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Rani A. RAR-related orphan receptor alpha and the staggerer mice: a fine molecular story. Front Endocrinol (Lausanne) 2024; 14:1300729. [PMID: 38766309 PMCID: PMC11099308 DOI: 10.3389/fendo.2023.1300729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 12/15/2023] [Indexed: 05/22/2024] Open
Abstract
The retinoic acid-related orphan receptor alpha (RORα) protein first came into the limelight due to a set of staggerer mice, discovered at the Jackson Laboratories in the United States of America by Sidman, Lane, and Dickie (1962) and genetically deciphered by Hamilton et al. in 1996. These staggerer mice exhibited cerebellar defects, an ataxic gait, a stagger along with several other developmental abnormalities, compensatory mechanisms, and, most importantly, a deletion of 160 kilobases (kb), encompassing the RORα ligand binding domain (LBD). The discovery of the staggerer mice and the subsequent discovery of a loss of the LBD within the RORα gene of these mice at the genetic level clearly indicated that RORα's LBD played a crucial role in patterning during embryogenesis. Moreover, a chance study by Roffler-Tarlov and Sidman (1978) noted reduced concentrations of glutamic acid levels in the staggerer mice, indicating a possible role for the essence of a nutritionally balanced diet. The sequential organisation of the building blocks of intact genes, requires the nucleotide bases of deoxyribonucleic acid (DNA): purines and pyrimidines, both of which are synthesized, upon a constant supply of glutamine, an amino acid fortified in a balanced diet and a byproduct of the carbohydrate and lipid metabolic pathways. A nutritionally balanced diet, along with a metabolic "enzymatic machinery" devoid of mutations/aberrations, was essential in the uninterrupted transcription of RORα during embryogenesis. In addition to the above, following translation, a ligand-responsive RORα acts as a "molecular circadian regulator" during embryogenesis and not only is expressed selectively and differentially, but also promotes differential activity depending on the anatomical and pathological site of its expression. RORα is highly expressed in the central nervous system (CNS) and the endocrine organs. Additionally, RORα and the clock genes are core components of the circadian rhythmicity, with the expression of RORα fluctuating in a night-day-night sigmoidal pattern and undoubtedly serves as an endocrine-like, albeit "molecular-circadian regulator". Melatonin, a circadian hormone, along with tri-iodothyronine and some steroid hormones are known to regulate RORα-mediated molecular activity, with each of these hormones themselves being regulated rhythmically by the hypothalamic-pituitary axis (HPA). The HPA regulates the circadian rhythm and cyclical release of hormones, in a self-regulatory feedback loop. Irregular sleep-wake patterns affect circadian rhythmicity and the ability of the immune system to withstand infections. The staggerer mice with their thinner bones, an altered skeletal musculature, an aberrant metabolic profile, the ataxic gait and an underdeveloped cerebellar cortex; exhibited compensatory mechanisms, that not only allowed the survival of the staggerer mice, but also enhanced protection from microbial invasions and resistance to high-fat-diet induced obesity. This review has been compiled in its present form, more than 14 years later after a chromatin immunoprecipitation (ChIP) cloning and sequencing methodology helped me identify signal transducer and activator of transcription 5 (STAT5) target sequences, one of which was mapped to the first intron of the RORα gene. The 599-base-long sequence containing one consensus TTCNNNGAA (TTCN3GAA) gamma-activated sequence (GAS) and five other non-consensus TTN5AA sequences had been identified from the clones isolated from the STAT5 target sites (fragments) in human phytohemagglutinin-activated CD8+ T lymphocytes, during my doctoral studies between 2006 and 2009. Most importantly, preliminary studies noted a unique RORα expression profile, during a time-course study on the ribonucleic acid (RNA), extracted from human phytohemagglutinin (PHA) activated CD8+ T lymphocytes stimulated with interleukin-2 (IL-2). This review mainly focuses on the "staggerer mice" with one of its first roles materialising during embryogenesis, a molecular-endocrine mediated circadian-like regulatory process.
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Affiliation(s)
- Aradhana Rani
- Medical Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India
- Human Resource Development and Management, Indian Institute of Technology (IIT) Kharagpur, West Bengal, India
- Immunology, King’s College London, London, United Kingdom
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2
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Jiang L, Liu X, Liang X, Dai S, Wei H, Guo M, Chen Z, Xiao D, Chen Y. Structural characterization of the DNA binding mechanism of retinoic acid-related orphan receptor gamma. Structure 2024; 32:467-475.e3. [PMID: 38309263 DOI: 10.1016/j.str.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/15/2023] [Accepted: 01/08/2024] [Indexed: 02/05/2024]
Abstract
Retinoic acid-related orphan receptor gamma (RORγ) plays critical roles in regulating various biological processes and has been linked to immunodeficiency disorders and cancers. DNA recognition is essential for RORγ to exert its functions. However, the underlying mechanism of the DNA binding by RORγ remains unclear. In this study, we present the crystal structure of the complex of RORγ1 DNA-binding domain (RORγ1-DBD)/direct repeat DNA element DR2 at 2.3 Å resolution. We demonstrate that RORγ1-DBD binds the DR2 motif as a homodimer, with the C-terminal extension (CTE) region of RORγ1-DBD contributing to the DNA recognition and the formation of dimeric interface. Further studies reveal that REV-ERB-DBD and RXR-DBD, also bind the DR2 site as a homodimer, while NR4A2-DBD binds DR2 as a monomer. Our research uncovers a binding mechanism of RORγ1 to the DR2 site and provides insights into the biological functions of RORγ1 and the broader RORs subfamily.
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Affiliation(s)
- Longying Jiang
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xueke Liu
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xujun Liang
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shuyan Dai
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hudie Wei
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ming Guo
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhuchu Chen
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Desheng Xiao
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China.
| | - Yongheng Chen
- Department of Pathology, NHC Key Laboratory of Cancer Proteomics, State Local Joint Engineering Laboratory for Anticancer Drugs, Department of Oncology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China.
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3
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Pastwińska J, Karwaciak I, Karaś K, Bachorz RA, Ratajewski M. RORγT agonists as immune modulators in anticancer therapy. Biochim Biophys Acta Rev Cancer 2023; 1878:189021. [PMID: 37951483 DOI: 10.1016/j.bbcan.2023.189021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/26/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023]
Abstract
RORγT is a transcription factor that directs the development of Th17 lymphocytes and other IL-17-expressing cells (e.g., Tc17 and ILC3 cells). These cells are involved in the body's defense against pathogenic bacteria and fungi, but they also participate in maintaining the proinflammatory environment in some autoimmune diseases and play a role in the immune system's response to cancer. Similar to other members of the nuclear receptor superfamily, the activity of RORγT is regulated by low-molecular-weight ligands. Therefore, extensive efforts have been dedicated to identifying inverse agonists that diminish the activity of this receptor and subsequently inhibit the development of autoimmune diseases. Unfortunately, in the pursuit of an ideal inverse agonist, the development of agonists has been overlooked. It is important to remember that these types of compounds, by stimulating lymphocytes expressing RORγT (Th17 and Tc17), can enhance the immune system's response to tumors. In this review, we present recent advancements in the biology of RORγT agonists and their potential application in anticancer therapy.
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Affiliation(s)
- Joanna Pastwińska
- Laboratory of Epigenetics, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232 Lodz, Poland
| | - Iwona Karwaciak
- Laboratory of Epigenetics, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232 Lodz, Poland
| | - Kaja Karaś
- Laboratory of Epigenetics, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232 Lodz, Poland
| | - Rafał A Bachorz
- Laboratory of Molecular Modeling, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232 Lodz, Poland
| | - Marcin Ratajewski
- Laboratory of Epigenetics, Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232 Lodz, Poland.
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4
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Pitsillou E, Liang JJ, Beh RC, Hung A, Karagiannis TC. Identification of dietary compounds that interact with the circadian clock machinery: Molecular docking and structural similarity analysis. J Mol Graph Model 2023; 123:108529. [PMID: 37263157 DOI: 10.1016/j.jmgm.2023.108529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/11/2023] [Accepted: 05/21/2023] [Indexed: 06/03/2023]
Abstract
The molecular clock is vital for regulating circadian rhythms in various physiological processes, and its dysregulation is associated with multiple diseases. As such, the use of small molecule modulators to regulate the molecular clock presents a promising therapeutic approach. In this study, we generated a homology model of the human circadian locomotor output cycles kaput (CLOCK) protein to evaluate its ligand binding sites. Using molecular docking, we obtained further insights into the binding mode of the control compound CLK8 and explored a selection of dietary compounds. Our investigation of dietary compounds was guided by their potential interactions with the retinoic acid-related orphan receptors RORα/γ, which are involved in circadian regulation. Through the molecular similarity and docking analyses, we identified oleanolic acid demethyl, 3-epi-lupeol, and taraxasterol as potential ROR-interacting compounds. These compounds may exert therapeutic effects through their modulation of RORα/γ activity and subsequently influence the molecular clock. Overall, our study highlights the potential of small molecule modulators in regulating the molecular clock and the importance of exploring dietary compounds as a source of such modulators. Our findings also provide insights into the binding mechanisms of CLK8 and shed light on potential compounds that can interact with RORs to regulate the molecular clock. Future investigations could focus on validating the efficacy of these compounds in modulating the molecular clock and their potential use as therapeutic agents.
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Affiliation(s)
- Eleni Pitsillou
- Epigenomic Medicine Laboratory at ProspED, Carlton, VIC, 3053, Australia; School of Science, STEM College, RMIT University, VIC, 3001, Australia
| | - Julia J Liang
- Epigenomic Medicine Laboratory at ProspED, Carlton, VIC, 3053, Australia; School of Science, STEM College, RMIT University, VIC, 3001, Australia
| | - Raymond C Beh
- Epigenomic Medicine Laboratory at ProspED, Carlton, VIC, 3053, Australia; School of Science, STEM College, RMIT University, VIC, 3001, Australia
| | - Andrew Hung
- School of Science, STEM College, RMIT University, VIC, 3001, Australia
| | - Tom C Karagiannis
- Epigenomic Medicine Laboratory at ProspED, Carlton, VIC, 3053, Australia; Department of Clinical Pathology, The University of Melbourne, Parkville, VIC, 3010, Australia.
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5
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Hall JA, Pokrovskii M, Kroehling L, Kim BR, Kim SY, Wu L, Lee JY, Littman DR. Transcription factor RORα enforces stability of the Th17 cell effector program by binding to a Rorc cis-regulatory element. Immunity 2022; 55:2027-2043.e9. [PMID: 36243007 DOI: 10.1016/j.immuni.2022.09.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/05/2022] [Accepted: 09/20/2022] [Indexed: 11/05/2022]
Abstract
T helper 17 (Th17) cells regulate mucosal barrier defenses but also promote multiple autoinflammatory diseases. Although many molecular determinants of Th17 cell differentiation have been elucidated, the transcriptional programs that sustain Th17 cells in vivo remain obscure. The transcription factor RORγt is critical for Th17 cell differentiation; however, it is not clear whether the closely related RORα, which is co-expressed in Th17 cells, has a distinct role. Here, we demonstrated that although dispensable for Th17 cell differentiation, RORα was necessary for optimal Th17 responses in peripheral tissues. The absence of RORα in T cells led to reductions in both RORγt expression and effector function among Th17 cells. Cooperative binding of RORα and RORγt to a previously unidentified Rorc cis-regulatory element was essential for Th17 lineage maintenance in vivo. These data point to a non-redundant role of RORα in Th17 lineage maintenance via reinforcement of the RORγt transcriptional program.
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Affiliation(s)
- Jason A Hall
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Maria Pokrovskii
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Lina Kroehling
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - Bo-Ram Kim
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Seung Yong Kim
- Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Lin Wu
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA
| | - June-Yong Lee
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
| | - Dan R Littman
- The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York, NY 10016, USA.
