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Fontaine R, Royan MR, von Krogh K, Weltzien FA, Baker DM. Direct and Indirect Effects of Sex Steroids on Gonadotrope Cell Plasticity in the Teleost Fish Pituitary. Front Endocrinol (Lausanne) 2020; 11:605068. [PMID: 33365013 PMCID: PMC7750530 DOI: 10.3389/fendo.2020.605068] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/12/2020] [Indexed: 12/26/2022] Open
Abstract
The pituitary gland controls many important physiological processes in vertebrates, including growth, homeostasis, and reproduction. As in mammals, the teleost pituitary exhibits a high degree of plasticity. This plasticity permits changes in hormone production and secretion necessary to meet the fluctuating demands over the life of an animal. Pituitary plasticity is achieved at both cellular and population levels. At the cellular level, hormone synthesis and release can be regulated via changes in cell composition to modulate both sensitivity and response to different signals. At the cell population level, the number of cells producing a given hormone can change due to proliferation, differentiation of progenitor cells, or transdifferentiation of specific cell types. Gonadotropes, which play an important role in the control of reproduction, have been intensively investigated during the last decades and found to display plasticity. To ensure appropriate endocrine function, gonadotropes rely on external and internal signals integrated at the brain level or by the gonadotropes themselves. One important group of internal signals is the sex steroids, produced mainly by the gonadal steroidogenic cells. Sex steroids have been shown to exert complex effects on the teleost pituitary, with differential effects depending on the species investigated, physiological status or sex of the animal, and dose or method of administration. This review summarizes current knowledge of the effects of sex steroids (androgens and estrogens) on gonadotrope cell plasticity in teleost anterior pituitary, discriminating direct from indirect effects.
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Affiliation(s)
- Romain Fontaine
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Muhammad Rahmad Royan
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Kristine von Krogh
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Finn-Arne Weltzien
- Physiology Unit, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Dianne M. Baker
- Department of Biological Sciences, University of Mary Washington, Fredericksburg, VA, United States
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Amenyogbe E, Chen G, Wang Z, Lu X, Lin M, Lin AY. A Review on Sex Steroid Hormone Estrogen Receptors in Mammals and Fish. Int J Endocrinol 2020; 2020:5386193. [PMID: 32089683 PMCID: PMC7029290 DOI: 10.1155/2020/5386193] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/04/2019] [Accepted: 11/19/2019] [Indexed: 12/26/2022] Open
Abstract
Steroid hormones play essential roles in the reproductive biology of vertebrates. Estrogen exercises its effect through estrogen receptors and is not only a female reproductive hormone but acts virtually in all vertebrates, including fish, and is involved in the physiological and pathological states in all males and females. Estrogen has been implicated in mandible conservation and circulatory and central nervous systems as well as the reproductive system. This review intended to understand the structure, function, binding affinities, and activations of estrogens and estrogen receptors and to discuss the understanding of the role of sex steroid hormone estrogen receptors in mammals and fish.
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Affiliation(s)
- Eric Amenyogbe
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
| | - Gang Chen
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
| | - Zhongliang Wang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
| | - Xiaoying Lu
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
| | - Mingde Lin
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
| | - Ai Ying Lin
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524025, China
- Guangdong Provincial Key Laboratory of Aquaculture in the South China Sea for Aquatic Economic Animal of Guangdong Higher Education Institutes, Laboratory of Fish Aquaculture, Zhanjiang 524025, China
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He Y, Folkerts EJ, Zhang Y, Martin JW, Alessi DS, Goss GG. Effects on Biotransformation, Oxidative Stress, and Endocrine Disruption in Rainbow Trout (Oncorhynchus mykiss) Exposed to Hydraulic Fracturing Flowback and Produced Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:940-947. [PMID: 27973770 DOI: 10.1021/acs.est.6b04695] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of hydraulic fracturing (HF) flowback and produced water (HF-FPW), a complex saline mixture of injected HF fluids and deep formation water that return to the surface, was examined in rainbow trout (Oncorhynchus mykiss). Exposure to HF-FPWs resulted in significant induction of ethoxyresorufin-O-deethylase (EROD) activity in both liver and gill tissues. Increased lipid peroxidation via oxidative stress was also detected by thiobarbituric acid reactive substances (TBARS) assay. The mRNA expressions of a battery of genes related to biotransformation, oxidative stress, and endocrine disruption were also measured using quantitative real-time polymerase chain reaction (Q-RT-PCR). The increased expression of cyp1a (2.49 ± 0.28-fold), udpgt (2.01 ± 0.31-fold), sod (1.67 ± 0.09-fold), and gpx (1.58 ± 0.10-fold) in raw sample exposure group (7.5%) indicated elevated metabolic enzyme activity, likely through the aryl hydrocarbon receptor pathway, and generation of reactive oxygen species. In addition, the elevated vtg and era2 expression demonstrated endocrine disrupting potential exerted by HF-FPW in rainbow trout. The overall results suggested HF-FPW could cause significant adverse effects on fish, and the organic contents might play the major role in its toxicity. Future studies are needed to help fully determine the toxic mechanism(s) of HF-FPW on freshwater fish, and aid in establishing monitoring, treatment, and remediation protocols for HF-FPW.
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Affiliation(s)
- Yuhe He
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
| | - Erik J Folkerts
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
| | - Yifeng Zhang
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
| | - Jonathan W Martin
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
| | - Daniel S Alessi
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
| | - Greg G Goss
- Department of Biological Sciences, ‡Department of Laboratory Medicine and Pathology and §Department of Earth and Atmospheric Sciences, University of Alberta , Edmonton, Alberta Canada , T6G 2E9
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Cocci P, Mozzicafreddo M, Angeletti M, Mosconi G, Palermo FA. In silico prediction and in vivo analysis of antiestrogenic potential of 2-isopropylthioxanthone (2-ITX) in juvenile goldfish (Carassius auratus). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 133:202-210. [PMID: 27454205 DOI: 10.1016/j.ecoenv.2016.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 07/12/2016] [Accepted: 07/15/2016] [Indexed: 06/06/2023]
Abstract
Previous studies have shown both anti-estrogenic and anti-androgenic activities of 2-isopropylthioxanthone (2-ITX), a well known food contaminant, in in vitro assays. However, no data are available on the anti-estrogenic potentials and risks of 2-ITX in aquatic organisms. This work evaluated the potential endocrine disrupting effects of 2-ITX at the level of estrogen receptor (ER) signaling cascade using juvenile goldfish (Carassius auratus) as model. Firstly, we investigated the ligand binding efficiency of 2-ITX to the ligand binding domains (LBD) of goldfish ER subtypes using a molecular docking approach. Secondly, we assessed the effects of 2-ITX on E2-induced hepatic expression of ERα1, ERβ1, ERβ2, and vitellogenin (VTG) in vivo. Crosstalk between ER-VTG and aryl hydrocarbon receptor 2 (AhR2)-cytochrome P4501A (CYP1A) was also investigated. Fish were injected with increasing doses of 2-ITX ranging from 2 to 10µg/g BW, and results were compared to the effect of tamoxifen, a well-known ER modulator. We observed that compared to ERβ, the interaction potentials of 2-ITX to goldfish ERα1 LBD was more stable in the inactive receptor conformation. The in silico docking simulation analysis also revealed that 2-ITX acted as agonist for the goldfish AhR2 LBDs suggesting the ability of this compound to activate the cross-talk between the ERα- and AhR-signaling pathways. In vivo experiments confirm in silico simulation predictions demonstrating that 2-ITX reduced the estrogenicity of E2 at both transcriptional and post-transcriptional levels, indicating a clear anti-estrogenic effect. Co-exposure of E2 and 2-ITX also resulted in a significant decrease of CYP1A gene expression with respect to 2-ITX alone. Results from these studies collectively revealed that the antiestrogenic property of 2-ITX can be ascribed to a combination of effects on multiple signaling pathways suggesting the potential for this environmental contaminant to affect the hormonal control of reproductive processes in fish.
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Affiliation(s)
- Paolo Cocci
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy.
| | - Matteo Mozzicafreddo
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Gilberto Mosconi
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
| | - Francesco Alessandro Palermo
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III Da Varano, I-62032 Camerino, MC, Italy
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Cotter KA, Nacci D, Champlin D, Yeo AT, Gilmore TD, Callard GV. Adaptive Significance of ERα Splice Variants in Killifish (Fundulus heteroclitus) Resident in an Estrogenic Environment. Endocrinology 2016; 157:2294-308. [PMID: 27070100 DOI: 10.1210/en.2016-1052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The possibility that chronic, multigenerational exposure to environmental estrogens selects for adaptive hormone-response phenotypes is a critical unanswered question. Embryos/larvae of killifish from an estrogenic-polluted environment (New Bedford Harbor, MA [NBH]) compared with those from a reference site overexpress estrogen receptor alpha (ERα) mRNA but are hyporesponsive to estradiol. Analysis of ERα mRNAs in the two populations revealed differences in splicing of the gene encoding ERα (esr1). Here we tested the transactivation functions of four differentially expressed ERα mRNAs and tracked their association with the hyporesponsive phenotype for three generations after transfer of NBH parents to a clean environment. Deletion variants ERαΔ6 and ERαΔ6-8 were specific to NBH killifish, had dominant negative functions in an in vitro reporter assay, and were heritable. Morpholino-mediated induction of ERαΔ6 mRNA in zebrafish embryos verified its role as a dominant negative ER on natural estrogen-responsive promoters. Alternate long (ERαL) and short (ERαS) 5'-variants were similar transcriptionally but differed in estrogen responsiveness (ERαS ≫ ERαL). ERαS accounted for high total ERα expression in first generation (F1) NBH embryos/larvae but this trait was abolished by transfer to clean water. By contrast, the hyporesponsive phenotype of F1 NBH embryos/larvae persisted after long-term laboratory holding but reverted to a normal or hyper-responsive phenotype after two or three generations, suggesting the acquisition of physiological or biochemical traits that compensate for ongoing expression of negative-acting ERαΔ6 and ERαΔ6-8 isoforms. We conclude that a heritable change in the pattern of alternative splicing of ERα pre-mRNA is part of a genetic adaptive response to estrogens in a polluted environment.
