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Wopat S, Adhyapok P, Daga B, Crawford JM, Norman J, Bagwell J, Peskin B, Magre I, Fogerson SM, Levic DS, Di Talia S, Kiehart DP, Charbonneau P, Bagnat M. Notochord segmentation in zebrafish controlled by iterative mechanical signaling. Dev Cell 2024:S1534-5807(24)00238-7. [PMID: 38697108 DOI: 10.1016/j.devcel.2024.04.013] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 01/25/2024] [Accepted: 04/12/2024] [Indexed: 05/04/2024]
Abstract
In bony fishes, patterning of the vertebral column, or spine, is guided by a metameric blueprint established in the notochord sheath. Notochord segmentation begins days after somitogenesis concludes and can occur in its absence. However, somite patterning defects lead to imprecise notochord segmentation, suggesting that these processes are linked. Here, we identify that interactions between the notochord and the axial musculature ensure precise spatiotemporal segmentation of the zebrafish spine. We demonstrate that myoseptum-notochord linkages drive notochord segment initiation by locally deforming the notochord extracellular matrix and recruiting focal adhesion machinery at these contact points. Irregular somite patterning alters this mechanical signaling, causing non-sequential and dysmorphic notochord segmentation, leading to altered spine development. Using a model that captures myoseptum-notochord interactions, we find that a fixed spatial interval is critical for driving sequential segment initiation. Thus, mechanical coupling of axial tissues facilitates spatiotemporal spine patterning.
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Affiliation(s)
- Susan Wopat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Priyom Adhyapok
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Bijoy Daga
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | | | - James Norman
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Brianna Peskin
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Indrasen Magre
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | | | - Daniel S Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Stefano Di Talia
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | | | - Patrick Charbonneau
- Department of Chemistry, Duke University, Durham, NC 27708, USA; Department of Physics, Duke University, Durham, NC 27708, USA.
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
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2
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Levic DS, Niedzwiecki D, Kandakatla A, Karlovich NS, Juneja A, Park J, Stolarchuk C, Adams S, Willer JR, Schaner MR, Lian G, Beasley C, Marjoram L, Flynn AD, Valentine JF, Onken JE, Sheikh SZ, Davis EE, Evason KJ, Garman KS, Bagnat M. TNF promoter hypomethylation is associated with mucosal inflammation in IBD and anti-TNF response. medRxiv 2024:2024.02.05.24302343. [PMID: 38370739 PMCID: PMC10871362 DOI: 10.1101/2024.02.05.24302343] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Background and aims Inflammatory Bowel Diseases (IBD) are chronic inflammatory conditions influenced heavily by environmental factors. DNA methylation is a form of epigenetic regulation linking environmental stimuli to gene expression changes and inflammation. Here, we investigated how DNA methylation of the TNF promoter differs between inflamed and uninflamed mucosa of IBD patients, including anti-TNF responders and non-responders. Methods We obtained mucosal biopsies from 200 participants (133 IBD and 67 controls) and analyzed TNF promoter methylation using bisulfite sequencing, comparing inflamed with uninflamed segments, in addition to paired inflamed/uninflamed samples from individual patients. We conducted similar analyses on purified intestinal epithelial cells from bowel resections. We also compared TNF methylation levels of inflamed and uninflamed mucosa from a separate cohort of 15 anti-TNF responders and 17 non-responders. Finally, we sequenced DNA methyltransferase genes to identify rare variants in IBD patients and functionally tested them using rescue experiments in a zebrafish genetic model of DNA methylation deficiency. Results TNF promoter methylation levels were decreased in inflamed mucosa of IBD patients and correlated with disease severity. Isolated IECs from inflamed tissue showed proportional decreases in TNF methylation. Anti-TNF non-responders showed lower levels of TNF methylation than responders in uninflamed mucosa. Our sequencing analysis revealed two missense variants in DNMT1, one of which had reduced function in vivo. Conclusions Our study reveals an association of TNF promoter hypomethylation with mucosal inflammation, suggesting that IBD patients may be particularly sensitive to inflammatory environmental insults affecting DNA methylation. Together, our analyses indicate that TNF promoter methylation analysis may aid in the characterization of IBD status and evaluation of anti-TNF therapy response.
