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Abstract
In situ hybridization enables visualization of mRNA localization, and immunohistochemistry enables visualization of protein localization within a tissue or organism. Both techniques have been extensively utilized in zebrafish (Thisse et al., Development 119:1203-1215, 1993; Dutton et al., Development 128:4113-4125, 2001; Gilmour et al., Neuron 34:577-588, 2002; Lyons et al., Curr Biol 15:513-524, 2005) including for visualization of mRNA localization in Schwann cells (Lyons et al., Curr Biol 15:513-524, 2005; Monk et al., Science 325:1402-1405, 2009). For in situ hybridization, here, we outline how to generate RNA probes, conduct whole mount in situ hybridization for larvae, and list RNA probes that label different stages of Schwann cell development in zebrafish. For immunohistochemistry, the protocol we outline can be used to mark Schwann cells of sensory and motor nerves to examine properties such as developmental stage, morphology, proliferation, and apoptosis.
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Chen Q, Yin D, Jia Y, Schiwy S, Legradi J, Yang S, Hollert H. Enhanced uptake of BPA in the presence of nanoplastics can lead to neurotoxic effects in adult zebrafish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 609:1312-1321. [PMID: 28793400 DOI: 10.1016/j.scitotenv.2017.07.144] [Citation(s) in RCA: 264] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/14/2017] [Accepted: 07/16/2017] [Indexed: 04/14/2023]
Abstract
Plastic particles have been proven to be abundant in the aquatic environment, raising concerns about their potential toxic effects. In the present study, we determined the bioaccumulation potential of bisphenol A (BPA) in adult zebrafish (Danio rerio) in the absence and presence of nano-sized plastic particles (nanoplastics, NPPs). Results show that BPA can accumulate in the viscera, gill, head and muscle of zebrafish with 85, 43, 20, and 3μg/g ww after 1d exposure. NPPs were also found to accumulate in different tissues of the fish. Relative equilibrium was reached after 1d exposure in different tissues with 39 to 636mg/kg ww. Co-exposure of NPPs and BPA led to a 2.2 and 2.6-fold significant increment of BPA uptake in the head and viscera, if compared with BPA alone treatment after 3d exposure. As such, we further investigated several neurotoxic biomarker alterations in the fish head. It was found that either BPA or NPPs can cause myelin basic protein (MBP)/gene up-regulation in the central nervous system (CNS); meanwhile, both contaminants exhibited significant inhibition of acetylcholinesterase (AChE) activity, which is a well-known representative biomarker for neurotoxicity. Moreover, for the co-exposure treatment, biomarkers of myeline and tubulin protein/gene expressions, dopamine content, and the mRNA expression of mesencephalic astrocyte derived neurotrophic factor (MANF) were all significantly up-regulated, suggesting that an enhanced neurotoxic effects in both CNS and dopaminergic system occurred. However, AChE activity was no more inhibited in the co-exposure treatment, which implies that solely AChE measurement may not be sufficient to identify neurotoxic effects in the cholinergic system. Overall, the present study demonstrates that the presence of NPPs can increase BPA bioavailability and cause neurotoxicity in adult zebrafish.
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Affiliation(s)
- Qiqing Chen
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, PR China; Institute for Environmental Research, Department of Ecosystem Analysis, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Siping Road 1239, Shanghai 200092, PR China
| | - Daqiang Yin
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, PR China.
| | - Yunlu Jia
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sabrina Schiwy
- Institute for Environmental Research, Department of Ecosystem Analysis, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Jessica Legradi
- Institute for Environmental Studies, Vrije University Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Shouye Yang
- State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Siping Road 1239, Shanghai 200092, PR China
| | - Henner Hollert
- State Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092, PR China; Institute for Environmental Research, Department of Ecosystem Analysis, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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103
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Wu Q, Yan W, Cheng H, Liu C, Hung TC, Guo X, Li G. Parental transfer of microcystin-LR induced transgenerational effects of developmental neurotoxicity in zebrafish offspring. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 231:471-478. [PMID: 28837927 DOI: 10.1016/j.envpol.2017.08.038] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/26/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
Microcystin-LR (MCLR) has been reported to cause developmental neurotoxicity in zebrafish, but there are few studies on the mechanisms of MCLR-induced transgenerational effects of developmental neurotoxicity. In this study, zebrafish were exposed to 0, 1, 5, and 25 μg/L MCLR for 60 days. The F1 zebrafish embryos from the above-mentioned parents were collected and incubated in clean water for 120 h for hatching. After examining the parental zebrafish and F1 embryos, MCLR was detected in the gonad of adults and F1 embryos, indicating MCLR could potentially be transferred from parents to offspring. The larvae also showed a serious hypoactivity. The contents of dopamine, dihydroxyphenylacetic acid (DOPAC), serotonin, gamma-aminobutyric acid (GABA) and acetylcholine (ACh) were further detected, but only the first three neurotransmitters showed significant reduction in the 5 and 25 μg/L MCLR parental exposure groups. In addition, the acetylcholinesterase (AChE) activity was remarkably decreased in MCLR parental exposure groups, while the expression levels of manf, bdnf, ache, htr1ab, htr1b, htr2a, htr1aa, htr5a, DAT, TH1 and TH2 genes coincided with the decreased content of neurotransmitters (dopamine, DOPAC and serotonin) and the activity of AChE. Neuronal development related genes, α1-tubulin, syn2a, mbp, gfap, elavl3, shha and gap43 were also measured, but gap43 was the gene only up-regulated. Our results demonstrated MCLR could be transferred to offspring, and subsequently induce developmental neurotoxicity in F1 zebrafish larvae by disturbing the neurotransmitter systems and neuronal development.
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Affiliation(s)
- Qin Wu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China
| | - Wei Yan
- Institute of Agricultural Quality Standards & Testing Technology, Hubei Academy of Agricultural Sciences, Wuhan 430064, PR China
| | - Houcheng Cheng
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Tien-Chieh Hung
- Department of Biological and Agricultural Engineering, University of California-Davis, Davis, CA 95616, USA
| | - Xiaochun Guo
- Chinese Research Academy of Environmental Science, State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, Beijing 100012, PR China
| | - Guangyu Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, PR China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, PR China; National Demonstration Center for Experimental Aquaculture Education (Huazhong Agricultural University), Wuhan 430070, PR China.
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104
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Chen L, Wang X, Zhang X, Lam PKS, Guo Y, Lam JCW, Zhou B. Transgenerational endocrine disruption and neurotoxicity in zebrafish larvae after parental exposure to binary mixtures of decabromodiphenyl ether (BDE-209) and lead. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017. [PMID: 28649046 DOI: 10.1016/j.envpol.2017.06.053] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) and heavy metals are two key groups of electric and electronic equipment contaminants. Despite their co-occurrence in aquatic environments, their combined effects remain largely unknown, particularly under a chronic exposure regime. In the present study, adult zebrafish (Danio rerio) were exposed to environmentally relevant concentrations of BDE-209 and lead (Pb), or their binary mixtures, for 3 months. After chronic parental exposure, increased transfer of BDE-209 and Pb to the offspring eggs was activated in the coexposure groups, with BDE-197 being the predominant PBDE congener, indicating the dynamic metabolism of BDE-209 in parental zebrafish. In the presence of Pb, culturing the eggs in clean water until 5 days post-fertilization (dpf) further accelerated the debromination of BDE-209 towards BDE-197 in the offspring, caused by the preferential removal of bromine atoms at meta positions. BDE-209 and Pb combinations induced reproductive and thyroid endocrine disruption in adults, which resulted in an imbalanced deposition of hormones in the eggs. However, compared with single chemical exposure, the larval offspring at 5 dpf from the coexposure groups had reversed the adverse influences from maternal origin. In addition, the interaction between BDE-209 and Pb led to transgenerational developmental neurotoxicity in the larval offspring, where inhibited neuronal growth and neurotransmitter signaling, disorganized muscular assembly, and impaired visual function contributed to the observed neurobehavioral deficits. Overall, depending on specific biological events, the complex interaction between BDE-209 and Pb under chronic exposure resulted in significant alterations in their environmental fate and toxicological actions, thus complicating the accurate evaluation of ecological risks and constituting an unquantified threat to environmental safety.
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Affiliation(s)
- Lianguo Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Xianfeng Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Xiaohua Zhang
- Department of Science and Environmental Studies, The Education University of Hong Kong, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong, China
| | - Paul K S Lam
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Yongyong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - James C W Lam
- State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China; Department of Science and Environmental Studies, The Education University of Hong Kong, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong, China.
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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105
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Whole Genome Sequencing-Based Mapping and Candidate Identification of Mutations from Fixed Zebrafish Tissue. G3-GENES GENOMES GENETICS 2017; 7:3415-3425. [PMID: 28855284 PMCID: PMC5633390 DOI: 10.1534/g3.117.300212] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
As forward genetic screens in zebrafish become more common, the number of mutants that cannot be identified by gross morphology or through transgenic approaches, such as many nervous system defects, has also increased. Screening for these difficult-to-visualize phenotypes demands techniques such as whole-mount in situ hybridization (WISH) or antibody staining, which require tissue fixation. To date, fixed tissue has not been amenable for generating libraries for whole genome sequencing (WGS). Here, we describe a method for using genomic DNA from fixed tissue and a bioinformatics suite for WGS-based mapping of zebrafish mutants. We tested our protocol using two known zebrafish mutant alleles, gpr126st49 and egr2bfh227, both of which cause myelin defects. As further proof of concept we mapped a novel mutation, stl64, identified in a zebrafish WISH screen for myelination defects. We linked stl64 to chromosome 1 and identified a candidate nonsense mutation in the F-box and WD repeat domain containing 7 (fbxw7) gene. Importantly, stl64 mutants phenocopy previously described fbxw7vu56 mutants, and knockdown of fbxw7 in wild-type animals produced similar defects, demonstrating that stl64 disrupts fbxw7. Together, these data show that our mapping protocol can map and identify causative lesions in mutant screens that require tissue fixation for phenotypic analysis.
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106
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Cholesterol Biosynthesis Supports Myelin Gene Expression and Axon Ensheathment through Modulation of P13K/Akt/mTor Signaling. J Neurosci 2017; 36:7628-39. [PMID: 27445141 DOI: 10.1523/jneurosci.0726-16.2016] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/06/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Myelin, which ensheaths and insulates axons, is a specialized membrane highly enriched with cholesterol. During myelin formation, cholesterol influences membrane fluidity, associates with myelin proteins such as myelin proteolipid protein, and assembles lipid-rich microdomains within membranes. Surprisingly, cholesterol also is required by oligodendrocytes, glial cells that make myelin, to express myelin genes and wrap axons. How cholesterol mediates these distinct features of oligodendrocyte development is not known. One possibility is that cholesterol promotes myelination by facilitating signal transduction within the cell, because lipid-rich microdomains function as assembly points for signaling molecules. Signaling cascades that localize to cholesterol-rich regions of the plasma membrane include the PI3K/Akt pathway, which acts upstream of mechanistic target of rapamycin (mTOR), a major driver of myelination. Through manipulation of cholesterol levels and PI3K/Akt/mTOR signaling in zebrafish, we discovered that mTOR kinase activity in oligodendrocytes requires cholesterol. Drawing on a combination of pharmacological and rescue experiments, we provide evidence that mTOR kinase activity is required for cholesterol-mediated myelin gene expression. On the other hand, cholesterol-dependent axon ensheathment is mediated by Akt signaling, independent of mTOR kinase activity. Our data reveal that cholesterol-dependent myelin gene expression and axon ensheathment are facilitated by distinct signaling cascades downstream of Akt. Because mTOR promotes cholesterol synthesis, our data raise the possibility that cholesterol synthesis and mTOR signaling engage in positive feedback to promote the formation of myelin membrane. SIGNIFICANCE STATEMENT The speed of electrical impulse movement through axons is increased by myelin, a specialized, cholesterol-rich glial cell membrane that tightly wraps axons. During development, myelin membrane grows dramatically, suggesting a significant demand on mechanisms that produce and assemble myelin components, while it spirally wraps axons. Our studies indicate that cholesterol is necessary for both myelin growth and axon wrapping. Specifically, we found that cholesterol facilitates signaling mediated by the PI3K/Akt/mTOR pathway, a powerful driver of myelination. Because mTOR promotes the expression of genes necessary for cholesterol synthesis, cholesterol formation and PI3K/Akt/mTOR signaling might function as a feedforward mechanism to produce the large amounts of myelin membrane necessary for axon ensheathment.
