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Byun JH, Hyeon JY, Hettiarachchi SA, Udagawa S, Mahardini A, Kim JM, Hur SP, Takemura A. Effects of dopamine and melatonin treatment on the expression of the genes associated with artificially induced sexual maturation in Japanese eel, Anguilla japonica. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:389-399. [PMID: 38334250 DOI: 10.1002/jez.2788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/14/2024] [Accepted: 01/18/2024] [Indexed: 02/10/2024]
Abstract
Japanese eel (Anguilla japonica) is a commercially important fish species in Asia. Understanding factors like photoperiod, temperature, and lunar cycles is crucial for successful aquaculture and managing its reproduction. Melatonin and dopamine (DA) are essential for regulating reproduction in vertebrates, including fish. This study investigated the effects of melatonin and DA on the reproductive system of mature male Japanese eels to better understand reproductive regulation in fish. To clarify the effects of these hormones on sexual maturation in eels, a critical stage in the reproductive process, sexual maturation was induced by injecting human chorionic gonadotropin, which stimulates the production of sex hormones. To check the effect of melatonin and DA on sexual maturation, DA, melatonin, and DA + domperidone were intraperitoneally injected into fish from each group (six per treatment) at a dose of 1 mg/kg body weight. The fish were then examined using quantitative RT-PCR by comparing the messenger RNA level of reproduction-related genes (gonadotropin releasing hormone 1; gnrh1, gonadotropin releasing hormone 2; gnrh2, follicle stimulating hormone; fshβ, luteinizing hormone; lhβ and DA receptor 2b; d2b), involved in the gonadotropic axis in eels, to those that received a control injection. The results indicate significant differences in the expression levels of gnrh1, gnrh2 and d2b in the brain and d2b, fshβ, lhβ in the pituitary at different stages of sexual maturation. Melatonin appears to enhance the production of sex gonadotropins, whereas DA inhibits them. These findings suggest an interaction between melatonin and DA in regulating reproduction in Japanese eels.
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Affiliation(s)
- Jun-Hwan Byun
- Department of Fisheries Biology, College of Fisheries Sciences, Pukyong National University, Busan, South Korea
| | - Ji-Yeon Hyeon
- Division of Polar Life Science, Korea Polar Research Institute, Incheon, South Korea
| | | | - Shingo Udagawa
- Department of Co-Creation Management, Organization for Research Promotion, University of the Ryukyus, Okinawa, Japan
| | - Angka Mahardini
- Department of Marine Science, Faculty of Science, Diponegoro University, Semarang, Indonesia
| | - Jong-Myoung Kim
- Department of Fisheries Biology, College of Fisheries Sciences, Pukyong National University, Busan, South Korea
| | - Sung-Pyo Hur
- Department of Marine Life Science, Jeju National University, Jeju, South Korea
| | - Akihiro Takemura
- Department of Chemistry, Biology, and Marine Science, University of the Ryukyus, Okinawa, Japan
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Kumar M, Goswami M, Nayak SK, Gireesh-Babu P, Chaudhari A. Evaluation of the Binding Affinity of a Gonadotropin-Releasing Hormone
Analogue (GnRH-a) Buserelin through In silico and In vivo Testing in
Clarias magur. CURR PROTEOMICS 2022. [DOI: 10.2174/1570164618666210426090916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aim:
To evaluate the binding affinity and biological potency of gonadotropin-releasing
hormone analogue (GnRHa) Buserelin (C60H86N16O13) based on in silico and in vivo testing for induced
breeding in Clarias magur.
Background:
Many attempts have been made to induce C. magur, but encouraging results have
not yet been achieved. Hence, it is the need of the hour to find out more potent analogues or other
bio-molecules for induced breeding in C. magur to facilitate sustainable aquaculture.
Objective:
To determine the binding affinity of C. magur GnRH receptor through in silico and to
validate it for induced breeding of C. magur.
Methods:
Buserelin (C60H86N16O13) was selected as the potential GnRHa after screening several peptides
for their binding energy with the C. magur GnRH receptor. The induced breeding trial was set
up at ICAR-CIFE Powarkheda Centre, M.P. India, and Buserelin was administered in different doses
to the brooders along with the dopamine inhibitor domperidone. The standard treatment with the
commercial salmon GnRH (sGnRH) analogue Ovaprim® (Syndel, USA) was used as the control.
