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Neal SJ, Rajasekaran A, Jusić N, Taylor L, Read M, Alfandari D, Pignoni F, Moody SA. Using Xenopus to discover new candidate genes involved in BOR and other congenital hearing loss syndromes. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:212-240. [PMID: 37830236 PMCID: PMC11014897 DOI: 10.1002/jez.b.23222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/15/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023]
Abstract
Hearing in infants is essential for brain development, acquisition of verbal language skills, and development of social interactions. Therefore, it is important to diagnose hearing loss soon after birth so that interventions can be provided as early as possible. Most newborns in the United States are screened for hearing deficits and commercially available next-generation sequencing hearing loss panels often can identify the causative gene, which may also identify congenital defects in other organs. One of the most prevalent autosomal dominant congenital hearing loss syndromes is branchio-oto-renal syndrome (BOR), which also presents with defects in craniofacial structures and the kidney. Currently, mutations in three genes, SIX1, SIX5, and EYA1, are known to be causative in about half of the BOR patients that have been tested. To uncover new candidate genes that could be added to congenital hearing loss genetic screens, we have combined the power of Drosophila mutants and protein biochemical assays with the embryological advantages of Xenopus, a key aquatic animal model with a high level of genomic similarity to human, to identify potential Six1 transcriptional targets and interacting proteins that play a role during otic development. We review our transcriptomic, yeast 2-hybrid, and proteomic approaches that have revealed a large number of new candidates. We also discuss how we have begun to identify how Six1 and co-factors interact to direct developmental events necessary for normal otic development.
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Affiliation(s)
- Scott J. Neal
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Anindita Rajasekaran
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Nisveta Jusić
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Louis Taylor
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Mai Read
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Dominique Alfandari
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Francesca Pignoni
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY, USA
| | - Sally A. Moody
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
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2
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Ismail T, Lee HK, Lee H, Kim Y, Kim E, Lee JY, Kim KB, Ryu HY, Cho DH, Kwon TK, Park TJ, Kwon T, Lee HS. Early life exposure to perfluorooctanesulfonate (PFOS) impacts vital biological processes in Xenopus laevis: Integrated morphometric and transcriptomic analyses. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 269:115820. [PMID: 38103469 DOI: 10.1016/j.ecoenv.2023.115820] [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: 08/25/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/19/2023]
Abstract
Perfluorooctanesulfonate (PFOS) is a ubiquitous environmental pollutant associated with increasing health concerns and environmental hazards. Toxicological analyses of PFOS exposure are hampered by large interspecies variations and limited studies on the mechanistic details of PFOS-induced toxicity. We investigated the effects of PFOS exposure on Xenopus laevis embryos based on the reported developmental effects in zebrafish. X. laevis was selected to further our understanding of interspecies variation in response to PFOS, and we built upon previous studies by including transcriptomics and an assessment of ciliogenic effects. Midblastula-stage X. laevis embryos were exposed to PFOS using the frog embryo teratogenesis assay Xenopus (FETAX). Results showed teratogenic effects of PFOS in a time- and dose-dependent manner. The morphological abnormalities of skeleton deformities, a small head, and a miscoiled gut were associated with changes in gene expression evidenced by whole-mount in situ hybridization and transcriptomics. The transcriptomic profile of PFOS-exposed embryos indicated the perturbation in the expression of genes associated with cell death, and downregulation in adenosine triphosphate (ATP) biosynthesis. Moreover, we observed the effects of PFOS exposure on cilia development as a reduction in the number of multiciliated cells and changes in the directionality and velocity of the cilia-driven flow. Collectively, these data broaden the molecular understanding of PFOS-induced developmental effects, whereby ciliary dysfunction and disrupted ATP synthesis are implicated as the probable modes of action of embryotoxicity. Furthermore, our findings present a new challenge to understand the links between PFOS-induced developmental toxicity and vital biological processes.
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Affiliation(s)
- Tayaba Ismail
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Hyun-Kyung Lee
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Hongchan Lee
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Youni Kim
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Eunjeong Kim
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jun-Yeong Lee
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Kee-Beom Kim
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Hong-Yeoul Ryu
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Dong-Hyung Cho
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Taeg Kyu Kwon
- Department of Immunology, School of Medicine, Keimyung University, Daegu 42601, Republic of Korea
| | - Tae Joo Park
- Department of Biological Sciences, College of Information-Bio Convergence, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Taejoon Kwon
- Department of Biomedical Engineering, College of Information-Bio Convergence, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Hyun-Shik Lee
- KNU LAMP Research Center, KNU, Institute of Basic Sciences, BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea.
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3
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Nie S. Use of Frogs as a Model to Study the Etiology of HLHS. J Cardiovasc Dev Dis 2023; 10:51. [PMID: 36826547 PMCID: PMC9965361 DOI: 10.3390/jcdd10020051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
A frog is a classical model organism used to uncover processes and regulations of early vertebrate development, including heart development. Recently, we showed that a frog also represents a useful model to study a rare human congenital heart disease, hypoplastic left heart syndrome. In this review, we first summarized the cellular events and molecular regulations of vertebrate heart development, and the benefit of using a frog model to study congenital heart diseases. Next, we described the challenges in elucidating the etiology of hypoplastic left heart syndrome and discussed how a frog model may contribute to our understanding of the molecular and cellular bases of the disease. We concluded that a frog model offers its unique advantage in uncovering the cellular mechanisms of hypoplastic left heart syndrome; however, combining multiple model organisms, including frogs, is needed to gain a comprehensive understanding of the disease.