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Affiliation(s)
- Kellie A Cotter
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
| | - Diane Nacci
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
| | - Denise Champlin
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
| | - Alan T Yeo
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
| | - Thomas D Gilmore
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
| | - Gloria V Callard
- Department of Biology (K.A.C., A.T.Y., T.D.G., G.V.C.), Boston University, Boston, Massachusetts 02215; and Office of Research and Development (D.N., D.C.), National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, Rhode Island 02882
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Marlatt VL, Sherrard R, Kennedy CJ, Elphick JR, Martyniuk CJ. Application of molecular endpoints in early life stage salmonid environmental biomonitoring. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 173:178-191. [PMID: 26874677 DOI: 10.1016/j.aquatox.2016.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/16/2016] [Accepted: 01/20/2016] [Indexed: 06/05/2023]
Abstract
Molecular endpoints can enhance existing whole animal bioassays by more fully characterizing the biological impacts of aquatic pollutants. Laboratory and field studies were used to examine the utility of adopting molecular endpoints for a well-developed in situ early life stage (eyed embryo to onset of swim-up fry) salmonid bioassay to improve diagnostic assessments of water quality in the field. Coastal cutthroat trout (Oncorhynchus clarki clarki) were exposed in the laboratory to the model metal (zinc, 40μg/L) and the polycyclic aromatic hydrocarbon (pyrene, 100μg/L) in water to examine the resulting early life stage salmonid responses. In situ field exposures and bioassays were conducted in parallel to evaluate the water quality of three urban streams in British Columbia (two sites with anthropogenic inputs and one reference site). The endpoints measured in swim-up fry included survival, deformities, growth (weight and length), vitellogenin (vtg) and metallothionein (Mt) protein levels, and hepatic gene expression (e.g., metallothioneins [mta and mtb], endocrine biomarkers [vtg and estrogen receptors, esr] and xenobiotic-metabolizing enzymes [cytochrome P450 1A3, cyp1a3 and glutathione transferases, gstk]). No effects were observed in the zinc treatment, however exposure of swim-up fry to pyrene resulted in decreased survival, deformities and increased estrogen receptor alpha (er1) mRNA levels. In the field exposures, xenobiotic-metabolizing enzymes (cyp1a3, gstk) and zinc transporter (zntBigM103) mRNA were significantly increased in swim-up fry deployed at the sites with more anthropogenic inputs compared to the reference site. Cluster analysis revealed that gene expression profiles in individuals from the streams receiving anthropogenic inputs were more similar to each other than to the reference site. Collectively, the results obtained in this study suggest that molecular endpoints may be useful, and potentially more sensitive, indicators of site-specific contamination in real-world, complex exposure scenarios in addition to whole body morphometric and physiological measures.
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Affiliation(s)
- Vicki L Marlatt
- Department of Biological Sciences, Simon, Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada.
| | - Ryan Sherrard
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada
| | - Chris J Kennedy
- Department of Biological Sciences, Simon, Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada; Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada; Nautilus Environmental, 8664 Commerce Court, Imperial Square Lake City, Burnaby, British Columbia V5A 4N71, Canada
| | - James R Elphick
- Nautilus Environmental, 8664 Commerce Court, Imperial Square Lake City, Burnaby, British Columbia V5A 4N71, Canada
| | - Christopher J Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada
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Li H, Wang T, Xu C, Wang D, Ren J, Li Y, Tian Y, Wang Y, Jiao Y, Kang X, Liu X. Transcriptome profile of liver at different physiological stages reveals potential mode for lipid metabolism in laying hens. BMC Genomics 2015; 16:763. [PMID: 26452545 PMCID: PMC4600267 DOI: 10.1186/s12864-015-1943-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/21/2015] [Indexed: 11/24/2022] Open
Abstract
Background Liver is an important metabolic organ that plays a critical role in lipid synthesis, degradation, and transport; however, the molecular regulatory mechanisms of lipid metabolism remain unclear in chicken. In this study, RNA-Seq technology was used to investigate differences in expression profiles of hepatic lipid metabolism-related genes and associated pathways between juvenile and laying hens. The study aimed to broaden the understanding of liver lipid metabolism in chicken, and thereby to help improve laying performance in the poultry industry. Results RNA-Seq analysis was carried out on total RNA harvested from the liver of juvenile (n = 3) and laying (n = 3) hens. Compared with juvenile hens, 2567 differentially expressed genes (1082 up-regulated and 1485 down-regulated) with P ≤ 0.05 were obtained in laying hens, and 960 of these genes were significantly differentially expressed (SDE) at a false discovery rate (FDR) of ≤0.05 and fold-change ≥2 or ≤0.5. In addition, most of the 198 SDE novel genes (91 up-regulated and 107 down-regulated) were discovered highly expressed, and 332 SDE isoforms were identified. Gene ontology (GO) enrichment and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis showed that the SDE genes were most enrichment in steroid biosynthesis, PPAR signaling pathway, biosynthesis of unsaturated fatty acids, glycerophospholipid metabolism, three amino acid pathways, and pyruvate metabolism (P ≤ 0.05). The top significantly enriched GO terms among the SDE genes included lipid biosynthesis, cholesterol and sterol metabolic, and oxidation reduction, indicating that principal lipogenesis occurred in the liver of laying hens. Conclusions This study suggests that the majority of changes at the transcriptome level in laying hen liver were closely related to fat metabolism. Some of the SDE uncharacterized novel genes and alternative splicing isoforms that were detected might also take part in lipid metabolism, although this needs further investigation. This study provides valuable information about the expression profiles of mRNAs from chicken liver, and in-depth functional investigations of these mRNAs could provide new insights into the molecular networks of lipid metabolism in chicken liver. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1943-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hong Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Taian Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Chunlin Xu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Dandan Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Junxiao Ren
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Yanmin Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Yadong Tian
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China. .,Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Zhengzhou, 450002, China.
| | - Yanbin Wang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China. .,Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Zhengzhou, 450002, China.
| | - Yuping Jiao
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China. .,Institute of Animal Husbandry and Veterinary Medicine, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China.
| | - Xiangtao Kang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China. .,Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Zhengzhou, 450002, China. .,International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Xiaojun Liu
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450002, China. .,Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Zhengzhou, 450002, China. .,International Joint Research Laboratory for Poultry Breeding of Henan, Henan Agricultural University, Zhengzhou, 450002, China.
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Le Grand A, Bouter A, Couturier A, Mulner-Lorillon O, Le Goff X, Chesnel F, Sire O, Le Tilly V. Investigation of the functional properties and subcellular localization of alpha human and rainbow trout estrogen receptors within a unique yeast cellular context. J Steroid Biochem Mol Biol 2015; 149:17-26. [PMID: 25595040 DOI: 10.1016/j.jsbmb.2015.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/26/2014] [Accepted: 01/11/2015] [Indexed: 12/22/2022]
Abstract
Estrogens are steroid hormones that play a pivotal role in growth, differentiation and function of reproductive and non-reproductive tissues, mediated through estrogen receptors (ERs). Estrogens are involved in different genomic and non-genomic cell signaling pathways which involve well-defined subcellular ER localizations. Thus, ER activity results from complex interplays between intrinsic binding properties and specific subcellular localization. Since these two factors are deeply intricate, we carried out, in a unique yeast cell context, a comparative study to better understand structure/function/subcellular distribution relationships. This was carried out by comparing two ERs: the human ER α subtype (hERα) and the short form of the α isoform of the rainbow trout ER (rtERαS). Their distinct binding properties to agonist and antagonist ligands and subcellular localizations were characterized in Saccharomyces cerevisiae yeast cells. An unexpected partial agonistic effect of ICI 182-780 was observed for rtERαS. Concomitant to distinct binding properties, distinct subcellular localizations were observed before and after ligand stimulation. Due to the unique cell context, the link between ERs intrinsic binding properties and subcellular localizations is partly unveiled and issues are hypothesized based on the role of cytoplasmic transient complexes which play a role in the ER cytoplasmic/nuclear partition, which in turn is critical for the recruitment of co-regulators in the nucleus.
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Affiliation(s)
- Adélaïde Le Grand
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Anthony Bouter
- Molecular Imaging and NanoBioTechnology, UMR 5248 CBMN, CNRS-Université Bordeaux 1-ENITAB, IECB, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Anne Couturier
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Odile Mulner-Lorillon
- CNRS/UPMC Université Paris 06, UMR 8227 LBI2M, Traduction, Cycle Cellulaire et Développement, Station Biologique, CS 90074, 29688 Roscoff Cedex, France
| | - Xavier Le Goff
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Franck Chesnel
- CNRS/Université de Rennes 1, Institut de Génétique & Développement de Rennes, UMR 6290, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes Cedex, France
| | - Olivier Sire
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France
| | - Véronique Le Tilly
- Laboratoire d'Ingénierie des Matériaux de Bretagne, Université de Bretagne-Sud, CER Yves Coppens, BP573, 56017 Vannes Cedex, France.
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9
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Cotter KA, Nacci D, Champlin D, Chuprin J, Callard GV. Cloning of multiple ERα mRNA variants in killifish (Fundulus heteroclitus), and differential expression by tissue type, stage of reproduction, and estrogen exposure in fish from polluted and unpolluted environments. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 159:184-197. [PMID: 25550165 PMCID: PMC4300264 DOI: 10.1016/j.aquatox.2014.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/11/2014] [Accepted: 12/12/2014] [Indexed: 06/04/2023]
Abstract
To test the hypothesis that alternative splicing could be an adaptive mechanism for populations subject to multi-generational estrogenic exposures, we compared estrogen receptor alpha (ERα) splicing variants in two populations of killifish (Fundulus heteroclitus): one resident in an estrogenic polluted environment (New Bedford Harbor, NBH, MA, USA) and one from a relatively uncontaminated reference site (Scorton Creek, SC, MA, USA). In total we identified 19 ERα variants, each with deletions of one or more coding exons. Four of the variants with potential functional relevance were analyzed by qPCR to test for population differences in expression by tissue type, site, sex, seasonal reproductive status and estrogen treatment. Significantly, a 5'-truncated short form variant (ERαS) was highly expressed in liver and ovary, and was associated with seasonal reproductive activity in SC but not NBH fish. Both ERαS and the full-length long variant (ERαL) were estrogen-inducible (ERαS>ERαL) but the induction response was lower in NBH than in SC fish. In contrast, NBH killifish were hyper-responsive to estrogen as measured by expression of two other estrogen responsive genes: vitellogenin (Vtg) and aromatase B (AroB). Most strikingly, two ERα deletion variants (Δ6 and Δ6-8), lacking ligand binding and activation function domains, were identified in a subset of NBH fish, where they were associated with reduced responsiveness to estrogen treatment. Together, these results support the hypothesis that alternative splicing of the esr1 gene of killifish could be an autoregulatory mechanism by which estrogen modulates the differential expression of ERα, and suggests a novel and adaptive mechanistic response to xenoestrogenic exposure.
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Affiliation(s)
- Kellie A Cotter
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
| | - Diane Nacci
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, 27 Tarzwell Drive, Narragansett, RI 02882, USA
| | - Denise Champlin
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, 27 Tarzwell Drive, Narragansett, RI 02882, USA
| | - Jane Chuprin
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
| | - Gloria V Callard
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA.