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Affiliation(s)
- Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - Donna Niedzwiecki
- Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - Apoorva Kandakatla
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, NC, USA
| | - Norah S. Karlovich
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, NC, USA
| | - Arjun Juneja
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - Jieun Park
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - Christina Stolarchuk
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, NC, USA
| | - Shanté Adams
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, USA
| | - Jason R. Willer
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, USA
| | - Matthew R. Schaner
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Grace Lian
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Caroline Beasley
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Ann D. Flynn
- Division of Gastroenterology, Hepatology and Nutrition, University of Utah Health, Salt Lake City, Utah
| | - John F. Valentine
- Division of Gastroenterology, Hepatology and Nutrition, University of Utah Health, Salt Lake City, Utah
| | - Jane E. Onken
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, NC, USA
| | - Shehzad Z. Sheikh
- Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Erica E. Davis
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL, USA
| | - Kimberley J. Evason
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - Katherine S. Garman
- Division of Gastroenterology, Department of Medicine, Duke University, Durham, NC, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC, USA
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3
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Anbarci DN, McKey1 J, Levic DS, Bagnat M, Capel B. Rediscovering the Rete Ovarii: a secreting auxiliary structure to the ovary. bioRxiv 2024:2023.11.08.566085. [PMID: 37986754 PMCID: PMC10659334 DOI: 10.1101/2023.11.08.566085] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The rete ovarii (RO) is an appendage of the ovary that has been given little attention. Although the RO appears in drawings of the ovary in early versions of Gray's Anatomy, it disappeared from recent textbooks, and is often dismissed as a functionless vestige in the adult ovary. Using PAX8 immunostaining and confocal microscopy, we characterized the fetal development of the RO in the context of the ovary. The RO consists of three distinct regions that persist in adult life, the intraovarian rete (IOR), the extraovarian rete (EOR), and the connecting rete (CR). While the cells of the IOR appear to form solid cords within the ovary, the EOR rapidly develops into a convoluted tubular epithelium ending in a distal dilated tip. Cells of the EOR are ciliated and exhibit cellular trafficking capabilities. The CR, connecting the EOR to the IOR, gradually acquires tubular epithelial characteristics by birth. Using microinjections into the distal dilated tip of the EOR, we found that luminal contents flow towards the ovary. Mass spectrometry revealed that the EOR lumen contains secreted proteins potentially important for ovarian function. We show that the cells of the EOR are closely associated with vasculature and macrophages, and are contacted by neuronal projections, consistent with a role as a sensory appendage of the ovary. The direct proximity of the RO to the ovary and its integration with the extraovarian landscape suggest that it plays an important role in ovary development and homeostasis.
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Affiliation(s)
- Dilara N. Anbarci
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710
| | - Jennifer McKey1
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora CO 80045
| | - Daniel S. Levic
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710
| | - Michel Bagnat
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710
| | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710
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He J, Blazeski A, Nilanthi U, Menéndez J, Pirani SC, Levic DS, Bagnat M, Singh MK, Raya JG, García-Cardeña G, Torres-Vázquez J. Plxnd1-mediated mechanosensing of blood flow controls the caliber of the Dorsal Aorta via the transcription factor Klf2. bioRxiv 2024:2024.01.24.576555. [PMID: 38328196 PMCID: PMC10849625 DOI: 10.1101/2024.01.24.576555] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The cardiovascular system generates and responds to mechanical forces. The heartbeat pumps blood through a network of vascular tubes, which adjust their caliber in response to the hemodynamic environment. However, how endothelial cells in the developing vascular system integrate inputs from circulatory forces into signaling pathways to define vessel caliber is poorly understood. Using vertebrate embryos and in vitro-assembled microvascular networks of human endothelial cells as models, flow and genetic manipulations, and custom software, we reveal that Plexin-D1, an endothelial Semaphorin receptor critical for angiogenic guidance, employs its mechanosensing activity to serve as a crucial positive regulator of the Dorsal Aorta's (DA) caliber. We also uncover that the flow-responsive transcription factor KLF2 acts as a paramount mechanosensitive effector of Plexin-D1 that enlarges endothelial cells to widen the vessel. These findings illuminate the molecular and cellular mechanisms orchestrating the interplay between cardiovascular development and hemodynamic forces.
