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Soto X, Burton J, Manning CS, Minchington T, Lea R, Lee J, Kursawe J, Rattray M, Papalopulu N. Sequential and additive expression of miR-9 precursors control timing of neurogenesis. Development 2022; 149:276990. [PMID: 36189829 PMCID: PMC9641661 DOI: 10.1242/dev.200474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/26/2022] [Indexed: 11/06/2022]
Abstract
MicroRNAs (miRs) have an important role in tuning dynamic gene expression. However, the mechanism by which they are quantitatively controlled is unknown. We show that the amount of mature miR-9, a key regulator of neuronal development, increases during zebrafish neurogenesis in a sharp stepwise manner. We characterize the spatiotemporal profile of seven distinct microRNA primary transcripts (pri-mir)-9s that produce the same mature miR-9 and show that they are sequentially expressed during hindbrain neurogenesis. Expression of late-onset pri-mir-9-1 is added on to, rather than replacing, the expression of early onset pri-mir-9-4 and -9-5 in single cells. CRISPR/Cas9 mutation of the late-onset pri-mir-9-1 prevents the developmental increase of mature miR-9, reduces late neuronal differentiation and fails to downregulate Her6 at late stages. Mathematical modelling shows that an adaptive network containing Her6 is insensitive to linear increases in miR-9 but responds to stepwise increases of miR-9. We suggest that a sharp stepwise increase of mature miR-9 is created by sequential and additive temporal activation of distinct loci. This may be a strategy to overcome adaptation and facilitate a transition of Her6 to a new dynamic regime or steady state.
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Affiliation(s)
- Ximena Soto
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK,Authors for correspondence (; )
| | - Joshua Burton
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Cerys S. Manning
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Thomas Minchington
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Robert Lea
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Jessica Lee
- Discovery Department, Medicines Discovery Catapult, Block 35, Mereside, Alderley Park, Alderley Edge, Cheshire, SK10 4TG, UK
| | - Jochen Kursawe
- School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
| | - Magnus Rattray
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Nancy Papalopulu
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK,Authors for correspondence (; )
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Burton J, Manning CS, Rattray M, Papalopulu N, Kursawe J. Inferring kinetic parameters of oscillatory gene regulation from single cell time-series data. J R Soc Interface 2021; 18:20210393. [PMID: 34583566 PMCID: PMC8479358 DOI: 10.1098/rsif.2021.0393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/26/2021] [Indexed: 11/19/2022] Open
Abstract
Gene expression dynamics, such as stochastic oscillations and aperiodic fluctuations, have been associated with cell fate changes in multiple contexts, including development and cancer. Single cell live imaging of protein expression with endogenous reporters is widely used to observe such gene expression dynamics. However, the experimental investigation of regulatory mechanisms underlying the observed dynamics is challenging, since these mechanisms include complex interactions of multiple processes, including transcription, translation and protein degradation. Here, we present a Bayesian method to infer kinetic parameters of oscillatory gene expression regulation using an auto-negative feedback motif with delay. Specifically, we use a delay-adapted nonlinear Kalman filter within a Metropolis-adjusted Langevin algorithm to identify posterior probability distributions. Our method can be applied to time-series data on gene expression from single cells and is able to infer multiple parameters simultaneously. We apply it to published data on murine neural progenitor cells and show that it outperforms alternative methods. We further analyse how parameter uncertainty depends on the duration and time resolution of an imaging experiment, to make experimental design recommendations. This work demonstrates the utility of parameter inference on time course data from single cells and enables new studies on cell fate changes and population heterogeneity.
