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Banerjee S, Szyszka P, Beck CW. Knockdown of NeuroD2 leads to seizure-like behavior, brain neuronal hyperactivity and a leaky blood-brain barrier in a Xenopus laevis tadpole model of DEE75. Genetics 2024; 227:iyae085. [PMID: 38788202 PMCID: PMC11228833 DOI: 10.1093/genetics/iyae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 04/18/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Developmental and Epileptic Encephalopathies (DEE) are a genetically diverse group of severe, early onset seizure disorders. DEE are normally identified clinically in the first six months of life by the presence of frequent, difficult to control seizures and accompanying stalling or regression of development. DEE75 results from de novo mutations of the NEUROD2 gene that result in loss of activity of the encoded transcription factor, and the seizure phenotype was shown to be recapitulated in Xenopus tropicalis tadpoles. We used CRISPR/Cas9 to make a DEE75 model in Xenopus laevis, to further investigate the developmental etiology. NeuroD2.S CRISPR/Cas9 edited tadpoles were more active, swam faster on average, and had more seizures (C-shaped contractions resembling unprovoked C-start escape responses) than their sibling controls. Live imaging of Ca2+ signaling revealed prolongued, strong signals sweeping through the brain, indicative of neuronal hyperactivity. While the resulting tadpole brain appeared grossly normal, the blood-brain barrier (BBB) was found to be leakier than that of controls. Additionally, the TGFβ antagonist Losartan was shown to have a short-term protective effect, reducing neuronal hyperactivity and reducing permeability of the BBB. Treatment of NeuroD2 CRISPant tadpoles with 5 mM Losartan decreased seizure events by more than 4-fold compared to the baseline. Our results support a model of DEE75 resulting from reduced NeuroD2 activity during vertebrate brain development, and indicate that a leaky BBB contributes to epileptogenesis.
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Affiliation(s)
- Sulagna Banerjee
- Department of Zoology, University of Otago, PO Box56, Dunedin 9016, New Zealand
| | - Paul Szyszka
- Department of Zoology, University of Otago, PO Box56, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
| | - Caroline W Beck
- Department of Zoology, University of Otago, PO Box56, Dunedin 9016, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
- Genetics Otago Research Centre, University of Otago, Dunedin 9016, New Zealand
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2
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Park J, Lee E, Kim CH, Ohk J, Jung H. Mosaicism-independent mechanisms contribute to Pcdh19-related epilepsy and repetitive behaviors in Xenopus. Proc Natl Acad Sci U S A 2024; 121:e2321388121. [PMID: 38748583 PMCID: PMC11126968 DOI: 10.1073/pnas.2321388121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 04/05/2024] [Indexed: 05/27/2024] Open
Abstract
Protocadherin19 (PCDH19)-related epilepsy syndrome is a rare disorder characterized by early-onset epilepsy, intellectual disability, and autistic behaviors. PCDH19 is located on the X chromosome and encodes a calcium-dependent single-pass transmembrane protein, which regulates cell-to-cell adhesion through homophilic binding. In human, 90% of heterozygous females, containing PCDH19 wild-type and mutant cells due to random X inactivation, are affected, whereas mutant males, containing only mutant cells, are typically not. The current view, the cellular interference, is that the altered interactions between wild-type and mutant cells during development, rather than loss of function itself, are responsible. However, studies using Pcdh19 knockout mice showed that the complete loss of function also causes autism-like behaviors both in males and females, suggesting that other functions of PCDH19 may also contribute to pathogenesis. To address whether mosaicism is required for PCDH19-related epilepsy, we generated Xenopus tropicalis tadpoles with complete or mosaic loss of function by injecting antisense morpholino oligonucleotides into the blastomeres of neural lineage at different stages of development. We found that either mosaic or complete knockdown results in seizure-like behaviors, which could be rescued by antiseizure medication, and repetitive behaviors. Our results suggest that the loss of PCDH19 function itself, in addition to cellular interference, may also contribute to PCDH19-related epilepsy.
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Affiliation(s)
- Jugeon Park
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul03722, Republic of Korea
| | - Eunee Lee
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul03722, Republic of Korea
| | - Chul Hoon Kim
- Department of Pharmacology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul03722, Republic of Korea
| | - Jiyeon Ohk
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul03722, Republic of Korea
| | - Hosung Jung
- Department of Anatomy, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul03722, Republic of Korea
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3
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Bullard MR, Cervantes JCM, Quaicoe NB, Jin A, Adams DA, Lin JM, Iliadis E, Seidler TM, Cervantes-Sandoval I, He HY. Accelerated protein retention expansion microscopy using microwave radiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.593228. [PMID: 38766072 PMCID: PMC11100821 DOI: 10.1101/2024.05.11.593228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Protein retention expansion microscopy (ExM) retains genetically encoded fluorescent proteins or antibody-conjugated fluorescent probes in fixed tissue and isotropically expands the tissue through a swellable polymer network to allow nanoscale (<70 nm) resolution on diffraction-limited confocal microscopes. Despite numerous advantages ExM brings to biological studies, the full protocol is time-consuming and can take multiple days to complete. Here, we adapted the ExM protocol to the vibratome-sectioned brain tissue of Xenopus laevis tadpoles and implemented a microwave-assisted protocol to reduce the workflow from days to hours. In addition to the significantly accelerated processing time, our microwave-assisted ExM (M/WExM) protocol maintains the superior resolution and signal-to-noise ratio of the original ExM protocol. Furthermore, the M/WExM protocol yields higher magnitude of expansion, suggesting that in addition to accelerating the process through increased diffusion rate of reagents, microwave radiation may also facilitate the expansion process. To demonstrate the applicability of this method to other specimens and protocols, we adapted the microwave-accelerated protocol to whole mount adult brain tissue of Drosophila melanogaster fruit flies, and successfully reduced the total processing time of a widely-used Drosophila IHC-ExM protocol from 6 days to 2 days. Our results demonstrate that with appropriate adjustment of the microwave parameters (wattage, pulse duration, interval, and number of cycles), this protocol can be readily adapted to different model organisms and tissue types to greatly increase the efficiency of ExM experiments.
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Affiliation(s)
| | | | | | - Amanda Jin
- Department of Biology, Georgetown University, Washington, DC 20057
| | - Danya A. Adams
- Department of Biology, Georgetown University, Washington, DC 20057
| | - Jessica M. Lin
- Department of Biology, Georgetown University, Washington, DC 20057
| | - Elena Iliadis
- Department of Biology, Georgetown University, Washington, DC 20057
| | - Tess M. Seidler
- Department of Biology, Georgetown University, Washington, DC 20057
| | | | - Hai-yan He
- Department of Biology, Georgetown University, Washington, DC 20057
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4
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Metruccio F, Battistoni M, Di Renzo F, Bacchetta R, Santo N, Menegola E. Teratogenic and neuro-behavioural toxic effects of bisphenol A (BPA) and B (BPB) on Xenopus laevis development. Reprod Toxicol 2024; 123:108496. [PMID: 37951421 DOI: 10.1016/j.reprotox.2023.108496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 10/05/2023] [Accepted: 11/02/2023] [Indexed: 11/14/2023]
Abstract
Bisphenol A (BPA) is a plastic additive with endocrine disruptive activity, classified in 2017 by EU ECHA as substance of very high concern. A correlation between environmental exposure to BPA and congenital defects has been described in humans and in experimental species, including the amphibian Xenopus laevis. Among BPA analogues, bisphenol B (BPB) is used as alternative in different not-EU countries, including US, but seems to share with BPA its endocrine disruptor properties. Aim of the present work is the evaluation of the effects of BPB versus BPA exposure in a X. laevis developmental model. A windowed exposure (R-FETAX method) was applied covering the developmental phylotypic period (teratogenicity window), or the late tailbud stages (neuro-behavioural toxicity window, corresponding to the spontaneous swimming acquisition period). Samples were monitored for lethal effects during the full test period. External morphology evaluation and deglutition functional test were applied in any group. Abnormal tadpoles were also processed for cartilage staining. In groups exposed during neuro-behavioural toxicity window the swimming test was also applied. Lethality and malformations were obtained only in samples exposed during the teratogenicity window; these data were modelled using PROAST software and BPB relative potency resulted about 3 times higher than BPA. The day-by-day evaluation revealed that lethality was correlated to embryonic abnormal development of gills and apoptosis in gill primordia. Teratogenicity was never detected in groups exposed during the neuro-behavioural toxicity window, where some significant neuro-behavioural deficits were detected in tadpoles exposed to the highest tested concentrations of BPA and BPB.
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Affiliation(s)
- F Metruccio
- ICPS, ASST Fatebenefratelli Sacco, via GB Grassi, 74, 20159 Milan, Italy
| | - M Battistoni
- Department of Environmental Science and Policy, Università degli Studi di Milano, via Celoria, 26, 20133 Milan, Italy
| | - F Di Renzo
- Department of Environmental Science and Policy, Università degli Studi di Milano, via Celoria, 26, 20133 Milan, Italy.
| | - R Bacchetta
- Department of Environmental Science and Policy, Università degli Studi di Milano, via Celoria, 26, 20133 Milan, Italy
| | - N Santo
- Unitech NOLIMITS, Imaging Facility, Università degli Studi di Milano, via Golgi, 19, 20133 Milan, Italy
| | - E Menegola
- Department of Environmental Science and Policy, Università degli Studi di Milano, via Celoria, 26, 20133 Milan, Italy
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5
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Manicka S, Pai VP, Levin M. Information integration during bioelectric regulation of morphogenesis of the embryonic frog brain. iScience 2023; 26:108398. [PMID: 38034358 PMCID: PMC10687303 DOI: 10.1016/j.isci.2023.108398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 07/18/2023] [Accepted: 11/02/2023] [Indexed: 12/02/2023] Open
Abstract
Spatiotemporal patterns of cellular resting potential regulate several aspects of development. One key aspect of the bioelectric code is that transcriptional and morphogenetic states are determined not by local, single-cell, voltage levels but by specific distributions of voltage across cell sheets. We constructed and analyzed a minimal dynamical model of collective gene expression in cells based on inputs of multicellular voltage patterns. Causal integration analysis revealed a higher-order mechanism by which information about the voltage pattern was spatiotemporally integrated into gene activity, as well as a division of labor among and between the bioelectric and genetic components. We tested and confirmed predictions of this model in a system in which bioelectric control of morphogenesis regulates gene expression and organogenesis: the embryonic brain of the frog Xenopus laevis. This study demonstrates that machine learning and computational integration approaches can advance our understanding of the information-processing underlying morphogenetic decision-making, with a potential for other applications in developmental biology and regenerative medicine.
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Affiliation(s)
- Santosh Manicka
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Vaibhav P. Pai
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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6
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Neuronal membrane proteasomes regulate neuronal circuit activity in vivo and are required for learning-induced behavioral plasticity. Proc Natl Acad Sci U S A 2023; 120:e2216537120. [PMID: 36630455 PMCID: PMC9934054 DOI: 10.1073/pnas.2216537120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Protein degradation is critical for brain function through processes that remain incompletely understood. Here, we investigated the in vivo function of the 20S neuronal membrane proteasome (NMP) in the brain of Xenopus laevis tadpoles. With biochemistry, immunohistochemistry, and electron microscopy, we demonstrated that NMPs are conserved in the tadpole brain and preferentially degrade neuronal activity-induced newly synthesized proteins in vivo. Using in vivo calcium imaging in the optic tectum, we showed that acute NMP inhibition rapidly increased spontaneous neuronal activity, resulting in hypersynchronization across tectal neurons. At the circuit level, inhibiting NMPs abolished learning-dependent improvement in visuomotor behavior in live animals and caused a significant deterioration in basal behavioral performance following visual training with enhanced visual experience. Our data provide in vivo characterization of NMP functions in the vertebrate nervous system and suggest that NMP-mediated degradation of activity-induced nascent proteins may serve as a homeostatic modulatory mechanism in neurons that is critical for regulating neuronal activity and experience-dependent circuit plasticity.
