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Altbürger C, Rath M, Armbruster D, Driever W. Neurog1 and Olig2 integrate patterning and neurogenesis signals in development of zebrafish dopaminergic and glutamatergic dual transmitter neurons. Dev Biol 2024; 505:85-98. [PMID: 37944224 DOI: 10.1016/j.ydbio.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/02/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
Dopaminergic neurons develop in distinct neural domains by integrating local patterning and neurogenesis signals. While the proneural proteins Neurog1 and Olig2 have been previously linked to development of dopaminergic neurons, their dependence on local prepatterning and specific contributions to dopaminergic neurogenesis are not well understood. Here, we show that both transcription factors are differentially required for the development of defined dopaminergic glutamatergic subpopulations in the zebrafish posterior tuberculum, which are homologous to A11 dopaminergic neurons in mammals. Both Olig2 and Neurog1 are expressed in otpa expressing progenitor cells and appear to act upstream of Otpa during dopaminergic neurogenesis. Our epistasis analysis confirmed that Neurog1 acts downstream of Notch signaling, while Olig2 acts downstream of Shh, but upstream and/or in parallel to Notch signaling during neurogenesis of A11-type dopaminergic clusters. Furthermore, we identified Olig2 to be an upstream regulator of neurog1 in dopaminergic neurogenesis. This regulation occurs through Olig2-dependent repression of the proneural repressor and Notch target gene her2. Our study reveals how Neurog1 and Olig2 integrate local patterning signals, including Shh, with Notch neurogenic selection signaling, to specify the progenitor population and initiate neurogenesis and differentiation of A11-type dopaminergic neurons.
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Affiliation(s)
- Christian Altbürger
- Department of Developmental Biology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Meta Rath
- Department of Developmental Biology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, Germany
| | - Daniel Armbruster
- Department of Developmental Biology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, Germany; MeInBio Research Training Group, University of Freiburg, 79104 Freiburg, Germany
| | - Wolfgang Driever
- Department of Developmental Biology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany.
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2
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Will I, Beckerson WC, de Bekker C. Using machine learning to predict protein-protein interactions between a zombie ant fungus and its carpenter ant host. Sci Rep 2023; 13:13821. [PMID: 37620441 PMCID: PMC10449854 DOI: 10.1038/s41598-023-40764-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023] Open
Abstract
Parasitic fungi produce proteins that modulate virulence, alter host physiology, and trigger host responses. These proteins, classified as a type of "effector," often act via protein-protein interactions (PPIs). The fungal parasite Ophiocordyceps camponoti-floridani (zombie ant fungus) manipulates Camponotus floridanus (carpenter ant) behavior to promote transmission. The most striking aspect of this behavioral change is a summit disease phenotype where infected hosts ascend and attach to an elevated position. Plausibly, interspecific PPIs drive aspects of Ophiocordyceps infection and host manipulation. Machine learning PPI predictions offer high-throughput methods to produce mechanistic hypotheses on how this behavioral manipulation occurs. Using D-SCRIPT to predict host-parasite PPIs, we found ca. 6000 interactions involving 2083 host proteins and 129 parasite proteins, which are encoded by genes upregulated during manipulated behavior. We identified multiple overrepresentations of functional annotations among these proteins. The strongest signals in the host highlighted neuromodulatory G-protein coupled receptors and oxidation-reduction processes. We also detected Camponotus structural and gene-regulatory proteins. In the parasite, we found enrichment of Ophiocordyceps proteases and frequent involvement of novel small secreted proteins with unknown functions. From these results, we provide new hypotheses on potential parasite effectors and host targets underlying zombie ant behavioral manipulation.
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Affiliation(s)
- Ian Will
- Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL, 32816, USA.
| | - William C Beckerson
- Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL, 32816, USA
| | - Charissa de Bekker
- Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL, 32816, USA.
