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Kocere A, Chiavacci E, Soneson C, Wells HH, Méndez-Acevedo KM, MacGowan JS, Jacobson ST, Hiltabidle MS, Raghunath A, Shavit JA, Panáková D, Williams MLK, Robinson MD, Mosimann C, Burger A. Rbm8a deficiency causes hematopoietic defects by modulating Wnt/PCP signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.12.536513. [PMID: 37090609 PMCID: PMC10120739 DOI: 10.1101/2023.04.12.536513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Defects in blood development frequently occur among syndromic congenital anomalies. Thrombocytopenia-Absent Radius (TAR) syndrome is a rare congenital condition with reduced platelets (hypomegakaryocytic thrombocytopenia) and forelimb anomalies, concurrent with more variable heart and kidney defects. TAR syndrome associates with hypomorphic gene function for RBM8A/Y14 that encodes a component of the exon junction complex involved in mRNA splicing, transport, and nonsense-mediated decay. How perturbing a general mRNA-processing factor causes the selective TAR Syndrome phenotypes remains unknown. Here, we connect zebrafish rbm8a perturbation to early hematopoietic defects via attenuated non-canonical Wnt/Planar Cell Polarity (PCP) signaling that controls developmental cell re-arrangements. In hypomorphic rbm8a zebrafish, we observe a significant reduction of cd41-positive thrombocytes. rbm8a-mutant zebrafish embryos accumulate mRNAs with individual retained introns, a hallmark of defective nonsense-mediated decay; affected mRNAs include transcripts for non-canonical Wnt/PCP pathway components. We establish that rbm8a-mutant embryos show convergent extension defects and that reduced rbm8a function interacts with perturbations in non-canonical Wnt/PCP pathway genes wnt5b, wnt11f2, fzd7a, and vangl2. Using live-imaging, we found reduced rbm8a function impairs the architecture of the lateral plate mesoderm (LPM) that forms hematopoietic, cardiovascular, kidney, and forelimb skeleton progenitors as affected in TAR Syndrome. Both mutants for rbm8a and for the PCP gene vangl2 feature impaired expression of early hematopoietic/endothelial genes including runx1 and the megakaryocyte regulator gfi1aa. Together, our data propose aberrant LPM patterning and hematopoietic defects as consequence of attenuated non-canonical Wnt/PCP signaling upon reduced rbm8a function. These results also link TAR Syndrome to a potential LPM origin and a developmental mechanism.
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Affiliation(s)
- Agnese Kocere
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Elena Chiavacci
- Department of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Charlotte Soneson
- Department of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zürich, Zürich, Switzerland
| | - Harrison H. Wells
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Jacalyn S. MacGowan
- Center for Precision Environmental Health and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Seth T. Jacobson
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Max S. Hiltabidle
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Azhwar Raghunath
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jordan A. Shavit
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Daniela Panáková
- Max Delbrück Center (MDC) for Molecular Medicine in the Helmholtz Association, Berlin-Buch, Germany
- University Hospital Schleswig Holstein, Kiel, Germany
- German Centre for Cardiovascular Research (DZHK), partner site Hamburg, Kiel, Lübeck, Germany
| | - Margot L. K. Williams
- Center for Precision Environmental Health and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Mark D. Robinson
- Department of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zürich, Zürich, Switzerland
| | - Christian Mosimann
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Alexa Burger
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Efromson J, Ferrero G, Bègue A, Doman TJJ, Dugo C, Barker A, Saliu V, Reamey P, Kim K, Harfouche M, Yoder JA. Automated, high-throughput quantification of EGFP-expressing neutrophils in zebrafish by machine learning and a highly-parallelized microscope. PLoS One 2023; 18:e0295711. [PMID: 38060605 PMCID: PMC10703246 DOI: 10.1371/journal.pone.0295711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/26/2023] [Indexed: 12/18/2023] Open
Abstract
Normal development of the immune system is essential for overall health and disease resistance. Bony fish, such as the zebrafish (Danio rerio), possess all the major immune cell lineages as mammals and can be employed to model human host response to immune challenge. Zebrafish neutrophils, for example, are present in the transparent larvae as early as 48 hours post fertilization and have been examined in numerous infection and immunotoxicology reports. One significant advantage of the zebrafish model is the ability to affordably generate high numbers of individual larvae that can be arrayed in multi-well plates for high throughput genetic and chemical exposure screens. However, traditional workflows for imaging individual larvae have been limited to low-throughput studies using traditional microscopes and manual analyses. Using a newly developed, parallelized microscope, the Multi-Camera Array Microscope (MCAM™), we have optimized a rapid, high-resolution algorithmic method to