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Alunni A, Pierre C, Torres-Paz J, Clairet N, Langlumé A, Pavie M, Escoffier-Pirouelle T, Leblanc M, Blin M, Rétaux S. An Astyanax mexicanus mao knockout line uncovers the developmental roles of monoamine homeostasis in fish brain. Dev Growth Differ 2023; 65:517-533. [PMID: 37843474 DOI: 10.1111/dgd.12896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/05/2023] [Accepted: 10/12/2023] [Indexed: 10/17/2023]
Abstract
Monoaminergic systems are conserved in vertebrates, yet they present variations in neuroanatomy, genetic components and functions across species. MonoAmine Oxidase, or MAO, is the enzyme responsible for monoamine degradation. While mammals possess two genes, MAO-A and MAO-B, fish possess one single mao gene. To study the function of MAO and monoamine homeostasis on fish brain development and physiology, here we have generated a mao knockout line in Astyanax mexicanus (surface fish), by CRISPR/Cas9 technology. Homozygote mao knockout larvae died at 13 days post-fertilization. Through a time-course analysis, we report that hypothalamic serotonergic neurons undergo fine and dynamic regulation of serotonin level upon loss of mao function, in contrast to those in the raphe, which showed continuously increased serotonin levels - as expected. Dopaminergic neurons were not affected by mao loss-of-function. At behavioral level, knockout fry showed a transient decrease in locomotion that followed the variations in the hypothalamus serotonin neuronal levels. Finally, we discovered a drastic effect of mao knockout on brain progenitors proliferation in the telencephalon and hypothalamus, including a reduction in the number of proliferative cells and an increase of the cell cycle length. Altogether, our results show that MAO has multiple and varied effects on Astyanax mexicanus brain development. Mostly, they bring novel support to the idea that serotonergic neurons in the hypothalamus and raphe of the fish brain are different in nature and identity, and they unravel a link between monoaminergic homeostasis and brain growth.
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Affiliation(s)
- Alessandro Alunni
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Constance Pierre
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Jorge Torres-Paz
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Natacha Clairet
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Auriane Langlumé
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Marie Pavie
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | | | - Michael Leblanc
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Maryline Blin
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, Saclay, France
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2
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Brożko N, Baggio S, Lipiec MA, Jankowska M, Szewczyk ŁM, Gabriel MO, Chakraborty C, Ferran JL, Wiśniewska MB. Genoarchitecture of the Early Postmitotic Pretectum and the Role of Wnt Signaling in Shaping Pretectal Neurochemical Anatomy in Zebrafish. Front Neuroanat 2022; 16:838567. [PMID: 35356436 PMCID: PMC8959918 DOI: 10.3389/fnana.2022.838567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/26/2022] [Indexed: 01/10/2023] Open
Abstract
The pretectum has a distinct nuclear arrangement and complex neurochemical anatomy. While previous genoarchitectural studies have described rostrocaudal and dorsoventral progenitor domains and subdomains in different species, the relationship between these early partitions and its later derivatives in the mature anatomy is less understood. The signals and transcription factors that control the establishment of pretectal anatomy are practically unknown. We investigated the possibility that some aspects of the development of pretectal divisions are controlled by Wnt signaling, focusing on the transitional stage between neurogenesis and histogenesis in zebrafish. Using several molecular markers and following the prosomeric model, we identified derivatives from each rostrocaudal pretectal progenitor domain and described the localization of gad1b-positive GABAergic and vglut2.2-positive glutamatergic cell clusters. We also attempted to relate these clusters to pretectal nuclei in the mature brain. Then, we examined the influence of Wnt signaling on the size of neurochemically distinctive pretectal areas, using a chemical inhibitor of the Wnt pathway and the CRISPR/Cas9 approach to knock out genes that encode the Wnt pathway mediators, Lef1 and Tcf7l2. The downregulation of the Wnt pathway led to a decrease in two GABAergic clusters and an expansion of a glutamatergic subregion in the maturing pretectum. This revealed an instructive role of the Wnt signal in the development of the pretectum during neurogenesis. The molecular anatomy presented here improves our understanding of pretectal development during early postmitotic stages and support the hypothesis that Wnt signaling is involved in shaping the neurochemical organization of the pretectum.
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Affiliation(s)
- Nikola Brożko
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Suelen Baggio
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Marcin A. Lipiec
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Marta Jankowska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | | | | | | | - José L. Ferran
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Institute of Biomedical Research of Murcia -Ű IMIB, Virgen de la Arrixaca University Hospital, Murcia, Spain
| | - Marta B. Wiśniewska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- *Correspondence: Marta B. Wiśniewska,
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3
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Westphal M, Panza P, Kastenhuber E, Wehrle J, Driever W. Wnt/β-catenin signaling promotes neurogenesis in the diencephalospinal dopaminergic system of embryonic zebrafish. Sci Rep 2022; 12:1030. [PMID: 35046434 PMCID: PMC8770493 DOI: 10.1038/s41598-022-04833-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/28/2021] [Indexed: 12/21/2022] Open
Abstract
Wnt/β-catenin signaling contributes to patterning, proliferation, and differentiation throughout vertebrate neural development. Wnt/β-catenin signaling is important for mammalian midbrain dopaminergic neurogenesis, while little is known about its role in ventral forebrain dopaminergic development. Here, we focus on the A11-like, Otp-dependent diencephalospinal dopaminergic system in zebrafish. We show that Wnt ligands, receptors and extracellular antagonist genes are expressed in the vicinity of developing Otp-dependent dopaminergic neurons. Using transgenic Wnt/β-catenin-reporters, we found that Wnt/β-catenin signaling activity is absent from these dopaminergic neurons, but detected Wnt/β-catenin activity in cells adjacent to the caudal DC5/6 clusters of Otp-dependent dopaminergic neurons. Pharmacological manipulations of Wnt/β-catenin signaling activity, as well as heat-shock driven overexpression of Wnt agonists and antagonists, interfere with the development of DC5/6 dopaminergic neurons, such that Wnt/β-catenin activity positively correlates with their number. Wnt/β-catenin activity promoted dopaminergic development specifically at stages when DC5/6 dopaminergic progenitors are in a proliferative state. Our data suggest that Wnt/β-catenin signaling acts in a spatially and temporally restricted manner on proliferative dopaminergic progenitors in the hypothalamus to positively regulate the size of the dopaminergic neuron groups DC5 and DC6.