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10
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Estrogen stimulates expression of chicken hepatic vitellogenin II and very low-density apolipoprotein II through ER-α. Theriogenology 2014; 82:517-24. [DOI: 10.1016/j.theriogenology.2014.05.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 04/29/2014] [Accepted: 05/13/2014] [Indexed: 01/23/2023]
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11
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Aromatase, estrogen receptors and brain development in fish and amphibians. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:152-62. [PMID: 25038582 DOI: 10.1016/j.bbagrm.2014.07.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/19/2014] [Accepted: 07/07/2014] [Indexed: 12/20/2022]
Abstract
Estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. The issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. In this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells in the brain of all vertebrates. Expression of aromatase in the brain of fish is also strongly stimulated by estrogens and some androgens. This creates a very intriguing positive auto-regulatory loop leading to dramatic aromatase expression in sexually mature fish with elevated levels of circulating steroids. Looking at the effects of estrogens or anti-estrogens in the brain of adult zebrafish showed that estrogens inhibit rather than stimulate cell proliferation and newborn cell migration. The functional meaning of these observations is still unclear, but these data suggest that the brain of fish is experiencing constant remodeling under the influence of circulating steroids and brain-derived neurosteroids, possibly permitting a diversification of sexual strategies, notably hermaphroditism. Recent data in frogs indicate that aromatase expression is limited to neurons and do not concern radial glial cells. Thus, until now, there is no other example of vertebrates in which radial progenitors express aromatase. This raises the question of when and why these new features were gained and what are their adaptive benefits. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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12
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Marlatt VL, Sun J, Curran CA, Bailey HC, Kennedy CK, Elphick JR, Martyniuk CJ. Molecular responses to 17β-estradiol in early life stage salmonids. Gen Comp Endocrinol 2014; 203:203-14. [PMID: 24698784 DOI: 10.1016/j.ygcen.2014.03.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 03/11/2014] [Accepted: 03/13/2014] [Indexed: 01/19/2023]
Abstract
Environmental estrogens (EE) are ubiquitous in many aquatic environments and biological responses to EEs in early developmental stages of salmonids are poorly understood compared to juvenile and adult stages. Using 17β-estradiol (E2) as a model estrogen, waterborne exposures were conducted on early life stage rainbow trout (Oncorhynchus mykiss; egg, alevin, swim-up fry) and both molecular and physiological endpoints were measured to quantify the effects of E2. To investigate developmental stage-specific effects, laboratory exposures of 1 μg/L E2 were initiated pre-hatching as eyed embryos or post-hatching upon entering the alevin stage. High mortality (∼90%) was observed when E2 exposures were initiated at the eyed embryo stage compared to the alevin stage (∼35% mortality), demonstrating stage-specific sensitivity. Gene expression analyses revealed that vitellogenin was detectable in the liver of swim-up fry, and was highly inducible by 1 μg/L E2 (>200-fold higher levels compared to control animals). Experiments also confirmed the induction of vitellogenin protein levels in protein extracts isolated from head and tail regions of swim-up fry after E2 exposure. These findings suggest that induction of vitellogenin, a well-characterized biomarker for estrogenic exposure, can be informative measured at this early life stage. Several other genes of the reproductive endocrine axis (e.g. estrogen receptors and androgen receptors) exhibited decreased expression levels compared to control animals. In addition, chronic exposure to E2 during the eyed embryo and alevin stages resulted in suppressive effects on growth related genes (growth hormone receptors, insulin-like growth factor 1) as well as premature hatching, suggesting that the somatotropic axis is a key target for E2-mediated developmental and growth disruptions. Combining molecular biomarkers with morphological and physiological changes in early life stage salmonids holds considerable promise for further defining estrogen action during development, and for assessing the impacts of endocrine disrupting chemicals in vivo in teleosts.
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Affiliation(s)
- Vicki L Marlatt
- Nautilus Environmental, 8664 Commerce Court, Burnaby, British Columbia V5A 4N71, Canada.
| | - Jinying Sun
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada
| | - Cat A Curran
- Nautilus Environmental, 8664 Commerce Court, Burnaby, British Columbia V5A 4N71, Canada
| | - Howard C Bailey
- Nautilus Environmental, 8664 Commerce Court, Burnaby, British Columbia V5A 4N71, Canada
| | - Chris K Kennedy
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada
| | - James R Elphick
- Nautilus Environmental, 8664 Commerce Court, Burnaby, British Columbia V5A 4N71, Canada
| | - Christopher J Martyniuk
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, New Brunswick, Canada
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13
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Cotter KA, Yershov A, Novillo A, Callard GV. Multiple structurally distinct ERα mRNA variants in zebrafish are differentially expressed by tissue type, stage of development and estrogen exposure. Gen Comp Endocrinol 2013; 194:217-29. [PMID: 24090614 PMCID: PMC3862120 DOI: 10.1016/j.ygcen.2013.09.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/04/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
Abstract
It is well established that estrogen-like environmental chemicals interact with the ligand-binding site of estrogen receptors (ERs) to disrupt transcriptional control of estrogen responsive targets. Here we investigate the possibility that estrogens also impact splicing decisions on estrogen responsive genes, such as that encoding ERα itself. Targeted PCR cloning was applied to identify six ERα mRNA variants in zebrafish. Sequencing revealed alternate use of transcription and translation start sites, multiple exon deletions, intron retention and alternate polyadenylation. As determined by quantitative (q)PCR, N-terminal mRNA variants predicting long (ERαA(L)) and short (ERα(S)) isoforms were differentially expressed by tissue-type, sex, stage of development and estrogen exposure. Whereas ERα(L) mRNA was diffusely distributed in liver, brain, heart, eye, and gonads, ERα(S) mRNA was preferentially expressed in liver (female>male) and ovary. Neither ERα(L) nor ERα(S) transcripts varied significantly during development, but 17β-estradiol selectively increased accumulation of ERα(S) mRNA (∼170-fold by 120 hpf), an effect mimicked by bisphenol-A and diethylstilbestrol. Significantly, a C-truncated variant (ERα(S)-Cx) lacking most of the ligand binding and AF-2 domains was transcribed exclusively from the short isoform promoter and was similar to ERα(S) in its tissue-, stage- and estrogen inducible expression. These results support the idea that promoter choice and alternative splicing of the esr1 gene of zebrafish are part of the autoregulatory mechanism by which estrogen modulates subsequent ERα expression, and further suggest that environmental estrogens could exert some of their toxic effects by altering the relative abundance of structurally and functionally distinct ERα isoforms.
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Affiliation(s)
- Kellie A. Cotter
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
| | - Anya Yershov
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
| | - Apolonia Novillo
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
| | - Gloria V. Callard
- Boston University Department of Biology, 5 Cummington Mall, Boston, MA 02215, USA
- Corresponding author: (617-353-8980)
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14
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Raingeard D, Bilbao E, Cancio I, Cajaraville MP. Retinoid X receptor (RXR), estrogen receptor (ER) and other nuclear receptors in tissues of the mussel Mytilus galloprovincialis: Cloning and transcription pattern. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:178-90. [DOI: 10.1016/j.cbpa.2013.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 02/25/2013] [Accepted: 03/02/2013] [Indexed: 01/11/2023]
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15
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Hammouche SB, Remana S, Exbrayat JM. Immunolocalization of hepatic estrogen and progesterone receptors in the female lizard Uromastyx acanthinura. C R Biol 2012; 335:445-53. [PMID: 22847011 DOI: 10.1016/j.crvi.2012.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 05/14/2012] [Accepted: 06/12/2012] [Indexed: 12/06/2022]
Abstract
The hormonal regulation of hepatic synthesis of vitellogenin during the annual reproductive cycle was performed for the first time in the deserticole, oviparous, diurnal and herbivorous Uromastyx acanthinura, a lizard belonging to the Agamidae family. In order to elucidate what kind of estrogen receptor is involved in this process, an immunohistochemical study was performed. Changes were obtained in the labeling and cellular distribution of the estrogen and progesterone receptors according to the period of the reproductive cycle and the experimental administration of 17β-estradiol. Only the ERβ subtype was present; it was found in all phases of the cycle with a variable localization: nuclear and cytosolic during vitellogenesis, mainly cytosolic in the female with egg retention (luteal phase) and strictly cytosolic in females at sexual rest. The progesterone receptors were present only at the luteal phase and during sexual rest and disappeared completely from females after 17β-estradiol treatment in sexual rest. Our data suggested that mediation of action of the 17β-estradiol in the vitellogenin synthesis in the lizard U. acanthinura occured via ERβ. PRA and PRB could both be necessary for the negative effect of progesterone on the hepatic synthesis of vitellogenin.
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Affiliation(s)
- Sadjia Benmansour Hammouche
- Aride Area Research Laboratory, Biological Sciences Faculty, University of Sciences and Technology of Houari Boumediene, USTHB, Algiers, Algeria.
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16
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Nicol-Benoit F, Amon A, Vaillant C, le Goff P, le Dréan Y, Pakdel F, Flouriot G, Valotaire Y, Michel D. A dynamic model of transcriptional imprinting derived from the vitellogenesis memory effect. Biophys J 2012; 101:1557-68. [PMID: 21961581 DOI: 10.1016/j.bpj.2011.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/23/2011] [Accepted: 07/05/2011] [Indexed: 01/27/2023] Open
Abstract
Transcriptional memory of transient signals can be imprinted on living systems and influence their reactivity to repeated stimulations. Although they are classically ascribed to structural chromatin rearrangements in eukaryotes, such behaviors can also rely on dynamic memory circuits with sustained self-amplification loops. However, these phenomena are either of finite duration, or conversely associated to sustained phenotypic changes. A mechanism is proposed, in which only the responsiveness of the target gene is durably reset at a higher level after primary stimulation, using the celebrated but still puzzling vitellogenesis memory effect. The basic ingredients of this system are: 1), a positive autoregulation of the estrogen receptor α gene; 2), a strongly cooperative action of the estradiol receptor on vitellogenin expression; and 3), a variant isoform of the estradiol receptor with two autonomous transcription-activating modules, one of which is signal-independent and the other, signal-dependent. Realistic quantification supports the possibility of a multistationary situation in which ligand-independent activity is unable by itself to prime the amplification loop, but can click the system over a memory threshold after a primary stimulation. This ratchet transcriptional mechanism can have developmental and ecotoxicological importance and explain lifelong imprinting of past exposures without apparent phenotypic changes before restimulation and without need for persistent chromatin modifications.