Results:
The 3-D structure of C. magur GnRH receptor was generated using MODELLER software.
Molecular docking studies revealed the binding preference of the receptor as chicken (c) Gn-
RH-II > Buserelin > sGnRH > catfish (cf) GnRH > human (m) GnRH. Though Buserelin showed
better binding affinity compared to sGnRH, induced breeding experiments with magur showed similar
performance of the ligands at the equivalent dose of 20 μg/kg B.W., but the spontaneous release
of milt from the males was not observed in both cases. Significantly better reproductive parameters
were recorded with Buserelin at the dose of 30 μg/kg B.W.
Conclusion:
The study revealed that that the GnRHa Buserelin can be used as an effective inducing
agent for breeding in C. magur.
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Affiliation(s)
- Mukesh Kumar
- Fish Genetics & Biotechnology Division, ICAR-Central Institute of Fisheries Education, Mumbai - 400 061 India
| | - Mukunda Goswami
- Fish Genetics & Biotechnology Division, ICAR-Central Institute of Fisheries Education, Mumbai - 400 061 India
| | - Sunil Kumar Nayak
- Fish Genetics & Biotechnology Division, ICAR-Central Institute of Fisheries Education, Mumbai - 400 061 India
| | - P. Gireesh-Babu
- Fish Genetics & Biotechnology Division, ICAR-Central Institute of Fisheries Education, Mumbai - 400 061 India
| | - Aparna Chaudhari
- Fish Genetics & Biotechnology Division, ICAR-Central Institute of Fisheries Education, Mumbai - 400 061 India
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Dairaghi L, Constantin S, Oh A, Shostak D, Wray S. The Dopamine D4 Receptor Regulates Gonadotropin-Releasing Hormone Neuron Excitability in Male Mice. eNeuro 2022; 9:ENEURO.0461-21.2022. [PMID: 35165199 PMCID: PMC8896547 DOI: 10.1523/eneuro.0461-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/26/2022] [Accepted: 02/02/2022] [Indexed: 12/30/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH)-secreting neurons control fertility. The release of GnRH peptide regulates the synthesis and release of both luteinizing hormone (LH) and Follicle stimulation hormone (FSH) from the anterior pituitary. While it is known that dopamine regulates GnRH neurons, the specific dopamine receptor subtype(s) involved remain unclear. Previous studies in adult rodents have reported juxtaposition of fibers containing tyrosine hydroxylase (TH), a marker of catecholaminergic cells, onto GnRH neurons and that exogenous dopamine inhibits GnRH neurons postsynaptically through dopamine D1-like and/or D2-like receptors. Our microarray data from GnRH neurons revealed a high level of Drd4 transcripts [i.e., dopamine D4 receptor (D4R)]. Single-cell RT-PCR and immunocytochemistry confirmed GnRH cells express the Drd4 transcript and protein, respectively. Calcium imaging identified changes in GnRH neuronal activity during application of subtype-specific dopamine receptor agonists and antagonists when GABAergic and glutamatergic transmission was blocked. Dopamine, dopamine with D1/5R-specific or D2/3R-specific antagonists or D4R-specific agonists decreased the frequency of calcium oscillations. In contrast, D1/5R-specific agonists increased the frequency of calcium oscillations. The D4R-mediated inhibition was dependent on Gαi/o protein coupling, while the D1/5R-mediated excitation required Gαs protein coupling. Together, these results indicate that D4R plays an important role in the dopaminergic inhibition of GnRH neurons.
