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Li M, Yang L, Zhang L, Zhang Q, Liu Y. Specific biomarkers and neurons distribution of different brain regions in largemouth bass ( Micropterus salmoides). Front Endocrinol (Lausanne) 2024; 15:1385575. [PMID: 38745953 PMCID: PMC11091468 DOI: 10.3389/fendo.2024.1385575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024] Open
Abstract
The brain regulates multiple physiological processes in fish. Despite this, knowledge about the basic structure and function of distinct brain regions in non-model fish species remains limited due to their diversity and the scarcity of common biomarkers. In the present study, four major brain parts, the telencephalon, diencephalon, mesencephalon and rhombencephalon, were isolated in largemouth bass, Micropterus salmoides. Within these parts, nine brain regions and 74 nuclei were further identified through morphological and cytoarchitectonic analysis. Transcriptome analysis revealed a total of 7153 region-highly expressed genes and 176 region-specifically expressed genes. Genes related to growth, reproduction, emotion, learning, and memory were significantly overexpressed in the olfactory bulb and telencephalon (OBT). Feeding and stress-related genes were in the hypothalamus (Hy). Visual system-related genes were predominantly enriched in the optic tectum (OT), while vision and hearing-related genes were widely expressed in the cerebellum (Ce) region. Sensory input and motor output-related genes were in the medulla oblongata (Mo). Osmoregulation, stress response, sleep/wake cycles, and reproduction-related genes were highly expressed in the remaining brain (RB). Three candidate marker genes were further identified for each brain regions, such as neuropeptide FF (npff) for OBT, pro-melanin-concentrating hormone (pmch) for Hy, vesicular inhibitory amino acid transporter (viaat) for OT, excitatory amino acid transporter 1 (eaat1) for Ce, peripherin (prph) for Mo, and isotocin neurophysin (itnp) for RB. Additionally, the distribution of seven neurotransmitter-type neurons and five types of non-neuronal cells across different brain regions were analyzed by examining the expression of their marker genes. Notably, marker genes for glutamatergic and GABAergic neurons showed the highest expression levels across all brain regions. Similarly, the marker gene for radial astrocytes exhibited high expression compared to other markers, while those for microglia were the least expressed. Overall, our results provide a comprehensive overview of the structural and functional characteristics of distinct brain regions in the largemouth bass, which offers a valuable resource for understanding the role of central nervous system in regulating physiological processes in teleost.
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Affiliation(s)
- Meijia Li
- College of Biosystems Engineering and Food Science (BEFS), Zhejiang University, Hangzhou, China
| | - Leshan Yang
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, China
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, China
| | - Lei Zhang
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, China
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, China
| | - Qian Zhang
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, China
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, China
| | - Ying Liu
- College of Biosystems Engineering and Food Science (BEFS), Zhejiang University, Hangzhou, China
- Key Laboratory of Environment Controlled Aquaculture, Ministry of Education, Dalian, China
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Opinion AGR, Vanhomwegen M, De Boeck G, Aerts J. Long-term stress induced cortisol downregulation, growth reduction and cardiac remodeling in Atlantic salmon. J Exp Biol 2023; 226:jeb246504. [PMID: 37921456 PMCID: PMC10690108 DOI: 10.1242/jeb.246504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/19/2023] [Indexed: 11/04/2023]
Abstract
Stress and elevated plasma cortisol in salmonids have been linked with pathological remodeling of the heart and deterioration of fitness and welfare. However, these associations were based on biomarkers that fail to provide a retrospective view of stress. This study is the first whereby the association of long-term stress, using scale cortisol as a chronic stress biomarker, with cardiac morphology and growth performance of wild Atlantic salmon (Salmo salar) is made. Growth, heart morphology, plasma and scale cortisol levels, and expression of genes involved in cortisol regulation of the hypothalamic-pituitary-interrenal axis of undisturbed fish (control) were compared with those of fish exposed daily to stress for 8 weeks. Though scale cortisol levels showed a time-dependent accumulation in both groups, plasma and scale cortisol levels of stress group fish were 29.1% and 25.0% lower than those of control fish, respectively. These results correlated with the overall upregulation of stress-axis genes involved in the systemic negative feedback of cortisol, and local feedback via 11β-hydroxysteroid dehydrogenases, glucocorticoid and mineralocorticoid receptors in the stress treatment at the hypothalamus and pituitary level. These lower cortisol levels were, however, counterintuitive in terms of the growth performance as stress group fish grew 33.7% slower than control fish, which probably influenced the 8.4% increase in relative ventricle mass in the stress group. Though compact myocardium area between the treatments was comparable, these parameters showed significant linear correlations with scale cortisol levels, indicating the involvement of chronic stress in cardiac remodeling. These findings underscore the importance of scale cortisol as biomarker when associating chronic stress with long-term processes including cardiac remodeling.
