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Jones RA, Renshaw MJ, Barry DJ. Automated staging of zebrafish embryos with deep learning. Life Sci Alliance 2024; 7:e202302351. [PMID: 37884343 PMCID: PMC10602791 DOI: 10.26508/lsa.202302351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/14/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023] Open
Abstract
The zebrafish (Danio rerio) is an important biomedical model organism used in many disciplines. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype. However, the detection and quantification of these delays is often achieved through manual observation, which is both time-consuming and subjective. We present KimmelNet, a deep learning model trained to predict embryo age (hours post fertilisation) from 2D brightfield images. KimmelNet's predictions agree closely with established staging methods and can detect developmental delays between populations with high confidence using as few as 100 images. Moreover, KimmelNet generalises to previously unseen data, with transfer learning enhancing its performance. With the ability to analyse tens of thousands of standard brightfield microscopy images on a timescale of minutes, we envisage that KimmelNet will be a valuable resource for the developmental biology community. Furthermore, the approach we have used could easily be adapted to generate models for other organisms.
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Affiliation(s)
- Rebecca A Jones
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- https://ror.org/04tnbqb63 Developmental Biology Laboratory, The Francis Crick Institute, London, UK
| | - Matthew J Renshaw
- https://ror.org/04tnbqb63 Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, London, UK
| | - David J Barry
- https://ror.org/04tnbqb63 Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, London, UK
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2
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Hariharan S, Chauhan S, Marcharla E, Alphonse CRW, Rajaretinam RK, Ganesan S. Developmental toxicity and neurobehavioral effects of sodium selenite and selenium nanoparticles on zebrafish embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 266:106791. [PMID: 38070396 DOI: 10.1016/j.aquatox.2023.106791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/15/2023] [Accepted: 12/02/2023] [Indexed: 01/02/2024]
Abstract
Selenium, a trace mineral, is essential for several physiological processes in humans and animals. It is an antioxidant vital for the immunological response, DNA synthesis, thyroid hormone metabolism, and antioxidant defense enzymes. Zebrafish embryos and larvae were exposed to different concentrations of sodium selenite (SodSe) and selenium nanoparticles (SeNs) at various developmental stages. The study evaluated the impact of SodSe and SeNs on larvae survival, hatching rate, and morphological abnormalities. Also, acridine orange staining was used to analyze the apoptotic cell death, and behavioral tests were conducted to assess anxiety-like behaviors. The results showed that both SodSe and SeNs influence the development and neurobehavior of zebrafish larvae in a concentration-dependent manner. SodSe at high concentration causes low survival rates, delayed hatching, and increased morphological defects in zebrafish larvae. In addition, exposure to SodSe resulted in elevated apoptosis in different larval tissues. Zebrafish larvae treated with SodSe and SeNs exhibited anxiety-like behaviour, increased thigmotaxis, less exploratory behaviour, and less swimming patterns. The nerve conductions and stimuli responses evaluated through acetylcholine esterase (AChE) and cortisol assays, revealed a decrease in the activity in a dose-dependent manner of SodSe and SeNs. Interestingly, the effects of SeNs were lower even at higher concentrations when compared with SodSe at lower concentrations on zebrafish embryos. This shows that SeNs synthesized through biological methods may be less toxic and may have lower effect on the development and neurobehavior of zebrafish larvae. Thus, our study confirms the cytotoxic and neurobehavioral effects of SodSe and suggests the use of SeNs at lower concentration to provide insights into better understanding of developmental stages and metabolic pathways in zebrafish larvae.
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Affiliation(s)
- Sneha Hariharan
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, Tamil Nadu, 603203, India
| | - Smarika Chauhan
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, Tamil Nadu, 603203, India
| | - Eswar Marcharla
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, Tamil Nadu, 603203, India
| | - Carlton Ranjith Wilson Alphonse
- Neuroscience Lab, Molecular and Nanomedicine Research Unit, Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Rajesh Kannan Rajaretinam
- Neuroscience Lab, Molecular and Nanomedicine Research Unit, Centre for Nanoscience and Nanotechnology, Sathyabama Institute of Science and Technology, Chennai, Tamil Nadu, India; Centre for Molecular and Translational Medicine, School of Biomedical Sciences, Galgotias University, Yamuna Expressway, Gautam Buddh Nagar, Greater Noida-203201 NCR India
| | - Swamynathan Ganesan
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, Tamil Nadu, 603203, India.