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Affiliation(s)
- Joshua Burton
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Cerys S. Manning
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Magnus Rattray
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Nancy Papalopulu
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Jochen Kursawe
- School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
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Green DJ, Lenassi E, Manning CS, McGaughey D, Sharma V, Black GC, Ellingford JM, Sergouniotis PI. North Carolina Macular Dystrophy: Phenotypic Variability and Computational Analysis of Disease-Associated Noncoding Variants. Invest Ophthalmol Vis Sci 2021; 62:16. [PMID: 34125159 PMCID: PMC8212441 DOI: 10.1167/iovs.62.7.16] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Purpose North Carolina macular dystrophy (NCMD) is an autosomal dominant, congenital disorder affecting the central retina. Here, we report clinical and genetic findings in three families segregating NCMD and use epigenomic datasets from human tissues to gain insights into the effect of NCMD-implicated variants. Methods Clinical assessment and genetic testing were performed. Publicly available transcriptomic and epigenomic datasets were analyzed and the activity-by-contact method for scoring enhancer elements and linking them to target genes was used. Results A previously described, heterozygous, noncoding variant upstream of the PRDM13 gene was detected in all six affected study participants (chr6:100,040,987G>C [GRCh37/hg19]). Interfamilial and intrafamilial variability were observed; the visual acuity ranged from 0.0 to 1.6 LogMAR and fundoscopic findings ranged from visually insignificant, confluent, drusen-like macular deposits to coloboma-like macular lesions. Variable degrees of peripheral retinal spots (which were easily detected on widefield retinal imaging) were observed in all study subjects. Notably, a 6-year-old patient developed choroidal neovascularization and required treatment with intravitreal bevacizumab injections. Computational analysis of the five single nucleotide variants that have been implicated in NCMD revealed that these noncoding changes lie within two putative enhancer elements; these elements are predicted to interact with PRDM13 in the developing human retina. PRDM13 was found to be expressed in the fetal retina, with greatest expression in the amacrine precursor cell population. Conclusions We provide further evidence supporting the role of PRDM13 dysregulation in the pathogenesis of NCMD and highlight the usefulness of widefield retinal imaging in individuals suspected to have this condition.
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Affiliation(s)
- David J Green
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Eva Lenassi
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Cerys S Manning
- Division of Developmental Biology and Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - David McGaughey
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Vinod Sharma
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Graeme C Black
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Jamie M Ellingford
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Panagiotis I Sergouniotis
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Biga V, Hawley J, Soto X, Johns E, Han D, Bennett H, Adamson AD, Kursawe J, Glendinning P, Manning CS, Papalopulu N. A dynamic, spatially periodic, micro-pattern of HES5 underlies neurogenesis in the mouse spinal cord. Mol Syst Biol 2021; 17:e9902. [PMID: 34031978 PMCID: PMC8144840 DOI: 10.15252/msb.20209902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 03/30/2021] [Accepted: 04/06/2021] [Indexed: 11/12/2022] Open
Abstract
Ultradian oscillations of HES Transcription Factors (TFs) at the single‐cell level enable cell state transitions. However, the tissue‐level organisation of HES5 dynamics in neurogenesis is unknown. Here, we analyse the expression of HES5 ex vivo in the developing mouse ventral spinal cord and identify microclusters of 4–6 cells with positively correlated HES5 level and ultradian dynamics. These microclusters are spatially periodic along the dorsoventral axis and temporally dynamic, alternating between high and low expression with a supra‐ultradian persistence time. We show that Notch signalling is required for temporal dynamics but not the spatial periodicity of HES5. Few Neurogenin 2 cells are observed per cluster, irrespective of high or low state, suggesting that the microcluster organisation of HES5 enables the stable selection of differentiating cells. Computational modelling predicts that different cell coupling strengths underlie the HES5 spatial patterns and rate of differentiation, which is consistent with comparison between the motoneuron and interneuron progenitor domains. Our work shows a previously unrecognised spatiotemporal organisation of neurogenesis, emergent at the tissue level from the synthesis of single‐cell dynamics.