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107
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Delfino-Machín M, Madelaine R, Busolin G, Nikaido M, Colanesi S, Camargo-Sosa K, Law EWP, Toppo S, Blader P, Tiso N, Kelsh RN. Sox10 contributes to the balance of fate choice in dorsal root ganglion progenitors. PLoS One 2017; 12:e0172947. [PMID: 28253350 PMCID: PMC5333849 DOI: 10.1371/journal.pone.0172947] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 02/12/2017] [Indexed: 11/19/2022] Open
Abstract
The development of functional peripheral ganglia requires a balance of specification of both neuronal and glial components. In the developing dorsal root ganglia (DRGs), these components form from partially-restricted bipotent neuroglial precursors derived from the neural crest. Work in mouse and chick has identified several factors, including Delta/Notch signaling, required for specification of a balance of these components. We have previously shown in zebrafish that the Sry-related HMG domain transcription factor, Sox10, plays an unexpected, but crucial, role in sensory neuron fate specification in vivo. In the same study we described a novel Sox10 mutant allele, sox10baz1, in which sensory neuron numbers are elevated above those of wild-types. Here we investigate the origin of this neurogenic phenotype. We demonstrate that the supernumerary neurons are sensory neurons, and that enteric and sympathetic neurons are almost absent just as in classical sox10 null alleles; peripheral glial development is also severely abrogated in a manner similar to other sox10 mutant alleles. Examination of proliferation and apoptosis in the developing DRG reveals very low levels of both processes in wild-type and sox10baz1, excluding changes in the balance of these as an explanation for the overproduction of sensory neurons. Using chemical inhibition of Delta-Notch-Notch signaling we demonstrate that in embryonic zebrafish, as in mouse and chick, lateral inhibition during the phase of trunk DRG development is required to achieve a balance between glial and neuronal numbers. Importantly, however, we show that this mechanism is insufficient to explain quantitative aspects of the baz1 phenotype. The Sox10(baz1) protein shows a single amino acid substitution in the DNA binding HMG domain; structural analysis indicates that this change is likely to result in reduced flexibility in the HMG domain, consistent with sequence-specific modification of Sox10 binding to DNA. Unlike other Sox10 mutant proteins, Sox10(baz1) retains an ability to drive neurogenin1 transcription. We show that overexpression of neurogenin1 is sufficient to produce supernumerary DRG sensory neurons in a wild-type background, and can rescue the sensory neuron phenotype of sox10 morphants in a manner closely resembling the baz1 phenotype. We conclude that an imbalance of neuronal and glial fate specification results from the Sox10(baz1) protein's unique ability to drive sensory neuron specification whilst failing to drive glial development. The sox10baz1 phenotype reveals for the first time that a Notch-dependent lateral inhibition mechanism is not sufficient to fully explain the balance of neurons and glia in the developing DRGs, and that a second Sox10-dependent mechanism is necessary. Sox10 is thus a key transcription factor in achieving the balance of sensory neuronal and glial fates.
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Affiliation(s)
- Mariana Delfino-Machín
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
| | - Romain Madelaine
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Masataka Nikaido
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
| | - Sarah Colanesi
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
| | - Karen Camargo-Sosa
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
| | - Edward W. P. Law
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
| | - Stefano Toppo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Patrick Blader
- Centre de Biologie du Développement (CBD, UMR5547), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Natascia Tiso
- Department of Biology, University of Padova, Padova, Italy
| | - Robert N. Kelsh
- Department of Biology and Biochemistry and Centre for Regenerative Medicine, University of Bath, Bath, United Kingdom
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108
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Sleigh JN, Vagnoni A, Twelvetrees AE, Schiavo G. Methodological advances in imaging intravital axonal transport. F1000Res 2017; 6:200. [PMID: 28344778 PMCID: PMC5333613 DOI: 10.12688/f1000research.10433.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/27/2017] [Indexed: 11/25/2022] Open
Abstract
Axonal transport is the active process whereby neurons transport cargoes such as organelles and proteins anterogradely from the cell body to the axon terminal and retrogradely in the opposite direction. Bi-directional transport in axons is absolutely essential for the functioning and survival of neurons and appears to be negatively impacted by both aging and diseases of the nervous system, such as Alzheimer’s disease and amyotrophic lateral sclerosis. The movement of individual cargoes along axons has been studied
in vitro in live neurons and tissue explants for a number of years; however, it is currently unclear as to whether these systems faithfully and consistently replicate the
in vivo situation. A number of intravital techniques originally developed for studying diverse biological events have recently been adapted to monitor axonal transport in real-time in a range of live organisms and are providing novel insight into this dynamic process. Here, we highlight these methodological advances in intravital imaging of axonal transport, outlining key strengths and limitations while discussing findings, possible improvements, and outstanding questions.
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Affiliation(s)
- James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
| | - Alessio Vagnoni
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Alison E Twelvetrees
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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109
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He X, Gao J, Dong T, Chen M, Zhou K, Chang C, Luo J, Wang C, Wang S, Chen D, Zhou Z, Tian Y, Xia Y, Wang X. Developmental Neurotoxicity of Methamidophos in the Embryo-Larval Stages of Zebrafish. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 14:ijerph14010023. [PMID: 28036051 PMCID: PMC5295274 DOI: 10.3390/ijerph14010023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/20/2016] [Accepted: 12/26/2016] [Indexed: 12/02/2022]
Abstract
Methamidophos is a representative organophosphate insecticide. The knowledge of its developmental neurotoxicity is limited, especially for zebrafish in the early stages of their life. Four hour post-fertilization (hpf) zebrafish embryos were exposed to several environmentally relevant concentrations of methamidophos (0, 25, and 500 μg/L) for up to 72 hpf. Locomotor behavior was then studied in the zebrafish larvae at this timepoint. Acridine orange (AO) staining was carried out in the zebrafish larvae, and the mRNA levels of genes associated with neural development (mbp and syn2a) were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The number of escape responders for mechanical stimulation was significantly decreased in exposed groups. AO staining showed noticeable signs of apoptosis mainly in the brain. In addition, the mRNA levels of mbp and syn2a were both significantly down-regulated in exposed groups. Our study provides the first evidence that methamidophos exposure can cause developmental neurotoxicity in the early stages of zebrafish life, which may be caused by the effect of methamidophos on neurodevelopmental genes and the activation of cell apoptosis in the brain.
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Affiliation(s)
- Xiaowei He
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Jiawei Gao
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Tianyu Dong
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Minjian Chen
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Wuxi Maternal and Child Health Hospital, Nanjing Medical University, Wuxi 214002, China.
| | - Kun Zhou
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Chunxin Chang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Jia Luo
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Chao Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Shoulin Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Daozhen Chen
- Wuxi Maternal and Child Health Hospital, Nanjing Medical University, Wuxi 214002, China.
| | - Zuomin Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China.
| | - Ying Tian
- MOE and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.
- Department of Environmental Health, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Xinru Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
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110
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Abstract
Myelination by oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system is essential for nervous system function and health. Despite its importance, we have a relatively poor understanding of the molecular and cellular mechanisms that regulate myelination in the living animal, particularly in the CNS. This is partly due to the fact that myelination commences around birth in mammals, by which time the CNS is complex and largely inaccessible, and thus very difficult to image live in its intact form. As a consequence, in recent years much effort has been invested in the use of smaller, simpler, transparent model organisms to investigate mechanisms of myelination in vivo. Although the majority of such studies have employed zebrafish, the Xenopus tadpole also represents an important complementary system with advantages for investigating myelin biology in vivo. Here we review how the natural features of zebrafish embryos and larvae and Xenopus tadpoles make them ideal systems for experimentally interrogating myelination by live imaging. We outline common transgenic technologies used to generate zebrafish and Xenopus that express fluorescent reporters, which can be used to image myelination. We also provide an extensive overview of the imaging modalities most commonly employed to date to image the nervous system in these transparent systems, and also emerging technologies that we anticipate will become widely used in studies of zebrafish and Xenopus myelination in the near future.
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Affiliation(s)
- Jenea M Bin
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - David A Lyons
- Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
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111
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Tingaud-Sequeira A, Raldúa D, Lavie J, Mathieu G, Bordier M, Knoll-Gellida A, Rambeau P, Coupry I, André M, Malm E, Möller C, Andreasson S, Rendtorff ND, Tranebjærg L, Koenig M, Lacombe D, Goizet C, Babin PJ. Functional validation of ABHD12 mutations in the neurodegenerative disease PHARC. Neurobiol Dis 2016; 98:36-51. [PMID: 27890673 DOI: 10.1016/j.nbd.2016.11.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 10/25/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022] Open
Abstract
ABHD12 mutations have been linked to neurodegenerative PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa, and early-onset cataract), a rare, progressive, autosomal, recessive disease. Although ABHD12 is suspected to play a role in the lysophosphatidylserine and/or endocannabinoid pathways, its precise functional role(s) leading to PHARC disease had not previously been characterized. Cell and zebrafish models were designed to demonstrate the causal link between an identified new missense mutation p.T253R, characterized in ABHD12 from a young patient, the previously characterized p.T202I and p.R352* mutations, and the associated PHARC. Measuring ABHD12 monoacylglycerol lipase activity in transfected HEK293 cells demonstrated inhibition with mutated isoforms. Both the expression pattern of zebrafish abhd12 and the phenotype of specific antisense morpholino oligonucleotide gene knockdown morphants were consistent with human PHARC hallmarks. High abhd12 transcript levels were found in the optic tectum and tract, colocalized with myelin basic protein, and in the spinal cord. Morphants have myelination defects and concomitant functional deficits, characterized by progressive ataxia and motor skill impairment. A disruption of retina architecture and retinotectal projections was observed, together with an inhibition of lens clarification and a low number of mechanosensory hair cells in the inner ear and lateral line system. The severe phenotypes in abhd12 knockdown morphants were rescued by introducing wild-type human ABHD12 mRNA, but not by mutation-harboring mRNAs. Zebrafish may provide a suitable vertebrate model for ABHD12 insufficiency and the study of functional impairment and potential therapeutic rescue of this rare, neurodegenerative disease.