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3
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Geyer N, Kaminsky S, Confino S, Livne ZBM, Gothilf Y, Foulkes NS, Vallone D. Establishment of cell lines from individual zebrafish embryos. Lab Anim 2023; 57:518-528. [PMID: 36896487 DOI: 10.1177/00236772231157162] [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] [Indexed: 03/11/2023]
Abstract
With the increasing use of fish as model species for research, cell cultures derived from caudal fin explants as well as pre-hatching stage embryos have provided powerful in vitro tools that can complement or serve as an ethically more acceptable alternative to live animal experiments. The widely-used protocols to establish these lines require, as a starting point, homogeneous pools of embryos or viable adult fish which are large enough for collecting sufficient fin tissue. This excludes the use of fish lines with adverse phenotypes or lines that exhibit mortality at early developmental stages and so can only be propagated as heterozygotes. Specifically, when no visually overt mutant phenotype is detectable for identifying homozygous mutants at early embryonic stages, it is then impossible to sort pools of embryos with the same genotypes to generate cell lines from the progeny of a heterozygote in-cross. Here, we describe a simple protocol to generate cell lines on a large scale starting from individual early embryos that can subsequently be genotyped by polymerase chain reaction. This protocol should help to establish fish cell culture models as a routine approach for the functional characterization of genetic changes in fish models such as the zebrafish. Furthermore, it should contribute to a reduction of experiments which are ethically discouraged to avoid pain and distress.
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Affiliation(s)
- Nathalie Geyer
- Institute for Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology, Germany
| | - Sabrina Kaminsky
- Institute for Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology, Germany
- Centre for Organismal Studies Heidelberg, Ruprecht-Karls-Universität Heidelberg, Germany
| | - Shir Confino
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel-Aviv University, Israel
| | - Zohar Ben-Moshe Livne
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel-Aviv University, Israel
| | - Yoav Gothilf
- School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel-Aviv University, Israel
- Sagol School of Neuroscience, Tel-Aviv University, Israel
| | - Nicholas S Foulkes
- Institute for Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology, Germany
- Centre for Organismal Studies Heidelberg, Ruprecht-Karls-Universität Heidelberg, Germany
| | - Daniela Vallone
- Institute for Biological and Chemical Systems-Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology, Germany
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Jones RA, Renshaw MJ, Barry DJ, Smith JC. Automated staging of zebrafish embryos using machine learning. Wellcome Open Res 2023; 7:275. [PMID: 37614774 PMCID: PMC10442596 DOI: 10.12688/wellcomeopenres.18313.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 11/25/2023] Open
Abstract
The zebrafish ( Danio rerio), is an important biomedical model organism used in many disciplines, including development, disease modeling and toxicology, to better understand vertebrate biology. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype, and accurate characterization of such delays is imperative. Despite this, the only way at present to identify and quantify these delays is through manual observation, which is both time-consuming and subjective. Machine learning approaches in biology are rapidly becoming part of the toolkit used by researchers to address complex questions. In this work, we introduce a machine learning-based classifier that has been trained to detect temporal developmental differences across groups of zebrafish embryos. Our classifier is capable of rapidly analyzing thousands of images, allowing comparisons of developmental temporal rates to be assessed across and between experimental groups of embryos. Finally, as our classifier uses images obtained from a standard live-imaging widefield microscope and camera set-up, we envisage it will be readily accessible to the zebrafish community, and prove to be a valuable resource.