count fluorescently labeled cells in zebrafish larvae in vivo. Using transgenic zebrafish larvae, in which neutrophils express EGFP, we captured 18 gigapixels of images across a full 96-well plate, in 75 seconds, and processed the resulting datastream, counting individual fluorescent neutrophils in all individual larvae in 5 minutes. This automation is facilitated by a machine learning segmentation algorithm that defines the most in-focus view of each larva in each well after which pixel intensity thresholding and blob detection are employed to locate and count fluorescent cells. We validated this method by comparing algorithmic neutrophil counts to manual counts in larvae subjected to changes in neutrophil numbers, demonstrating the utility of this approach for high-throughput genetic and chemical screens where a change in neutrophil number is an endpoint metric. Using the MCAM™ we have been able to, within minutes, acquire both enough data to create an automated algorithm and execute a biological experiment with statistical significance. Finally, we present this open-source software package which allows the user to train and evaluate a custom machine learning segmentation model and use it to localize zebrafish and analyze cell counts within the segmented region of interest. This software can be modified as needed for studies involving other zebrafish cell lineages using different transgenic reporter lines and can also be adapted for studies using other amenable model species.
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Affiliation(s)
- John Efromson
- Ramona Optics Inc., Durham, NC, United States of America
| | - Giuliano Ferrero
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Aurélien Bègue
- Ramona Optics Inc., Durham, NC, United States of America
| | | | - Clay Dugo
- Ramona Optics Inc., Durham, NC, United States of America
| | - Andi Barker
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
| | - Veton Saliu
- Ramona Optics Inc., Durham, NC, United States of America
| | - Paul Reamey
- Ramona Optics Inc., Durham, NC, United States of America
| | - Kanghyun Kim
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Mark Harfouche
- Ramona Optics Inc., Durham, NC, United States of America
| | - Jeffrey A. Yoder
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC, United States of America
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3
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Efromson J, Ferrero G, Bègue A, Doman TJJ, Dugo C, Barker A, Saliu V, Reamey P, Kim K, Harfouche M, Yoder JA. Automated, high-throughput quantification of EGFP-expressing neutrophils in zebrafish by machine learning and a highly-parallelized microscope. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.16.553550. [PMID: 37645798 PMCID: PMC10462042 DOI: 10.1101/2023.08.16.553550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Normal development of the immune system is essential for overall health and disease resistance. Bony fish, such as the zebrafish (Danio rerio), possess all the major immune cell lineages as mammals and can be employed to model human host response to immune challenge. Zebrafish neutrophils, for example, are present in the transparent larvae as early as 48 hours post fertilization and have been examined in numerous infection and immunotoxicology reports. One significant advantage of the zebrafish model is the ability to affordably generate high numbers of individual larvae that can be arrayed in multi-well plates for high throughput genetic and chemical exposure screens. However, traditional workflows for imaging individual larvae have been limited to low-throughput studies using traditional microscopes and manual analyses. Using a newly developed, parallelized microscope, the Multi-Camera Array Microscope (MCAM™), we have optimized a rapid, high-resolution algorithmic method to count fluorescently labeled cells in zebrafish larvae in vivo. Using transgenic zebrafish larvae, in which neutrophils express EGFP, we captured 18 gigapixels of images across a full 96-well plate, in 75 seconds, and processed the resulting datastream, counting individual fluorescent neutrophils in all individual larvae in 5 minutes. This automation is facilitated by a machine learning segmentation algorithm that defines the most in-focus view of each larva in each well after which pixel intensity thresholding and blob detection are employed to locate and count fluorescent cells. We validated this method by comparing algorithmic neutrophil counts to manual counts in larvae subjected to changes in neutrophil numbers, demonstrating the utility of this approach for high-throughput genetic and chemical screens where a change in neutrophil number is an endpoint metric. Using the MCAM™ we have been able to, within minutes, acquire both enough data to create an automated algorithm and execute a biological experiment with statistical significance. Finally, we present this open-source software package which allows the user to train and evaluate a custom machine learning segmentation model and use it to localize zebrafish and analyze cell counts within the segmented region of interest. This software can be modified as needed for studies involving other zebrafish cell lineages using different transgenic reporter lines and can also be adapted for studies using other amenable model species.