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Affiliation(s)
- Floriane Nicol-Benoit
- UMR6026 Interactions Cellulaires et Moléculaires IFR140 GFAS Irset, Université de Rennes1, Rennes, France
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17
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Pri-Tal BM, Blue S, Pau FKY, Podrabsky JE. Hormonal components of altered developmental pathways in the annual killifish, Austrofundulus limnaeus. Gen Comp Endocrinol 2011; 174:166-74. [PMID: 21906598 DOI: 10.1016/j.ygcen.2011.08.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 08/18/2011] [Accepted: 08/21/2011] [Indexed: 10/17/2022]
Abstract
The annual killifish, Austrofundulus limnaeus, typically enters embryonic diapause at two distinct points of development, termed diapause II and III. This study explores the role of maternal and embryonic steroid hormones, including 17-β-estradiol (E2), androstenedione (A4) and testosterone (T), in regulating the developmental decision to enter or escape diapause II. Steroid hormone levels were measured in tissues isolated from adult female killifish during the normal lifespan of this species and in individuals of the same age that were producing either high or low proportions of escape embryos. Levels of steroid hormones were also measured during early development and in fertilized eggs that were predicted to be on either an escape or diapausing developmental trajectory. Decreases in maternal E2 levels associated with age are correlated with decreasing escape embryo production. Maternal production of escape embryos is correlated with increased ratios of E2 to T in adult ovary tissue. Interestingly, neither hormone is significantly different in fish producing embryos on different developmental pathways when examined independently. Levels of steroid hormones in fertilized eggs are not correlated with entry or escape from diapause II, though levels of A4 tend to be higher in escape embryos. Escape embryos exhibit faster hormone metabolism and earlier hormone synthesis than embryos that will enter diapause II. Incubation of embryos in exogenous E2 is associated with a 7-fold increase in escape embryo production, and significantly elevated A4 levels. These data suggest that steroid hormones may be critical factors involved in determining developmental pathways in embryos of A. limnaeus.
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Affiliation(s)
- Benjamin M Pri-Tal
- Department of Biology, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA
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18
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Forlano PM, Bass AH. Neural and hormonal mechanisms of reproductive-related arousal in fishes. Horm Behav 2011; 59:616-29. [PMID: 20950618 PMCID: PMC3033489 DOI: 10.1016/j.yhbeh.2010.10.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 10/02/2010] [Indexed: 01/05/2023]
Abstract
The major classes of chemicals and brain pathways involved in sexual arousal in mammals are well studied and are thought to be of an ancient, evolutionarily conserved origin. Here we discuss what is known of these neurochemicals and brain circuits in fishes, the oldest and most species-rich group of vertebrates from which tetrapods arose over 350 million years ago. Highlighted are case studies in vocal species where well-delineated sensory and motor pathways underlying reproductive-related behaviors illustrate the diversity and evolution of brain mechanisms driving sexual motivation between (and within) sexes. Also discussed are evolutionary insights from the neurobiology and reproductive behavior of elasmobranch fishes, the most ancient lineage of jawed vertebrates, which are remarkably similar in their reproductive biology to terrestrial mammals.
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Affiliation(s)
- Paul M. Forlano
- Department of Biology and Aquatic Research and Environmental Assessment Center, Brooklyn College of The City University of New York, 2900 Bedford Ave, Brooklyn, NY 11210, USA;
| | - Andrew H. Bass
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA;
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19
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Munchrath LA, Hofmann HA. Distribution of sex steroid hormone receptors in the brain of an African cichlid fish, Astatotilapia burtoni. J Comp Neurol 2010; 518:3302-26. [PMID: 20575061 DOI: 10.1002/cne.22401] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Sex steroid hormones released from the gonads play an important role in mediating social behavior across all vertebrates. Many effects of these gonadal hormones are mediated by nuclear steroid hormone receptors, which are crucial for integration in the brain of external (e.g., social) signals with internal physiological cues to produce an appropriate behavioral output. The African cichlid fish Astatotilapia burtoni presents an attractive model system for the study of how internal cues and external social signals are integrated in the brain as males display robust plasticity in the form of two distinct, yet reversible, behavioral and physiological phenotypes depending on the social environment. In order to better understand where sex steroid hormones act to regulate social behavior in this species, we have determined the distribution of the androgen receptor, estrogen receptor alpha, estrogen receptor beta, and progesterone receptor mRNA and protein throughout the telencephalon and diencephalon and some mesencephalic structures of A. burtoni. All steroid hormone receptors were found in key brain regions known to modulate social behavior in other vertebrates including the proposed teleost homologs of the mammalian amygdalar complex, hippocampus, striatum, preoptic area, anterior hypothalamus, ventromedial hypothalamus, and ventral tegmental area. Overall, there is high concordance of mRNA and protein labeling. Our results significantly extend our understanding of sex steroid pathways in the cichlid brain and support the important role of nuclear sex steroid hormone receptors in modulating social behaviors in teleosts and across vertebrates.
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Affiliation(s)
- Lauren A Munchrath
- Section of Integrative Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78705, USA
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20
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Verderame M, Limatola E. Molecular identification of estrogen receptors (ERalpha and ERbeta) and their differential expression during VTG synthesis in the liver of lizard Podarcis sicula. Gen Comp Endocrinol 2010; 168:231-8. [PMID: 20417209 DOI: 10.1016/j.ygcen.2010.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 03/22/2010] [Accepted: 04/20/2010] [Indexed: 01/29/2023]
Abstract
In non-mammalian vertebrates yolk deposition in the oocytes is a hormone-dependent, gender-specific process. Produced by the ovary under gonadotropin stimulation, Estradiol 17-beta (E(2)) plays a key role in the liver synthesis of vitellogenin (VTG) which in turn is taken up by vitellogenic oocytes in the ovary. In many species a negative role in liver synthesis of VTG in females is also played by progesterone. Experimental administration of E(2) induces the expression of the VTG silent gene also in the liver of males of all the species studied. However, the role of the two isoforms of estrogen receptors, ERalpha and beta, in this process is still unclear. In order to elucidate what kind of ER is involved in the liver synthesis of VTG in the lizard Podarcis sicula, we obtained by means of RT-PCR two fragments of 430bp and 130bp from total ovarian mRNA, encoding respectively for ERalpha and ERbeta. Expression analysis of these two specific isoforms of ERs in the liver showed that in non-breeding females, and in wildlife untreated males only ERbeta is expressed. In breeding vitellogenic females and in E(2)-treated males both alpha and beta receptors are expressed. Furthermore, in females experimentally treated with progesterone during the breeding period, expression of ERalpha disappears. Conversely, treatment of females with E(2) in the non-breeding period induces expression of ERalpha. Immunohistochemical analysis and Western blotting showed that the presence of irVTG in liver and plasma is always parallel to hepatic expression of ERalpha in all the different experimental conditions. Our data strongly suggest that expression of ERalpha may be necessary for VTG synthesis in Podarcis. The possible modulatory role of ERbeta is also discussed.
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Affiliation(s)
- Mariailaria Verderame
- Department of Biological Sciences, Evolutionary and Comparative Biology Division, University of Naples Federico II, Via Mezzocannone 8, 80134 Naples, Italy.
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21
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Muncaster S, Andersson E, Kjesbu OS, Taranger GL, Skiftesvik AB, Norberg B. The reproductive cycle of female Ballan wrasse Labrus bergylta in high latitude, temperate waters. JOURNAL OF FISH BIOLOGY 2010; 77:494-511. [PMID: 20701636 DOI: 10.1111/j.1095-8649.2010.02691.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This 2 year study examined the reproductive cycle of wild female Ballan wrasse Labrus bergylta in western Norway as a precursor to captive breeding trials. Light microscopy of ovarian histology was used to stage gonad maturity and enzyme-linked immuno-absorbent assay (ELISA) to measure plasma concentrations of the sex steroids testosterone (T) and 17beta-oestradiol (E(2)). Ovarian recrudescence began in late autumn to early winter with the growth of previtellogenic oocytes and the formation of cortical alveoli. Vitellogenic oocytes developed from January to June and ovaries containing postovulatory follicles (POF) were present between May and June. These POF occurred simultaneously among other late maturity stage oocytes. Plasma steroid concentration and organo-somatic indices increased over winter and spring. Maximal (mean +/-s.e.) values of plasma T (0.95 +/- 0.26 ng ml(-1)), E(2) (1.75 +/- 0.43 ng ml(-1)) and gonado-somatic index (I(G); 10.71 +/- 0.81) occurred in April and May and decreased greatly in July when only postspawned fish with atretic ovaries occurred. Evidence indicates that L. bergylta are group-synchronous multiple spawners with spawning occurring in spring and peaking in May. A short resting period may occur between late summer and autumn when previtellogenic oocytes predominate and steroid levels are minimal.
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Affiliation(s)
- S Muncaster
- Institute of Marine Research, P.O. Box 187, Nordnes, N-5817 Bergen, Norway.
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22
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Control of vitellogenin genes expression by sequences derived from transposable elements in rainbow trout. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:546-54. [DOI: 10.1016/j.bbagrm.2010.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 07/05/2010] [Accepted: 07/09/2010] [Indexed: 01/24/2023]
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23
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Woods M, Kumar A, Barton M. Nucleotide sequence, tissue expression patterns and phylogenetic analysis of estrogen receptor one mRNA in the Murray rainbowfish (Melanotaenia fluviatilis) (Atheriniformes, Actinopterygii). Gen Comp Endocrinol 2010; 166:529-36. [PMID: 20171224 DOI: 10.1016/j.ygcen.2010.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 02/12/2010] [Accepted: 02/15/2010] [Indexed: 11/15/2022]
Abstract
Estrogens are steroidal hormones that control many physiological processes in both female and male vertebrates. Like other vertebrates, fish have two distinct estrogen receptors (Esr) subtypes, Esr1 and Esr2a that have been isolated in a number of species, as well as a third subtype, Esr2b. The mRNA encoding the Esr1 was isolated from the female liver of an Australian freshwater fish, the Murray rainbowfish, Melanotaenia fluviatilis. The rainbowfish esr1 cDNA was 2569 bp in length and with an open reading frame to encode a protein of 611 amino acids. Phylogenetic analysis and multiple amino acid sequence alignment indicated close relationship and high similarity with killifish (Fundulus heteroclitus) and gilthead sea bream (Sparus aurata). Expression of rainbowfish esr1 mRNA was abundant in the liver, gonads and intestine of adult female and male rainbowfish. This is the first isolation of the full-length nucleotide sequence of an estrogen receptor from rainbowfish. This sequence provides a valuable molecular tool that can be used in future studies investigating estrogen mechanisms, actions and tissue-specific expression in juvenile and adult rainbowfish.