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Affiliation(s)
- Angèle Tingaud-Sequeira
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | | | - Julie Lavie
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Guilaine Mathieu
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Magali Bordier
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France; CHU Bordeaux, Hôpital Pellegrin, Service de Génétique Médicale, Bordeaux, France
| | - Anja Knoll-Gellida
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Pierre Rambeau
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Isabelle Coupry
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Michèle André
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France
| | - Eva Malm
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden
| | - Claes Möller
- School of Medicine and Health, Örebro University, Sweden
| | - Sten Andreasson
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden
| | - Nanna D Rendtorff
- Department Audiology, Bispebjerg Hospital/Rigshospitalet, Department of Clinical Genetics, Rigshospitalet/The Kennedy Center, University of Copenhagen, Institute for Clinical Medicine Copenhagen, Denmark
| | - Lisbeth Tranebjærg
- Department Audiology, Bispebjerg Hospital/Rigshospitalet, Department of Clinical Genetics, Rigshospitalet/The Kennedy Center, University of Copenhagen, Institute for Clinical Medicine Copenhagen, Denmark
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire et unité INSERM UMR_S827, IURC, Montpellier, France
| | - Didier Lacombe
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France; CHU Bordeaux, Hôpital Pellegrin, Service de Génétique Médicale, Bordeaux, France
| | - Cyril Goizet
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France; CHU Bordeaux, Hôpital Pellegrin, Service de Génétique Médicale, Bordeaux, France
| | - Patrick J Babin
- Univ. Bordeaux, INSERM U1211, Maladies Rares: Génétique et Métabolisme (MRGM), F-33076 Bordeaux, France.
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112
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Pinzon-Olejua A, Welte C, Chekuru A, Bosak V, Brand M, Hans S, Stuermer CAO. Cre-inducible site-specific recombination in zebrafish oligodendrocytes. Dev Dyn 2016; 246:41-49. [PMID: 27666728 DOI: 10.1002/dvdy.24458] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/18/2016] [Accepted: 08/29/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND The conditional Cre/lox system has recently emerged as a valuable tool for studies on both embryonic and adult Zebrafish. Temporal control and site-specific recombination are achieved by using the ligand-inducible CreERT2 and administration of the drug tamoxifen (TAM) or its active metabolite, 4-Hydroxytamoxifen (4-OHT). RESULTS Here we report the generation of a transgenic Zebrafish line, which expresses an mCherry-tagged variant of CreERT2 under the control of the myelin basic protein a (mbpa) promoter. Our analysis shows that larval and adult expression of the transgene recapitulates the endogenous mbpa expression pattern in oligodendrocytes. Furthermore, combination with a Cre-dependent EGFP reporter results in EGFP-expressing oligodendrocytes in the spinal cord, brain, and optic nerve in TAM- or 4-OHT-treated larvae and 4-month-old fish, but not in untreated controls. CONCLUSIONS The transgenic Zebrafish line Tg(mbpa:mCherry-T2A-CreERT2 ) elicits CreERT2 expression specifically in myelinating glia cells. Cre-inducible targeted recombination of genes in oligodendrocytes will be useful to elucidate cellular and molecular mechanisms of myelination in vivo during development (myelination) and regeneration (remyelination) after injury to the central nervous system (CNS). It will also allow targeted expression and overexpression of genes of interest (transgenes) in oligodendrocytes at defined developmental and adult stages. Developmental Dynamics 246:41-49, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alejandro Pinzon-Olejua
- Department of Biology, University of Konstanz, Universitätsstraße 10, Konstanz, 78457, Germany.,Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, 60438, Frankfurt am Main, Germany
| | - Cornelia Welte
- Department of Biology, University of Konstanz, Universitätsstraße 10, Konstanz, 78457, Germany
| | - Avinash Chekuru
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstr. 105, 01307, Dresden, Germany
| | - Viktoria Bosak
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstr. 105, 01307, Dresden, Germany
| | - Michael Brand
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstr. 105, 01307, Dresden, Germany
| | - Stefan Hans
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Fetscherstr. 105, 01307, Dresden, Germany
| | - Claudia A O Stuermer
- Department of Biology, University of Konstanz, Universitätsstraße 10, Konstanz, 78457, Germany
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Abstract
Myelin is a lipid-rich sheath formed by the spiral wrapping of specialized glial cells around axon segments. Myelinating glia allow for rapid transmission of nerve impulses and metabolic support of axons, and the absence of or disruption to myelin results in debilitating motor, cognitive, and emotional deficits in humans. Because myelin is a jawed vertebrate innovation, zebrafish are one of the simplest vertebrate model systems to study the genetics and development of myelinating glia. The morphogenetic cellular movements and genetic program that drive myelination are conserved between zebrafish and mammals, and myelin develops rapidly in zebrafish larvae, within 3-5days postfertilization. Myelin ultrastructure can be visualized in the zebrafish from larval to adult stages via transmission electron microscopy, and the dynamic development of myelinating glial cells may be observed in vivo via transgenic reporter lines in zebrafish larvae. Zebrafish are amenable to genetic and pharmacological screens, and screens for myelinating glial phenotypes have revealed both genes and drugs that promote myelin development, many of which are conserved in mammalian glia. Recently, zebrafish have been employed as a model to understand the complex dynamics of myelinating glia during development and regeneration. In this chapter, we describe these key methodologies and recent insights into mechanisms that regulate myelination using the zebrafish model.
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Affiliation(s)
- M D'Rozario
- Washington University School of Medicine, St. Louis, MO, United States
| | - K R Monk
- Washington University School of Medicine, St. Louis, MO, United States; Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States
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Zada D, Tovin A, Lerer-Goldshtein T, Appelbaum L. Pharmacological treatment and BBB-targeted genetic therapy for MCT8-dependent hypomyelination in zebrafish. Dis Model Mech 2016; 9:1339-1348. [PMID: 27664134 PMCID: PMC5117236 DOI: 10.1242/dmm.027227] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/19/2016] [Indexed: 12/31/2022] Open
Abstract
Hypomyelination is a key symptom of Allan-Herndon-Dudley syndrome (AHDS), a psychomotor retardation associated with mutations in the thyroid-hormone (TH) transporter MCT8 (monocarboxylate transporter 8). AHDS is characterized by severe intellectual deficiency, neuromuscular impairment and brain hypothyroidism. In order to understand the mechanism for TH-dependent hypomyelination, we developed an mct8 mutant (mct8-/-) zebrafish model. The quantification of genetic markers for oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes revealed reduced differentiation of OPCs into oligodendrocytes in mct8-/- larvae and adults. Live imaging of single glial cells showed that the number of oligodendrocytes and the length of their extensions are reduced, and the number of peripheral Schwann cells is increased, in mct8-/- larvae compared with wild type. Pharmacological analysis showed that TH analogs and clemastine partially rescued the hypomyelination in the CNS of mct8-/- larvae. Intriguingly, triiodothyronine (T3) treatment rescued hypomyelination in mct8-/- embryos before the maturation of the blood-brain barrier (BBB), but did not affect hypomyelination in older larvae. Thus, we expressed Mct8-tagRFP in the endothelial cells of the vascular system and showed that even relatively weak mosaic expression completely rescued hypomyelination in mct8-/- larvae. These results suggest potential pharmacological treatments and BBB-targeted gene therapy that can enhance myelination in AHDS and possibly in other TH-dependent brain disorders.
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Affiliation(s)
- David Zada
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Adi Tovin
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Tali Lerer-Goldshtein
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lior Appelbaum
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
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115
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Asad Z, Pandey A, Babu A, Sun Y, Shevade K, Kapoor S, Ullah I, Ranjan S, Scaria V, Bajpai R, Sachidanandan C. Rescue of neural crest-derived phenotypes in a zebrafish CHARGE model by Sox10 downregulation. Hum Mol Genet 2016; 25:3539-3554. [PMID: 27418670 PMCID: PMC5179949 DOI: 10.1093/hmg/ddw198] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 05/27/2016] [Accepted: 06/20/2016] [Indexed: 12/20/2022] Open
Abstract
CHD7 mutations are implicated in a majority of cases of the congenital disorder, CHARGE syndrome. CHARGE, an autosomal dominant syndrome, is known to affect multiple tissues including eye, heart, ear, craniofacial nerves and skeleton and genital organs. Using a morpholino-antisense-oligonucleotide-based zebrafish model for CHARGE syndrome, we uncover a complex spectrum of abnormalities in the neural crest and the crest-derived cell types. We report for the first time, defects in myelinating Schwann cells, enteric neurons and pigment cells in a CHARGE model. We also observe defects in the specification of peripheral neurons and the craniofacial skeleton as previously reported. Chd7 morphants have impaired migration of neural crest cells and deregulation of sox10 expression from the early stages. Knocking down Sox10 in the zebrafish CHARGE model rescued the defects in Schwann cells and craniofacial cartilage. Our zebrafish CHARGE model thus reveals important regulatory roles for Chd7 at multiple points of neural crest development viz., migration, fate choice and differentiation and we suggest that sox10 deregulation is an important driver of the neural crest-derived aspects of Chd7 dependent CHARGE syndrome.
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Affiliation(s)
- Zainab Asad
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India and
| | - Aditi Pandey
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
| | - Aswini Babu
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India and
| | - Yuhan Sun
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry and Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Kaivalya Shevade
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry and Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Shruti Kapoor
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India and
| | - Ikram Ullah
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
| | - Shashi Ranjan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
| | - Vinod Scaria
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India and
| | - Ruchi Bajpai
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry and Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Chetana Sachidanandan
- CSIR-Institute of Genomics & Integrative Biology, South Campus, New Delhi, 110025, India
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110025, India and
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116
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Lei XD, Sun Y, Cai SJ, Fang YW, Cui JL, Li YH. Role of tumor necrosis factor-alpha in zebrafish retinal neurogenesis and myelination. Int J Ophthalmol 2016; 9:831-7. [PMID: 27366683 DOI: 10.18240/ijo.2016.06.07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 02/23/2016] [Indexed: 12/16/2022] Open
Abstract
AIM To investigate the role of tumor necrosis factor-alpha (TNF-α) in zebrafish retinal development and myelination. METHODS Morpholino oligonucleotides (MO), which are complementary to the translation start site of the wild-type embryonic zebrafish TNF-α mRNA sequence, were synthesized and injected into one- to four-cell embryos. The translation blocking specificity was verified by Western blotting using an anti-TNF-α antibody, whole-mount in situ hybridization using a hepatocyte-specific mRNA probe ceruloplasmin (cp), and co-injection of TNF-α MO and TNF-α mRNA. An atonal homolog 7 (atoh7) mRNA probe was used to detect neurogenesis onset. The retinal neurodifferentiation was analyzed by immunohistochemistry using antibodies Zn12, Zpr1, and Zpr3 to label ganglion cells, cones, and rods, respectively. Myelin basic protein (mbp) was used as a marker to track and observe the myelination using whole-mount in situ hybridization. RESULTS Targeted knockdown of TNF-α resulted in specific suppression of TNF-α expression and a severely underdeveloped liver. The co-injection of TNF-α MO and mRNA rescued the liver development. Retinal neurogenesis in TNF-α morphants was initiated on time. The retina was fully laminated, while ganglion cells, cones, and rods were well differentiated at 72 hours post-fertilization (hpf). mbp was expressed in Schwann cells in the lateral line nerves and cranial nerves from 3 days post-fertilization (dpf) as well as in oligodendrocytes linearly along the hindbrain bundles and the spinal cord from 4 dpf, which closely resembled its endogenous profile. CONCLUSION TNF-α is not an essential regulator for retinal neurogenesis and optic myelination.