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7
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Gao J, Luo Y, Lu Y, Wu X, Chen P, Zhang X, Han L, Qiu M, Shen W. Epigenetic regulation of GABAergic differentiation in the developing brain. Front Cell Neurosci 2022; 16:988732. [PMID: 36212693 PMCID: PMC9539098 DOI: 10.3389/fncel.2022.988732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
In the vertebrate brain, GABAergic cell development and neurotransmission are important for the establishment of neural circuits. Various intrinsic and extrinsic factors have been identified to affect GABAergic neurogenesis. However, little is known about the epigenetic control of GABAergic differentiation in the developing brain. Here, we report that the number of GABAergic neurons dynamically changes during the early tectal development in the Xenopus brain. The percentage of GABAergic neurons is relatively unchanged during the early stages from stage 40 to 46 but significantly decreased from stage 46 to 48 tadpoles. Interestingly, the histone acetylation of H3K9 is developmentally decreased from stage 42 to 48 (about 3.5 days). Chronic application of valproate acid (VPA), a broad-spectrum histone deacetylase (HDAC) inhibitor, at stage 46 for 48 h increases the acetylation of H3K9 and the number of GABAergic cells in the optic tectum. VPA treatment also reduces apoptotic cells. Electrophysiological recordings show that a VPA induces an increase in the frequency of mIPSCs and no changes in the amplitude. Behavioral studies reveal that VPA decreases swimming activity and visually guided avoidance behavior. These findings extend our understanding of histone modification in the GABAergic differentiation and neurotransmission during early brain development.
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Affiliation(s)
- Juanmei Gao
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yuhao Luo
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yufang Lu
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xiaohua Wu
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Peiyao Chen
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xinyu Zhang
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Lu Han
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Mengsheng Qiu
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- *Correspondence: Mengsheng Qiu,
| | - Wanhua Shen
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Wanhua Shen,
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8
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Shen B, Pade LR, Choi SB, Muñoz-LLancao P, Manzini MC, Nemes P. Capillary Electrophoresis Mass Spectrometry for Scalable Single-Cell Proteomics. Front Chem 2022; 10:863979. [PMID: 35464213 PMCID: PMC9024316 DOI: 10.3389/fchem.2022.863979] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/28/2022] [Indexed: 12/11/2022] Open
Abstract
Understanding the biochemistry of the cell requires measurement of all the molecules it produces. Single-cell proteomics recently became possible through advances in microanalytical sample preparation, separation by nano-flow liquid chromatography (nanoLC) and capillary electrophoresis (CE), and detection using electrospray ionization (ESI) high-resolution mass spectrometry (HRMS). Here, we demonstrate capillary microsampling CE-ESI-HRMS to be scalable to proteomics across broad cellular dimensions. This study established proof-of-principle using giant, ∼250-µm-diameter cells from embryos of the frog Xenopus laevis and small, ∼35-µm-diameter neurons in culture from the mouse hippocampus. From ∼18 ng, or ∼0.2% of the total cellular proteome, subcellular analysis of the ventral-animal midline (V11) and equatorial (V12) cells identified 1,133 different proteins in a 16-cell embryo. CE-HRMS achieved ∼20-times higher sensitivity and doubled the speed of instrumental measurements compared to nanoLC, the closest neighboring single-cell technology of choice. Microanalysis was scalable to 722 proteins groups from ∼5 ng of cellular protein digest from identified left dorsal-animal midline cell (D11), supporting sensitivity for smaller cells. Capillary microsampling enabled the isolation and transfer of individual neurons from the culture, identifying 37 proteins between three different cells. A total of 224 proteins were detected from 500 pg of neuronal protein digest, which estimates to a single neuron. Serial dilution returned 157 proteins from sample amounts estimating to about half a cell (250 pg protein) and 70 proteins from ca. a quarter of a neuron (125 pg protein), suggesting sufficient sensitivity for subcellular proteomics. CE-ESI-HRMS complements nanoLC proteomics with scalability, sensitivity, and speed across broad cellular dimensions.
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Affiliation(s)
- Bowen Shen
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, United States
| | - Leena R. Pade
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, United States
| | - Sam B. Choi
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, United States
| | - Pablo Muñoz-LLancao
- Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, The State University of New Jersey, New Brunswick, NJ, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, United States
| | - M. Chiara Manzini
- Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States
- Department of Neuroscience and Cell Biology and Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, The State University of New Jersey, New Brunswick, NJ, United States
| | - Peter Nemes
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, United States
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9
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Caporale N, Leemans M, Birgersson L, Germain PL, Cheroni C, Borbély G, Engdahl E, Lindh C, Bressan RB, Cavallo F, Chorev NE, D'Agostino GA, Pollard SM, Rigoli MT, Tenderini E, Tobon AL, Trattaro S, Troglio F, Zanella M, Bergman Å, Damdimopoulou P, Jönsson M, Kiess W, Kitraki E, Kiviranta H, Nånberg E, Öberg M, Rantakokko P, Rudén C, Söder O, Bornehag CG, Demeneix B, Fini JB, Gennings C, Rüegg J, Sturve J, Testa G. From cohorts to molecules: Adverse impacts of endocrine disrupting mixtures. Science 2022; 375:eabe8244. [PMID: 35175820 DOI: 10.1126/science.abe8244] [Citation(s) in RCA: 113] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Convergent evidence associates exposure to endocrine disrupting chemicals (EDCs) with major human diseases, even at regulation-compliant concentrations. This might be because humans are exposed to EDC mixtures, whereas chemical regulation is based on a risk assessment of individual compounds. Here, we developed a mixture-centered risk assessment strategy that integrates epidemiological and experimental evidence. We identified that exposure to an EDC mixture in early pregnancy is associated with language delay in offspring. At human-relevant concentrations, this mixture disrupted hormone-regulated and disease-relevant regulatory networks in human brain organoids and in the model organisms Xenopus leavis and Danio rerio, as well as behavioral responses. Reinterrogating epidemiological data, we found that up to 54% of the children had prenatal exposures above experimentally derived levels of concern, reaching, for the upper decile compared with the lowest decile of exposure, a 3.3 times higher risk of language delay.
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Affiliation(s)
- Nicolò Caporale
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milan, 20122 Milan, Italy.,Human Technopole, V.le Rita Levi-Montalcini, 1, 20157 Milan, Italy
| | - Michelle Leemans
- UMR 7221, Phyma, CNRS-Muséum National d'Histoire Naturelle, Sorbonne Université, 75005 Paris, France
| | - Lina Birgersson
- Department of Biological and Environmental Sciences, University of Gothenburg, 41463 Gothenburg, Sweden
| | - Pierre-Luc Germain
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Cristina Cheroni
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milan, 20122 Milan, Italy.,Human Technopole, V.le Rita Levi-Montalcini, 1, 20157 Milan, Italy
| | - Gábor Borbély
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden
| | - Elin Engdahl
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden.,Department of Organismal Biology, Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Christian Lindh
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden
| | - Raul Bardini Bressan
- Medical Research Council Centre for Regenerative Medicine and Edinburgh Cancer Research UK Centre, University of Edinburgh, Edinburgh, UK
| | - Francesca Cavallo
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Nadav Even Chorev
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Giuseppe Alessandro D'Agostino
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Steven M Pollard
- Medical Research Council Centre for Regenerative Medicine and Edinburgh Cancer Research UK Centre, University of Edinburgh, Edinburgh, UK
| | - Marco Tullio Rigoli
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milan, 20122 Milan, Italy
| | - Erika Tenderini
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Alejandro Lopez Tobon
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Sebastiano Trattaro
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milan, 20122 Milan, Italy
| | - Flavia Troglio
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Matteo Zanella
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy
| | - Åke Bergman
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden.,Department of Environmental Science, Stockholm University, SE-10691 Stockholm, Sweden.,School of Science and Technology, Örebro University, SE-70182 Örebro, Sweden
| | - Pauliina Damdimopoulou
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden.,Division of Obstetrics and Gynecology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Maria Jönsson
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Wieland Kiess
- Hospital for Children and Adolescents, Department of Women and Child Health, University Hospital, University of Leipzig, 04103 Leipzig, Germany
| | - Efthymia Kitraki
- Lab of Basic Sciences, Faculty of Dentistry, National and Kapodistrian University of Athens, 152 72 Athens, Greece
| | - Hannu Kiviranta
- Department of Health Security, Finnish Institute for Health and Welfare (THL), Kuopio 70210, Finland
| | - Eewa Nånberg
- School of Health Sciences, Örebro University, SE-70182 Örebro, Sweden
| | - Mattias Öberg
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden.,Institute of Environmental Medicine, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Panu Rantakokko
- Department of Health Security, Finnish Institute for Health and Welfare (THL), Kuopio 70210, Finland
| | - Christina Rudén
- Department of Environmental Science, Stockholm University, SE-10691 Stockholm, Sweden
| | - Olle Söder
- Department of Women's and Children's Health, Pediatric Endocrinology Division, Karolinska Institutet and University Hospital, SE-17176 Stockholm, Sweden
| | - Carl-Gustaf Bornehag
- Faculty of Health, Science and Technology, Department of Health Sciences, Karlstad University, SE- 651 88 Karlstad, Sweden.,Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Barbara Demeneix
- UMR 7221, Phyma, CNRS-Muséum National d'Histoire Naturelle, Sorbonne Université, 75005 Paris, France
| | - Jean-Baptiste Fini
- UMR 7221, Phyma, CNRS-Muséum National d'Histoire Naturelle, Sorbonne Université, 75005 Paris, France
| | - Chris Gennings
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Joëlle Rüegg
- Swedish Toxicology Sciences Research Center (SWETOX), Södertälje, Sweden.,Department of Organismal Biology, Environmental Toxicology, Uppsala University, SE-752 36 Uppsala, Sweden
| | - Joachim Sturve
- Department of Biological and Environmental Sciences, University of Gothenburg, 41463 Gothenburg, Sweden
| | - Giuseppe Testa
- High Definition Disease Modelling Lab, Stem Cell and Organoid Epigenetics, IEO, European Institute of Oncology, IRCCS, 20141 Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milan, 20122 Milan, Italy.,Human Technopole, V.le Rita Levi-Montalcini, 1, 20157 Milan, Italy
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10
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Closset M, Cailliau K, Slaby S, Marin M. Effects of Aluminium Contamination on the Nervous System of Freshwater Aquatic Vertebrates: A Review. Int J Mol Sci 2021; 23:ijms23010031. [PMID: 35008450 PMCID: PMC8744726 DOI: 10.3390/ijms23010031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 12/18/2022] Open
Abstract
Aluminium (Al) is the most common natural metallic element in the Earth’s crust. It is released into the environment through natural processes and human activities and accumulates in aquatic environments. This review compiles scientific data on the neurotoxicity of aluminium contamination on the nervous system of aquatic organisms. More precisely, it helps identify biomarkers of aluminium exposure for aquatic environment biomonitoring in freshwater aquatic vertebrates. Al is neurotoxic and accumulates in the nervous system of aquatic vertebrates, which is why it could be responsible for oxidative stress. In addition, it activates and inhibits antioxidant enzymes and leads to changes in acetylcholinesterase activity, neurotransmitter levels, and in the expression of several neural genes and nerve cell components. It also causes histological changes in nerve tissue, modifications of organism behaviour, and cognitive deficit. However, impacts of aluminium exposure on the early stages of aquatic vertebrate development are poorly described. Lastly, this review also poses the question of how accurate aquatic vertebrates (fishes and amphibians) could be used as model organisms to complement biological data relating to the developmental aspect. This “challenge” is very relevant since freshwater pollution with heavy metals has increased in the last few decades.
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Affiliation(s)
- Marie Closset
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; (M.C.); (K.C.)
| | - Katia Cailliau
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; (M.C.); (K.C.)
| | - Sylvain Slaby
- Normandie University, UNILEHAVRE, CNRS, UMR 3730 SCALE, Environmental Stress and Aquatic Biomonitoring (SEBIO), F-76600 Le Havre, France;
| | - Matthieu Marin
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France; (M.C.); (K.C.)