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6
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Huang M, Bolin S, Miller H, Ng HL. RORγ Structural Plasticity and Druggability. Int J Mol Sci 2020; 21:ijms21155329. [PMID: 32727079 PMCID: PMC7432406 DOI: 10.3390/ijms21155329] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/08/2020] [Accepted: 07/15/2020] [Indexed: 12/19/2022] Open
Abstract
Retinoic acid receptor-related orphan receptor γ (RORγ) is a transcription factor regulating the expression of the pro-inflammatory cytokine IL-17 in human T helper 17 (Th17) cells. Activating RORγ can induce multiple IL-17-mediated autoimmune diseases but may also be useful for anticancer therapy. Its deep immunological functions make RORɣ an attractive drug target. Over 100 crystal structures have been published describing atomic interactions between RORɣ and agonists and inverse agonists. In this review, we focus on the role of dynamic properties and plasticity of the RORɣ orthosteric and allosteric binding sites by examining structural information from crystal structures and simulated models. We discuss the possible influences of allosteric ligands on the orthosteric binding site. We find that high structural plasticity favors the druggability of RORɣ, especially for allosteric ligands.
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Affiliation(s)
- Mian Huang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA; (M.H.); (H.M.)
| | - Shelby Bolin
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA;
| | - Hannah Miller
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA; (M.H.); (H.M.)
| | - Ho Leung Ng
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA; (M.H.); (H.M.)
- Correspondence:
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7
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Chan YH, Chu KH, Chan KM. Ecdysteroid-mimicking compounds act as both agonists and antagonists to the crustacean ecdysone receptor. CHEMOSPHERE 2019; 237:124551. [PMID: 31549662 DOI: 10.1016/j.chemosphere.2019.124551] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
To characterize the potential endocrine-disrupting chemicals (EDCs) in the environment that interact with the crustacean ecdysone receptor (EcR), we established a method involving in silico modeling/molecular docking and in vitro reporter gene assay. Cherry shrimp (Neocaridina davidi) EcR (NdEcR) and retinoid X receptor (NdRxR) were identified and cloned for use in this method. A theoretical 3D model of NdEcR ligand-binding domain (LBD) was built in silico based on sequence homology with the established X-ray structure of insect EcR. The interaction of the NdEcR LBD with ecdysteroids, diacylhydrazine (DAH) pesticides, and other potential EDCs was evaluated using molecular docking programs. The results revealed that the ligand-binding pocket in the NdEcR LBD was flexible and adaptive for accommodating ligands of different shapes. The agonistic and antagonistic activities of the candidate compounds were further assessed by in vitro reporter gene assay using human cell lines transiently transfected with NdEcR and NdRxR expression plasmids and a reporter plasmid containing synthesized ecdysone response element. The assay was validated by the dose-dependent responses of EcR-mediated gene transcription after treating the transfected cell lines with ecdysteroids, 20-hydroxyecdysone, and ponasterone A. Examination of the candidate compounds using the reporter gene assay revealed restricted functional specificity to ecdysteroids and DAHs. Three of the tested DAH pesticides originally targeting the insect EcR were found to be weak agonists and strong antagonists of NdEcR. These results suggest that DAHs are potential EDCs for crustaceans that disrupt their ecdysteroid signals by functioning as EcR agonists or antagonists.
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Affiliation(s)
- Yuk Hang Chan
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Ka Hou Chu
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - King Ming Chan
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong.
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Fang Y, Zhang J, Li Y, Guo X, Li J, Zhong R, Zhang X. Melatonin-induced demethylation of antioxidant genes increases antioxidant capacity through RORα in cumulus cells of prepubertal lambs. Free Radic Biol Med 2019; 131:173-183. [PMID: 30472366 DOI: 10.1016/j.freeradbiomed.2018.11.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 11/05/2018] [Accepted: 11/21/2018] [Indexed: 12/25/2022]
Abstract
Physical damage and oxidative stress may occur in prepubertal cumulus cells, due to insufficient glutathione synthesis. To determine potential epigenetic mechanisms related to antioxidant effects of melatonin on ovine prepubertal cumulus cells, 30 lambs, 4-wk-old were randomly allocated into two groups: a control (C, n = 20) group and a melatonin (M, n = 10) group given a subcutaneous implant containing 18 mg melatonin. All lambs were superovulated (250 IU FSH and 250 IU eCG). Cumulus cells from germinal vesicle stage cumulus oocyte complexes (COCs) were collected by ovarian follicular aspiration and dissociated with hyaluronidase. Compared to the C group, the M group had greater superovulation, better antioxidant capacity, a higher proportion of fully expanded COCs and a lower proportion of apoptotic cumulus cells (P < 0.05). Melatonin up-regulated mRNA expression of genes for melatonin receptors MT1 and nuclear binding site RORα, antioxidants (SOD1, GPx4 and CAT) and cumulus cell expansion (PTX3, HAS2 and PTGS2), as well as Bcl2, but down-regulated expression of Bax (P < 0.05). Regarding epigenetics, there were less methylation at five CpG sites of SOD1, three CpG sites of GPx4 and two CpG sites of CAT in M versus C groups (P < 0.05), leading to lower total methylation of SOD1, GPx4 and CAT promoters region on M group (P < 0.05). In a mechanistic study, addition of MT1 or RORα antagonist increased ROS and MDA concentrations, but decreased T-AOC, GPx, CAT and T-SOD concentrations (P < 0.05), whereas there were no significant difference between the melatonin and MT2 antagonist treatment groups for T-AOC, GPx, CAT and T-SOD concentrations. Furthermore, addition of RORα agonist decreased total DNA methylation of SOD1, GPx4 and CAT, with no significant difference after MT1 agonist treatment. These studies provided new information regarding epigenetic mechanisms by which melatonin promoted ovine prepubertal cumulus cells antioxidant through RORα, both in vitro and in vivo.
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Affiliation(s)
- Yi Fang
- Jilin Provincial Key Laboratory of Grassland Farming, Northeast Institute of Geography and Agoecology, Chinese Academy of Sciences, Changchun, Jilin 130062, China
| | - Jinlong Zhang
- Animal Husbandry and Veterinary Research Institute of Tianjin, Tianjin 300412, China
| | - Yihai Li
- Animal Husbandry and Veterinary Research Institute of Tianjin, Tianjin 300412, China
| | - Xiaofei Guo
- Animal Husbandry and Veterinary Research Institute of Tianjin, Tianjin 300412, China
| | - Junjie Li
- College of animal science and technology, Agricultural University of Hebei, Baoding, Hebei 071000, China
| | - Rongzhen Zhong
- Jilin Provincial Key Laboratory of Grassland Farming, Northeast Institute of Geography and Agoecology, Chinese Academy of Sciences, Changchun, Jilin 130062, China.
| | - Xiaosheng Zhang
- Animal Husbandry and Veterinary Research Institute of Tianjin, Tianjin 300412, China.
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Castillo SO, Xiao Q, Kostrouch Z, Dozin B, Nikodem VM. A divergent role of COOH-terminal domains in Nurr1 and Nur77 transactivation. Gene Expr 2018; 7:1-12. [PMID: 9572393 PMCID: PMC6151941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Orphan nuclear receptors such as Nurr1 and Nur77 have conserved amino acid sequences in the zinc finger DNA binding domains and similar COOH-terminal regions, but have no known ligands. These receptors can bind DNA sequences (response elements) as monomers and can also heterodimerize with the retinoid X receptor to activate transcription. We report here the identification and initial characterization of a novel COOH-terminal truncated isoform of Nurr1, Nurr1a. Internal splicing of Nurr1 generates a frameshift such that a stop codon is prematurely encoded resulting in a naturally occurring COOH-terminal truncation. Embryonic and postnatal mouse brain showed both Nurr1 and Nurr1a mRNAs expressed during development. To characterize essential COOH-terminal elements that may be deleted from Nurr1a and determine function in putative ligand binding, we created COOH-terminal deletion mutants. Nurr1, Nur77, and 3'-truncated mutants bind in gel mobility shift assays to the monomeric Nur77 response element (B1A-RE). However, in transient transfection assays, a truncation of as little as 15 Nurr1 COOH-terminal amino acids diminished transcriptional activation of B1A-thymidine kinase-chloramphenicol acetyltransferase reporter. This result was not seen for a similar Nur77 deletion mutant, Nur77-586. Unlike full-length Nurr1 and Nur77, transactivation by Nur77-586 was not augmented in response to the presence of retinoid-like receptor and 9-cis-retinoic acid. Thus, the interaction of putative ligand binding and transactivation for Nurr1 and Nur77 may function differently.
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MESH Headings
- 3T3 Cells
- Alitretinoin
- Alternative Splicing
- Amino Acid Sequence
- Animals
- Base Sequence
- Binding Sites
- Chromosome Mapping
- Cloning, Molecular
- DNA/metabolism
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Mice
- Molecular Sequence Data
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nuclear Proteins/metabolism
- Nuclear Receptor Subfamily 4, Group A, Member 1
- Nuclear Receptor Subfamily 4, Group A, Member 2
- Receptors, Cytoplasmic and Nuclear
- Receptors, Retinoic Acid/metabolism
- Receptors, Steroid/chemistry
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Retinoid X Receptors
- Structure-Activity Relationship
- Transcription Factors/chemistry
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcriptional Activation
- Tretinoin/metabolism
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Affiliation(s)
- S O Castillo
- National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Genetics and Biochemistry Branch, Mechanisms of Gene Regulation Section, Bethesda, MD 20892-1766, USA
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10
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RORα2 requires LSD1 to enhance tumor progression in breast cancer. Sci Rep 2017; 7:11994. [PMID: 28931919 PMCID: PMC5607251 DOI: 10.1038/s41598-017-12344-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 09/07/2017] [Indexed: 11/30/2022] Open
Abstract
Retinoic acid-related orphan receptor α (RORα) regulates diverse physiological processes, including inflammatory responses, lipid metabolism, circadian rhythm, and cancer biology. RORα has four different isoforms which have distinct N-terminal domains but share identical DNA binding domain and ligand binding domain in human. However, lack of specific antibody against each RORα isoform makes biochemical studies on each RORα isoform remain unclear. Here, we generate RORα2-specific antibody and characterize the role of RORα2 in promoting tumor progression in breast cancer. RORα2 requires lysine specific demethylase 1 (LSD1/KDM1A) as a coactivator for transcriptional activation of RORα2 target genes, exemplified by CTNND1. Intriguingly, RORα2 and LSD1 protein levels are dramatically elevated in human breast cancer specimens compared to normal counterparts. Taken together, our studies indicate that LSD1-mediated RORα2 transcriptional activity is important to promote tumor cell migration in human breast cancer as well as breast cancer cell lines. Therefore, our data establish that suppression of LSD1-mediated RORα2 transcriptional activity may be potent therapeutic strategy to attenuate tumor cell migration in human breast cancer.
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Post-translational regulation of RORγt—A therapeutic target for the modulation of interleukin-17-mediated responses in autoimmune diseases. Cytokine Growth Factor Rev 2016; 30:1-17. [DOI: 10.1016/j.cytogfr.2016.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 01/16/2023]
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12
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Imai Y, Youn MY, Inoue K, Takada I, Kouzmenko A, Kato S. Nuclear receptors in bone physiology and diseases. Physiol Rev 2013; 93:481-523. [PMID: 23589826 PMCID: PMC3768103 DOI: 10.1152/physrev.00008.2012] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
During the last decade, our view on the skeleton as a mere solid physical support structure has been transformed, as bone emerged as a dynamic, constantly remodeling tissue with systemic regulatory functions including those of an endocrine organ. Reflecting this remarkable functional complexity, distinct classes of humoral and intracellular regulatory factors have been shown to control vital processes in the bone. Among these regulators, nuclear receptors (NRs) play fundamental roles in bone development, growth, and maintenance. NRs are DNA-binding transcription factors that act as intracellular transducers of the respective ligand signaling pathways through modulation of expression of specific sets of cognate target genes. Aberrant NR signaling caused by receptor or ligand deficiency may profoundly affect bone health and compromise skeletal functions. Ligand dependency of NR action underlies a major strategy of therapeutic intervention to correct aberrant NR signaling, and significant efforts have been made to design novel synthetic NR ligands with enhanced beneficial properties and reduced potential negative side effects. As an example, estrogen deficiency causes bone loss and leads to development of osteoporosis, the most prevalent skeletal disorder in postmenopausal women. Since administration of natural estrogens for the treatment of osteoporosis often associates with undesirable side effects, several synthetic estrogen receptor ligands have been developed with higher therapeutic efficacy and specificity. This review presents current progress in our understanding of the roles of various nuclear receptor-mediated signaling pathways in bone physiology and disease, and in development of advanced NR ligands for treatment of common skeletal disorders.