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Affiliation(s)
| | | | - Andrew Oh
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke/National Institutes of Health, Bethesda, MD 20892
| | - David Shostak
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke/National Institutes of Health, Bethesda, MD 20892
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Borgonovo J, Ahumada-Galleguillos P, Oñate-Ponce A, Allende-Castro C, Henny P, Concha ML. Organization of the Catecholaminergic System in the Short-Lived Fish Nothobranchius furzeri. Front Neuroanat 2021; 15:728720. [PMID: 34588961 PMCID: PMC8473916 DOI: 10.3389/fnana.2021.728720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/13/2021] [Indexed: 12/02/2022] Open
Abstract
The catecholaminergic system has received much attention based on its regulatory role in a wide range of brain functions and its relevance in aging and neurodegenerative diseases. In the present study, we analyzed the neuroanatomical distribution of catecholaminergic neurons based on tyrosine hydroxylase (TH) immunoreactivity in the brain of adult Nothobranchius furzeri. In the telencephalon, numerous TH+ neurons were observed in the olfactory bulbs and the ventral telencephalic area, arranged as strips extending through the rostrocaudal axis. We found the largest TH+ groups in the diencephalon at the preoptic region level, the ventral thalamus, the pretectal region, the posterior tuberculum, and the caudal hypothalamus. In the dorsal mesencephalic tegmentum, we identified a particular catecholaminergic group. The rostral rhombencephalon housed TH+ cells in the locus coeruleus and the medulla oblongata, distributing in a region dorsal to the inferior reticular formation, the vagal lobe, and the area postrema. Finally, scattered TH+ neurons were present in the ventral spinal cord and the retina. From a comparative perspective, the overall organization of catecholaminergic neurons is consistent with the general pattern reported for other teleosts. However, N. furzeri shows some particular features, including the presence of catecholaminergic cells in the midbrain. This work provides a detailed neuroanatomical map of the catecholaminergic system of N. furzeri, a powerful aging model, also contributing to the phylogenetic understanding of one of the most ancient neurochemical systems.
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Affiliation(s)
- Janina Borgonovo
- Laboratory of Experimental Ontogeny, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | - Patricio Ahumada-Galleguillos
- Laboratory of Experimental Ontogeny, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Santiago, Chile
| | - Alejandro Oñate-Ponce
- Laboratory of Experimental Ontogeny, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | - Camilo Allende-Castro
- Laboratory of Experimental Ontogeny, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | - Pablo Henny
- Department of Anatomy and Interdisciplinary Center of Neurosciences, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Miguel L Concha
- Laboratory of Experimental Ontogeny, Faculty of Medicine, Institute of Biomedical Sciences, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
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5
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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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6
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The stress - Reproductive axis in fish: The involvement of functional neuroanatomical systems in the brain. J Chem Neuroanat 2020; 112:101904. [PMID: 33278567 DOI: 10.1016/j.jchemneu.2020.101904] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/23/2020] [Accepted: 11/30/2020] [Indexed: 01/26/2023]
Abstract
The neuroendocrine-stress axis of nonmammalian species is evolutionarily conserved, which makes them useful to serve as important model systems for elucidating the function of the vertebrate stress response. The involvement of hypothalamo-pituitary-adrenal (HPA) axis hormones in regulation of stress and reproduction is well described in different vertebrates. However, the stress response is a complex process, which appears to be controlled by a number of neurochemicals in association with hypothalamo-pituitary-interrenal (HPI) axis or independent of HPI axis in fish. In recent years, the participation of neurohormones other than HPI axis in regulation of stress and reproduction is gaining more attention. This review mainly focuses on the involvement of functional neuroanatomical systems such as the catecholaminergic neurotransmitter dopamine (DA) and opioid peptides in regulation of the stress-reproductive axis in fish. Occurrences of DA and opioid peptides like β-endorphin, enkephalins, dynorphin, and endomorphins have been demonstrated in fish brain, and diverse roles such as pain modulation, social behaviour and reproduction are implicated for these hormones. Neuroanatomical studies using retrograde tracing, immunohistochemical staining and lesion methods have demonstrated that the neurons originating in the preoptic region and the nucleus lateralis tuberis directly innervate the pituitary gland and, therefore, the hypophysiotrophic role of these hormones. In addition, heightened synthetic and secretory activity of the opioidergic and the dopaminergic neurons in hypothalamic areas of the brain during stress exposure suggest potentially intricate relationship with the stress-reproductive axis in fish. Current evidence in early vertebrates like fish provides a novel insight into the underlying neuroendocrine mechanisms as additional pathways along the stress-reproductive axis that seem to be conserved during the course of evolution.