- Correspondence:
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11
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Gore SV, James EJ, Huang LC, Park JJ, Berghella A, Thompson AC, Cline HT, Aizenman CD. Role of matrix metalloproteinase-9 in neurodevelopmental deficits and experience-dependent plasticity in Xenopus laevis. eLife 2021; 10:62147. [PMID: 34282726 PMCID: PMC8315794 DOI: 10.7554/elife.62147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 07/18/2021] [Indexed: 02/06/2023] Open
Abstract
Matrix metalloproteinase-9 (MMP-9) is a secreted endopeptidase targeting extracellular matrix proteins, creating permissive environments for neuronal development and plasticity. Developmental dysregulation of MMP-9 may also lead to neurodevelopmental disorders (ND). Here, we test the hypothesis that chronically elevated MMP-9 activity during early neurodevelopment is responsible for neural circuit hyperconnectivity observed in Xenopus tadpoles after early exposure to valproic acid (VPA), a known teratogen associated with ND in humans. In Xenopus tadpoles, VPA exposure results in excess local synaptic connectivity, disrupted social behavior and increased seizure susceptibility. We found that overexpressing MMP-9 in the brain copies effects of VPA on synaptic connectivity, and blocking MMP-9 activity pharmacologically or genetically reverses effects of VPA on physiology and behavior. We further show that during normal neurodevelopment MMP-9 levels are tightly regulated by neuronal activity and required for structural plasticity. These studies show a critical role for MMP-9 in both normal and abnormal development.
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Affiliation(s)
- Sayali V Gore
- Department of Neuroscience, Brown University, Providence, United States
| | - Eric J James
- Department of Neuroscience, Brown University, Providence, United States
| | | | - Jenn J Park
- Department of Neuroscience, Brown University, Providence, United States
| | - Andrea Berghella
- Department of Neuroscience, Brown University, Providence, United States
| | - Adrian C Thompson
- Department of Neuroscience, Brown University, Providence, United States
| | | | - Carlos D Aizenman
- Department of Neuroscience, Brown University, Providence, United States
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12
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Liu K, Garcia A, Park JJ, Toliver AA, Ramos L, Aizenman CD. Early Developmental Exposure to Fluoxetine and Citalopram Results in Different Neurodevelopmental Outcomes. Neuroscience 2021; 467:110-121. [PMID: 34048796 DOI: 10.1016/j.neuroscience.2021.05.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/25/2022]
Abstract
Although selective serotonin reuptake inhibitors are commonly prescribed for prenatal depression, there exists controversy over adverse effects of SSRI use on fetal development. Few studies have adequately isolated outcomes due to SSRI exposure and those due to maternal psychiatric conditions. Here, we directly investigated outcomes of exposure to widely-used SSRIs Fluoxetine and Citalopram on the developing nervous system of Xenopus laevis tadpoles, using an integrative experimental approach. We exposed tadpoles to low doses of Citalopram and Fluoxetine during a critical developmental period and found that different experimental groups displayed opposing behavioral effects. While both groups showed reduced schooling behavior, the Fluoxetine group showed increased seizure susceptibility and reduced startle habituation. In contrast, Citalopram treated tadpoles had decreased seizure susceptibility and increased habituation. Both groups had abnormal dendritic morphology in the optic tectum, a brain area important for behaviors tested. Whole-cell electrophysiological recordings of tectal neurons showed no differences in synaptic function; however, tectal cells from Fluoxetine-treated tadpoles had decreased voltage gated K+ currents while cells in the Citalopram group had increased K+ currents. Both behavioral and electrophysiological findings indicate that cells and circuits in the Fluoxetine treated optic tecta are hyperexcitable, while the Citalopram group exhibits decreased excitability. Taken together, these results show that early developmental exposure to SSRIs is sufficient to induce neurodevelopmental effects, however these effects can be complex and vary depending on the SSRI. This may explain some discrepancies across human studies, and further underscores the importance of serotonergic signaling for the developing nervous system.
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Affiliation(s)
- Karine Liu
- Department of Neuroscience, Brown University, United States
| | - Alfonso Garcia
- Department of Neuroscience, Brown University, United States
| | - Jenn J Park
- Department of Neuroscience, Brown University, United States
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13
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Baxi AB, Pade LR, Nemes P. Mass spectrometry based proteomics for developmental neurobiology in the amphibian Xenopus laevis. Curr Top Dev Biol 2021; 145:205-231. [PMID: 34074530 PMCID: PMC8314003 DOI: 10.1016/bs.ctdb.2021.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The South African clawed frog (Xenopus laevis), a prominent vertebrate model in cell and developmental biology, has been instrumental in studying molecular mechanisms of neural development and disease. Recently, high-resolution mass spectrometry (HRMS), a bioanalytical technology, has expanded the molecular toolbox of protein detection and characterization (proteomics). This chapter overviews the characteristics, advantages, and challenges of this biological model and technology. Discussions are offered on their combined use to aid studies on cell differentiation and development of neural tissues. Finally, the emerging integration of proteomics and other 'omic technologies is reflected on to generate new knowledge, drive and test new hypotheses, and ultimately, advance the understanding of neural development during states of health and disease.
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Affiliation(s)
- Aparna B Baxi
- Department of Chemistry & Biochemistry, University of Maryland, College Park, College Park, MD, United States; Department of Anatomy and Cell Biology, The George Washington University, Washington, DC, United States
| | - Leena R Pade
- Department of Chemistry & Biochemistry, University of Maryland, College Park, College Park, MD, United States
| | - Peter Nemes
- Department of Chemistry & Biochemistry, University of Maryland, College Park, College Park, MD, United States; Department of Anatomy and Cell Biology, The George Washington University, Washington, DC, United States.
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14
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Exner CRT, Willsey HR. Xenopus leads the way: Frogs as a pioneering model to understand the human brain. Genesis 2021; 59:e23405. [PMID: 33369095 PMCID: PMC8130472 DOI: 10.1002/dvg.23405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
From its long history in the field of embryology to its recent advances in genetics, Xenopus has been an indispensable model for understanding the human brain. Foundational studies that gave us our first insights into major embryonic patterning events serve as a crucial backdrop for newer avenues of investigation into organogenesis and organ function. The vast array of tools available in Xenopus laevis and Xenopus tropicalis allows interrogation of developmental phenomena at all levels, from the molecular to the behavioral, and the application of CRISPR technology has enabled the investigation of human disorder risk genes in a higher-throughput manner. As the only major tetrapod model in which all developmental stages are easily manipulated and observed, frogs provide the unique opportunity to study organ development from the earliest stages. All of these features make Xenopus a premier model for studying the development of the brain, a notoriously complex process that demands an understanding of all stages from fertilization to organogenesis and beyond. Importantly, core processes of brain development are conserved between Xenopus and human, underlining the advantages of this model. This review begins by summarizing discoveries made in amphibians that form the cornerstones of vertebrate neurodevelopmental biology and goes on to discuss recent advances that have catapulted our understanding of brain development in Xenopus and in relation to human development and disease. As we engage in a new era of patient-driven gene discovery, Xenopus offers exceptional potential to uncover conserved biology underlying human brain disorders and move towards rational drug design.
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Affiliation(s)
- Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
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15
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Walentek P. Xenopus epidermal and endodermal epithelia as models for mucociliary epithelial evolution, disease, and metaplasia. Genesis 2021; 59:e23406. [PMID: 33400364 DOI: 10.1002/dvg.23406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 11/08/2022]
Abstract
The Xenopus embryonic epidermis is a powerful model to study mucociliary biology, development, and disease. Particularly, the Xenopus system is being used to elucidate signaling pathways, transcription factor functions, and morphogenetic mechanisms regulating cell fate specification, differentiation and cell function. Thereby, Xenopus research has provided significant insights into potential underlying molecular mechanisms for ciliopathies and chronic airway diseases. Recent studies have also established the embryonic epidermis as a model for mucociliary epithelial remodeling, multiciliated cell trans-differentiation, cilia loss, and mucus secretion. Additionally, the tadpole foregut epithelium is lined by a mucociliary epithelium, which shows remarkable features resembling mammalian airway epithelia, including its endodermal origin and a variable cell type composition along the proximal-distal axis. This review aims to summarize the advantages of the Xenopus epidermis for mucociliary epithelial biology and disease modeling. Furthermore, the potential of the foregut epithelium as novel mucociliary model system is being highlighted. Additional perspectives are presented on how to expand the range of diseases that can be modeled in the frog system, including proton pump inhibitor-associated pneumonia as well as metaplasia in epithelial cells of the airway and the gastroesophageal region.
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Affiliation(s)
- Peter Walentek
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.,CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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16
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Gao J, Shen W. Xenopus in revealing developmental toxicity and modeling human diseases. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115809. [PMID: 33096388 DOI: 10.1016/j.envpol.2020.115809] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 10/01/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
The Xenopus model offers many advantages for investigation of the molecular, cellular, and behavioral mechanisms underlying embryo development. Moreover, Xenopus oocytes and embryos have been extensively used to study developmental toxicity and human diseases in response to various environmental chemicals. This review first summarizes recent advances in using Xenopus as a vertebrate model to study distinct types of tissue/organ development following exposure to environmental toxicants, chemical reagents, and pharmaceutical drugs. Then, the successful use of Xenopus as a model for diseases, including fetal alcohol spectrum disorders, autism, epilepsy, and cardiovascular disease, is reviewed. The potential application of Xenopus in genetic and chemical screening to protect against embryo deficits induced by chemical toxicants and related diseases is also discussed.
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Affiliation(s)
- Juanmei Gao
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China; College of Life and Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Wanhua Shen
- Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, 311121, China.
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17
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Schwenty-Lara J, Pauli S, Borchers A. Using Xenopus to analyze neurocristopathies like Kabuki syndrome. Genesis 2020; 59:e23404. [PMID: 33351273 DOI: 10.1002/dvg.23404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 11/08/2022]
Abstract
Neurocristopathies are human congenital syndromes that arise from defects in neural crest (NC) development and are typically associated with malformations of the craniofacial skeleton. Genetic analyses have been very successful in identifying pathogenic mutations, however, model organisms are required to characterize how these mutations affect embryonic development thereby leading to complex clinical conditions. The African clawed frog Xenopus laevis provides a broad range of in vivo and in vitro tools allowing for a detailed characterization of NC development. Due to the conserved nature of craniofacial morphogenesis in vertebrates, Xenopus is an efficient and versatile system to dissect the morphological and cellular phenotypes as well as the signaling events leading to NC defects. Here, we review a set of techniques and resources how Xenopus can be used as a disease model to investigate the pathogenesis of Kabuki syndrome and neurocristopathies in a wider sense.
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Affiliation(s)
- Janina Schwenty-Lara
- Department of Biology, Molecular Embryology, Philipps-University Marburg, Marburg, Germany
| | - Silke Pauli
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Annette Borchers
- Department of Biology, Molecular Embryology, Philipps-University Marburg, Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University Marburg, Marburg, Germany
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18
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Abboud C, Duveau A, Bouali-Benazzouz R, Massé K, Mattar J, Brochoire L, Fossat P, Boué-Grabot E, Hleihel W, Landry M. Animal models of pain: Diversity and benefits. J Neurosci Methods 2020; 348:108997. [PMID: 33188801 DOI: 10.1016/j.jneumeth.2020.108997] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 11/03/2020] [Accepted: 11/08/2020] [Indexed: 12/15/2022]
Abstract
Chronic pain is a maladaptive neurological disease that remains a major health problem. A deepening of our knowledge on mechanisms that cause pain is a prerequisite to developing novel treatments. A large variety of animal models of pain has been developed that recapitulate the diverse symptoms of different pain pathologies. These models reproduce different pain phenotypes and remain necessary to examine the multidimensional aspects of pain and understand the cellular and molecular basis underlying pain conditions. In this review, we propose an overview of animal models, from simple organisms to rodents and non-human primates and the specific traits of pain pathologies they model. We present the main behavioral tests for assessing pain and investing the underpinning mechanisms of chronic pathological pain. The validity of animal models is analysed based on their ability to mimic human clinical diseases and to predict treatment outcomes. Refine characterization of pathological phenotypes also requires to consider pain globally using specific procedures dedicated to study emotional comorbidities of pain. We discuss the limitations of pain models when research findings fail to be translated from animal models to human clinics. But we also point to some recent successes in analgesic drug development that highlight strategies for improving the predictive validity of animal models of pain. Finally, we emphasize the importance of using assortments of preclinical pain models to identify pain subtype mechanisms, and to foster the development of better analgesics.