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Affiliation(s)
- Markus Westphal
- Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany.,CIBSS and BIOSS-Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany
| | - Paolo Panza
- Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany.,Department of Developmental Genetics, Max-Planck-Institute for Heart and Lung Research, Ludwigstraße 43, 61231, Bad Nauheim, Germany
| | - Edda Kastenhuber
- Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany.,Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Johanna Wehrle
- Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany.,CIBSS and BIOSS-Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany
| | - Wolfgang Driever
- Developmental Biology, Faculty of Biology, Institute Biology 1, Albert Ludwigs University Freiburg, Hauptstrasse 1, 79104, Freiburg, Germany. .,CIBSS and BIOSS-Centres for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany.
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4
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nr0b1 (DAX1) loss of function in zebrafish causes hypothalamic defects via abnormal progenitor proliferation and differentiation. J Genet Genomics 2021; 49:217-229. [PMID: 34606992 DOI: 10.1016/j.jgg.2021.08.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 11/23/2022]
Abstract
The nuclear receptor DAX-1 (encoded by the NR0B1 gene) is presented in the hypothalamic tissues in humans and other vertebrates. Human patients with NR0B1 mutations often have hypothalamic-pituitary defects, but the involvement of NR0B1 in hypothalamic development and function is not well understood. Here, we report the disruption of the nr0b1 gene in zebrafish causes abnormal expression of gonadotropins, a reduction in fertilization rate, and an increase in post-fasting food intake, which is indicative of abnormal hypothalamic functions. We find that loss of nr0b1 increases the number of prodynorphin (pdyn)-expressing neurons but decreases the number of pro-opiomelanocortin (pomcb)-expressing neurons in the zebrafish hypothalamic arcuate region (ARC). Further examination reveals that the proliferation of progenitor cells is reduced in the hypothalamus of nr0b1 mutant embryos accompanying with the decreased expression of genes in the Notch signaling pathway. Additionally, the inhibition of Notch signaling in wild-type embryos increases the number of pdyn neurons, mimicking the nr0b1 mutant phenotype. In contrast, ectopic activation of Notch signaling in nr0b1 mutant embryos decreases the number of pdyn neurons. Taken together, our results suggest that nr0b1 regulates neural progenitor proliferation and maintenance to ensure normal hypothalamic neuron development.
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5
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Umans RA, Ten Kate M, Pollock C, Sontheimer H. Fishing for Contact: Modeling Perivascular Glioma Invasion in the Zebrafish Brain. ACS Pharmacol Transl Sci 2021; 4:1295-1305. [PMID: 34423267 DOI: 10.1021/acsptsci.0c00129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Indexed: 12/16/2022]
Abstract
Glioblastoma multiforme (GBM) is a highly invasive, central nervous system (CNS) cancer for which there is no cure. Invading tumor cells evade treatment, limiting the efficacy of the current standard of care regimen. Understanding the underlying invasive behaviors that support tumor growth may allow for generation of novel GBM therapies. Zebrafish (Danio rerio) are attractive for genetics and live imaging and have, in recent years, emerged as a model system suitable for cancer biology research. While other groups have studied CNS tumors using zebrafish, few have concentrated on the invasive behaviors supporting the development of these diseases. Previous studies demonstrated that one of the main mechanisms of GBM invasion is perivascular invasion, i.e., single tumor cell migration along blood vessels. Here, we characterize phenotypes, methodology, and potential therapeutic avenues for utilizing zebrafish to model perivascular GBM invasion. Using patient-derived xenolines or an adherent cell line, we demonstrate tumor expansion within the zebrafish brain. Within 24-h postintracranial injection, D54-MG-tdTomato glioma cells produce fingerlike projections along the zebrafish brain vasculature. As few as 25 GBM cells were sufficient to promote single cell vessel co-option. Of note, these tumor-vessel interactions are CNS specific and do not occur on pre-existing blood vessels when injected into the animal's peripheral tissue. Tumor-vessel interactions increase over time and can be pharmacologically disrupted through inhibition of Wnt signaling. Therefore, zebrafish serve as a favorable model system to study perivascular glioma invasion, one of the deadly characteristics that make GBM so difficult to treat.
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Affiliation(s)
- Robyn A Umans
- Center for Glial Biology in Health, Disease, and Cancer, The Fralin Biomedical Research Institute at VTC, Roanoke, Virginia 24016, United States
| | - Mattie Ten Kate
- School of Neuroscience, Virginia Tech, Sandy Hall, 210 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Carolyn Pollock
- School of Neuroscience, Virginia Tech, Sandy Hall, 210 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Harald Sontheimer
- Center for Glial Biology in Health, Disease, and Cancer, The Fralin Biomedical Research Institute at VTC, Roanoke, Virginia 24016, United States.,School of Neuroscience, Virginia Tech, Sandy Hall, 210 Drillfield Drive, Blacksburg, Virginia 24061, United States
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6
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Narumi R, Liu S, Ikeda N, Morita O, Tasaki J. Chemical-Induced Cleft Palate Is Caused and Rescued by Pharmacological Modulation of the Canonical Wnt Signaling Pathway in a Zebrafish Model. Front Cell Dev Biol 2020; 8:592967. [PMID: 33381503 PMCID: PMC7767894 DOI: 10.3389/fcell.2020.592967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 11/02/2020] [Indexed: 11/13/2022] Open
Abstract
Cleft palate is one of the most frequent birth defects worldwide. It causes severe problems regarding eating and speaking and requires long-term treatment. Effective prenatal treatment would contribute to reducing the risk of cleft palate. The canonical Wnt signaling pathway is critically involved in palatogenesis, and genetic or chemical disturbance of this signaling pathway leads to cleft palate. Presently, preventative treatment for cleft palate during prenatal development has limited efficacy, but we expect that zebrafish will provide a useful high-throughput chemical screening model for effective prevention. To achieve this, the zebrafish model should recapitulate cleft palate development and its rescue by chemical modulation of the Wnt pathway. Here, we provide proof of concept for a zebrafish chemical screening model. Zebrafish embryos were treated with 12 chemical reagents known to induce cleft palate in mammals, and all 12 chemicals induced cleft palate characterized by decreased proliferation and increased apoptosis of palatal cells. The cleft phenotype was enhanced by combinatorial treatment with Wnt inhibitor and teratogens. Furthermore, the expression of tcf7 and lef1 as a readout of the pathway was decreased. Conversely, cleft palate was prevented by Wnt agonist and the cellular defects were also prevented. In conclusion, we provide evidence that chemical-induced cleft palate is caused by inhibition of the canonical Wnt pathway. Our results indicate that this zebrafish model is promising for chemical screening for prevention of cleft palate as well as modulation of the Wnt pathway as a therapeutic target.