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Affiliation(s)
| | - Giuliano Ferrero
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC
| | | | | | | | - Andi Barker
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC
| | | | | | - Kanghyun Kim
- Department of Biomedical Engineering, Duke University, Durham, NC
| | | | - Jeffrey A. Yoder
- Department of Molecular Biological Sciences, North Carolina State University, Raleigh, NC
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Genetic duplication of tissue factor reveals subfunctionalization in venous and arterial hemostasis. PLoS Genet 2022; 18:e1010534. [PMID: 36449521 PMCID: PMC9744294 DOI: 10.1371/journal.pgen.1010534] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 12/12/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022] Open
Abstract
Tissue factor (TF) is an evolutionarily conserved protein necessary for initiation of hemostasis. Zebrafish have two copies of the tissue factor gene (f3a and f3b) as the result of an ancestral teleost fish duplication event (so called ohnologs). In vivo physiologic studies of TF function have been difficult given early lethality of TF knockout in the mouse. We used genome editing to produce knockouts of both f3a and f3b in zebrafish. Since ohnologs arose through sub- or neofunctionalization, they can unmask unknown functions of non-teleost genes and could reveal whether mammalian TF has developmental functions distinct from coagulation. Here we show that a single copy of either f3a or f3b is necessary and sufficient for normal lifespan. Complete loss of TF results in lethal hemorrhage by 2-4 months despite normal embryonic and vascular development. Larval vascular endothelial injury reveals predominant roles for TFa in venous circulation and TFb in arterial circulation. Finally, we demonstrate that loss of TF predisposes to a stress-induced cardiac tamponade independent of its role in fibrin formation. Overall, our data suggest partial subfunctionalization of TFa and TFb. This multigenic zebrafish model has the potential to facilitate study of the role of TF in different vascular beds.
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Raghunath A, Ferguson AC, Shavit JA. Fishing for answers to hemostatic and thrombotic disease: Genome editing in zebrafish. Res Pract Thromb Haemost 2022; 6:e12759. [PMID: 35949884 PMCID: PMC9354590 DOI: 10.1002/rth2.12759] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/27/2022] [Accepted: 06/15/2022] [Indexed: 01/22/2023] Open
Abstract
Over the past two decades, the teleost vertebrate Danio rerio (zebrafish) has emerged as a model for hemostasis and thrombosis. At genomic and functional levels, there is a high degree of conservation of the hemostatic system with that of mammals. Numerous features of the fish model offer unique advantages for investigating hemostasis and thrombosis. These include high fecundity, rapid and external development, optical transparency, and extensive functional homology with mammalian hemostasis and thrombosis. Zebrafish are particularly suited to genome-wide mutagenesis experiments for the study of modifier genes. They are also amenable to whole-organism small-molecule screens, a feature that is exceptionally relevant to hemostasis and thrombosis. Zebrafish coagulation factor knockouts that are in utero or neonatal lethal in mammals survive into adulthood before succumbing to hemorrhage or thrombosis, enabling studies not possible in mammals. In this illustrated review, we outline how zebrafish have been employed for the study of hemostasis and thrombosis using modern genome editing techniques, coagulation assays in larvae, and in vivo evaluation of patient-specific variants to infer causality and demonstrate pathogenicity. Zebrafish hemostasis and thrombosis models will continue to serve as a clinically directed basic research tool and powerful alternative to mammals for the development of new diagnostic markers and novel therapeutics for coagulation disorders through high-throughput genetic and small-molecule studies.