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Affiliation(s)
- Cynthia Abboud
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France; Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France; Faculty of Arts and Sciences, Holy Spirit University of Kaslik (USEK), Lebanon
| | - Alexia Duveau
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Rabia Bouali-Benazzouz
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Karine Massé
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Joseph Mattar
- School of Medicine and Medical Sciences, Holy Spirit University of Kaslik (USEK), Lebanon
| | - Louison Brochoire
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Pascal Fossat
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Eric Boué-Grabot
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France
| | - Walid Hleihel
- School of Medicine and Medical Sciences, Holy Spirit University of Kaslik (USEK), Lebanon; Faculty of Arts and Sciences, Holy Spirit University of Kaslik (USEK), Lebanon
| | - Marc Landry
- Univ. Bordeaux, CNRS, Institute for Neurodegenerative Diseases, IMN, UMR 5293, F-33000 Bordeaux, France.
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19
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Pai VP, Cervera J, Mafe S, Willocq V, Lederer EK, Levin M. HCN2 Channel-Induced Rescue of Brain Teratogenesis via Local and Long-Range Bioelectric Repair. Front Cell Neurosci 2020; 14:136. [PMID: 32528251 PMCID: PMC7264377 DOI: 10.3389/fncel.2020.00136] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/22/2020] [Indexed: 12/21/2022] Open
Abstract
Embryonic exposure to the teratogen nicotine results in brain defects, by disrupting endogenous spatial pre patterns necessary for normal brain size and patterning. Extending prior work in Xenopus laevis that showed that misexpression of ion channels can rescue morphogenesis, we demonstrate and characterize a novel aspect of developmental bioelectricity: channel-dependent repair signals propagate long-range across the embryo. We show that distal HCN2 channel misexpression and distal transplants of HCN2-expressing tissue, non-cell-autonomously reverse profound defects, rescuing brain anatomy, gene expression, and learning. Moreover, such rescue can be induced by small-molecule HCN2 channel activators, even with delayed treatment initiation. We present a simple, versatile computational model of bioelectrical signaling upstream of key patterning genes such as OTX2 and XBF1, which predicts long-range repair induced by ion channel activity, and experimentally validate the predictions of this model. Our results and quantitative model identify a powerful morphogenetic control mechanism that could be targeted by future regenerative medicine exploiting ion channel modulating drugs approved for human use.
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Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Javier Cervera
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Salvador Mafe
- Departament de Termodinamica, Facultat de Fisica, Universitat de Valencia, Burjassot, Spain
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Emma K Lederer
- Allen Discovery Center at Tufts University, Medford, MA, United States
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, United States
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20
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Couderq S, Leemans M, Fini JB. Testing for thyroid hormone disruptors, a review of non-mammalian in vivo models. Mol Cell Endocrinol 2020; 508:110779. [PMID: 32147522 DOI: 10.1016/j.mce.2020.110779] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
Abstract
Thyroid hormones (THs) play critical roles in profound changes in many vertebrates, notably in mammalian neurodevelopment, although the precise molecular mechanisms of these fundamental biological processes are still being unravelled. Environmental and health concerns prompted the development of chemical safety testing and, in the context of endocrine disruption, identification of thyroid hormone axis disrupting chemicals (THADCs) remains particularly challenging. As various molecules are known to interfere with different levels of TH signalling, screening tests for THADCs may not rely solely on in vitro ligand/receptor binding to TH receptors. Therefore, alternatives to mammalian in vivo assays featuring TH-related endpoints that are more sensitive than circulatory THs and more rapid than thyroid histopathology are needed to fulfil the ambition of higher throughput screening of the myriad of environmental chemicals. After a detailed introduction of the context, we have listed current assays and parameters to assess thyroid disruption following a literature search of recent publications referring to non-mammalian models. Potential THADCs were mostly investigated in zebrafish and the frog Xenopus laevis, an amphibian model extensively used to study TH signalling.
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Affiliation(s)
- Stephan Couderq
- Unité PhyMA laboratory, Adaptation du Vivant, Muséum national d'Histoire naturelle, 7 rue Cuvier, 75005, Paris, France
| | - Michelle Leemans
- Unité PhyMA laboratory, Adaptation du Vivant, Muséum national d'Histoire naturelle, 7 rue Cuvier, 75005, Paris, France
| | - Jean-Baptiste Fini
- Unité PhyMA laboratory, Adaptation du Vivant, Muséum national d'Histoire naturelle, 7 rue Cuvier, 75005, Paris, France.
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21
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Singh MD, Jensen M, Lasser M, Huber E, Yusuff T, Pizzo L, Lifschutz B, Desai I, Kubina A, Yennawar S, Kim S, Iyer J, Rincon-Limas DE, Lowery LA, Girirajan S. NCBP2 modulates neurodevelopmental defects of the 3q29 deletion in Drosophila and Xenopus laevis models. PLoS Genet 2020; 16:e1008590. [PMID: 32053595 PMCID: PMC7043793 DOI: 10.1371/journal.pgen.1008590] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/26/2020] [Accepted: 12/30/2019] [Indexed: 12/12/2022] Open
Abstract
The 1.6 Mbp deletion on chromosome 3q29 is associated with a range of neurodevelopmental disorders, including schizophrenia, autism, microcephaly, and intellectual disability. Despite its importance towards neurodevelopment, the role of individual genes, genetic interactions, and disrupted biological mechanisms underlying the deletion have not been thoroughly characterized. Here, we used quantitative methods to assay Drosophila melanogaster and Xenopus laevis models with tissue-specific individual and pairwise knockdown of 14 homologs of genes within the 3q29 region. We identified developmental, cellular, and neuronal phenotypes for multiple homologs of 3q29 genes, potentially due to altered apoptosis and cell cycle mechanisms during development. Using the fly eye, we screened for 314 pairwise knockdowns of homologs of 3q29 genes and identified 44 interactions between pairs of homologs and 34 interactions with other neurodevelopmental genes. Interestingly, NCBP2 homologs in Drosophila (Cbp20) and X. laevis (ncbp2) enhanced the phenotypes of homologs of the other 3q29 genes, leading to significant increases in apoptosis that disrupted cellular organization and brain morphology. These cellular and neuronal defects were rescued with overexpression of the apoptosis inhibitors Diap1 and xiap in both models, suggesting that apoptosis is one of several potential biological mechanisms disrupted by the deletion. NCBP2 was also highly connected to other 3q29 genes in a human brain-specific interaction network, providing support for the relevance of our results towards the human deletion. Overall, our study suggests that NCBP2-mediated genetic interactions within the 3q29 region disrupt apoptosis and cell cycle mechanisms during development. Rare copy-number variants, or large deletions and duplications in the genome, are associated with a wide range of neurodevelopmental disorders. The 3q29 deletion confers an increased risk for schizophrenia and autism. To understand the conserved biological mechanisms that are disrupted by this deletion, we systematically tested 14 individual homologs and 314 pairwise interactions of 3q29 genes for neuronal, cellular, and developmental phenotypes in Drosophila melanogaster and Xenopus laevis models. We found that multiple homologs of genes within the deletion region contribute towards developmental defects, such as larval lethality and disrupted cellular organization. Interestingly, we found that NCBP2 acts as a key modifier gene within the region, enhancing the developmental phenotypes of each of the homologs for other 3q29 genes and leading to disruptions in apoptosis and cell cycle pathways. Our results suggest that multiple genes within the 3q29 region interact with each other through shared mechanisms and jointly contribute to neurodevelopmental defects.
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Affiliation(s)
- Mayanglambam Dhruba Singh
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew Jensen
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Emily Huber
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Tanzeen Yusuff
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lucilla Pizzo
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Brian Lifschutz
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Inshya Desai
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Alexis Kubina
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sneha Yennawar
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sydney Kim
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Janani Iyer
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
- Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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22
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Pai VP, Adams DS. Preventing Ethanol-Induced Brain and Eye Morphology Defects Using Optogenetics. Bioelectricity 2019; 1:260-272. [PMID: 32685918 DOI: 10.1089/bioe.2019.0008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Embryonic exposure to the teratogen ethanol leads to dysmorphias, including eye and brain morphology defects associated with fetal alcohol spectrum disorder (FASD). Exposure of Xenopus laevis embryos to ethanol leads to similar developmental defects, including brain and eye dysmorphism, confirming our work and the work of others showing Xenopus as a useful system for studies of the brain and eye birth defects associated with FASD. Several targets of ethanol action have been hypothesized, one being regulation of Kir2.1 potassium channel. Endogenous ion fluxes and membrane voltage variation (bioelectric signals) have been shown to be powerful regulators of embryonic cell behaviors that are required for correct brain and eye morphology. Disruptions to these voltage patterns lead to spatially correlated disruptions in gene expression patterns and corresponding morphology. Materials and Methods: Here, we use controlled membrane voltage modulation to determine when and where voltage modulation is sufficient to rescue ethanol-induced brain and eye defects in Xenopus embryos. Results: We found (1) that modulating membrane voltage using light activation of the channelrhodopsin-2 variant D156A rescues ethanol exposed embryos, resulting in normal brain and eye morphologies; (2) hyperpolarization is required for the full duration of ethanol exposure; (3) hyperpolarization of only superficial ectoderm is sufficient for this effect; and(4) the rescue effect acts at a distance. Conclusions: These results, particularly the last, raise the exciting possibility of using bioelectric modulation to treat ethanol-induced brain and eye birth defects, possibly with extant ion channel drugs already prescribed to pregnant women. This may prove to be a simple and cost-effective strategy for reducing the impact of FASD.
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Affiliation(s)
- Vaibhav P Pai
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts
| | - Dany Spencer Adams
- Department of Biology, Tufts University, Medford, Massachusetts.,Ion Diagnostics LLC, Watertown, Massachusetts
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23
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Toward Decoding Bioelectric Events in Xenopus Embryogenesis: New Methodology for Tracking Interplay Between Calcium and Resting Potentials In Vivo. J Mol Biol 2019; 432:605-620. [PMID: 31711960 DOI: 10.1016/j.jmb.2019.10.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 10/07/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
Although chemical signaling during embryogenesis is readily addressed by a plethora of available techniques, the developmental functions of ionic signaling are still poorly understood. It is increasingly realized that bioelectric events in nonneural cells are critical for pattern regulation, but their study has been hampered by difficulties in monitoring and manipulating them in vivo. Recent developments in visualizing electrical signaling dynamics in the field of neuroscience have facilitated functional experiments that reveal instructive developmental bioelectric signals. However, there is a pressing need for additional tools to explore time-dependent ionic signaling to understand complex endogenous dynamics. Here, we present methodological advances, including 4D imaging and data analysis, for improved tracking of calcium flux in the Xenopus laevis embryo, lowering the barrier for in vivo physiology work in this important model system. Using these techniques, we investigated the relationship between bioelectric ion channel activity and calcium, finding that cell hyperpolarization and depolarization both induce persistent static elevation of cytoplasmic calcium levels that fade over developmental time. These calcium changes correlate with increased cell mobility in early embryos and abnormal craniofacial morphology in later embryos. We thus highlight membrane potential modulation as a tractable tool for modulation of signaling cascades that rely on calcium as a transduction mechanism. The methods we describe facilitate the study of important novel aspects of developmental physiology, are extendable to numerous classes of existing and forthcoming fluorescent physiological reporters, and establish highly accessible, inexpensive protocols for their investigation.