- Department of Biology, Microbiology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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Silva N, Campinho MA. In a zebrafish biomedical model of human Allan-Herndon-Dudley syndrome impaired MTH signaling leads to decreased neural cell diversity. Front Endocrinol (Lausanne) 2023; 14:1157685. [PMID: 37214246 PMCID: PMC10194031 DOI: 10.3389/fendo.2023.1157685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/04/2023] [Indexed: 05/24/2023] Open
Abstract
Background Maternally derived thyroid hormone (T3) is a fundamental factor for vertebrate neurodevelopment. In humans, mutations on the thyroid hormones (TH) exclusive transporter monocarboxylic acid transporter 8 (MCT8) lead to the Allan-Herndon-Dudley syndrome (AHDS). Patients with AHDS present severe underdevelopment of the central nervous system, with profound cognitive and locomotor consequences. Functional impairment of zebrafish T3 exclusive membrane transporter Mct8 phenocopies many symptoms observed in patients with AHDS, thus providing an outstanding animal model to study this human condition. In addition, it was previously shown in the zebrafish mct8 KD model that maternal T3 (MTH) acts as an integrator of different key developmental pathways during zebrafish development. Methods Using a zebrafish Mct8 knockdown model, with consequent inhibition of maternal thyroid hormones (MTH) uptake to the target cells, we analyzed genes modulated by MTH by qPCR in a temporal series from the start of segmentation through hatching. Survival (TUNEL) and proliferation (PH3) of neural progenitor cells (dla, her2) were determined, and the cellular distribution of neural MTH-target genes in the spinal cord during development was characterized. In addition, in-vivo live imaging was performed to access NOTCH overexpression action on cell division in this AHDS model. We determined the developmental time window when MTH is required for appropriate CNS development in the zebrafish; MTH is not involved in neuroectoderm specification but is fundamental in the early stages of neurogenesis by promoting the maintenance of specific neural progenitor populations. MTH signaling is required for developing different neural cell types and maintaining spinal cord cytoarchitecture, and modulation of NOTCH signaling in a non-autonomous cell manner is involved in this process. Discussion The findings show that MTH allows the enrichment of neural progenitor pools, regulating the cell diversity output observed by the end of embryogenesis and that Mct8 impairment restricts CNS development. This work contributes to the understanding of the cellular mechanisms underlying human AHDS.
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Affiliation(s)
- Nádia Silva
- Centre for Marine Sciences of the University of the Algarve, Faro, Portugal
- Algarve Biomedical Center-Research Institute, University of the Algarve, Faro, Portugal
| | - Marco António Campinho
- Centre for Marine Sciences of the University of the Algarve, Faro, Portugal
- Algarve Biomedical Center-Research Institute, University of the Algarve, Faro, Portugal
- Faculty of Medicine and Biomedical Sciences, University of the Algarve, Faro, Portugal
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4
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Identification of the Time Period during Which BMP Signaling Regulates Proliferation of Neural Progenitor Cells in Zebrafish. Int J Mol Sci 2023; 24:ijms24021733. [PMID: 36675251 PMCID: PMC9863262 DOI: 10.3390/ijms24021733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/06/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
Bone morphogenetic protein (BMP) signaling regulates neural induction, neuronal specification, and neuronal differentiation. However, the role of BMP signaling in neural progenitors remains unclear. This is because interruption of BMP signaling before or during neural induction causes severe effects on subsequent neural developmental processes. To examine the role of BMP signaling in the development of neural progenitors in zebrafish, we bypassed the effect of BMP signaling on neural induction and suppressed BMP signaling at different time points during gastrulation using a temporally controlled transgenic line carrying a dominant-negative form of Bmp receptor type 1aa and a chemical inhibitor of BMP signaling, DMH1. Inhibiting BMP signaling from 8 hpf could bypass BMP regulation on neural induction, induce the number of proliferating neural progenitors, and reduce the number of neuronal precursors. Inhibiting BMP signaling upregulates the expression of the Notch downstream gene hairy/E(spl)-related 2 (her2). Inhibiting Notch signaling or knocking down the Her2 function reduced neural progenitor proliferation, whereas inactivating BMP signaling in Notch-Her2 deficient background restored the number of proliferating neural progenitors. These results reveal the time window for the proliferation of neural progenitors during zebrafish development and a fine balance between BMP and Notch signaling in regulating the proliferation of neural progenitor cells.