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Affiliation(s)
- Shuyi Nie
- School of Biological Sciences, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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4
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Cerrizuela S, Vega-Lopez GA, Méndez-Maldonado K, Velasco I, Aybar MJ. The crucial role of model systems in understanding the complexity of cell signaling in human neurocristopathies. WIREs Mech Dis 2022; 14:e1537. [PMID: 35023327 DOI: 10.1002/wsbm.1537] [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: 03/30/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 11/07/2022]
Abstract
Animal models are useful to study the molecular, cellular, and morphogenetic mechanisms underlying normal and pathological development. Cell-based study models have emerged as an alternative approach to study many aspects of human embryonic development and disease. The neural crest (NC) is a transient, multipotent, and migratory embryonic cell population that generates a diverse group of cell types that arises during vertebrate development. The abnormal formation or development of the NC results in neurocristopathies (NCPs), which are characterized by a broad spectrum of functional and morphological alterations. The impaired molecular mechanisms that give rise to these multiphenotypic diseases are not entirely clear yet. This fact, added to the high incidence of these disorders in the newborn population, has led to the development of systematic approaches for their understanding. In this article, we have systematically reviewed the ways in which experimentation with different animal and cell model systems has improved our knowledge of NCPs, and how these advances might contribute to the development of better diagnostic and therapeutic tools for the treatment of these pathologies. This article is categorized under: Congenital Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Stem Cells and Development Congenital Diseases > Molecular and Cellular Physiology Neurological Diseases > Genetics/Genomics/Epigenetics.
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Affiliation(s)
- Santiago Cerrizuela
- Division of Molecular Neurobiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.,Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), Tucumán, Argentina
| | - Guillermo A Vega-Lopez
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), Tucumán, Argentina.,Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Karla Méndez-Maldonado
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.,Departamento de Fisiología y Farmacología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Iván Velasco
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.,Laboratorio de Reprogramación Celular del Instituto de Fisiología Celular, UNAM en el Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Ciudad de México, Mexico
| | - Manuel J Aybar
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), Tucumán, Argentina.,Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Tucumán, Argentina
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5
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Abstract
Congenital birth defects result from an abnormal development of an embryo and have detrimental effects on children's health. Specifically, congenital heart malformations are a leading cause of death among pediatric patients and often require surgical interventions within the first year of life. Increased efforts to navigate the human genome provide an opportunity to discover multiple candidate genes in patients suffering from birth defects. These efforts, however, fail to provide an explanation regarding the mechanisms of disease pathogenesis and emphasize the need for an efficient platform to screen candidate genes. Xenopus is a rapid, cost effective, high-throughput vertebrate organism to model the mechanisms behind human disease. This review provides numerous examples describing the successful use of Xenopus to investigate the contribution of patient mutations to complex phenotypes including congenital heart disease and heterotaxy. Moreover, we describe a variety of unique methods that allow us to rapidly recapitulate patients' phenotypes in frogs: gene knockout and knockdown strategies, the use of fate maps for targeted manipulations, and novel imaging modalities. The combination of patient genomics data and the functional studies in Xenopus will provide necessary answers to the patients suffering from birth defects. Furthermore, it will allow for the development of better diagnostic methods to ensure early detection and intervention. Finally, with better understanding of disease pathogenesis, new treatment methods can be tailored specifically to address patient's phenotype and genotype.
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Affiliation(s)
- Valentyna Kostiuk
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, United States
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT, United States.
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6
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Harding P, Cunha DL, Moosajee M. Animal and cellular models of microphthalmia. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:2633004021997447. [PMID: 37181112 PMCID: PMC10032472 DOI: 10.1177/2633004021997447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/02/2021] [Indexed: 05/16/2023]
Abstract
Microphthalmia is a rare developmental eye disorder affecting 1 in 7000 births. It is defined as a small (axial length ⩾2 standard deviations below the age-adjusted mean) underdeveloped eye, caused by disruption of ocular development through genetic or environmental factors in the first trimester of pregnancy. Clinical phenotypic heterogeneity exists amongst patients with varying levels of severity, and associated ocular and systemic features. Up to 11% of blind children are reported to have microphthalmia, yet currently no treatments are available. By identifying the aetiology of microphthalmia and understanding how the mechanisms of eye development are disrupted, we can gain a better understanding of the pathogenesis. Animal models, mainly mouse, zebrafish and Xenopus, have provided extensive information on the genetic regulation of oculogenesis, and how perturbation of these pathways leads to microphthalmia. However, differences exist between species, hence cellular models, such as patient-derived induced pluripotent stem cell (iPSC) optic vesicles, are now being used to provide greater insights into the human disease process. Progress in 3D cellular modelling techniques has enhanced the ability of researchers to study interactions of different cell types during eye development. Through improved molecular knowledge of microphthalmia, preventative or postnatal therapies may be developed, together with establishing genotype-phenotype correlations in order to provide patients with the appropriate prognosis, multidisciplinary care and informed genetic counselling. This review summarises some key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future. Plain language summary Animal and Cellular Models of the Eye Disorder, Microphthalmia (Small Eye) Microphthalmia, meaning a small, underdeveloped eye, is a rare disorder that children are born with. Genetic changes or variations in the environment during the first 3 months of pregnancy can disrupt early development of the eye, resulting in microphthalmia. Up to 11% of blind children have microphthalmia, yet currently no treatments are available. By understanding the genes necessary for eye development, we can determine how disruption by genetic changes or environmental factors can cause this condition. This helps us understand why microphthalmia occurs, and ensure patients are provided with the appropriate clinical care and genetic counselling advice. Additionally, by understanding the causes of microphthalmia, researchers can develop treatments to prevent or reduce the severity of this condition. Animal models, particularly mice, zebrafish and frogs, which can also develop small eyes due to the same genetic/environmental changes, have helped us understand the genes which are important for eye development and can cause birth eye defects when disrupted. Studying a patient's own cells grown in the laboratory can further help researchers understand how changes in genes affect their function. Both animal and cellular models can be used to develop and test new drugs, which could provide treatment options for patients living with microphthalmia. This review summarises the key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future.
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Affiliation(s)
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, 11-43 Bath
Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Foundation Trust, London, UK
- The Francis Crick Institute, London, UK
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7
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Effects of Ferrocenyl 4-(Imino)-1,4-Dihydro-quinolines on Xenopus laevis Prophase I - Arrested Oocytes: Survival and Hormonal-Induced M-Phase Entry. Int J Mol Sci 2020; 21:ijms21093049. [PMID: 32357477 PMCID: PMC7246863 DOI: 10.3390/ijms21093049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 01/14/2023] Open
Abstract
Xenopus oocytes were used as cellular and molecular sentinels to assess the effects of a new class of organometallic compounds called ferrocenyl dihydroquinolines that have been developed as potential anti-cancer agents. One ferrocenyl dihydroquinoline compound exerted deleterious effects on oocyte survival after 48 h of incubation at 100 μM. Two ferrocenyl dihydroquinoline compounds had an inhibitory effect on the resumption of progesterone induced oocyte meiosis, compared to controls without ferrocenyl groups. In these inhibited oocytes, no MPF (Cdk1/cyclin B) activity was detected by western blot analysis as shown by the lack of phosphorylation of histone H3. The dephosphorylation of the inhibitory Y15 residue of Cdk1 occurred but cyclin B was degraded. Moreover, two apoptotic death markers, the active caspase 3 and the phosphorylated histone H2, were detected. Only 7-chloro-1-ferrocenylmethyl-4-(phenylylimino)-1,4-dihydroquinoline (8) did not show any toxicity and allowed the assembly of a histologically normal metaphase II meiotic spindle while inhibiting the proliferation of cancer cell lines with a low IC50, suggesting that this compound appears suitable as an antimitotic agent.