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24
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Busch SE, Khakhalin AS. Intrinsic temporal tuning of neurons in the optic tectum is shaped by multisensory experience. J Neurophysiol 2019; 122:1084-1096. [PMID: 31291161 DOI: 10.1152/jn.00099.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For a biological neural network to be functional, its neurons need to be connected with synapses of appropriate strength, and each neuron needs to appropriately respond to its synaptic inputs. This second aspect of network tuning is maintained by intrinsic plasticity; yet it is often considered secondary to changes in connectivity and mostly limited to adjustments of overall excitability of each neuron. Here we argue that even nonoscillatory neurons can be tuned to inputs of different temporal dynamics and that they can routinely adjust this tuning to match the statistics of their synaptic activation. Using the dynamic clamp technique, we show that, in the tectum of Xenopus tadpole, neurons become selective for faster inputs when animals are exposed to fast visual stimuli but remain responsive to longer inputs in animals exposed to slower, looming, or multisensory stimulation. We also report a homeostatic cotuning between synaptic and intrinsic temporal properties of individual tectal cells. These results expand our understanding of intrinsic plasticity in the brain and suggest that there may exist an additional dimension of network tuning that has been so far overlooked.NEW & NOTEWORTHY We use dynamic clamp to show that individual neurons in the tectum of Xenopus tadpoles are selectively tuned to either shorter (more synchronous) or longer (less synchronous) synaptic inputs. We also demonstrate that this intrinsic temporal tuning is strongly shaped by sensory experiences. This new phenomenon, which is likely to be mediated by changes in sodium channel inactivation, is bound to have important consequences for signal processing and the development of local recurrent connections.
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Affiliation(s)
- Silas E Busch
- Biology Program, Bard College, Annandale-on-Hudson, New York
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25
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Lasser M, Pratt B, Monahan C, Kim SW, Lowery LA. The Many Faces of Xenopus: Xenopus laevis as a Model System to Study Wolf-Hirschhorn Syndrome. Front Physiol 2019; 10:817. [PMID: 31297068 PMCID: PMC6607408 DOI: 10.3389/fphys.2019.00817] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 06/11/2019] [Indexed: 01/09/2023] Open
Abstract
Wolf–Hirschhorn syndrome (WHS) is a rare developmental disorder characterized by intellectual disability and various physical malformations including craniofacial, skeletal, and cardiac defects. These phenotypes, as they involve structures that are derived from the cranial neural crest, suggest that WHS may be associated with abnormalities in neural crest cell (NCC) migration. This syndrome is linked with assorted mutations on the short arm of chromosome 4, most notably the microdeletion of a critical genomic region containing several candidate genes. However, the function of these genes during embryonic development, as well as the cellular and molecular mechanisms underlying the disorder, are still unknown. The model organism Xenopus laevis offers a number of advantages for studying WHS. With the Xenopus genome sequenced, genetic manipulation strategies can be readily designed in order to alter the dosage of the WHS candidate genes. Moreover, a variety of assays are available for use in Xenopus to examine how manipulation of WHS genes leads to changes in the development of tissue and organ systems affected in WHS. In this review article, we highlight the benefits of using X. laevis as a model system for studying human genetic disorders of development, with a focus on WHS.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Benjamin Pratt
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Connor Monahan
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Seung Woo Kim
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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26
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Nenni MJ, Fisher ME, James-Zorn C, Pells TJ, Ponferrada V, Chu S, Fortriede JD, Burns KA, Wang Y, Lotay VS, Wang DZ, Segerdell E, Chaturvedi P, Karimi K, Vize PD, Zorn AM. Xenbase: Facilitating the Use of Xenopus to Model Human Disease. Front Physiol 2019; 10:154. [PMID: 30863320 PMCID: PMC6399412 DOI: 10.3389/fphys.2019.00154] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 02/08/2019] [Indexed: 01/02/2023] Open
Abstract
At a fundamental level most genes, signaling pathways, biological functions and organ systems are highly conserved between man and all vertebrate species. Leveraging this conservation, researchers are increasingly using the experimental advantages of the amphibian Xenopus to model human disease. The online Xenopus resource, Xenbase, enables human disease modeling by curating the Xenopus literature published in PubMed and integrating these Xenopus data with orthologous human genes, anatomy, and more recently with links to the Online Mendelian Inheritance in Man resource (OMIM) and the Human Disease Ontology (DO). Here we review how Xenbase supports disease modeling and report on a meta-analysis of the published Xenopus research providing an overview of the different types of diseases being modeled in Xenopus and the variety of experimental approaches being used. Text mining of over 50,000 Xenopus research articles imported into Xenbase from PubMed identified approximately 1,000 putative disease- modeling articles. These articles were manually assessed and annotated with disease ontologies, which were then used to classify papers based on disease type. We found that Xenopus is being used to study a diverse array of disease with three main experimental approaches: cell-free egg extracts to study fundamental aspects of cellular and molecular biology, oocytes to study ion transport and channel physiology and embryo experiments focused on congenital diseases. We integrated these data into Xenbase Disease Pages to allow easy navigation to disease information on external databases. Results of this analysis will equip Xenopus researchers with a suite of experimental approaches available to model or dissect a pathological process. Ideally clinicians and basic researchers will use this information to foster collaborations necessary to interrogate the development and treatment of human diseases.
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Affiliation(s)
- Mardi J Nenni
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Malcolm E Fisher
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Christina James-Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Troy J Pells
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Virgilio Ponferrada
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Stanley Chu
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Joshua D Fortriede
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kevin A Burns
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Ying Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Vaneet S Lotay
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Dong Zhou Wang
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Erik Segerdell
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, United States
| | - Praneet Chaturvedi
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Kamran Karimi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Peter D Vize
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children's Hospital, Cincinnati, OH, United States
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27
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Batool S, Raza H, Zaidi J, Riaz S, Hasan S, Syed NI. Synapse formation: from cellular and molecular mechanisms to neurodevelopmental and neurodegenerative disorders. J Neurophysiol 2019; 121:1381-1397. [PMID: 30759043 DOI: 10.1152/jn.00833.2018] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The precise patterns of neuronal assembly during development determine all functional outputs of a nervous system; these may range from simple reflexes to learning, memory, cognition, etc. To understand how brain functions and how best to repair it after injury, disease, or trauma, it is imperative that we first seek to define fundamental steps mediating this neuronal assembly. To acquire the sophisticated ensemble of highly specialized networks seen in a mature brain, all proliferated and migrated neurons must extend their axonal and dendritic processes toward targets, which are often located at some distance. Upon contact with potential partners, neurons must undergo dramatic structural changes to become either a pre- or a postsynaptic neuron. This connectivity is cemented through specialized structures termed synapses. Both structurally and functionally, the newly formed synapses are, however, not static as they undergo consistent changes in order for an animal to meet its behavioral needs in a changing environment. These changes may be either in the form of new synapses or an enhancement of their synaptic efficacy, referred to as synaptic plasticity. Thus, synapse formation is not restricted to neurodevelopment; it is a process that remains active throughout life. As the brain ages, either the lack of neuronal activity or cell death render synapses dysfunctional, thus giving rise to neurodegenerative disorders. This review seeks to highlight salient steps that are involved in a neuron's journey, starting with the establishment, maturation, and consolidation of synapses; we particularly focus on identifying key players involved in the synaptogenic program. We hope that this endeavor will not only help the beginners in this field to understand how brain networks are assembled in the first place but also shed light on various neurodevelopmental, neurological, neurodegenerative, and neuropsychiatric disorders that involve synaptic inactivity or dysfunction.
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Affiliation(s)
- Shadab Batool
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Alberta, Canada
| | - Hussain Raza
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Jawwad Zaidi
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Saba Riaz
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Sean Hasan
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Naweed I Syed
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada.,Department of Cell Biology & Anatomy, University of Calgary, Alberta, Canada
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28
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Bal-Price A, Pistollato F, Sachana M, Bopp SK, Munn S, Worth A. Strategies to improve the regulatory assessment of developmental neurotoxicity (DNT) using in vitro methods. Toxicol Appl Pharmacol 2018; 354:7-18. [PMID: 29476865 PMCID: PMC6095942 DOI: 10.1016/j.taap.2018.02.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/05/2018] [Accepted: 02/13/2018] [Indexed: 01/23/2023]
Abstract
Currently, the identification of chemicals that have the potential to induce developmental neurotoxicity (DNT) is based on animal testing. Since at the regulatory level, systematic testing of DNT is not a standard requirement within the EU or USA chemical legislation safety assessment, DNT testing is only performed in higher tiered testing triggered based on chemical structure activity relationships or evidence of neurotoxicity in systemic acute or repeated dose toxicity studies. However, these triggers are rarely used and, in addition, do not always serve as reliable indicators of DNT, as they are generally based on observations in adult rodents. Therefore, there is a pressing need for developing alternative methodologies that can reliably support identification of DNT triggers, and more rapidly and cost-effectively support the identification and characterization of chemicals with DNT potential. We propose to incorporate mechanistic knowledge and data derived from in vitro studies to support various regulatory applications including: (a) the identification of potential DNT triggers, (b) initial chemical screening and prioritization, (c) hazard identification and characterization, (d) chemical biological grouping, and (e) assessment of exposure to chemical mixtures. Ideally, currently available cellular neuronal/glial models derived from human induced pluripotent stem cells (hiPSCs) should be used as they allow evaluation of chemical impacts on key neurodevelopmental processes, by reproducing different windows of exposure during human brain development. A battery of DNT in vitro test methods derived from hiPSCs could generate valuable mechanistic data, speeding up the evaluation of thousands of compounds present in industrial, agricultural and consumer products that lack safety data on DNT potential.
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Affiliation(s)
- Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy.
| | | | - Magdalini Sachana
- Organisation for Economic Co-operation and Development (OECD), 2 rue André Pascal, 75775 Paris, Cedex 16, France
| | | | - Sharon Munn
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Andrew Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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29
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Morrow S, Gosálvez J, López-Fernández C, Arroyo F, Holt WV, Guille MJ. Effects of freezing and activation on membrane quality and DNA damage in Xenopus tropicalis and Xenopus laevis spermatozoa. Reprod Fertil Dev 2018; 29:1556-1566. [PMID: 27692061 DOI: 10.1071/rd16190] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/04/2016] [Indexed: 12/21/2022] Open
Abstract
There is growing concern over the effect of sperm cryopreservation on DNA integrity and the subsequent development of offspring generated from this cryopreserved material. In the present study, membrane integrity and DNA stability of Xenopus laevis and Xenopus tropicalis spermatozoa were evaluated in response to cryopreservation with or without activation, a process that happens upon exposure to water to spermatozoa of some aquatic species. A dye exclusion assay revealed that sperm plasma membrane integrity in both species decreased after freezing, more so for X. laevis than X. tropicalis spermatozoa. The sperm chromatin dispersion (SCD) test showed that for both X. tropicalis and X. laevis, activated frozen spermatozoa produced the highest levels of DNA fragmentation compared with all fresh samples and frozen non-activated samples (P<0.05). Understanding the nature of DNA and membrane damage that occurs in cryopreserved spermatozoa from Xenopus species represents the first step in exploiting these powerful model organisms to understand the developmental consequences of fertilising with cryopreservation-damaged spermatozoa.