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Affiliation(s)
- Jia He
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Adriana Blazeski
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women’s Hospital, Boston, MA, USA and Harvard Medical School, Boston, MA, USA
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Uthayanan Nilanthi
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore, 169857
| | - Javier Menéndez
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Samuel C. Pirani
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Manvendra K. Singh
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore, 169857
- National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore, 169609
| | - José G Raya
- Department of Radiology, New York University School of Medicine, New York, NY 10016, USA
| | - Guillermo García-Cardeña
- Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women’s Hospital, Boston, MA, USA and Harvard Medical School, Boston, MA, USA
- Cardiovascular Disease Initiative, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jesús Torres-Vázquez
- Department of Cell Biology, NYU Grossman School of Medicine, New York, NY 10016, USA
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Levic DS, Bagnat M. Polarized transport of membrane and secreted proteins during lumen morphogenesis. Semin Cell Dev Biol 2023; 133:65-73. [PMID: 35307284 PMCID: PMC9481742 DOI: 10.1016/j.semcdb.2022.03.016] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/09/2022] [Accepted: 03/12/2022] [Indexed: 10/18/2022]
Abstract
A ubiquitous feature of animal development is the formation of fluid-filled cavities or lumina, which transport gases and fluids across tissues and organs. Among different species, lumina vary drastically in size, scale, and complexity. However, all lumen formation processes share key morphogenetic principles that underly their development. Fundamentally, a lumen simply consists of epithelial cells that encapsulate a continuous internal space, and a common way of building a lumen is via opening and enlarging by filling it with fluid and/or macromolecules. Here, we discuss how polarized targeting of membrane and secreted proteins regulates lumen formation, mainly focusing on ion transporters in vertebrate model systems. We also discuss mechanistic differences observed among invertebrates and vertebrates and describe how the unique properties of the Na+/K+-ATPase and junctional proteins can promote polarization of immature epithelia to build lumina de novo in developing organs.
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Affiliation(s)
- Daniel S Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
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6
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Luderman LN, Michaels MT, Levic DS, Knapik EW. Zebrafish Erc1b mediates motor innervation and organization of craniofacial muscles in control of jaw movement. Dev Dyn 2023; 252:104-123. [PMID: 35708710 DOI: 10.1002/dvdy.511] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/31/2022] [Accepted: 06/03/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Movement of the lower jaw, a common behavior observed among vertebrates, is required for eating and processing food. This movement is controlled by signals sent from the trigeminal motor nerve through neuromuscular junctions (NMJs) to the masticatory muscles. Dysfunctional jaw movements contribute to craniomandibular disorders, yet the pathophysiology of these disorders is not well understood, as limited studies have been conducted on the molecular mechanisms of jaw movement. RESULTS Using erc1b/kimm533 genetic loss of function mutant, we evaluated lower jaw muscle organization and innervation by the cranial motor nerves in developing zebrafish. Using time-lapse confocal imaging of the erc1b mutant in a transgenic fluorescent reporter line, we found delayed trigeminal nerve growth and disrupted nerve branching architecture during muscle innervation. By automated 3D image analysis of NMJ distribution, we identified an increased number of small, disorganized NMJ clusters in erc1b mutant larvae compared to WT siblings. Using genetic replacement experiments, we determined the Rab GTPase binding domain of Erc1b is required for cranial motor nerve branching, but not NMJ organization or muscle attachment. CONCLUSIONS We identified Erc1b/ERC1 as a novel component of a genetic pathway contributing to muscle organization, trigeminal nerve outgrowth, and NMJ spatial distribution during development that is required for jaw movement.
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Affiliation(s)
- Lauryn N Luderman
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Mackenzie T Michaels
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Daniel S Levic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
- Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Ela W Knapik
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
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7
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Levic DS, Bagnat M. Self-organization of apical membrane protein sorting in epithelial cells. FEBS J 2022; 289:659-670. [PMID: 33864720 PMCID: PMC8522177 DOI: 10.1111/febs.15882] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/25/2021] [Accepted: 04/14/2021] [Indexed: 02/03/2023]
Abstract
Polarized epithelial cells are characterized by the asymmetric distribution of proteins between apical and basolateral domains of the plasma membrane. This asymmetry is highly conserved and is fundamental to epithelial cell physiology, development, and homeostasis. How proteins are segregated for apical or basolateral delivery, a process known as sorting, has been the subject of considerable investigation for decades. Despite these efforts, the rules guiding apical sorting are poorly understood and remain controversial. Here, we consider mechanisms of apical membrane protein sorting and argue that they are largely driven by self-organization and biophysical principles. The preponderance of data to date is consistent with the idea that apical sorting is not ruled by a dedicated protein-based sorting machinery and relies instead on the concerted effects of oligomerization, phase separation of lipids and proteins in membranes, and pH-dependent glycan interactions.