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Affiliation(s)
- Rika Narumi
- R&D, Safety Science Research, Kao Corporation, Kawasaki, Japan
| | - Shujie Liu
- R&D, Safety Science Research, Kao Corporation, Ichikai-machi, Japan
| | - Naohiro Ikeda
- R&D, Safety Science Research, Kao Corporation, Kawasaki, Japan
| | - Osamu Morita
- R&D, Safety Science Research, Kao Corporation, Ichikai-machi, Japan
| | - Junichi Tasaki
- R&D, Safety Science Research, Kao Corporation, Kawasaki, Japan
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7
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Hedgehog Signaling Regulates Neurogenesis in the Larval and Adult Zebrafish Hypothalamus. eNeuro 2020; 7:ENEURO.0226-20.2020. [PMID: 33106384 PMCID: PMC7769882 DOI: 10.1523/eneuro.0226-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022] Open
Abstract
Neurogenesis is now known to play a role in adult hypothalamic function, yet the cell-cell mechanisms regulating this neurogenesis remain poorly understood. Here, we show that Hedgehog (Hh)/Gli signaling positively regulates hypothalamic neurogenesis in both larval and adult zebrafish and is necessary and sufficient for normal hypothalamic proliferation rates. Hh-responsive radial glia represent a relatively highly proliferative precursor population that gives rise to dopaminergic, serotonergic, and GABAergic neurons. In situ and transgenic reporter analyses revealed substantial heterogeneity in cell-cell signaling within the hypothalamic niche, with slow cycling Nestin-expressing cells residing among distinct and overlapping populations of Sonic Hh (Shh)-expressing, Hh-responsive, Notch-responsive, and Wnt-responsive radial glia. This work shows for the first time that Hh/Gli signaling is a key component of the complex cell-cell signaling environment that regulates hypothalamic neurogenesis throughout life.
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8
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Reuter I, Jäckels J, Kneitz S, Kuper J, Lesch KP, Lillesaar C. Fgf3 is crucial for the generation of monoaminergic cerebrospinal fluid contacting cells in zebrafish. Biol Open 2019; 8:bio.040683. [PMID: 31036752 PMCID: PMC6602327 DOI: 10.1242/bio.040683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In most vertebrates, including zebrafish, the hypothalamic serotonergic cerebrospinal fluid-contacting (CSF-c) cells constitute a prominent population. In contrast to the hindbrain serotonergic neurons, little is known about the development and function of these cells. Here, we identify fibroblast growth factor (Fgf)3 as the main Fgf ligand controlling the ontogeny of serotonergic CSF-c cells. We show that fgf3 positively regulates the number of serotonergic CSF-c cells, as well as a subset of dopaminergic and neuroendocrine cells in the posterior hypothalamus via control of proliferation and cell survival. Further, expression of the ETS-domain transcription factor etv5b is downregulated after fgf3 impairment. Previous findings identified etv5b as critical for the proliferation of serotonergic progenitors in the hypothalamus, and therefore we now suggest that Fgf3 acts via etv5b during early development to ultimately control the number of mature serotonergic CSF-c cells. Moreover, our analysis of the developing hypothalamic transcriptome shows that the expression of fgf3 is upregulated upon fgf3 loss-of-function, suggesting activation of a self-compensatory mechanism. Together, these results highlight Fgf3 in a novel context as part of a signalling pathway of critical importance for hypothalamic development. Summary: This study highlights Fgf3 in a novel context where it is part of a signalling pathway of critical importance for development of hypothalamic monoaminergic cells in zebrafish.
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Affiliation(s)
- Isabel Reuter
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Germany.,Department of Physiological Chemistry, Biocenter, Am Hubland, University of Würzburg, Germany
| | - Jana Jäckels
- Department of Physiological Chemistry, Biocenter, Am Hubland, University of Würzburg, Germany
| | - Susanne Kneitz
- Department of Physiological Chemistry, Biocenter, Am Hubland, University of Würzburg, Germany
| | - Jochen Kuper
- Structural Biology, Rudolf Virchow Center for Biomedical Research, University of Würzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Germany.,Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Department of Neuroscience, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
| | - Christina Lillesaar
- Department of Physiological Chemistry, Biocenter, Am Hubland, University of Würzburg, Germany .,Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, Germany
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9
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Ma L, Wang Y, Hui Y, Du Y, Chen Z, Feng H, Zhang S, Li N, Song J, Fang Y, Xu X, Shi L, Zhang B, Cheng J, Zhou S, Liu L, Zhang X. WNT/NOTCH Pathway Is Essential for the Maintenance and Expansion of Human MGE Progenitors. Stem Cell Reports 2019; 12:934-949. [PMID: 31056478 PMCID: PMC6524734 DOI: 10.1016/j.stemcr.2019.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 12/18/2022] Open
Abstract
Medial ganglionic eminence (MGE)-like cells yielded from human pluripotent stem cells (hPSCs) hold great potentials for cell therapies of related neurological disorders. However, cues that orchestrate the maintenance versus differentiation of human MGE progenitors, and ways for large-scale expansion of these cells have not been investigated. Here, we report that WNT/CTNNB1 signaling plays an essential role in maintaining MGE-like cells derived from hPSCs. Ablation of CTNNB1 in MGE cells led to precocious cell-cycle exit and advanced neuronal differentiation. Activation of WNT signaling through genetic or chemical approach was sufficient to maintain MGE cells in an expandable manner with authentic neuronal differentiation potencies through activation of endogenous NOTCH signaling. Our findings reveal that WNT/NOTCH signaling cascade is a key player in governing the maintenance versus terminal differentiation of MGE progenitors in humans. Large-scale expansion of functional MGE progenitors for cell therapies can therefore be achieved by modifying WNT/NOTCH pathway. WNT/CTNNB1 signaling is robustly activated in specified human MGE progenitors Ablation of CTNNB1 in human MGE cells leads to advanced neuronal differentiation Activation of WNT signaling maintains MGE progenitors in a proliferative state WNT/CTNNB1 signaling maintains MGE progenitors via activation of NOTCH signaling
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Affiliation(s)
- Lin Ma
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yiran Wang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yi Hui
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Yanhua Du
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Zhenyu Chen
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Hexi Feng
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Shuwei Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Nan Li
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Jianren Song
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China
| | - Yujiang Fang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Xiangjie Xu
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Lei Shi
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Bowen Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Jiayi Cheng
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Shanshan Zhou
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Ling Liu
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China
| | - Xiaoqing Zhang
- Brain and Spinal Cord Innovative Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China; Key Laboratory of Reconstruction and Regeneration of Spine and Spinal Cord Injury, Ministry of Education, Shanghai 200065, China; Key Laboratory of Neuroregeneration of Shanghai Universities, Tongji University School of Medicine, 1239 Siping Road, Room 508, Shanghai 200092, China; Tsingtao Advanced Research Institute, Tongji University, Shanghai 200092, China; Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai 200120, China; Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China.