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7
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Somoza GM, Mechaly AS, Trudeau VL. Kisspeptin and GnRH interactions in the reproductive brain of teleosts. Gen Comp Endocrinol 2020; 298:113568. [PMID: 32710898 DOI: 10.1016/j.ygcen.2020.113568] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/17/2020] [Accepted: 07/19/2020] [Indexed: 02/09/2023]
Abstract
It is well known that gonadotropin-releasing hormone (Gnrh) has a key role in reproduction by regulating the synthesis and release of gonadotropins from the anterior pituitary gland of all vertebrates. About 25 years ago, another neuropeptide, kisspeptin (Kiss1) was discovered as a metastasis suppressor of melanoma cell lines and then found to be essential for mammalian reproduction as a stimulator of hypothalamic Gnrh and regulator of puberty onset. Soon after, a kisspeptin receptor (kissr) was found in the teleost brain. Nowadays, it is known that in most teleosts the kisspeptin system is composed of two ligands, kiss1 and kiss2, and two receptors, kiss2r and kiss3r. Even though both kisspeptin peptides, Kiss1 and Kiss2, have been demonstrated to stimulate gonadotropin synthesis and secretion in different fish species, their actions appear not to be mediated by Gnrh neurons as in mammalian models. In zebrafish and medaka, at least, hypophysiotropic Gnrh neurons do not express Kiss receptors. Furthermore, kisspeptinergic nerve terminals reach luteinizing hormone cells in some fish species, suggesting a direct pituitary action. Recent studies in zebrafish and medaka with targeted mutations of kiss and/or kissr genes reproduce relatively normally. In zebrafish, single gnrh mutants and additionally those having the triple gnrh3 plus 2 kiss mutations can reproduce reasonably well. In these fish, other neuropeptides known to affect gonadotropin secretion were up regulated, suggesting that they may be involved in compensatory responses to maintain reproductive processes. In this context, the present review explores and presents different possibilities of interactions between Kiss, Gnrh and other neuropeptides known to affect reproduction in teleost fish. Our intention is to stimulate a broad discussion on the relative roles of kisspeptin and Gnrh in the control of teleost reproduction.
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Affiliation(s)
- Gustavo M Somoza
- Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Buenos Aires B7130IWA, Argentina.
| | - Alejandro S Mechaly
- Instituto de Investigaciones en Biodiversidad y Biotecnología (CONICET), Mar del Plata, Buenos Aires 7600, Argentina.
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
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8
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Lozano D, Morona R, González A, López JM. Comparative Analysis of the Organization of the Catecholaminergic Systems in the Brain of Holostean Fishes (Actinopterygii/Neopterygii). BRAIN, BEHAVIOR AND EVOLUTION 2019; 93:206-235. [PMID: 31711060 DOI: 10.1159/000503769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/29/2019] [Indexed: 11/19/2022]
Abstract
Living holosteans, comprising 8 species of bowfins and gars, form a small monophyletic group of actinopterygian fishes, which are currently considered as the sister group to the enormously numerous teleosts and have largely been neglected in neuroanatomical studies. We have studied the catecholaminergic (CAergic) systems by means of antibodies against tyrosine hydroxylase (TH) and dopamine (DA) in the brain of representative species of the 3 genera included in the 2 orders of holostean fishes: Amia calva (Amiiformes) and Lepisosteus platyrhincus, Lepisosteus oculatus, and Atractosteus spatula (Lepisosteiformes). Different groups of TH/DA-immunoreactive (ir) cells were observed in the olfactory bulb, subpallium, and preoptic area of the telencephalon. Hypothalamic groups were labeled in the suprachiasmatic nucleus, tuberal (only in A. calva), retrotuberal, and retromamillary areas; specifically, the paraventricular organ showed only DA immunoreactivity. In the diencephalon, TH/DA-ir groups were detected in the prethalamus, posterior tubercle, and pretectum. In the caudal hindbrain, the solitary tract nucleus and area postrema presented TH/DA-ir cell groups, and also the spinal cord and the retina. Only in A. calva, particular CAergic cell groups were observed in the habenula, the mesencephalic tegmentum, and in the locus coeruleus. Following a neuromeric analysis, the comparison of these results with those obtained in other classes of fishes and tetrapods shows many common traits of CAergic systems shared by most vertebrates and in addition highlights unique features of actinopterygian fishes.