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Affiliation(s)
- Rebecca A. Jones
- Developmental Biology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Matthew J. Renshaw
- Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - David J. Barry
- Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - James C. Smith
- Developmental Biology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
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5
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Jones RA, Renshaw MJ, Barry DJ, Smith JC. Automated staging of zebrafish embryos using machine learning. Wellcome Open Res 2023; 7:275. [PMID: 37614774 PMCID: PMC10442596 DOI: 10.12688/wellcomeopenres.18313.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 08/25/2023] Open
Abstract
The zebrafish ( Danio rerio), is an important biomedical model organism used in many disciplines, including development, disease modeling and toxicology, to better understand vertebrate biology. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype, and accurate characterization of such delays is imperative. Despite this, the only way at present to identify and quantify these delays is through manual observation, which is both time-consuming and subjective. Machine learning approaches in biology are rapidly becoming part of the toolkit used by researchers to address complex questions. In this work, we introduce a machine learning-based classifier that has been trained to detect temporal developmental differences across groups of zebrafish embryos. Our classifier is capable of rapidly analyzing thousands of images, allowing comparisons of developmental temporal rates to be assessed across and between experimental groups of embryos. Finally, as our classifier uses images obtained from a standard live-imaging widefield microscope and camera set-up, we envisage it will be readily accessible to the zebrafish community, and prove to be a valuable resource.
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Affiliation(s)
- Rebecca A. Jones
- Developmental Biology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Matthew J. Renshaw
- Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - David J. Barry
- Crick Advanced Light Microscopy (CALM), The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - James C. Smith
- Developmental Biology Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
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6
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Jones RA, Renshaw MJ, Barry DJ, Smith JC. Automated staging of zebrafish embryos using machine learning. Wellcome Open Res 2023. [DOI: 10.12688/wellcomeopenres.18313.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
The zebrafish (Danio rerio), is an important biomedical model organism used in many disciplines, including development, disease modeling and toxicology, to better understand vertebrate biology. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype, and accurate characterization of such delays is imperative. Despite this, the only way at present to identify and quantify these delays is through manual observation, which is both time-consuming and subjective. Machine learning approaches in biology are rapidly becoming part of the toolkit used by researchers to address complex questions. In this work, we introduce a machine learning-based classifier that has been trained to detect temporal developmental differences across groups of zebrafish embryos. Our classifier is capable of rapidly analyzing thousands of images, allowing comparisons of developmental temporal rates to be assessed across and between experimental groups of embryos. Finally, as our classifier uses images obtained from a standard live-imaging widefield microscope and camera set-up, we envisage it will be readily accessible to the zebrafish community, and prove to be a valuable resource.
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7
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Ichii S, Matsuoka I, Okazaki F, Shimada Y. Zebrafish Models for Skeletal Muscle Senescence: Lessons from Cell Cultures and Rodent Models. Molecules 2022; 27:molecules27238625. [PMID: 36500717 PMCID: PMC9739860 DOI: 10.3390/molecules27238625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/08/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
Human life expectancy has markedly increased over the past hundred years. Consequently, the percentage of elderly people is increasing. Aging and sarcopenic changes in skeletal muscles not only reduce locomotor activities in elderly people but also increase the chance of trauma, such as bone fractures, and the incidence of other diseases, such as metabolic syndrome, due to reduced physical activity. Exercise therapy is currently the only treatment and prevention approach for skeletal muscle aging. In this review, we aimed to summarize the strategies for modeling skeletal muscle senescence in cell cultures and rodents and provide future perspectives based on zebrafish models. In cell cultures, in addition to myoblast proliferation and myotube differentiation, senescence induction into differentiated myotubes is also promising. In rodents, several models have been reported that reflect the skeletal muscle aging phenotype or parts of it, including the accelerated aging models. Although there are fewer models of skeletal muscle aging in zebrafish than in mice, various models have been reported in recent years with the development of CRISPR/Cas9 technology, and further advancements in the field using zebrafish models are expected in the future.