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10
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Eachus H, Bright C, Cunliffe VT, Placzek M, Wood JD, Watt PJ. Disrupted-in-Schizophrenia-1 is essential for normal hypothalamic-pituitary-interrenal (HPI) axis function. Hum Mol Genet 2017; 26:1992-2005. [PMID: 28334933 PMCID: PMC5437527 DOI: 10.1093/hmg/ddx076] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/23/2017] [Indexed: 02/01/2023] Open
Abstract
Psychiatric disorders arise due to an interplay of genetic and environmental factors, including stress. Studies in rodents have shown that mutants for Disrupted-In-Schizophrenia-1 (DISC1), a well-accepted genetic risk factor for mental illness, display abnormal behaviours in response to stress, but the mechanisms through which DISC1 affects stress responses remain poorly understood. Using two lines of zebrafish homozygous mutant for disc1, we investigated behaviour and functioning of the hypothalamic-pituitary-interrenal (HPI) axis, the fish equivalent of the hypothalamic-pituitary-adrenal (HPA) axis. Here, we show that the role of DISC1 in stress responses is evolutionarily conserved and that DISC1 is essential for normal functioning of the HPI axis. Adult zebrafish homozygous mutant for disc1 show aberrant behavioural responses to stress. Our studies reveal that in the embryo, disc1 is expressed in neural progenitor cells of the hypothalamus, a conserved region of the vertebrate brain that centrally controls responses to environmental stressors. In disc1 mutant embryos, proliferating rx3+ hypothalamic progenitors are not maintained normally and neuronal differentiation is compromised: rx3-derived ff1b+ neurons, implicated in anxiety-related behaviours, and corticotrophin releasing hormone (crh) neurons, key regulators of the stress axis, develop abnormally, and rx3-derived pomc+ neurons are disorganised. Abnormal hypothalamic development is associated with dysfunctional behavioural and neuroendocrine stress responses. In contrast to wild type siblings, disc1 mutant larvae show altered crh levels, fail to upregulate cortisol levels when under stress and do not modulate shoal cohesion, indicative of abnormal social behaviour. These data indicate that disc1 is essential for normal development of the hypothalamus and for the correct functioning of the HPA/HPI axis.
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Affiliation(s)
- Helen Eachus
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.,The Bateson Centre, Department of Biomedical Science, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Charlotte Bright
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Vincent T Cunliffe
- The Bateson Centre, Department of Biomedical Science, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Marysia Placzek
- The Bateson Centre, Department of Biomedical Science, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Jonathan D Wood
- The Bateson Centre, Department of Biomedical Science, Firth Court, Western Bank, Sheffield S10 2TN, UK.,Sheffield Institute for Translational Neuroscience, Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Penelope J Watt
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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11
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Xie Y, Dorsky RI. Development of the hypothalamus: conservation, modification and innovation. Development 2017; 144:1588-1599. [PMID: 28465334 DOI: 10.1242/dev.139055] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hypothalamus, which regulates fundamental aspects of physiological homeostasis and behavior, is a brain region that exhibits highly conserved anatomy across vertebrate species. Its development involves conserved basic mechanisms of induction and patterning, combined with a more plastic process of neuronal fate specification, to produce brain circuits that mediate physiology and behavior according to the needs of each species. Here, we review the factors involved in the induction, patterning and neuronal differentiation of the hypothalamus, highlighting recent evidence that illustrates how changes in Wnt/β-catenin signaling during development may lead to species-specific form and function of this important brain structure.
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Affiliation(s)
- Yuanyuan Xie
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
| | - Richard I Dorsky
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
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12
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Xie Y, Kaufmann D, Moulton MJ, Panahi S, Gaynes JA, Watters HN, Zhou D, Xue HH, Fung CM, Levine EM, Letsou A, Brennan KC, Dorsky RI. Lef1-dependent hypothalamic neurogenesis inhibits anxiety. PLoS Biol 2017; 15:e2002257. [PMID: 28837622 PMCID: PMC5570277 DOI: 10.1371/journal.pbio.2002257] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 07/21/2017] [Indexed: 11/19/2022] Open
Abstract
While innate behaviors are conserved throughout the animal kingdom, it is unknown whether common signaling pathways regulate the development of neuronal populations mediating these behaviors in diverse organisms. Here, we demonstrate that the Wnt/ß-catenin effector Lef1 is required for the differentiation of anxiolytic hypothalamic neurons in zebrafish and mice, although the identity of Lef1-dependent genes and neurons differ between these 2 species. We further show that zebrafish and Drosophila have common Lef1-dependent gene expression in their respective neuroendocrine organs, consistent with a conserved pathway that has diverged in the mouse. Finally, orthologs of Lef1-dependent genes from both zebrafish and mouse show highly correlated hypothalamic expression in marmosets and humans, suggesting co-regulation of 2 parallel anxiolytic pathways in primates. These findings demonstrate that during evolution, a transcription factor can act through multiple mechanisms to generate a common behavioral output, and that Lef1 regulates circuit development that is fundamentally important for mediating anxiety in a wide variety of animal species.
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Affiliation(s)
- Yuanyuan Xie
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Dan Kaufmann
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Matthew J. Moulton
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - Samin Panahi
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - John A. Gaynes
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Harrison N. Watters
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Dingxi Zhou
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
- School of Life Sciences, Peking University, Beijing, China
| | - Hai-Hui Xue
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Camille M. Fung
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Anthea Letsou
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, United States of America
| | - K. C. Brennan
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Richard I. Dorsky
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
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13
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Anand SK, Mondal AC. Cellular and molecular attributes of neural stem cell niches in adult zebrafish brain. Dev Neurobiol 2017; 77:1188-1205. [PMID: 28589616 DOI: 10.1002/dneu.22508] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/05/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022]
Abstract
Adult neurogenesis is a complex, presumably conserved phenomenon in vertebrates with a broad range of variations regarding neural progenitor/stem cell niches, cellular composition of these niches, migratory patterns of progenitors and so forth among different species. Current understanding of the reasons underlying the inter-species differences in adult neurogenic potential, the identification and characterization of various neural progenitors, characterization of the permissive environment of neural stem cell niches and other important aspects of adult neurogenesis is insufficient. In the last decade, zebrafish has emerged as a very useful model for addressing these questions. In this review, we have discussed the present knowledge regarding the neural stem cell niches in adult zebrafish brain as well as their cellular and molecular attributes. We have also highlighted their similarities and differences with other vertebrate species. In the end, we shed light on some of the known intrinsic and extrinsic factors that are assumed to regulate the neurogenic process in adult zebrafish brain. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1188-1205, 2017.