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Affiliation(s)
- S Morrow
- School of Biological Sciences and European Resource Centre, The University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - J Gosálvez
- Department of Biology, Genetics Unit, The Autonomous University of Madrid, 20849 Madrid, Spain
| | - C López-Fernández
- Department of Biology, Genetics Unit, The Autonomous University of Madrid, 20849 Madrid, Spain
| | - F Arroyo
- Department of Biology, Genetics Unit, The Autonomous University of Madrid, 20849 Madrid, Spain
| | - W V Holt
- Academic Department of Reproductive and Developmental Medicine, The University of Sheffield, Sheffield, S10 2SF, UK
| | - M J Guille
- School of Biological Sciences and European Resource Centre, The University of Portsmouth, Portsmouth, PO1 2DT, UK
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30
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Johan Arief MF, Choo BKM, Yap JL, Kumari Y, Shaikh MF. A Systematic Review on Non-mammalian Models in Epilepsy Research. Front Pharmacol 2018; 9:655. [PMID: 29997502 PMCID: PMC6030834 DOI: 10.3389/fphar.2018.00655] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 05/31/2018] [Indexed: 02/03/2023] Open
Abstract
Epilepsy is a common neurological disorder characterized by seizures which result in distinctive neurobiological and behavioral impairments. Not much is known about the causes of epilepsy, making it difficult to devise an effective cure for epilepsy. Moreover, clinical studies involving epileptogenesis and ictogenesis cannot be conducted in humans due to ethical reasons. As a result, animal models play a crucial role in the replication of epileptic seizures. In recent years, non-mammalian models have been given a primary focus in epilepsy research due to their advantages. This systematic review aims to summarize the importance of non-mammalian models in epilepsy research, such as in the screening of anti-convulsive compounds. The reason for this review is to integrate currently available information on the use and importance of non-mammalian models in epilepsy testing to aid in the planning of future studies as well as to provide an overview of the current state of this field. A PRISMA model was utilized and PubMed, Springer, ScienceDirect and SCOPUS were searched for articles published between January 2007 and November 2017. Fifty-one articles were finalized based on the inclusion/exclusion criteria and were discussed in this review. The results of this review demonstrated the current use of non-mammalian models in epilepsy research and reaffirmed their potential to supplement the typical rodent models of epilepsy in future research into both epileptogenesis and the treatment of epilepsy. This review also revealed a preference for zebrafish and fruit flies in lieu of other non-mammalian models, which is a shortcoming that should be corrected in future studies due to the great potential of these underutilized animal models.
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Affiliation(s)
- Muhammad Faiz Johan Arief
- MBBS Young Scholars Program, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia.,Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Brandon Kar Meng Choo
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Jia Ling Yap
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia.,School of Science, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Yatinesh Kumari
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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31
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Naumann B, Olsson L. Three-dimensional reconstruction of the cranial and anterior spinal nerves in early tadpoles of Xenopus laevis (Pipidae, Anura). J Comp Neurol 2018; 526:836-857. [PMID: 29218708 DOI: 10.1002/cne.24370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/26/2017] [Indexed: 01/29/2023]
Abstract
Xenopus laevis is one of the most widely used model organism in neurobiology. It is therefore surprising, that no detailed and complete description of the cranial nerves exists for this species. Using classical histological sectioning in combination with fluorescent whole mount antibody staining and micro-computed tomography we prepared a detailed innervation map and a freely-rotatable three-dimensional (3D) model of the cranial nerves and anterior-most spinal nerves of early X. laevis tadpoles. Our results confirm earlier descriptions of the pre-otic cranial nerves and present the first detailed description of the post-otic cranial nerves. Tracing the innervation, we found two previously undescribed head muscles (the processo-articularis and diaphragmatico-branchialis muscles) in X. laevis. Data on the cranial nerve morphology of tadpoles are scarce, and only one other species (Discoglossus pictus) has been described in great detail. A comparison of Xenopus and Discoglossus reveals a relatively conserved pattern of the post-otic and a more variable morphology of the pre-otic cranial nerves. Furthermore, the innervation map and the 3D models presented here can serve as an easily accessible basis to identify alterations of the innervation produced by experimental studies such as genetic gain- and loss of function experiments.
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Affiliation(s)
- Benjamin Naumann
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität, Jena, Germany
| | - Lennart Olsson
- Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller-Universität, Jena, Germany
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32
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Liu Z, Donnelly KB, Pratt KG. Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons. J Vis Exp 2018. [PMID: 29608176 DOI: 10.3791/57465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function. Here we describe how to perform the in vivo preparation, the original whole brain preparation, and a more recently developed horizontal brain slice preparation for obtaining whole cell patch clamp recordings from tectal neurons. Each preparation has unique experimental advantages. The in vivo preparation enables the recording of the direct response of tectal neurons to visual stimuli projected onto the eye. The whole brain preparation allows for the RGC axons to be activated in a highly controlled manner, and the horizontal brain slice preparation allows recording from across all layers of the tectum.
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Affiliation(s)
- Zhenyu Liu
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming
| | - Katelynne B Donnelly
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming
| | - Kara G Pratt
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming;
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33
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Pai VP, Pietak A, Willocq V, Ye B, Shi NQ, Levin M. HCN2 Rescues brain defects by enforcing endogenous voltage pre-patterns. Nat Commun 2018. [PMID: 29519998 PMCID: PMC5843655 DOI: 10.1038/s41467-018-03334-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Endogenous bioelectrical signaling coordinates cell behaviors toward correct anatomical outcomes. Lack of a model explaining spatialized dynamics of bioelectric states has hindered the understanding of the etiology of some birth defects and the development of predictive interventions. Nicotine, a known neuroteratogen, induces serious defects in brain patterning and learning. Our bio-realistic computational model explains nicotine’s effects via the disruption of endogenous bioelectrical gradients and predicts that exogenous HCN2 ion channels would restore the endogenous bioelectric prepatterns necessary for brain patterning. Voltage mapping in vivo confirms these predictions, and exogenous expression of the HCN2 ion channel rescues nicotine-exposed embryos, resulting in normal brain morphology and molecular marker expression, with near-normal learning capacity. By combining molecular embryology, electrophysiology, and computational modeling, we delineate a biophysical mechanism of developmental brain damage and its functional rescue. The authors have previously shown that membrane voltage can influence embryonic patterning during development. Here, the authors computationally model how nicotine disrupts Xenopus embryogenesis by perturbing voltage gradients, and rescue nicotine-inducted defects with HCN2 channel expression.
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Affiliation(s)
- Vaibhav P Pai
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Alexis Pietak
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Valerie Willocq
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA
| | - Bin Ye
- Veridian Biotechnology Limited, Biotech Center 2, Hong Kong, China
| | - Nian-Qing Shi
- Department of Developmental, Molecular, and Chemical Biology, Tufts University, Boston, MA, 02111, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, 02155, USA.
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34
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Herrera-Rincon C, Levin M. Booting up the organism during development: Pre-behavioral functions of the vertebrate brain in guiding body morphogenesis. Commun Integr Biol 2018; 11:e1433440. [PMID: 29497473 PMCID: PMC5824965 DOI: 10.1080/19420889.2018.1433440] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/19/2018] [Indexed: 01/24/2023] Open
Abstract
A recent study in Xenopus laevis embryos showed that the very early brain has important functions long before behavior. While the nascent brain is being constructed, it is required for normal patterning of the muscle and peripheral nerve networks, including those far away from the head. In addition to providing important developmental signals to remote tissues in normal embryogenesis, its presence is also able to render harmless exposure to specific chemicals that normally act as teratogens. These activities of the early brain can be partially compensated for in a brainless embryo by experimental modulation of neurotransmitter and ion channel signaling. Here, we discuss the major findings of this paper in the broader context of developmental physiology, neuroscience, and biomedicine. This novel function of the embryonic brain has significant implications, especially for understanding developmental toxicology and teratogenesis in the context of pharmaceutical and environmental reagents.
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Affiliation(s)
- Celia Herrera-Rincon
- Allen Discovery Center, and Department of Biology, Tufts University, Medford, MA, USA
| | - Michael Levin
- Allen Discovery Center, and Department of Biology, Tufts University, Medford, MA, USA
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35
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Use of genetically encoded, light-gated ion translocators to control tumorigenesis. Oncotarget 2017; 7:19575-88. [PMID: 26988909 PMCID: PMC4991402 DOI: 10.18632/oncotarget.8036] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 02/11/2016] [Indexed: 01/01/2023] Open
Abstract
It has long been known that the resting potential of tumor cells is depolarized relative to their normal counterparts. More recent work has provided evidence that resting potential is not just a readout of cell state: it regulates cell behavior as well. Thus, the ability to control resting potential in vivo would provide a powerful new tool for the study and treatment of tumors, a tool capable of revealing living-state physiological information impossible to obtain using molecular tools applied to isolated cell components. Here we describe the first use of optogenetics to manipulate ion-flux mediated regulation of membrane potential specifically to prevent and cause regression of oncogene-induced tumors. Injection of mutant-KRAS mRNA induces tumor-like structures with many documented similarities to tumors, in Xenopus tadpoles. We show that expression and activation of either ChR2D156A, a blue-light activated cation channel, or Arch, a green-light activated proton pump, both of which hyperpolarize cells, significantly lowers the incidence of KRAS tumor formation. Excitingly, we also demonstrate that activation of co-expressed light-activated ion translocators after tumor formation significantly increases the frequency with which the tumors regress in a process called normalization. These data demonstrate an optogenetic approach to dissect the biophysics of cancer. Moreover, they provide proof-of-principle for a novel class of interventions, directed at regulating cell state by targeting physiological regulators that can over-ride the presence of mutations.
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Zahn N, Levin M, Adams DS. The Zahn drawings: new illustrations of Xenopus embryo and tadpole stages for studies of craniofacial development. Development 2017; 144:2708-2713. [PMID: 28765211 PMCID: PMC5560046 DOI: 10.1242/dev.151308] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The embryos and tadpoles of the frog Xenopus are increasingly important subjects for studies of the development of the head and face - studies that are providing novel and crucial insight into the causes and prevention of a suite of devastating birth defects, as well as basic evolutionary and developmental biology. However, many studies are conducted on a range of embryonic stages that are not fully represented in the beloved Xenopus resource, Nieuwkoop and Faber's classic Normal Table of Xenopus laevis (Daudin) The lack of standardized images at these stages acts as a barrier to the efficient and accurate representation and communication of experimental methodology and expression data. To fill this gap, we have created 27 new high-quality illustrations. Like their oft-used predecessors from Nieuwkoop and Faber, these drawings can be freely downloaded and used, and will, we hope, serve as an essential resource for this important model system.