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8
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Sato K, Tokmakov AA. Toward the understanding of biology of oocyte life cycle in Xenopus Laevis: No oocytes left behind. Reprod Med Biol 2020; 19:114-119. [PMID: 32273815 PMCID: PMC7138939 DOI: 10.1002/rmb2.12314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 12/09/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND For the past more than 25 years, we have been focusing on the developmental and reproductive biology of the female gametes, oocytes, and eggs, of the African clawed frog Xenopus laevis. METHODS The events associated with the life cycle of these cells can be classified into the four main categories: first, oogenesis and cell growth in the ovary during the first meiotic arrest; second, maturation and ovulation that occur simultaneously and result in the acquisition of fertilization competence and the second meiotic arrest; third, fertilization, that is sperm-induced transition from egg to zygote; and fourth, egg death after spontaneous activation in the absence of fertilizing sperm. MAIN FINDINGS Our studies have demonstrated that signal transduction system involving tyrosine kinase Src and other oocyte/egg membrane-associated molecules such as uroplakin III and some other cytoplasmic proteins such as mitogen-activated protein kinase (MAPK) play important roles for successful ovulation, maturation, fertilization, and initiation of embryonic development. CONCLUSION We summarize recent advances in understanding cellular and molecular mechanisms underlying life cycle events of the oocytes and eggs. Our further intention is to discuss and predict potentially promising impact of the recent findings on the challenges facing reproductive biology and medicine, as well as societal contexts.
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Affiliation(s)
- Ken‐ichi Sato
- Laboratory of Cell Signaling and DevelopmentDepartment of Industrial Life SciencesFaculty of Life SciencesKyoto Sangyo UniversityKyotoJapan
| | - Alexander A. Tokmakov
- Laboratory of Cell Signaling and DevelopmentDepartment of Industrial Life SciencesFaculty of Life SciencesKyoto Sangyo UniversityKyotoJapan
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9
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Deniz E, Jonas S, Khokha MK, Choma MA. Quantitative Phenotyping of Xenopus Embryonic Heart Pathophysiology Using Hemoglobin Contrast Subtraction Angiography to Screen Human Cardiomyopathies. Front Physiol 2019; 10:1197. [PMID: 31620018 PMCID: PMC6763566 DOI: 10.3389/fphys.2019.01197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 09/03/2019] [Indexed: 01/09/2023] Open
Abstract
Congenital heart disease (CHD) is a significant cause of mortality in infants and adults. Currently human genomic analysis has identified a number of candidate genes in these patients. These genes span diverse categories of gene function suggesting that despite the similarity in cardiac lesion, the underlying pathophysiology may be different. In fact, patients with similar CHDs can have drastically different outcomes, including a dramatic decrease in myocardial function. To test these human candidate genes for their impact on myocardial function, we need efficient animals models of disease. For this purpose, we paired Xenopus tropicalis with our microangiography technique, hemoglobin contrast subtraction angiography (HCSA). To demonstrate the gene-teratogen-physiology relationship, we modeled human cardiomyopathy in tadpoles. First we depleted the sarcomeric protein myosin heavy chain 6 (myh6) expression using morpholino oligos. Next, we exposed developing embryos to the teratogen ethanol and in both conditions showed varying degrees of cardiac dysfunction. Our results demonstrate that HCSA can distinguish biomechanical phenotypes in the context of gene dysfunction or teratogen. This approach can be used to screen numerous candidate CHD genes or suspected teratogens for their effect on cardiac function.
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Affiliation(s)
- Engin Deniz
- Department of Pediatrics, Yale University, New Haven, CT, United States
| | - Stephan Jonas
- Department of Informatics, Technical University of Munich, Munich, Germany
| | - Mustafa K Khokha
- Department of Pediatrics, Yale University, New Haven, CT, United States.,Department of Genetics, Yale University, New Haven, CT, United States
| | - Michael A Choma
- Department of Pediatrics, Yale University, New Haven, CT, United States.,Department of Diagnostic Radiology, Yale University, New Haven, CT, United States.,Department of Biomedical Engineering, Yale University, New Haven, CT, United States.,Department of Applied Physics, Yale University, New Haven, CT, United States
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10
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Mitros T, Lyons JB, Session AM, Jenkins J, Shu S, Kwon T, Lane M, Ng C, Grammer TC, Khokha MK, Grimwood J, Schmutz J, Harland RM, Rokhsar DS. A chromosome-scale genome assembly and dense genetic map for Xenopus tropicalis. Dev Biol 2019; 452:8-20. [PMID: 30980799 DOI: 10.1016/j.ydbio.2019.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 03/12/2019] [Accepted: 03/22/2019] [Indexed: 12/19/2022]
Abstract
The Western clawed frog Xenopus tropicalis is a diploid model system for both frog genetics and developmental biology, complementary to the paleotetraploid X. laevis. Here we report a chromosome-scale assembly of the X. tropicalis genome, improving the previously published draft genome assembly through the use of new assembly algorithms, additional sequence data, and the addition of a dense genetic map. The improved genome enables the mapping of specific traits (e.g., the sex locus or Mendelian mutants) and the characterization of chromosome-scale synteny with other tetrapods. We also report an improved annotation of the genome that integrates deep transcriptome sequence from diverse tissues and stages. The exon-intron structures of these genes are highly conserved relative to both X. laevis and human, as are chromosomal linkages ("synteny") and local gene order. A network analysis of developmental gene expression will aid future studies.