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Affiliation(s)
- Surendra Kumar Anand
- Cellular and Molecular Neurobiology Lab, School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India, 110067
| | - Amal Chandra Mondal
- Cellular and Molecular Neurobiology Lab, School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India, 110067
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14
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Gao Y, Sun T. Molecular regulation of hypothalamic development and physiological functions. Mol Neurobiol 2016; 53:4275-85. [PMID: 26223804 PMCID: PMC4733441 DOI: 10.1007/s12035-015-9367-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 07/17/2015] [Indexed: 01/08/2023]
Abstract
The hypothalamus is composed of many heterogeneous nuclei that control distinct physiological functions. Investigating molecular mechanisms that regulate the specification of these nuclei and specific neuronal subtypes, and their contribution to diverse hypothalamic functions, is an exciting research focus. Here, we begin by summarizing the hypothalamic functions of feeding regulation, sleep-wake cycles, stress responses, and circadian rhythm, and describing their anatomical bases. Next, we review the molecular regulation of formation of hypothalamic territories, specification of nuclei and subnuclei, and generation of specific neurons. Finally, we highlight physiological and behavioral consequences of altered hypothalamic development. Identifying molecules that regulate hypothalamic development and function will increase our understanding of hypothalamus-related disorders, such as obesity and diabetes, and aid in the development of therapies aimed specifically at their etiologies.
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Affiliation(s)
- Yanxia Gao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Tao Sun
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, Box 60, New York, NY, 10065, USA.
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15
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Muthu V, Eachus H, Ellis P, Brown S, Placzek M. Rx3 and Shh direct anisotropic growth and specification in the zebrafish tuberal/anterior hypothalamus. Development 2016; 143:2651-63. [PMID: 27317806 PMCID: PMC4958342 DOI: 10.1242/dev.138305] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/03/2016] [Indexed: 12/11/2022]
Abstract
In the developing brain, growth and differentiation are intimately linked. Here, we show that in the zebrafish embryo, the homeodomain transcription factor Rx3 coordinates these processes to build the tuberal/anterior hypothalamus. Analysis of rx3 chk mutant/rx3 morphant fish and EdU pulse-chase studies reveal that rx3 is required to select tuberal/anterior hypothalamic progenitors and to orchestrate their anisotropic growth. In the absence of Rx3 function, progenitors accumulate in the third ventricular wall, die or are inappropriately specified, the shh(+) anterior recess does not form, and its resident pomc(+), ff1b(+) and otpb(+) Th1(+) cells fail to differentiate. Manipulation of Shh signalling shows that Shh coordinates progenitor cell selection and behaviour by acting as an on-off switch for rx3 Together, our studies show that Shh and Rx3 govern formation of a distinct progenitor domain that elaborates patterning through its anisotropic growth and differentiation.
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Affiliation(s)
- Victor Muthu
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Helen Eachus
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Pam Ellis
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Sarah Brown
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Marysia Placzek
- The Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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16
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Abstract
The neuroendocrine hypothalamus is composed of the tuberal and anterodorsal hypothalamus, together with the median eminence/neurohypophysis. It centrally governs wide-ranging physiological processes, including homeostasis of energy balance, circadian rhythms and stress responses, as well as growth and reproductive behaviours. Homeostasis is maintained by integrating sensory inputs and effecting responses via autonomic, endocrine and behavioural outputs, over diverse time-scales and throughout the lifecourse of an individual. Here, we summarize studies that begin to reveal how different territories and cell types within the neuroendocrine hypothalamus are assembled in an integrated manner to enable function, thus supporting the organism's ability to survive and thrive. We discuss how signaling pathways and transcription factors dictate the appearance and regionalization of the hypothalamic primordium, the maintenance of progenitor cells, and their specification and differentiation into neurons. We comment on recent studies that harness such programmes for the directed differentiation of human ES/iPS cells. We summarize how developmental plasticity is maintained even into adulthood and how integration between the hypothalamus and peripheral body is established in the median eminence and neurohypophysis. Analysis of model organisms, including mouse, chick and zebrafish, provides a picture of how complex, yet elegantly coordinated, developmental programmes build glial and neuronal cells around the third ventricle of the brain. Such conserved processes enable the hypothalamus to mediate its function as a central integrating and response-control mediator for the homeostatic processes that are critical to life. Early indications suggest that deregulation of these events may underlie multifaceted pathological conditions and dysfunctional physiology in humans, such as obesity.
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Affiliation(s)
- Sarah Burbridge
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Iain Stewart
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Marysia Placzek
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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17
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Helfer G, Tups A. Hypothalamic Wnt Signalling and its Role in Energy Balance Regulation. J Neuroendocrinol 2016; 28:12368. [PMID: 26802435 PMCID: PMC4797366 DOI: 10.1111/jne.12368] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 12/22/2022]
Abstract
Wnt signalling and its downstream effectors are well known for their roles in embryogenesis and tumourigenesis, including the regulation of cell proliferation, survival and differentiation. In the nervous system, Wnt signalling has been described mainly during embryonic development, although accumulating evidence suggests that it also plays a major role in adult brain morphogenesis and function. Studies have predominantly concentrated on memory formation in the hippocampus, although recent data indicate that Wnt signalling is also critical for neuroendocrine control of the developed hypothalamus, a brain centre that is key in energy balance regulation and whose dysfunction is implicated in metabolic disorders such as type 2 diabetes and obesity. Based on scattered findings that report the presence of Wnt molecules in the tanycytes and ependymal cells lining the third ventricle and arcuate nucleus neurones of the hypothalamus, their potential importance in key regions of food intake and body weight regulation has been investigated in recent studies. The present review brings together current knowledge on Wnt signalling in the hypothalamus of adult animals and discusses the evidence suggesting a key role for members of the Wnt signalling family in glucose and energy balance regulation in the hypothalamus in diet-induced and genetically obese (leptin deficient) mice. Aspects of Wnt signalling in seasonal (photoperiod sensitive) rodents are also highlighted, given the recent evidence indicating that the Wnt pathway in the hypothalamus is not only regulated by diet and leptin, but also by photoperiod in seasonal animals, which is connected to natural adaptive changes in food intake and body weight. Thus, Wnt signalling appears to be critical as a modulator for normal functioning of the physiological state in the healthy adult brain, and is also crucial for normal glucose and energy homeostasis where its dysregulation can lead to a range of metabolic disorders.