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Affiliation(s)
- Xu-Dan Lei
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Yan Sun
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Shi-Jiao Cai
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Yang-Wu Fang
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Jian-Lin Cui
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Yu-Hao Li
- Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
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Wu Q, Yan W, Liu C, Li L, Yu L, Zhao S, Li G. Microcystin-LR exposure induces developmental neurotoxicity in zebrafish embryo. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:793-800. [PMID: 27038211 DOI: 10.1016/j.envpol.2016.03.048] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/18/2016] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
Microcystin-LR (MCLR) is a commonly acting potent hepatotoxin and has been pointed out of potentially causing developmental neurotoxicity, but the exact mechanism is little known. In this study, zebrafish embryos were exposed to 0, 0.8, 1.6 or 3.2 mg/L MCLR for 120 h. MCLR exposure through submersion caused serious hatching delay and body length decrease. The content of MCLR in zebrafish larvae was analyzed and the results demonstrated that MCLR can accumulate in zebrafish larvae. The locomotor speed of zebrafish larvae was decreased. Furthermore, the dopamine and acetylcholine (ACh) content were detected to be significantly decreased in MCLR exposure groups. And the acetylcholinesterase (AChE) activity was significantly increased after exposure to 1.6 and 3.2 mg/L MCLR. The transcription pattern of manf, chrnα7 and ache gene was consistent with the change of the dopamine content, ACh content and AChE activity. Gene expression involved in the development of neurons was also measured. ɑ1-tubulin and shha gene expression were down-regulated, whereas mbp and gap43 gene expression were observed to be significantly up-regulated upon exposure to MCLR. The above results indicated that MCLR-induced developmental toxicity might attribute to the disorder of cholinergic system, dopaminergic signaling, and the development of neurons.
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Affiliation(s)
- Qin Wu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China
| | - Wei Yan
- Institute of Agricultural Quality Standards & Testing Technology, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Chunsheng Liu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Li Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China
| | - Liqin Yu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Sujuan Zhao
- School of Public Health, Anhui Medical University, Hefei 230032, China
| | - Guangyu Li
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, PR China.
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118
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Jin Y, Zhu Z, Wang Y, Yang E, Feng X, Fu Z. The fungicide imazalil induces developmental abnormalities and alters locomotor activity during early developmental stages in zebrafish. CHEMOSPHERE 2016; 153:455-461. [PMID: 27035382 DOI: 10.1016/j.chemosphere.2016.03.085] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
The fungicide imazalil (IMZ) is used extensively to protect vegetable fields, fruit plantations and post-harvest crops from rot. Likely due to its wide-spread use, IMZ is frequently detected in vegetable, fruit, soil and even surface water samples. Even though several previous studies have reported on the neurotoxicity of IMZ, its effects on the neurobehavior of zebrafish have received little attention to date. In this study, we show that the heartbeat and hatchability of zebrafish were significantly influenced by IMZ concentrations of 300 μg L(-1) or higher. Moreover, in zebrafish larvae, locomotor behaviors such as average swimming speed and swimming distance were significantly decreased after exposure to 300 μg L(-1) IMZ for 96 h, and acetylcholinesterase (AChE) expression and activity were consistently inhibited in IMZ-treated fish. Our results further suggest that IMZ could act as a neuroendocrine disruptor by decreasing the expression of neurotoxicity-related genes such as Glial fibrillary acidic protein (Gfap), Myelin basic protein (Mbp) and Sonic hedgehog a (Shha) during early developmental stages of zebrafish. In conclusion, we show that exposure to IMZ has the potential to induce developmental toxicity and locomotor behavior abnormalities during zebrafish development.
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Affiliation(s)
- Yuanxiang Jin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhihong Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yueyi Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Enlu Yang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiayan Feng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China.
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119
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Monaco A, Grimaldi MC, Ferrandino I. Neuroglial alterations in the zebrafish brain exposed to cadmium chloride. J Appl Toxicol 2016; 36:1629-1638. [PMID: 27080906 DOI: 10.1002/jat.3328] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/07/2016] [Accepted: 03/07/2016] [Indexed: 12/15/2022]
Abstract
Cadmium is an extremely toxic heavy metal that widely occurs in industrial workplaces with various hazardous effects on brain functions. The cytotoxic effects of cadmium chloride (CdCl2 ) on the neuroglial components of the zebrafish brain were analysed by detecting the glial fibrillary acidic protein (GFAP) expression and the mRNA levels of myelin genes mbp, mpz and plp1 in adult specimens exposed to cadmium for 2, 7 and 16 days. A significant decrease in the GFAP protein by Western blotting experiments was observed after 2 days of treatment, reaching 55% after 16 days. No change was observed in the mRNA levels. Using immunohistochemistry, a reduction in GFAP-positive structures was revealed with a progressive trend in all the brains at 2, 7 and 16 days of treatment. In particular, a considerable reduction in GFAP-positive fibres, with a different course, was observed in the ventricle areas and at the pial surface and in blood vessels after 16 days. Our experiments also showed a structural and chemical alteration of myelin and upregulation of mpz mRNA levels, the oligodendrocyte gene that is upregulated in experiments of neuronal injury, but not of plp1 and mbp mRNA levels, other myelin structural genes. These data confirm the toxic action of cadmium on the zebrafish brain. This action is time-dependent and involves the glial cells, key components of the protection and function of nerve cells, hence the basis for many neurological diseases. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Antonio Monaco
- University of Naples Federico II, Department of Biology, Naples, Italy
| | - Maria C Grimaldi
- University of Naples Federico II, Department of Biology, Naples, Italy
| | - Ida Ferrandino
- University of Naples Federico II, Department of Biology, Naples, Italy.
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120
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Liu Z, Wang Y, Zhu Z, Yang E, Feng X, Fu Z, Jin Y. Atrazine and its main metabolites alter the locomotor activity of larval zebrafish (Danio rerio). CHEMOSPHERE 2016; 148:163-170. [PMID: 26803580 DOI: 10.1016/j.chemosphere.2016.01.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/03/2016] [Accepted: 01/04/2016] [Indexed: 06/05/2023]
Abstract
Atrazine (ATZ) and its main chlorometabolites, i.e., diaminochlorotriazine (DACT), deisopropylatrazine (DIP), and deethylatrazine (DE), have been widely detected in aquatic systems near agricultural fields. However, their possible effects on aquatic animals are still not fully understood. In this study, it was observed that several developmental endpoints such as the heart beat, hatchability, and morphological abnormalities were influenced by ATZ and its metabolites in different developmental stages. In addition, after 5 days of exposure to 30, 100, 300 μg L(-1) ATZ and its main chlorometabolites, the swimming behaviors of larval zebrafish were significantly disturbed, and the acetylcholinesterase (AChE) activities were consistently inhibited. Our results also demonstrate that ATZ and its main chlorometabolites are neuroendocrine disruptors that impact the expression of neurotoxicity-related genes such as Ache, Gap43, Gfap, Syn2a, Shha, Mbp, Elavl3, Nestin and Ngn1 in early developmental stages of zebrafish. According to our results, it is possible that not only ATZ but also its metabolites (DACT, DIP and DE) have the same or even more toxic effects on different endpoints of the early developmental stages of zebrafish.
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Affiliation(s)
- Zhenzhen Liu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yueyi Wang
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhihong Zhu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Enlu Yang
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiayan Feng
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhengwei Fu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yuanxiang Jin
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
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Wang X, Yang L, Wang Q, Guo Y, Li N, Ma M, Zhou B. The neurotoxicity of DE-71: effects on neural development and impairment of serotonergic signaling in zebrafish larvae. J Appl Toxicol 2016; 36:1605-1613. [PMID: 27001416 DOI: 10.1002/jat.3322] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 01/29/2023]
Abstract
The underlying mechanism of polybrominated diphenyl ether (PBDE)-induced neurotoxicity is still a major concern due to its ubiquitous nature and persistence. Here, zebrafish embryos (2 h postfertilization, hpf) were exposed to different concentrations of the commercial PBDE mixture DE-71 (0-100 µg l-1 ) until 120 hpf, and the impact on neural development and serotonergic system was investigated. The in vivo results revealed significantly reduced transcription of genes involved in neurogenesis (fgf8, shha, wnt1), and contents of proteins in neuronal morphogenesis (myelin basic protein, synapsin IIa), suggesting an impairment of neural development in zebrafish embryos. Further results demonstrated a reduction of 5-hydroxytryptamine neuron and a dose-dependent decrease of whole-body serotonin levels, as well as the transcription of genes involved in serotonergic synthesis (tph1, tph2, trhr) and neurotransmission (serta/b, htr1aa/b). In addition, we predicted possible targets of PBDEs by molecular docking, and the results indicated that PBDE congeners showed high binding affinities with fibroblast growth factor 8 other than SHH and HTR1B. Taken together, this study demonstrated that PBDE exposure during embryogenesis could damage neural development and cause impairment of the serotonergic system as secondary effects in the zebrafish larvae. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Xianfeng Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Lihua Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| | - Qiangwei Wang
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, China
| | - Yongyong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Na Li
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Mei Ma
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
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Abstract
In the nervous system, axons transmit information in the form of electrical impulses over long distances. The speed of impulse conduction is enhanced by myelin, a lipid-rich membrane that wraps around axons. Myelin also is required for the long-term health of axons by providing metabolic support. Accordingly, myelin deficiencies are implicated in a wide range of neurodevelopmental and neuropsychiatric disorders, intellectual disabilities, and neurodegenerative conditions. Central nervous system myelin is formed by glial cells called oligodendrocytes. During development, oligodendrocyte precursor cells migrate from their origins to their target axons, extend long membrane processes that wrap axons, and produce the proteins and lipids that provide myelin membrane with its unique characteristics. Myelination is a dynamic process that involves intricate interactions between multiple cell types. Therefore, an in vivo myelination model, such as the zebrafish, which allows for live observation of cell dynamics and cell-to-cell interactions, is well suited for investigating oligodendrocyte development. Zebrafish offer several advantages to investigating myelination, including the use of transgenic reporter lines, live imaging, forward genetic screens, chemical screens, and reverse genetic approaches. This chapter will describe how these tools and approaches have provided new insights into the regulatory mechanisms that guide myelination.
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Affiliation(s)
- E S Mathews
- University of Colorado School of Medicine, Aurora, CO, United States
| | - B Appel
- University of Colorado School of Medicine, Aurora, CO, United States
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123
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Möbius W, Nave KA, Werner HB. Electron microscopy of myelin: Structure preservation by high-pressure freezing. Brain Res 2016; 1641:92-100. [PMID: 26920467 DOI: 10.1016/j.brainres.2016.02.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 02/16/2016] [Indexed: 10/24/2022]
Abstract
Electron microscopic visualization of nervous tissue morphology is crucial when aiming to understand the biogenesis and structure of myelin in healthy and pathological conditions. However, accurate interpretation of electron micrographs requires excellent tissue preservation. In this short review we discuss the recent utilization of tissue fixation by high-pressure freezing and freeze-substitution, which now supplements aldehyde fixation in the preparation of samples for electron microscopy of myelin. Cryofixation has proven well suited to yield both, improved contrast and excellent preservation of structural detail of the axon/myelin-unit in healthy and mutant mice and can also be applied to other model organisms, including aquatic species. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, 37075 Göttingen, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
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Abstract
UNLABELLED An important characteristic of vertebrate CNS development is the formation of specific amounts of insulating myelin membrane on axons. CNS myelin is produced by oligodendrocytes, glial cells that extend multiple membrane processes to wrap multiple axons. Recent data have shown that signaling mediated by the mechanistic target of rapamycin (mTOR) serine/threonine kinase promotes myelination, but factors that regulate mTOR activity for myelination remain poorly defined. Through a forward genetic screen in zebrafish, we discovered that mutation of fbxw7, which encodes the substrate recognition subunit of a SCF ubiquitin ligase that targets proteins for degradation, causes hypermyelination. Among known Fbxw7 targets is mTOR. Here, we provide evidence that mTOR signaling activity is elevated in oligodendrocyte lineage cells of fbxw7 mutant zebrafish larvae. Both genetic and pharmacological inhibition of mTOR function suppressed the excess myelin gene expression resulting from loss of Fbxw7 function, indicating that mTOR is a functionally relevant target of Fbxw7 in oligodendrocytes. fbxw7 mutant larvae wrapped axons with more myelin membrane than wild-type larvae and oligodendrocyte-specific expression of dominant-negative Fbxw7 produced longer myelin sheaths. Our data indicate that Fbxw7 limits the myelin-promoting activity of mTOR, thereby serving as an important brake on developmental myelination. SIGNIFICANCE STATEMENT Myelin, a specialized, proteolipid-rich membrane that ensheaths and insulates nerve fibers, facilitates the rapid conduction of electrical impulses over long distances. Abnormalities in myelin formation or maintenance result in intellectual and motor disabilities, raising a need for therapeutic strategies designed to promote myelination. The mTOR kinase is a powerful driver of myelination, but the mechanisms that regulate mTOR function in myelination are not well understood. Our studies reveal that Fbxw7, a subunit of a ubiquitin ligase that targets other proteins for degradation, acts as a brake on myelination by limiting mTOR function. These findings suggest that Fbxw7 helps tune the amount of myelin produced during development and raise the possibility that Fbxw7 could be a target of myelin-promoting therapies.