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Affiliation(s)
- Therese Mitros
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA.
| | - Jessica B Lyons
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA.
| | - Adam M Session
- Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA.
| | - Jerry Jenkins
- Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA; HudsonAlpha Institute of Biotechnology, 601 Genome Way, Huntsville, AL 35806, USA.
| | - Shengquiang Shu
- Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA.
| | - Taejoon Kwon
- Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
| | - Maura Lane
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, FMP 410, 333 Cedar St./LCI 305, New Haven, CT 06520, USA.
| | - Connie Ng
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA.
| | - Timothy C Grammer
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA.
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, FMP 410, 333 Cedar St./LCI 305, New Haven, CT 06520, USA.
| | - Jane Grimwood
- Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA; HudsonAlpha Institute of Biotechnology, 601 Genome Way, Huntsville, AL 35806, USA.
| | - Jeremy Schmutz
- Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA; HudsonAlpha Institute of Biotechnology, 601 Genome Way, Huntsville, AL 35806, USA.
| | - Richard M Harland
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA.
| | - Daniel S Rokhsar
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition, Berkeley, CA 94720-3200, USA; Joint Genome Institute, 2800 Mitchell Dr # 100, Walnut Creek, CA 94598, USA; Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 9040495, Japan.
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11
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Tang T, Deniz E, Khokha MK, Tagare HD. Gaussian process post-processing for particle tracking velocimetry. BIOMEDICAL OPTICS EXPRESS 2019; 10:3196-3216. [PMID: 31360598 PMCID: PMC6640822 DOI: 10.1364/boe.10.003196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/14/2019] [Accepted: 05/14/2019] [Indexed: 05/21/2023]
Abstract
Particle tracking velocimetry (PTV) gives quantitative estimates of fluid flow velocities from images. But particle tracking is a complicated problem, and it often produces results that need substantial post-processing. We propose a novel Gaussian process regression-based post-processing step for PTV: The method smooths ("denoises") and densely interpolates velocity estimates while rejecting track irregularities. The method works under a large range of particle densities and fluid velocities. In addition, the method calculates standard deviances (error bars) for the velocity estimates, opening the possibility of propagating the standard deviances through subsequent processing and analysis. The accuracy of the method is experimentally evaluated using Optical Coherence Tomography images of particles in laminar flow in a pipe phantom. Following this, the method is used to quantify cilia-driven fluid flow and vorticity patterns in a developing Xenopus embryo.
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Affiliation(s)
- Tommy Tang
- Department of Radiology and Biomedical Imaging, Yale University, 300 Cedar St, New Haven, CT 06510,
USA
| | - Engin Deniz
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University, 333 Cedar Street, New Haven, CT 06510,
USA
| | - Mustafa K. Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics, Yale University, 333 Cedar Street, New Haven, CT 06510,
USA
- Department of Genetics, Yale University, 333 Cedar Street, New Haven, CT 06510,
USA
| | - Hemant D. Tagare
- Department of Radiology and Biomedical Imaging, Yale University, 300 Cedar St, New Haven, CT 06510,
USA
- Department of {Biomedical Engineering, Electrical Engineering, Statistics and Data Science}, Yale University, New Haven, CT 06510,
USA
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12
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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: 49] [Impact Index Per Article: 9.8] [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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13
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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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14
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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: 89] [Impact Index Per Article: 12.7] [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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15
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An interspecies heart-to-heart: Using Xenopus to uncover the genetic basis of congenital heart disease. CURRENT PATHOBIOLOGY REPORTS 2017; 5:187-196. [PMID: 29082114 DOI: 10.1007/s40139-017-0142-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW Given the enormous impact congenital heart disease has on child health, it is imperative that we improve our understanding of the disease mechanisms that underlie patient phenotypes and clinical outcomes. This review will outline the merits of using the frog model, Xenopus, as a tool to study human cardiac development and left-right patterning mechanisms associated with congenital heart disease. RECENT FINDINGS Patient-driven gene discovery continues to provide new insight into the mechanisms of congenital heart disease, and by extension, patient phenotypes and outcomes. By identifying gene variants in CHD patients, studies in Xenopus have elucidated the molecular mechanisms of how these candidate genes affect cardiac development, both cardiogenesis as well as left-right patterning, which can have a major impact on cardiac morphogenesis. Xenopus has also proved to be a useful screening tool for the biological relevance of identified patient-mutations, and ongoing investigations continue to illuminate disease mechanisms. SUMMARY Analyses in model organisms can help to elucidate the disease mechanisms underlying CHD patient phenotypes. Using Xenopus to disentangle the genotype-phenotype relationships of well-known and novel disease genes could enhance the ability of physicians to efficaciously treat patients and predict clinical outcomes, ultimately improving quality of life and survival rates of patients born with congenital heart disease.
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Delos Santos N, Azmat S, Cuenca Y, Drenth J, Lauper J, Tseng AS. Effects of the biocide methylisothiazolinone on Xenopus laevis wound healing and tail regeneration. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 181:37-45. [PMID: 27810491 DOI: 10.1016/j.aquatox.2016.10.016] [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: 08/09/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
The South African clawed frog, Xenopus laevis, has a strong history as a suitable model for environmental studies. Its embryos and transparent tadpoles are highly sensitive to the environment and their developmental processes are well described. It is also amenable for molecular studies. These characteristics enable its use for rapid identification and understanding of exposure-induced defects. To investigate the consequences of chemical exposure on aquatic animals, Xenopus laevis embryos and tadpoles were exposed to the biocide, methylisothiazolinone (MIT). Frog tadpoles exposed to MIT following tail amputation lost their natural regenerative ability. This inhibition of regeneration led to a failure to regrow tissues including the spinal cord, muscle, and notochord. This MIT-dependent regenerative defect is due to a failure to close the amputation wound. A wound healing assay revealed that while untreated embryos close their wounds within one day after injury, MIT-treated animals maintained open wounds that did not reduce in size and caused lethality. Concomitant exposure of MIT with chemicals containing thiol groups such as glutathione and N-acetyl cysteine restored normal wound healing and regeneration responses in tadpoles. Together these results indicate that exposure to MIT impairs developmental wound repair and tissue regeneration in Xenopus laevis. Thus, this study reveals new aspects of MIT activity and demonstrates that Xenopus laevis is a well-suited model for facilitating future research into chemical exposure effects on injury responses.