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Affiliation(s)
- G. Helfer
- Rowett Institute of Nutrition and HealthUniversity of AberdeenBucksburnAberdeenUK
| | - A. Tups
- Centre for Neuroendocrinology and Brain Health Research CentreDepartment of PhysiologySchool of Medical SciencesUniversity of OtagoDunedinNew Zealand
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18
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Gaston-Massuet C, McCabe MJ, Scagliotti V, Young RM, Carreno G, Gregory LC, Jayakody SA, Pozzi S, Gualtieri A, Basu B, Koniordou M, Wu CI, Bancalari RE, Rahikkala E, Veijola R, Lopponen T, Graziola F, Turton J, Signore M, Mousavy Gharavy SN, Charolidi N, Sokol SY, Andoniadou CL, Wilson SW, Merrill BJ, Dattani MT, Martinez-Barbera JP. Transcription factor 7-like 1 is involved in hypothalamo-pituitary axis development in mice and humans. Proc Natl Acad Sci U S A 2016; 113:E548-57. [PMID: 26764381 PMCID: PMC4747739 DOI: 10.1073/pnas.1503346113] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aberrant embryonic development of the hypothalamus and/or pituitary gland in humans results in congenital hypopituitarism (CH). Transcription factor 7-like 1 (TCF7L1), an important regulator of the WNT/β-catenin signaling pathway, is expressed in the developing forebrain and pituitary gland, but its role during hypothalamo-pituitary (HP) axis formation or involvement in human CH remains elusive. Using a conditional genetic approach in the mouse, we first demonstrate that TCF7L1 is required in the prospective hypothalamus to maintain normal expression of the hypothalamic signals involved in the induction and subsequent expansion of Rathke's pouch progenitors. Next, we reveal that the function of TCF7L1 during HP axis development depends exclusively on the repressing activity of TCF7L1 and does not require its interaction with β-catenin. Finally, we report the identification of two independent missense variants in human TCF7L1, p.R92P and p.R400Q, in a cohort of patients with forebrain and/or pituitary defects. We demonstrate that these variants exhibit reduced repressing activity in vitro and in vivo relative to wild-type TCF7L1. Together, our data provide support for a conserved molecular function of TCF7L1 as a transcriptional repressor during HP axis development in mammals and identify variants in this transcription factor that are likely to contribute to the etiology of CH.
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Affiliation(s)
- Carles Gaston-Massuet
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Mark J McCabe
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Valeria Scagliotti
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Rodrigo M Young
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Gabriela Carreno
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Louise C Gregory
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Sujatha A Jayakody
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Sara Pozzi
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Angelica Gualtieri
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Basudha Basu
- Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029
| | - Markela Koniordou
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Chun-I Wu
- Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois, IL 60607
| | - Rodrigo E Bancalari
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Elisa Rahikkala
- Research Unit for Pediatrics, Dermatology, Clinical Genetics, Obstetrics and Gynecology (PEDEGO) and Medical Research Center (MRC) Oulu, University of Oulu, FIN-90029, Oulu, Finland; Department of Clinical Genetics, Oulu University Hospital, FIN-90029, Oulu, Finland
| | - Riitta Veijola
- Department of Pediatrics, PEDEGO and MRC Oulu, Oulu University Hospital, University of Oulu, FIN-90014, Oulu, Finland
| | - Tuija Lopponen
- Department of Child Neurology, Kuopio University Hospital, FIN 70029, Kuopio, Finland
| | - Federica Graziola
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - James Turton
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Massimo Signore
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Seyedeh Neda Mousavy Gharavy
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Nicoletta Charolidi
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Sergei Y Sokol
- Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029
| | - Cynthia Lilian Andoniadou
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Bradley J Merrill
- Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois, IL 60607
| | - Mehul T Dattani
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Juan Pedro Martinez-Barbera
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom;
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19
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Understanding multicellular function and disease with human tissue-specific networks. Nat Genet 2015; 47:569-76. [PMID: 25915600 PMCID: PMC4828725 DOI: 10.1038/ng.3259] [Citation(s) in RCA: 543] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/06/2015] [Indexed: 12/17/2022]
Abstract
Tissue and cell-type identity lie at the core of human physiology and disease. Understanding the genetic underpinnings of complex tissues and individual cell lineages is crucial for developing improved diagnostics and therapeutics. We present genome-wide functional interaction networks for 144 human tissues and cell types developed using a data-driven Bayesian methodology that integrates thousands of diverse experiments spanning tissue and disease states. Tissue-specific networks predict lineage-specific responses to perturbation, reveal genes’ changing functional roles across tissues, and illuminate disease-disease relationships. We introduce NetWAS, which combines genes with nominally significant GWAS p-values and tissue-specific networks to identify disease-gene associations more accurately than GWAS alone. Our webserver, GIANT, provides an interface to human tissue networks through multi-gene queries, network visualization, analysis tools including NetWAS, and downloadable networks. GIANT enables systematic exploration of the landscape of interacting genes that shape specialized cellular functions across more than one hundred human tissues and cell types.
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20
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Bedont JL, Newman EA, Blackshaw S. Patterning, specification, and differentiation in the developing hypothalamus. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:445-68. [PMID: 25820448 DOI: 10.1002/wdev.187] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 12/21/2022]
Abstract
Owing to its complex structure and highly diverse cell populations, the study of hypothalamic development has historically lagged behind that of other brain regions. However, in recent years, a greatly expanded understanding of hypothalamic gene expression during development has opened up new avenues of investigation. In this review, we synthesize existing work to present a holistic picture of hypothalamic development from early induction and patterning through nuclear specification and differentiation, with a particular emphasis on determination of cell fate. We will also touch on special topics in the field including the prosomere model, adult neurogenesis, and integration of migratory cells originating outside the hypothalamic neuroepithelium, and how these topics relate to our broader theme.
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Affiliation(s)
- Joseph L Bedont
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elizabeth A Newman
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Seth Blackshaw
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,High-Throughput Biology Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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21
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Fortes MR, HMS Suhaimi A, R. Porto-Neto L, M. McWilliam S, Flatscher-Bader T, S. Moore S, J. D׳Occhio M, T. Meira C, G. Thomas M, M. Snelling W, Reverter A, A. Lehnert S. Post-partum anoestrus in tropical beef cattle: A systems approach combining gene expression and genome-wide association results. Livest Sci 2014. [DOI: 10.1016/j.livsci.2014.06.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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22
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Sousa-Ferreira L, de Almeida LP, Cavadas C. Role of hypothalamic neurogenesis in feeding regulation. Trends Endocrinol Metab 2014; 25:80-8. [PMID: 24231724 DOI: 10.1016/j.tem.2013.10.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 01/10/2023]
Abstract
The recently described generation of new neurons in the adult hypothalamus, the center for energy regulation, suggests that hypothalamic neurogenesis is a crucial part of the mechanisms that regulate food intake. Accordingly, neurogenesis in both the adult and embryonic hypothalamus is affected by nutritional cues and metabolic disorders such as obesity, with consequent effects on energy-balance. This review critically discusses recent findings on the contribution of adult hypothalamic neurogenesis to feeding regulation, the impact of energy-balance disorders on adult hypothalamic neurogenesis, and the influence of embryonic hypothalamic neurogenesis upon feeding regulation in the adult. Understanding how hypothalamic neurogenesis contributes to food intake control will change the paradigm on how we perceive energy-balance regulation.