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Affiliation(s)
- Marianne Woods
- Centre for Environmental Contaminants Research, CSIRO Land and Water, PMB 2, Glen Osmond 5064, Australia.
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24
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Palstra AP, Schnabel D, Nieveen MC, Spaink HP, van den Thillart GEEJM. Temporal expression of hepatic estrogen receptor 1, vitellogenin1 and vitellogenin2 in European silver eels. Gen Comp Endocrinol 2010; 166:1-11. [PMID: 19766647 DOI: 10.1016/j.ygcen.2009.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 07/17/2009] [Accepted: 09/09/2009] [Indexed: 10/20/2022]
Abstract
Because European silver eels have never been caught during or after their 6000-km reproductive migration to the Sargasso Sea, all existing knowledge on their sexual maturation comes from hormonal stimulation. Silver eels that start their oceanic migration are still immature with pre-vitellogenic oocytes. Hence we assumed that vitellogenesis should start with the expression of the estrogen receptor in the liver before the circulating 17beta-estradiol (E2) can have any effect. In this study we followed the hepatic vitellogenesis upon 4 weekly injections with carp pituitary extracts (CPE). New molecular primers for the expression of the estrogen receptor 1 (esr1), vitellogenin1 (vtg1) and vitellogenin2 (vtg2) in the liver were developed. Sequences of vtg2 and esr1 were not previously described in Anguilla anguilla. All eels showed weekly increase of the eye size and pectoral fin length, which are signs of early maturation. The same occurred with the gonadosomatic index, the oocyte stage and diameter, and number of deposited fat droplets. Early vitellogenesis appeared as a 3-step process (1) E2-levels and esr1 expression were significantly increased already after one injection, (2) vtg1 and vtg2 expression were significantly increased after one and two injections, respectively, and (3) vtg1 and vtg2 expression increased further after three and four injections. Then also plasma calcium (corresponds with plasma vitellogenin) increased and yolk globuli appeared in the oocytes. These results show that esr1 is the first of the three genes examined that is expressed during the onset of hepatic vitellogenesis. Furthermore, ovarian vitellogenesis (appearance of yolk globuli in oocytes) occurs 1-2 weeks later than the onset of hepatic vitellogenesis.
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Affiliation(s)
- Arjan P Palstra
- Molecular Cell Biology, Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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25
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Calvel P, Kervarrec C, Lavigne R, Vallet-Erdtmann V, Guerrois M, Rolland AD, Chalmel F, Jégou B, Pineau C. CLPH, a novel casein kinase 2-phosphorylated disordered protein, is specifically associated with postmeiotic germ cells in rat spermatogenesis. J Proteome Res 2009; 8:2953-65. [PMID: 19271754 DOI: 10.1021/pr900082m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a recent proteomic study of rat spermatogenesis, we identified CLPH (for Casein-Like PHosphoprotein), a new testis-specific protein expressed exclusively in postmeiotic germ cells. In situ hybridization showed that the CLPH transcript was mainly present in round spermatids, whereas the protein was specifically detected by immunohistochemistry in elongated spermatids and in residual bodies. Electron microscopy showed the protein to be mostly cytoplasmic, but also frequently associated with the mitochondrial inner membrane during the last steps of spermatid differentiation. The Clph gene was found to be present solely in mammalian genomes, in a chromosomal region syntenic to the mammalian cluster of secretory calcium-binding phosphoprotein (SCPP) genes. CLPH has several distinctive properties in common with SCPPs: calcium overlay experiments showed that CLPH was a calcium-binding protein, whereas trypsin digestion assay, circular dichroism and fluorescence experiments demonstrated its intrinsically disordered structure. We also showed that CLPH was phosphorylated in vitro and in vivo by casein kinase 2, an enzyme critical for spermatid elongation. Given the specific and strong production of CLPH during rat spermiogenesis, together with the particular biochemical properties of this protein, we suggest that CLPH is involved in the extremely complex structural rearrangements occurring in haploid germ cells during spermiogenesis.
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Affiliation(s)
- Pierre Calvel
- Inserm, U625, Rennes, Universite Rennes I, Campus de Beaulieu, IFR-140, GERHM, Rennes, F-35042, France
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26
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Woods M, Kumar A, Barton M, Woods A, Kookana R. Localisation of estrogen responsive genes in the liver and testis of Murray rainbowfish Melanotaenia fluviatilis exposed to 17beta-estradiol. Mol Cell Endocrinol 2009; 303:57-66. [PMID: 19428992 DOI: 10.1016/j.mce.2008.12.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 11/19/2008] [Accepted: 12/31/2008] [Indexed: 10/21/2022]
Abstract
The localisation of estrogen receptors (ERalpha and ERbeta) and vitellogenin (VTG) transcripts were examined in the liver and testis in male rainbowfish exposed to 17beta-estradiol (E2; 0, 50 and 500 ng/L) via the water for up to 7 days. The ER transcripts were localised within the perinuclear region of the hepatocytes and were up-regulated with E2 exposure. A parallel induction of liver VTG transcripts and protein was observed within 24h, followed by a time-dependent increase in VTG protein. In the testis, both ERs were up-regulated in the germ and epithelial cells, while VTG protein was detected in the cellular space surrounding the spermatids and in association with the connective tissue of the sperm tubules. These results indicate that the ERs are positively auto-regulated in the liver and testis of male rainbowfish. The cellular localisation of VTG within the testis may suggest implication in the mediation of adverse effects of endocrine disrupting chemicals such as testicular growth inhibition, testis-ova and sex reversal.
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Affiliation(s)
- Marianne Woods
- Centre for Environmental Contaminants Research, CSIRO Land and Water, Glen Osmond, Australia.
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27
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Pinto PIS, Estêvão MD, Redruello B, Socorro SM, Canário AVM, Power DM. Immunohistochemical detection of estrogen receptors in fish scales. Gen Comp Endocrinol 2009; 160:19-29. [PMID: 18977356 DOI: 10.1016/j.ygcen.2008.10.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2008] [Revised: 09/30/2008] [Accepted: 10/01/2008] [Indexed: 01/11/2023]
Abstract
Calcium mobilization from internal stores, such as scales, induced by 17beta-estradiol during sexual maturation in salmonids is well documented. This calcium mobilization from scales is proposed to be mediated by the estrogen receptor (ER). However, the ER subtypes involved and signaling mechanisms responsible for this effect remain to be fully characterized. In the present study, we have localized ERalpha, ERbetaa and ERbetab proteins in juvenile and adult sea bream (Sparus auratus) and Mozambique tilapia (Oreochromis mossambicus) scales by immunohistochemistry with sea bream ER subtype specific antibodies. The three ERs were detected in isolated or small groups of round cells, in the basal layer of the scales of both juvenile and adult fish and the localization and signal intensity varied with the species and age of the animals. The ERs may be co-localized in cells of the scale posterior region that expressed tartrate-resistant acid phosphatase (TRAP), a marker for osteoclasts. These results suggest that the calcium mobilizing action of 17beta-estradiol on fish scales is via its direct action on ERs localized in osteoclasts.
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Affiliation(s)
- P I S Pinto
- Centro de Ciências do Mar, CIMAR-Laboratório Associado, University of Algarve, Campus de Gambelas, Faro, Portugal.
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28
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Raingeard D, Cancio I, Cajaraville MP. Cloning and expression pattern of peroxisome proliferator-activated receptors, estrogen receptor alpha and retinoid X receptor alpha in the thicklip grey mullet Chelon labrosus. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:26-35. [PMID: 18619562 DOI: 10.1016/j.cbpc.2008.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 06/17/2008] [Accepted: 06/17/2008] [Indexed: 02/07/2023]
Abstract
Aquatic organisms are exposed to diverse xenobiotics that cause peroxisome proliferation and/or endocrine disruption, both modulated in vertebrates by transcription factors of the nuclear receptor (NR) superfamily. Peroxisome proliferators are agonists of peroxisome proliferator-activated receptors (PPARs) that heterodimerize with the retinoid X receptor (RXR). Many xenoestrogens activate the estrogen receptor (ER). Here, 1090 bp of PPARalpha, 1255 bp of PPARgamma, 278 bp of RXRalpha, and 578 bp of ERalpha of thicklip grey mullet Chelon labrosus were cloned. Sequences were highly conserved, although relevant changes with respect to mammalian homologs were identified in PPARgamma and ERalpha. Semi-quantitative RT-PCR was used to determine if these NRs were expressed in different tissues of male, female and undifferentiated mullets captured in January and June. Expression of PPARs was highest in liver and lowest in muscle. RXRalpha expression was homogeneous excepting a low expression in male and female gill in January and brain and heart of undifferentiated fish in January and June. ERalpha expression predominated in liver and female gonad in June. The expression level of PPARs and ERalpha was significantly higher in liver in January than in gills in January or June. The present results show tissue-dependent modulation of expression of NRs in mullets.
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Affiliation(s)
- Damien Raingeard
- Laboratory of Cell Biology and Histology, Department of Zoology and Animal Cell Biology, University of the Basque Country, Bilbao, Basque Country, Spain
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29
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Ko CI, Chesnel A, Mazerbourg S, Kuntz S, Flament S, Chardard D. Female-enriched expression of ERalpha during gonad differentiation of the urodele amphibian Pleurodeles waltl. Gen Comp Endocrinol 2008; 156:234-45. [PMID: 18321504 DOI: 10.1016/j.ygcen.2008.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/09/2008] [Accepted: 01/16/2008] [Indexed: 11/20/2022]
Abstract
In the amphibian Pleurodeles waltl, estradiol treatment of genetically male larvae (ZZ) induces male-to-female sex reversal whereas heat treatment of genetically female larvae (ZW) inhibits estradiol synthesis and leads to female-to-male sex reversal. No data are available on estrogen receptors in this species. In the present study, we have isolated a unique full-length pwERalpha cDNA and its 5'-flanking region whose promoter activity was confirmed by transfection assays. RT-PCR studies performed in adult animals using ERalpha-specific primers, revealed that pwERalpha mRNA was present mainly in reproductive tissues: gonads, fat body and oviduct. PwERalpha transcript was also detected in liver, suggesting its implication in vitellogenesis control as in numerous oviparous species. The level of pwERalpha transcripts was also studied during gonad differentiation by quantitative real-time PCR. At stage 54(30d) pwERalpha expression in gonads of ZW larvae was significantly higher than in ZZ ones. This sex-specific discrimination was confirmed when gonad-mesonephros-interrenal complexes (GMI), taken at the same stage, were subjected to whole mount in situ hybridization. In comparison, the female-enriched expression of P450 aromatase, which was studied as a control of ovary differentiation, was observed earlier (stage 54). In ZW larvae reared at 32 degrees C, a condition leading to sex reversal, pwERalpha mRNA level at stage 54(30d) was lower than in control females. Taken together, these results showing a female-enriched and thermosensitive expression of pwERalpha suggest an important role for this receptor in gonad differentiation of the urodele amphibian Pleurodeles waltl.