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Affiliation(s)
- Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA,Correspondence to Michel Bagnat: or Dan Levic:
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA,Correspondence to Michel Bagnat: or Dan Levic:
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8
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Levic DS, Yamaguchi N, Wang S, Knaut H, Bagnat M. Knock-in tagging in zebrafish facilitated by insertion into non-coding regions. Development 2021; 148:dev199994. [PMID: 34495314 PMCID: PMC8513609 DOI: 10.1242/dev.199994] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/27/2021] [Indexed: 11/20/2022]
Abstract
Zebrafish provide an excellent model for in vivo cell biology studies because of their amenability to live imaging. Protein visualization in zebrafish has traditionally relied on overexpression of fluorescently tagged proteins from heterologous promoters, making it difficult to recapitulate endogenous expression patterns and protein function. One way to circumvent this problem is to tag the proteins by modifying their endogenous genomic loci. Such an approach is not widely available to zebrafish researchers because of inefficient homologous recombination and the error-prone nature of targeted integration in zebrafish. Here, we report a simple approach for tagging proteins in zebrafish on their N or C termini with fluorescent proteins by inserting PCR-generated donor amplicons into non-coding regions of the corresponding genes. Using this approach, we generated endogenously tagged alleles for several genes that are crucial for epithelial biology and organ development, including the tight junction components ZO-1 and Cldn15la, the trafficking effector Rab11a, the apical polarity protein aPKC and the ECM receptor Integrin β1b. Our approach facilitates the generation of knock-in lines in zebrafish, opening the way for accurate quantitative imaging studies.
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Affiliation(s)
- Daniel S. Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Naoya Yamaguchi
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Siyao Wang
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Holger Knaut
- Skirball Institute of Biomolecular Medicine, New York University Grossman School of Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
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9
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Levic DS, Ryan S, Marjoram L, Honeycutt J, Bagwell J, Bagnat M. Distinct roles for luminal acidification in apical protein sorting and trafficking in zebrafish. J Cell Biol 2020; 219:133852. [PMID: 32328632 PMCID: PMC7147097 DOI: 10.1083/jcb.201908225] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 08/29/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Epithelial cell physiology critically depends on the asymmetric distribution of channels and transporters. However, the mechanisms targeting membrane proteins to the apical surface are still poorly understood. Here, we performed a visual forward genetic screen in the zebrafish intestine and identified mutants with defective apical targeting of membrane proteins. One of these mutants, affecting the vacuolar H+-ATPase gene atp6ap1b, revealed specific requirements for luminal acidification in apical, but not basolateral, membrane protein sorting and transport. Using a low temperature block assay combined with genetic and pharmacologic perturbation of luminal pH, we monitored transport of newly synthesized membrane proteins from the TGN to apical membrane in live zebrafish. We show that vacuolar H+-ATPase activity regulates sorting of O-glycosylated proteins at the TGN, as well as Rab8-dependent post-Golgi trafficking of different classes of apical membrane proteins. Thus, luminal acidification plays distinct and specific roles in apical membrane biogenesis.
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Affiliation(s)
| | - Sean Ryan
- Department of Cell Biology, Duke University, Durham, NC
| | | | | | | | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC
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10
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Unlu G, Gamazon ER, Qi X, Levic DS, Bastarache L, Denny JC, Roden DM, Mayzus I, Breyer M, Zhong X, Konkashbaev AI, Rzhetsky A, Knapik EW, Cox NJ. GRIK5 Genetically Regulated Expression Associated with Eye and Vascular Phenomes: Discovery through Iteration among Biobanks, Electronic Health Records, and Zebrafish. Am J Hum Genet 2019; 104:503-519. [PMID: 30827500 PMCID: PMC6407495 DOI: 10.1016/j.ajhg.2019.01.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/29/2019] [Indexed: 12/15/2022] Open
Abstract
Although the use of model systems for studying the mechanism of mutations that have a large effect is common, we highlight here the ways that zebrafish-model-system studies of a gene, GRIK5, that contributes to the polygenic liability to develop eye diseases have helped to illuminate a mechanism that implicates vascular biology in eye disease. A gene-expression prediction derived from a reference transcriptome panel applied to BioVU, a large electronic health record (EHR)-linked biobank at Vanderbilt University Medical Center, implicated reduced GRIK5 expression in diverse eye diseases. We tested the function of GRIK5 by depletion of its ortholog in zebrafish, and we observed reduced blood vessel numbers and integrity in the eye and increased vascular permeability. Analyses of EHRs in >2.6 million Vanderbilt subjects revealed significant comorbidity of eye and vascular diseases (relative risks 2-15); this comorbidity was confirmed in 150 million individuals from a large insurance claims dataset. Subsequent studies in >60,000 genotyped BioVU participants confirmed the association of reduced genetically predicted expression of GRIK5 with comorbid vascular and eye diseases. Our studies pioneer an approach that allows a rapid iteration of the discovery of gene-phenotype relationships to the primary genetic mechanism contributing to the pathophysiology of human disease. Our findings also add dimension to the understanding of the biology driven by glutamate receptors such as GRIK5 (also referred to as GLUK5 in protein form) and to mechanisms contributing to human eye diseases.