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125
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Transcriptome Analysis of Chemically-Induced Sensory Neuron Ablation in Zebrafish. PLoS One 2016; 11:e0148726. [PMID: 26863206 PMCID: PMC4749159 DOI: 10.1371/journal.pone.0148726] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/22/2016] [Indexed: 12/31/2022] Open
Abstract
Peripheral glia are known to have a critical role in the initial response to axon damage and degeneration. However, little is known about the cellular responses of non-myelinating glia to nerve injury. In this study, we analyzed the transcriptomes of wild-type and mutant (lacking peripheral glia) zebrafish larvae that were treated with metronidazole. This treatment allowed us to conditionally and selectively ablate cranial sensory neurons whose axons are ensheathed only by non-myelinating glia. While transcripts representing over 27,000 genes were detected by RNAseq, only a small fraction (~1% of genes) were found to be differentially expressed in response to neuronal degeneration in either line at either 2 hrs or 5 hrs of metronidazole treatment. Analysis revealed that most expression changes (332 out of the total of 458 differentially expressed genes) occurred over a continuous period (from 2 to 5 hrs of metronidazole exposure), with a small number of genes showing changes limited to only the 2 hr (55 genes) or 5 hr (71 genes) time points. For genes with continuous alterations in expression, some of the most meaningful sets of enriched categories in the wild-type line were those involving the inflammatory TNF-alpha and IL6 signaling pathways, oxidoreductase activities and response to stress. Intriguingly, these changes were not observed in the mutant line. Indeed, cluster analysis indicated that the effects of metronidazole treatment on gene expression was heavily influenced by the presence or absence of glia, indicating that the peripheral non-myelinating glia play a significant role in the transcriptional response to sensory neuron degeneration. This is the first transcriptome study of metronidazole-induced neuronal death in zebrafish and the response of non-myelinating glia to sensory neuron degeneration. We believe this study provides important insight into the mechanisms by which non-myelinating glia react to neuronal death and degeneration in sensory circuits.
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Radomska KJ, Sager J, Farnsworth B, Tellgren-Roth Å, Tuveri G, Peuckert C, Kettunen P, Jazin E, Emilsson LS. Characterization and Expression of the Zebrafish qki Paralogs. PLoS One 2016; 11:e0146155. [PMID: 26727370 PMCID: PMC4699748 DOI: 10.1371/journal.pone.0146155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 12/13/2015] [Indexed: 11/21/2022] Open
Abstract
Quaking (QKI) is an RNA-binding protein involved in post-transcriptional mRNA processing. This gene is found to be associated with several human neurological disorders. Early expression of QKI proteins in the developing mouse neuroepithelium, together with neural tube defects in Qk mouse mutants, suggest the functional requirement of Qk for the establishment of the nervous system. As a knockout of Qk is embryonic lethal in mice, other model systems like the zebrafish could serve as a tool to study the developmental functions of qki. In the present study we sought to characterize the evolutionary relationship and spatiotemporal expression of qkia, qki2, and qkib; zebrafish homologs of human QKI. We found that qkia is an ancestral paralog of the single tetrapod Qk gene that was likely lost during the fin-to-limb transition. Conversely, qkib and qki2 are orthologs, emerging at the root of the vertebrate and teleost lineage, respectively. Both qki2 and qkib, but not qkia, were expressed in the progenitor domains of the central nervous system, similar to expression of the single gene in mice. Despite having partially overlapping expression domains, each gene has a unique expression pattern, suggesting that these genes have undergone subfunctionalization following duplication. Therefore, we suggest the zebrafish could be used to study the separate functions of qki genes during embryonic development.
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Affiliation(s)
- Katarzyna J. Radomska
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Jonathan Sager
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Bryn Farnsworth
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Åsa Tellgren-Roth
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Giulia Tuveri
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Christiane Peuckert
- Department of Neuroscience, Uppsala Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Petronella Kettunen
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Neuropathology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Elena Jazin
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Lina S. Emilsson
- Department of Evolution and Development, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- * E-mail:
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The Autotaxin-Lysophosphatidic Acid Axis Modulates Histone Acetylation and Gene Expression during Oligodendrocyte Differentiation. J Neurosci 2015; 35:11399-414. [PMID: 26269646 DOI: 10.1523/jneurosci.0345-15.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED During development, oligodendrocytes (OLGs), the myelinating cells of the CNS, undergo a stepwise progression during which OLG progenitors, specified from neural stem/progenitor cells, differentiate into fully mature myelinating OLGs. This progression along the OLG lineage is characterized by well synchronized changes in morphology and gene expression patterns. The latter have been found to be particularly critical during the early stages of the lineage, and they have been well described to be regulated by epigenetic mechanisms, especially by the activity of the histone deacetylases HDAC1 and HDAC2. The data presented here identify the extracellular factor autotaxin (ATX) as a novel upstream signal modulating HDAC1/2 activity and gene expression in cells of the OLG lineage. Using the zebrafish as an in vivo model system as well as rodent primary OLG cultures, this functional property of ATX was found to be mediated by its lysophospholipase D (lysoPLD) activity, which has been well characterized to generate the lipid signaling molecule lysophosphatidic acid (LPA). More specifically, the lysoPLD activity of ATX was found to modulate HDAC1/2 regulated gene expression during a time window coinciding with the transition from OLG progenitor to early differentiating OLG. In contrast, HDAC1/2 regulated gene expression during the transition from neural stem/progenitor to OLG progenitor appeared unaffected by ATX and its lysoPLD activity. Thus, together, our data suggest that an ATX-LPA-HDAC1/2 axis regulates OLG differentiation specifically during the transition from OLG progenitor to early differentiating OLG and via a molecular mechanism that is evolutionarily conserved from at least zebrafish to rodent. SIGNIFICANCE STATEMENT The formation of the axon insulating and supporting myelin sheath by differentiating oligodendrocytes (OLGs) in the CNS is considered an essential step during vertebrate development. In addition, loss and/or dysfunction of the myelin sheath has been associated with a variety of neurologic diseases in which repair is limited, despite the presence of progenitor cells with the potential to differentiate into myelinating OLGs. This study characterizes the autotaxin-lysophosphatidic acid signaling axis as a modulator of OLG differentiation in vivo in the developing zebrafish and in vitro in rodent OLGs in culture. These findings provide novel insight into the regulation of developmental myelination, and they are likely to lead to advancing studies related to the stimulation of myelin repair under pathologic conditions.
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Stednitz SJ, Freshner B, Shelton S, Shen T, Black D, Gahtan E. Selective toxicity of L-DOPA to dopamine transporter-expressing neurons and locomotor behavior in zebrafish larvae. Neurotoxicol Teratol 2015; 52:51-6. [PMID: 26546233 DOI: 10.1016/j.ntt.2015.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 10/20/2015] [Accepted: 11/01/2015] [Indexed: 01/03/2023]
Abstract
Dopamine signaling is conserved across all animal species and has been implicated in the disease process of many neurological disorders, including Parkinson's disease (PD). The primary neuropathology in PD involves the death of dopaminergic cells in the substantia nigra (SN), an anatomical region of the brain implicated in dopamine production and voluntary motor control. Increasing evidence suggests that the neurotransmitter dopamine may have a neurotoxic metabolic product (DOPAL) that selectively damages dopaminergic cells. This study was designed to test this theory of oxidative damage in an animal model of Parkinson's disease, using a transgenic strain of zebrafish with fluorescent labeling of cells that express the dopamine transporter. The pretectum and ventral diencephalon exhibited reductions in cell numbers due to L-DOPA treatment while reticulospinal neurons that do not express the DAT were unaffected, and this was partially rescued by monoamine oxidase inhibition. Consistent with the MPTP model of PD in zebrafish larvae, spontaneous locomotor behavior in L-DOPA treated animals was depressed following a 24-h recovery period, while visually-evoked startle response rates and latencies were unaffected.
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Affiliation(s)
- Sarah J Stednitz
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States; University of Oregon, Eugene, Institute of Neuroscience, United States
| | - Briana Freshner
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States
| | - Samantha Shelton
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States; University of Massachusetts, Boston, Department of Neuroscience, United States
| | - Tori Shen
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States; University of California, San Diego, Eating Disorders Center for Treatment & Research, United States
| | - Donovan Black
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States
| | - Ethan Gahtan
- Department of Psychology, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, United States.
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The scales and tales of myelination: using zebrafish and mouse to study myelinating glia. Brain Res 2015; 1641:79-91. [PMID: 26498880 DOI: 10.1016/j.brainres.2015.10.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/06/2023]
Abstract
Myelin, the lipid-rich sheath that insulates axons to facilitate rapid conduction of action potentials, is an evolutionary innovation of the jawed-vertebrate lineage. Research efforts aimed at understanding the molecular mechanisms governing myelination have primarily focused on rodent models; however, with the advent of the zebrafish model system in the late twentieth century, the use of this genetically tractable, yet simpler vertebrate for studying myelination has steadily increased. In this review, we compare myelinating glial cell biology during development and regeneration in zebrafish and mouse and enumerate the advantages and disadvantages of using each model to study myelination. This article is part of a Special Issue entitled SI: Myelin Evolution.
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130
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Czopka T. Insights into mechanisms of central nervous system myelination using zebrafish. Glia 2015; 64:333-49. [PMID: 26250418 DOI: 10.1002/glia.22897] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 12/12/2022]
Abstract
Myelin is the multi-layered membrane that surrounds most axons and is produced by oligodendrocytes in the central nervous system (CNS). In addition to its important role in enabling rapid nerve conduction, it has become clear in recent years that myelin plays additional vital roles in CNS function. Myelinating oligodendrocytes provide metabolic support to axons and active myelination is even involved in regulating forms of learning and memory formation. However, there are still large gaps in our understanding of how myelination by oligodendrocytes is regulated. The small tropical zebrafish has become an increasingly popular model organism to investigate many aspects of nervous system formation, function, and regeneration. This is mainly due to two approaches for which the zebrafish is an ideally suited vertebrate model--(1) in vivo live cell imaging using vital dyes and genetically encoded reporters, and (2) gene and target discovery using unbiased screens. This review summarizes how the use of zebrafish has helped understand mechanisms of oligodendrocyte behavior and myelination in vivo and discusses the potential use of zebrafish to shed light on important future questions relating to myelination in the context of CNS development, function and repair.