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Cao J, Li Y, Zeng F, Liu X, Tao T, Qin Z. Propofol Exposure Disturbs the Differentiation of Rodent Neural Stem Cells via an miR-124-3p/Sp1/Cdkn1b Axis. Front Cell Dev Biol 2020; 8:838. [PMID: 32984332 PMCID: PMC7481336 DOI: 10.3389/fcell.2020.00838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 08/05/2020] [Indexed: 11/13/2022] Open
Abstract
Accumulating studies have indicated that propofol may lead to neurotoxicity and its effect on neural stem cells (NSCs) may play pivotal role in propofol-related neurotoxicity. Previously, we found that propofol could promote NSCs proliferation and could regulate several microRNA expressions. However, the underlying mechanism between microRNAs and NSCs development after propofol exposure is still unclear. Our data first observed that rat primary neural stem cells exposed to propofol exhibited a cell cycle arrest status and an inclination to differentiate into GFAP+ or S100β+ cells. This phenomenon was accompanying with a lower miR-124-3p expression and could be reversed via overexpression miR-124-3p in NSCs. Using bioinformatic predictions and luciferase assay we confirmed that Sp1 (Specificity Protein 1) is the target gene of miR-124-3p, indicating that miR-124-3p may regulate NSCs development through Sp1. Further, knockdown of Sp1 rescue the effect of propofol on NSCs differentiation. Finally, we demonstrated that Sp1 could bind cdkn1b promoter region through chromatin immunoprecipitation assay, indicating that Sp1 affect NSC's cell cycle through cdkn1b directly. Overall, our study highlights the miR-124-3p/Sp1/cdkn1b axis to be important in propofol interfering the differentiation of NSCs.
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Affiliation(s)
- Jun Cao
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Anesthesiology, Affiliated Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University, Shenzhen, China
| | - Yan Li
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Anesthesiology, Cangzhou Central Hospital, Cangzhou, China
| | - Fanning Zeng
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaolei Liu
- Department of Anesthesiology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Tao Tao
- Department of Anesthesiology, The Central People's Hospital of Zhanjiang, Zhanjiang, China
| | - Zaisheng Qin
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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Gothié J, Vancamp P, Demeneix B, Remaud S. Thyroid hormone regulation of neural stem cell fate: From development to ageing. Acta Physiol (Oxf) 2020; 228:e13316. [PMID: 31121082 PMCID: PMC9286394 DOI: 10.1111/apha.13316] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/10/2019] [Accepted: 05/17/2019] [Indexed: 12/13/2022]
Abstract
In the vertebrate brain, neural stem cells (NSCs) generate both neuronal and glial cells throughout life. However, their neuro‐ and gliogenic capacity changes as a function of the developmental context. Despite the growing body of evidence on the variety of intrinsic and extrinsic factors regulating NSC physiology, their precise cellular and molecular actions are not fully determined. Our review focuses on thyroid hormone (TH), a vital component for both development and adult brain function that regulates NSC biology at all stages. First, we review comparative data to analyse how TH modulates neuro‐ and gliogenesis during vertebrate brain development. Second, as the mammalian brain is the most studied, we highlight the molecular mechanisms underlying TH action in this context. Lastly, we explore how the interplay between TH signalling and cell metabolism governs both neurodevelopmental and adult neurogenesis. We conclude that, together, TH and cellular metabolism regulate optimal brain formation, maturation and function from early foetal life to adult in vertebrate species.