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Affiliation(s)
- Gokhan Unlu
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Eric R Gamazon
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Data Science Institute, Vanderbilt University, Nashville, TN 37232, USA; Clare Hall, University of Cambridge, Cambridge CB3 9AL, UK
| | - Xinzi Qi
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel S Levic
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lisa Bastarache
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Departments of Medicine and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Joshua C Denny
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Departments of Medicine and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Dan M Roden
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Departments of Medicine and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Ilya Mayzus
- Departments of Medicine and Human Genetics, the University of Chicago, Chicago, IL 60637, USA
| | - Max Breyer
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Xue Zhong
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anuar I Konkashbaev
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrey Rzhetsky
- Departments of Medicine and Human Genetics, the University of Chicago, Chicago, IL 60637, USA
| | - Ela W Knapik
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Nancy J Cox
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Data Science Institute, Vanderbilt University, Nashville, TN 37232, USA.
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11
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Garcia J, Bagwell J, Njaine B, Norman J, Levic DS, Wopat S, Miller SE, Liu X, Locasale JW, Stainier DYR, Bagnat M. Sheath Cell Invasion and Trans-differentiation Repair Mechanical Damage Caused by Loss of Caveolae in the Zebrafish Notochord. Curr Biol 2017. [PMID: 28648824 DOI: 10.1016/j.cub.2017.05.035] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The notochord, a conserved axial structure required for embryonic axis elongation and spine development, consists of giant vacuolated cells surrounded by an epithelial sheath [1-3]. During morphogenesis, vacuolated cells maintain their structural integrity despite being under constant mechanical stress [4]. We hypothesized that the high density of caveolae present in vacuolated cells [5, 6] could buffer mechanical tension. Caveolae are 50- to 80-nm membrane invaginations lined by cage-like polygonal structures [7, 8] formed by caveolin 1 (Cav1) or Cav3 and one of the cavin proteins [6, 9-11]. Recent in vitro work has shown that plasma membrane caveolae constitute a membrane reservoir that can buffer mechanical stresses such as stretching or osmotic swelling [12]. Moreover, mechanical integrity of vascular and muscle cells is partly dependent on caveolae [13-15]. However, the in vivo mechano-protective roles of caveolae have only begun to be explored. Using zebrafish mutants for cav1, cav3, and cavin1b, we show that caveolae are essential for notochord integrity. Upon loss of caveola function, vacuolated cells collapse at discrete positions under the mechanical strain of locomotion. Then, sheath cells invade the inner notochord and differentiate into vacuolated cells, thereby restoring notochord function and allowing normal spine development. Our data further indicate that nucleotides released by dying vacuolated cells promote sheath cell vacuolization and trans-differentiation. This work reveals a novel structural role for caveolae in vertebrates and provides unique insights into the mechanisms that safeguard notochord and spine development.
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Affiliation(s)
- Jamie Garcia
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Jennifer Bagwell
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Brian Njaine
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - James Norman
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Daniel S Levic
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Susan Wopat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA
| | - Sara E Miller
- Department of Pathology, Duke University, Durham, NC 27710, USA
| | - Xiaojing Liu
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Jason W Locasale
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
| | - Didier Y R Stainier
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Michel Bagnat
- Department of Cell Biology, Duke University, Durham, NC 27710, USA.