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Affiliation(s)
| | - Michael Levin
- Department of Biology and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155, USA.,Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Dany Spencer Adams
- Department of Biology and Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA 02155, USA
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Yoo Y, Jung J, Lee YN, Lee Y, Cho H, Na E, Hong J, Kim E, Lee JS, Lee JS, Hong C, Park SY, Wie J, Miller K, Shur N, Clow C, Ebel RS, DeBrosse SD, Henderson LB, Willaert R, Castaldi C, Tikhonova I, Bilgüvar K, Mane S, Kim KJ, Hwang YS, Lee SG, So I, Lim BC, Choi HJ, Seong JY, Shin YB, Jung H, Chae JH, Choi M. GABBR2mutations determine phenotype in rett syndrome and epileptic encephalopathy. Ann Neurol 2017; 82:466-478. [DOI: 10.1002/ana.25032] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 12/29/2022]
Affiliation(s)
- Yongjin Yoo
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
| | - Jane Jung
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Republic of Korea
| | - Yoo-Na Lee
- Graduate School of Medicine; Korea University; Seoul Republic of Korea
| | - Youngha Lee
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
| | - Hyosuk Cho
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
| | - Eunjung Na
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Republic of Korea
| | - JeaYeok Hong
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Republic of Korea
| | - Eunjin Kim
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Republic of Korea
| | - Jin Sook Lee
- Department of Pediatrics, Department of Genome Medicine and Science; Gachon University Gil Medical Center; Incheon Republic of Korea
| | - Je Sang Lee
- Department of Rehabilitation Medicine; Pusan National University College of Medicine; Pusan Republic of Korea
| | - Chansik Hong
- Department of Physiology; Chosun University School of Medicine; Kwangju Republic of Korea
| | - Sang-Yoon Park
- Department of Science in Korean Medicine, Cancer Preventive Material Developmental Research Center, College of Korean Medicine; Kyung Hee University; Seoul Republic of Korea
| | - Jinhong Wie
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
- Department of Physiology; Seoul National University College of Medicine; Seoul Republic of Korea
| | | | | | | | - Roseànne S. Ebel
- UH Cleveland Medical Center; Center for Human Genetics; Cleveland OH
| | | | | | | | | | | | - Kaya Bilgüvar
- Yale Center for Genome Analysis; West Haven CT
- Department of Genetics; Yale University School of Medicine; New Haven CT
| | - Shrikant Mane
- Yale Center for Genome Analysis; West Haven CT
- Department of Genetics; Yale University School of Medicine; New Haven CT
| | - Ki Joong Kim
- Department of Pediatrics, Seoul National University College of Medicine; Seoul National University Children's Hospital; Seoul Republic of Korea
| | - Yong Seung Hwang
- Department of Pediatrics, Seoul National University College of Medicine; Seoul National University Children's Hospital; Seoul Republic of Korea
| | - Seok-Geun Lee
- Department of Science in Korean Medicine, Cancer Preventive Material Developmental Research Center, College of Korean Medicine; Kyung Hee University; Seoul Republic of Korea
| | - Insuk So
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
- Department of Physiology; Seoul National University College of Medicine; Seoul Republic of Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University College of Medicine; Seoul National University Children's Hospital; Seoul Republic of Korea
| | - Hee-Jung Choi
- Department of Biological Sciences; Seoul National University College of Natural Sciences; Seoul Republic of Korea
| | - Jae Young Seong
- Graduate School of Medicine; Korea University; Seoul Republic of Korea
| | - Yong Beom Shin
- Department of Rehabilitation Medicine; Pusan National University College of Medicine; Pusan Republic of Korea
| | - Hosung Jung
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science; Yonsei University College of Medicine; Seoul Republic of Korea
| | - Jong-Hee Chae
- Department of Pediatrics, Seoul National University College of Medicine; Seoul National University Children's Hospital; Seoul Republic of Korea
| | - Murim Choi
- Department of Biomedical Sciences; Seoul National University College of Medicine; Seoul Republic of Korea
- Department of Pediatrics, Seoul National University College of Medicine; Seoul National University Children's Hospital; Seoul Republic of Korea
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Szabo M, Svensson Akusjärvi S, Saxena A, Liu J, Chandrasekar G, Kitambi SS. Cell and small animal models for phenotypic drug discovery. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:1957-1967. [PMID: 28721015 PMCID: PMC5500539 DOI: 10.2147/dddt.s129447] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The phenotype-based drug discovery (PDD) approach is re-emerging as an alternative platform for drug discovery. This review provides an overview of the various model systems and technical advances in imaging and image analyses that strengthen the PDD platform. In PDD screens, compounds of therapeutic value are identified based on the phenotypic perturbations produced irrespective of target(s) or mechanism of action. In this article, examples of phenotypic changes that can be detected and quantified with relative ease in a cell-based setup are discussed. In addition, a higher order of PDD screening setup using small animal models is also explored. As PDD screens integrate physiology and multiple signaling mechanisms during the screening process, the identified hits have higher biomedical applicability. Taken together, this review highlights the advantages gained by adopting a PDD approach in drug discovery. Such a PDD platform can complement target-based systems that are currently in practice to accelerate drug discovery.
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Affiliation(s)
- Mihaly Szabo
- Department of Microbiology Tumor, and Cell Biology
| | | | - Ankur Saxena
- Department of Microbiology Tumor, and Cell Biology
| | - Jianping Liu
- Department of Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
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Tandon P, Conlon F, Furlow JD, Horb ME. Expanding the genetic toolkit in Xenopus: Approaches and opportunities for human disease modeling. Dev Biol 2017; 426:325-335. [PMID: 27109192 PMCID: PMC5074924 DOI: 10.1016/j.ydbio.2016.04.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/23/2016] [Accepted: 04/12/2016] [Indexed: 11/29/2022]
Abstract
The amphibian model Xenopus, has been used extensively over the past century to study multiple aspects of cell and developmental biology. Xenopus offers advantages of a non-mammalian system, including high fecundity, external development, and simple housing requirements, with additional advantages of large embryos, highly conserved developmental processes, and close evolutionary relationship to higher vertebrates. There are two main species of Xenopus used in biomedical research, Xenopus laevis and Xenopus tropicalis; the common perception is that both species are excellent models for embryological and cell biological studies, but only Xenopus tropicalis is useful as a genetic model. The recent completion of the Xenopus laevis genome sequence combined with implementation of genome editing tools, such as TALENs (transcription activator-like effector nucleases) and CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated nucleases), greatly facilitates the use of both Xenopus laevis and Xenopus tropicalis for understanding gene function in development and disease. In this paper, we review recent advances made in Xenopus laevis and Xenopus tropicalis with TALENs and CRISPR-Cas and discuss the various approaches that have been used to generate knockout and knock-in animals in both species. These advances show that both Xenopus species are useful for genetic approaches and in particular counters the notion that Xenopus laevis is not amenable to genetic manipulations.
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Affiliation(s)
- Panna Tandon
- University of North Carolina McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, United States.
| | - Frank Conlon
- University of North Carolina McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, United States
| | - J David Furlow
- Deparment of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, United States
| | - Marko E Horb
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, United States.
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40
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Tussellino M, Ronca R, Carotenuto R, Pallotta MM, Furia M, Capriglione T. Chlorpyrifos exposure affects fgf8, sox9, and bmp4 expression required for cranial neural crest morphogenesis and chondrogenesis in Xenopus laevis embryos. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2016; 57:630-640. [PMID: 27669663 DOI: 10.1002/em.22057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 09/04/2016] [Indexed: 06/06/2023]
Abstract
Chlorpyrifos (CPF) is an organophosphate insecticide used primarily to control foliage and soil-borne insect pests on a variety of food and feed crops. In mammals, maternal exposure to CPF has been reported to induce dose-related abnormalities such as slower brain growth and cerebral cortex thinning. In lower vertebrates, for example, fish and amphibians, teratogenic activity of this compound is correlated with several anatomical alterations. Little is known about the effects of CPF on mRNA expression of genes involved in early development of the anatomical structures appearing abnormal in embryos. This study investigated the effects of exposure to different CPF concentrations (10, 15 and 20 mg/L) on Xenopus laevis embryos from stage 4/8 to stage 46. Some of the morphological changes we detected in CPF-exposed embryos included cranial neural crest cell (NCC)-derived structures. For this reason, we analyzed the expression of select genes involved in hindbrain patterning (egr2), cranial neural crest chondrogenesis, and craniofacial development (fgf8, bmp4, sox9, hoxa2 and hoxb2). We found that CPF exposure induced a reduction in transcription of all the genes involved in NCC-dependent chondrogenesis, with largest reductions in fgf8 and sox9; whereas, in hindbrain, we did not find any alterations in egr2 expression. Changes in the expression of fgf8, bmp4, and sox9, which are master regulators of several developmental pathways, have important implications. If these changes are confirmed to belong to a general pattern of alterations in vertebrates prenatally exposed to OP, they might be useful to assess damage during vertebrate embryo development. Environ. Mol. Mutagen. 57:589-604, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Margherita Tussellino
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy
| | - Raffaele Ronca
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy
| | - Rosa Carotenuto
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy
| | - Maria M Pallotta
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy
| | - Maria Furia
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy
| | - Teresa Capriglione
- Department of Biology, Università di Napoli "Federico II", Via Cinthia, 21, Napoli, 80126, Italy.
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Fragile X mental retardation protein knockdown in the developing Xenopus tadpole optic tectum results in enhanced feedforward inhibition and behavioral deficits. Neural Dev 2016; 11:14. [PMID: 27503008 PMCID: PMC4977860 DOI: 10.1186/s13064-016-0069-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/03/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Fragile X Syndrome is the leading monogenetic cause of autism and most common form of intellectual disability. Previous studies have implicated changes in dendritic spine architecture as the primary result of loss of Fragile X Mental Retardation Protein (FMRP), but recent work has shown that neural proliferation is decreased and cell death is increased with either loss of FMRP or overexpression of FMRP. The purpose of this study was to investigate the effects of loss of FMRP on behavior and cellular activity. METHODS We knocked down FMRP expression using morpholino oligos in the optic tectum of Xenopus laevis tadpoles and performed a series of behavioral and electrophysiological assays. We investigated visually guided collision avoidance, schooling, and seizure propensity. Using single cell electrophysiology, we assessed intrinsic excitability and synaptic connectivity of tectal neurons. RESULTS We found that FMRP knockdown results in decreased swimming speed, reduced schooling behavior and decreased seizure severity. In single cells, we found increased inhibition relative to excitation in response to sensory input. CONCLUSIONS Our results indicate that the electrophysiological development of single cells in the absence of FMRP is largely unaffected despite the large neural proliferation defect. The changes in behavior are consistent with an increase in inhibition, which could be due to either changes in cell number or altered inhibitory drive, and indicate that FMRP can play a significant role in neural development much earlier than previously thought.
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42
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Liu Z, Hamodi AS, Pratt KG. Early development and function of the Xenopus tadpole retinotectal circuit. Curr Opin Neurobiol 2016; 41:17-23. [PMID: 27475307 DOI: 10.1016/j.conb.2016.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/28/2016] [Accepted: 07/10/2016] [Indexed: 01/14/2023]
Abstract
The retinotectal circuit is the major component of the amphibian visual system. It is comprised of the retinal ganglion cells (RGCs) in the eye, which project their axons to the optic tectum and form synapses onto postsynaptic tectal neurons. The retinotectal circuit is relatively simple, and develops quickly: Xenopus tadpoles begin displaying retinotectal-dependent visual avoidance behaviors by approximately 7-8 days post-fertilization, early larval stage. In this review we first provide a summary of the dynamic development of the retinotectal circuit, including the microcircuitry formed by local tectal-tectal connections within the tectum. Second, we discuss the basic visual avoidance behavior generated specifically by this circuit, and how this behavior is being used as an assay to test visual system function.
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Affiliation(s)
- Zhenyu Liu
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, WY 82071, United States
| | - Ali S Hamodi
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, WY 82071, United States
| | - Kara G Pratt
- Department of Zoology and Physiology and Program in Neuroscience, University of Wyoming, Laramie, WY 82071, United States.
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Liu LS, Zhao LY, Wang SH, Jiang JP. Research proceedings on amphibian model organisms. DONG WU XUE YAN JIU = ZOOLOGICAL RESEARCH 2016; 37:237-45. [PMID: 27469255 PMCID: PMC4980064 DOI: 10.13918/j.issn.2095-8137.2016.4.237] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/10/2016] [Indexed: 12/26/2022]
Abstract
Model organisms have long been important in biology and medicine due to their specific characteristics. Amphibians, especially Xenopus, play key roles in answering fundamental questions on developmental biology, regeneration, genetics, and toxicology due to their large and abundant eggs, as well as their versatile embryos, which can be readily manipulated and developed in vivo. Furthermore, amphibians have also proven to be of considerable benefit in human disease research due to their conserved cellular developmental and genomic organization. This review gives a brief introduction on the progress and limitations of these animal models in biology and human disease research, and discusses the potential and challenge of Microhyla fissipes as a new model organism.