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Affiliation(s)
- April Grace R. Opinion
- University of Antwerp, Department of Biology, ECOSPHERE, 2020 Antwerp, Belgium
- Ghent University, Department of Biology, Stress Physiology Research Group (StressChron), 8400 Ostend, Belgium
| | - Marine Vanhomwegen
- Ghent University, Department of Biology, Stress Physiology Research Group (StressChron), 8400 Ostend, Belgium
| | - Gudrun De Boeck
- University of Antwerp, Department of Biology, ECOSPHERE, 2020 Antwerp, Belgium
| | - Johan Aerts
- Ghent University, Department of Biology, Stress Physiology Research Group (StressChron), 8400 Ostend, Belgium
- Flanders Research Institute for Agriculture, Fisheries and Food, Animal Sciences Unit, Stress Physiology Research Group (StressChron), 8400 Ostend, Belgium
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Link K, Shved N, Serrano N, Akgül G, Caelers A, Faass O, Mouttet F, Raabe O, D’Cotta H, Baroiller JF, Eppler E. Effects of seawater and freshwater challenges on the Gh/Igf system in the saline-tolerant blackchin tilapia (Sarotherodon melanotheron). Front Endocrinol (Lausanne) 2022; 13:976488. [PMID: 36313755 PMCID: PMC9596810 DOI: 10.3389/fendo.2022.976488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Prolactin (Prl) and growth hormone (Gh) as well as insulin-like growth factor 1 (Igf1) are involved in the physiological adaptation of fish to varying salinities. The Igfs have been also ascribed other physiological roles during development, growth, reproduction and immune regulation. However, the main emphasis in the investigation of osmoregulatory responses has been the endocrine, liver-derived Igf1 route and local regulation within the liver and osmoregulatory organs. Few studies have focused on the impact of salinity alterations on the Gh/Igf-system within the neuroendocrine and immune systems and particularly in a salinity-tolerant species, such as the blackchin tilapia Sarotherodon melanotheron. This species is tolerant to hypersalinity and saline variations, but it is confronted by severe climate changes in the Saloum inverse estuary. Here we investigated bidirectional effects of increased salinity followed by its decrease on the gene regulation of prl, gh, igf1, igf2, Gh receptor and the tumor-necrosis factor a. A mixed population of sexually mature 14-month old blackchin tilapia adapted to freshwater were first exposed to seawater for one week and then to fresh water for another week. Brain, pituitary, head kidney and spleen were excised at 4 h, 1, 2, 3 and 7 days after both exposures and revealed differential expression patterns. This investigation should give us a better understanding of the role of the Gh/Igf system within the neuroendocrine and immune organs and the impact of bidirectional saline challenges on fish osmoregulation in non-osmoregulatory organs, notably the complex orchestration of growth factors and cytokines.
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Affiliation(s)
- Karl Link
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Natallia Shved
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Nabil Serrano
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Gülfirde Akgül
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
| | - Antje Caelers
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
| | - Oliver Faass
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
| | | | - Oksana Raabe
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Helena D’Cotta
- Institut des Sciences de l’Evolution de Montpellier (ISEM), Université Montpellier, Institut de Recherche pour le Développement (the French National Research Institute for Sustainable Development) (IRD), Ecole Pratique des Hautes Etudes (Practical School of Advanced Studies) (EPHE), Centre National de la Recherche Scientifique (French National Centre for Scientific Research) (CNRS), Unité Mixte de Recherche (Mixed Research Unit) (UMR) 5554, Montpellier, France
- UMR116-Institut des Sciences de l’Evolution de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France
| | - Jean-François Baroiller
- Institut des Sciences de l’Evolution de Montpellier (ISEM), Université Montpellier, Institut de Recherche pour le Développement (the French National Research Institute for Sustainable Development) (IRD), Ecole Pratique des Hautes Etudes (Practical School of Advanced Studies) (EPHE), Centre National de la Recherche Scientifique (French National Centre for Scientific Research) (CNRS), Unité Mixte de Recherche (Mixed Research Unit) (UMR) 5554, Montpellier, France
- UMR116-Institut des Sciences de l’Evolution de Montpellier, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France
| | - Elisabeth Eppler
- Institute of Anatomy, University of Zurich, Zürich, Switzerland
- Institute of Evolutionary Medicine IEM, University of Zürich, Zürich, Switzerland
- Institute of Anatomy, University of Bern, Bern, Switzerland
- *Correspondence: Elisabeth Eppler,
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