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Affiliation(s)
- Yuuki Imai
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan.
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13
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Fitzsimmons RL, Lau P, Muscat GEO. Retinoid-related orphan receptor alpha and the regulation of lipid homeostasis. J Steroid Biochem Mol Biol 2012; 130:159-68. [PMID: 21723946 DOI: 10.1016/j.jsbmb.2011.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 10/18/2022]
Abstract
Many nuclear hormone receptors (NRs) control lipid, glucose and energy homeostasis in an organ specific manner. Concordantly, dysfunctional NR signalling results in metabolic disease. The Retinoic acid receptor-related orphan receptor alpha (RORα), a member of the NR1F subgroup, is expressed in metabolic tissues. Previous studies identified the role of this NR in dyslipidemia, apo-lipoprotein metabolism and atherosclerosis. Recent data is underscoring the significant role of this orphan NR in the regulation of phase I/II metabolism (bile acids, xenobiotics, steroids etc.), adiposity, insulin signalling, and glucose tolerance. Moreover, oxygenated sterols, have been demonstrated to function as native ligands and inverse agonists. This review focuses on the rapidly emerging and evolving role of RORα in the control of lipid and glucose homeostasis in major mass metabolic tissues. Article from the special issue orphan receptors.
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Affiliation(s)
- Rebecca L Fitzsimmons
- Obesity Research Centre, Institute for Molecular Bioscience, University of Queensland, Services Rd St. Lucia, Queensland, 4072 Australia
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14
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Pawlak M, Lefebvre P, Staels B. General molecular biology and architecture of nuclear receptors. Curr Top Med Chem 2012; 12:486-504. [PMID: 22242852 PMCID: PMC3637177 DOI: 10.2174/156802612799436641] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/22/2011] [Indexed: 12/12/2022]
Abstract
Nuclear receptors (NRs) regulate and coordinate multiple processes by integrating internal and external signals, thereby maintaining homeostasis in front of nutritional, behavioral and environmental challenges. NRs exhibit strong similarities in their structure and mode of action: by selective transcriptional activation or repression of cognate target genes, which can either be controlled through a direct, DNA binding-dependent mechanism or through crosstalk with other transcriptional regulators, NRs modulate the expression of gene clusters thus achieving coordinated tissue responses. Additionally, non genomic effects of NR ligands appear mediated by ill-defined mechanisms at the plasma membrane. These effects mediate potential therapeutic effects as small lipophilic molecule targets, and many efforts have been put in elucidating their precise mechanism of action and pathophysiological roles. Currently, numerous nuclear receptor ligand analogs are used in therapy or are tested in clinical trials against various diseases such as hypertriglyceridemia, atherosclerosis, diabetes, allergies and cancer and others.
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Affiliation(s)
- Michal Pawlak
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
| | - Philippe Lefebvre
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
| | - Bart Staels
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
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15
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Benderdour M, Fahmi H, Beaudet F, Fernandes JC, Shi Q. Nuclear receptor retinoid-related orphan receptor α1 modulates the metabolic activity of human osteoblasts. J Cell Biochem 2011; 112:2160-9. [DOI: 10.1002/jcb.23141] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Lau P, Fitzsimmons RL, Pearen MA, Watt MJ, Muscat GEO. Homozygous staggerer (sg/sg) mice display improved insulin sensitivity and enhanced glucose uptake in skeletal muscle. Diabetologia 2011; 54:1169-80. [PMID: 21279323 PMCID: PMC3071927 DOI: 10.1007/s00125-011-2046-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 12/03/2010] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Homozygous staggerer (sg/sg) mice, which have decreased and dysfunctional Rorα (also known as Rora) expression in all tissues, display a lean and dyslipidaemic phenotype. They are also resistant to (high fat) diet-induced obesity. We explored whether retinoic acid receptor-related orphan receptor (ROR) α action in skeletal muscle was involved in the regulation of glucose metabolism. METHODS We used a three-armed genomic approach, including expression profiling, ingenuity analysis and quantitative PCR validation to identify the signalling pathway(s) in skeletal muscle that are perturbed in sg/sg mice. Moreover, western analysis, functional insulin and glucose tolerance tests, and ex vivo glucose uptake assays were used to phenotypically characterise the impact of aberrant v-AKT murine thymoma viral oncogene homologue (AKT) signalling. RESULTS Homozygous and heterozygous (sg/sg and sg/+) animals exhibited decreased fasting blood glucose levels, mildly improved glucose tolerance and increased insulin sensitivity. Illumina expression profiling and bioinformatic analysis indicated the involvement of RORα in metabolic disease and phosphatidylinositol 3-kinase-AKT signalling. Quantitative PCR and western analysis validated increased AKT2 (mRNA and protein) and phosphorylation in sg/sg mice in the basal state. This was associated with increased expression of Tbc1d1 and Glut4 (also known as Slc2a4) mRNA and protein. Finally, in agreement with the phenotype, we observed increased (absolute) levels of AKT and phosphorylated AKT (in the basal and insulin stimulated states), and of (ex vivo) glucose uptake in skeletal muscle from sg/sg mice relative to wild-type littermates. CONCLUSIONS/INTERPRETATION We propose that Rorα plays an important role in regulation of the AKT2 signalling cascade, which controls glucose uptake in skeletal muscle.
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Affiliation(s)
- P. Lau
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - R. L. Fitzsimmons
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - M. A. Pearen
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
| | - M. J. Watt
- Department of Physiology, Monash University, Clayton, VIC Australia
| | - G. E. O. Muscat
- Obesity Research Centre, Institute for Molecular Bioscience, The University of Queensland, Services Rd, St Lucia, Queensland, 4072 Australia
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17
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Raichur S, Fitzsimmons RL, Myers SA, Pearen MA, Lau P, Eriksson N, Wang SM, Muscat GEO. Identification and validation of the pathways and functions regulated by the orphan nuclear receptor, ROR alpha1, in skeletal muscle. Nucleic Acids Res 2010; 38:4296-312. [PMID: 20338882 PMCID: PMC2910057 DOI: 10.1093/nar/gkq180] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The retinoic acid receptor-related orphan receptor (ROR) alpha has been demonstrated to regulate lipid metabolism. We were interested in the RORα1 dependent physiological functions in skeletal muscle. This major mass organ accounts for ∼40% of the total body mass and significant levels of lipid catabolism, glucose disposal and energy expenditure. We utilized the strategy of targeted muscle-specific expression of a truncated (dominant negative) RORα1ΔDE in transgenic mice to investigate RORα1 signaling in this tissue. Expression profiling and pathway analysis indicated that RORα influenced genes involved in: (i) lipid and carbohydrate metabolism, cardiovascular and metabolic disease; (ii) LXR nuclear receptor signaling and (iii) Akt and AMPK signaling. This analysis was validated by quantitative PCR analysis using TaqMan low-density arrays, coupled to statistical analysis (with Empirical Bayes and Benjamini–Hochberg). Moreover, westerns and metabolic profiling were utilized to validate the genes, proteins and pathways (lipogenic, Akt, AMPK and fatty acid oxidation) involved in the regulation of metabolism by RORα1. The identified genes and pathways were in concordance with the demonstration of hyperglycemia, glucose intolerance, attenuated insulin-stimulated phosphorylation of Akt and impaired glucose uptake in the transgenic heterozygous Tg-RORα1ΔDE animals. In conclusion, we propose that RORα1 is involved in regulating the Akt2-AMPK signaling pathways in the context of lipid homeostasis in skeletal muscle.
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Affiliation(s)
- S Raichur
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia
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18
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Odawara H, Iwasaki T, Horiguchi J, Rokutanda N, Hirooka K, Miyazaki W, Koibuchi Y, Shimokawa N, Iino Y, Takeyoshi I, Koibuchi N. Activation of aromatase expression by retinoic acid receptor-related orphan receptor (ROR) alpha in breast cancer cells: identification of a novel ROR response element. J Biol Chem 2009; 284:17711-9. [PMID: 19439415 PMCID: PMC2719410 DOI: 10.1074/jbc.m109.009241] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/30/2009] [Indexed: 11/06/2022] Open
Abstract
Estrogen is a key regulator of the proliferation and differentiation of breast cancer cells. In addition to the estrogen supply from the ovary, estrogen is produced locally from androgen by aromatase. However, the regulation of aromatase gene expression in breast cancer has not yet been fully clarified. Retinoic acid receptor-related orphan receptor (ROR) alpha plays an important role in the differentiation of many organs by regulating the transcription of target genes. Because aromatase and RORalpha are expressed in breast cancer, the effect of RORalpha on aromatase gene expression was studied. RORalpha significantly augmented the expression of aromatase mRNA, particularly those containing exon I.4, in MCF7 cells, and aromatase activities in T47D and MCF7 cells. RORalpha also stimulated the proliferation of these cells. Transient transfection-based reporter gene assays using the promoter at exon I.4 showed that RORalpha augmented the transcription. A series of truncated mutation studies revealed that RORalpha activated the transcription through -147 to +14 bp of the promoter I.4. Furthermore, RORalpha bound to the fragment containing -119 to -107 bp of the promoter in vitro, indicating that this region may contain a novel ROR response element. Chromatin immunoprecipitation assay showed that RORalpha bound to the region containing this site of the promoter I.4 in MCF7 cells. Moreover, we examined clinical samples and found a correlation between RORalpha and aromatase expression. These results suggest that RORalpha directly activates the aromatase expression to accelerate the local production of estrogen, which results in the proliferation of breast cancer cells.
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MESH Headings
- Aromatase/genetics
- Aromatase/metabolism
- Binding Sites
- Blotting, Western
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Cell Proliferation
- Chromatin Immunoprecipitation
- Electrophoretic Mobility Shift Assay
- Gene Expression Regulation, Neoplastic/physiology
- Humans
- Luciferases
- Mutation/genetics
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Promoter Regions, Genetic/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Response Elements/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- Hiroki Odawara
- From the Departments of Thoracic and Visceral Organ Surgery
| | | | - Jun Horiguchi
- From the Departments of Thoracic and Visceral Organ Surgery
| | - Nana Rokutanda
- From the Departments of Thoracic and Visceral Organ Surgery
| | | | | | - Yukio Koibuchi
- From the Departments of Thoracic and Visceral Organ Surgery
| | | | - Yuichi Iino
- Emergency Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
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19
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Jetten AM. Retinoid-related orphan receptors (RORs): critical roles in development, immunity, circadian rhythm, and cellular metabolism. NUCLEAR RECEPTOR SIGNALING 2009; 7:e003. [PMID: 19381306 PMCID: PMC2670432 DOI: 10.1621/nrs.07003] [Citation(s) in RCA: 511] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 03/18/2009] [Indexed: 12/11/2022]
Abstract
The last few years have witnessed a rapid increase in our knowledge of the retinoid-related orphan receptors RORα, -β, and -γ (NR1F1-3), their mechanism of action, physiological functions, and their potential role in several pathologies. The characterization of ROR-deficient mice and gene expression profiling in particular have provided great insights into the critical functions of RORs in the regulation of a variety of physiological processes. These studies revealed that RORα plays a critical role in the development of the cerebellum, that both RORα and RORβ are required for the maturation of photoreceptors in the retina, and that RORγ is essential for the development of several secondary lymphoid tissues, including lymph nodes. RORs have been further implicated in the regulation of various metabolic pathways, energy homeostasis, and thymopoiesis. Recent studies identified a critical role for RORγ in lineage specification of uncommitted CD4+ T helper cells into Th17 cells. In addition, RORs regulate the expression of several components of the circadian clock and may play a role in integrating the circadian clock and the rhythmic pattern of expression of downstream (metabolic) genes. Study of ROR target genes has provided insights into the mechanisms by which RORs control these processes. Moreover, several reports have presented evidence for a potential role of RORs in several pathologies, including osteoporosis, several autoimmune diseases, asthma, cancer, and obesity, and raised the possibility that RORs may serve as potential targets for chemotherapeutic intervention. This prospect was strengthened by recent evidence showing that RORs can function as ligand-dependent transcription factors.