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Affiliation(s)
- Tim Czopka
- Institute of Neuronal Cell Biology, Technische Universität München, Munich, Germany
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131
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Decrease in levels of the evolutionarily conserved microRNA miR-124 affects oligodendrocyte numbers in Zebrafish, Danio rerio. INVERTEBRATE NEUROSCIENCE 2015; 15:4. [PMID: 26159098 DOI: 10.1007/s10158-015-0180-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/29/2015] [Indexed: 01/08/2023]
Abstract
Oligodendrocytes produce multi-lamellar myelin membranes that surround axons in the central nervous system (CNS). Preservation and generation of myelin are potential therapeutic targets for dysmyelinating and demyelinating diseases. MicroRNAs (miRNAs) play a vital role in oligodendrocyte differentiation and overall CNS development. miR-124 is a well-conserved neuronal miRNA with important roles in neuronal differentiation and function. miR-124 levels increase following loss of myelin in both human and rodent brains. While the role of neuronal miR-124 in neurogenesis has been established, its effects on axonal outgrowth and oligodendrocytes are not currently known. We therefore explored the possible effect of selective knockdown of miR-124 in Danio rerio using a morpholino-based knockdown approach. No morphological abnormalities or loss of motor neurons were detected despite loss of axonal outgrowth. Morpholino-based knockdown of miR-124 led to reciprocal increases in mRNA levels of target genes that inhibit axonal and dendritic projections. Importantly, loss of miR-124 led to decreased oligodendrocyte cell numbers and myelination of axonal projections in the ventral hindbrain. Taken together, our results add a new dimension to the existing complexity of neuron-glial relationships and highlight the utility of Danio rerio as a model system to investigate such interactions.
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132
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Yang ML, Shin J, Kearns CA, Langworthy MM, Snell H, Walker MB, Appel B. CNS myelination requires cytoplasmic dynein function. Dev Dyn 2015; 244:134-45. [PMID: 25488883 DOI: 10.1002/dvdy.24238] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/26/2014] [Accepted: 12/03/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Cytoplasmic dynein provides the main motor force for minus-end-directed transport of cargo on microtubules. Within the vertebrate central nervous system (CNS), proliferation, neuronal migration, and retrograde axon transport are among the cellular functions known to require dynein. Accordingly, mutations of DYNC1H1, which encodes the heavy chain subunit of cytoplasmic dynein, have been linked to developmental brain malformations and axonal pathologies. Oligodendrocytes, the myelinating glial cell type of the CNS, migrate from their origins to their target axons and subsequently extend multiple long processes that ensheath axons with specialized insulating membrane. These processes are filled with microtubules, which facilitate molecular transport of myelin components. However, whether oligodendrocytes require cytoplasmic dynein to ensheath axons with myelin is not known. RESULTS We identified a mutation of zebrafish dync1h1 in a forward genetic screen that caused a deficit of oligodendrocytes. Using in vivo imaging and gene expression analyses, we additionally found evidence that dync1h1 promotes axon ensheathment and myelin gene expression. CONCLUSIONS In addition to its well known roles in axon transport and neuronal migration, cytoplasmic dynein contributes to neural development by promoting myelination.
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133
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Vittori M, Motaln H, Turnšek TL. The study of glioma by xenotransplantation in zebrafish early life stages. J Histochem Cytochem 2015; 63:749-61. [PMID: 26109632 DOI: 10.1369/0022155415595670] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/19/2015] [Indexed: 12/31/2022] Open
Abstract
Zebrafish (Danio rerio) and their transparent embryos are becoming an increasingly popular tool for studying processes involved in tumor progression and in the search for novel tumor treatment approaches. The xenotransplantation of fluorescently labeled mammalian cancer cells into zebrafish embryos is an approach enabling relatively high-throughput in vivo analyses. The small size of the embryos as well as the relative simplicity of their manipulation and maintenance allow for large numbers of embryos to be processed efficiently in a short time and at low cost. Furthermore, the possibility of fluorescence microscopic imaging of tumor progression within zebrafish embryos and larvae holds unprecedented potential for the real-time visualization of these processes in vivo. This review presents the methodologies of xenotransplantation studies on zebrafish involving research on tumor invasion, proliferation, tumor-induced angiogenesis and screening for antitumor therapeutics. We further focus on the application of these zebrafish to the study of glioma; in particular, its most common and malignant form, glioblastoma.
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Affiliation(s)
- Miloš Vittori
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia (MV, HM, TLT)
| | - Helena Motaln
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia (MV, HM, TLT)
| | - Tamara Lah Turnšek
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia (MV, HM, TLT)
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134
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Guo P, Huang Z, Tao T, Chen X, Zhang W, Zhang Y, Lin C. Zebrafish as a model for studying the developmental neurotoxicity of propofol. J Appl Toxicol 2015; 35:1511-9. [DOI: 10.1002/jat.3183] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 04/19/2015] [Accepted: 04/28/2015] [Indexed: 12/30/2022]
Affiliation(s)
- Peipei Guo
- Department of Anesthesiology; Nanfang Hospital of Southern Medical University; Guangzhou Guangdong China
| | - Zhibin Huang
- Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Cell Biology, School of Basic Medical Sciences; Southern Medical University; Guangzhou Guangdong China
| | - Tao Tao
- Department of Anesthesiology; Nanfang Hospital of Southern Medical University; Guangzhou Guangdong China
| | - Xiaohui Chen
- Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Cell Biology, School of Basic Medical Sciences; Southern Medical University; Guangzhou Guangdong China
| | - Wenqing Zhang
- Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Cell Biology, School of Basic Medical Sciences; Southern Medical University; Guangzhou Guangdong China
| | - Yiyue Zhang
- Key Laboratory of Zebrafish Modeling and Drug Screening for Human Diseases of Guangdong Higher Education Institutes, Department of Cell Biology, School of Basic Medical Sciences; Southern Medical University; Guangzhou Guangdong China
| | - Chunshui Lin
- Department of Anesthesiology; Nanfang Hospital of Southern Medical University; Guangzhou Guangdong China
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135
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Wang Q, Lai NLS, Wang X, Guo Y, Lam PKS, Lam JCW, Zhou B. Bioconcentration and transfer of the organophorous flame retardant 1,3-dichloro-2-propyl phosphate causes thyroid endocrine disruption and developmental neurotoxicity in zebrafish larvae. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:5123-32. [PMID: 25826601 DOI: 10.1021/acs.est.5b00558] [Citation(s) in RCA: 188] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Organophosphate flame retardants are emerging environmental contaminants, although knowledge of their health risks is limited. Here, thyroid hormone homeostasis and neuronal development was studied in the progeny of adult zebrafish exposed to tris(1,3-dichloro-2-propyl) phosphate (TDCPP). Adult zebrafish were exposed to TDCPP (0, 4, 20, and 100 μg/L) for 3 months. Increased generation of reactive oxygen species and reduced survival rates was observed in exposed F1 larvae. We also observed a significant decrease in plasma thyroxine and 3,5,3'-triiodothyronine levels in F0 females and F1 eggs/larvae. The mRNA and protein expression of factors associated with neuronal development (e.g., α1-tubulin, myelin basic protein, and synapsin IIa) were significantly downregulated in exposed F1 larvae, as was the level of the neurotransmitters dopamine, serotonin, gamma amino butyric acid, and histamine. Larval locomotion was significantly decreased in exposed fish, but there was no effect on acetylcholinesterase activity. Bioconcentration of TDCPP was observed in F0 fish. TDCPP was also detected in F1 eggs following parental exposure, indicating maternal transfer of this compound. This study uniquely shows that TDCPP can be transferred to the offspring of exposed adults, causing thyroid endocrine disruption and developmental neurotoxicity.
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Affiliation(s)
- Qiangwei Wang
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
- ‡University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nelson Lok-Shun Lai
- §State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
- ⊥Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Xianfeng Wang
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
- ‡University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongyong Guo
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Paul Kwan-Sing Lam
- §State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
- ⊥Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - James Chung-Wah Lam
- ∥Research Centre for the Oceans and Human Health, Shenzhen Key Laboratory for Sustainable Use of Marine Biodiversity, City University of Hong Kong Shenzhen Research Institute Building, Shenzhen, Guangdong 518057, China
| | - Bingsheng Zhou
- †State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
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Lutte AH, Capiotti KM, da Silva NLG, da Silva CSDO, Kist LW, Bogo MR, Da Silva RS. Contributions from extracellular sources of adenosine to the ethanol toxicity in zebrafish larvae. Reprod Toxicol 2015; 53:82-91. [PMID: 25883026 DOI: 10.1016/j.reprotox.2015.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/13/2015] [Accepted: 04/03/2015] [Indexed: 12/21/2022]
Abstract
The effects of ethanol exposure on extracellular adenosine sources in zebrafish were evaluated. In the acute treatment, the embryos were exposed to 2% ethanol on day 1 post-fertilization (dpf). In the chronic treatment, the exposure was continued for 2h/day up to 6 dpf. Ecto-5'-nucleotidase activity was assessed by colorimetric method and gene expression determined by RT-qPCR in 7 dpf zebrafish. Body length, ocular distance and surface area of the eyes were registered in animals acutely exposed to ethanol and pretreated with AOPCP (5-500 nM), an ecto-5'-nucleotidase inhibitor, or dipyridamole (10-100 μM), a blocker of nucleoside transport. Both ethanol exposures promoted increased ecto-5'-nucleotidase activity, impaired locomotion and morphology. Ecto-5'-nucleotidase expression was not affected. AOPCP promoted mild prevention of morphological defects caused by acute treatment, while dipyridamole worsened these defects. Early ethanol exposure altered adenosinergic tonus, especially through nucleoside transporters, contributing to morphological defects produced by ethanol in zebrafish.
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Affiliation(s)
- Aline Haab Lutte
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Katiucia Marques Capiotti
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Nicole Luize Garcia da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carolina Silveira de Oliveira da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Luiza Wilges Kist
- Laboratório de Biologia Genômica e Molecular, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil
| | - Maurício Reis Bogo
- Laboratório de Biologia Genômica e Molecular, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), 90035-003, Porto Alegre, RS, Brazil
| | - Rosane Souza Da Silva
- Laboratório de Neuroquímica e Psicofarmacologia, Departamento de Biologia Celular e Molecular, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil; Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), 90035-003, Porto Alegre, RS, Brazil.
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137
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The evolution of vertebrate and invertebrate myelin: a theoretical computational study. J Comput Neurosci 2015; 38:521-38. [PMID: 25832903 DOI: 10.1007/s10827-015-0552-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 02/20/2015] [Accepted: 03/04/2015] [Indexed: 01/11/2023]
Abstract
Multilayered, lipid-rich myelin increases nerve impulse conduction velocity, contributes to compact nervous systems, and reduces metabolic costs of neural activity. Based on the hypothesis that increased impulse conduction velocity provides a selective advantage that drives the evolution of myelin, we simulated a sequence of plausible intermediate stages of myelin evolution, each of which providing an enhancement of conduction speed. We started with the expansion of insulating glial coverage, which led first to a single layer of myelin surrounding the axon and then to multiple myelin wraps with well-organized nodes. The myelinated fiber was modeled at three levels of complexity as the hypothesized evolutionary progression became more quantitatively exacting: 1) representing the fiber as a mathematically-tractable uniform active cylinder with the effect of myelination approximated by changing its specific capacitance (C(m)); 2) representing it as a chain of simple, cable-model compartments having alternating nodal and internodal parameters subject to optimization, and 3) representing it in a double cable model with the axon and myelin sheath treated separately. Conduction velocity was optimized at each stage. To maintain optimal conduction velocities, increased myelin coverage of axonal surface must be accompanied by an increase in channel density at the evolving nodes, but along with increases in myelin thickness, a reduction in overall average channel density must occur. Leakage under the myelin sheath becomes more of a problem with smaller fiber diameters, which may help explain the tendency for myelin to occur preferentially in larger nerve fibers in both vertebrates and invertebrates.