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Affiliation(s)
- Lu-Sha Liu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Lan-Ying Zhao
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shou-Hong Wang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China;University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian-Ping Jiang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
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Adams DS, Uzel SGM, Akagi J, Wlodkowic D, Andreeva V, Yelick PC, Devitt-Lee A, Pare JF, Levin M. Bioelectric signalling via potassium channels: a mechanism for craniofacial dysmorphogenesis in KCNJ2-associated Andersen-Tawil Syndrome. J Physiol 2016; 594:3245-70. [PMID: 26864374 PMCID: PMC4908029 DOI: 10.1113/jp271930] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/01/2016] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Xenopus laevis craniofacial development is a good system for the study of Andersen-Tawil Syndrome (ATS)-associated craniofacial anomalies (CFAs) because (1) Kcnj2 is expressed in the nascent face; (2) molecular-genetic and biophysical techniques are available for the study of ion-dependent signalling during craniofacial morphogenesis; (3) as in humans, expression of variant Kcnj2 forms in embryos causes a muscle phenotype; and (4) variant forms of Kcnj2 found in human patients, when injected into frog embryos, cause CFAs in the same cell lineages. Forced expression of WT or variant Kcnj2 changes the normal pattern of Vmem (resting potential) regionalization found in the ectoderm of neurulating embryos, and changes the normal pattern of expression of ten different genetic regulators of craniofacial development, including markers of cranial neural crest and of placodes. Expression of other potassium channels and two different light-activated channels, all of which have an effect on Vmem , causes CFAs like those induced by injection of Kcnj2 variants. In contrast, expression of Slc9A (NHE3), an electroneutral ion channel, and of GlyR, an inactive Cl(-) channel, do not cause CFAs, demonstrating that correct craniofacial development depends on a pattern of bioelectric states, not on ion- or channel-specific signalling. Using optogenetics to control both the location and the timing of ion flux in developing embryos, we show that affecting Vmem of the ectoderm and no other cell layers is sufficient to cause CFAs, but only during early neurula stages. Changes in Vmem induced late in neurulation do not affect craniofacial development. We interpret these data as strong evidence, consistent with our hypothesis, that ATS-associated CFAs are caused by the effect of variant Kcnj2 on the Vmem of ectodermal cells of the developing face. We predict that the critical time is early during neurulation, and the critical cells are the ectodermal cranial neural crest and placode lineages. This points to the potential utility of extant, ion flux-modifying drugs as treatments to prevent CFAs associated with channelopathies such as ATS. ABSTRACT Variants in potassium channel KCNJ2 cause Andersen-Tawil Syndrome (ATS); the induced craniofacial anomalies (CFAs) are entirely unexplained. We show that KCNJ2 is expressed in Xenopus and mouse during the earliest stages of craniofacial development. Misexpression in Xenopus of KCNJ2 carrying ATS-associated mutations causes CFAs in the same structures affected in humans, changes the normal pattern of membrane voltage potential regionalization in the developing face and disrupts expression of important craniofacial patterning genes, revealing the endogenous control of craniofacial patterning by bioelectric cell states. By altering cells' resting potentials using other ion translocators, we show that a change in ectodermal voltage, not tied to a specific protein or ion, is sufficient to cause CFAs. By adapting optogenetics for use in non-neural cells in embryos, we show that developmentally patterned K(+) flux is required for correct regionalization of the resting potentials and for establishment of endogenous early gene expression domains in the anterior ectoderm, and that variants in KCNJ2 disrupt this regionalization, leading to the CFAs seen in ATS patients.
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Affiliation(s)
- Dany Spencer Adams
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Sebastien G M Uzel
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Jin Akagi
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Donald Wlodkowic
- School of Applied Sciences, RMIT University, Melbourne, Australia
| | - Viktoria Andreeva
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University School of Dental Medicine, Boston, MA 02111, USA
| | - Pamela Crotty Yelick
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University School of Dental Medicine, Boston, MA 02111, USA
| | - Adrian Devitt-Lee
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Jean-Francois Pare
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
| | - Michael Levin
- Department of Biology and Tufts Centre for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Medford, MA, 02155, USA
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Haselman JT, Sakurai M, Watanabe N, Goto Y, Onishi Y, Ito Y, Onoda Y, Kosian PA, Korte JJ, Johnson RD, Iguchi T, Degitz SJ. Development of the Larval Amphibian Growth and Development Assay: Effects of benzophenone-2 exposure inXenopus laevisfrom embryo to juvenile. J Appl Toxicol 2016; 36:1651-1661. [DOI: 10.1002/jat.3336] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/22/2016] [Accepted: 03/22/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Jonathan T. Haselman
- US EPA ORD/NHEERL/Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Maki Sakurai
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Naoko Watanabe
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Yasushi Goto
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Yuta Onishi
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Yuki Ito
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Yu Onoda
- Institute of Environmental Ecology; IDEA Consultants Inc.; 1334-5 Riemon, Yaizu Shizuoka 421-0212 Japan
| | - Patricia A. Kosian
- US EPA ORD/NHEERL/Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Joseph J. Korte
- US EPA ORD/NHEERL/Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Rodney D. Johnson
- US EPA ORD/NHEERL/Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
| | - Taisen Iguchi
- Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences; 5-1 Higashiyama, Myodaiji Okazaki Aichi 444-8787 Japan
| | - Sigmund J. Degitz
- US EPA ORD/NHEERL/Mid-Continent Ecology Division; 6201 Congdon Blvd Duluth MN 55804 USA
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46
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Rothman GR, Blackiston DJ, Levin M. Color and intensity discrimination in Xenopus laevis tadpoles. Anim Cogn 2016; 19:911-9. [PMID: 27146661 DOI: 10.1007/s10071-016-0990-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 04/19/2016] [Accepted: 04/25/2016] [Indexed: 12/12/2022]
Abstract
Investigations into the physiology of Xenopus laevis have the potential to greatly accelerate biomedical research, especially concerning neural plasticity and sensory systems, but are limited by the lack of available information on behavioral learning in this species. Here, we attempt to lay the foundations for a behavioral assay in Xenopus that can be used in conjunction with biological manipulations. We tested cohorts of Xenopus tadpoles across four light-mediated active-avoidance experiments, using either wavelength or intensity as the salient discriminative cue. In the wavelength task, we determine a baseline learning rate and characterize retention of learning, identifying active extinction effects as far more potent than the passage of time in the loss of behavior. In the intensity task, we examine the effects of varying differences between the discriminative stimuli on acquisition and extinction and identify a critical range of intensity differences where learning changes. The results of our experiments demonstrate that Xenopus is a tractable model organism for cognitive research and can learn a variety of associative tasks in the laboratory settings. These data reveal new aspects of the Xenopus larval visual processing system and facilitate future research between cognitive methods and biological/chemical manipulations to study mechanisms of brain structure and function.
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Affiliation(s)
- Gabriel R Rothman
- Department of Biology, Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA, 02155, USA
| | - Douglas J Blackiston
- Department of Biology, Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA, 02155, USA
| | - Michael Levin
- Department of Biology, Center for Regenerative and Developmental Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA, 02155, USA.
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47
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Sullivan KG, Levin M. Neurotransmitter signaling pathways required for normal development in Xenopus laevis embryos: a pharmacological survey screen. J Anat 2016; 229:483-502. [PMID: 27060969 DOI: 10.1111/joa.12467] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2016] [Indexed: 01/08/2023] Open
Abstract
Neurotransmitters are not only involved in brain function but are also important signaling molecules for many diverse cell types. Neurotransmitters are widely conserved, from evolutionarily ancient organisms lacking nervous systems through man. Here, results are reported from a loss- and gain-of-function survey, using pharmacological modulators of several neurotransmitter pathways to examine possible roles for these pathways in normal embryogenesis. Applying reagents targeting the glutamatergic, adrenergic and dopaminergic pathways to embryos of Xenopus laevis from gastrulation to organogenesis stages, we observed and quantified numerous malformations, including craniofacial defects, hyperpigmentation, muscle mispatterning and miscoiling of the gut. These data implicate several key neurotransmitters in new embryonic patterning roles, reveal novel earlier stages for processes involved in eye development, suggest new targets for subsequent molecular-genetic investigation, and highlight the necessity for in-depth toxicology studies of psychoactive compounds to which human embryos might be exposed during pregnancy.
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Affiliation(s)
- Kelly G Sullivan
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA, USA
| | - Michael Levin
- Biology Department, Center for Regenerative and Developmental Biology, Tufts University, Medford, MA, USA
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48
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Durand BC. Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo. J Vis Exp 2016:e53474. [PMID: 26863402 DOI: 10.3791/53474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Understanding the genetic programs underlying neural development is an important goal of developmental and stem cell biology. In the amphibian blastula, cells from the roof of the blastocoel are pluripotent. These cells can be isolated, and programmed to generate various tissues through manipulation of genes expression or induction by morphogens. In this manuscript protocols are described for the use of Xenopus laevis blastocoel roof explants as an assay system to investigate key in vivo and in vitro features of early neural development. These protocols allow the investigation of fate acquisition, cell migration behaviors, and cell autonomous and non-autonomous properties. The blastocoel roof explants can be cultured in a serum-free defined medium and grafted into host embryos. This transplantation into an embryo allows the investigation of the long-term lineage commitment, the inductive properties, and the behavior of transplanted cells in vivo. These assays can be exploited to investigate molecular mechanisms, cellular processes and gene regulatory networks underlying neural development. In the context of regenerative medicine, these assays provide a means to generate neural-derived cell types in vitro that could be used in drug screening.
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Affiliation(s)
- Beatrice C Durand
- Institut Curie; UMR 3387, CNRS; PSL Research University; Université Paris-Sud;
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49
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Davis GM, Haas MA, Pocock R. MicroRNAs: Not "Fine-Tuners" but Key Regulators of Neuronal Development and Function. Front Neurol 2015; 6:245. [PMID: 26635721 PMCID: PMC4656843 DOI: 10.3389/fneur.2015.00245] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 11/09/2015] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs (miRNAs) are a class of short non-coding RNAs that operate as prominent post-transcriptional regulators of eukaryotic gene expression. miRNAs are abundantly expressed in the brain of most animals and exert diverse roles. The anatomical and functional complexity of the brain requires the precise coordination of multilayered gene regulatory networks. The flexibility, speed, and reversibility of miRNA function provide precise temporal and spatial gene regulatory capabilities that are crucial for the correct functioning of the brain. Studies have shown that the underlying molecular mechanisms controlled by miRNAs in the nervous systems of invertebrate and vertebrate models are remarkably conserved in humans. We endeavor to provide insight into the roles of miRNAs in the nervous systems of these model organisms and discuss how such information may be used to inform regarding diseases of the human brain.
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Affiliation(s)
- Gregory M. Davis
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Matilda A. Haas
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
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50
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Ciarleglio CM, Khakhalin AS, Wang AF, Constantino AC, Yip SP, Aizenman CD. Multivariate analysis of electrophysiological diversity of Xenopus visual neurons during development and plasticity. eLife 2015; 4. [PMID: 26568314 PMCID: PMC4728129 DOI: 10.7554/elife.11351] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/12/2015] [Indexed: 12/26/2022] Open
Abstract
Biophysical properties of neurons become increasingly diverse over development, but mechanisms underlying and constraining this diversity are not fully understood. Here we investigate electrophysiological characteristics of Xenopus tadpole midbrain neurons across development and during homeostatic plasticity induced by patterned visual stimulation. We show that in development tectal neuron properties not only change on average, but also become increasingly diverse. After sensory stimulation, both electrophysiological diversity and functional differentiation of cells are reduced. At the same time, the amount of cross-correlations between cell properties increase after patterned stimulation as a result of homeostatic plasticity. We show that tectal neurons with similar spiking profiles often have strikingly different electrophysiological properties, and demonstrate that changes in intrinsic excitability during development and in response to sensory stimulation are mediated by different underlying mechanisms. Overall, this analysis and the accompanying dataset provide a unique framework for further studies of network maturation in Xenopus tadpoles.
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Affiliation(s)
- Christopher M Ciarleglio
- Biology Program, Brown University, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
| | - Arseny S Khakhalin
- Biology Program, Bard College, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
| | - Angelia F Wang
- Biology Program, Bard College, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
| | - Alexander C Constantino
- Biology Program, Bard College, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
| | - Sarah P Yip
- Biology Program, Bard College, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
| | - Carlos D Aizenman
- Biology Program, Bard College, Annandale-on-Hudson, United States.,Department of Neuroscience, Brown University, Providence, United States
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