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Affiliation(s)
- Veronica Biga
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Joshua Hawley
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Ximena Soto
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Emma Johns
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Daniel Han
- Department of Mathematics, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Hayley Bennett
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Antony D Adamson
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Jochen Kursawe
- School of Mathematics and Statistics, University of St Andrews, St Andrews, UK
| | - Paul Glendinning
- Department of Mathematics, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
| | - Cerys S Manning
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Nancy Papalopulu
- Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
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5
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Manning CS, Biga V, Boyd J, Kursawe J, Ymisson B, Spiller DG, Sanderson CM, Galla T, Rattray M, Papalopulu N. Quantitative single-cell live imaging links HES5 dynamics with cell-state and fate in murine neurogenesis. Nat Commun 2019; 10:2835. [PMID: 31249377 PMCID: PMC6597611 DOI: 10.1038/s41467-019-10734-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 05/17/2019] [Indexed: 12/17/2022] Open
Abstract
During embryogenesis cells make fate decisions within complex tissue environments. The levels and dynamics of transcription factor expression regulate these decisions. Here, we use single cell live imaging of an endogenous HES5 reporter and absolute protein quantification to gain a dynamic view of neurogenesis in the embryonic mammalian spinal cord. We report that dividing neural progenitors show both aperiodic and periodic HES5 protein fluctuations. Mathematical modelling suggests that in progenitor cells the HES5 oscillator operates close to its bifurcation boundary where stochastic conversions between dynamics are possible. HES5 expression becomes more frequently periodic as cells transition to differentiation which, coupled with an overall decline in HES5 expression, creates a transient period of oscillations with higher fold expression change. This increases the decoding capacity of HES5 oscillations and correlates with interneuron versus motor neuron cell fate. Thus, HES5 undergoes complex changes in gene expression dynamics as cells differentiate.
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Affiliation(s)
- Cerys S. Manning
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Veronica Biga
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - James Boyd
- Department of Cellular and Molecular Physiology, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - Jochen Kursawe
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Bodvar Ymisson
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - David G. Spiller
- School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Christopher M. Sanderson
- Department of Cellular and Molecular Physiology, University of Liverpool, Crown Street, Liverpool, L69 3BX UK
| | - Tobias Galla
- Theoretical Physics Division, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL UK
| | - Magnus Rattray
- Division of Informatics, Imaging and Data Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Nancy Papalopulu
- School of Medical Sciences, Division of Developmental Biology and Medicine, Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester, M13 9PT UK
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Phillips NE, Manning CS, Pettini T, Biga V, Marinopoulou E, Stanley P, Boyd J, Bagnall J, Paszek P, Spiller DG, White MRH, Goodfellow M, Galla T, Rattray M, Papalopulu N. Stochasticity in the miR-9/Hes1 oscillatory network can account for clonal heterogeneity in the timing of differentiation. eLife 2016; 5:e16118. [PMID: 27700985 PMCID: PMC5050025 DOI: 10.7554/elife.16118] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 08/24/2016] [Indexed: 01/27/2023] Open
Abstract
Recent studies suggest that cells make stochastic choices with respect to differentiation or division. However, the molecular mechanism underlying such stochasticity is unknown. We previously proposed that the timing of vertebrate neuronal differentiation is regulated by molecular oscillations of a transcriptional repressor, HES1, tuned by a post-transcriptional repressor, miR-9. Here, we computationally model the effects of intrinsic noise on the Hes1/miR-9 oscillator as a consequence of low molecular numbers of interacting species, determined experimentally. We report that increased stochasticity spreads the timing of differentiation in a population, such that initially equivalent cells differentiate over a period of time. Surprisingly, inherent stochasticity also increases the robustness of the progenitor state and lessens the impact of unequal, random distribution of molecules at cell division on the temporal spread of differentiation at the population level. This advantageous use of biological noise contrasts with the view that noise needs to be counteracted.