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Affiliation(s)
- Lígia Sousa-Ferreira
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-517 Coimbra, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Cláudia Cavadas
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, 3004-517 Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
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23
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Kizil C, Iltzsche A, Kaslin J, Brand M. Micromanipulation of gene expression in the adult zebrafish brain using cerebroventricular microinjection of morpholino oligonucleotides. J Vis Exp 2013:e50415. [PMID: 23728426 PMCID: PMC3718288 DOI: 10.3791/50415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Manipulation of gene expression in tissues is required to perform functional studies. In this paper, we demonstrate the cerebroventricular microinjection (CVMI) technique as a means to modulate gene expression in the adult zebrafish brain. By using CVMI, substances can be administered into the cerebroventricular fluid and be thoroughly distributed along the rostrocaudal axis of the brain. We particularly focus on the use of antisense morpholino oligonucleotides, which are potent tools for knocking down gene expression in vivo. In our method, when applied, morpholino molecules are taken up by the cells lining the ventricular surface. These cells include the radial glial cells, which act as neurogenic progenitors. Therefore, knocking down gene expression in the radial glial cells is of utmost importance to analyze the widespread neurogenesis response in zebrafish, and also would provide insight into how vertebrates could sustain adult neurogenesis response. Such an understanding would also help the efforts for clinical applications in human neurodegenerative disorders and central nervous system regeneration. Thus, we present the cerebroventricular microinjection method as a quick and efficient way to alter gene expression and neurogenesis response in the adult zebrafish forebrain. We also provide troubleshooting tips and other useful information on how to carry out the CVMI procedure.
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Affiliation(s)
- Caghan Kizil
- DFG-Center for Regenerative Therapies Dresden, Cluster of Excellence (CRTD) and Biotechnology Center (BIOTEC) of the Technische Universität Dresden.
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24
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Bosco A, Bureau C, Affaticati P, Gaspar P, Bally-Cuif L, Lillesaar C. Development of hypothalamic serotoninergic neurons requires Fgf signalling via the ETS-domain transcription factor Etv5b. Development 2013; 140:372-84. [PMID: 23250211 DOI: 10.1242/dev.089094] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Serotonin is a monoamine neurotransmitter that is involved in numerous physiological functions and its dysregulation is implicated in various psychiatric diseases. In all non-placental vertebrates, serotoninergic (5-HT) neurons are present in several regions of the brain, including the hypothalamus. In placental mammals, however, 5-HT neurons are located in the raphe nuclei only. In all species, though, 5-HT neurons constitute a functionally and molecularly heterogeneous population. How the non-raphe 5-HT populations are developmentally encoded is unknown. Using the zebrafish model we show that, in contrast to the raphe populations, hypothalamic 5-HT neurons are generated independently of the ETS-domain transcription factor Pet1 (Fev). By applying a combination of pharmacological tools and gene knockdown and/or overexpression experiments, we demonstrate that Fgf signalling acts via another ETS-domain transcription factor, Etv5b (Erm), to induce hypothalamic 5-HT neurons. We provide evidence that Etv5b exerts its effects by regulating cell cycle parameters in 5-HT progenitors. Our results highlight a novel role for Etv5b in neuronal development and provide support for the existence of a developmental heterogeneity among 5-HT neurons in their requirement for ETS-domain transcription factors.
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Affiliation(s)
- Adriana Bosco
- Zebrafish Neurogenetics Group, Laboratory of Neurobiology and Development, CNRS UPR3294, Institute of Neurobiology Albert Fessard, 1 Avenue de Terrasse, 91198 Gif-sur-Yvette, France
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Wang X, Kopinke D, Lin J, McPherson AD, Duncan RN, Otsuna H, Moro E, Hoshijima K, Grunwald DJ, Argenton F, Chien CB, Murtaugh LC, Dorsky RI. Wnt signaling regulates postembryonic hypothalamic progenitor differentiation. Dev Cell 2013; 23:624-36. [PMID: 22975330 DOI: 10.1016/j.devcel.2012.07.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 05/15/2012] [Accepted: 07/17/2012] [Indexed: 12/21/2022]
Abstract
Previous studies have raised the possibility that Wnt signaling may regulate both neural progenitor maintenance and neuronal differentiation within a single population. Here we investigate the role of Wnt/β-catenin activity in the zebrafish hypothalamus and find that the pathway is first required for the proliferation of unspecified hypothalamic progenitors in the embryo. At later stages, including adulthood, sequential activation and inhibition of Wnt activity is required for the differentiation of neural progenitors and negatively regulates radial glia differentiation. The presence of Wnt activity is conserved in hypothalamic progenitors of the adult mouse, where it plays a conserved role in inhibiting the differentiation of radial glia. This study establishes the vertebrate hypothalamus as a model for Wnt-regulated postembryonic neural progenitor differentiation and defines specific roles for Wnt signaling in neurogenesis.
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Affiliation(s)
- Xu Wang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84112, USA
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Gaspar P, Lillesaar C. Probing the diversity of serotonin neurons. Philos Trans R Soc Lond B Biol Sci 2012; 367:2382-94. [PMID: 22826339 DOI: 10.1098/rstb.2011.0378] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The serotonin (5-HT) system is generally considered as a single modulatory system, with broad and diffuse projections. However, accumulating evidence points to the existence of distinct cell groups in the raphe. Here, we review prior evidence for raphe cell heterogeneity, considering different properties of 5-HT neurons, from metabolism to anatomy, and neurochemistry to physiology. We then summarize more recent data in mice and zebrafish that support a genetic diversity of 5-HT neurons, based on differential transcription factor requirements for the acquisition of the 5-HT identity. In both species, PET1 plays a major role in the acquisition and maintenance of 5-HT identity in the hindbrain, although some 5-HT neurons do not require PET1 for their differentiation, indicating the existence of several transcriptional routes to become serotoninergic. In mice, both PET1-dependent and -independent 5-HT neurons are located in the raphe, but have distinct anatomical features, such as the morphology of axon terminals and projection patterns. In zebrafish, all raphe neurons express pet1, but Pet1-independent 5-HT cell groups are present in the forebrain. Overall, these observations support the view that there are a number of distinct 5-HT subsystems, including within the raphe nuclei, with unique genetic programming and functions.