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Affiliation(s)
- Azhwar Raghunath
- Department of PediatricsUniversity of Michigan School of MedicineAnn ArborMichiganUSA
| | - Allison C. Ferguson
- Department of PediatricsUniversity of Michigan School of MedicineAnn ArborMichiganUSA
| | - Jordan A. Shavit
- Department of PediatricsUniversity of Michigan School of MedicineAnn ArborMichiganUSA,Department of Human GeneticsUniversity of Michigan School of MedicineAnn ArborMichiganUSA
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6
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Glucose inhibits haemostasis and accelerates diet-induced hyperlipidaemia in zebrafish larvae. Sci Rep 2021; 11:19049. [PMID: 34561530 PMCID: PMC8463691 DOI: 10.1038/s41598-021-98566-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/09/2021] [Indexed: 12/13/2022] Open
Abstract
Hyperglycaemia damages the microvasculature in part through the reduced recruitment of immune cells and interference with platelet signalling, leading to poor wound healing and accelerated lipid deposition in mammals. We investigated the utility of zebrafish larvae to model the effect of exogenous glucose on neutrophil and macrophage recruitment to a tail wound, wound-induced haemostasis, and chicken egg yolk feed challenge-induced hyperlipidaemia by supplementing larvae with exogenous glucose by immersion or injection. Neither method of glucose supplementation affected the recruitment of neutrophils and macrophages following tail transection. Glucose injection reduced thrombocyte retention and fibrin plug formation while only thrombocyte retention was reduced by glucose immersion following tail transection. We observed accelerated lipid accumulation in glucose-injected larvae challenged with high fat chicken egg yolk feeding. Our study identifies conserved and divergent effects of high glucose on inflammation, haemostasis, and hyperlipidaemia in zebrafish larvae compared to mammals.
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7
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Thapa S, Stachura DL. Deep Learning Approach for Quantification of Fluorescently Labeled Blood Cells in Danio rerio (Zebrafish). Bioinform Biol Insights 2021; 15:11779322211037770. [PMID: 34413636 PMCID: PMC8369963 DOI: 10.1177/11779322211037770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/15/2021] [Indexed: 11/15/2022] Open
Abstract
Neutrophils are a type of white blood cell essential for the function of the innate immune system. To elucidate mechanisms of neutrophil biology, many studies are performed in vertebrate animal model systems. In Danio rerio (zebrafish), in vivo imaging of neutrophils is possible due to transgenic strains that possess fluorescently labeled leukocytes. However, due to the relative abundance of neutrophils, the counting process is laborious and subjective. In this article, we propose the use of a custom trained “you only look once” (YOLO) machine learning algorithm to automate the identification and counting of fluorescently labeled neutrophils in zebrafish. Using this model, we found the correlation coefficient between human counting and the model equals r = 0.8207 with an 8.65% percent error, while variation among human counters was 5% to 12%. Importantly, the model was able to correctly validate results of a previously published article that quantitated neutrophils manually. While the accuracy can be further improved, this model notably achieves these results in mere minutes compared with hours via standard manual counting protocols and can be performed by anyone with basic programming knowledge. It further supports the use of deep learning models for high throughput analysis of fluorescently labeled blood cells in the zebrafish model system.
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Affiliation(s)
| | - David L Stachura
- David L Stachura, Department of Biological Sciences, California State University, Chico, 400 W. 1st Ave, Chico, CA 95929-0515, USA.
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8
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A genetic modifier of venous thrombosis in zebrafish reveals a functional role for fibrinogen AαE in early hemostasis. Blood Adv 2021; 4:5480-5491. [PMID: 33166405 DOI: 10.1182/bloodadvances.2020001472] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/02/2020] [Indexed: 12/30/2022] Open
Abstract
Plasma fibrinogen molecules comprise 2 copies of Aα, Bβ, and γ chains folded into a hexameric protein. A minor fibrinogen isoform with an extended Aα chain (AαE) is more abundant in newborn human blood than in adults. Larval zebrafish produce predominantly AαE-containing fibrinogen, but its functional significance is unclear. In 3-day-old zebrafish, when hemostasis is reliant on fibrinogen and erythrocyte-rich clotting but is largely thrombocyte-independent, we measured the time to occlusion (TTO) in a laser-induced venous thrombosis assay in 3 zebrafish strains (AB, TU, and AB × TL hybrids). AB larvae showed delayed TTO compared with the TU and AB × TL strains. Mating AB with TU or TL produced larvae with a TU-like TTO. In contrast to TU, AB larvae failed to produce fibrinogen AαE, due to a mutation in the AαE-specific coding region of fibrinogen α-chain gene (fga). We investigated whether the lack of AαE explained the delayed AB TTO. Transgenic expression of AαE, but not Aα, shortened the AB TTO to that of TU. AαE rescued venous occlusion in fibrinogen mutants or larvae with morpholino-targeted fibrinogen α-chain messenger RNA, but Aα was less effective. In 5-day-old larvae, circulating thrombocytes contribute to hemostasis, as visualized in Tg(itga2b:EGFP) transgenics. Laser-induced venous thrombocyte adhesion and aggregation is reduced in fibrinogen mutants, but transgenic expression of Aα or AαE restored similar thrombocyte accumulation at the injury site. Our data demonstrate a genetic modifier of venous thrombosis and a role for fibrinogen AαE in early developmental blood coagulation, and suggest a link between differentially expressed fibrinogen isoforms and the cell types available for clotting.