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Affiliation(s)
- Daniel Lozano
- Department of Cell Biology, Faculty of Biology, University Complutense, Madrid, Spain
| | - Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense, Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense, Madrid, Spain
| | - Jesús M López
- Department of Cell Biology, Faculty of Biology, University Complutense, Madrid, Spain,
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9
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Giroux M, Vliet SMF, Volz DC, Gan J, Schlenk D. Mechanisms behind interactive effects of temperature and bifenthrin on the predator avoidance behaviors in parr of chinook salmon (Oncorhynchus tshawytscha). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 216:105312. [PMID: 31563086 DOI: 10.1016/j.aquatox.2019.105312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/15/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Many coastal systems have been experiencing the effects of non-chemical and chemical anthropological stressors through respective increases in surface water temperatures and rainstorm-derived runoff events of pyrethroid pesticide movement into waterways such as the San Francisco Bay-Delta. Salmonid populations in the Bay-Delta have been dramatically declining in recent decades. Therefore, the aim of this study was to investigate the interactive effects of bifenthrin, a pyrethroid insecticide, and increasing water temperatures on targeted neuroendocrine and behavioral responses in Chinook salmon (Oncorhynchus tshawytscha) parr (10- month post-hatch). Parr were reared at 11 °C, 16.4 °C, or 19 °C for 14 days and, in the final 96 h of rearing, exposed to nominal concentrations of 0, 0.15, or 1.5 μg/L bifenthrin. A predatory avoidance Y-Maze behavioral assay was conducted immediately following exposures. Parr were presented a choice of clean or odorant zones, and locomotive behavior was recorded. Thyroid hormones (T3 and T4), estradiol, and testosterone were quantified within plasma using ELISAs, and the expression of brain hormone and dopamine receptor genes were also evaluated by qPCR. Brain dopamine levels were analyzed by LC/MS. No significant changes were observed in brain transcripts or plasma hormone concentrations with bifenthrin or increasing temperature. However, temperature did significantly lower brain dopamine levels in fish reared at 19 °C compared to 11 °C controls, but was unaltered by bifenthrin treatment. In contrast, parr reared at 11 °C and exposed to 1.5 μg/L bifenthrin spent significantly less time avoiding a predatory odorant compared to vehicle controls reared at 11 °C. The 16.4 °C and 1.5 μg/L-treated fish spent significantly more time in the neutral arm compared to the odorant and clean arms, as well as spending significantly less time in the clean arm compared to the 11 °C control fish. These results suggest that the interaction of temperature and bifenthrin may be adversely impacting predator-avoidance behavior, which may not be related to dopaminergic responses.
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Affiliation(s)
- Marissa Giroux
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA; Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.
| | - Sara M F Vliet
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA, USA; Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
| | - David C Volz
- Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
| | - Jay Gan
- Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
| | - Daniel Schlenk
- Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
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10
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Maruska KP, Sohn YC, Fernald RD. Mechanistic target of rapamycin (mTOR) implicated in plasticity of the reproductive axis during social status transitions. Gen Comp Endocrinol 2019; 282:113209. [PMID: 31226256 PMCID: PMC6718321 DOI: 10.1016/j.ygcen.2019.113209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/13/2019] [Accepted: 06/17/2019] [Indexed: 01/04/2023]
Abstract
The highly conserved brain-pituitary-gonadal (BPG) axis controls reproduction in all vertebrates, so analyzing the regulation of this signaling cascade is important for understanding reproductive competence. The protein kinase mechanistic target of rapamycin (mTOR) functions as a conserved regulator of cellular growth and metabolism in all eukaryotes, and also regulates the reproductive axis in mammals. However, whether mTOR might also regulate the BPG axis in non-mammalian vertebrates remains unexplored. We used complementary experimental approaches in an African cichlid fish, Astatotilapia burtoni, to demonstrate that mTOR is involved in regulation of the brain, pituitary, and testes when males rise in rank to social dominance. mTOR or downstream components of its signaling pathway (p-p70S6K) were detected in gonadotropin-releasing hormone (GnRH1) neurons, the pituitary, and testes. Transcript levels of mtor in the pituitary and testes also varied when reproductively-suppressed subordinate males rose in social rank to become dominant reproductively-active males, a transition similar to puberty in mammals. Intracerebroventricular injection of the mTORC1 inhibitor, rapamycin, revealed a role for mTOR in the socially-induced hypertrophy of GnRH1 neurons. Rapamycin treatment also had effects at the pituitary and testes, suggesting involvement of the mTORC1 complex at multiple levels of the reproductive axis. Thus, we show that mTOR regulation of BPG function is conserved to fishes, likely playing important roles in regulating reproduction and fertility across all male vertebrates.