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Affiliation(s)
- Patricia Gaspar
- UMR-S 839, INSERM, , 17, rue du Fer à Moulin, 75005 Paris, France.
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Shimizu N, Kawakami K, Ishitani T. Visualization and exploration of Tcf/Lef function using a highly responsive Wnt/β-catenin signaling-reporter transgenic zebrafish. Dev Biol 2012; 370:71-85. [PMID: 22842099 DOI: 10.1016/j.ydbio.2012.07.016] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 07/03/2012] [Accepted: 07/10/2012] [Indexed: 01/09/2023]
Abstract
Evolutionarily conserved Tcf/Lef transcription factors (Lef1, Tcf7, Tcf7l1, and Tcf7l2) mediate gene expression regulated by Wnt/β-catenin signaling, which has multiple roles in early embryogenesis, organogenesis, adult tissue homeostasis, and tissue regeneration. However, the spatiotemporal dynamics of Tcf/Lef activity during these events remain poorly understood. We generated stable transgenic zebrafish lines carrying a new Wnt/β-catenin signaling reporter, Tcf/Lef-miniP:dGFP. The reporter revealed the transcriptional activities of four Tcf/Lef members controlled by Wnt/β-catenin signaling, which were expressed in known Wnt/β-catenin signaling-active sites during embryogenesis, organ development and growth, and tissue regeneration. We used the transgenic lines to demonstrate the contribution of Tcf/Lef-mediated Wnt/β-catenin signaling to the development of the anterior lateral line, dorsal and secondary posterior lateral lines, and gill filaments. Thus, these reporter lines are highly useful tools for studying Tcf/Lef-mediated Wnt/β-catenin signaling-dependent processes.
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Affiliation(s)
- Nobuyuki Shimizu
- Division of Cell Regulation Systems, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Chapouton P, Webb KJ, Stigloher C, Alunni A, Adolf B, Hesl B, Topp S, Kremmer E, Bally-Cuif L. Expression of hairy/enhancer of split genes in neural progenitors and neurogenesis domains of the adult zebrafish brain. J Comp Neurol 2012; 519:1748-69. [PMID: 21452233 DOI: 10.1002/cne.22599] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
All subdivisions of the adult zebrafish brain maintain niches of constitutive neurogenesis, sustained by quiescent and multipotent progenitor populations. In the telencephalon, the latter potential neural stem cells take the shape of radial glia aligned along the ventricle and are controlled by Notch signalling. With the aim of identifying new markers of this cell type and of comparing the effectors of embryonic and adult neurogenesis, we focused on the family of hairy/enhancer of split [E(spl)] genes. We report the expression of seven hairy/E(spl) (her) genes and the new helt gene in three neurogenic areas of the adult zebrafish brain (telencephalon, hypothalamus, and midbrain) in relation to radial glia, proliferation, and neurogenesis. We show that the expression of most her genes in the adult brain characterizes quiescent radial glia, whereas only few are expressed in progenitor domains engaged in active proliferation or neurogenesis. The low proliferation status of most her-positive progenitors contrasts with the embryonic nervous system, in which her genes are expressed in actively dividing progenitors. Likewise, we demonstrate largely overlapping expression domains of a set of her genes in the adult brain, which is in striking contrast to their distinct embryonic expression profiles. Overall, our data provide a consolidated map of her expression, quiescent glia, proliferation, and neurogenesis in these various subdivisions of the adult brain and suggest distinct regulation and function of Her factors in the embryonic and adult contexts.
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Affiliation(s)
- Prisca Chapouton
- Zebrafish Neurogenetics Department, Helmholtz Zentrum München, German Research Center for Environmental Health, D-85764 Neuherberg, Germany.
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Mahmoudi T, Boj SF, Hatzis P, Li VSW, Taouatas N, Vries RGJ, Teunissen H, Begthel H, Korving J, Mohammed S, Heck AJR, Clevers H. The leukemia-associated Mllt10/Af10-Dot1l are Tcf4/β-catenin coactivators essential for intestinal homeostasis. PLoS Biol 2010; 8:e1000539. [PMID: 21103407 PMCID: PMC2982801 DOI: 10.1371/journal.pbio.1000539] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 10/01/2010] [Indexed: 01/07/2023] Open
Abstract
Wnt signaling maintains the undifferentiated state of intestinal crypt progenitor cells by inducing the formation of nuclear TCF4/β-catenin complexes. In colorectal cancer, activating mutations in Wnt pathway components cause inappropriate activation of TCF4/β-catenin-driven transcription. Despite the passage of a decade after the discovery of TCF4 and β-catenin as the molecular effectors of the Wnt signal, few transcriptional activators essential and unique to the regulation of this transcription program have been found. Using proteomics, we identified the leukemia-associated Mllt10/Af10 and the methyltransferase Dot1l as Tcf4/β-catenin interactors in mouse small intestinal crypts. Mllt10/Af10-Dot1l, essential for transcription elongation, are recruited to Wnt target genes in a β-catenin-dependent manner, resulting in H3K79 methylation over their coding regions in vivo in proliferative crypts of mouse small intestine in colorectal cancer and Wnt-inducible HEK293T cells. Depletion of MLLT10/AF10 in colorectal cancer and Wnt-inducible HEK293T cells followed by expression array analysis identifies MLLT10/AF10 and DOT1L as essential activators to a large extent dedicated to Wnt target gene regulation. In contrast, previously published β-catenin coactivators p300 and BRG1 displayed a more pleiotropic target gene expression profile controlling Wnt and other pathways. tcf4, mllt10/af10, and dot1l are co-expressed in Wnt-driven tissues in zebrafish and essential for Wnt-reporter activity. Intestinal differentiation defects in apc-mutant zebrafish can be rescued by depletion of Mllt10 and Dot1l, establishing these genes as activators downstream of Apc in Wnt target gene activation in vivo. Morpholino-depletion of mllt10/af10-dot1l in zebrafish results in defects in intestinal homeostasis and a significant reduction in the in vivo expression of direct Wnt target genes and in the number of proliferative intestinal epithelial cells. We conclude that Mllt10/Af10-Dot1l are essential, largely dedicated activators of Wnt-dependent transcription, critical for maintenance of intestinal proliferation and homeostasis. The methyltransferase DOT1L may present an attractive candidate for drug targeting in colorectal cancer.
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Affiliation(s)
- Tokameh Mahmoudi
- Hubrecht Institute and University Medical Centre Utrecht, Utrecht, The Netherlands.
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