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Affiliation(s)
- Anton M Jetten
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.
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20
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Nacusi LP, Debes JD. Primers on molecular pathways: nuclear receptors in pancreatic cancer. The ligand-independent way. Pancreatology 2008; 8:422-4. [PMID: 18714175 DOI: 10.1159/000151479] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nuclear receptors (NRs) are ligand-activated transcription factors that regulate gene expression. These receptors share a quite similar structure and mechanism of action. Upon ligand binding, NRs translocate from the cytoplasm to the nucleus and bind to specific DNA sequences that regulate expression of different genes. In the absence of ligand the cascade of signaling events is different and either activation or repression may occur. Interestingly, several NRs are implicated in the pathogenesis of pancreatic cancer (PanCa). Specifically, androgen and estrogen receptor-related pathways are active in patients with pancreatic tumors, thus representing a suitable target for PanCa treatment. Although anti-hormone treatment has a modest effect on PanCa, ligand-independent activation of NRs remains overall unexplored in this disease.
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Affiliation(s)
- Lucas P Nacusi
- Department of Urology, Mayo Medical College of Medicine, Rochester, MN 55905, USA.
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21
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Sundrud MS, Rao A. Regulation of T helper 17 differentiation by orphan nuclear receptors: it's not just ROR gamma t anymore. Immunity 2008; 28:5-7. [PMID: 18199410 DOI: 10.1016/j.immuni.2007.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
T cells that produce IL-17 (T helper 17 cells) are implicated in autoimmune pathogenesis. In this issue of Immunity, Yang et al. (2008) report that the closely related orphan nuclear receptors ROR alpha and ROR gamma t work together to regulate T helper (Th)17 cell differentiation.
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Affiliation(s)
- Mark S Sundrud
- Department of Pathology, Harvard Medical School, and Immune Disease Institute, Boston, MA 02115, USA
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22
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Lechtken A, Hörnig M, Werz O, Corvey N, Zündorf I, Dingermann T, Brandes R, Steinhilber D. Extracellular signal-regulated kinase-2 phosphorylates RORalpha4 in vitro. Biochem Biophys Res Commun 2007; 358:890-6. [PMID: 17512500 DOI: 10.1016/j.bbrc.2007.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 05/03/2007] [Indexed: 11/19/2022]
Abstract
The retinoic acid related orphan receptor RORalpha activates transcription of genes that play an important role in cerebellar development, the protection against age-related degenerative processes, the regulation of inflammatory responses, and is one of the pivotal participants that control the circadian rhythmicity in the core-clock of mammals. We identified the extracellular signal-regulated kinase 2 (ERK-2) as RORalpha4 phosphorylating kinase in vitro. The primary sequence of RORalpha4 contains an ERK-2 recognition motif (P-L-T(128)-P) within the hinge domain, and mutation of Thr-128 to Ala prevents RORalpha4 phosphorylation by ERK. The RORalpha4-T128A mutant exhibits an increased DNA-binding affinity, an increased transcriptional activity and, in the interplay with the opponent RevErbalpha, acts as a stronger competitor at ROR response elements than RORalpha4-WT.
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Affiliation(s)
- Adriane Lechtken
- Institute of Pharmaceutical Chemistry/ZAFES, Johann Wolfgang Goethe University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany
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23
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Benoit G, Cooney A, Giguere V, Ingraham H, Lazar M, Muscat G, Perlmann T, Renaud JP, Schwabe J, Sladek F, Tsai MJ, Laudet V. International Union of Pharmacology. LXVI. Orphan nuclear receptors. Pharmacol Rev 2006; 58:798-836. [PMID: 17132856 DOI: 10.1124/pr.58.4.10] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Half of the members of the nuclear receptors superfamily are so-called "orphan" receptors because the identity of their ligand, if any, is unknown. Because of their important biological roles, the study of orphan receptors has attracted much attention recently and has resulted in rapid advances that have helped in the discovery of novel signaling pathways. In this review we present the main features of orphan receptors, discuss the structure of their ligand-binding domains and their biological functions. The paradoxical existence of a pharmacology of orphan receptors, a rapidly growing and innovative field, is highlighted.
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Affiliation(s)
- Gérard Benoit
- Unité Mixte de Recherche 5161 du Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique 1237, Institut Fédératif de Recherche 128 BioSciences Lyon-Gerland, Ecole Normale Supérieure de Lyon, Lyon, France
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24
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Boukhtouche F, Doulazmi M, Frederic F, Dusart I, Brugg B, Mariani J. RORalpha, a pivotal nuclear receptor for Purkinje neuron survival and differentiation: from development to ageing. THE CEREBELLUM 2006; 5:97-104. [PMID: 16818384 DOI: 10.1080/14734220600750184] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
RORalpha (Retinoid-related Orphan Receptor) is a transcription factor belonging to the superfamily of nuclear receptors. The spontaneous staggerer (sg) mutation, which consists of a deletion in the Rora gene, has been shown to cause the loss of function of the RORalpha protein. The total loss of RORalpha expression leads to cerebellar developmental defects, particularly to a dramatic decreased survival of Purkinje cells and an early block in the differentiation process. This review focuses on recent studies which position RORalpha as a pivotal factor controlling Purkinje cell survival and differentiation, from development to ageing.
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Affiliation(s)
- Fatiha Boukhtouche
- Université Pierre et Marie Curie-Paris6, UMR 7102 - Neurobiologie des Processus Adaptatifs (NPA): CNRS, UMR 7102-NPA, 9, quai St-Bernard, Paris, F-75005, France
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25
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Irmak MK, Sizlan A. Essential hypertension seems to result from melatonin-induced epigenetic modifications in area postrema. Med Hypotheses 2006; 66:1000-7. [PMID: 16434146 DOI: 10.1016/j.mehy.2005.10.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Accepted: 10/21/2005] [Indexed: 02/07/2023]
Abstract
Essential hypertension is a complex multifactorial disorder with epigenetic and environmental factors contributing to its prevalence. Epigenetic system is a genetic regulatory mechanism that allows humans to maintain extraordinarily stable patterns of gene expression over many generations. Sympathetic nervous system plays a major role in the maintenance of hypertension and the rostral ventrolateral medulla is the main source of this sympathetic activation. A possible mechanism to explain the sympathetic hyperactivity in the rostral ventrolateral medulla is an action of the area postrema. Area postrema seems to be the region where a shift of the set-point to a higher operating pressure occurs resulting in hypertension. But, how can a shift occur in the area postrema. We propose that melatonin-induced epigenetic modifications in the neurons of area postrema plays a role in this shift. Area postrema is reported to contain high levels of melatonin receptors that play a role in the epigenetic modifications in certain cells. Environmental stressors cause epigenetic modifications in the neurons of area postrema via the pineal hormone melatonin and these changes lead to a shift in the set-point to a higher operating pressure. This signal is then sent via efferent projections to key medullary sympathetic nuclei in rostral ventrolateral medulla resulting in increases in sympathetic nerve activity. This model may explain the long-term alterations in sympathetic activity in essential hypertension.
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Affiliation(s)
- M K Irmak
- Department of Histology and Embryology, School of Medicine, Gulhane Military Medical Academy, GATA Histoloji AD, Etlik Ankara, Turkey. mkirmak@gata,edu,tr
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26
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Jetten AM, Joo JH. Retinoid-related Orphan Receptors (RORs): Roles in Cellular Differentiation and Development. ADVANCES IN DEVELOPMENTAL BIOLOGY (AMSTERDAM, NETHERLANDS) 2006; 16:313-355. [PMID: 18418469 DOI: 10.1016/s1574-3349(06)16010-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Retinoid-related orphan receptors RORalpha, -beta, and -gamma are transcription factors belonging to the steroid hormone receptor superfamily. During embryonic development RORs are expressed in a spatial and temporal manner and are critical in the regulation of cellular differentiation and the development of several tissues. RORalpha plays a key role in the development of the cerebellum particularly in the regulation of the maturation and survival of Purkinje cells. In RORalpha-deficient mice, the reduced production of sonic hedgehog by these cells appears to be the major cause of the decreased proliferation of granule cell precursors and the observed cerebellar atrophy. RORalpha has been implicated in the regulation of a number of other physiological processes, including bone formation. RORbeta expression is largely restricted to several regions of the brain, the retina, and pineal gland. Mice deficient in RORbeta develop retinal degeneration that results in blindness. RORgamma is essential for lymph node organogenesis. In the intestine RORgamma is required for the formation of several other lymphoid tissues: Peyer's patches, cryptopatches, and isolated lymphoid follicles. RORgamma plays a key role in the generation of lymphoid tissue inducer (LTi) cells that are essential for the development of these lymphoid tissues. In addition, RORgamma is a critical regulator of thymopoiesis. It controls the differentiation of immature single-positive thymocytes into double-positive thymocytes and promotes the survival of double-positive thymocytes by inducing the expression of the anti-apoptotic gene Bcl-X(L). Interestingly, all three ROR receptors appear to play a role in the control of circadian rhythms. RORalpha positively regulates the expression of Bmal1, a transcription factor that is critical in the control of the circadian clock. This review intends to provide an overview of the current status of the functions RORs have in these biological processes.
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Affiliation(s)
- Anton M Jetten
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
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27
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Chauvet C, Bois-Joyeux B, Berra E, Pouyssegur J, Danan JL. The gene encoding human retinoic acid-receptor-related orphan receptor alpha is a target for hypoxia-inducible factor 1. Biochem J 2005; 384:79-85. [PMID: 15270719 PMCID: PMC1134090 DOI: 10.1042/bj20040709] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Retinoic acid-receptor-related orphan receptor (ROR) alpha is a nuclear receptor involved in many pathophysiological processes such as cerebellar ataxia, inflammation, atherosclerosis and angiogenesis. In the present study we first demonstrate that hypoxia increases the amount of Rora transcripts in a wide panel of cell lines derived from diverse tissues. In addition, we identified a functional promoter sequence upstream of the first exon of the human Rora gene, spanning -487 and -45 from the translation initiation site of RORalpha1. When cloned in a luciferase reporter vector, this sequence allowed the efficient transcription of the luciferase gene in several cell lines. Interestingly, the activity of the Rora promoter was enhanced by hypoxia in HepG2 human hepatoma cells, and this effect was dependent on an HRE (hypoxia response element) spanning from -229 to -225. Using electrophoretic-mobility-shift assays, we showed that HIF-1 (hypoxia-inducible factor 1), which plays a key role in the transcriptional response to hypoxia, bound to this HRE. Overexpression of HIF-1alpha increased the activity of the Rora promoter through the HRE. Overexpression of a dominant-negative form of HIF-1alpha producing transcriptionally inactive HIF-1alpha/HIF-1beta dimers abolished hypoxic activation of the Rora promoter. This indicated that HIF-1 is involved in the response of RORalpha to hypoxia. Taken together, our data reveal Rora as a new HIF-1 target gene. This illustrates, at the molecular level, the existence of cross-talk between signalling pathways mediated by HIF-1 and those mediated by nuclear receptors.