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12
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Pfaltzgraff ER, Samade R, Adams R, Levic DS, Bader DM, Fleming AE. Interprofessional projects promote and strengthen interdisciplinary collaboration. Med Educ 2015; 49:1156-1157. [PMID: 26494089 PMCID: PMC4680992 DOI: 10.1111/medu.12860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
| | | | | | | | - David M. Bader
- Department of Cell and Developmental Biology
- Vanderbilt University School of Medicine
- Division of Cardiovascular Medicine
| | - Amy E. Fleming
- Vanderbilt University School of Medicine
- Department of Pediatrics
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13
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Zou P, Wu SY, Koteiche HA, Mishra S, Levic DS, Knapik E, Chen W, Mchaourab HS. A conserved role of αA-crystallin in the development of the zebrafish embryonic lens. Exp Eye Res 2015; 138:104-13. [PMID: 26149094 DOI: 10.1016/j.exer.2015.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/17/2015] [Accepted: 07/02/2015] [Indexed: 01/19/2023]
Abstract
αA- and αB-crystallins are small heat shock proteins that bind thermodynamically destabilized proteins thereby inhibiting their aggregation. Highly expressed in the mammalian lens, the α-crystallins have been postulated to play a critical role in the maintenance of lens optical properties by sequestering age-damaged proteins prone to aggregation as well as through a multitude of roles in lens epithelial cells. Here, we have examined the role of α-crystallins in the development of the vertebrate zebrafish lens. For this purpose, we have carried out morpholino-mediated knockdown of αA-, αBa- and αBb-crystallin and characterized the gross morphology of the lens. We observed lens abnormalities, including increased reflectance intensity, as a consequence of the interference with expression of these proteins. These abnormalities were less frequent in transgenic zebrafish embryos expressing rat αA-crystallin suggesting a specific role of α-crystallins in embryonic lens development. To extend and confirm these findings, we generated an αA-crystallin knockout zebrafish line. A more consistent and severe lens phenotype was evident in maternal/zygotic αA-crystallin mutants compared to those observed by morpholino knockdown. The penetrance of the lens phenotype was reduced by transgenic expression of rat αA-crystallin and its severity was attenuated by maternal αA-crystallin expression. These findings demonstrate that the role of α-crystallins in lens development is conserved from mammals to zebrafish and set the stage for using the embryonic lens as a model system to test mechanistic aspects of α-crystallin chaperone activity and to develop strategies to fine-tune protein-protein interactions in aging and cataracts.
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Affiliation(s)
- Ping Zou
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Shu-Yu Wu
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Hanane A Koteiche
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Sanjay Mishra
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Daniel S Levic
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Ela Knapik
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Wenbiao Chen
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.
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14
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Unlu G, Levic DS, Melville DB, Knapik EW. Trafficking mechanisms of extracellular matrix macromolecules: insights from vertebrate development and human diseases. Int J Biochem Cell Biol 2013; 47:57-67. [PMID: 24333299 DOI: 10.1016/j.biocel.2013.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 11/01/2013] [Accepted: 11/10/2013] [Indexed: 12/19/2022]
Abstract
Cellular life depends on protein transport and membrane traffic. In multicellular organisms, membrane traffic is required for extracellular matrix deposition, cell adhesion, growth factor release, and receptor signaling, which are collectively required to integrate the development and physiology of tissues and organs. Understanding the regulatory mechanisms that govern cargo and membrane flow presents a prime challenge in cell biology. Extracellular matrix (ECM) secretion remains poorly understood, although given its essential roles in the regulation of cell migration, differentiation, and survival, ECM secretion mechanisms are likely to be tightly controlled. Recent studies in vertebrate model systems, from fishes to mammals and in human patients, have revealed complex and diverse loss-of-function phenotypes associated with mutations in components of the secretory machinery. A broad spectrum of diseases from skeletal and cardiovascular to neurological deficits have been linked to ECM trafficking. These discoveries have directly challenged the prevailing view of secretion as an essential but monolithic process. Here, we will discuss the latest findings on mechanisms of ECM trafficking in vertebrates.
