain is monomeric in solution, but two molecules bind cooperatively to specific DNA sequences; this cooperativity determines the arrangement of half-sites that is recognized by the ERDBD. The 10 carboxy-terminal residues and a region of 15 residues within the domain are disordered in the solution structure, yet are important for DNA binding. CONCLUSION The cooperative nature of ERDBD binding to DNA is important. The previously-determined X-ray structure of the ERDBD dimer bound to DNA shows that the 15 internal residues disordered in solution make contact both with DNA and with the corresponding region of the other monomer. These results suggest that these residues become ordered during the process of binding to DNA, forming the dimer interface and thus contributing to the cooperative interaction between monomers.
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Affiliation(s)
- J W Schwabe
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 2QH, UK
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Lefebvre P, Martin PJ, Flajollet S, Dedieu S, Billaut X, Lefebvre B. Transcriptional activities of retinoic acid receptors. VITAMINS AND HORMONES 2005; 70:199-264. [PMID: 15727806 DOI: 10.1016/s0083-6729(05)70007-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin A derivatives plays a crucial role in embryonic development, as demonstrated by the teratogenic effect of either an excess or a deficiency in vitamin A. Retinoid effects extend however beyond embryonic development, and tissue homeostasis, lipid metabolism, cellular differentiation and proliferation are in part controlled through the retinoid signaling pathway. Retinoids are also therapeutically effective in the treatment of skin diseases (acne, psoriasis and photoaging) and of some cancers. Most of these effects are the consequences of retinoic acid receptors activation, which triggers transcriptional events leading either to transcriptional activation or repression of retinoid-controlled genes. Synthetic molecules are able to mimic part of the biological effects of the natural retinoic acid receptors, all-trans retinoic acid. Therefore, retinoic acid receptors are considered as highly valuable therapeutic targets and limiting unwanted secondary effects due to retinoid treatment requires a molecular knowledge of retinoic acid receptors biology. In this review, we will examine experimental evidence which provide a molecular basis for the pleiotropic effects of retinoids, and emphasize the crucial roles of coregulators of retinoic acid receptors, providing a conceptual framework to identify novel therapeutic targets.
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Affiliation(s)
- Philippe Lefebvre
- INSERM U459 and Ligue Nationale Contre le Cancer, Faculté de Médecine de Lille, 59045 Lille cedex, France
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Szanto A, Narkar V, Shen Q, Uray IP, Davies PJA, Nagy L. Retinoid X receptors: X-ploring their (patho)physiological functions. Cell Death Differ 2005; 11 Suppl 2:S126-43. [PMID: 15608692 DOI: 10.1038/sj.cdd.4401533] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Retinoid X receptor (RXR) belongs to a family of ligand-activated transcription factors that regulate many aspects of metazoan life. A class of nuclear receptors requires RXR as heterodimerization partner for their function. This places RXR in the crossroad of multiple distinct biological pathways. This and the fact that the debate on the endogenous ligand requirement for RXR is not yet settled make RXR still an enigmatic transcription factor. Here, we review some of the biology of RXR. We place RXR into the evolution of nuclear receptors, review structural details and ligands of the receptor. Then processes regulated by RXR are discussed focusing on the developmental roles deduced from studies on knockout animals and metabolic roles in diseases such as diabetes and atherosclerosis deduced from pharmacological studies. Finally, aspects of RXR's involvement in myeloid differentiation and apoptosis are summarized along with issues on RXR's suitability as a therapeutic target.
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Affiliation(s)
- A Szanto
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Nagyerdei krt. 98, Debrecen H-4012, Hungary
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