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Affiliation(s)
- Caroline Chauvet
- *Centre National de La Recherche Scientifique UPR9078, IRNEM (Institut fédératif de recherche Necker Enfants-Malades), Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75015 Paris, Cédex 15, France
| | - Brigitte Bois-Joyeux
- *Centre National de La Recherche Scientifique UPR9078, IRNEM (Institut fédératif de recherche Necker Enfants-Malades), Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75015 Paris, Cédex 15, France
| | - Edurne Berra
- †Institute of Signaling, Developmental Biology and Cancer Research, Centre National de La Recherche Scientifique UMR6543, Centre Antoine Lacassagne, 33 avenue Valombrose, 06189 Nice, France
| | - Jacques Pouyssegur
- †Institute of Signaling, Developmental Biology and Cancer Research, Centre National de La Recherche Scientifique UMR6543, Centre Antoine Lacassagne, 33 avenue Valombrose, 06189 Nice, France
| | - Jean-Louis Danan
- *Centre National de La Recherche Scientifique UPR9078, IRNEM (Institut fédératif de recherche Necker Enfants-Malades), Faculté de Médecine Necker-Enfants Malades, 156 rue de Vaugirard, 75015 Paris, Cédex 15, France
- To whom correspondence should be addressed (email )
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28
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Brake PB, Bair SR, Mellon SH. DNA sequence-dependent regulation of SF-1-mediated transcription. DNA Cell Biol 2005; 24:148-60. [PMID: 15767781 DOI: 10.1089/dna.2005.24.148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rat P450c17 gene transcription is regulated by several nuclear factors, including steroidogenic factor-1 (SF-1), nerve growth factor-inducible protein B (NGF-IB, Nurr77), COUP-TF, SET, and Ku autoimmune antigen. A region of this gene, -447/-419, that mediates both basal and cAMP-stimulated transcription, contains two binding sites for orphan nuclear receptors. While SF-1 activates transcription through a single binding site, we show that both binding sites at -447/-419 are required for transcriptional activation by SF-1 and cAMP. Both SF-1 and a novel factor, Steroidogenic Factor-Inducer of Transcription-2 (StF-IT-2) bind to this region, suggesting that a DNA-dependent interaction between StF-IT-2 and SF-1 may be required for full transcriptional activity. Each of the two orphan nuclear receptor sites -429/-424 and at -444/-439 are sufficient for SF-1 binding but are insufficient for SF-1-mediated transcription. Increasing the distance between or changing the orientation of these two sites does not affect basal or SF-1-stimulated activity. Circular permutation analysis, which measures the degree of DNA bending caused by protein binding, indicates that SF-1 binding to -447/-419 induces a different degree of DNA bending than it does at another SF-1-responsive site. However, similar domains of the SF-1 protein are required for its actions at these two regions. Southwestern blots suggest that StF-IT-2 is a approximately 33 kDa protein, and gel shift assays suggest it is expressed primarily in the gonad and brain early in rodent development. These data suggest that the mechanism by which SF-1 stimulates transcription is DNA sequence dependent, and may require additional proteins, such as StF-IT-2, for activation at specific regions of DNA.
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Affiliation(s)
- Paul B Brake
- Department of Obstetrics, Gynecology, and Reproductive Sciences, The Center for Reproductive Sciences, University of California, San Francisco, California 94143, USA
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29
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Irmak MK, Topal T, Oter S. Melatonin seems to be a mediator that transfers the environmental stimuli to oocytes for inheritance of adaptive changes through epigenetic inheritance system. Med Hypotheses 2005; 64:1138-43. [PMID: 15823703 DOI: 10.1016/j.mehy.2004.12.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Accepted: 12/21/2004] [Indexed: 10/25/2022]
Abstract
Possibility of inheritance of epigenetic modifications have led us to consider that adaptive geographic variations in humans may result from interactions between environmental factors and epigenetic inheritance system. In this system melatonin seems to be a mediator that transfers the environmental stimuli to germ cells (oocytes). While environmental factors produce modifications in the body, they simultaneously induce epigenetic modifications in the oocytes with the help of melatonin, and these changes are inherited to offspring. In this way, adaptive changes could be passed on to the next generation. This kind of heritable long-term changes is generally labeled biological adaptation. But, how can melatonin cause epigenetic changes in oocytes? We suggest that melatonin induces epigenetic modifications by affecting the nuclear melatonin receptors that can in turn change the superstructure of DNA. It was previously suggested that biological adaptation is limited to neural crest derivatives such as, craniofacial tissues, melanocytes, and structures related to stature, hair form and body proportions. Thus, inheritance of adaptive changes is possible only where environmental factors affect the neural crest derivatives, including the cells that produce the next generation.
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MESH Headings
- Acetylcholine/physiology
- Adaptation, Physiological/genetics
- Altitude
- Cell Lineage
- Cell Nucleus/metabolism
- DNA Methylation
- DNA-Binding Proteins/physiology
- Environmental Exposure
- Epigenesis, Genetic/genetics
- Epigenesis, Genetic/physiology
- Female
- Germ-Line Mutation
- Humans
- Light
- Melatonin/metabolism
- Melatonin/physiology
- Models, Biological
- Models, Genetic
- Neural Crest/cytology
- Norepinephrine/physiology
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Oocytes/physiology
- Ovarian Follicle/chemistry
- Pineal Gland/metabolism
- Receptors, Cytoplasmic and Nuclear
- Receptors, Melatonin/physiology
- Receptors, Retinoic Acid/physiology
- Retina/radiation effects
- Seasons
- Secretory Rate/drug effects
- Secretory Rate/radiation effects
- Skin Pigmentation
- Temperature
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Affiliation(s)
- M K Irmak
- Department of Histology and Embryology, School of Medicine, Gulhane Military Medical Academy, 06018-Etlik Ankara, Turkey.
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30
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Lau P, Nixon SJ, Parton RG, Muscat GEO. RORalpha regulates the expression of genes involved in lipid homeostasis in skeletal muscle cells: caveolin-3 and CPT-1 are direct targets of ROR. J Biol Chem 2004; 279:36828-40. [PMID: 15199055 DOI: 10.1074/jbc.m404927200] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The staggerer mice carry a deletion in the RORalpha gene and have a prolonged humoral response, overproduce inflammatory cytokines, and are immunodeficient. Furthermore, the staggerer mice display lowered plasma apoA-I/-II, decreased plasma high density lipoprotein cholesterol and triglycerides, and develop hypo-alpha-lipoproteinemia and atherosclerosis. However, relatively little is known about RORalpha in the context of target tissues, target genes, and lipid homeostasis. For example, RORalpha is abundantly expressed in skeletal muscle, a major mass peripheral tissue that accounts for approximately 40% of total body weight and 50% of energy expenditure. This lean tissue is a primary site of glucose disposal and fatty acid oxidation. Consequently, muscle has a significant role in insulin sensitivity, obesity, and the blood-lipid profile. In particular, the role of RORalpha in skeletal muscle metabolism has not been investigated, and the contribution of skeletal muscle to the ROR-/- phenotype has not been resolved. We utilize ectopic dominant negative RORalpha expression in skeletal muscle cells to understand the regulatory role of RORs in this major mass peripheral tissue. Exogenous dominant negative RORalpha expression in skeletal muscle cells represses the endogenous levels of RORalpha and -gamma mRNAs and ROR-dependent gene expression. Moreover, we observed attenuated expression of many genes involved in lipid homeostasis. Furthermore, we show that the muscle carnitine palmitoyltransferase-1 and caveolin-3 promoters are directly regulated by ROR and coactivated by p300 and PGC-1. This study implicates RORs in the control of lipid homeostasis in skeletal muscle. In conclusion, we speculate that ROR agonists would increase fatty acid catabolism in muscle and suggest selective activators of ROR may have therapeutic utility in the treatment of obesity and atherosclerosis.
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Affiliation(s)
- Patrick Lau
- Institute for Molecular Bioscience, Division of Molecular Genetics and Development, School of Biomedical Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
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31
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Nakajima Y, Ikeda M, Kimura T, Honma S, Ohmiya Y, Honma KI. Bidirectional role of orphan nuclear receptor RORalpha in clock gene transcriptions demonstrated by a novel reporter assay system. FEBS Lett 2004; 565:122-6. [PMID: 15135064 DOI: 10.1016/j.febslet.2004.03.083] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 03/25/2004] [Accepted: 03/26/2004] [Indexed: 10/26/2022]
Abstract
Circadian rhythms are generated by an extremely complicated transcription-translation feedback loop. To precisely analyze the molecular mechanisms of the circadian clock, it is critical to monitor multiple gene expressions and/or interactions with their transcription factors simultaneously. We have developed a novel reporter assay system, the tricolor reporter in vitro assay system, which consists of green- and red-emitting Phrixothrix luciferases as dual reporters and blue-emitting Renilla luciferase as internal control. We have successfully employed this system in analyzing the effects of clock gene products on the enhancer elements of Per1 and Bmal1 promoters. The results indicate that the orphan nuclear receptor RORalpha regulates bidirectionally Bmal1 (positively) and Per1 (negatively) transcriptions simultaneously.
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Affiliation(s)
- Yoshihiro Nakajima
- Cell Dynamics Research Group, Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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32
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Boukhtouche F, Mariani J, Tedgui A. The “CholesteROR” Protective Pathway in the Vascular System. Arterioscler Thromb Vasc Biol 2004; 24:637-43. [PMID: 14751813 DOI: 10.1161/01.atv.0000119355.56036.de] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Retinoic acid receptor-related Orphan Receptor α (RORα) is a member of the nuclear hormone receptor superfamily. RORα has long been considered as a constitutive activator of transcription in the absence of exogenous ligand; however, cholesterol has recently been identified as a natural ligand of RORα. The spontaneous
staggerer
(sg/sg) mutation is a deletion in the Rora gene that prevents the translation of the ligand-binding domain (LBD), leading to the loss of RORα activity. The homozygous Rora
sg/sg
mutant mouse, of which the most obvious phenotype is ataxia associated with cerebellar degeneration, also displays a variety of other phenotypes, including several vascular ones; in particular, dysfunction of smooth muscle cells and enhanced susceptibility to atherosclerosis. Moreover, RORα appears to participate in the regulation of plasma cholesterol levels, and has been shown to positively regulate apolipoprotein (apo)A-I and apoC-III gene expression. Yet its activity is regulated by cholesterol itself, making RORα an intracellular cholesterol target.
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MESH Headings
- Animals
- Apolipoprotein A-I/biosynthesis
- Apolipoprotein A-I/genetics
- Apolipoprotein C-III
- Apolipoproteins C/biosynthesis
- Apolipoproteins C/genetics
- Arteriosclerosis/genetics
- Arteriosclerosis/metabolism
- Cholesterol/metabolism
- Collateral Circulation/physiology
- Feedback, Physiological
- Gene Expression Regulation/physiology
- Genetic Predisposition to Disease
- Humans
- Inflammation/metabolism
- Mice
- Mice, Neurologic Mutants
- Models, Biological
- Muscle, Skeletal/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Purkinje Cells/metabolism
- Receptors, Cytoplasmic and Nuclear/deficiency
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Spinocerebellar Degenerations/genetics
- Spinocerebellar Degenerations/metabolism
- Trans-Activators/deficiency
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription, Genetic/physiology
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Affiliation(s)
- Fatiha Boukhtouche
- Laboratoire Développement et Vieillissement du Système Nerveux, Université P. & M. Curie-CNRS, UMR NPA 7102, case 14, 9 quai Saint Bernard, 75005 Paris, France
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33
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Abstract
Nuclear orphan receptors represent a large and diverse subgroup in the nuclear receptor superfamily. Although putative ligands for these orphan members remain to be identified, some of these receptors possess intrinsic activating, inhibitory, or dual regulatory functions in development, differentiation, homeostasis, and reproduction. In particular, gene-silencing events elicited by chicken ovalbumin upstream promoter-transcription factors (COUP-TFs); dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (DAX-1); germ cell nuclear factor (GCNF); short heterodimer partner (SHP); and testicular receptors 2 and 4 (TR2 and TR4) are among the best characterized. These orphan receptors are critical in controlling basal activities or hormonal responsiveness of numerous target genes. They employ multiple and distinct mechanisms to mediate target gene repression. Complex cross-talk exists between these orphan receptors at their cognate DNA binding elements and an array of steroid?nonsteroid hormone receptors, other transcriptional activators, coactivators and corepressors, histone modification enzyme complexes, and components of basal transcriptional components. Therefore, perturbation induced by these orphan receptors at multiple levels, including DNA binding activities, receptor homo- or heterodimerization, recruitment of cofactor proteins, communication with general transcriptional machinery, and changes at histone acetylation status and chromatin structures, may contribute to silencing of target gene expression in a specific promoter or cell-type context. Moreover, the findings derived from gene-targeting studies have demonstrated the significance of these orphan receptors' function in physiologic settings. Thus, COUP-TFs, DAX-1, GCNF, SHP, and TR2 and 4 are known to be required for multiple physiologic and biologic functions, including neurogenesis and development of the heart and vascular system steroidogenesis and sex determination, gametogenesis and embryonic development, and cholesterol?lipid homeostasis.