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Affiliation(s)
- Shogo Ichii
- Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan
| | - Izumi Matsuoka
- Graduate School of Regional Innovation Studies, Mie University, Tsu, Mie 514-8507, Japan
| | - Fumiyoshi Okazaki
- Graduate School of Bioresources, Mie University, Tsu, Mie 514-8507, Japan
- Zebrafish Drug Screening Center, Mie University, Tsu, Mie 514-8507, Japan
| | - Yasuhito Shimada
- Zebrafish Drug Screening Center, Mie University, Tsu, Mie 514-8507, Japan
- Department of Bioinformatics, Mie University Advanced Science Research Promotion Center, Tsu, Mie 514-8507, Japan
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
- Correspondence: ; Tel.: +81-592-31-5411
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8
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Torres-Pérez JV, Anagianni S, Mech AM, Havelange W, García-González J, Fraser SE, Vallortigara G, Brennan CH. baz1b loss-of-function in zebrafish produces phenotypic alterations consistent with the domestication syndrome. iScience 2022; 26:105704. [PMID: 36582821 PMCID: PMC9793288 DOI: 10.1016/j.isci.2022.105704] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/15/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
BAZ1B is a ubiquitously expressed nuclear protein with roles in chromatin remodeling, DNA replication and repair, and transcription. Reduced BAZ1B expression disrupts neuronal and neural crest development. Variation in the activity of BAZ1B has been proposed to underly morphological and behavioral aspects of domestication through disruption of neural crest development. Knockdown of baz1b in Xenopus embryos and Baz1b loss-of-function (LoF) in mice leads to craniofacial defects consistent with this hypothesis. We generated baz1b LoF zebrafish using CRISPR/Cas9 gene editing to test the hypothesis that baz1b regulates behavioral phenotypes associated with domestication in addition to craniofacial features. Zebrafish with baz1b LoF show mild underdevelopment at larval stages and distinctive craniofacial features later in life. Mutant zebrafish show reduced anxiety-associated phenotypes and an altered ontogeny of social behaviors. Thus, in zebrafish, developmental deficits in baz1b recapitulate both morphological and behavioral phenotypes associated with the domestication syndrome in other species.
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Affiliation(s)
- Jose V. Torres-Pérez
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
- Departament de Biologia Cel·lular, Biologia Funcional i Antropologia física, Fac. de CC. Biològiques, Universitat de València, C/ Dr. Moliner 50, Burjassot, València 46100, Spain
- Corresponding author
| | - Sofia Anagianni
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Aleksandra M. Mech
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
| | - William Havelange
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Judit García-González
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
- Department of Genetics and Genomic Sciences, Icahn School of Medicine, Mount Sinai, New York, NY 10029, USA
| | - Scott E. Fraser
- Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA, USA
| | | | - Caroline H. Brennan
- School of Biological and Behavioural Sciences, Queen Mary University of London, London E1 4NS, UK
- Corresponding author
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9
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Mehta S, Campbell H, Drummond CJ, Li K, Murray K, Slatter T, Bourdon JC, Braithwaite AW. Adaptive homeostasis and the p53 isoform network. EMBO Rep 2021; 22:e53085. [PMID: 34779563 PMCID: PMC8647153 DOI: 10.15252/embr.202153085] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 10/12/2021] [Accepted: 10/28/2021] [Indexed: 12/25/2022] Open
Abstract
All living organisms have developed processes to sense and address environmental changes to maintain a stable internal state (homeostasis). When activated, the p53 tumour suppressor maintains cell and organ integrity and functions in response to homeostasis disruptors (stresses) such as infection, metabolic alterations and cellular damage. Thus, p53 plays a fundamental physiological role in maintaining organismal homeostasis. The TP53 gene encodes a network of proteins (p53 isoforms) with similar and distinct biochemical functions. The p53 network carries out multiple biological activities enabling cooperation between individual cells required for long‐term survival of multicellular organisms (animals) in response to an ever‐changing environment caused by mutation, infection, metabolic alteration or damage. In this review, we suggest that the p53 network has evolved as an adaptive response to pathogen infections and other environmental selection pressures.