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Affiliation(s)
- Karen P Maruska
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, United States.
| | - Young Chang Sohn
- Department of Marine Molecular Bioscience, Gangneung-Wonju National University, Gangneung, Gangwon 25457, Republic of Korea
| | - Russell D Fernald
- Department of Biology, Stanford University, Stanford, CA 94305, United States
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11
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Hilliard AT, Xie D, Ma Z, Snyder MP, Fernald RD. Genome-wide effects of social status on DNA methylation in the brain of a cichlid fish, Astatotilapia burtoni. BMC Genomics 2019; 20:699. [PMID: 31506062 PMCID: PMC6737626 DOI: 10.1186/s12864-019-6047-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/19/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Successful social behavior requires real-time integration of information about the environment, internal physiology, and past experience. The molecular substrates of this integration are poorly understood, but likely modulate neural plasticity and gene regulation. In the cichlid fish species Astatotilapia burtoni, male social status can shift rapidly depending on the environment, causing fast behavioral modifications and a cascade of changes in gene transcription, the brain, and the reproductive system. These changes can be permanent but are also reversible, implying the involvement of a robust but flexible mechanism that regulates plasticity based on internal and external conditions. One candidate mechanism is DNA methylation, which has been linked to social behavior in many species, including A. burtoni. But, the extent of its effects after A. burtoni social change were previously unknown. RESULTS We performed the first genome-wide search for DNA methylation patterns associated with social status in the brains of male A. burtoni, identifying hundreds of Differentially Methylated genomic Regions (DMRs) in dominant versus non-dominant fish. Most DMRs were inside genes supporting neural development, synapse function, and other processes relevant to neural plasticity, and DMRs could affect gene expression in multiple ways. DMR genes were more likely to be transcription factors, have a duplicate elsewhere in the genome, have an anti-sense lncRNA, and have more splice variants than other genes. Dozens of genes had multiple DMRs that were often seemingly positioned to regulate specific splice variants. CONCLUSIONS Our results revealed genome-wide effects of A. burtoni social status on DNA methylation in the brain and strongly suggest a role for methylation in modulating plasticity across multiple biological levels. They also suggest many novel hypotheses to address in mechanistic follow-up studies, and will be a rich resource for identifying the relationships between behavioral, neural, and transcriptional plasticity in the context of social status.
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Affiliation(s)
| | - Dan Xie
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Zhihai Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Michael P. Snyder
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
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12
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Dodd LD, Nowak E, Lange D, Parker CG, DeAngelis R, Gonzalez JA, Rhodes JS. Active feminization of the preoptic area occurs independently of the gonads in Amphiprion ocellaris. Horm Behav 2019; 112:65-76. [PMID: 30959023 DOI: 10.1016/j.yhbeh.2019.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 12/20/2022]
Abstract
Sex differences in the anatomy and physiology of the vertebrate preoptic area (POA) arise during development, and influence sex-specific reproductive functions later in life. Relative to masculinization, mechanisms for feminization of the POA are not well understood. The purpose of this study was to induce sex change from male to female in the anemonefish Amphiprion ocellaris, and track the timing of changes in POA cytoarchitecture, composition of the gonads and circulating sex steroid levels. Reproductive males were paired together and then sampled after 3 weeks, 6 months, 1 year and 3 years. Results show that as males change sex into females, number of medium cells in the anterior POA (parvocellular region) approximately double to female levels over the course of several months to 1 year. Feminization of gonads, and plasma sex steroids occur independently, on a variable timescale, up to years after POA sex change has completed. Findings suggest the process of POA feminization is orchestrated by factors originating from within the brain as opposed to being cued from the gonads, consistent with the dominant hypothesis in mammals. Anemonefish provide an opportunity to explore active mechanisms responsible for female brain development in an individual with male gonads and circulating sex steroid levels.
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Affiliation(s)
- Logan D Dodd
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Ewelina Nowak
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Dominica Lange
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Coltan G Parker
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Ross DeAngelis
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Jose A Gonzalez
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA
| | - Justin S Rhodes
- Department of Psychology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana, Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA.