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MESH Headings
- Animals
- COUP Transcription Factor I
- COUP Transcription Factors
- DAX-1 Orphan Nuclear Receptor
- DNA-Binding Proteins/metabolism
- Gametogenesis/physiology
- Gene Expression/physiology
- Gene Silencing/physiology
- Humans
- Models, Molecular
- Nuclear Receptor Subfamily 2, Group C, Member 1
- Nuclear Receptor Subfamily 6, Group A, Member 1
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid/metabolism
- Receptors, Steroid/metabolism
- Receptors, Thyroid Hormone/metabolism
- Repressor Proteins/metabolism
- Transcription Factors/metabolism
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Affiliation(s)
- Ying Zhang
- Section on Molecular Endocrinology, Endocrinology, and Reproduction Research Branch, National Institutes of Health, Bethesda, Maryland 20892, USA
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34
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Swevers L, Iatrou K. The ecdysone regulatory cascade and ovarian development in lepidopteran insects: insights from the silkmoth paradigm. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:1285-1297. [PMID: 14599500 DOI: 10.1016/j.ibmb.2003.06.012] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The developing ovariole of the silkmoth Bombyx mori represents an excellent model for studies on the changes that occur in gene expression during the execution of long-term developmental programs. All stages of follicle development, which differ from each other by 2-2.5 h of developmental time, are organized in a single array and can be isolated simultaneously for physiological, biochemical and gene expression studies from a single animal. Recently, significant progress has been made toward the understanding of the hormonal regulation and autonomous implementation of the developmental program that governs follicular cell differentiation during oogenesis in Bombyx. In this review, the developmental career of the ovarian follicle during pharate adult development is discussed in view of the new physiological, biochemical and gene expression data that have recently accumulated. An overview is presented of the changes in expression of structural and regulatory genes and their hormonal regulation in the developing follicle during the transitions among the broad developmental periods of previtellogenesis, vitellogenesis and choriogenesis. Ovarian development in silkmoth pharate adults is induced by 20-hydroxy-ecdysone (20E) through the activation of a regulatory cascade similar to the one observed during Drosophila development. The transition from previtellogenesis to vitellogenesis corresponds to a late response to the hormone and is characterized by the induction of the expression of a unique isoform of the nuclear receptor BmHR3 and the follicular cell-specific yolk protein ESP. The transition from early to middle and late vitellogenesis and choriogenesis, on the other hand, is regulated by positively and negatively acting intra- and extra-ovarian factors. In vitro cultures of developing ovarioles reveal the requirement for the presence of an as yet unidentified growth factor(s) in the hemolymph, while the follicle developmental arrest that is observed after treatment with the ecdysone agonist tebufenozide indicates the requirement for a decline in the level of 20E. The initiation of choriogenesis is characterized by the transcriptional activation of the gene BmGATAbeta that encodes GATA transcription factors, and the chorion genes in the follicular cells. Furthermore, modulation of the activity of BmGATAbeta at the posttranscriptional level is crucial for the stage-specific activation of chorion genes during late choriogenesis. The developing ovariole of the silkmoth is, therefore, emerging as an important model for the study of insect oogenesis and the action of the steroid hormone 20E at the molecular level.
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Affiliation(s)
- Luc Swevers
- Institute of Biology, National Centre for Scientific Research "Demokritos", Aghia Paraskevi Attikis, 153 10 Athens, Greece.
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35
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Kallen JA, Schlaeppi JM, Bitsch F, Geisse S, Geiser M, Delhon I, Fournier B. X-ray structure of the hRORalpha LBD at 1.63 A: structural and functional data that cholesterol or a cholesterol derivative is the natural ligand of RORalpha. Structure 2002; 10:1697-707. [PMID: 12467577 DOI: 10.1016/s0969-2126(02)00912-7] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The retinoic acid-related orphan receptor alpha (RORalpha) is an orphan member of the subfamily 1 of nuclear hormone receptors. No X-ray structure of RORalpha has been described so far, and no ligand has been identified. We describe the first crystal structure of the ligand binding domain (LBD) of RORalpha, at 1.63 A resolution. This structure revealed a ligand present in the ligand binding pocket (LBP), which was identified by X-ray crystallography as cholest-5-en-3beta-ol (cholesterol). Moreover, RORalpha transcriptional activity could be modulated by changes in intracellular cholesterol level or mutation of residues involved in cholesterol binding. These findings suggest that RORalpha could play a key role in the regulation of cholesterol homeostasis and thus represents an important drug target in cholesterol-related diseases.
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MESH Headings
- Cholesterol/metabolism
- Crystallography, X-Ray
- Humans
- Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology
- Ligands
- Lovastatin/pharmacology
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Protein Conformation
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Cytoplasmic and Nuclear/physiology
- Spectrometry, Mass, Electrospray Ionization
- Trans-Activators/chemistry
- Trans-Activators/metabolism
- Trans-Activators/physiology
- Transcription, Genetic/drug effects
- Transcription, Genetic/physiology
- Tumor Cells, Cultured
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Affiliation(s)
- Joerg A Kallen
- Central Technologies, Protein Structure Unit, Novartis Pharma AG, CH-4002 Basel, Switzerland.
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36
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Delerive P, Chin WW, Suen CS. Identification of Reverb(alpha) as a novel ROR(alpha) target gene. J Biol Chem 2002; 277:35013-8. [PMID: 12114512 DOI: 10.1074/jbc.m202979200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nuclear receptor superfamily comprises a large number of ligand-activated transcription factors that are involved in numerous biological processes such as cell proliferation, differentiation, and homeostasis. ROR(alpha) (NR1F1) and Reverb(alpha) (NR1D1) are two members of this family whose biological functions are largely unknown. In addition, no ligand has been yet identified for these two receptors; therefore, they are referred as orphan receptors. Here, we show that ROR(alpha) and Reverb(alpha) are expressed with a similar tissue distribution and are both induced during the differentiation of rat L6 myoblastic cells. Ectopic expression of ROR(alpha)1 in L6 cells significantly induces Reverb(alpha) expression as demonstrated by Northern blot analysis. Using reverse transcription-PCR to analyze Reverb(alpha) gene expression from staggerer mice, we found that there was a significant reduction of Reverb(alpha) mRNA in the skeletal muscle comparing it with the wild-type mice, which suggests that ROR(alpha) is involved in the regulation of Reverb(alpha) gene expression. Transient transfection assays using the Reverb(alpha) promoter demonstrate that ROR(alpha) regulates the Reverb(alpha) gene at the transcriptional level. Furthermore, mutagenesis experiments indicate that ROR(alpha) regulates Reverb(alpha) transcription via a monomeric ROR response element located in the Reverb(alpha) gene promoter. Electrophoretic mobility shift assays show that ROR(alpha) binds strongly to this site in a specific-manner. Finally, overexpression of GRIP-1/TIF-2, but not SRC-1, potentiates ROR(alpha)-stimulated Reverb(alpha) promoter activity in transient transfection experiments. Together, our results identify Reverb(alpha) as a novel target gene for ROR(alpha).
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Affiliation(s)
- Philippe Delerive
- Department of Gene Regulation, Bone and Inflammation Research, Eli Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
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37
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Chauvet C, Bois-Joyeux B, Danan JL. Retinoic acid receptor-related orphan receptor (ROR) alpha4 is the predominant isoform of the nuclear receptor RORalpha in the liver and is up-regulated by hypoxia in HepG2 human hepatoma cells. Biochem J 2002; 364:449-56. [PMID: 12023888 PMCID: PMC1222590 DOI: 10.1042/bj20011558] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The retinoic acid receptor-related orphan receptor alpha (RORalpha) is critically involved in many physiological functions in several organs. We find that the main RORalpha isoform in the mouse liver is the RORalpha4 isoform, in terms of both mRNA and protein levels, while the RORalpha1 isoform is less abundant. Because hypoxia is a major feature of liver physiology and pathology, we examined the effect of this stress on Rora gene expression and RORalpha transcriptional activity. HepG2 human hepatoma cells were cultured for 24 h under normoxia (20% O2) or hypoxia (10, 2, and 0.1% O2) and the abundance of the Rora transcripts measured by Northern blot and semi-quantitative RT-PCR. Hypoxic HepG2 cells contained more Rora mRNA than controls. This was also observed in rat hepatocytes in primary culture. Cobalt chloride and desferrioxamine also increased the amount of Rora mRNA in HepG2 cells. It is likely that these treatments increase the amount of the RORalpha4 protein in HepG2 cells as evidenced by Western blotting in the case of desferrioxamine. Transient transfection experiments indicated that hypoxia, cobalt chloride, and desferrioxamine all stimulate RORalpha transcriptional activity in HepG2 cells. Hence, we believe that RORalpha participates in the control of gene transcription in hepatic cells and modulates gene expression in response to hypoxic stress.
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MESH Headings
- Animals
- Base Sequence
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cell Hypoxia
- Cobalt/pharmacology
- DNA Primers
- Deferoxamine/pharmacology
- Gene Expression Regulation/drug effects
- Humans
- Liver/metabolism
- Mice
- Mice, Inbred C57BL
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Rats
- Rats, Wistar
- Receptor Protein-Tyrosine Kinases
- Receptor Tyrosine Kinase-like Orphan Receptors
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Cytoplasmic and Nuclear
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators
- Transcription, Genetic/drug effects
- Tumor Cells, Cultured
- Up-Regulation
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Affiliation(s)
- Caroline Chauvet
- Centre de Recherche sur l'Endocrinologie Moléculaire et le Développement, CNRS-UPR 9078, 9 rue Jules Hetzel, F92190 Meudon-Bellevue, France
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38
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Besnard S, Heymes C, Merval R, Rodriguez M, Galizzi JP, Boutin JA, Mariani J, Tedgui A. Expression and regulation of the nuclear receptor RORalpha in human vascular cells. FEBS Lett 2002; 511:36-40. [PMID: 11821045 DOI: 10.1016/s0014-5793(01)03275-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Retinoic acid receptor-related orphan receptor alpha (RORalpha) is a member of the nuclear receptor superfamily. Using RT-PCR, RORalpha mRNA was identified in human aortic smooth muscle cells (hASMC), endothelial cells (EC), as well as in human mammary arteries and atherosclerotic plaques. We found a predominant expression of RORalpha1 in hASMC, and RORalpha4 in EC. RORalpha2 and RORalpha3 were not detected. In arteries, RORalpha4 was predominant compared with RORalpha1. In atherosclerotic plaques, RORalpha expression was significantly decreased. In hASMC stimulated with cytokines, RORalpha expression was increased by 2.5-fold. RORalpha mRNA was also significantly increased (approximately 2-fold) in hASMC and EC cultured under hypoxia.