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Affiliation(s)
- Chia-I Ko
- Nancy-Université, Faculté des Sciences, EA3442 Aspects Cellulaires et Moléculaires de la Reproduction et du Développement, Vandoeuvre-lès-Nancy Cedex, France
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30
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Tollefsen KE, Julie Nilsen A. Binding of alkylphenols and alkylated non-phenolics to rainbow trout (Oncorhynchus mykiss) hepatic estrogen receptors. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 69:163-72. [PMID: 17512592 DOI: 10.1016/j.ecoenv.2007.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/09/2007] [Accepted: 04/08/2007] [Indexed: 05/15/2023]
Abstract
Alkylphenols are well-known endocrine disrupters, mediating effects through the estrogen receptor (ER). In the present work, the interaction of alkylphenols and alkylated non-phenolics with hepatic rainbow trout (Oncorhynchus mykiss) estrogen receptors (rtERs) was determined. The role of alkyl chain length and branching, substituent position, number of alkylated groups, and the requirement of a phenolic ring structure was assessed. The results showed that the rtERs bound most alkylphenols, although with 20,000 to 2 million times lower affinity than the endogenous estrogen 17beta-estradiol. Mono-substituted alkylphenols with moderate (C4-C6) and long (C8 and C12) alkyl chain length in the para position exhibited the highest affinity for the rtERs. Substitution with multiple alkyl groups, presence of substituents in the ortho- and meta-position, and lack of a hydroxyl group on the benzene ring reduced the binding affinity. The rtERs resembled the reported binding specificity of the human ER for alkylphenols, although some exceptions were identified.
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Affiliation(s)
- Knut-Erik Tollefsen
- Norwegian Institute for Water Research, Gaustadallèen 21, N-0349 Oslo, Norway.
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31
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Rempel MA, Schlenk D. Effects of Environmental Estrogens and Antiandrogens on Endocrine Function, Gene Regulation, and Health in Fish. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 267:207-52. [DOI: 10.1016/s1937-6448(08)00605-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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32
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Molecular characterization and sex-specific tissue expression of estrogen receptor α (esr1), estrogen receptor βa (esr2a) and ovarian aromatase (cyp19a1a) in yellow perch (Perca flavescens). Comp Biochem Physiol B Biochem Mol Biol 2008; 149:126-47. [DOI: 10.1016/j.cbpb.2007.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 08/31/2007] [Accepted: 09/01/2007] [Indexed: 11/22/2022]
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33
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Muriach B, Cerdá-Reverter JM, Gómez A, Zanuy S, Carrillo M. Molecular characterization and central distribution of the estradiol receptor alpha (ERalpha) in the sea bass (Dicentrarchus labrax). J Chem Neuroanat 2007; 35:33-48. [PMID: 17629451 DOI: 10.1016/j.jchemneu.2007.05.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 05/29/2007] [Accepted: 05/29/2007] [Indexed: 11/23/2022]
Abstract
Three different estrogen receptors (ERs) have been cloned and characterized in teleosts fish, i.e. ERalpha, ERbeta or ERbeta1 and ERgamma or ERbeta2. In order to study the sea bass ER subtype involved in the regulation of gonadotropin production, as well as to elucidate the possible involved neuronal pathways, we characterized the transactivation properties of the cloned sea bass ERalpha (sbERalpha) and studied its distribution in the brain and gonadotropic cells of the sea bass by in situ hybridization. The results revealed that sbERalpha transactivates promoters containing estradiol responsive elements (ERE) in a dose-response manner. The sbERalpha showed the highest affinity for 17-beta-estradiol. In situ hybridization studies demonstrated that ERalpha mRNA positive neurons are widely distributed within the sea bass brain, including the telencephalon, preoptic area, thalamus, hypothalamus, mesencephalic tectum and tegmentum and rhombencephalon. New estrogen dependent nuclei were described in all above areas. The sbERalpha was profusely expressed in the main neuroendocrine areas such as the preoptic area and hypothalamus, thus suggesting the steroidal modulation of the hypophysiotropic neurons. The presence of sbERalpha expression in the FSHbeta and LHbeta cells suggests a direct effect of estrogens in the control of gonadotropin hormone synthesis.
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Affiliation(s)
- Borja Muriach
- Department of Fish Physiology and Biotechnology, Instituto de Acuicultura de Torre de la Sal, CSIC, Torre de la Sal, 12595 Ribera de Cabanes, Castellón, Spain
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34
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Roulet V, Satie AP, Ruffault A, Le Tortorec A, Denis H, Guist'hau O, Patard JJ, Rioux-Leclerq N, Gicquel J, Jégou B, Dejucq-Rainsford N. Susceptibility of human testis to human immunodeficiency virus-1 infection in situ and in vitro. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 169:2094-103. [PMID: 17148672 PMCID: PMC1762481 DOI: 10.2353/ajpath.2006.060191] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Semen represents the main vector for human immunodeficiency virus (HIV) dissemination worldwide and has been shown to harbor replication-competent virus despite otherwise effective highly active anti-retroviral therapy, which achieves undetectable viral load in plasma. Despite this, the origin of seminal HIV particles remains unclear, as does the question of whether the male genital tract organs contribute virus to semen. Here we investigated the presence of HIV receptors within the human testis using immunohistochemistry and quantitative real-time polymerase chain reaction. We also analyzed the infectivity of a dual tropic HIV-1 strain in an organotypic culture, as well as the impact of viral exposure on testosterone production. Our study establishes that CXCR4+, CCR5+, CD4+, and DC-SIGN+ cells are present within the interstitial tissue of human testis and that these molecules persist throughout our organotypic culture. Our data also reveal that the human testis is permissive to HIV-1 and supports productive infection, leaving testosterone production apparently unaffected. Infected cells appeared to be testicular macrophages located within the interstitial tissue. That the testis itself represents a potential source of virus in semen could play a role in preventing viral eradication from semen because this organ constitutes a pharmacological sanctuary for many current antiretrovirals.
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Affiliation(s)
- Vanessa Roulet
- INSERM U625-GERHM, Campus Scientifique de Beaulieu, Avenue du Général Leclerc, 35 042 Rennes Cedex, France
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35
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Greytak SR, Callard GV. Cloning of three estrogen receptors (ER) from killifish (Fundulus heteroclitus): differences in populations from polluted and reference environments. Gen Comp Endocrinol 2007; 150:174-88. [PMID: 16962596 DOI: 10.1016/j.ygcen.2006.07.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 06/10/2006] [Accepted: 07/26/2006] [Indexed: 11/18/2022]
Abstract
Epidemiological, wildlife, and laboratory studies support the hypothesis that chemicals released into the environment through anthropogenic activities are responsible for abnormalities of reproduction and development. Although the New Bedford Harbor (NBH) killifish population has survived and reproduced successfully for >50 yr ( approximately 20 generations), fish have high body burdens of the major NBH contaminants (polychlorinated biphenyls); elevated levels of P450 aromatase B and vitellogenin mRNA (markers of estrogen effect); and evidence of endocrine disruption. To investigate possible adaptive changes in the estrogen response system of NBH killifish, we cloned the estrogen receptors (ER) from killifish populations resident in NBH and a relatively unpolluted reference site (Scorton Creek MA, SC). ERalpha, -betaa, and -betab cDNAs encoding full-length polypeptides of 620, 543, and 672 amino acids, respectively, were identified. Each ER subtype had multiple splice variants, single nucleotide polymorphisms (SNPs), and a characteristic tissue distribution and developmental profile. As measured by real-time quantitative RT-PCR analysis, the overall tissue distribution of each ER was similar in NBH and SC fish, implying that the regulatory pathways which maintain tissue-specific expression are largely unchanged by long term pollutant exposure. Nonetheless, a striking difference was seen in the quantity of mRNA of the estrogen-inducible gene ERalpha, which was significantly lower in brain, liver and ovaries of reproductively active NBH as compared to SC females. Paradoxically, despite the "estrogenic" NBH environment, ERalpha mRNA levels did not differ in reproductively inactive NBH and SC females, or in males at the two sites at any time of year. We interpret results in NBH fish as due in part to a deficit of circulating estrogen, and in part to pollutant-mediated hyporesponsiveness of the ERalpha gene. In marked contrast to adult fish, ERalpha was elevated approximately 5-fold in NBH as compared to SC embryos/larvae, perhaps indicative of estrogenic chemicals in yolk. We conclude that contaminants in the NBH environment impact molecular components of the estrogen signaling pathways in resident killifish populations. Whether these changes are transient or heritable requires further study.
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Affiliation(s)
- Sarah R Greytak
- Department of Biology, Boston University, Boston, MA 02215, USA
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36
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Andersson ML, Eggen RI. Transcription of the fish Latent TGFβ-binding protein gene is controlled by estrogen receptor α. Toxicol In Vitro 2006; 20:417-25. [PMID: 16171970 DOI: 10.1016/j.tiv.2005.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 08/08/2005] [Indexed: 10/25/2022]
Abstract
In endocrine disruption a key role has been suggested for endocrine receptors, in particular the estrogen receptors (ERs), in the regulation by compounds mimicking natural hormones. The two ERs, ERalpha and ERbeta are transcription factors involved in the regulated expression of estrogen target genes and have been shown to play an essential role in mammalian ovary development. A similar role is to be expected for ERs in fish; little is, however, known in fish about genes regulated by ERs. To begin to address this, we here report the identification and characterization of a novel gene regulated by the fish ERalpha in response to 17beta-estradiol. This gene encodes a fish orthologue of the latent transforming growth factor beta binding protein 3 (LTBP-3) and was identified through a differential display approach from a rainbow trout gonad cell line (RTG-2-ERalpha). We show that the rainbow trout LTBP (rtLTBP-3) is ERalpha dependent and is upregulated 5-fold in response to 17beta-estradiol addition. The rtLTBP shows 61% amino acid similarity to human LTBP-3 and 48%, 44% and 41% to LTBP-1, LTBP-2 and LTBP-4, respectively. The highly conserved TB2 domain of rtLTBP shows 87% and 66% identity to the TB domains of human LTBP-3 and LTBP-1, respectively. LTBP plays a pivotal role in TGFbeta activation in mammals and the high degree of sequence similarity suggests a similar role in fish. This would represent a novel link between nuclear hormone receptors and growth factor (TGFbeta) mediated developmental processes, and show new aspects of the role of hormones in developmental biology and endocrine disruption.