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138
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Jin Y, Liu Z, Peng T, Fu Z. The toxicity of chlorpyrifos on the early life stage of zebrafish: a survey on the endpoints at development, locomotor behavior, oxidative stress and immunotoxicity. FISH & SHELLFISH IMMUNOLOGY 2015; 43:405-14. [PMID: 25634256 DOI: 10.1016/j.fsi.2015.01.010] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 01/10/2015] [Accepted: 01/19/2015] [Indexed: 05/15/2023]
Abstract
Chlorpyrifos (CPF) is one of the most toxic pesticides in aquatic ecosystem, but its toxicity mechanisms to fish are still not fully understood. This study examined the toxicity targets of CPF in early life stage of zebrafish on the endpoints at developmental toxicity, neurotoxicity, oxidative stress and immunotoxicity. Firstly, CPF exposure decreased the body length, inhibited the hatchability and heart rate, and resulted in a number of morphological abnormalities, primarily spinal deformities (SD) and pericardial edema (PE), in larval zebrafish. Secondly, the free swimming activities and the swimming behaviors of the larvae in response to the stimulation of light-to-dark photoperiod transition were significantly influenced by the exposure to 100 and 300 μg/L CPF. In addition, the activity of acetylcholinesterase (AChE) and the transcription of some genes related to neurotoxicity were also influenced by CPF exposure. Thirdly, CPF exposure induced oxidative stress in the larval zebrafish. The malondialdehyde (MDA) levels increased and the glutathione (GSH) contents decreased significantly in a concentration-dependent manner after the exposure to CPF for 96 hours post fertilization (hpf). CPF affected not only the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione S-transferase (GST), but also the transcriptional levels of their respective genes. Finally, the mRNA levels of the main cytokines including tumor necrosis factor α (Tnfα), interferon (Ifn), interleukin-1 beta (Il-1β), interleukin 6 (Il6), complement factor 4 (C4) in the larvae increased significantly after the exposure to 100 or 300 μg/L CPF for 96 hpf, suggesting that the innate immune system disturbed by CPF in larvae. Taken together, our results suggested that CPF had the potential to cause developmental toxicity, behavior alterations, oxidative stress and immunotoxicity in the larval zebrafish.
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Affiliation(s)
- Yuanxiang Jin
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhenzhen Liu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Tao Peng
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhengwei Fu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
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139
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Miao W, Zhu B, Xiao X, Li Y, Dirbaba NB, Zhou B, Wu H. Effects of titanium dioxide nanoparticles on lead bioconcentration and toxicity on thyroid endocrine system and neuronal development in zebrafish larvae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 161:117-126. [PMID: 25703175 DOI: 10.1016/j.aquatox.2015.02.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 06/04/2023]
Abstract
Nanoparticles (NPs) have attracted considerable attention because of their wide range of applications. Interactions between heavy metals (e.g., Pb) and NPs in aquatic environments may modify the bioavailability and toxicity of heavy metals. Therefore, this study investigated the influence of NPs (e.g., nano-TiO2) on the bioavailability and toxicity of Pb and its effects in the thyroid endocrine and nervous systems of zebrafish (Danio rerio) larvae. Zebrafish embryos (2-h post-fertilization) were exposed to five concentrations of Pb alone (0, 5, 10, 20, and 30μg/L) or in combination with nano-TiO2 (0.1mg/L) until 6 days post-fertilization. Results showed that the bioconcentration of Pb was significantly enhanced when combined with nano-TiO2 than when used alone. Zebrafish exposure to Pb alone at 30μg/L significantly decreased the thyroid hormone levels (T4 and T3), whereas nano-TiO2 treatment alone did not produce detectable changes. The levels of T4 and T3 were further decreased when Pb was combined with nano-TiO2 than when used alone. The transcription of the thyroid hormone-related factor tg gene was remarkably down-regulated by Pb treatment alone but up-regulated when Pb was combined with nano-TiO2. The significant up-regulation of tshβ gene and the down-regulation of TTR gene expression in the hypothalamic-pituitary-thyroid were observed in Pb with or without nano-TiO2 treatment groups. In addition, the transcription of genes involved in central nervous system (CNS) development (α-tubulin, mbp, gfap and shha) were significantly down-regulated by Pb and nano-TiO2 co-exposure as compared with Pb exposure alone. The locomotion activity analyzes confirmed that nano-TiO2 might enhance the toxicity of Pb to CNS development. These results suggest that nano-TiO2 increase bioconcentration of lead, which lead to the disruption of thyroid endocrine and neuronal system in zebrafish larvae.
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Affiliation(s)
- Wei Miao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Biran Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China
| | - Xiaohong Xiao
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Ying Li
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Niguse Bekele Dirbaba
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Hongjuan Wu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
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140
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Xiao Y, Faucherre A, Pola-Morell L, Heddleston JM, Liu TL, Chew TL, Sato F, Sehara-Fujisawa A, Kawakami K, López-Schier H. High-resolution live imaging reveals axon-glia interactions during peripheral nerve injury and repair in zebrafish. Dis Model Mech 2015; 8:553-64. [PMID: 26035865 PMCID: PMC4457030 DOI: 10.1242/dmm.018184] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 03/24/2015] [Indexed: 12/22/2022] Open
Abstract
Neural damage is a devastating outcome of physical trauma. The glia are one of the main effectors of neuronal repair in the nervous system, but the dynamic interactions between peripheral neurons and Schwann cells during injury and regeneration remain incompletely characterized. Here, we combine laser microsurgery, genetic analysis, high-resolution intravital imaging and lattice light-sheet microscopy to study the interaction between Schwann cells and sensory neurons in a zebrafish model of neurotrauma. We found that chronic denervation by neuronal ablation leads to Schwann-cell death, whereas acute denervation by axonal severing does not affect the overall complexity and architecture of the glia. Neuronal-circuit regeneration begins when Schwann cells extend bridging processes to close the injury gap. Regenerating axons grow faster and directionally after the physiological clearing of distal debris by the Schwann cells. This might facilitate circuit repair by ensuring that axons are guided through unoccupied spaces within bands of Büngner towards their original peripheral target. Accordingly, in the absence of Schwann cells, regenerating axons are misrouted, impairing the re-innervation of sensory organs. Our results indicate that regenerating axons use haptotaxis as a directional cue during the reconstitution of a neural circuit. These findings have implications for therapies aimed at neurorepair, which will benefit from preserving the architecture of the peripheral glia during periods of denervation. Summary: Schwann cells are important components of the peripheral glia. We use microsurgery and high-resolution live imaging to show how Schwann cells control the regeneration of a sensorineural circuit.
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Affiliation(s)
- Yan Xiao
- Research Unit Sensory Biology & Organogenesis, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Adèle Faucherre
- Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
| | - Laura Pola-Morell
- Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
| | - John M Heddleston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Tsung-Li Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Teng-Leong Chew
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Fuminori Sato
- Institute for Frontier Medical Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Atsuko Sehara-Fujisawa
- Institute for Frontier Medical Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, The Graduate University for Advanced Studies (Sokendai), 1111 Yata, Mishima, Shizuoka 411-8540, Japan Department of Genetics, The Graduate University for Advanced Studies (Sokendai), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Hernán López-Schier
- Research Unit Sensory Biology & Organogenesis, Helmholtz Zentrum München, 85764 Munich, Germany Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
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141
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Nishimura Y, Murakami S, Ashikawa Y, Sasagawa S, Umemoto N, Shimada Y, Tanaka T. Zebrafish as a systems toxicology model for developmental neurotoxicity testing. Congenit Anom (Kyoto) 2015; 55:1-16. [PMID: 25109898 DOI: 10.1111/cga.12079] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/29/2014] [Indexed: 12/18/2022]
Abstract
The developing brain is extremely sensitive to many chemicals. Exposure to neurotoxicants during development has been implicated in various neuropsychiatric and neurological disorders, including autism spectrum disorder, attention deficit hyperactive disorder, schizophrenia, Parkinson's disease, and Alzheimer's disease. Although rodents have been widely used for developmental neurotoxicity testing, experiments using large numbers of rodents are time-consuming, expensive, and raise ethical concerns. Using alternative non-mammalian animal models may relieve some of these pressures by allowing testing of large numbers of subjects while reducing expenses and minimizing the use of mammalian subjects. In this review, we discuss some of the advantages of using zebrafish in developmental neurotoxicity testing, focusing on central nervous system development, neurobehavior, toxicokinetics, and toxicodynamics in this species. We also describe some important examples of developmental neurotoxicity testing using zebrafish combined with gene expression profiling, neuroimaging, or neurobehavioral assessment. Zebrafish may be a systems toxicology model that has the potential to reveal the pathways of developmental neurotoxicity and to provide a sound basis for human risk assessments.
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Affiliation(s)
- Yuhei Nishimura
- Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Tsu, Japan; Mie University Medical Zebrafish Research Center, Tsu, Japan; Depertment of Systems Pharmacology, Mie University Graduate School of Medicine, Tsu, Japan; Department of Omics Medicine, Mie University Industrial Technology Innovation Institute, Tsu, Japan; Department of Bioinformatics, Mie University Life Science Research Center, Tsu, Japan
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143
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Wang Q, Lam JCW, Man YC, Lai NLS, Kwok KY, Guo YY, Lam PKS, Zhou B. Bioconcentration, metabolism and neurotoxicity of the organophorous flame retardant 1,3-dichloro 2-propyl phosphate (TDCPP) to zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 158:108-15. [PMID: 25461749 DOI: 10.1016/j.aquatox.2014.11.001] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/23/2014] [Accepted: 11/01/2014] [Indexed: 05/04/2023]
Abstract
Organophosphate flame retardants are ubiquitous environmental contaminants; however, knowledge is limited regarding their environmental health risks and toxicity. Here, we investigated the effects of acute and long-term exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) to the nervous system of zebrafish. Zebrafish embryos (2 h post-fertilization) were exposed to TDCPP (0-100 μg/L) for 6 months up until sexual maturation. Concentrations of TDCPP and its metabolic product (bis(1,3-dichloro-2-propyl) phosphate, BDCPP) were measured in the tissues of 5 day post-fertilization (dpf) larvae. There was no effect on locomotion, acetylcholinesterase activity, levels of the neurotransmitters dopamine and serotonin, and expression of mRNAs and proteins related to central nervous system development (e.g., myelin basic protein, α1-tubulin) in any exposure group. However, in adult fish, reductions of dopamine and serotonin levels were detected in the brains of females but not males. Downregulation of nervous system development genes was observed in both the male and female brain tissues. TDCPP concentrations were measured in adult fish tissues including the brain, and greater levels were detected in females. Our results showed that females are more sensitive to TDCPP stress than males in terms of TDCPP-induced neurotoxicity. We demonstrate that long-term exposure to lower concentrations of TDCPP in fish can lead to neurotoxicity.