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MESH Headings
- Aorta
- Arteriosclerosis/genetics
- Arteriosclerosis/metabolism
- Carotid Stenosis/genetics
- Carotid Stenosis/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Gene Expression Profiling
- Gene Expression Regulation/drug effects
- Humans
- Hypoxia/genetics
- Hypoxia/metabolism
- Interleukin-1/pharmacology
- Lipopolysaccharides/pharmacology
- Mammary Arteries/cytology
- Mammary Arteries/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Oxygen/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Tumor Necrosis Factor-alpha/pharmacology
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39
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Jetten AM, Kurebayashi S, Ueda E. The ROR nuclear orphan receptor subfamily: critical regulators of multiple biological processes. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 69:205-47. [PMID: 11550795 DOI: 10.1016/s0079-6603(01)69048-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The nuclear receptor superfamily, a group of structurally related, ligand-dependent transcription factors, includes a large number of orphan receptors for which no ligand has yet been identified. These proteins function as key regulators of many physiological processes that occur during embryonic development and in the adult. The retinoid-related orphan receptors (RORs) alpha, beta, and gamma comprise one nuclear orphan receptor gene subfamily. RORs exhibit a modular structure that is characteristic for nuclear receptors; the DNA-binding domain is highly conserved and the ligand-binding domain is moderately conserved among RORs. By a combination of alternative promoter usage and exon splicing, each ROR gene generates several isoforms that differ only in their amino terminus. RORs bind as monomers to specific ROR response elements (ROREs) consisting of the consensus core motif AGGTCA preceded by a 5-bp A/T-rich sequence. RORE-dependent transcriptional activation by RORs is cell type-specific and mediated through interactions with nuclear cofactors. RORs have been shown to interact with certain corepressors as well as coactivators, suggesting that RORs are not constitutively active but that their activity is under some regulatory control. RORs likely can assume at least two different conformations: a repressive state, which allows interaction with corepressor complexes, and an active state, which promotes binding of coactivator complexes. Whether the transition between these two states is regulated by ligand binding and/or by phosphorylation remains to be determined. Ca2+/calmodulin-dependent kinase IV (CaMKIV) can dramatically enhance ROR-mediated transcriptional activation. This stimulation involves CaMKIV-mediated phosphorylation not of RORs, but likely of specific nuclear cofactors that interact with RORs. RORalpha is widely expressed. In the cerebellum, its expression is limited to the Purkinje cells. RORalpha-/- mice and the natural RORalpha-deficient staggerer mice exhibit severe cerebellar ataxia due to a defect in Purkinje cell development. In addition, these mice have thin long bones, suggesting a role for RORalpha in bone metabolism, and develop severe atherosclerosis when placed on a high-fat diet. Expression of RORbeta is very restricted. RORbeta is highly expressed in different parts of the neurophotoendocrine system, the pineal gland, the retina, and suprachiasmatic nuclei, suggesting a role in the control of circadian rhythm. This is supported by observations showing alterations in circadian behavior in RORbeta-/- mice. RORgamma, which is most highly expressed in the thymus, plays an important role in thymopoiesis. Thymocytes from RORgamma-/- mice undergo accelerated apoptosis. The induction of apoptosis is, at least in part, due to a down-regulation of the expression of the antiapoptotic gene Bcl-XL. In addition to the thynic phenotype, RORgamma-/- mice lack lymph nodes, indicating that RORgamma is essential for lymph node organogenesis. Overexpression of RORgamma has been shown to inhibit T cell receptor-mediated apoptosis in T cell hybridomas and to repress the induction of Fas-ligand and interleukin 2. These studies demonstrate that RORs play critical roles in the regulation of a variety of physiological processes. Further characterization of the mechanisms of action of RORs will not only lead to the identification of ROR target genes and provide additional insight into their normal physiological functions, but will also determine their roles in disease.
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MESH Headings
- Amino Acid Sequence
- Animals
- Apoptosis
- Cloning, Molecular
- Gene Expression
- Hematopoiesis
- Humans
- Ligands
- Mice
- Mice, Knockout
- Molecular Sequence Data
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Nuclear Receptor Subfamily 1, Group F, Member 2
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Phenotype
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/physiology
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid
- Receptors, Thyroid Hormone
- Sequence Homology, Amino Acid
- Trans-Activators/chemistry
- Trans-Activators/genetics
- Trans-Activators/physiology
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Affiliation(s)
- A M Jetten
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, North Carolina 27709, USA.
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Dai J, Ram PT, Yuan L, Spriggs LL, Hill SM. Transcriptional repression of RORalpha activity in human breast cancer cells by melatonin. Mol Cell Endocrinol 2001; 176:111-20. [PMID: 11369450 DOI: 10.1016/s0303-7207(01)00449-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melatonin has repeatedly been shown to inhibit the proliferation of MCF-7 human breast cancer cells. Previous reports suggest that the actions of melatonin can be mediated either through G-protein coupled membrane receptors or via retinoid orphan receptors (RORalphas). In this study, we demonstrated the expression of RORalpha2, 3, and 4 transcripts in MCF-7 cells. These cells exhibited a high basal level of RORalpha transcriptional activity, which was further stimulated by serum. In the presence of serum, RORalpha transactivation and DNA-binding activity was repressed by melatonin even though melatonin had no effect on RORalpha protein levels. We found that RORalpha transcriptional activity in MCF-7 cells was regulated by modulators of the Ca2+/CaM signaling pathway. Given that melatonin has been reported to modulate the Ca2+/CaM signaling pathway in other tissues, our data indicate that melatonin may affect RORalpha transcriptional activity, expression of RORalpha regulated genes, and even breast cancer cell proliferation via modulation of the Ca2+/CaM signaling pathway.
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MESH Headings
- Antioxidants/pharmacology
- Blotting, Western
- Breast Neoplasms/enzymology
- Breast Neoplasms/genetics
- Calcium Signaling/drug effects
- Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Calmodulin/antagonists & inhibitors
- Calmodulin/metabolism
- DNA/genetics
- DNA/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Female
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Melatonin/pharmacology
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Protein Binding/drug effects
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription, Genetic/drug effects
- Transcriptional Activation/drug effects
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- J Dai
- Department of Structural and Cellular Biology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA
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41
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Eystathioy T, Swevers L, Iatrou K. The orphan nuclear receptor BmHR3A of Bombyx mori: hormonal control, ovarian expression and functional properties. Mech Dev 2001; 103:107-15. [PMID: 11335116 DOI: 10.1016/s0925-4773(01)00335-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Ovarian development in the domesticated silkmoth, Bombyx mori, is induced by the molting hormone 20-hydroxy-ecdysone (20E) shortly after larval-pupal ecdysis. Studies of the ecdysone response in Drosophila and other insects have shown that 20E exerts its effects initially by the induction of a small number of early genes, including the orphan nuclear receptors HR3, that transduce and amplify the hormone signal. Here we show that the silkmoth orphan receptor BmHR3A acts in the 20E-induced regulatory cascade in the ovary during pupal and pharate adult development in a manner different than that observed in the classical ecdysone regulatory hierarchy in Drosophila salivary glands at the end of the third instar. While other isoforms of BmHR3 are induced as early gene products in the ecdysone response, BmHR3A is induced 2 days after 20E administration in the silkmoth ovary and, thus, behaves as late product. The period of accumulation of BmHR3A in ovarian follicular cells occurs during vitellogenesis and coincides with the period of transcriptional expression of the ESP (egg-specific protein) gene, whose product constitutes a major component of the egg yolk, while it is reciprocal to the period of expression of BmGATAbeta, a gene encoding a regulator of late chorion gene expression. Bandshift experiments demonstrate that BmHR3A binds specifically to RORE (Retinoic acid-related Orphan receptor Response Element)-like sequences in the promoters of both genes, thus suggesting a direct role for BmHR3A in regulating the expression of BmGATAbeta and ESP genes during vitellogenesis. Finally, we show that BmHR3A functions as a constitutive transcriptional activator in a B. mori derived cell line. We propose that BmHR3A may function as a regulator of vitellogenesis in the silkmoth ovary.
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Affiliation(s)
- T Eystathioy
- Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive N.W., Calgary, AB T2N 4N1, Canada
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42
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Hauksdóttir H, Privalsky ML. DNA recognition by the aberrant retinoic acid receptors implicated in human acute promyelocytic leukemia. CELL GROWTH & DIFFERENTIATION : THE MOLECULAR BIOLOGY JOURNAL OF THE AMERICAN ASSOCIATION FOR CANCER RESEARCH 2001; 12:85-98. [PMID: 11243468 PMCID: PMC2712924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Human acute promyelocytic leukemias (APLs) are associated with chromosomal translocations that replace the NH2 terminus of wild-type retinoic acid receptor (RAR) alpha with portions of the promyelocytic leukemia protein (PML) or promyelocytic leukemia zinc-finger protein (PLZF). The wild-type RARalpha readily forms heterodimers with the retinoid X receptors (RXRs), and these RAR/RXR heterodimers appear to be the principal mediators of retinoid signaling in normal cells. In contrast, PML-RARalpha and PLZF-RARa display an enhanced ability to form homodimers, and this enhanced homodimer formation is believed to contribute to the neoplastic properties of these chimeric oncoproteins. We report here that the DNA recognition specificity of the RXRalpha/RARa heterodimer, which is presumed to be the dominant receptor species in normal cells, differs from that of the PML-RARalpha and PLZF-RARalpha homodimers, which are thought to prevail in the oncogenic cell. We suggest that differences in target gene recognition by the normal and oncogenic RARalpha proteins may contribute to the leukemogenic phenotype.
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Affiliation(s)
| | - Martin L. Privalsky
- To whom requests for reprints should be addressed, at Section of Microbiology, Division of Biological Sciences, University of California at Davis, One Shields Avenue, Davis, CA 95616. Phone: (530) 752-3013; Fax: (530) 752-9014; E-mail:
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43
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Delerive P, Monté D, Dubois G, Trottein F, Fruchart-Najib J, Mariani J, Fruchart JC, Staels B. The orphan nuclear receptor ROR alpha is a negative regulator of the inflammatory response. EMBO Rep 2001; 2:42-8. [PMID: 11252722 PMCID: PMC1083804 DOI: 10.1093/embo-reports/kve007] [Citation(s) in RCA: 236] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Retinoid-related orphan receptor alpha (ROR alpha) (NR1F1) is a member of the nuclear receptor superfamily whose biological functions are largely unknown. Since staggerer mice, which carry a deletion in the ROR alpha gene, suffer from immune abnormalities, we generated an adenovirus encoding ROR alpha1 to investigate its potential role in control of the inflammatory response. We demonstrated that ROR alpha is expressed in human primary smooth-muscle cells and that ectopic expression of ROR alpha1 inhibits TNFalpha-induced IL-6, IL-8 and COX-2 expression in these cells. ROR alpha1 negatively interferes with the NF-kappaB signalling pathway by reducing p65 translocation as demonstrated by western blotting, immunostaining and electrophoretic mobility shift assays. This action of ROR alpha1 on NF-kappaB is associated with the induction of IkappaB alpha, the major inhibitory protein of the NF-kappaB signalling pathway, whose expression was found to be transcriptionally upregulated by ROR alpha1 via a ROR response element in the IkappaB alpha promoter. Taken together, these data identify ROR alpha1 as a potential target in the treatment of chronic inflammatory diseases, including atherosclerosis and rheumatoid arthritis.