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Affiliation(s)
- Monika L Andersson
- Department of Biosciences, Karolinska Institute, Novum, SE 14157, Huddinge, Sweden.
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Vetillard A, Bailhache T. Effects of 4-n-Nonylphenol and Tamoxifen on Salmon Gonadotropin-Releasing Hormone, Estrogen Receptor, and Vitellogenin Gene Expression in Juvenile Rainbow Trout. Toxicol Sci 2006; 92:537-44. [PMID: 16705041 DOI: 10.1093/toxsci/kfl015] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Alkylphenols such as nonylphenol (NP) are one of a wide variety of environmental chemicals reported to have estrogenic effects in both in vitro and in vivo studies. Induction of hepatic vitellogenin (Vg) gene expression is widely used as a biomarker for xenoestrogen exposure in fish. However, little work has been done to characterize the molecular effects of xenoestrogens on other potential target organs such as the brain. To evaluate brain and liver effects of 4-n-nonylphenol (4-NP), juvenile rainbow trout (Oncorhynchus mykiss) were exposed to waterborne 4-NP or 17beta-estradiol (E(2)). Changes in mRNA levels of salmon gonadotropin-releasing hormone (sGnRH) and estrogen receptor alpha (ERalpha) isoforms in the brain and ERalpha isoforms and Vg in the liver were measured after 3 and 6 days of exposure, with the help of a relative RT-PCR-based quantification method. Fish were treated with increasing doses of 4-NP ranging from 0.01 to 10 microM (2.2 microg/l to 2.2 mg/l), and results were compared to the effect of E(2) or tamoxifen, a specific ER modulator. In liver, E(2) and the highest doses of 4-NP increased Vg and ERalpha long-isoform mRNA levels within 3 or 6 days of exposure, but 4-NP did not have any effect on ERalpha short-isoform transcription level. In the brain, 4-NP reduced sGnRH2 gene expression in a dose-dependent manner, but did not modify sGnRH1 or ERalpha mRNA levels.
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Affiliation(s)
- Angelique Vetillard
- MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom.
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38
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Chen M, Beaven S, Tontonoz P. Identification and characterization of two alternatively spliced transcript variants of human liver X receptor alpha. J Lipid Res 2005; 46:2570-9. [PMID: 16170053 DOI: 10.1194/jlr.m500157-jlr200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The liver X receptor alpha (LXRalpha) is a member of the nuclear hormone receptor superfamily that plays an important role in lipid homeostasis. Here we characterize two alternative human LXRalpha transcripts, designated LXRalpha2 and LXRalpha3. All three LXRalpha isoforms are derived from the same gene via alternative splicing and differential promoter usage. The LXRalpha2 isoform lacks the first 45 amino acids of LXRalpha1, and is generated through the use of a novel promoter and first exon. LXRalpha3 lacks 50 amino acids within the ligand binding domain and is generated through alternative recognition of the 3'-splice site in exon 6. LXRalpha2 and LXRalpha3 are expressed at lower levels compared with LXRalpha1 in most tissues, except that LXRalpha2 expression is dominant in testis. Both LXRalpha2 and LXRalpha3 heterodimerize with the retinoid X receptor and bind to LXR response elements. LXRalpha2 shows reduced transcriptional activity relative to LXRalpha1, indicating that the N-terminal domain of LXRalpha is essential for its full transcriptional activity. LXRalpha3 is unable to bind ligand and is transcriptionally inactive. These observations outline a previously unrecognized role for the N terminus in LXR function and suggest that the expression of alternative LXRalpha transcripts in certain biological contexts may impact LXR signaling and lipid metabolism.
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Affiliation(s)
- Mingyi Chen
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095, USA
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Larivière K, Samia M, Lister A, Van Der Kraak G, Trudeau VL. Sex steroid regulation of brain glutamic acid decarboxylase (GAD) mRNA is season-dependent and sexually dimorphic in the goldfish Carassius auratus. ACTA ACUST UNITED AC 2005; 141:1-9. [PMID: 16226340 DOI: 10.1016/j.molbrainres.2005.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 05/18/2005] [Accepted: 06/08/2005] [Indexed: 11/29/2022]
Abstract
GABA, the major inhibitory neurotransmitter of the vertebrate brain, has been shown to play an important role in vertebrate reproduction by regulating LH release and sexual behavior. We have studied the expression of the GABA-synthesizing enzyme, glutamic acid decarboxylase (GAD), in goldfish throughout the reproductive cycle in May (mature), November (early gonadal recrudescence) and February (late gonadal recrudescence) and in response to implanted sex steroids. Levels of GAD67 and GAD65 mRNA levels in the hypothalamus of both males and females were highest in the early stages of gonadal recrudescence. In the telencephalon, a different seasonal pattern of GAD expression was evident. The telencephalic expression GAD67, GAD65 and a novel isoform, GAD3, were highest in sexually mature fish in May. Five-day intraperitoneal implantation of gonad-intact fish with testosterone (T), estradiol (E2) or progesterone (P4) did not affect GAD expression in November and February. This is in contrast to results in May when sex differences in steroid responsiveness were evident. Progesterone decreased hypothalamic GAD67 and GAD65 in females and was without effect in males. All other treatments did not alter GAD67, GAD65 or GAD3 expression in the hypothalamus. Both T and P4 decreased GAD67 and GAD65 levels in the telencephalon of male goldfish but had no effect in females. Serum sex steroid levels in control and implanted mature males and females in May were similar so it is unlikely that sex differences in the GAD responses were a result of differences in serum sex steroid levels. These contrasting effects of sex steroids on males and females suggest important sex differences in the regulation of the GADs in sexually mature goldfish.
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Affiliation(s)
- K Larivière
- Department of Biology, Centre for Advanced Research in Environmental Genomics, Canada
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Maharjan S, Serova L, Sabban EL. Transcriptional regulation of tyrosine hydroxylase by estrogen: opposite effects with estrogen receptors alpha and beta and interactions with cyclic AMP. J Neurochem 2005; 93:1502-14. [PMID: 15935066 DOI: 10.1111/j.1471-4159.2005.03142.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Reported effects of estrogen administration on tyrosine hydroxylase (TH) gene expression are confusing. Therefore, we studied the mechanism of regulation of TH transcription by estrogen with different estradiol receptor (ER) subtypes. PC12 cells, transiently co-transfected with expression vector for ERalpha or ERbeta, and luciferase gene under control of the TH promoter, were treated with 17 beta-estradiol (E2). E2 doubled luciferase activity with ERalpha; however, it was decreased with ERbeta. Mapping the TH promoter showed that the putative half estrogen response element (ERE) motif at - 675, as well as the activation protein 1 motif at - 205, were not required for response to E2 with either ER. The specificity protein 1/early growth response gene 1 (Egr 1) motif was required for the E2-elicited response with ERbeta, but not with ERalpha. Deletion of the cyclic AMP/Ca2+ response element (CRE/CaRE) nearly abolished E2-triggered responses with either ER. Further analysis revealed an imperfect canonical putative ERE overlapping with CRE/CaRE and Nurr1 response element. Oligonucleotides spanning this ERE displayed binding to ER, Cyclic AMP Response Element Binding Protein (CREB) and other proteins. Moreover, E2 attenuated the increase in TH transcription seen with cyclic AMP analogs. Thus, TH is transcriptionally regulated by estradiol in opposite directions depending on ER subtype. The overlapping ERE and CRE/CaRE may integrate interactions elicited by various regulators of TH transcription including cAMP and estrogens.
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Affiliation(s)
- Shreekrishna Maharjan
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York 10595, USA
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Luo Q, Ban M, Ando H, Kitahashi T, Kumar Bhandari R, McCormick SD, Urano A. Distinct effects of 4-nonylphenol and estrogen-17 beta on expression of estrogen receptor alpha gene in smolting sockeye salmon. Comp Biochem Physiol C Toxicol Pharmacol 2005; 140:123-30. [PMID: 15792631 DOI: 10.1016/j.cca.2005.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 01/13/2005] [Accepted: 01/17/2005] [Indexed: 10/25/2022]
Abstract
Xenoestrogens such as 4-nonylphenol (4-NP) have been shown to affect the parr-smolt transformation, but their mechanisms of action are not known. We therefore examined effects of 4-NP and estradiol-17beta (E2) on expression of estrogen receptor (ER) alpha gene in the liver, gill, pituitary and brain of sockeye salmon to elucidate molecular mechanisms of 4-NP and E2 and developmental differences in response during smolting. Fish were treated twice within a week with 4-NP (15 and 150 mg/kg BW), E2 (2 mg/kg BW) or only vehicle at three stages of smolting, pre-smolting in March, early smolting in April and late smolting in May. The absolute amounts of ERalpha mRNA were determined by real-time PCR. The basal amounts of ERalpha mRNA peaked in April in the liver, gill and pituitary. In March, E2 extensively increased the amounts in the liver, while 4-NP had no effects at this stage. In contrast, 4-NP (but not E2) decreased liver ERalpha mRNA in April. 4-NP also decreased the amount of ERalpha mRNA in the gill in April. In the pituitary, 4-NP increased ERalpha mRNA in March but decreased it in May. There were no significant effects in the brain. Changes in basal ERalpha mRNA observed in this study indicate that estrogen responsiveness of tissues may change during salmon smolting. Furthermore, 4-NP and E2 have different effects on expression of ERalpha gene in the liver and gill during smolting, and the response is dependent on smolt stage.
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Affiliation(s)
- Qiong Luo
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido, Japan
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Forlano PM, Deitcher DL, Bass AH. Distribution of estrogen receptor alpha mRNA in the brain and inner ear of a vocal fish with comparisons to sites of aromatase expression. J Comp Neurol 2005; 483:91-113. [PMID: 15672394 DOI: 10.1002/cne.20397] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Among vertebrates, teleost fish have the greatest capacity for estrogen production in the brain. Previously, we characterized the distribution of the estrogen-synthesizing enzyme aromatase in the brain of the midshipman fish. Here, we investigated the distribution of estrogen receptor alpha (ERalpha). A partial cDNA of ERalpha was cloned and used to generate midshipman-specific primers for RT and real-time PCR which identified transcripts in liver and ovary, the CNS, and the sensory epithelium of the main auditory endorgan (sacculus). In situ hybridization revealed abundant expression throughout the preoptic area, a vocal-acoustic site in the hypothalamus, amygdala homologs of the dorsal pallium, the pineal organ, the inner ear, the pituitary, and the ovary. Weaker expression was found in the midbrain's nucleus of the medial longitudinal fasciculus and in the dimorphic vocal motor nucleus. ERalpha expression in the pineal, gonad, and pituitary axis may function to time seasonal abiotic cues to reproductive state, while expression in the vocal motor and auditory systems support neurophysiological evidence for estrogen as a modulator of vocal motor and auditory encoding mechanisms in midshipman fish. While ERalpha is restricted to specific nuclei, aromatase expression is abundant in glial cells throughout the entire forebrain, and high in midbrain and hindbrain - spinal vocal regions. The only site of aromatase-containing neurons is in the peripheral auditory system, where it is localized to ganglion cells in the auditory nerve. Estrogen production proximal to ERalpha-positive neurons may provide for focal sites of estrogen effects on reproductive-, vocal-, and auditory-related neurons.