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Affiliation(s)
- Qiangwei Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - James Chung-Wah Lam
- State Key Laboratory in Marine Pollution; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yin-Chung Man
- State Key Laboratory in Marine Pollution; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Nelson Lok-Shun Lai
- State Key Laboratory in Marine Pollution; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Karen Ying Kwok
- State Key Laboratory in Marine Pollution; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yong yong Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Paul Kwan-Sing Lam
- State Key Laboratory in Marine Pollution; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Research Centre for the Oceans and Human Health, City University of Hong Kong, Shenzhen Research Institute Building, Shenzhen 518057, China; Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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144
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Fang Y, Lei X, Li X, Chen Y, Xu F, Feng X, Wei S, Li Y. A novel model of demyelination and remyelination in a GFP-transgenic zebrafish. Biol Open 2014; 4:62-8. [PMID: 25527642 PMCID: PMC4295166 DOI: 10.1242/bio.201410736] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Demyelinating diseases consist of a variety of autoimmune conditions in which the myelin sheath is damaged due to genetic and/or environmental factors. During clinical treatment, some patients undergo partial remyelination, especially during the early disease stages. However, the mechanisms that regulate demyelination remain unclear. The myelin structure, myelin formation and myelin-related gene expression are highly conserved between mammals and zebrafish. Therefore, the zebrafish is an ideal model organism to study myelination. In this study, we generated a transgenic zebrafish Tg(mbp:nfsB-egfp) expressing a fusion protein composed of enhanced green fluorescent protein (EGFP) and NTR from the myelin basic protein (mbp) promoter. Tg(mbp:nfsB-egfp) expressed NTR-EGFP reproducibly and hereditarily in oligodendrocytes along the spinal cord. Treatment of zebrafish larvae Tg(mbp:nfsB-egfp) with metronidazole (Mtz) resulted in the selective ablation of oligodendrocytes and led to demyelination, accompanied by behavioral changes, including decreased total movement distance, velocity, total movement time and fast movement time. After withdrawal of Mtz for a seven day recovery period, the expression of EGFP and MBP protein was observed again which indicates remyelination. Additionally, locomotor capacity was restored. Collectively, Tg(mbp:nfsB-egfp), a heritable and stable transgenic line, provides a novel, powerful tool to study the mechanisms of demyelination and remyelination.
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Affiliation(s)
- Yangwu Fang
- Key Laboratory of Tumor Microenviroment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Xudan Lei
- Key Laboratory of Tumor Microenviroment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Xiang Li
- State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin 300071, China
| | - Yanan Chen
- Key Laboratory of Tumor Microenviroment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Fei Xu
- Key Laboratory of Tumor Microenviroment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
| | - Xizeng Feng
- State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin 300071, China
| | - Shihui Wei
- Department of Ophthalmology, Chinese PLA General Hospital, Beijing 100853, China
| | - Yuhao Li
- Key Laboratory of Tumor Microenviroment and Neurovascular Regulation, Nankai University School of Medicine, Tianjin 300071, China
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145
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Parichy DM, Spiewak JE. Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution. Pigment Cell Melanoma Res 2014; 28:31-50. [PMID: 25421288 DOI: 10.1111/pcmr.12332] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/20/2014] [Indexed: 12/25/2022]
Abstract
Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage, and mate choice and have played important roles in speciation. Here, we review studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve-associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns.
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Affiliation(s)
- David M Parichy
- Department of Biology, University of Washington, Seattle, WA, USA
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146
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Abstract
The zebrafish is a premier vertebrate model system that offers many experimental advantages for in vivo imaging and genetic studies. This review provides an overview of glial cell types in the central and peripheral nervous system of zebrafish. We highlight some recent work that exploited the strengths of the zebrafish system to increase the understanding of the role of Gpr126 in Schwann cell myelination and illuminate the mechanisms controlling oligodendrocyte development and myelination. We also summarize similarities and differences between zebrafish radial glia and mammalian astrocytes and consider the possibility that their distinct characteristics may represent extremes in a continuum of cell identity. Finally, we focus on the emergence of zebrafish as a model for elucidating the development and function of microglia. These recent studies have highlighted the power of the zebrafish system for analyzing important aspects of glial development and function.
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Affiliation(s)
- David A Lyons
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, California 94305
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147
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Blasky AJ, Pan L, Moens CB, Appel B. Pard3 regulates contact between neural crest cells and the timing of Schwann cell differentiation but is not essential for neural crest migration or myelination. Dev Dyn 2014; 243:1511-23. [PMID: 25130183 DOI: 10.1002/dvdy.24172] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Schwann cells, which arise from the neural crest, are the myelinating glia of the peripheral nervous system. During development neural crest and their Schwann cell derivatives engage in a sequence of events that comprise delamination from the neuroepithelium, directed migration, axon ensheathment, and myelin membrane synthesis. At each step neural crest and Schwann cells are polarized, suggesting important roles for molecules that create cellular asymmetries. In this work we investigated the possibility that one polarity protein, Pard3, contributes to the polarized features of neural crest and Schwann cells that are associated with directed migration and myelination. RESULTS We analyzed mutant zebrafish embryos deficient for maternal and zygotic pard3 function. Time-lapse imaging revealed that neural crest delamination was normal but that migrating cells were disorganized with substantial amounts of overlapping membrane. Nevertheless, neural crest cells migrated to appropriate peripheral targets. Schwann cells wrapped motor axons and, although myelin gene expression was delayed, myelination proceeded to completion. CONCLUSIONS Pard3 mediates contact inhibition between neural crest cells and promotes timely myelin gene expression but is not essential for neural crest migration or myelination.
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Affiliation(s)
- Alex J Blasky
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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148
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Zada D, Tovin A, Lerer-Goldshtein T, Vatine GD, Appelbaum L. Altered behavioral performance and live imaging of circuit-specific neural deficiencies in a zebrafish model for psychomotor retardation. PLoS Genet 2014; 10:e1004615. [PMID: 25255244 PMCID: PMC4177677 DOI: 10.1371/journal.pgen.1004615] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 07/18/2014] [Indexed: 11/28/2022] Open
Abstract
The mechanisms and treatment of psychomotor retardation, which includes motor and cognitive impairment, are indefinite. The Allan-Herndon-Dudley syndrome (AHDS) is an X-linked psychomotor retardation characterized by delayed development, severe intellectual disability, muscle hypotonia, and spastic paraplegia, in combination with disturbed thyroid hormone (TH) parameters. AHDS has been associated with mutations in the monocarboxylate transporter 8 (mct8/slc16a2) gene, which is a TH transporter. In order to determine the pathophysiological mechanisms of AHDS, MCT8 knockout mice were intensively studied. Although these mice faithfully replicated the abnormal serum TH levels, they failed to exhibit the neurological and behavioral symptoms of AHDS patients. Here, we generated an mct8 mutant (mct8−/−) zebrafish using zinc-finger nuclease (ZFN)-mediated targeted gene editing system. The elimination of MCT8 decreased the expression levels of TH receptors; however, it did not affect the expression of other TH-related genes. Similar to human patients, mct8−/− larvae exhibited neurological and behavioral deficiencies. High-throughput behavioral assays demonstrated that mct8−/− larvae exhibited reduced locomotor activity, altered response to external light and dark transitions and an increase in sleep time. These deficiencies in behavioral performance were associated with altered expression of myelin-related genes and neuron-specific deficiencies in circuit formation. Time-lapse imaging of single-axon arbors and synapses in live mct8−/− larvae revealed a reduction in filopodia dynamics and axon branching in sensory neurons and decreased synaptic density in motor neurons. These phenotypes enable assessment of the therapeutic potential of three TH analogs that can enter the cells in the absence of MCT8. The TH analogs restored the myelin and axon outgrowth deficiencies in mct8−/− larvae. These findings suggest a mechanism by which MCT8 regulates neural circuit assembly, ultimately mediating sensory and motor control of behavioral performance. We also propose that the administration of TH analogs early during embryo development can specifically reduce neurological damage in AHDS patients. In a wide range of brain disorders, mutations in specific genes cause alterations in the development and function of neural circuits that ultimately affect behavior. A major challenge is to uncover the mechanism and provide treatment which is capable of preventing brain damage. Allan-Herndon-Dudley syndrome (AHDS) is a severe psychomotor retardation characterized by intellectual disabilities, neurological impairment and abnormal thyroid hormone (TH) levels. Mutations in the TH transporter MCT8 are associated with AHDS. Mice that lack the MCT8 protein exhibited impaired TH levels, as is the case in human patients; however, they lack neurological defects. Here, we generated an mct8 mutant (mct8−/−) zebrafish, which exhibited neurological and behavioral deficiencies and mimics pathological conditions of AHDS patients. The zebrafish is a simple transparent vertebrate and its nervous system is conserved with mammals. Time-lapse live imaging of single axons and synapses, and video-tracking of behavior revealed deficiencies in neural circuit assembly, which are associated with disturbed sleep and altered locomotor activity. In addition, since the mct8−/− larvae provides a highthroughput platform for testing therapeutic drugs, we showed that TH analogs can recover neurological deficiencies in an animal model for psychomotor retardation.
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Affiliation(s)
- David Zada
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Adi Tovin
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Tali Lerer-Goldshtein
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Gad David Vatine
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Lior Appelbaum
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
- * E-mail:
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149
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Bai Q, Parris RS, Burton EA. Different mechanisms regulate expression of zebrafish myelin protein zero (P0) in myelinating oligodendrocytes and its induction following axonal injury. J Biol Chem 2014; 289:24114-28. [PMID: 25028515 DOI: 10.1074/jbc.m113.545426] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Zebrafish CNS axons regenerate robustly following injury; it is thought that CNS oligodendrocytes contribute to this response by expressing growth-promoting molecules. We characterized the mpz gene, which encodes myelin protein zero and is up-regulated in oligodendroglia following axonal injury. The 2.5-kb mpz mRNA is expressed from a single TATA box promoter. Four independent Tg(mpz:egfp) transgenic zebrafish lines, in which GFP was expressed under the mpz promoter and 10 kb of genomic 5'-flanking sequence, showed transgene expression in CNS oligodendrocytes from larval development through adulthood. Following optic nerve crush injury, the mpz:egfp transgene was strongly up-regulated in oligodendrocytes along the regenerating retinotectal projection, mirroring up-regulation of endogenous mpz mRNA. GFP-expressing oligodendroglia were significantly more abundant in the regenerating optic pathway, resulting from both transgene induction in oligodendroglial precursors and the birth of new cells. Up-regulation of the mpz:egfp transgene was not dependent on axonal regeneration, suggesting that the primary signal may be axonal loss, debris, or microglial infiltration. Deletion experiments indicated that an oligodendroglial enhancer located in the region from -6 to -10 kb with respect to the mpz transcriptional start site is dissociable from the cis-regulatory element mediating the mpz transcriptional response to axonal injury, which is located between -1 and -4 kb. These data show that different mechanisms regulate expression of zebrafish mpz in myelinating oligodendrocytes and its induction following axonal injury. The underlying molecular events could potentially be exploited to enhance axonal repair following mammalian CNS injury. The transgenic lines and cis-regulatory constructs reported here will facilitate identification of the relevant signaling pathways.
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Affiliation(s)
- Qing Bai
- From the Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, and
| | - Ritika S Parris
- From the Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, and
| | - Edward A Burton
- From the Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, and Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 and the Geriatric Research Education and Clinical Center and Department of Neurology, Pittsburgh Veterans Affairs Healthcare System, Pittsburgh, Pennsylvania 15240
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150
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Sirisi S, Folgueira M, López-Hernández T, Minieri L, Pérez-Rius C, Gaitán-Peñas H, Zang J, Martínez A, Capdevila-Nortes X, De La Villa P, Roy U, Alia A, Neuhauss S, Ferroni S, Nunes V, Estévez R, Barrallo-Gimeno A. Megalencephalic leukoencephalopathy with subcortical cysts protein 1 regulates glial surface localization of GLIALCAM from fish to humans. Hum Mol Genet 2014; 23:5069-86. [DOI: 10.1093/hmg/ddu231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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