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MESH Headings
- Adenoviridae/genetics
- Blotting, Western
- Calcium-Binding Proteins
- Cell Nucleus/metabolism
- Cells, Cultured
- Cyclooxygenase 2
- DNA, Complementary/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Humans
- I-kappa B Proteins
- Immunoblotting
- Immunohistochemistry
- Inflammation/metabolism
- Interleukin-6/metabolism
- Interleukin-8/metabolism
- Isoenzymes/metabolism
- Membrane Glycoproteins/metabolism
- Membrane Proteins
- Muscle, Smooth/cytology
- Muscle, Smooth/metabolism
- Muscle, Smooth, Vascular/metabolism
- NF-KappaB Inhibitor alpha
- NF-kappa B/metabolism
- Nerve Tissue Proteins/metabolism
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Plasmids/metabolism
- Promoter Regions, Genetic
- Prostaglandin-Endoperoxide Synthases/metabolism
- Protein Binding
- RNA/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Cytoplasmic and Nuclear/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Synaptotagmin I
- Synaptotagmins
- Time Factors
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Trans-Activators/physiology
- Transcription, Genetic
- Transfection
- Tumor Necrosis Factor-alpha/metabolism
- Up-Regulation
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Affiliation(s)
- P Delerive
- INSERM U325, Département d'Athérosclérose, Institut Pasteur de Lille, France
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Gawlas K, Stunnenberg HG. Differential binding and transcriptional behaviour of two highly related orphan receptors, ROR alpha(4) and ROR beta(1). BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1494:236-41. [PMID: 11121580 DOI: 10.1016/s0167-4781(00)00237-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Nuclear receptors are ligand-inducible transcription factors that can be classified into two major groups according to their DNA-binding properties. Members of the first group bind to DNA as dimers, either homo- or heterodimers; members of the second group are also able to bind as monomers. While the first group has been extensively studied biochemically, very little is known about nuclear receptors that bind and act as monomers. In this study, we compared the binding and transcriptional behaviour of ROR alpha (NR1F1) and ROR beta (NR1F2), two representatives of the subgroup of monomer-binding receptors. We show that although they are highly related in their amino acid structures, they display remarkably different binding behaviours. Furthermore, we provide evidence that ROR beta can efficiently activate transcription in vitro as a monomer.
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Affiliation(s)
- K Gawlas
- Department of Molecular Biology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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45
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Wirtanen L, Séguin C. Cloning of cDNAs encoding retinoic acid receptors RAR gamma 1, RAR gamma 2, and a new splicing variant, RAR gamma 3, from Aambystoma mexicanum and characterization of their expression during early development. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1492:81-93. [PMID: 11004482 DOI: 10.1016/s0167-4781(00)00081-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To analyze retinoic acid (RA) receptor (RAR) expression during early development in the urodele embryo, we have isolated cDNAs for four members of the axolotl (Ambystoma mexicanum) RAR family, namely RAR alpha (NR1B1), aRAR gamma 1 (NR1B3a), aRAR gamma 2 (NR1B3b), and a new splicing variant of aRAR gamma 2, aRAR gamma 3 (NR1B3c), which contains an insertion of five hydrophobic amino acids in the C-terminal region of the DNA binding domain. The temporal expression pattern of the RAR gamma isoforms was established by RT-PCR using total RNA from embryos of different stages. The expression of aRAR gamma 2 coincides with neurulation and is enhanced in the extremities of the embryo's anteroposterior axis. The aRAR gamma 3 is specifically expressed during gastrulation and early neurulation, whereas aRAR gamma 1 is expressed later during organogenesis. Global aRAR gamma 2 mRNA levels, as well as their spatio-temporal expression pattern in the neurula, were not affected by treatment with RA. These results show that several RARs are expressed in the axolotl embryo during early development, and reveal the existence of a new RAR gamma variant.
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Affiliation(s)
- L Wirtanen
- Centre de Recherche en Cancérologie de l'Université Laval, Québec, Québec, Canada
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46
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Chomez P, Neveu I, Mansén A, Kiesler E, Larsson L, Vennström B, Arenas E. Increased cell death and delayed development in the cerebellum of mice lacking the rev-erbA(alpha) orphan receptor. Development 2000; 127:1489-98. [PMID: 10704394 DOI: 10.1242/dev.127.7.1489] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The rev-erbA(alpha) gene, belonging to the steroid receptor superfamily of transcription factors, is highly conserved during evolution but little is known so far about its functions in development or in adult physiology. Here, we describe genetically altered mice lacking the rev-erbA(alpha) gene. These animals do not show any obvious phenotype in either fat tissue or skeletal muscle, despite the known regulation of rev-erbA(alpha) expression during adipocyte and myotube differentiation in vitro. However, during the second week of life, the cerebellum of rev-erbA(alpha) mutants presents several unexpected abnormalities, such as alterations in the development of Purkinje cells, delay in the proliferation and migration of granule cells from the external granule cell layer and increased apoptosis of neurons in the internal granule cell layer. Interestingly, the expression pattern of rev-erbA(alpha) suggests that the abnormalities observed in the external granule cell layer could be secondary to Purkinje cell alterations. Taken together, our data underline the importance of rev-erbA(alpha)expression for the appropriate balance of transcriptional activators and repressors during postnatal cerebellar development.
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Affiliation(s)
- P Chomez
- Department of Cell and Molecular Biology and Department of Medical Biochemistry and Biophysics, Karolinska Institute, S-171 77 Stockholm, Sweden
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47
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Kapitskaya MZ, Li C, Miura K, Segraves W, Raikhel AS. Expression of the early-late gene encoding the nuclear receptor HR3 suggests its involvement in regulating the vitellogenic response to ecdysone in the adult mosquito. Mol Cell Endocrinol 2000; 160:25-37. [PMID: 10715536 DOI: 10.1016/s0303-7207(99)00253-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The insect steroid hormone, 20-hydroxyecdysone (20E), is a key factor controlling critical developmental events of embryogenesis, larval molting, metamorphosis, and, in some insects, reproduction. We are interested in understanding the molecular basis of the steroid hormone ecdysone action in insect egg development. The yellow fever mosquito, Aedes aegypti, in addition to being an important vector of human diseases, represents an outstanding model for studying molecular mechanisms underlying egg maturation due to stringently controlled, blood meal-activated reproductive events in this insect. To elucidate the genetic regulatory hierarchy controlling the reproductive ecdysone response, we have investigated ecdysone-regulated gene expression in vitellogenic mosquito ovaries and fat bodies. We have previously demonstrated the conservation of a primary ecdysone-triggered regulatory hierarchy, implicated in development of immature stages of Drosophila, represented by the ecdysone receptor/Ultraspiracle complex and an early gene E75 during the reproductive ecdysone response (Wang, S.-F., Miura, K., Miksicek, R.J., Segraves, W.A., Raikhel, A.S., 1998. DNA binding and transactivation characteristics of the mosquito ecdysone receptor - Ultraspiracle complex. J. Biol. Chem. 273, 27531-27540; Pierceall, W. E., Li, C., Biran, A., Miura, K., Raikhel, A.S., Segraves, W.A., 1999. E75 expression in mosquito ovary and fat body suggests reiterative use of ecdysone-regulated hierarchies in development and reproduction. Mol. Cell. Endocrinol. 150, 73-89). The present paper demonstrates that conservation of the factors involved in the ecdysone-responsive genetic hierarchy regulating female reproduction extends beyond the early genes. Here, we identify AHR3, a highly conserved homologue of the Drosophila HR3 early-late ecdysone-inducible gene in the mosquito. We show that AHR3 is expressed in both vitellogenic tissues of the female mosquito, the fat body and the ovary. The expression of AHR3 correlates with the ecdysteroid titer, reaching a peak at 24 h after a blood meal. Moreover, in vitro fat body culture experiments demonstrate that the kinetics and dose response of AHR3 to 20-hydroxyecdysone (20E), an active ecdysteroid in the mosquito, is similar to those of the late vitellogenic genes rather than the early E75 gene. However, as shown for other early and early-late genes, the 20E activation of AHR3 is not inhibited by the presence of cycloheximide, a protein synthesis inhibitor. Taken together, these findings strongly suggest AHR3 involvement in regulating the vitellogenic response to ecdysone in the adult mosquito.
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MESH Headings
- Aedes/genetics
- Aedes/growth & development
- Aedes/physiology
- Amino Acid Sequence
- Animals
- Base Sequence
- Cloning, Molecular
- Conserved Sequence
- DNA Primers/genetics
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Ecdysterone/pharmacology
- Fat Body/metabolism
- Female
- Gene Expression Regulation, Developmental/drug effects
- Genes, Insect/drug effects
- Humans
- In Vitro Techniques
- Insect Proteins/genetics
- Insect Proteins/physiology
- Molecular Sequence Data
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Sequence Homology, Amino Acid
- Vitellogenesis/drug effects
- Vitellogenesis/genetics
- Vitellogenesis/physiology
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Affiliation(s)
- M Z Kapitskaya
- Program in Genetics and Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
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Kane CD, Means AR. Activation of orphan receptor-mediated transcription by Ca(2+)/calmodulin-dependent protein kinase IV. EMBO J 2000; 19:691-701. [PMID: 10675338 PMCID: PMC305607 DOI: 10.1093/emboj/19.4.691] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/1999] [Revised: 11/17/1999] [Accepted: 12/07/1999] [Indexed: 11/14/2022] Open
Abstract
Retinoid-related receptor alpha (RORalpha) is an orphan nuclear receptor that constitutively activates transcription from its cognate response element. We show that RORalpha is Ca(2+ )responsive, and a Ca(2+)/calmodulin-independent form of Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) potentiates RORalpha-dependent transcription 20- to 30-fold. Other orphan receptors including RORalpha2, RORgamma and COUP-TFI are also potentiated by CaMKIV. Transcriptional activation by CaMKIV is orphan receptor selective and does not occur with either the thyroid hormone or estrogen receptor. CaMKIV does not phosphorylate RORalpha or its ligand-binding domain (LBD) in vitro, although the LBD is essential for transactivation. Therefore, the RORalpha LBD was used in the mammalian two-hybrid assay to identify a single class of small peptide molecules containing LXXLL motifs that interacted with greater affinity in the presence of CaMKIV. This class of peptides antagonized activation of orphan receptor-mediated transcription by CaMKIV. These studies demonstrate a pivotal role for CaMKIV in the regulation of orphan receptor-mediated transcription.
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Affiliation(s)
- C D Kane
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, PO Box 3813, Durham, NC 27710, USA
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49
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Affiliation(s)
- V Giguère
- Molecular Oncology Group, McGill University Health Centre.
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50
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Atkins GB, Hu X, Guenther MG, Rachez C, Freedman LP, Lazar MA. Coactivators for the orphan nuclear receptor RORalpha. Mol Endocrinol 1999; 13:1550-7. [PMID: 10478845 DOI: 10.1210/mend.13.9.0343] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A mutation in the nuclear orphan receptor RORalpha results in a severe impairment of cerebellar development by unknown mechanisms. We have shown previously that RORalpha contains a strong constitutive activation domain in its C terminus. We therefore searched for mammalian RORalpha coactivators using the minimal activation domain as bait in a two-hybrid screen. Several known and putative coactivators were isolated, including glucocorticoid receptor-interacting protein-1 (GRIP-1) and peroxisome proliferator-activated receptor (PPAR)-binding protein (PBP/TRAP220/DRIP205). These interactions were confirmed in vitro and require the intact activation domain of RORalpha although different requirements for interaction with GRIP-1 and PBP were detected. Even in the absence of exogenous ligand, RORalpha interacts with a complex or complexes of endogenous proteins, similar to those that bind to ligand-occupied thyroid hormone and vitamin D receptors. Both PBP and GRIP-1 were shown to be present in these complexes. Thus we have identified several potential RORalpha coactivators that, in contrast to the interactions with hormone receptors, interact with RORalpha in yeast, in bacterial extracts, and in mammalian cells in vivo and in vitro in the absence of exogenous ligand. GRIP-1 functioned as a coactivator for the RORalpha both in yeast and in mammalian cells. Thus, GRIP-1 is the first proven coactivator for RORalpha.
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Affiliation(s)
- G B Atkins
- Department of Medicine, The Penn Diabetes Center, University of Pennsylvania School of Medicine, Philadelphia 19104-6149, USA
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