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9
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Analysis of factor V in zebrafish demonstrates minimal levels needed for early hemostasis. Blood Adv 2020; 3:1670-1680. [PMID: 31167819 DOI: 10.1182/bloodadvances.2018029066] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 04/17/2019] [Indexed: 12/28/2022] Open
Abstract
In humans, coagulation factor V (FV) deficiency is a rare, clinically heterogeneous bleeding disorder, suggesting that genetic modifiers may contribute to disease expressivity. Zebrafish possess many distinct advantages including high fecundity, optical clarity, external development, and homology with the mammalian hemostatic system, features that make it ideal for genetic studies. Our aim was to study the role of FV in zebrafish through targeted mutagenesis and apply the model to the study of human F5 variants. CRISPR-mediated genome editing of the zebrafish f5 locus was performed, generating mutants homozygous for a 49 base pair deletion in exon 4. Thrombus formation secondary to vascular endothelial injury was absent in f5 -/- mutant embryos and larvae. Despite this severe hemostatic defect, homozygous mutants survived before succumbing to severe hemorrhage in adulthood. Human F5 variants of uncertain significance from patients with FV deficiency were evaluated, and the causative mutations identified and stratified by their ability to restore thrombus formation in larvae. Analysis of these novel mutations demonstrates variable residual FV function, with minimal activity being required to restore hemostasis in response to laser-induced endothelial injury. This in vivo evaluation may be beneficial for patients whose factor activity levels lack correlation with bleeding symptomatology, although limitations exist. Furthermore, homozygous mutant embryos tolerate what is a severe and lethal defect in mammals, suggesting the possibility of species-specific factors enabling survival, and allowing further study not possible in the mouse. Identification of these factors or other genetic modifiers could lead to novel therapeutic modalities.
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Soslau G. The role of the red blood cell and platelet in the evolution of mammalian and avian endothermy. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 334:113-127. [DOI: 10.1002/jez.b.22922] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/04/2019] [Accepted: 11/09/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Gerald Soslau
- Department of Biochemistry and Molecular BiologyDrexel University College of MedicinePhiladelphia Pennsylvania
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11
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Rost MS, Shestopalov I, Liu Y, Vo AH, Richter CE, Emly SM, Barrett FG, Stachura DL, Holinstat M, Zon LI, Shavit JA. Nfe2 is dispensable for early but required for adult thrombocyte formation and function in zebrafish. Blood Adv 2018; 2:3418-3427. [PMID: 30504234 PMCID: PMC6290098 DOI: 10.1182/bloodadvances.2018021865] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 10/31/2018] [Indexed: 12/20/2022] Open
Abstract
The NFE2 transcription factor is expressed in multiple hematopoietic lineages with a well-defined role in regulating megakaryocyte biogenesis and platelet production in mammals. Mice deficient in NFE2 develop severe thrombocytopenia with lethality resulting from neonatal hemorrhage. Recent data in mammals reveal potential differences in embryonic and adult thrombopoiesis. Multiple studies in zebrafish have revealed mechanistic insights into hematopoiesis, although thrombopoiesis has been less studied. Rather than platelets, zebrafish possess thrombocytes, which are nucleated cells with similar functional properties. Using transcription activator-like effector nucleases to generate mutations in nfe2, we show that unlike mammals, zebrafish survive to adulthood in the absence of Nfe2. Despite developing severe thrombocytopenia, homozygous mutants do not display overt hemorrhage or reduced survival. Surprisingly, quantification of circulating thrombocytes in mutant 6-day-old larvae revealed no significant differences from wild-type siblings. Both wild-type and nfe2 null larvae formed thrombocyte-rich clots in response to endothelial injury. In addition, ex vivo thrombocytic colony formation was intact in nfe2 mutants, and adult kidney marrow displayed expansion of hematopoietic progenitors. These data suggest that loss of Nfe2 results in a late block in adult thrombopoiesis, with secondary expansion of precursors: features consistent with mammals. Overall, our data suggest parallels with erythropoiesis, including distinct primitive and definitive pathways of development and potential for a previously unknown Nfe2-independent pathway of embryonic thrombopoiesis. Long-term homozygous mutant survival will facilitate in-depth study of Nfe2 deficiency in vivo, and further investigation could lead to alternative methodologies for the enhancement of platelet production.