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Affiliation(s)
- Paul M Forlano
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA
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Halm S, Martínez-Rodríguez G, Rodríguez L, Prat F, Mylonas CC, Carrillo M, Zanuy S. Cloning, characterisation, and expression of three oestrogen receptors (ERalpha, ERbeta1 and ERbeta2) in the European sea bass, Dicentrarchus labrax. Mol Cell Endocrinol 2004; 223:63-75. [PMID: 15279912 DOI: 10.1016/j.mce.2004.05.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Revised: 05/17/2004] [Accepted: 05/21/2004] [Indexed: 11/20/2022]
Abstract
Three oestrogen receptor [ER] subtypes have been described in teleost fish, namely ERalpha, and two ERbeta subtypes, called ERbeta1 and ERbeta2 (or ERbeta and ERgamma in Atlantic croaker). Their expression during embryonic development and gonadal growth has evoked interest in their potential role in sexual differentiation and gonadal development in fish. We cloned three oestrogen receptors from adult liver (sb-ERalpha cDNA) and ovary (partial sb-ERbeta1 and sb-ERbeta2 cDNAs) of the European sea bass, and according to their phylogenetic relatedness to other ERs in teleosts, named them sea bass [sb-] ERalpha, ERbeta1 and ERbeta2. Deduced amino acid numbers for sb-ERalpha, sb-ERbeta1 and sb-ERbeta2 were 639, 517 and 608, respectively, representing in the case of sb-ERbeta1 and sb-ERbeta2 about 90% of the open reading frame. Highest amino acid identities were found for sb-ERalpha with eelpout ERalpha (88.7%), for sb-ERbeta1 with Atlantic croaker ERgamma (85.8%), and for sb-ERbeta2 with Atlantic croaker ERbeta (90.1%). Southern analysis confirmed that all three sea bass oestrogen receptors (sb-ERs) are the products of three distinct genes. In adult sea bass, ERalpha was predominantly expressed in liver and pituitary, while sb-ERbeta1 and sb-ERbeta2 were more ubiquitously expressed, with highest expression levels in pituitary. In a mixed-sex population of juvenile sea bass, sb-ERalpha expression was significantly elevated in gonads at 200 days posthatch (dph), while for sb-ERbeta1 and sb-ERbeta2 highest expression levels were observed in gonads at 250 dph. For sb-ERbeta2, expression was also significantly higher in the brain at 250 dph. The cloning of these three ER subtypes in the European sea bass together with the results obtained on expression levels in adult and juvenile animals has given us the foundation to investigate their possible role in sexual differentiation and development in this species in future studies.
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Affiliation(s)
- S Halm
- Instituto de Acuicultura de Torre de la Sal, Consejo Superior de Investigaciones Científicas (CSIC), Ribera de Cabanes, 12595 Torre de la Sal, Spain
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Vetillard A, Bailhache T. Cadmium: an endocrine disrupter that affects gene expression in the liver and brain of juvenile rainbow trout. Biol Reprod 2004; 72:119-26. [PMID: 15317685 DOI: 10.1095/biolreprod.104.029520] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
An inhibition of vitellogenesis is observed in fish exposed to cadmium (Cd), either in natural or in experimental conditions. To investigate whether this correlates or not with modifications in the expression of several genes involved in reproduction, we have performed a study on juvenile rainbow trout (Oncorhynchus mykiss) exposed to waterborne Cd in combination with estradiol (E2). A relative reverse transcription-PCR protocol was used to evaluate the effect of Cd exposure on the expression of several genes. We quantified vitellogenin, rainbow trout estradiol receptor alpha (rtERalpha), short and long isoforms (rtERalphaS and rtERalphaL), mRNA levels in liver, and salmon GnRH1, salmon GnRH2, rtERalphaS, and rtERalphaL mRNA levels in the brain. In liver, Cd reduced the E2-stimulated mRNA levels of vitellogenin as well as these of both rtERalpha isoforms in a dose-dependent manner. In brain tissue, our results indicate that rtERalpha mRNA levels are not enhanced by E2. Cd treatments did not modify rtERalphaS isoform expression but reduced rtERalphaL expression in the brain. Focusing on the expression of salmon GnRH (sGnRH) genes, E2 did not affect mRNA levels, but experiments with Cd alone greatly enhanced sGnRH 1 as well as sGnRH 2 gene expression in a dose-dependant manner. This study supports the idea that Cd is an important endocrine disrupter that could act through an inhibition of E2-stimulated genes in the liver and also through a central effect on sGnRH gene expression. Cd may affect a number of E2 signaling pathways but could also affect the reproductive axis by nonestrogenic mechanisms.
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Affiliation(s)
- Angelique Vetillard
- Endocrinologie Moléculaire de la Reproduction, UMR-CNRS 6026, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes cedex, France.
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Menuet A, Anglade I, Le Guevel R, Pellegrini E, Pakdel F, Kah O. Distribution of aromatase mRNA and protein in the brain and pituitary of female rainbow trout: Comparison with estrogen receptor alpha. J Comp Neurol 2003; 462:180-93. [PMID: 12794742 DOI: 10.1002/cne.10726] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Recent data indicate that estrogens locally produced in the brain by aromatization of androgens could be important for neurogenesis and brain repair. In this respect, fish are interesting because of the extremely high aromatase activity of their brain. In this study, the rainbow trout brain aromatase was cloned and riboprobes were used to map the distribution of cells expressing the corresponding mRNAs. A very strong hybridization signal was detected in the pituitary and in cells bordering the ventricles in the telencephalon and ventral diencephalon, with the highest expression in the preoptic area and hypothalamus. A weaker signal was detected in the ependymal layer bordering the torus semicircularis and optic tectum. This localization was fully confirmed by immunohistochemistry using antibodies against a teleost aromatase. In addition, this antibody showed that aromatase expression in fact corresponds to radial glial cells because immunoreactive cells had long cytoplasmic processes extending toward the pial surface. Because brain aromatase was shown to be upregulated by estradiol in fish, the distribution of aromatase mRNAs was compared with that of rainbow trout estrogen receptor alpha (rtERalpha) on adjacent sections. Although the highest aromatase expression was found in regions expressing rtERalpha, no obvious coexpression was found, as rtERalpha was never observed in radial cells. However, reverse transcriptase-polymerase chain reaction experiments performed on brain cell cultures enriched in glial cells suggest that a weak expression of rtERalpha in glial cells cannot be excluded. The possible role of the high brain aromatase content in fish could be related to the continuous growth of their central nervous system during adulthood.
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Affiliation(s)
- Arnaud Menuet
- Endocrinologie Moléculaire de la Reproduction, UMR CNRS 6026, Campus de Beaulieu, 35042 Rennes cedex, France
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Vacher C, Pellegrini E, Anglade I, Ferriére F, Saligaut C, Kah O. Distribution of dopamine D2 receptor mRNAs in the brain and the pituitary of female rainbow trout: an in situ hybridization study. J Comp Neurol 2003; 458:32-45. [PMID: 12577321 DOI: 10.1002/cne.10545] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The distribution of D(2)R (dopamine D(2) receptor) mRNAs was studied in the forebrain of maturing female rainbow trout by means of in situ hybridization using a (35)S-labeled riboprobe (810 bp) spanning the third intracytoplasmic loop. A hybridization signal was consistently obtained in the olfactory epithelium, the internal cell layer of the olfactory bulbs, the ventral and dorsal subdivisions of the ventral telencephalon, and most preoptic subdivisions, with the notable exception of the magnocellular preoptic nucleus, and the periventricular regions of the mediobasal hypothalamus, including the posterior tuberculum. In the pituitary, the signal was higher in the pars intermedia than in the proximal and the rostral pars distalis, but no obvious correspondence with a given cell type could be assigned. Labeled cells were also located in the thalamic region, some pretectal nuclei, the optic tectum, and the torus semicircularis. These results provide a morphologic basis for a better understanding on the functions and evolution of the dopaminergic systems in lower vertebrates.
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Affiliation(s)
- Coralie Vacher
- Endocrinologie Moléculaire de la Reproduction, UMR CNRS 6026, Campus de Beaulieu, 35042 Rennes cedex, France
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47
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Menuet A, Pellegrini E, Anglade I, Blaise O, Laudet V, Kah O, Pakdel F. Molecular characterization of three estrogen receptor forms in zebrafish: binding characteristics, transactivation properties, and tissue distributions. Biol Reprod 2002; 66:1881-92. [PMID: 12021076 DOI: 10.1095/biolreprod66.6.1881] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
There are two estrogen receptor (ER) subtypes in fish, ERalpha and ERbeta, and increasing evidence that the ERbeta subtype has more than one form. However, there is little information on the characteristics and functional significance of these ERs in adults and during development. Here, we report the cloning and characterization of three functional ER forms, zfERalpha, zfERbeta1, and zfERbeta2, in the zebrafish. The percentages of identity between these receptors suggest the existence of three distinct genes. Each cDNA encoded a protein that specifically bound estradiol with a dissociation constant ranging from 0.4 nM (zfERbeta2) to 0.75 nM (zfERalpha and zfERbeta1). In transiently transfected cells, all three forms were able to induce, in a dose-dependent manner, the expression of a reporter gene driven by a consensus estrogen responsive element; zfERbeta2 was slightly more sensitive than zfERalpha and zfERbeta1. Tissue distribution pattern, analyzed by reverse transcription polymerase chain reaction, showed that the three zfER mRNAs largely overlap and are predominantly expressed in brain, pituitary, liver, and gonads. In situ hybridization was performed to study in more detail the distribution of the three zfER mRNAs in the brain of adult females. The zfER mRNAs exhibit distinct but partially overlapping patterns of expression in two neuroendocrine regions, the preoptic area and the mediobasal hypothalamus. The characterization of these zfERs provides a new perspective for understanding the mechanisms underlying estradiol actions in a vertebrate species commonly used for developmental studies.
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Affiliation(s)
- Arnaud Menuet
- Endocrinologie Moléculaire de la Reproduction, UMR CNRS 6026, Campus de Beaulieu, 35042 Rennes cedex, France
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