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Affiliation(s)
- Nick E Phillips
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Cerys S Manning
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Tom Pettini
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Veronica Biga
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Elli Marinopoulou
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Peter Stanley
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - James Boyd
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - James Bagnall
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Pawel Paszek
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - David G Spiller
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michael RH White
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Marc Goodfellow
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom,Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom
| | - Tobias Galla
- Theoretical Physics, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Magnus Rattray
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nancy Papalopulu
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom,
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Manning CS, Hooper S, Sahai EA. Intravital imaging of SRF and Notch signalling identifies a key role for EZH2 in invasive melanoma cells. Oncogene 2014; 34:4320-32. [PMID: 25381824 PMCID: PMC4349503 DOI: 10.1038/onc.2014.362] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 07/01/2014] [Accepted: 07/24/2014] [Indexed: 12/18/2022]
Abstract
The acquisition of cell motility is an early step in melanoma metastasis. Here we use intravital imaging of signalling reporter cell-lines combined with genome-wide transcriptional analysis to define signalling pathways and genes associated with melanoma metastasis. Intravital imaging revealed heterogeneous cell behaviour in vivo: <10% of cells were motile and both singly moving cells and streams of cells were observed. Motile melanoma cells had increased Notch- and SRF-dependent transcription. Subsequent genome-wide analysis identified an overlapping set of genes associated with high Notch and SRF activity. We identified EZH2, a histone methyltransferase in the Polycomb repressive complex 2, as a regulator of these genes. Heterogeneity of EZH2 levels is observed in melanoma models, and co-ordinated upregulation of genes positively regulated by EZH2 is associated with melanoma metastasis. EZH2 was also identified as regulating the amelanotic phenotype of motile cells in vivo by suppressing expression of the P-glycoprotein Oca2. Analysis of patient samples confirmed an inverse relationship between EZH2 levels and pigment. EZH2 targeting with siRNA and chemical inhibition reduced invasion in mouse and human melanoma cell lines. The EZH2-regulated genes KIF2C and KIF22 are required for melanoma cell invasion and important for lung colonization. We propose that heterogeneity in EZH2 levels leads to heterogeneous expression of a cohort of genes associated with motile behaviour including KIF2C and KIF22. EZH2-dependent increased expression of these genes promotes melanoma cell motility and early steps in metastasis.
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Affiliation(s)
- C S Manning
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, London, UK
| | - S Hooper
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, London, UK
| | - E A Sahai
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, London, UK
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Manning CS, Jenkins R, Hooper S, Gerhardt H, Marais R, Adams S, Adams RH, van Rheenen J, Sahai E. Intravital imaging reveals conversion between distinct tumor vascular morphologies and localized vascular response to Sunitinib. IntraVital 2014. [DOI: 10.4161/intv.24790] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Manning CS, Lytle TF, Walker WW, Lytle JS. Life-cycle toxicity of bis(tributyltin) oxide to the sheepshead minnow (Cyprinodon variegatus). Arch Environ Contam Toxicol 1999; 37:258-266. [PMID: 10398777 DOI: 10.1007/s002449900513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of tributyltin (TBT) to the life cycle of the estuarine fish Cyprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproduction under continuous exposure to mean measured TBT concentrations of 5.4, 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Progeny isolated at the onset of reproduction by the parental generation (F0) were monitored for survival as embryos, survival as fry/juveniles, and growth 30 days postisolation. TBT, at a concentration of 5.4 microg/L, significantly reduced embryo survival of the F0 generation sheepshead minnows. By day 145 of the exposure, significant effects to the survival of this generation increased and included all test concentrations >/=0.66 microg/L. Survival of 0.66 microg/L was reduced 59% relative to control survival by termination of the F0 generation. Growth of F0 generation organisms as measured by standard length was significantly reduced only on day 90 at 3.2 microg/L, however no significant