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Affiliation(s)
- Jean‐David Gothié
- Department of Neurology & Neurosurgery Montreal Neurological Institute & Hospital, McGill University Montreal Quebec Canada
| | - Pieter Vancamp
- CNRS UMR 7221 Muséum National d’Histoire Naturelle Paris France
| | | | - Sylvie Remaud
- CNRS UMR 7221 Muséum National d’Histoire Naturelle Paris France
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Mitochondrial enzyme GLUD2 plays a critical role in glioblastoma progression. EBioMedicine 2018; 37:56-67. [PMID: 30314897 PMCID: PMC6284416 DOI: 10.1016/j.ebiom.2018.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 01/06/2023] Open
Abstract
Background Glioblastoma (GBM) is the most frequent and malignant primary brain tumor in adults and despite the progress in surgical procedures and therapy options, the overall survival remains very poor. Glutamate and α-KG are fundamental elements necessary to support the growth and proliferation of GBM cells. Glutamate oxidative deamination, catalyzed by GLUD2, is the predominant pathway for the production of α-KG. Methods GLUD2 emerged from the RNA-seq analysis of 13 GBM patients, performed in our laboratory and a microarray analysis of 77 high-grade gliomas available on the Geo database. Thereafter, we investigated GLUD2 relevance in cancer cell behavior by GLUD2 overexpression and silencing in two different human GBM cell lines. Finally, we overexpressed GLUD2 in-vivo by using zebrafish embryos and monitored the developing central nervous system. Findings GLUD2 expression was found associated to the histopathological classification, prognosis and survival of GBM patients. Moreover, through in-vitro functional studies, we showed that differences in GLUD2 expression level affected cell proliferation, migration, invasion, colony formation abilities, cell cycle phases, mitochondrial function and ROS production. In support of these findings, we also demonstrated, with in-vivo studies, that GLUD2 overexpression affects glial cell proliferation without affecting neuronal development in zebrafish embryos. Interpretation We concluded that GLUD2 overexpression inhibited GBM cell growth suggesting a novel potential drug target for control of GBM progression. The possibility to enhance GLUD2 activity in GBM could result in a blocked/reduced proliferation of GBM cells without affecting the survival of the surrounding neurons.
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8
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Silva N, Louro B, Trindade M, Power DM, Campinho MA. Transcriptomics reveal an integrative role for maternal thyroid hormones during zebrafish embryogenesis. Sci Rep 2017; 7:16657. [PMID: 29192226 PMCID: PMC5709499 DOI: 10.1038/s41598-017-16951-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 11/20/2017] [Indexed: 02/06/2023] Open
Abstract
Thyroid hormones (THs) are essential for embryonic brain development but the genetic mechanisms involved in the action of maternal THs (MTHs) are still largely unknown. As the basis for understanding the underlying genetic mechanisms of MTHs regulation we used an established zebrafish monocarboxylic acid transporter 8 (MCT8) knock-down model and characterised the transcriptome in 25hpf zebrafish embryos. Subsequent mapping of differentially expressed genes using Reactome pathway analysis together with in situ expression analysis and immunohistochemistry revealed the genetic networks and cells under MTHs regulation during zebrafish embryogenesis. We found 4,343 differentially expressed genes and the Reactome pathway analysis revealed that TH is involved in 1681 of these pathways. MTHs regulated the expression of core developmental pathways, such as NOTCH and WNT in a cell specific context. The cellular distribution of neural MTH-target genes demonstrated their cell specific action on neural stem cells and differentiated neuron classes. Taken together our data show that MTHs have a role in zebrafish neurogenesis and suggest they may be involved in cross talk between key pathways in neural development. Given that the observed MCT8 zebrafish knockdown phenotype resembles the symptoms in human patients with Allan-Herndon-Dudley syndrome our data open a window into understanding the genetics of this human congenital condition.
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Affiliation(s)
- Nadia Silva
- Comparative Endocrinology and Integrative Biology Group, Centre for Marine Sciences (CCMAR), Universidade do Algarve, Faro, Portugal
| | - Bruno Louro
- Comparative Endocrinology and Integrative Biology Group, Centre for Marine Sciences (CCMAR), Universidade do Algarve, Faro, Portugal
| | - Marlene Trindade
- Comparative Endocrinology and Integrative Biology Group, Centre for Marine Sciences (CCMAR), Universidade do Algarve, Faro, Portugal
| | - Deborah M Power
- Comparative Endocrinology and Integrative Biology Group, Centre for Marine Sciences (CCMAR), Universidade do Algarve, Faro, Portugal
| | - Marco A Campinho
- Comparative Endocrinology and Integrative Biology Group, Centre for Marine Sciences (CCMAR), Universidade do Algarve, Faro, Portugal.