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Affiliation(s)
- Nicole Delos Santos
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Summer Azmat
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Yesenia Cuenca
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Jessica Drenth
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Julia Lauper
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Ai-Sun Tseng
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA.
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17
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Shigeta M, Sakane Y, Iida M, Suzuki M, Kashiwagi K, Kashiwagi A, Fujii S, Yamamoto T, Suzuki KIT. Rapid and efficient analysis of gene function using CRISPR-Cas9 inXenopus tropicalisfounders. Genes Cells 2016; 21:755-71. [DOI: 10.1111/gtc.12379] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 04/22/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Mitsuki Shigeta
- Department of Mathematical and Life Sciences; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Yuto Sakane
- Department of Mathematical and Life Sciences; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Midori Iida
- Department of Bioscience and Bioinformatics; Kyushu Institute of Technology; 680-4 Kawazu Iizuka Fukuoka 820-8502 Japan
| | - Miyuki Suzuki
- Department of Mathematical and Life Sciences; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Keiko Kashiwagi
- Institute for Amphibian Biology; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Akihiko Kashiwagi
- Institute for Amphibian Biology; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Satoshi Fujii
- Department of Bioscience and Bioinformatics; Kyushu Institute of Technology; 680-4 Kawazu Iizuka Fukuoka 820-8502 Japan
| | - Takashi Yamamoto
- Department of Mathematical and Life Sciences; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Ken-ichi T. Suzuki
- Department of Mathematical and Life Sciences; Hiroshima University; 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8526 Japan
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18
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Haynes-Gimore N, Banach M, Brown E, Dawes R, Edholm ES, Kim M, Robert J. Semi-solid tumor model in Xenopus laevis/gilli cloned tadpoles for intravital study of neovascularization, immune cells and melanophore infiltration. Dev Biol 2015; 408:205-12. [PMID: 25601449 PMCID: PMC4506265 DOI: 10.1016/j.ydbio.2015.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/29/2014] [Accepted: 01/08/2015] [Indexed: 11/18/2022]
Abstract
Tumors have the ability to grow as a self-sustaining entity within the body. This autonomy is in part accomplished by the tumor cells ability to induce the formation of new blood vessels (angiogenesis) and by controlling cell trafficking inside the tumor mass. These abilities greatly reduce the efficacy of many cancer therapies and pose challenges for the development of more effective cancer treatments. Hence, there is a need for animal models suitable for direct microscopy observation of blood vessel formation and cell trafficking, especially during early stages of tumor establishment. Here, we have developed a reliable and cost effective tumor model system in tadpoles of the amphibian Xenopus laevis. Tadpoles are ideally suited for direct microscopy observation because of their small size and transparency. Using the thymic lymphoid tumor line 15/0 derived from, and transplantable into, the X. laevis/gilli isogenic clone LG-15, we have adapted a system that consists in transplanting 15/0 tumor cells embedded into rat collagen under the dorsal skin of LG-15 tadpole recipients. This system recapitulates many facets of mammalian tumorigenesis and permits real time visualization of the active formation of the tumor microenvironment induced by 15/0 tumor cells including neovascularization, collagen rearrangements as well as infiltration of immune cells and melanophores.
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Affiliation(s)
- Nikesha Haynes-Gimore
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA; Department of Pathology, University of Rochester Medical Center, Rochester, USA
| | - Maureen Banach
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Edward Brown
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, USA
| | - Ryan Dawes
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, USA
| | - Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Minsoo Kim
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA; Center for Vaccine Biology and Immunology, Rochester, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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19
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Moody SA, Neilson KM, Kenyon KL, Alfandari D, Pignoni F. Using Xenopus to discover new genes involved in branchiootorenal spectrum disorders. Comp Biochem Physiol C Toxicol Pharmacol 2015; 178:16-24. [PMID: 26117063 PMCID: PMC4662879 DOI: 10.1016/j.cbpc.2015.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 12/14/2022]
Abstract
Congenital hearing loss is an important clinical problem because, without early intervention, affected children do not properly acquire language and consequently have difficulties developing social skills. Although most newborns in the US are screened for hearing deficits, even earlier diagnosis can be made with prenatal genetic screening. Genetic screening that identifies the relevant mutated gene can also warn about potential congenital defects in organs not related to hearing. We will discuss efforts to identify new candidate genes that underlie the Branchiootorenal spectrum disorders in which affected children have hearing deficits and are also at risk for kidney defects. Mutations in two genes, SIX1 and EYA1, have been identified in about half of the patients tested. To uncover new candidate genes, we have used the aquatic animal model, Xenopus laevis, to identify genes that are part of the developmental genetic pathway of Six1 during otic and kidney development. We have already identified a large number of potential Six1 transcriptional targets and candidate co-factor proteins that are expressed at the right time and in the correct tissues to interact with Six1 during development. We discuss the advantages of using this system for gene discovery in a human congenital hearing loss syndrome.
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Affiliation(s)
- Sally A Moody
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA.
| | - Karen M Neilson
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
| | - Kristy L Kenyon
- Department of Biology, Hobart and William Smith Colleges, Geneva, NY, USA
| | - Dominique Alfandari
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Francesca Pignoni
- Department of Ophthalmology, Upstate Medical University, Syracuse, NY, USA
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20
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Ramírez-Gordillo D, Powers TR, van Velkinburgh JC, Trujillo-Provencio C, Schilkey F, Serrano EE. RNA-Seq and microarray analysis of the Xenopus inner ear transcriptome discloses orthologous OMIM(®) genes for hereditary disorders of hearing and balance. BMC Res Notes 2015; 8:691. [PMID: 26582541 PMCID: PMC4652436 DOI: 10.1186/s13104-015-1485-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/21/2015] [Indexed: 12/14/2022] Open
Abstract
Background Auditory and vestibular disorders are prevalent sensory disabilities caused by genetic and environmental (noise, trauma, chemicals) factors that often damage mechanosensory hair cells of the inner ear. Development of treatments for inner ear disorders of hearing and balance relies on the use of animal models such as fish, amphibians, reptiles, birds, and non-human mammals. Here, we aimed to augment the utility of the genus Xenopus for uncovering genetic mechanisms essential for the maintenance of inner ear structure and function. Results Using Affymetrix GeneChip®X. laevis Genome 2.0 Arrays and Illumina-Solexa sequencing methods, we determined that the transcriptional profile of the Xenopuslaevis inner ear comprises hundreds of genes that are orthologous to OMIM® genes implicated in deafness and vestibular disorders in humans. Analysis of genes that mapped to both technologies demonstrated that, with our methods, a combination of microarray and RNA-Seq detected expression of more genes than either platform alone. Conclusions As part of this study we identified candidate scaffold regions of the Xenopus tropicalis genome that can be used to investigate hearing and balance using genetic and informatics procedures that are available through the National Xenopus Resource (NXR), and the open access data repository, Xenbase. The results and approaches presented here expand the viability of Xenopus as an animal model for inner ear research. Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1485-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - TuShun R Powers
- Biology Department, New Mexico State University (NMSU), Las Cruces, NM, 88003, USA.