reductions of wet or dry weight related to treatment concentration were detected. Due to complete mortality of organisms exposed to 5.4 microg/L by study day 7, effects to fecundity and progeny were monitored at measured concentrations of 3.2, 1.3, 0.66, and 0.41 microg TBT/L. Fecundity, as measured by the production of viable eggs produced per female per day, was unaffected by any of the test treatments. All F1 generation embryos isolated from treatment chambers into 3.2 microg/L died. Survival, standard length, wet and dry weight of the F1 generation at the remaining treatment concentrations were unaffected. The results of this study indicate that exposure to TBT reduced survival of the F0 generation sheepshead minnow and establishes the lowest observed effect concentration (LOEC) as 0.66 microg TBT/L, and the no observed effect concentration (NOEC) as 0.41 microg TBT/L for this species.http://link.springer-ny. com/link/service/journals/00244/bibs/37n2p258.html
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Affiliation(s)
- C S Manning
- Gulf Coast Research Laboratory, P.O. Box 7000, Ocean Springs, Mississippi 39566-7000, USA
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Hawkins WE, Walker WW, James MO, Manning CS, Barnes DH, Heard CS, Overstreet RM. Carcinogenic effects of 1,2-dibromoethane (ethylene dibromide; EDB) in Japanese medaka (Oryzias latipes). Mutat Res 1998; 399:221-32. [PMID: 9672661 DOI: 10.1016/s0027-5107(97)00257-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The carcinogenicity of 1,2-dibromoethane (ethylene dibromide; EDB) was investigated in the Japanese medaka (Oryzias latipes), a small fish species. EDB was administered in water continuously for 97 days to a low concentration group, for 73 days to an intermediate concentration group, and intermittently for 24 h once each week over 97 days to a high concentration group. Medaka were 7 days old at the beginning of the tests. Mean measured EDB concentrations in the ambient water were 0.13 mg l-1, 6.20 mg l-1, and 18.58 mg l-1 in the low, intermediate, and high concentration groups, respectively. Two control groups, one inside and one outside the exposure apparatus, were used. Samples were examined histologically at 24, 36, and 58 weeks from the beginning of the tests. EDB was clearly carcinogenic to medaka in the intermediate and high concentration groups causing (1) hepatocellular adenomas and carcinomas, (2) cholangiomas, (3) chloangiocarcinomas, and (4) gall bladder papillary adenomas and adenocarcinomas. In separate studies, medaka exposed to 1.0 mg l-1 EDB for 2 to 5 weeks had elevated hepatic glutathione S-transferase activities, possibly indicating induction of a pathway that forms the reactive metabolite of EDB in mammals. SDS-PAGE of hepatic cytosolic fractions of EDB-exposed medaka showed a pronounced increase in a band at 26,000 Da, the expected position for GSH-S-transferase. Although little is known about EDB's mechanisms of action, medaka appear exceptionally sensitive to the carcinogenic effects of EDB and could serve as a model test species for studying similar compounds.
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Affiliation(s)
- W E Hawkins
- Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs 39564, USA.
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Walker WW, Manning CS, Overstreet RM, Hawkins WE. Development of aquarium fish models for environmental carcinogenesis: an intermittent-flow exposure system for volatile, hydrophobic chemicals. J Appl Toxicol 1985; 5:255-60. [PMID: 4045098 DOI: 10.1002/jat.2550050407] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
An intermittent-flow exposure system was designed to provide stable and manipulative concentrations of volatile and hydrophobic compounds to small aquatic animals for uninterrupted long periods. Test species for 28-day experiments included two aquarium fishes, the Japanese medaka (Oryzias latipes) and the king cobra guppy (Poecilia reticulata). Test chemicals included trichloroethylene, vinylidene chloride, bis(2-chloroethyl)ether, ethylene dichloride, and a mixture of carbon tetrachloride, trichloroethylene, chloroform, bromodichloromethane, chlorodibromomethane and bromoform. These compounds are drinking water biorefractories and are potentially carcinogenic. Concentrated aqueous toxicant solutions, delivered from a remote triple carboy dispensing system, were mixed with diluent water within an isolated chamber containing exposure aquaria and test fish. Toxicant concentrations measured throughout each exposure period proved to be stable within acceptable variability ranges as indicated by coefficients of variation generally less than 15%.
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12
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Goodman LR, Hansen DJ, Manning CS, Faas LF. Effects of Kepone on the sheepshead minnow in an entire life-cycle toxicity test. Arch Environ Contam Toxicol 1982; 11:335-342. [PMID: 6179480 DOI: 10.1007/bf01055210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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