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13
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López JM, Lozano D, Morona R, González A. Organization of the catecholaminergic systems in two basal actinopterygian fishes, Polypterus senegalus
and Erpetoichthys calabaricus
(Actinopterygii: Cladistia). J Comp Neurol 2018; 527:437-461. [DOI: 10.1002/cne.24548] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/04/2018] [Accepted: 09/23/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Jesús M. López
- Department of Cell Biology, Faculty of Biology; University Complutense of Madrid; Madrid Spain
| | - Daniel Lozano
- Department of Cell Biology, Faculty of Biology; University Complutense of Madrid; Madrid Spain
| | - Ruth Morona
- Department of Cell Biology, Faculty of Biology; University Complutense of Madrid; Madrid Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology; University Complutense of Madrid; Madrid Spain
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14
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Faykoo-Martinez M, Monks DA, Zovkic IB, Holmes MM. Sex- and brain region-specific patterns of gene expression associated with socially-mediated puberty in a eusocial mammal. PLoS One 2018; 13:e0193417. [PMID: 29474488 PMCID: PMC5825099 DOI: 10.1371/journal.pone.0193417] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/09/2018] [Indexed: 12/13/2022] Open
Abstract
The social environment can alter pubertal timing through neuroendocrine mechanisms that are not fully understood; it is thought that stress hormones (e.g., glucocorticoids or corticotropin-releasing hormone) influence the hypothalamic-pituitary-gonadal axis to inhibit puberty. Here, we use the eusocial naked mole-rat, a unique species in which social interactions in a colony (i.e. dominance of a breeding female) suppress puberty in subordinate animals. Removing subordinate naked mole-rats from this social context initiates puberty, allowing for experimental control of pubertal timing. The present study quantified gene expression for reproduction- and stress-relevant genes acting upstream of gonadotropin-releasing hormone in brain regions with reproductive and social functions in pre-pubertal, post-pubertal, and opposite sex-paired animals (which are in various stages of pubertal transition). Results indicate sex differences in patterns of neural gene expression. Known functions of genes in brain suggest stress as a key contributing factor in regulating male pubertal delay. Network analysis implicates neurokinin B (Tac3) in the arcuate nucleus of the hypothalamus as a key node in this pathway. Results also suggest an unappreciated role for the nucleus accumbens in regulating puberty.
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Affiliation(s)
| | - D. Ashley Monks
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Iva B. Zovkic
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Melissa M. Holmes
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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15
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Lee SLJ, Horsfield JA, Black MA, Rutherford K, Fisher A, Gemmell NJ. Histological and transcriptomic effects of 17α-methyltestosterone on zebrafish gonad development. BMC Genomics 2017; 18:557. [PMID: 28738802 PMCID: PMC5523153 DOI: 10.1186/s12864-017-3915-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/28/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Sex hormones play important roles in teleost ovarian and testicular development. In zebrafish, ovarian differentiation appears to be dictated by an oocyte-derived signal via Cyp19a1a aromatase-mediated estrogen production. Androgens and aromatase inhibitors can induce female-to-male sex reversal, however, the mechanisms underlying gonadal masculinisation are poorly understood. We used histological analyses together with RNA sequencing to characterise zebrafish gonadal transcriptomes and investigate the effects of 17α-methyltestosterone on gonadal differentiation. RESULTS At a morphological level, 17α-methyltestosterone (MT) masculinised gonads and accelerated spermatogenesis, and these changes were paralleled in masculinisation and de-feminisation of gonadal transcriptomes. MT treatment upregulated expression of genes involved in male sex determination and differentiation (amh, dmrt1, gsdf and wt1a) and those involved in 11-oxygenated androgen production (cyp11c1 and hsd11b2). It also repressed expression of ovarian development and folliculogenesis genes (bmp15, gdf9, figla, zp2.1 and zp3b). Furthermore, MT treatment altered epigenetic modification of histones in zebrafish gonads. Contrary to expectations, higher levels of cyp19a1a or foxl2 expression in control ovaries compared to MT-treated testes and control testes were not statistically significant during early gonad development (40 dpf). CONCLUSION Our study suggests that both androgen production and aromatase inhibition are important for androgen-induced gonadal masculinisation and natural testicular differentiation in zebrafish.
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Affiliation(s)
| | - Julia A. Horsfield
- Department of Pathology, University of Otago, Dunedin, Otago New Zealand
| | - Michael A. Black
- Department of Biochemistry, University of Otago, Dunedin, Otago New Zealand
| | - Kim Rutherford
- Department of Anatomy, University of Otago, Dunedin, Otago New Zealand
| | - Amanda Fisher
- Department of Pathology, University of Otago, Dunedin, Otago New Zealand
| | - Neil J. Gemmell
- Department of Anatomy, University of Otago, Dunedin, Otago New Zealand
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