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Affiliation(s)
- Gokhan Unlu
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel S Levic
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - David B Melville
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ela W Knapik
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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15
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Venkateswaran A, Sekhar KR, Levic DS, Melville DB, Clark TA, Rybski WM, Walsh AJ, Skala MC, Crooks PA, Knapik EW, Freeman ML. The NADH oxidase ENOX1, a critical mediator of endothelial cell radiosensitization, is crucial for vascular development. Cancer Res 2013; 74:38-43. [PMID: 24247717 DOI: 10.1158/0008-5472.can-13-1981] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
ENOX1 is a highly conserved NADH oxidase that helps to regulate intracellular nicotinamide adenine dinucleotide levels in many cell types, including endothelial cells. Pharmacologic and RNA interference (RNAi)-mediated suppression of ENOX1 impairs surrogate markers of tumor angiogenesis/vasculogenesis, providing support for the concept that ENOX1 represents an antiangiogenic druggable target. However, direct genetic evidence that demonstrates a role for ENOX1 in vascular development is lacking. In this study, we exploited a zebrafish embryonic model of development to address this question. Whole-mount in situ hybridization coupled with immunofluorescence performed on zebrafish embryos demonstrate that enox1 message and translated protein are expressed in most tissues, and its expression is enriched in blood vessels and heart. Morpholino-mediated suppression of Enox1 in Tg(fli1-eGFP) and Tg(flk1-eGFP) zebrafish embryos significantly impairs the development of vasculature and blood circulation. Using in vivo multiphoton microscopy, we show that morpholino-mediated knockdown of enox1 increases NADH levels, consistent with loss of enzyme. VJ115 is a small-molecule inhibitor of Enox1's oxidase activity shown to increase intracellular NADH in endothelial cells; we used VJ115 to determine if the oxidase activity was crucial for vascular development. We found that VJ115 suppressed vasculogenesis in Tg(fli1-eGFP) embryos and impaired circulation. Previously, it was shown that suppression of ENOX1 radiosensitizes proliferating tumor vasculature, a consequence of enhanced endothelial cell apoptosis. Thus, our current findings, coupled with previous research, support the hypothesis that ENOX1 represents a potential cancer therapy target, one that combines molecular targeting with cytotoxic sensitization.
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Affiliation(s)
- Amudhan Venkateswaran
- Authors' Affiliations: Departments of Radiation Oncology and Medicine and Cell & Developmental Biology; Genomic Sciences Resources, Vanderbilt University Medical Center; Biomedical Engineering, Vanderbilt School of Engineering, Nashville, Tennessee; School of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas; and Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California
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16
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Venkateswaran A, Levic DS, Melville DB, Sekhar KR, Walsh AJ, Skala MC, Crooks PA, Knapik EW, Freeman ML. Abstract 384: NADH oxidase, Enox1 activity, is required for vasculogenesis in Zebrafish. Cancer Res 2013. [DOI: 10.1158/1538-7445.am2013-384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Establishment of an adequate vascular network is a crucial event for tumor development. Emerging research has implicated the endothelial redox state as a significant regulator of vascular growth and remodeling. ENOX1 encodes a protein that is expressed in mammalian endothelial cells and exhibits NADH oxidase activity. Recent research suggests that ENOX1 functions as a positive regulator of angiogenesis. However, direct genetic evidence supporting this hypothesis is lacking. We used a zebrafish model to directly examine the role of Enox1 during embryonic vascular development. Whole mount in situ hybridization coupled with immunocytochemistry performed on zebrafish cryosections show that enox1 message and the translated protein are expressed in heart and blood vessels during embryonic development. Furthermore, use of immunocytochemistry demonstrates that Enox1 co-localizes with vascular expression of the ETS-domain transcription factor fli in heart and intersegmental vessels. Using in vivo multiphoton microscopy, we show that morpholino-mediated knockdown of Enox1 in Zebrafish embryos increases NADH fluorescence, an expected consequence of loss of Enox1 oxidase activity. Phenotypic manifestations resulting from loss of Enox1 function in embryos include vascular defects, most notably loss of fli-eGFP and flk-eGFP (receptor kdr, VEGFR2 in mammals) expression in intersegmental vessels and a loss of blood circulation in the intersegmental vessels. Pharmacological inhibition of Enox1 activity using a novel small molecule phenocopies the defects observed following morpholino-mediated functional knockdown. Together, these results show that Enox1-mediated redox regulation is essential for vasculogenesis in vertebrates in vivo. These results, in conjunction with previous work that demonstrated that inhibition of ENOX1 radiosensitized tumor vasculature, support the hypothesis that ENOX1 represents a novel target for impairing tumor angiogenesis.