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9
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Sullivan JM, Havrda MC, Kettenbach AN, Paolella BR, Zhang Z, Gerber SA, Israel MA. Phosphorylation Regulates Id2 Degradation and Mediates the Proliferation of Neural Precursor Cells. Stem Cells 2016; 34:1321-31. [PMID: 26756672 DOI: 10.1002/stem.2291] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/23/2015] [Accepted: 12/07/2015] [Indexed: 01/07/2023]
Abstract
Inhibitor of DNA binding proteins (Id1-Id4) function to inhibit differentiation and promote proliferation of many different cell types. Among the Id family members, Id2 has been most extensively studied in the central nervous system (CNS). Id2 contributes to cultured neural precursor cell (NPC) proliferation as well as to the proliferation of CNS tumors such as glioblastoma that are likely to arise from NPC-like cells. We identified three phosphorylation sites near the N-terminus of Id2 in NPCs. To interrogate the importance of Id2 phosphorylation, Id2(-/-) NPCs were modified to express wild type (WT) Id2 or an Id2 mutant protein that could not be phosphorylated at the identified sites. We observed that NPCs expressing this mutant lacking phosphorylation near the N-terminus had higher steady-state levels of Id2 when compared to NPCs expressing WT Id2. This elevated level was the result of a longer half-life and reduced proteasome-mediated degradation. Moreover, NPCs expressing constitutively de-phosphorylated Id2 proliferated more rapidly than NPCs expressing WT Id2, a finding consistent with the well-characterized function of Id2 in driving proliferation. Observing that phosphorylation of Id2 modulates the degradation of this important cell-cycle regulator, we sought to identify a phosphatase that would stabilize Id2 enhancing its activity in NPCs and extended our analysis to include human glioblastoma-derived stem cells (GSCs). We found that expression of the phosphatase PP2A altered Id2 levels. Our findings suggest that inhibition of PP2A may be a novel strategy to regulate the proliferation of normal NPCs and malignant GSCs by decreasing Id2 levels. Stem Cells 2016;34:1321-1331.
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Affiliation(s)
- Jaclyn M Sullivan
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Matthew C Havrda
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Pediatrics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Arminja N Kettenbach
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Brenton R Paolella
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Zhonghua Zhang
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Pediatrics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Scott A Gerber
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Mark A Israel
- Pharmacology and Toxicology, Norris Cotton Cancer Center, One Medical Center Drive, Lebanon, NH, 03756.,Department of Pediatrics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Cheng YC, Huang YC, Yeh TH, Shih HY, Lin CY, Lin SJ, Chiu CC, Huang CW, Jiang YJ. Deltex1 is inhibited by the Notch-Hairy/E(Spl) signaling pathway and induces neuronal and glial differentiation. Neural Dev 2015; 10:28. [PMID: 26714454 PMCID: PMC4696291 DOI: 10.1186/s13064-015-0055-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/20/2015] [Indexed: 12/23/2022] Open
Abstract
Background Notch signaling has been conserved throughout evolution and plays a fundamental role in various neural developmental processes and the pathogenesis of several human cancers and genetic disorders. However, how Notch signaling regulates various cellular processes remains unclear. Although Deltex proteins have been identified as cytoplasmic downstream elements of the Notch signaling pathway, few studies have been reported on their physiological role. Results We isolated zebrafish deltex1 (dtx1) and showed that this gene is primarily transcribed in the developing nervous system, and its spatiotemporal expression pattern suggests a role in neural differentiation. The transcription of dtx1 was suppressed by the direct binding of the Notch downstream transcription factors Her2 and Her8a. Overexpressing the complete coding sequence of Dtx1 was necessary for inducing neuronal and glial differentiation. By contrast, disrupting Dtx1 expression by using a Dtx1 construct without the RING finger domain reduced neuronal and glial differentiation. This effect was phenocopied by the knockdown of endogenous Dtx1 expression by using morpholinos, demonstrating the essential function of the RING finger domain and confirming the knockdown specificity. Cell proliferation and apoptosis were unaltered in Dtx1-overexpressed and -deficient zebrafish