| | | | | | - Faye Schilkey
- National Center for Genome Resources (NCGR), Santa Fe, NM, 87505, USA.
| | - Elba E Serrano
- Biology Department, New Mexico State University (NMSU), Las Cruces, NM, 88003, USA.
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21
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Xenopus laevis oocyte maturation is affected by metal chlorides. Toxicol In Vitro 2015; 29:1124-31. [DOI: 10.1016/j.tiv.2015.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 04/20/2015] [Accepted: 04/22/2015] [Indexed: 02/02/2023]
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22
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Shrestha B, Sripadi P, Reschke BR, Henderson HD, Powell MJ, Moody SA, Vertes A. Subcellular metabolite and lipid analysis of Xenopus laevis eggs by LAESI mass spectrometry. PLoS One 2014; 9:e115173. [PMID: 25506922 PMCID: PMC4266676 DOI: 10.1371/journal.pone.0115173] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/19/2014] [Indexed: 01/04/2023] Open
Abstract
Xenopus laevis eggs are used as a biological model system for studying fertilization and early embryonic development in vertebrates. Most methods used for their molecular analysis require elaborate sample preparation including separate protocols for the water soluble and lipid components. In this study, laser ablation electrospray ionization (LAESI), an ambient ionization technique, was used for direct mass spectrometric analysis of X. laevis eggs and early stage embryos up to five cleavage cycles. Single unfertilized and fertilized eggs, their animal and vegetal poles, and embryos through the 32-cell stage were analyzed. Fifty two small metabolite ions, including glutathione, GABA and amino acids, as well as numerous lipids including 14 fatty acids, 13 lysophosphatidylcholines, 36 phosphatidylcholines and 29 triacylglycerols were putatively identified. Additionally, some proteins, for example thymosin β4 (Xen), were also detected. On the subcellular level, the lipid profiles were found to differ between the animal and vegetal poles of the eggs. Radial profiling revealed profound compositional differences between the jelly coat vitelline/plasma membrane and egg cytoplasm. Changes in the metabolic profile of the egg following fertilization, e.g., the decline of polyamine content with the development of the embryo were observed using LAESI-MS. This approach enables the exploration of metabolic and lipid changes during the early stages of embryogenesis.
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Affiliation(s)
- Bindesh Shrestha
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
| | - Prabhakar Sripadi
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
| | - Brent R. Reschke
- Protea Biosciences, Morgantown, West Virginia, United States of America
| | | | - Matthew J. Powell
- Protea Biosciences, Morgantown, West Virginia, United States of America
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, The George Washington University, Washington, D.C., United States of America
| | - Akos Vertes
- Department of Chemistry, W. M. Keck Institute for Proteomics Technology and Applications, The George Washington University, Washington, D.C., United States of America
- * E-mail:
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23
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Watson FL, Schmidt H, Turman ZK, Hole N, Garcia H, Gregg J, Tilghman J, Fradinger EA. Organophosphate pesticides induce morphological abnormalities and decrease locomotor activity and heart rate in Danio rerio and Xenopus laevis. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:1337-1345. [PMID: 24677261 DOI: 10.1002/etc.2559] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/23/2013] [Accepted: 02/16/2014] [Indexed: 06/03/2023]
Abstract
Organophosphate pesticides (OPs), a class of acetylcholinesterase inhibitors, are used widely in agriculture to reduce insect populations. Because of the conservation of acetylcholinesterase between invertebrates and vertebrates, OPs also can adversely affect nontarget species, such as aquatic and terrestrial animals. This study used uniform conditions to analyze the morphological and physiological effects caused by developmental exposure to 3 commonly used OPs-chlorpyrifos, dichlorvos, and diazinon-on 2 aquatic vertebrate species, Danio rerio (zebrafish) and Xenopus laevis. Survival, locomotor activity, heart rate, and gross anatomical abnormalities, including kyphosis and edema, were observed over a 5-d period in response to OP concentrations ranging from 0 µM to 1000 µM. Both zebrafish and Xenopus showed decreased survival for all 3 OPs at higher concentrations. However, Xenopus showed higher mortality than zebrafish at lower chlorpyrifos and dichlorvos concentrations. Both models showed a dose-dependent decrease in heart rate and free-swimming larval activity in response to chlorpyrifos and dichlorvos. In addition, kyphosis and decreased spine length were prominent in Xenopus in response to 10 µM of chlorpyrifos and 0.1 µM dichlorvos. Although diazinon induced no effects on skeletal and cardiac motor activity in either species, it did induce cardiac edemas in zebrafish. Differences in the biological actions of OPs and their differential effects in these 2 vertebrate models demonstrate the importance of using common protocols and multiple models to evaluate the ecotoxicology of OPs.