Citation Format: Amudhan Venkateswaran, Daniel S. Levic, David B. Melville, Konjeti R. Sekhar, Alexandra J. Walsh, Melissa C. Skala, Peter A. Crooks, Ela W. Knapik, Michael L. Freeman. NADH oxidase, Enox1 activity, is required for vasculogenesis in Zebrafish. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 384. doi:10.1158/1538-7445.AM2013-384
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Affiliation(s)
| | | | | | | | | | | | - Peter A. Crooks
- 3University of Arkansas for Medical Sciences, Little Rock, AR
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Eames BF, Yan YL, Swartz ME, Levic DS, Knapik EW, Postlethwait JH, Kimmel CB. Mutations in fam20b and xylt1 reveal that cartilage matrix controls timing of endochondral ossification by inhibiting chondrocyte maturation. PLoS Genet 2011; 7:e1002246. [PMID: 21901110 PMCID: PMC3161922 DOI: 10.1371/journal.pgen.1002246] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [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] [Received: 01/23/2011] [Accepted: 07/01/2011] [Indexed: 11/18/2022] Open
Abstract
Differentiating cells interact with their extracellular environment over time. Chondrocytes embed themselves in a proteoglycan (PG)-rich matrix, then undergo a developmental transition, termed "maturation," when they express ihh to induce bone in the overlying tissue, the perichondrium. Here, we ask whether PGs regulate interactions between chondrocytes and perichondrium, using zebrafish mutants to reveal that cartilage PGs inhibit chondrocyte maturation, which ultimately dictates the timing of perichondral bone development. In a mutagenesis screen, we isolated a class of mutants with decreased cartilage matrix and increased perichondral bone. Positional cloning identified lesions in two genes, fam20b and xylosyltransferase1 (xylt1), both of which encode PG synthesis enzymes. Mutants failed to produce wild-type levels of chondroitin sulfate PGs, which are normally abundant in cartilage matrix, and initiated perichondral bone formation earlier than their wild-type siblings. Primary chondrocyte defects might induce the bone phenotype secondarily, because mutant chondrocytes precociously initiated maturation, showing increased and early expression of such markers as runx2b, collagen type 10a1, and ihh co-orthologs, and ihha mutation suppressed early perichondral bone in PG mutants. Ultrastructural analyses demonstrated aberrant matrix organization and also early cellular features of chondrocyte hypertrophy in mutants. Refining previous in vitro reports, which demonstrated that fam20b and xylt1 were involved in PG synthesis, our in vivo analyses reveal that these genes function in cartilage matrix production and ultimately regulate the timing of skeletal development.
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Affiliation(s)
- B Frank Eames
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America.
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18
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Melville DB, Montero-Balaguer M, Levic DS, Bradley K, Smith JR, Hatzopoulos AK, Knapik EW. The feelgood mutation in zebrafish dysregulates COPII-dependent secretion of select extracellular matrix proteins in skeletal morphogenesis. Dis Model Mech 2011; 4:763-76. [PMID: 21729877 PMCID: PMC3209646 DOI: 10.1242/dmm.007625] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Craniofacial and skeletal dysmorphologies account for the majority of birth defects. A number of the disease phenotypes have been attributed to abnormal synthesis, maintenance and composition of extracellular matrix (ECM), yet the molecular and cellular mechanisms causing these ECM defects remain poorly understood. The zebrafish feelgood mutant manifests a severely malformed head skeleton and shortened body length due to defects in the maturation stage of chondrocyte development. In vivo analyses reveal a backlog of type II and type IV collagens in rough endoplasmic reticulum (ER) similar to those found in coat protein II complex (COPII)-deficient cells. The feelgood mutation hinders collagen deposition in the ECM, but trafficking of small cargos and other large ECM proteins such as laminin to the extracellular space is unaffected. We demonstrate that the zebrafish feelgood mutation causes a single amino acid substitution within the DNA-binding domain of transcription factor Creb3l2. We show that Creb3l2 selectively regulates the expression of genes encoding distinct COPII proteins (sec23a, sec23b and sec24d) but find no evidence for its regulation of sec24c expression. Moreover, we did not detect activation of ER stress response genes despite intracellular accumulation of collagen and prominent skeletal defects. Promoter trans-activation assays show that the Creb3l2 feelgood variant is a hypomorphic allele that retains approximately 50% of its transcriptional activity. Transgenic rescue experiments of the feelgood phenotype restore craniofacial development, illustrating that a precise level of Creb3l2 transcriptional activity is essential for skeletogenesis. Our results indicate that Creb3l2 modulates the availability of COPII machinery in a tissue- and cargo-specific manner. These findings could lead to a better understanding of the etiology of human craniofacial and skeletal birth defects as well as adult-onset diseases that are linked to dysregulated ECM deposition, such as arthritis, fibrosis or osteoporosis.
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Affiliation(s)
- David B Melville
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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