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Affiliation(s)
- Megan S Rost
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
| | - Ilya Shestopalov
- Boston Children's Hospital and Harvard Medical School, Boston, MA
| | - Yang Liu
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
| | - Andy H Vo
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
| | - Catherine E Richter
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
| | - Sylvia M Emly
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
| | | | - David L Stachura
- Department of Biological Sciences, California State University Chico, Chico, CA
| | - Michael Holinstat
- Department of Pharmacology, University of Michigan, Ann Arbor, MI; and
| | - Leonard I Zon
- Boston Children's Hospital and Harvard Medical School, Boston, MA
- Stem Cell Program and Division of Hematology/Oncology, Harvard Stem Cell Institute, Stem Cell and Regenerative Biology Department, Dana-Farber Cancer Institute and Howard Hughes Medical Institute, Boston, MA
| | - Jordan A Shavit
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI
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12
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Genome editing of factor X in zebrafish reveals unexpected tolerance of severe defects in the common pathway. Blood 2017; 130:666-676. [PMID: 28576875 DOI: 10.1182/blood-2017-02-765206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/23/2017] [Indexed: 12/24/2022] Open
Abstract
Deficiency of factor X (F10) in humans is a rare bleeding disorder with a heterogeneous phenotype and limited therapeutic options. Targeted disruption of F10 and other common pathway factors in mice results in embryonic/neonatal lethality with rapid resorption of homozygous mutants, hampering additional studies. Several of these mutants also display yolk sac vascular defects, suggesting a role for thrombin signaling in vessel development. The zebrafish is a vertebrate model that demonstrates conservation of the mammalian hemostatic and vascular systems. We have leveraged these advantages for in-depth study of the role of the coagulation cascade in the developmental regulation of hemostasis and vasculogenesis. In this article, we show that ablation of zebrafish f10 by using genome editing with transcription activator-like effector nucleases results in a major embryonic hemostatic defect. However, widespread hemorrhage and subsequent lethality does not occur until later stages, with absence of any detectable defect in vascular development. We also use f10-/- zebrafish to confirm 5 novel human F10 variants as causative mutations in affected patients, providing a rapid and reliable in vivo model for testing the severity of F10 variants. These findings as well as the prolonged survival of f10-/- mutants will enable us to expand our understanding of the molecular mechanisms of hemostasis, including a platform for screening variants of uncertain significance in patients with F10 deficiency and other coagulation disorders. Further study as to how fish tolerate what is an early lethal mutation in mammals could facilitate improvement of diagnostics and therapeutics for affected patients with bleeding disorders.
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13
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Abstract
Hemostasis is a coordinated system through which blood is prevented from exiting a closed circulatory system. We have taken advantage of the zebrafish, an emerging model for the study of blood coagulation, and describe three techniques for quantitative analysis of primary and secondary hemostasis. Collectively, these three techniques comprise a toolset to aid in our understanding of hemostasis and pathological clotting.
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Affiliation(s)
- M S Rost
- University of Michigan, Ann Arbor, MI, United States
| | | | - J A Shavit
- University of Michigan, Ann Arbor, MI, United States
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