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Affiliation(s)
- Fiona L Watson
- Department of Biology, Washington and Lee University, Lexington, Virginia, USA
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24
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Tahir R, Kennedy A, Elsea SH, Dickinson AJ. Retinoic acid induced-1 (Rai1) regulates craniofacial and brain development in Xenopus. Mech Dev 2014; 133:91-104. [PMID: 24878353 DOI: 10.1016/j.mod.2014.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 12/18/2022]
Abstract
Retinoic acid induced-1 (RAI1) is an important yet understudied histone code reader that when mutated in humans results in Smith-Magenis syndrome (SMS), a neurobehavioral disorder accompanied by signature craniofacial abnormalities. Despite previous studies in mouse and human cell models, very little is known about the function of RAI1 during embryonic development. In the present study, we have turned to the model vertebrates Xenopus laevis and Xenopus tropicalis to better understand the developmental roles of Rai1. First we demonstrate that the Rai1 protein sequence is conserved in frogs, especially in known functional domains. By in situ hybridization we revealed expression of rai1 in the developing craniofacial tissues and the nervous system. Knockdown of Rai1 using antisense morpholinos resulted in defects in the developing brain and face. In particular, Rai1 morphants display midface hypoplasia and malformed mouth shape analogous to defects in humans with SMS. These craniofacial defects were accompanied with aberrant neural crest migration and reduction in the size of facial cartilage elements. Rai1 morphants also had defects in axon patterns and decreased forebrain ventricle size. Such brain defects correlated with a decrease in the neurotrophic factor, bdnf, and increased forebrain apoptosis. Our results emphasize a critical role of Rai1 for normal neural and craniofacial development, and further the current understanding of potential mechanisms that cause SMS.
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Affiliation(s)
- Raiha Tahir
- Center of the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Allyson Kennedy
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB2015, Houston, TX 77030, USA
| | - Amanda J Dickinson
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA.
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Schmitt SM, Gull M, Brändli AW. Engineering Xenopus embryos for phenotypic drug discovery screening. Adv Drug Deliv Rev 2014; 69-70:225-46. [PMID: 24576445 DOI: 10.1016/j.addr.2014.02.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 02/08/2023]
Abstract
Many rare human inherited diseases remain untreatable despite the fact that the disease causing genes are known and adequate mouse disease models have been developed. In vivo phenotypic drug screening relies on isolating drug candidates by their ability to produce a desired therapeutic phenotype in whole organisms. Embryos of zebrafish and Xenopus frogs are abundant, small and free-living. They can be easily arrayed in multi-well dishes and treated with small organic molecules. With the development of novel genome modification tools, such a zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and CRISPR/Cas, it is now possible to efficiently engineer non-mammalian models of inherited human diseases. Here, we will review the rapid progress made in adapting these novel genome editing tools to Xenopus. The advantages of Xenopus embryos as in vivo models to study human inherited diseases will be presented and their utility for drug discovery screening will be discussed. Being a tetrapod, Xenopus complements zebrafish as an indispensable non-mammalian animal model for the study of human disease pathologies and the discovery of novel therapeutics for inherited diseases.
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A potential molecular pathogenesis of cardiac/laterality defects in Oculo-Facio-Cardio-Dental syndrome. Dev Biol 2014; 387:28-36. [PMID: 24440151 DOI: 10.1016/j.ydbio.2014.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/04/2014] [Accepted: 01/09/2014] [Indexed: 01/16/2023]
Abstract
Pitx2 is the last effector of the left-right (LR) cascade known to date and plays a crucial role in the patterning of LR asymmetry. In Xenopus embryos, the expression of Pitx2 gene in the left lateral plate mesoderm (LPM) is directly regulated by Xnr1 signaling, which is mediated by Smads and FoxH1. Previous studies suggest that the suppression of Pitx2 gene in the left LPM is a potential cause of cardiac/laterality defects in Oculo-Facio-Cardio-Dental (OFCD) syndrome, which is known to be caused by mutations in BCL6 co-repressor (BCOR) gene. Recently, our work has revealed that the BCL6/BCOR complex blocks Notch-dependent transcriptional activity to protect the expression of Pitx2 in the left LPM from the inhibitory activity of Notch signaling. These studies indicated that uncontrolled Notch activity in the left LPM caused by dysfunction of BCOR may result in cardiac/laterality defects of OFCD syndrome. However, this Notch-dependent inhibitory mechanism of Pitx2 gene transcription still remains unknown. Here we report that transcriptional repressor ESR1, which acts downstream of Notch signaling, inhibits the expression of Pitx2 gene by binding to a left side-specific enhancer (ASE) region in Pitx2 gene and recruiting histone deacetylase 1 (HDAC1) to this region. Once HDAC1 is tethered, histone acetyltransferase p300 is no longer recruited to the Xnr1-dependent transcriptional complex on the ASE region, leading to the suppression of Pitx2 gene in the left LPM. The study presented here uncovers the regulatory mechanism of Pitx2 gene transcription which may contribute to an understanding of pathogenesis of OFCD syndrome.