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Affiliation(s)
- Sunali Mehta
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Hamish Campbell
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand
| | - Catherine J Drummond
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Kunyu Li
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand
| | - Kaisha Murray
- Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Tania Slatter
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Jean-Christophe Bourdon
- Dundee Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - Antony W Braithwaite
- Department of Pathology, School of Medicine, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Biodiscovery, University of Otago, Dunedin, New Zealand
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10
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Salanga CM, Salanga MC. Genotype to Phenotype: CRISPR Gene Editing Reveals Genetic Compensation as a Mechanism for Phenotypic Disjunction of Morphants and Mutants. Int J Mol Sci 2021; 22:ijms22073472. [PMID: 33801686 PMCID: PMC8036752 DOI: 10.3390/ijms22073472] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022] Open
Abstract
Forward genetic screens have shown the consequences of deleterious mutations; however, they are best suited for model organisms with fast reproductive rates and large broods. Furthermore, investigators must faithfully identify changes in phenotype, even if subtle, to realize the full benefit of the screen. Reverse genetic approaches also probe genotype to phenotype relationships, except that the genetic targets are predefined. Until recently, reverse genetic approaches relied on non-genomic gene silencing or the relatively inefficient, homology-dependent gene targeting for loss-of-function generation. Fortunately, the flexibility and simplicity of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system has revolutionized reverse genetics, allowing for the precise mutagenesis of virtually any gene in any organism at will. The successful integration of insertions/deletions (INDELs) and nonsense mutations that would, at face value, produce the expected loss-of-function phenotype, have been shown to have little to no effect, even if other methods of gene silencing demonstrate robust loss-of-function consequences. The disjunction between outcomes has raised important questions about our understanding of genotype to phenotype and highlights the capacity for compensation in the central dogma. This review describes recent studies in which genomic compensation appears to be at play, discusses the possible compensation mechanisms, and considers elements important for robust gene loss-of-function studies.
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Affiliation(s)
- Cristy M. Salanga
- Office of the Vice President for Research, Northern Arizona University, Flagstaff, AZ 86011, USA;
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Matthew C. Salanga
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
- Correspondence:
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Probst J, Kölker S, Okun JG, Kumar A, Gursky E, Posset R, Hoffmann GF, Peravali R, Zielonka M. Chronic hyperammonemia causes a hypoglutamatergic and hyperGABAergic metabolic state associated with neurobehavioral abnormalities in zebrafish larvae. Exp Neurol 2020; 331:113330. [PMID: 32339612 DOI: 10.1016/j.expneurol.2020.113330] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/29/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022]
Abstract
Chronic hyperammonemia is a common condition affecting individuals with inherited urea cycle disorders resulting in progressive cognitive impairment and behavioral abnormalities. Altered neurotransmission has been proposed as major source of neuronal dysfunction during chronic hyperammonemia, but the molecular pathomechanism has remained incompletely understood. Here we show that chronic exposure to ammonium acetate induces locomotor dysfunction and abnormal feeding behavior in zebrafish larvae, indicative for an impairment of higher brain functions. Biochemically, chronically elevated ammonium concentrations cause enhanced activity of glutamate decarboxylase isoforms GAD1 and GAD2 with increased formation of GABA and concomitant depletion of glutamate, ultimately leading to a dysfunctional hypoglutamatergic and hyperGABAergic metabolic state. Moreover, elevated GABA concentrations are accompanied by increased expression of GABAA receptor subunits alpha-1, gamma-2 and delta, supporting the notion of an increased GABA tone in chronic hyperammonemia. Propionate oxidation as major anaplerotic reaction sufficiently compensates for the transamination-dependent withdrawal of 2-oxoglutarate, thereby preventing bioenergetic dysfunction under chronic hyperammonemic conditions. Thus, our study extends the hypothesis of alterations in the glutamatergic and GABAergic system being an important pathophysiological factor causing neurobehavioral impairment in chronic hyperammonemia. Given that zebrafish larvae have already been successfully used for high-throughput identification of novel compounds to treat inherited neurological diseases, the reported zebrafish model should be considered an important tool for systematic drug screening targeting altered glutamatergic and GABAergic metabolism under chronic hyperammonemic conditions in the future.
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Affiliation(s)
- Joris Probst
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Amrish Kumar
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Eduard Gursky
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Roland Posset
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ravindra Peravali
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Matthias Zielonka
- Center for Child and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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