embryos. Examination of the expression of her2 and her8a in embryos with altered Dtx1 expression showed that Dxt1-induced neuronal differentiation did not require a regulatory effect on the Notch–Hairy/E(Spl) pathway. However, both Dtx1 and Notch activation induced glial differentiation, and Dtx1 and Notch activation negatively inhibited each other in a reciprocal manner, which achieves a proper balance for the expression of Dtx1 and Notch to facilitate glial differentiation. We further confirmed that the Dtx1–Notch–Hairy/E(Spl) cascade was sufficient to induce neuronal and glial differentiation by concomitant injection of an active form of Notch with dtx1, which rescued the neuronogenic and gliogenic defects caused by the activation of Notch signaling. Conclusions Our results demonstrated that Dtx1 is regulated by Notch–Hairy/E(Spl) signaling and is a major factor specifically regulating neural differentiation. Thus, our results provide new insights into the mediation of neural development by the Notch signaling pathway. Electronic supplementary material The online version of this article (doi:10.1186/s13064-015-0055-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi-Chuan Cheng
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Taoyuan, 33383, Taiwan. .,Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan.
| | - Yin-Cheng Huang
- Department of Neurosurgery, Chang Gung Memorial Hospital, Chiayi branch, Chiayi, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tu-Hsueh Yeh
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Section of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Hung-Yu Shih
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Taoyuan, 33383, Taiwan
| | - Ching-Yu Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Taoyuan, 33383, Taiwan
| | - Sheng-Jia Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Taoyuan, 33383, Taiwan
| | - Ching-Chi Chiu
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou Medical Center, Taoyuan, Taiwan
| | - Ching-Wen Huang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Taoyuan, 33383, Taiwan
| | - Yun-Jin Jiang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan
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11
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Gao H, Bu Y, Wu Q, Wang X, Chang N, Lei L, Chen S, Liu D, Zhu X, Hu K, Xiong JW. Mecp2 regulates neural cell differentiation by suppressing the Id1 to Her2 axis in zebrafish. J Cell Sci 2015; 128:2340-50. [DOI: 10.1242/jcs.167874] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/28/2015] [Indexed: 01/20/2023] Open
Abstract
ABSTRACT
Rett syndrome (RTT) is a progressive neurological disorder caused by mutations in the X-linked protein methyl-CpG-binding protein 2 (MeCP2). The endogenous function of MeCP2 during neural differentiation is still unclear. Here, we report that mecp2 is required for brain development in zebrafish. Mecp2 was broadly expressed initially in embryos and enriched later in the brain. Either morpholino knockdown or genetic depletion of mecp2 inhibited neuronal differentiation, whereas its overexpression promoted neuronal differentiation, suggesting an essential role of mecp2 in directing neural precursors into differentiated neurons. Mechanistically, her2 (the zebrafish ortholog of mammalian Hes5) was upregulated in mecp2 morphants in an Id1-dependent manner. Moreover, knockdown of either her2 or id1 fully rescued neuronal differentiation in mecp2 morphants. These results suggest that Mecp2 plays an important role in neural cell development by suppressing the Id1–Her2 axis, and provide new evidence that embryonic neural defects contribute to the later motor and cognitive dysfunctions in RTT.
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Affiliation(s)
- Hai Gao
- Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, China
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Ye Bu
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Qing Wu
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xu Wang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Nannan Chang
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Lei Lei
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Shilin Chen
- Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, China
| | - Dong Liu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Peking University, Beijing, China
| | - Xiaojun Zhu
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Keping Hu
- Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, China
| | - Jing-Wei Xiong
- Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Institute of Molecular Medicine, Peking University, Beijing, China
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