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27
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Haslam IS, Roubos EW, Mangoni ML, Yoshizato K, Vaudry H, Kloepper JE, Pattwell DM, Maderson PFA, Paus R. From frog integument to human skin: dermatological perspectives from frog skin biology. Biol Rev Camb Philos Soc 2013; 89:618-55. [DOI: 10.1111/brv.12072] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 10/03/2013] [Accepted: 10/22/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Iain S. Haslam
- The Dermatology Centre, Salford Royal NHS Foundation Trust, Institute of Inflammation and Repair; University of Manchester; Oxford Road Manchester M13 9PT U.K
| | - Eric W. Roubos
- Department of Anatomy; Radboud University Medical Centre; Geert Grooteplein Noord 2, 6525 EZ, Nijmegen P.O. Box 9101, 6500 HB Nijmegen The Netherlands
| | - Maria Luisa Mangoni
- Department of Biochemical Sciences, Istituto Pasteur-Fondazione Cenci Bolognetti; La Sapienza University of Rome, Piazzale Aldo Moro, 5-00185; Rome Italy
| | - Katsutoshi Yoshizato
- Academic Advisors Office, Synthetic Biology Research Center; Osaka City University Graduate School of Medicine; Osaka Japan
- Phoenixbio Co. Ltd; 3-4-1, Kagamiyama; Higashihiroshima Hiroshima 739-0046 Japan
| | - Hubert Vaudry
- European Institute for Peptide Research; University of Rouen; Mont-Saint-Aignan Place Emile Blondel 76821 France
- INSERM U-982, CNRS; University of Rouen; Mont-Saint-Aignan Place Emile Blondel 76821 France
| | - Jennifer E. Kloepper
- Klinik für Dermatologie, Allergologie und Venerologie; Universitätsklinikum Schleswig-Holstein, Ratzeburger Allee 160; 23538 Lübeck Germany
| | - David M. Pattwell
- Leahurst Campus, Institute of Learning & Teaching; School of Veterinary Science, University of Liverpool; Neston CH64 7TE U.K
| | | | - Ralf Paus
- The Dermatology Centre, Salford Royal NHS Foundation Trust, Institute of Inflammation and Repair; University of Manchester; Oxford Road Manchester M13 9PT U.K
- Klinik für Dermatologie, Allergologie und Venerologie; Universitätsklinikum Schleswig-Holstein, Ratzeburger Allee 160; 23538 Lübeck Germany
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28
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Segerdell E, Ponferrada VG, James-Zorn C, Burns KA, Fortriede JD, Dahdul WM, Vize PD, Zorn AM. Enhanced XAO: the ontology of Xenopus anatomy and development underpins more accurate annotation of gene expression and queries on Xenbase. J Biomed Semantics 2013; 4:31. [PMID: 24139024 PMCID: PMC3816597 DOI: 10.1186/2041-1480-4-31] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 10/11/2013] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The African clawed frogs Xenopus laevis and Xenopus tropicalis are prominent animal model organisms. Xenopus research contributes to the understanding of genetic, developmental and molecular mechanisms underlying human disease. The Xenopus Anatomy Ontology (XAO) reflects the anatomy and embryological development of Xenopus. The XAO provides consistent terminology that can be applied to anatomical feature descriptions along with a set of relationships that indicate how each anatomical entity is related to others in the embryo, tadpole, or adult frog. The XAO is integral to the functionality of Xenbase (http://www.xenbase.org), the Xenopus model organism database. RESULTS We significantly expanded the XAO in the last five years by adding 612 anatomical terms, 2934 relationships between them, 640 synonyms, and 547 ontology cross-references. Each term now has a definition, so database users and curators can be certain they are selecting the correct term when specifying an anatomical entity. With developmental timing information now asserted for every anatomical term, the ontology provides internal checks that ensure high-quality gene expression and phenotype data annotation. The XAO, now with 1313 defined anatomical and developmental stage terms, has been integrated with Xenbase expression and anatomy term searches and it enables links between various data types including images, clones, and publications. Improvements to the XAO structure and anatomical definitions have also enhanced cross-references to anatomy ontologies of other model organisms and humans, providing a bridge between Xenopus data and other vertebrates. The ontology is free and open to all users. CONCLUSIONS The expanded and improved XAO allows enhanced capture of Xenopus research data and aids mechanisms for performing complex retrieval and analysis of gene expression, phenotypes, and antibodies through text-matching and manual curation. Its comprehensive references to ontologies across taxa help integrate these data for human disease modeling.
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Affiliation(s)
- Erik Segerdell
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Virgilio G Ponferrada
- Division of Developmental Biology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA
| | - Christina James-Zorn
- Division of Developmental Biology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA
| | - Kevin A Burns
- Division of Developmental Biology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA
| | - Joshua D Fortriede
- Division of Developmental Biology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA
| | - Wasila M Dahdul
- Department of Biology, University of South Dakota, Vermillion, SD, USA
- National Evolutionary Synthesis Center, Durham, NC, USA
| | - Peter D Vize
- Department of Biological Science, University of Calgary, Calgary, AB, Canada
| | - Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children’s Research Foundation, Cincinnati, OH, USA
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Liu C, Xia X, Sun L, Luan X, Jin Y, Liu L. Female hormone release of microencapsulated Xenopus laevis ovarian cells. Int J Pharm 2013; 450:177-84. [PMID: 23623793 DOI: 10.1016/j.ijpharm.2013.04.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/25/2013] [Accepted: 04/09/2013] [Indexed: 01/28/2023]
Abstract
Cell microencapsulation has potential for the treatment of endocrine diseases. This study aims to probe the feasibility of Xenopus laevis as an animal model for cell microencapsulation and transplantation and to evaluate the female hormone release of microencapsulated X. laevis ovarian cells. The cells were harvested, cultured and microencapsulated into alginate-chitosan-alginate microcapsules with an electrostatic generator. The estradiol and progesterone releases of the microencapsulated X. laevis ovarian cells were investigated both in vitro and in vivo. The results showed that the microencapsulated cells kept secreting estradiol and progesterone in vitro for 60 days. After transplantation, serum estradiol and progesterone levels in ovariectomized X. laevis remained elevated for 60 days. X. laevis has been proved to be a suitable animal model for cell microencapsulation and transplantation. Microencapsulated ovarian cells may be considered as a promising endogenous drug delivery system for the treatment of deficiency of female hormones.
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Affiliation(s)
- Cong Liu
- Zhejiang University, Institute of Pharmaceutics, Hangzhou 310058, PR China
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del Viso F, Bhattacharya D, Kong Y, Gilchrist MJ, Khokha MK. Exon capture and bulk segregant analysis: rapid discovery of causative mutations using high-throughput sequencing. BMC Genomics 2012; 13:649. [PMID: 23171430 PMCID: PMC3526394 DOI: 10.1186/1471-2164-13-649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/15/2012] [Indexed: 11/21/2022] Open
Abstract
Background Exome sequencing has transformed human genetic analysis and may do the same for other vertebrate model systems. However, a major challenge is sifting through the large number of sequence variants to identify the causative mutation for a given phenotype. In models like Xenopus tropicalis, an incomplete and occasionally incorrect genome assembly compounds this problem. To facilitate cloning of X. tropicalis mutants identified in forward genetic screens, we sought to combine bulk segregant analysis and exome sequencing into a single step. Results Here we report the first use of exon capture sequencing to identify mutations in a non-mammalian, vertebrate model. We demonstrate that bulk segregant analysis coupled with exon capture sequencing is not only able to identify causative mutations but can also generate linkage information, facilitate the assembly of scaffolds, identify misassembles, and discover thousands of SNPs for fine mapping. Conclusion Exon capture sequencing and bulk segregant analysis is a rapid, inexpensive method to clone mutants identified in forward genetic screens. With sufficient meioses, this method can be generalized to any model system with a genome assembly, polished or unpolished, and in the latter case, it also provides many critical genomic resources.
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Affiliation(s)
- Florencia del Viso
- Department of Pediatrics and Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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